WorldWideScience

Sample records for solidified zrsub 76nisub

  1. Phase transformations in the rapidly solidified Ti{sub 40}Zr{sub 20}Hf{sub 20}Pd{sub 20} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, N. [Division of Engineering Materials, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Yao Kefu [Division of Engineering Materials, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China)], E-mail: kfyao@tsinghua.edu.cn; Louzguine-Luzgin, D.V. [Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan); Qiu Shengbao [Division of Engineering Materials, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Ranganathan, S. [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India); Inoue, A. [Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

    2007-10-15

    We report that an approximant phase was initially obtained in amorphous Ti{sub 40}Zr{sub 20}Hf{sub 20}Pd{sub 20} alloy. In the initial stage of the devitrification process, the approximant phase transforms into an icosahedral (I) phase with a high thermal stability while the cF96 Zr{sub 2}Ni-type (space group Fd3-bar m with a=1.25nm and 96 atoms cell{sup -1}) particles precipitate from the amorphous matrix. Eventually the I phase grows to several hundred nanometers when annealed at about 1000K and then transforms into the Zr{sub 2}Ni-type phase with an endothermic reaction.

  2. Growth and microstructure formation of isothermally-solidified Zircaloy-4 joints brazed by a Zr–Ti–Cu–Ni amorphous alloy ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.H. [University of Science and Technology, Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Lim, C.H. [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Lee, J.G., E-mail: jglee88@kaeri.re.kr [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Lee, M.K.; Rhee, C.K. [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of)

    2013-10-15

    The microstructure and growth characteristics of Zircaloy-4 joints brazed by a Zr{sub 48}Ti{sub 16}Cu{sub 17}Ni{sub 19} (at.%) amorphous filler metal have been investigated with regard to the controlled isothermal solidification and intermetallic formation. Two typical joints were produced depending on the isothermal brazing temperature: (1) a dendritic growth structure including bulky segregation in the central zone (at 850 °C), and (2) a homogeneous dendritic structure throughout the joint without segregation (at 890 °C). The primary α-Zr phase was solidified isothermally, nucleating to grow into a joint with a cellular or dendritic structure. Also, the continuous Zr{sub 2}Ni and particulate Zr{sub 2}Cu phases were formed in the segregated center zone and at the intercellular region, respectively, owing to the different solubility and atomic mobility of the solute elements (Ti, Cu, and Ni) in the α-Zr matrix. A disappearance of the central Zr{sub 2}Ni phase was also rate-controlled by the outward diffusion of the Cu and Ni elements. When the detrimental Zr{sub 2}Ni intermetallic phase was eliminated by a complete isothermal solidification at 890 °C, the strengths of the joints were high enough to cause yielding and fracture in the base metal, exceeding those of the bulk Zircaloy-4, at room temperature as well as at elevated temperatures (up to 400 °C)

  3. Radioactive substance solidifying device

    International Nuclear Information System (INIS)

    Sakoda, Kotaro.

    1979-01-01

    Purpose: To easily solidify radioactive substances adhering to the surfaces of solid wastes without scattering in the circumference by paints, and further to reduce surface contamination concentrations. Constitution: Solid wastes are placed on a hanging plate, and dipped in paints within a paint dipping treatment tank installed at the lower part of a treatment tank by means of a monorail hoist, and the surfaces of said solid wastes are coated with paints, thereby to solidify the radioactivity on the surfaces of the solid wastes. After dipping, the solid wastes are suspended up to a paint spraying tank to dry the paints. After drying, non-contaminated paints are atomized to apply through an atomizing tube onto the solid wastes. After drying the atomized paints, the solid wastes are carried outside the treatment tank by means of the monorail hoist. (Yoshino, Y.)

  4. Radioactive waste solidifying material

    International Nuclear Information System (INIS)

    Ono, Keiichi; Sakai, Etsuro.

    1989-01-01

    The solidifying material according to this invention comprises cement material, superfine powder, highly water reducing agent, Al-containing rapid curing material and coagulation controller. As the cement material, various kinds of quickly hardening, super quickly hardening and white portland cement, etc. are usually used. As the superfine powder, those having average grain size smaller by one order than that of the cement material are desirable and silica dusts, etc. by-produced upon preparing silicon, etc. are used. As the highly water reducing agent, surface active agents of high decomposing performance and comprising naphthalene sulfonate, etc. as the main ingredient are used. As the Al-containing rapidly curing material, calcium aluminate, etc. is used in an amount of less than 10 parts by weight based on 100 parts by weight of the powdery body. As the coagulation controller, boric acid etc. usually employed as a retarder is used. This can prevent dissolution or collaption of pellets and reduce the leaching of radioactive material. (T.M.)

  5. Radioactive liquid waste solidifying device

    International Nuclear Information System (INIS)

    Uchiyama, Yoshio.

    1987-01-01

    Purpose: To eliminate the requirement for discharge gas processing and avoid powder clogging in a facility suitable to the volume-reducing solidification of regenerated liquid wastes containing sodium sulfate. Constitution: Liquid wastes supplied to a liquid waste preheater are heated under a pressure higher than the atmospheric pressure at a level below the saturation temperature for that pressure. The heated liquid wastes are sprayed from a spray nozzle from the inside of an evaporator into the super-heated state and subjected to flash distillation. They are further heated to deposit and solidify the solidification components in the solidifying evaporation steams. The solidified powder is fallen downwardly and heated for removing water content. The recovered powder is vibrated so as not to be solidified and then reclaimed in a solidification storage vessel. Steams after flash distillation are separated into gas, liquid and solids by buffles. (Horiuchi, T.)

  6. Rapid solidification of Ni{sub 50}Nb{sub 28}Zr{sub 22} glass former alloy through suction-casting; Solidificacao rapida da liga formadora de fase amorfa Ni{sub 50}Nb{sub 28}Zr{sub 22} atraves de fundicao em coquilha por succao

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, M.I.; Santos, F.S.; Bolfarini, C.; Botta Filho, W.J.; Kiminami, C.S., E-mail: issao16@gmail.co [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    To select new alloys with high glass forming ability (GFA) to present amorphous structure in millimeter scale, several semi-empirical models have been developed. In the present work, a new alloy, Ni{sub 50}Nb{sub 28}Zr{sub 22}d, was designed based on the combination of topological instability lambda (A) criterion and electronegativity difference ({Delta}e). The alloy was rapidly solidified in a bulk wedge sample by cooper mold suction casting in order to investigate its amorphization. The sample was characterized by the combination of scanning electron microscopy (MEV), X-ray diffraction (XRD) and differential scanning calorimeter (DSC). For the minimum thickness of 200 {mu}m analyzed, it was found that the alloy did not show a totally amorphous structure. Factor such as low cooling rate, existence of oxides on the surface of the elements and presence of oxygen in the atmosphere of equipment did not allowed the achievement of higher amorphous thickness. (author)

  7. Method of solidifying radioactive laundry wastes

    International Nuclear Information System (INIS)

    Yasumura, Keijiro

    1984-01-01

    Purpose: To enable to solidify radioactive laundry wastes containing non-ionic liquid detergents less solidifiable by plastic solidification process in liquid laundry wastes for cloths or the likes discharged from a nuclear power plant. Method: Radioactive laundry wastes are solidified by using plastic solidifying agent comprising, as a main ingredient, unsaturated polyester resins and methylmethacrylate monomers. The plastic solidifying agents usable herein include, for example, unsaturated polyester resins prepared by condensating maleic anhydride and phthalic anhydride with propylene glycol and incorporated with methylmethacrylate monomers. The mixing ratio of the methylmethacrylate monomers is preferably 30 % by weight based on the unsaturated polyester resins. (Aizawa, K.)

  8. Method of solidifying radioactive wastes

    International Nuclear Information System (INIS)

    Fukazawa, Tetsuo; Ootsuka, Masaharu; Uetake, Naoto; Ozawa, Yoshihiro.

    1984-01-01

    Purpose: To prepare radioactive solidified wastes excellent in strength, heat resistance, weather-proof, water resistance, dampproof and low-leaching property. Method: A hardening material reactive with alkali silicates to form less soluble salts is used as a hardener for alkali silicates which are solidification filler for the radioactive wastes, and mixed with cement as a water absorbent and water to solidify the radioactive wastes. The hardening agent includes, for example, CaCO 3 , Ca(ClO 4 ) 2 , CaSiF 6 and CaSiO 3 . Further, in order to reduce the water content in the wastes and reduce the gap ratio in the solidification products, the hardener adding rate, cement adding rate and water content are selected adequately. As the result, solidification products can be prepared with no deposition of easily soluble salts to the surface thereof, with extremely low leaching of radioactive nucleides. (Kamimura, M.)

  9. Method of solidifying powderous wastes

    International Nuclear Information System (INIS)

    Kakimoto, Akira; Miyake, Takashi; Sato, Shuichi; Inagaki, Yuzo.

    1985-01-01

    Purpose: To improve the properties of solidification products, in the case of solidifying powderous wastes with thermosetting resins. Method. A solvent for the solution of the thermosetting resin is admixed with the powderous wastes into a paste-like form prior to adding the resin to the wastes, which are then mixed with the resin solution. As the result, those solidification products having the specific gravity and the compression strength more excellent than those of the conventional ones, and much higher than the reference values can be obtained. (Kamimura, M.)

  10. Solidifying processing device for radioactive waste

    International Nuclear Information System (INIS)

    Sueto, Kumiko; Toyohara, Naomi; Tomita, Toshihide; Sato, Tatsuaki

    1990-01-01

    The present invention concerns a solidifying device for radioactive wastes. Solidifying materials and mixing water are mixed by a mixer and then charged as solidifying and filling materials to a wastes processing container containing wastes. Then, cleaning water is sent from a cleaning water hopper to a mixer to remove the solidifying and filling materials deposited in the mixer. The cleaning liquid wastes are sent to a separator to separate aggregate components from cleaning water components. Then, the cleaning water components are sent to the cleaning water hopper and then mixed with dispersing materials and water, to be used again as the mixing water upon next solidifying operation. On the other hand, the aggregate components are sent to a processing mechanism as radioactive wastes. With such procedures, since the discharged wastes are only composed of the aggregates components, and the amount of the wastes are reduced, facilities and labors for the processing of cleaning liquid wastes can be decreased. (I.N.)

  11. Method of solidifying radioactive waste

    International Nuclear Information System (INIS)

    Hasegawa, Akira; Mihara, Shigeru; Yamashita, Koji; Sauda, Kenzo.

    1988-01-01

    Purpose: To obtain satisfactory plastic solidification products rapidly and more conveniently from radioactive wastes. Method: liquid wastes contain, in addition to sodium sulfate as the main ingredient, nitrates hindering the polymerizing curing reactions and various other unknown ingredients, while spent resins contain residual cationic exchange groups hindering the polymerizing reaction. Generally, as the acid value of unsaturated liquid polyester resins is lower, the number of terminal alkyd resins is small, formation of nitrates is reduced and the polymerizing curing reaction is taken place more smoothly. In view of the above, radioactive wastes obtained by dry powderization or dehydration of radioactive liquid wastes or spent resins are polymerized with unsaturated liquid polyester resins with the acid value of less than 13 to obtain plastic solidification. Thus, if the radioactive wastes contain a great amount of polymerization hindering material such as NaNO 2 , they can be solidified rapidly and conveniently with no requirement for pre-treatment. (Kamimura, Y.)

  12. Method of solidifying radioactive wastes

    International Nuclear Information System (INIS)

    Maeda, Masahiko; Kira, Satoshi; Watanabe, Naotoshi; Nagaoka, Takeshi; Akane, Junta.

    1982-01-01

    Purpose: To obtain solidification products of radioactive wastes having sufficient monoaxial compression strength and excellent in water durability upon ocean disposal of the wastes. Method: Solidification products having sufficient strength and filled with a great amount of radioactive wastes are obtained by filling and solidifying 100 parts by weight of chlorinated polyethylene resin and 100 - 500 parts by weight of particular or powderous spent ion exchange resin as radioactive wastes. The chlorinated polyethylene resin preferably used herein is prepared by chlorinating powderous or particulate polyethylene resin in an aqueous suspending medium or by chlorinating polyethylene resin dissolved in an organic solvent capable of dissolving the polyethylene resin, and it is crystalline or non-crystalline chlorinated polyethylene resin comprising 20 - 50% by weight of chlorine, non-crystalline resin with 25 - 40% by weight of chlorine being particularly preferred. (Horiuchi, T.)

  13. Microstructure of rapidly solidified materials

    Science.gov (United States)

    Jones, H.

    1984-07-01

    The basic features of rapidly solidified microstructures are described and differences arising from alternative processing strategies are discussed. The possibility of achieving substantial undercooling prior to solidification in processes such as quench atomization and chill block melt spinning can give rise to striking microstructural transitions even when external heat extraction is nominally Newtonian. The increased opportunity in laser and electron beam surface melting for epitaxial growth on the parent solid at an accelerating rate, however, does not exclude the formation of nonequilibrium phases since the required undercooling can be locally attained at the solidification front which is itself advancing at a sufficiently high velocity. The effects of fluid flow indicated particularly in melt spinning and surface melting are additional to the transformational and heat flow considerations that form the present basis for interpretation of such microstructural effects.

  14. Effects of Nb content on the Zr{sub 2}Fe intermetallic stability

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, C. E-mail: ciramos@cnea.gov.ar; Saragovi, C.; Granovsky, M.; Arias, D

    2003-02-01

    With the aim of studying the stability range of the Zr{sub 2}Fe intermetallic when adding Nb, the range of existence of the cubic ternary phase ({lambda}{sub 1}) and the corresponding two-phase field between them, four samples were analyzed, each one containing 35 at.% Fe and different at.% Nb: 0.5, 4 10 and 15. Optical and scanning electron metallographies, X-ray diffraction, microprobe analysis and Moessbauer spectroscopy were performed to determine and characterize the phases present in the samples. Results show that the Zr{sub 2}Fe compound accepts up to nearly 0.5 at.% Nb in solution, since the Zr{sub 2}Fe+{lambda}{sub 1} region is stable in the (0.5-3.5) at.% Nb range. To summarize these results an 800 deg. C section of the ternary Zr-Nb-Fe diagram, in the studied zone, was proposed.

  15. Method of solidifying radioactive solid wastes

    International Nuclear Information System (INIS)

    Fukazawa, Tetsuo; Kawamura, Fumio; Kikuchi, Makoto.

    1984-01-01

    Purpose: To obtain solidification products of radioactive wastes satisfactorily and safely with no destruction even under a high pressure atmosphere by preventing the stress concentration by considering the relationships of the elastic module between the solidifying material and radioactive solid wastes. Method: Solidification products of radioactive wastes with safety and securing an aimed safety ratio are produced by conditioning the modules of elasticity of the solidifying material equal to or less than that of the radioactive wastes in a case where the elastic module of radioactive solid wastes to be solidified is smaller than that of the solidifying material (the elastic module of wastes having the minimum elastic module among various wastes). The method of decreasing the elastic module of the solidifying material usable herein includes the use of such a resin having a long distance between cross-linking points of a polymer in the case of plastic solidifying materials, and addition of rubber-like binders in the case of cement or like other inorganic solidifying materials. (Yoshihara, H.)

  16. Liquid wastes concentrating and solidifying device

    International Nuclear Information System (INIS)

    Kamiyoshi, Hideki; Ninokata, Yoshihide.

    1985-01-01

    Purpose: To provide a device for concentrating to solidify radioactive liquid wastes at large solidifying speed and with high decontaminating coefficient, without requirement for automatic control. Constitution: An asphalt solidifying device is disposed below a centrifugal thin film drier, and powder resulted from the drier is directly solidified with asphalt by utilizing the rotation of the drier for the mixing operation in the asphalt vessel. If abnormality should occur in the operation of the drier, resulting liquid wastes can be received and solidified in the asphalt vessel. The liquid wastes are heated to dry in a vessel main body having the heating surface at the circumferential surface. The vessel main body provided with a nozzle for supplying liquid to be treated disposed slantwise at the upper portion of the heating face, scrapers which rotate and slidingly contact the heating face and nozzles which jet out chemicals to the heating face behind the scrapers. Below the vessel main body, are disposed a funnel-like hopper for receiving falling scales, rotary vanes, and the likes by which the scales are introduced into the asphalt solidifying vessel. (Moriyama, K.)

  17. Method of solidifying radioactive wastes with plastics

    International Nuclear Information System (INIS)

    Matsuura, Hiroyuki; Yasumura, Keijiro; Minami, Yuji; Tomita, Toshihide

    1980-01-01

    Purpose: To prevent solidification of solidifying agents in the mixer by conducting the mixing process for the solidifying agents and the radioactive wastes at a temperature below the initiation point for the solidification of the agents thereby separating the mixing process from the solidification-integration process. Method: Catalyst such as cobalt naphthenate is charged into an unsaturated polyester resin in a mixer previously cooled, for example, to -10 0 C. They are well mixed with radioactive wastes and the mixture in the mixer is charged in a radioactive waste storage container. The temperature of the mixture, although kept at a low temperature initially, gradually increases to an ambient temperature whereby curing reaction is promoted and the reaction is completed about one day after to provide firm plastic solidification products. This can prevent the solidification of the solidifying agents in the mixer to thereby improve the circumstance's safety. (Kawakami, Y.)

  18. Atomic disorder in Gd{sub 2}Zr{sub 2}O{sub 7} pyrochlore

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F. X. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004 (China); Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Lang, M. [Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Ewing, R. C. [Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 (United States)

    2015-05-11

    Gd{sub 2}Zr{sub 2}O{sub 7} pyrochlore with different degrees of cation disorder were synthesized by isothermal annealing at various temperatures (1100–1550 °C), and the related changes in the structure were investigated by ambient and high pressure x-ray diffraction (XRD) measurements. Unit cell parameters increase almost linearly with increasing treatment temperature. The degree of cation order in pyrochlore also increases with the increase of temperature, but saturates at ∼60%. The compressibility of the pyrochlore structures decreases when the degree of cation order increases. High pressure XRD measurements also indicate that the phase stability of Gd{sub 2}Zr{sub 2}O{sub 7} is not very sensitive to the degree of atomic disorder in the pyrochlore structure.

  19. Rapidly solidified aluminium for optical applications

    NARCIS (Netherlands)

    Gubbels, G.P.H.; Venrooy, B.W.H. van; Bosch, A.J.; Senden, R.

    2008-01-01

    This paper present the results of a diamond turning study of a rapidly solidified aluminium 6061 alloy grade, known as RSA6061. It is shown that this small grain material can be diamond turned to smaller roughness values than standard AA6061 aluminium grades. Also, the results are nearly as good as

  20. Investigation of electronic, magnetic and thermoelectric properties of Zr{sub 2}NiZ (Z = Al,Ga) ferromagnets

    Energy Technology Data Exchange (ETDEWEB)

    Yousuf, Saleem, E-mail: nengroosaleem17@gmail.com; Gupta, Dinesh C., E-mail: sosfizix@gmail.com

    2017-05-01

    Systematic investigation of impact of electronic structure and magnetism, on the thermoelectric properties of new Zr{sub 2}NiZ (Z = Al, Ga) Heusler alloys are determined using density functional theory calculations. Half-metallicity with ferromagnetic character is supported by their 100% spin polarizations at the Fermi level. Magnetic moment of ∼3 μ{sub B} is according to the Slater-Puling rule, enables their practical applications. Electron density plots are used to analyse the nature of bonding and chemical composition. Boltzmann's theory is conveniently employed to investigate the thermoelectric properties of these compounds. The analysis of the thermal transport properties specifies the Seebeck coefficient as 25.6 μV/K and 18.6 μV/K at room temperature for Zr{sub 2}NiAl and Zr{sub 2}NiGa, respectively. The half-metallic nature with efficient thermoelectric coefficients suggests the likelihood of these materials to have application in designing spintronic devices and imminent thermoelectric materials. - Highlights: • The compounds are half-metallic ferromagnets. • 100% spin-polarized compounds for spintronics. • Increasing Seebeck coefficient over a wide temperature range. • Zr{sub 2}NiAl is efficient thermoelectric material than Zr{sub 2}NiGa.

  1. Method for solidifying powdery radioactive wastes

    International Nuclear Information System (INIS)

    Yasumura, Keijiro; Matsuura, Hiroyuki; Tomita, Toshihide.

    1978-01-01

    Purpose: To solidify powdery radioactive wastes through polymerization in a vessel at a high impregnation speed with no cloggings in pipes. Method: A drum can is lined with an inner liner layer of a predetermined thickness made of inflammable material such as glass fiber. A plurality of pipes for supplying liquid plastic monomer are provided in adjacent to the upper end face of the inflammable material or inserted between the vessel and the inflammable material. Then powdery radioactive wastes are filled in the vessel and the liquid plastic monomer dissolving therein a polymerization initiator is supplied through the pipes. The liquid plastic monomer impregnates through the inflammable material layer into the radioactive wastes and the plastic monomer is polymerized by the aid of the polymerization initiator after a predetermined of time to produce solidified plastic products of radioactive wastes. (Seki, T.)

  2. Leaching behavior of solidified plastics radioactive wastes

    International Nuclear Information System (INIS)

    Yook, Chong Chul; Lee, Byung Hun; Jae, Won Mok; Kim, Kyung Eung

    1986-01-01

    It is highly needed to develope the solidification process to dispose safely the radioactive wastes increasing with the growth of the nuclear industry. The leaching mechanisms of the solidified plastic wastes were investigated and the leaching rates of the plastic wastes were also measured among the many solidification processes. In addition, the transport equation based on the diffusion or the diffusion-dissolution was compared with the empirical equation derived from the experimental data by graphical method. Consequently, leaching process of the solidified plastic wastes is quite well agreed with the mass transport theory, but it may be difficult to simulate leaching process by diffusion dissolution mechanism. But the theoretical equation could be applicable to the cumulative amount of radionuclides leached form the plastic wastes disposed into the environment. (Author)

  3. Characterization of aluminium alloys rapidly solidified

    International Nuclear Information System (INIS)

    Monteiro, W.A.

    1988-01-01

    This paper discussed the investigation of the microstructural and mechanical properties of the aluminium alloys (3003; 7050; Al-9% Mg) rapidly solidified by melt spinning process (cooling rate 10 4 - 10 6 K/s). The rapidly solidification process of the studied aluminium alloys brought a microcrystallinity, a minimum presence of coarse precipitation and, also, better mechanical properties of them comparing to the same alloys using ingot process. (author) [pt

  4. Lattice dynamics, thermodynamics and elastic properties of C22-Zr{sub 6}FeSn{sub 2} from first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xuan-Kai [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Shi, Siqi, E-mail: sqshi@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Materials Genome Institute, Shanghai University, Shanghai 200444 (China); Shen, Jian-Yun [General Research Institute for Nonferrous Metals, Beijing 100088 (China); Shang, Shun-Li [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Yao, Mei-Yi, E-mail: yaomeiyi@shu.edu.cn [School of Materials Science and Engineering, Shanghai University, Shanghai 200444 (China); Liu, Zi-Kui [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2016-10-15

    Since Zr-Fe-Sn is one of the key ternary systems for cladding and structural materials in nuclear industry, it is of significant importance to understand physicochemical properties related to Zr-Fe-Sn system. In order to design the new Zr alloys with advanced performance by CALPHAD method, the thermodynamic model for the lower order systems is required. In the present work, first-principles calculations are employed to obtain phonon, thermodynamic and elastic properties of Zr{sub 6}FeSn{sub 2} with C22 structure and the end-members (C22-Zr{sub 6}FeFe{sub 2}, C22-Zr{sub 6}SnSn{sub 2} and C22-Zr{sub 6}SnFe{sub 2}) in the model of (Zr){sub 6}(Fe, Sn){sub 2}(Fe, Sn){sub 1}. It is found that the imaginary phonon modes are absent for C22-Zr{sub 6}FeSn{sub 2} and C22-Zr{sub 6}SnSn{sub 2}, indicating they are dynamically stable, while the other two end-members are unstable. Gibbs energies of C22-Zr{sub 6}FeSn{sub 2} and C22-Zr{sub 6}SnSn{sub 2} are obtained from the quasiharmonic phonon approach and can be added in the thermodynamic database: Nuclearbase. The C22-Zr{sub 6}FeSn{sub 2}’s single-crystal elasticity tensor components along with polycrystalline bulk, shear and Young’s moduli are computed with a least-squares approach based upon the stress tensor computed from first-principles method. The results indicate that distortion is more difficult in the directions normal the c-axis than along to it.

  5. Cation distributions on rapidly solidified cobalt ferrite

    Science.gov (United States)

    De Guire, Mark R.; Kalonji, Gretchen; O'Handley, Robert C.

    1990-01-01

    The cation distributions in two rapidly solidified cobalt ferrites have been determined using Moessbauer spectroscopy at 4.2 K in an 8-T magnetic field. The samples were obtained by gas atomization of a Co0-Fe2O3-P2O5 melt. The degree of cation disorder in both cases was greater than is obtainable by cooling unmelted cobalt ferrite. The more rapidly cooled sample exhibited a smaller departure from the equilibrium cation distribution than did the more slowly cooled sample. This result is explained on the basis of two competing effects of rapid solidification: high cooling rate of the solid, and large undercooling.

  6. Site Simulation of Solidified Peat: Lab Monitoring

    Science.gov (United States)

    Durahim, N. H. Ab; Rahman, J. Abd; Tajuddin, S. F. Mohd; Mohamed, R. M. S. R.; Al-Gheethi, A. A.; Kassim, A. H. Mohd

    2018-04-01

    In the present research, the solidified peat on site simulation is conducted to obtain soil leaching from soil column study. Few raw materials used in testing such as Ordinary Portland Cement (OPC), Fly ash (FA) and bottom ash (BA) which containing in solidified peat (SP), fertilizer (F), and rainwater (RW) are also admixed in soil column in order to assess their effects. This research was conducted in two conditions which dry and wet condition. Distilled water used to represent rainfall during flushing process while rainwater used to gain leaching during dry and wet condition. The first testing made after leaching process done was Moisture Content (MC). Secondly, Unconfined Compressive Strength (UCS) will be conducted on SP to know the ability of SP strength. These MC and UCS were made before and after SP were applied in soil column. Hence, the both results were compared to see the reliability occur on SP. All leachate samples were tested using Absorption Atomic Spectroscopy (AAS), Ion Chromatography (IC) and Inductively-Coupled Plasma Spectrophotometry (ICP-MS) testing to know the anion and cation present in it.

  7. Method and apparatus for solidifying radioactive waste

    International Nuclear Information System (INIS)

    Kadota, Hiroko; Kikuchi, Makoto; Tsuchiya, Hiroyuki; Tamada, Shin.

    1989-01-01

    The present invention concerns a method of solidifying radioactive wastes that generate heat with water curing solidifying material and the object there of is suppress the effect of heat generation of the wastes given on the solidification material. That is, it is a feature of the invention to inject water content contained in the water curable solidification material in the form of ice into the wastes. Thus, since the water content in the water curable solidification material is ice, the solidification products can be obtained by way of the following three steps: (1) ice is dissolved into water, (2) solid content of the solidification material is dissolved into water, and(3) curing reaction of the solidification material is started. Acccordingly, since the heat generated from the wastes contributes as heat of reaction when ice is dissolved into water till the solidification material has been completely filled, promotion for the curing reaction causing problems so far can be suppressed to enable easy filling. Then, after the completion of the filling of the solidification material, the heat of the wastes has an effect of promoting the second and the third steps described above to accelerate the curing reaction. (K.M.)

  8. Method and device for solidifying radioactive waste

    International Nuclear Information System (INIS)

    Hayashi, Tadamasa.

    1981-01-01

    Purpose: To solidify radioactive waste without producing radioactive dusts by always heating and evaporating the water from liquid radioactive waste in a mixture of liquid plastic and exhausting the molten mixture of the waste residue and the plastic material. Constitution: Liquid plastic material in a tank cooled to prevent polymerization or changes of its properties is continuously supplied to the top of a heating and mixing evaporator by a constant supply pump. After the heat transfer surface of the evaporator is covered with the plastic material, radioactive waste in the tank is supplied to the evaporator via the constant supply pump. The waste is abruptly mixed with the plastic material by an agitating rotor, heated by a heater, and the evaporated water is fed to a condenser. An anhydrous molten mixture is continuously exhausted from the bottom of the evaporator into a mixture cooler, a polymerizing agent and catalyst are introduced thereinto from a polymerizing agent tank and a catalyst tank, inhibitor is introduced thereinto from a polymerization inhibitor tank as required, and is filled with the mixture a solidifying container while it is cooled for its polymerization and solidification. (Yoshino, Y.)

  9. Method of solidifying radioactive waste by plastics

    International Nuclear Information System (INIS)

    Yasumura, Keijiro; Tomita, Toshihide.

    1976-01-01

    Purpose: To prevent leakage of radioactivity by providing corrosion-resistant layer on the inner surface of a waste container for radioactive waste. Constitution: The inner periphery and bottom of a drum can is lined with an non-flammable cloth of such material as asbestos. This drum is filled with a radioactive waste in the form of powder or pellets. Then, a mixture of a liquid plastic monomer and a polymerization starting agent is poured at a normal temperature, and the surface is covered with a non-flammable cloth. The plastic monomer and radioactive waste are permitted to impregnate the non-flammable cloth and are solidified there. Thus, even if the drum can is corroded at the sea bottom after disposal it in the ocean, it is possible to prevent the waste from permeating into the outer sea water because of the presence of the plastic layer on the inside. Styrene is used as the monomer. (Aizawa, K.)

  10. A process for solidifying radioactive liquid waste

    International Nuclear Information System (INIS)

    Mergan, L.M.; Cordier, J.-P.

    1981-01-01

    In a process for solidifying radioactive liquid waste, its pH is adjusted, solids precipitated and then it is concentrated to about 50% solids content using a thin film evaporator, the concentrate then being dried to powder in a heated mixer. The mixer has a heated wall and working means, e.g. a rotor and helical screw, to shear the dried concentrate from the internal walls, subdivide it into a dry particulate powder, and advance the powder to the mixer outlet. The dried particles are then encapsulated in a suitable matrix. Vapour from the mixer and evaporator is condensed and recycled after any particles have been removed from it. The mixer may both dry the concentrate and mix the dry particles with the encapsulating matrix, and possibly, part of the mixer may be used for pH adjustment and precipitation. (author)

  11. Method of solidifying radioactive liquid wastes

    International Nuclear Information System (INIS)

    Uetake, Naoto; Kawamura, Fumio; Kikuchi, Makoto; Fukazawa, Tetsuo.

    1983-01-01

    Purpose: To enable to confine the volatiling ingredients such as cesium in liquid wastes safely in glass solidification products while suppressing the volatilization thereof. Method: Acid salt of tetravalent metal such as titanium phosphate has an intense selective adsorption property to cesium. So liquid wastes stored in a high level liquid wastes tank is mixed with titanium phosphate gels stored in an adsorbent tank, then supplied to a mixer and mixed with a sodium silicate solution stored in a sodium silicate storage tank and boric acid stored in an additive tank, into gel-like state. The gel-like material thus formed is supplied to a drier. After being dried at a temperature of 200sup(o)C - 300sup(o)C, the material is melted under heating at a temperature of 1000sup(o)C - 1100sup(o)C, and then cooled to solidify. (Horiuchi, T.)

  12. Method for accelerated leaching of solidified waste

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Heiser, J.H.; Pietrzak, R.F.; Franz, E.M.; Colombo, P.

    1990-11-01

    An accelerated leach test method has been developed to determine the maximum leachability of solidified waste. The approach we have taken is to use a semi-dynamic leach test; that is, the leachant is sampled and replaced periodically. Parameters such as temperature, leachant volume, and specimen size are used to obtain releases that are accelerated relative to other standard leach tests and to the leaching of full-scale waste forms. The data obtained with this test can be used to model releases from waste forms, or to extrapolate from laboratory-scale to full-scale waste forms if diffusion is the dominant leaching mechanism. Diffusion can be confirmed as the leaching mechanism by using a computerized mathematical model for diffusion from a finite cylinder. We have written a computer program containing several models including diffusion to accompany this test. The program and a Users' Guide that gives screen-by-screen instructions on the use of the program are available from the authors. 14 refs., 4 figs., 1 tab

  13. Leaching behavior of cement solidified materials

    International Nuclear Information System (INIS)

    2002-03-01

    An immersion test of mortar was carried out in order to solidify waste with uranium. The sample consists of 2000g cement, 950g ion exchange water, 1600g sound and 1g water reducing agent. The solid sample and ion exchange water (100 of immersion liquid/original sample) was put into polystyrene closed vessel in globe box and kept four weeks, and then it was separated to the immersion liquid and the solid phase. New ion exchange water was added to the solid and kept four weeks and then separated. Its ratio showed 200. The analysis was done at 100, 200 and 300 ratio of immersion liquid/sample. The solid phase was studied by the powder X-ray diffraction analysis, thermo gravimetric analysis and chemical analysis. The liquid phase was determined by pH values and composition analysis. The results showed Ca(OH) 2 , cement hydrate, was flowed out and it was not found in the solid phase at 200 ratio. (S.Y.)

  14. Leaching studies of radionuclides from solidified wastes with thermosetting resin

    International Nuclear Information System (INIS)

    Suzuki, K.; Kuribayashi, H.; Morimitsu, W.; Ono, I.

    1982-01-01

    This paper reports on studies of the leachability of Co-60 and Cs-137 from simulated LWR radwastes solidified with thermosetting resin and evaluates the effects of chemical fixation on leachability. It is concluded that insolubilization by a nickel-ferrocyanide compound offers an effective chemical fixation of these radionuclides and is a recommended pretreating method for radwastes that are to be solidified. 2 figures

  15. Crystallization of Zr>2PdxCu1-x and Zr>2NixCu1-x Metallic Glass

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Min [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr>2PdxCu1-x and Zr>2NixCu1-x (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction (HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr>2PdxCu1-x and Zr>2NixCu1-x metallic glass have been explored. All Zr>2PdxCu1-x compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr>2PdxCu1-x system. Meta-stable C16 phase is competitive with

  16. Biodegradation testing of solidified low-level waste streams

    International Nuclear Information System (INIS)

    Piciulo, P.L.; Shea, C.E.; Barletta, R.E.

    1985-05-01

    The NRC Technical Position on Waste Form (TP) specifies that waste should be resistant to biodegradation. The methods recommended in the TP for testing resistance to fungi, ASTM G21, and for testing resistance to bacteria, ASTM G22, were carried out on several types of solidified simulated wastes, and the effect of microbial activity on the mechanical strength of the materials tested was examined. The tests are believed to be sufficient for distinguishing between materials that are susceptible to biodegradation and those that are not. It is concluded that failure of these tests should not be regarded of itself as an indication that the waste form will biodegrade to an extent that the form does not meet the stability requirements of 10 CFR Part 61. In the case of failure of ASTM G21 or ASTM G22 or both, it is recommended that additional data be supplied by the waste generator to demonstrate the resistance of the waste form to microbial degradation. To produce a data base on the applicability of the biodegradation tests, the following simulated laboratory-scale waste forms were prepared and tested: boric acid and sodium sulfate evaporator bottoms, mixed-bed bead resins and powdered resins each solidified in asphalt, cement, and vinyl ester-styrene. Cement solidified wastes supported neither fungal nor bacterial growth. Of the asphalt solidified wastes, only the forms of boric acid evaporator bottoms did not support fungal growth. Bacteria grew on all of the asphalt solidified wastes. Cleaning the surface of these waste forms did not affect bacterial growth and had a limited effect on the fungal growth. Only vinyl esterstyrene solidified sodium sulfate evaporator bottoms showed viable fungi cultures, but surface cleaning with solvents eliminated fungal growth in subsequent testing. Some forms of all the waste streams solidified in vinyl ester-styrene showed viable bacteria cultures. 13 refs., 12 tabs

  17. Parameters of Solidifying Mixtures Transporting at Underground Ore Mining

    Directory of Open Access Journals (Sweden)

    Golik Vladimir

    2017-01-01

    Full Text Available The article is devoted to the problem of providing mining enterprises with solidifying filling mixtures at underground mining. The results of analytical studies using the data of foreign and domestic practice of solidifying mixtures delivery to stopes are given. On the basis of experimental practice the parameters of transportation of solidifying filling mixtures are given with an increase in their quality due to the effect of vibration in the pipeline. The mechanism of the delivery process and the procedure for determining the parameters of the forced oscillations of the pipeline, the characteristics of the transporting processes, the rigidity of the elastic elements of pipeline section supports and the magnitude of vibrator’ driving force are detailed. It is determined that the quality of solidifying filling mixtures can be increased due to the rational use of technical resources during the transportation of mixtures, and as a result the mixtures are characterized by a more even distribution of the aggregate. The algorithm for calculating the parameters of the pipe vibro-transport of solidifying filling mixtures can be in demand in the design of mineral deposits underground mining technology.

  18. Parameters of Solidifying Mixtures Transporting at Underground Ore Mining

    Science.gov (United States)

    Golik, Vladimir; Dmitrak, Yury

    2017-11-01

    The article is devoted to the problem of providing mining enterprises with solidifying filling mixtures at underground mining. The results of analytical studies using the data of foreign and domestic practice of solidifying mixtures delivery to stopes are given. On the basis of experimental practice the parameters of transportation of solidifying filling mixtures are given with an increase in their quality due to the effect of vibration in the pipeline. The mechanism of the delivery process and the procedure for determining the parameters of the forced oscillations of the pipeline, the characteristics of the transporting processes, the rigidity of the elastic elements of pipeline section supports and the magnitude of vibrator' driving force are detailed. It is determined that the quality of solidifying filling mixtures can be increased due to the rational use of technical resources during the transportation of mixtures, and as a result the mixtures are characterized by a more even distribution of the aggregate. The algorithm for calculating the parameters of the pipe vibro-transport of solidifying filling mixtures can be in demand in the design of mineral deposits underground mining technology.

  19. Energy asymmetry in melting and solidifying processes of PCM

    International Nuclear Information System (INIS)

    Jin, Xing; Hu, Huoyan; Shi, Xing; Zhang, Xiaosong

    2015-01-01

    Highlights: • The melting process and the solidifying process of PCM were asymmetrical. • The enthalpy and state of PCM were affected by its previous state. • The main reason for energy asymmetry of PCM was supercooling. - Abstract: The solidifying process of phase change material (PCM) was usually recognized as the exact inverse process of its melting process, especially when building the heat transfer model of PCM. To figure out that whether the melting process and the solidifying process of PCM were symmetrical, several kinds of PCMs were tested by a differential scanning calorimeter (DSC) in this paper. The experimental results showed that no matter using the DSC dynamic measurement method or the DSC step measurement method, the melting process and the solidifying process of PCM were asymmetrical. Because of the energy asymmetry in the melting and solidifying processes of PCM, it was also found that the enthalpy and the state of PCM were not only dependent on its temperature, but also affected by its “previous state”.

  20. The Thermodynamic Characterization of ZrCo–H, HfCo−H, HfNi−H and Zr{sub 1–x}HfxNi(Co) Alloy–H Systems

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, Ted B., E-mail: ted.flanagan@uvm.edu; Noh, Hak; Luo, Suifang

    2016-08-25

    ZrCo and HfCo intermetallic compounds have the same cubic (CsCl-type) structure and their ternary (Zr{sub 1−x}Hf{sub x})Co alloys are also cubic. ZrNi and HfNi intermetallic compounds have the orthorhombic structure (CrB-type) and the ternary (Zr{sub 1−x}Hf{sub x})Ni alloys also have this structure. Thermodynamic data for hydride formation and decomposition in ZrCo, HfCo and HfNi intermetallic compounds have been determined from reaction calorimetry and from pressure-composition isotherms. Thermodynamic data have been determined for the three ternary alloys: (Zr{sub 0.75}Hf{sub 0.25})Co, (Zr{sub 0.50}Hf{sub 0.50})Co, and (Zr{sub 0.25}Hf{sub 0.75})Co and the four ternary alloys: (Zr{sub 0.875}Hf{sub 0.125})Ni, (Zr{sub 0.75}Hf{sub 0.25})Ni, (Zr{sub 0.50}Hf{sub 0.50})Ni, and (Zr{sub 0.25}Hf{sub 0.75})Ni. This offers the opportunity to learn how the thermodynamic properties of the ternary alloy-H systems change with the stoichiometry of alloys with the same structure. - Highlights: • Calorimetric enthalpies determined for H absorption by ZrCo, HfCo, HfNi are determined. • Ternary alloys, e.g., Zr{sub 1−x}Hf{sub x}Ni, prepared and characterized by x-ray diffraction. • Isotherms for the ternary alloys give thermodynamic parameters for H solution.

  1. Structural relaxation and embrittlement of Cu/sub 59/Zr/sub 41/ and Fe/sub 80/B/sub 20/ glasses

    International Nuclear Information System (INIS)

    Deng, D.; Argon, A.S.

    1986-01-01

    The effect of physical aging at 0.92 T/sub c/, on phase separation, crystallization, distributed shear relaxations, hardness, and strain to fracture was investigated in Cu/sub 59/Zr/sub 41/ and Fe/sub 80/B/sub 20/ glasses. In Cu/sub 59/Zr/sub 41/ glass, aging resulted in phase separation prior to crystallization, rather than the expected polymorphous crystallization. In Fe/sub 80/B/sub 20/ in the as-quenched alloys a prominent second-order Curie transition was found at 613K, which was recovered by aging. Apart from a nearly four-fold acceleration of the aging process in Fe/sub 80/B/sub 20/ over the Cu/sub 59/Zr/sub 41/ alloy, their mechanical responses to the aging were very similar in alterations of the internal friction spectrum, evolution of hardness, and strain to fracture

  2. Method of solidifying and disposing radioactive waste plastic

    International Nuclear Information System (INIS)

    Matsuura, Hiroyuki; Yasumura, Keijiro

    1981-01-01

    Purpose: To solidify radioactive waste as it is with plastic by forming a W/O (Water-in-Oil) emulsion with the radioactive waste and a plastic solidifier, and treating it with a polymerization starting agent, an accelerator, and the like. Method: A predetermined amount of alkaline substance such as sodium hydroxide, triethanol, or the like is added quantitatively to radioactive waste and it is mixed by an agitator. A predetermined amount of solidifier such as unsaturated polyester or the like is added to the mixture and it is further mixed by the agitator to form a stable W/O emulsion. Subsequently, predetermined amounts of polymerization starting agent such as methyl ethyl ketone peroxide and polymerization accelerator such as cobalt naphthenate or the like are added thereto, the mixture is mixed, and is then allowed to stand for at room temperature for the plastic solidification thereof. No reaction occurs after the solidification. (Sekiya, K.)

  3. Detection of free liquid in containers of solidified radioactive waste

    Science.gov (United States)

    Greenhalgh, Wilbur O.

    1985-01-01

    A method of nondestructively detecting the presence of free liquid within a sealed enclosure containing solidified waste by measuring the levels of waste at two diametrically opposite locations while slowly tilting the enclosure toward one of said locations. When the measured level remains constant at the other location, the measured level at said one location is noted and any measured difference of levels indicates the presence of liquid on the surface of the solidified waste. The absence of liquid in the enclosure is verified when the measured levels at both locations are equal.

  4. Evaluation of solidified high-level waste forms

    International Nuclear Information System (INIS)

    1981-01-01

    One of the objectives of the IAEA waste management programme is to coordinate and promote development of improved technology for the safe management of radioactive wastes. The Agency accomplished this objective specifically through sponsoring Coordinated Research Programmes on the ''Evaluation of Solidified High Level Waste Products'' in 1977. The primary objectives of this programme are to review and disseminate information on the properties of solidified high-level waste forms, to provide a mechanism for analysis and comparison of results from different institutes, and to help coordinate future plans and actions. This report is a summary compilation of the key information disseminated at the second meeting of this programme

  5. Site suitability criteria for solidified high level waste repositories

    International Nuclear Information System (INIS)

    Heckman, R.A.; Holdsworth, T.; Towse, D.F.

    1979-01-01

    Activities devoted to development of regulations, criteria, and standards for storage of solidified high-level radioactive wastes are reported. The work is summarized in sections on site suitability regulations, risk calculations, geological models, aquifer models, human usage model, climatology model, and repository characteristics. Proposed additional analytical work is also summarized

  6. Characteristics of solidified high-level waste products

    International Nuclear Information System (INIS)

    1979-01-01

    The object of the report is to contribute to the establishment of a data bank for future preparation of codes of practice and standards for the management of high-level wastes. The work currently in progress on measuring the properties of solidified high-level wastes is being studied

  7. Amorphous phase formation in the Cu{sub 36}Zr{sub 59}A{sub l5} and Cu{sub 48}Zr{sub 43}A{sub l9} ternary alloys studied by molecular dynamics; Estudo da formacao de fase amorfa nas ligas ternarias Cu{sub 36}Zr{sub 59}A{sub l5} e Cu{sub 48}Zr{sub 43}A{sub l9} por dinamica molecular

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, L.C.R.; Schimidt, C.S.; Lima, L.V.; Domingues, G.M.B.; Bastos, I.N., E-mail: aliaga@iprj.uer.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova friburgo, RJ (Brazil). Departamento de Materiais

    2016-07-01

    Amorphous alloys presents better mechanical and physical properties than its crystalline counterparts. However, there is a scarce understanding on structure - properties relationship in this class of materials. This paper presents the results of the molecular dynamics application to obtain an atomistic description of melting, solidification and the glass forming ability in the ternary Cu{sub 36}Zr{sub 59}A{sub l5} and Cu{sub 48}Zr{sub 43}A{sub l9} alloys. In the study we used the EAM potential and different cooling rates, β = 0.1, 1 and 100 K/ps to form the amorphous phase in a system consisting of 32,000 atoms by using the free code LAMMPS. The solidus and liquidus temperatures, on a heating rate of the 5 K/ps, were obtained. Also, on the cooling down step, it was observed that the glass transition temperature (T{sub g}) decreases as cooling rate increases. The structural evolution was analyzed through the radial distribution functions and Voronoi polyhedra. Furthermore, it was determined the evolution of viscosity upper T{sub g}, as well as the fragility (m) parameter for each amorphous alloy. The thermal parameters of the simulation obtained are compared with those of the experiments. (author)

  8. Hydrogenation study of suction-cast Ti{sub 40}Zr{sub 40}Ni{sub 20} quasicrystal

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Huogen; Li, Rong; Yin, Chen; Zheng, Shaotao; Zhang, Pengcheng [National Key Laboratory for Surface Physics and Chemistry, P.O. Box 718-35, Mian Yang 621907, Sichuan (China)

    2008-09-15

    Suction casting was predicted to be an usable method for improving the hydriding kinetics of Ti/Zr-based icosahedral quasicrystals (IQCs) in our previous work. To further determine it, a suction-cast Ti{sub 40}Zr{sub 40}Ni{sub 20} IQC alloy was used for hydrogenation studies by Pressure Composition Isotherm (PCI) and Temperature Programmed Desorption (TPD) techniques. The results showed that, this alloy absorbed hydrogen rapidly with obvious hydrogen pressure plateau and some reversibility, however, displayed very limited hydrogen capacity (about 0.7 wt.%) and low equilibrium pressure. After several hydrogenation/dehydrogenation cycles, the IQC structure transformed into two hydride phases, ZrH{sub 2-x} and one unknown, both of which decomposed at above 600 C, suggesting high thermo-stability for them. On the whole, indeed the suction-casting method can increase the hydrogen absorption rate of Ti/Zr-based IQCs, however, the hydrogenation properties of the Ti{sub 40}Zr{sub 40}Ni{sub 20} IQC alloy still need a mighty advancement. (author)

  9. Thermodynamic properties and solidification kinetics of intermetallic Ni{sub 7}Zr{sub 2} alloy investigated by electrostatic levitation technique and theoretical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Li, L. H.; Hu, L.; Yang, S. J.; Wang, W. L.; Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2016-01-21

    The thermodynamic properties, including the density, volume expansion coefficient, ratio of specific heat to emissivity of intermetallic Ni{sub 7}Zr{sub 2} alloy, have been measured using the non-contact electrostatic levitation technique. These properties vary linearly with temperature at solid and liquid states, even down to the obtained maximum undercooling of 317 K. The enthalpy, glass transition, diffusion coefficient, shear viscosity, and surface tension were obtained by using molecular dynamics simulations. Ni{sub 7}Zr{sub 2} has a relatively poor glass forming ability, and the glass transition temperature is determined as 1026 K. The inter-diffusivity of Ni{sub 7}Zr{sub 2} alloy fitted by Vogel–Fulcher–Tammann law yields a fragility parameter of 8.49, which indicates the fragile nature of this alloy. Due to the competition of increased thermodynamic driving force and decreased atomic diffusion, the dendrite growth velocity of Ni{sub 7}Zr{sub 2} compound exhibits double-exponential relationship to the undercooling. The maximum growth velocity is predicted to be 0.45 m s{sup −1} at the undercooling of 335 K. Theoretical analysis reveals that the dendrite growth is a diffusion-controlled process and the atomic diffusion speed is only 2.0 m s{sup −1}.

  10. Structures, stabilities, and electronic properties of small-sized Zr{sub 2}Si{sub n} (n=1-11) clusters. A density functional study

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jing-He; Liu, Chang-Xin [Henan Institute of Education, Zhengzhou (China). Dept. of Physics; Wang, Ping; Zhang, Shuai; Lu, Cheng [Nanyang Normal Univ (China). Dept. of Physics; Yang, Gui [Anyang Normal Univ. (China). Dept. of Physics and Electrical Engineering

    2015-07-01

    Ab initio methods based on density functional theory at B3LYP level have been applied in investigating the equilibrium geometries, growth patterns, relative stabilities, and electronic properties of Zr{sub 2}-doped Si{sub n} clusters. The optimisation results shown that the lowest-energy configurations for Zr{sub 2}Si{sub n} clusters do not keep the corresponding silicon framework unchanged, which reflects that the doped Zr atoms dramatically affect the most stable structures of the Si{sub n} clusters. By analysing the relative stabilities, it is found that the doping of zirconium atoms reduces the chemical stabilities of silicon host. The Zr{sub 2}Si{sub 4} and Zr{sub 2}Si{sub 7} clusters are the magic numbers. The natural population and natural electronic configuration analyses indicated that the Zr atoms possess positive charge for n=1-6 and negative charge for n=7-11. In addition, the chemical hardness, chemical potential, infrared, and Raman spectra are also discussed.

  11. Low-temperature synthesis of Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} with cubic garnet-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hui [Texas Materials Institute, ETC 9.184, University of Texas at Austin, Austin, TX 78712 (United States); Li, Yutao [Texas Materials Institute, ETC 9.184, University of Texas at Austin, Austin, TX 78712 (United States); State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Goodenough, John B., E-mail: jgoodenough@mail.utexas.edu [Texas Materials Institute, ETC 9.184, University of Texas at Austin, Austin, TX 78712 (United States)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer One-step synthesis and its optimization of cubic garnet Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} at 750 Degree-Sign C. Black-Right-Pointing-Pointer Instability above 800 Degree-Sign C of the Al-free cubic Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12}. Black-Right-Pointing-Pointer Li{sup +}-ion conductivity without adventitious Al{sup 3+}. -- Abstract: In this paper, we report the direct synthesis of Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} with the cubic garnet-type structure at low temperature with a lattice constant of 13.0035 Angstrom-Sign . The synthesis condition is optimized to be at 750 Degree-Sign C for 8 h with 30 wt% excess lithium salt. No intermediate grinding was involved in this straightforward route. Without the adventitious of Al{sup 3+}, the cubic Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} is unstable above 800 Degree-Sign C and has an ionic conductivity of the order of 10{sup -6} S cm{sup -1}.

  12. Ferroelectric properties and diffuse phase transition in (Pb,La)Zrsub(0.55)Tisub(0.45)O3 ceramics

    International Nuclear Information System (INIS)

    Wolters, M.

    1976-01-01

    A preparation technique for (Pb,La)Zrsub(0.55)Tisub(0.45)O 3 ceramics is described by which inhomogeneities are eliminated. Grain size effects are studied and ferroelectric-paraelectric phase-transitions are investigated by means of X-ray diffraction analysis and dielectric weak-field (permittivity) and high-field (dc bias and hysteresis) measurements

  13. Microstructures and mechanical properties of Gd{sub 2}Zr{sub 2}O{sub 7}/ZrO{sub 2}(3Y) ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Lei [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning 110819 (China); Key Laboratory for Advanced Ceramics and Application of Shenyang, Shenyang University of Chemical Technology, Shenyang, Liaoning 110142 (China); Ma, Weimin, E-mail: maleisy2003@163.com [Key Laboratory for Advanced Ceramics and Application of Shenyang, Shenyang University of Chemical Technology, Shenyang, Liaoning 110142 (China); Sun, Xudong, E-mail: xdsun@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang, Liaoning 110819 (China); Ji, Lianyong; Liu, Jianan; Hang, Kai [Key Laboratory for Advanced Ceramics and Application of Shenyang, Shenyang University of Chemical Technology, Shenyang, Liaoning 110142 (China)

    2015-09-25

    Highlights: • Gd{sub 2}Zr{sub 2}O{sub 7}/ZrO{sub 2}(3Y) composites were prepared using vacuum sintering. • The phase composition and microstructure are studied. • Gd{sub 2}Zr{sub 2}O{sub 7}/ZrO{sub 2}(3Y) materials show superior mechanical properties. • The solid solution strengthening and stress-induced phase transformation toughening mechanism are proposed. • Two kinds of mechanisms explain the improvement of mechanical properties. - Abstract: Gd{sub 2}Zr{sub 2}O{sub 7}/ZrO{sub 2}(3Y) composite ceramics were prepared by vacuum sintering using Gd{sub 2}Zr{sub 2}O{sub 7} and ZrO{sub 2}(3Y) nanoparticles. The ceramics were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), the three-point-bending technique and single-edge-notched-beam tests. The effect of various proportions of ZrO{sub 2}(3Y) on the phase composition, microstructure, bending strength and fracture toughness of the final Gd{sub 2}Zr{sub 2}O{sub 7}/ZrO{sub 2}(3Y) composite ceramics was also analyzed. The change from m-ZrO{sub 2} to t-ZrO{sub 2} phase contents, before and after fracture, was measured using XRD quantitative phase analysis. The results confirm that, with the increasing content of ZrO{sub 2}(3Y), a phase transition from solid solution to saturated precipitation occurs and the bending strength and fracture toughness of the samples increase gradually. When the content of ZrO{sub 2}(3Y) reached 95 vol.%, the Gd{sub 2}Zr{sub 2}O{sub 7}/ZrO{sub 2}(3Y) composite ceramics had a bending strength of 547 MPa and a fracture toughness of 5.5 MPa m{sup 1/2}, indicating that stress-induced phase transformation toughening was an efficient way to increase the mechanical properties of the Gd{sub 2}Zr{sub 2}O{sub 7} ceramics.

  14. Propertis of solidified radioactive wastes from commercial LWRs

    International Nuclear Information System (INIS)

    Neilson, R.M. Jr.; Colombo, P.

    1978-01-01

    A study has been performed to characterize the properties of solidified radioactive wastes generated in the liquid radwaste treatment systems at LWRs. The properties which have been studied are those which are pertinent in defining the relative potential for the release of radionuclides to the environment as well as others relating to the evaluation of various solidification agents on an economic and feasibility basis. The use of standard testing procedures in measuring these properties allows an intercomparison of respective properties between various types of solidified waste forms. The leachability, mechanical properties, thermal stability, radiation stability, and thermal properties of hydraulic cement, ureaformaldehyde, bitumen, and addition type polymer waste forms have been measured. In addition, the chemical sensitivity, volumetric efficiency and radiation shielding characteristics of these waste forms have been studied. Emphasis in this paper is placed on the results of studies concerning chemical compatibility of solidification agents with specific waste streams, volumetric efficiency, free standing water, and leachability

  15. Production and properties of solidified high-level waste

    International Nuclear Information System (INIS)

    Brodersen, K.

    1980-08-01

    Available information on production and properties of solidified high-level waste are presented. The review includes literature up to the end of 1979. The feasibility of production of various types of solidified high-level wast is investigated. The main emphasis is on borosilicate glass but other options are also mentioned. The expected long-term behaviour of the materials are discussed on the basis of available results from laboratory experiments. Examples of the use of the information in safety analysis of disposal in salt formations are given. The work has been made on behalf of the Danish utilities investigation of the possibilities of disposal of high-level waste in salt domes in Jutland. (author)

  16. Characterization of rapidly solidified powder of high-speed steel

    Czech Academy of Sciences Publication Activity Database

    Miglierini, M.; Lančok, Adriana; Kusý, M.

    2009-01-01

    Roč. 190, 1-3 (2009), s. 51-57 ISSN 0304-3843 R&D Projects: GA ČR GP203/07/P011 Grant - others:GA(SK) VEGA1/3190/06 Institutional research plan: CEZ:AV0Z40320502 Keywords : Rapidly solidified powder * Tool steel * Mössbauer spectroscopy Subject RIV: CA - Inorganic Chemistry Impact factor: 0.209, year: 2007

  17. Rapidly solidified prealloyed powders by laser spin atomization

    Science.gov (United States)

    Konitzer, D. G.; Walters, K. W.; Heiser, E. L.; Fraser, H. L.

    1984-01-01

    A new technique, termed laser spin atomization, for the production of rapidly solidified prealloyed powders is described. The results of experiments involving the production of powders of two alloys, one based on Ni, the other on Ti, are presented. The powders have been characterized using light optical metallography, scanning electron microscopy, energy dispersive X-ray spectroscopy, and Auger elec-tron spectroscopy, and these various observations are described.

  18. Crystallization of the amorphous Fe{sub 80}Zr{sub 12}B{sub 8} alloy under controlled heating

    Energy Technology Data Exchange (ETDEWEB)

    Huang, H. [School of Engineering (H6), University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Shao, G. [Centre for Materials Research and Innovation, University of Bolton, Bolton BL3 5AB (United Kingdom)], E-mail: G.Shao@bolton.ac.uk; Tsakiropoulos, P. [Department of Engineering Materials, Sir Robert Hadfirld Building, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

    2008-07-14

    The devitrification process of amorphous Fe{sub 80}Zr{sub 12}B{sub 8} alloy ribbons were studied under controlled thermal conditions. The major crystallization event during continuous heating with differential scanning calorimetory (DSC) is dictated by diffusion controlled growth and the associated atom mobility of the slow diffusing species Zr. The existence of prior nano-crystals formed by pre-annealing below the crystallization temperature had little effect on the major crystallization temperature. The crystallization sequence during heating was: amorphous {yields} amorphous + {alpha}-Fe + Fe{sub 3}Zr(B) {yields} amorphous + {alpha}-Fe + Fe{sub 3}Zr(B) + Fe{sub 2}Zr. Different from previous findings in alloys of lower Zr and B contents, the peak for the crystallization of the {alpha}-Fe phase alone is missing in the DSC traces of this alloy.

  19. Speciation of uranium in La{sub 2}Zr{sub 2}O{sub 7} pyrochlore by TRPLS

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, M.; Rajeswari, B.; Hon, N. S.; Kadam, R. M., E-mail: rmkadam@barc.gov.in; Natarajan, V. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)

    2015-06-24

    We discuss the speciation of uranium in lanthanum zirconate (La{sub 2}Zr{sub 2}O{sub 7} =LZO) pyrochlore ceramic prepared via a gel-combustion route. Uranium concentration in the pyrochlore was optimized to 2 mol%. XRD and SEM experiments were carried out to assess the phase and homogeneity of the prepared samples. Time resolved photoluminescence (TRPLS) investigations were carried out for understanding the species stabilized in the pyrochlore host. It was observed that, uranium exists as uranate ion (UO{sub 6}{sup 6−}) in the zirconate host where it replaces the ‘Zr’ ions at its regular site with surrounding defect centers created for charge compensation.

  20. Transformation of Ti/sub 30/Nb/sub 30/Zr/sub 7/Ta superconducting alloy

    Energy Technology Data Exchange (ETDEWEB)

    Horiuchi, T; Monju, Y; Tatara, I; Nagi, N

    1973-10-01

    The effect of cold working on the rates of beta phase decomposition in the Ti/sub 30/Nb/sub 30/Zr/sub 7/Ta superconducting alloy was investigated. T.T.T. diagrams for the cold worked specimen were determined from the changes in electrical resistivity at liquid nitrogen temperature, Micro vickers hardness number measurement and the lattice constants determined by the x-ray powder method. Some results are as follows: (1) the alpha phase precipitation occurs by ageing at temperatures higher than 550/sup 0/C. At 550/sup 0/C, the beta phase decomposition into the alpha-beta minutes + beta seconds phase temperatures higher than 550/sup 0/C. At 550/sup 0/C, the beta phase decomposition into the alpha minutes + beta + betaseconds phase was found. (2) the rates of the alpha phase precipitation were accelerated by cold working. (3) the omega phase precipitation was found between 450 and 700/sup 0/C. 17 references.

  1. Comparative study of local atomic structures in Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yuxiang [Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Huang, Li, E-mail: huangl@sustc.edu.cn [Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Wang, C. Z.; Ho, K. M. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Department of Physics, Iowa State University, Ames, Iowa 50011 (United States); Kramer, M. J. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

    2015-11-21

    Extensive analysis has been performed to understand the key structural motifs accounting for the difference in glass forming ability in the Zr-Cu and Zr-Ni binary alloy systems. Here, the reliable atomic structure models of Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) are constructed using the combination of X-ray diffraction experiments, ab initio molecular dynamics simulations and a constrained reverse Monte Carlo method. We observe a systematic variation of the interatomic distance of different atomic pairs with respect to the alloy composition. The ideal icosahedral content in all samples is limited, despite the high content of five-fold symmetry motifs. We also demonstrate that the population of Z-clusters in Zr{sub 2}Cu glass is much higher than that in the Zr{sub 2}Ni and Zr{sub 2}Cu{sub 0.5}Ni{sub 0.5} samples. And Z12 〈0, 0, 12, 0〉 Voronoi polyhedra clusters prefer to form around Cu atoms, while Ni-centered clusters are more like Z11 〈0, 2, 8, 1〉 clusters, which is less energetically stable compared to Z12 clusters. These two different structural properties may account for the higher glass forming ability of Zr{sub 2}Cu alloy than that of Zr{sub 2}Ni alloy.

  2. Cooling rate dependence of simulated Cu{sub 64.5}Zr{sub 35.5} metallic glass structure

    Energy Technology Data Exchange (ETDEWEB)

    Ryltsev, R. E. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); Ural Federal University, 19 Mira Str., 620002 Ekaterinburg (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Klumov, B. A. [L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Aix-Marseille-Université, CNRS, Laboratoire PIIM, UMR 7345, 13397 Marseille Cedex 20 (France); High Temperature Institute, Russian Academy of Sciences, 13/2 Izhorskaya Str., 125412 Moscow (Russian Federation); Chtchelkatchev, N. M. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 9 Institutskiy Per., Dolgoprudny, 141700 Moscow Region (Russian Federation); All-Russia Research Institute of Automatics, 22 Sushchevskaya, 127055 Moscow (Russian Federation); Shunyaev, K. Yu. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); Ural Federal University, 19 Mira Str., 620002 Ekaterinburg (Russian Federation)

    2016-07-21

    Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu{sub 64.5}Zr{sub 35.5} alloy during the cooling in a wide range of cooling rates γ ∈ (1.5 ⋅ 10{sup 9}, 10{sup 13}) K/s. Investigating short- and medium-range orders, we show that the structure of Cu{sub 64.5}Zr{sub 35.5} metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to an increase of abundances of both the icosahedral-like clusters and Frank-Kasper Z16 polyhedra. The amounts of these clusters in the glassy state drastically increase at the γ{sub min} = 1.5 ⋅ 10{sup 9} K/s. Analysing the structure of the glass at γ{sub min}, we observe the formation of nano-sized crystalline grain of Cu{sub 2}Zr intermetallic compound with the structure of Cu{sub 2}Mg Laves phase. The structure of this compound is isomorphous with that for Cu{sub 5}Zr intermetallic compound. Both crystal lattices consist of two types of clusters: Cu-centered 13-atom icosahedral-like cluster and Zr-centered 17-atom Frank-Kasper polyhedron Z16. That suggests the same structural motifs for the metallic glass and intermetallic compounds of Cu–Zr system and explains the drastic increase of the abundances of these clusters observed at γ{sub min}.

  3. Solidifier effectiveness : variation due to oil composition, oil thickness and temperature

    International Nuclear Information System (INIS)

    Fieldhouse, B.; Fingas, M.

    2009-01-01

    This paper provided an overview of solidifier types and composition. Solidifiers are a class of spill treating agents that offer an effective means to convert a liquid oil into a solid material. They are used as a treatment option for oil spills on water. This paper also reported on recent laboratory studies that consist of 4 components: (1) a qualitative examination of the characteristics of the interaction of a broad range of solidifier products with a standard oil to evaluate reaction rate, states of solidification, and the impact of dosage, (2) a comparison of a smaller subset of solidifiers on the standard oil at lower temperatures, (3) solidifier treatment on a range of oils of varying physical properties and composition to assess the potential scope of application, and (4) the treatment of a series of small-scale oil layers of varying thickness to determine the significance of oil thickness on solidifier effectiveness and recovery. This paper also reviewed solidifier chemistry with particular reference to polymer sorbents; cross-linking agents; and cross-linking agents and polymeric sorbents combined. Toxicity is also an important issue regarding solidifiers. The aquatic toxicity of solidifiers is low and not measurable as the products are not water-soluble. There have not been any studies on the effects of the solidifier or the treated oil on surface feeders and shoreline wildlife that may come into contact with the products. It was concluded that oil composition may play a major role in solidifier effectiveness. The effectiveness of solidifiers is also inhibited at reduced temperatures, increased viscosity and density of the oil. 25 refs., 5 tabs., 2 figs., 1 appendix

  4. Micro and Macro Segregation in Alloys Solidifying with Equiaxed Morphology

    Science.gov (United States)

    Stefanescu, Doru M.; Curreri, Peter A.; Leon-Torres, Jose; Sen, Subhayu

    1996-01-01

    To understand macro segregation formation in Al-Cu alloys, experiments were run under terrestrial gravity (1g) and under low gravity during parabolic flights (10(exp -2) g). Alloys of two different compositions (2% and 5% Cu) were solidified at two different cooling rates. Systematic microscopic and SEM observations produced microstructural and segregation maps for all samples. These maps may be used as benchmark experiments for validation of microstructure evolution and segregation models. As expected, the macro segregation maps are very complex. When segregation was measured along the central axis of the sample, the highest macro segregation for samples solidified at 1g was obtained for the lowest cooling rate. This behavior is attributed to the longer time available for natural convection and shrinkage flow to affect solute redistribution. In samples solidified under low-g, the highest macro-segregation was obtained at the highest cooling rate. In general, low-gravity solidification resulted in less segregation. To explain the experimental findings, an analytical (Flemings-Nereo) and a numerical model were used. For the numerical model, the continuum formulation was employed to describe the macroscopic transports of mass, energy, and momentum, associated with the microscopic transport phenomena, for a two-phase system. The model proposed considers that liquid flow is driven by thermal and solutal buoyancy, and by solidification shrinkage. The Flemings-Nereo model explains well macro segregation in the initial stages of low-gravity segregation. The numerical model can describe the complex macro segregation pattern and the differences between low- and high-gravity solidification.

  5. Nickel speciation in cement-stabilized/solidified metal treatment filtercakes

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Amitava, E-mail: reroy@lsu.edu [J. Bennett Johnston, Sr., Center for Advanced Microstructures and Devices, Louisiana State University, Baton Rouge, LA 70806, USA (United States); Stegemann, Julia A., E-mail: j.stegemann@ucl.ac.uk [Centre for Resource Efficiency & the Environment, Department of Civil, Environmental & Geomatic Engineering, University College London, Chadwick Building, Gower Street, London WC1E 6BT, UK (United Kingdom)

    2017-01-05

    Highlights: • XAS shows the same Ni speciation in untreated and stabilized/solidified filtercake. • Ni solubility is the same for untreated and stabilized/solidified filtercake. • Leaching is controlled by pH and physical encapsulation for all binders. - Abstract: Cement-based stabilization/solidification (S/S) is used to decrease environmental leaching of contaminants from industrial wastes. In this study, two industrial metal treatment filtercakes were characterized by X-ray diffractometry (XRD), thermogravimetric and differential thermogravimetric analysis (TG/DTG) and Fourier transform infrared (FTIR); speciation of nickel was examined by X-ray absorption (XAS) spectroscopy. Although the degree of carbonation and crystallinity of the two untreated filtercakes differed, α-nickel hydroxide was identified as the primary nickel-containing phase by XRD and nickel K edge XAS. XAS showed that the speciation of nickel in the filtercake was unaltered by treatment with any of five different S/S binder systems. Nickel leaching from the untreated filtercakes and all their stabilized/solidified products, as a function of pH in the acid neutralization capacity test, was essentially complete below pH ∼5, but was 3–4 orders of magnitude lower at pH 8–12. S/S does not respeciate nickel from metal treatment filtercakes and any reduction of nickel leaching by S/S is attributable to pH control and physical mechanisms only. pH-dependent leaching of Cr, Cu and Ni is similar for the wastes and s/s products, except that availability of Cr, Cu and Zn at decreased pH is reduced in matrices containing ground granulated blast furnace slag.

  6. Detection of free liquid in containers of solidified radioactive waste

    Science.gov (United States)

    Greenhalgh, W.O.

    Nondestructive detection of the presence of free liquid within a sealed enclosure containing solidified waste is accomplished by measuring the levels of waste at two diametrically opposite locations while slowly tilting the enclosure toward one of said locations. When the measured level remains constant at the other location, the measured level at said one location is noted and any measured difference of levels indicates the presence of liquid on the surface of the solifified waste. The absence of liquid in the enclosure is verified when the measured levels at both locations are equal.

  7. Undercooling and demixing in rapidly solidified Cu-Co alloys

    DEFF Research Database (Denmark)

    Battezzati, L.; Curiotto, S.; Johnson, Erik

    2007-01-01

    The Cu–Co system displays a metastable miscibility gap in the liquid state. A considerable amount of work has been performed to study phase separation and related microstructures showing that demixing of the liquid is followed by coagulation before dendritic solidification. Due to kinetic...... competition of transformation phenomena, the mechanisms have not been fully disclosed. This contribution reviews such findings with the help of a computer calculation of the phase diagram and extends the present knowledge by presenting new results obtained by rapidly solidifying various Cu–Co compositions...... using a wide range of cooling rates achieved by forcing the liquid into cylindric and conic moulds and by melt spinning....

  8. Filling of recovered mining areas using solidifying backfill

    Directory of Open Access Journals (Sweden)

    Zeman Róbert

    2001-12-01

    Full Text Available The aim of this article is to explore the possibilities for filling recovered mining areas using solidifying backfill .The article describes the preparation of the backfill (backfill formulation with an eventual application using low quality sands, wastes from treatment plants and ash from power plants etc now to transport it as well as its application in practice. Advantageous and disadvantageous of this method are also mentioned.Several factors must be taken info consideration during the preparation process of the backfill mixture. Firstly, the quantities of each individual component must be constantly regulated. Secondly, the properties of each component must be respected. In addition, the needs of the pipeline transport system and the specific conditions of the recovered area to be filled must also be considered.Hydraulic transport and pneumo-hydraulic pipeline transport are used for handling the backfill. Pumps for transporting the solidifying backfill have to carry out demanding tasks.Due to the physical-mechanical properties of the backfill, only highly powerful pumps can be considered. Piston type pumps such as Abel Simplex and Duplex pumps with capacities of up to 100 m3.h-1 and operating pressures of up to 16 MPa would be suitable.This method has been applied abroad for different purposes. For example, solid backfill was used in the Hamr mine during exploitation of uranium using the room-and-pillar system mining method.In the Ostrava–Karvina Coal field, backfill was used in decontamination work, filling areas in a zone of dangerous deformations and for creating a dividing stratum during thick seam mining.Research info the use of solidifying backfill was also done in the Walsum mine in Germany. The aim of this research was:- to investigate the possibilities of filling a collapsing area in a working face using a solidifying mixture of power plant ash and water,- to verify whether towing pipelines proposed by the DMT corporation would be

  9. Study on dissolution behavior of molten solidified waste

    International Nuclear Information System (INIS)

    Mizuno, Tsuyoshi; Maeda, Toshikatsu

    2005-01-01

    Radioactive molten solidified waste (slag) has been generated by melting non-metallic low-level radioactive wastes (LLW). Slag is expected to immobilize radionuclides in the waste repository. The chemical durability of slag is an important factor for the safety assessment of the disposal in that the durability provides the source term in the assessment. Since a chemical characteristic of slag is similar to that of glass, the general information on the chemical durability of slag might be provided from previous studies on nuclear waste glass. We have investigated effects of chemical compositions of slag and alkaline environments of repository on the chemical durability of slag. (author)

  10. Ordered perovskites with cationic vacancies. 7. Structural investigations on Ba/sub 2/Zrsub(3/4)vacantsub(1/4)SbO/sub 6/

    Energy Technology Data Exchange (ETDEWEB)

    Treiber, U; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

    1980-11-01

    The ochre coloured Ba/sub 2/Zrsub(3/4)vacantsub(1/4)SbO/sub 6/ belongs to the group of oxygen perovskites with an ordered distribution of the vacancies. It crystallizes tetragonal (a = 11.68/sub 5/ A; c = 16.60/sub 6/ A) with 16 formula units in the cell: Ba/sub 32/Zr/sub 12/vacant/sub 4/Sb/sub 16/O/sub 96/. For the space group P 4/mmm intensity calculations on powder data gave a refined, intensity related R' value of 4.8%. In the structure the Zr and Ba atoms are ordered (1:1 order); the four cationic vacancies are located in a face centered arrangement in the zirconium sublattice. The Ba atoms are displaced by approximately 0.20 A in direction of the neighbouring vacancy, while the other cations maintain their ideal positions.

  11. Permanent magnets prepared from Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0}N{sub y} without homogenization

    Energy Technology Data Exchange (ETDEWEB)

    Gebel, B.; Kubis, M.; Mueller, K.-H. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe

    1997-10-01

    In as-cast Sm{sub 2}Fe{sub 17} the high amount of {alpha}-Fe caused by a peritectic reaction can be considerably reduced by a small addition of about 1 at% Zr. X-ray diffraction showed that as-cast Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0} mainly consists of a phase with the Th{sub 2}Zn{sub 17}-type structure and SmFe{sub 3}. Non-homogenized Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0} was milled and (i) annealed in vacuum or (ii) treated with a hydrogenation-disproportionation-desorp tion-recombination (HDDR) process. The annealed and subsequently nitrogenated powder is magnetically anisotropic and has a coercivity {mu}{sub 0J}H{sub C} up to 2.0 T and an energy product (BH){sub max} up to 136 kJ/m{sup 3}. HDDR-treated and nitrogenated powder is isotropic and exhibits values of {mu}{sub 0J}H{sub C} = 3.1 T and (BH){sub max} 103 kJ/m{sup 3}. Consequently, Sm{sub 10.5}Fe{sub 88.5}Zr{sub 1.0}N{sub y} (y {approx} 16) permanent magnets with very good properties can be prepared without the time-consuming homogenization procedure. (orig.). 11 refs.

  12. Solidified ceramics of radioactive wastes and method of producing it

    International Nuclear Information System (INIS)

    Oota, Takao; Matake, Shigeru; Ooka, Kazuo.

    1980-01-01

    Purpose: To provide solidified ceramics which have low leaching properties to water of radioactive substance, excellent heat dissipating and resistive properties and high mechanical strength by mixing and sintering limited amounts of titanium and aluminum compounds with calcined radioactive wastes containing special compound. Method: More than 20% by weight of titanium compound (as TiO 2 ) and more than 5% by weight of aluminum compound (as Al 2 O 3 ) are mixed with the calcined radioactive wasted containing, as converted by oxide, 5 to 40% by weight of Na 2 O, 5 to 20% by weight of Fe 2 O 3 , 5 to 15% by weight of MoO 3 , 5 to 15% by weight of ZrO 2 , 2 to 10% by weight of CeO 2 , 2 to 10% by weight of Cs 2 O, 1 to 5% by weight of BaO, 1 to 5% by weight of SrO, 0.2 to 2% by weight of Rb 2 O, 0.2% by weight of Y 2 O 3 , 0.2 to 2% by weight of NiO, 5 to 20% by weight of rare earth metal oxide, and 0.2 to 2% by weight of Cr 2 O 3 . The mixture is molded, sintered, and solidified to ceramics which contains no Mo phase, Na 2 O, MoO 3 , K 2 O, MoO 3 and Cs 2 O, MoO 3 phases and the like. (Yoshino, Y.)

  13. Leaching experiment of cement solidified waste form under unsaturated condition

    International Nuclear Information System (INIS)

    Wang Zhiming; Yao Laigen; Li Shushen; Zhao Yingjie; Cai Yun; Li Dan; Han Xinsheng; An Yongfeng

    2003-01-01

    A device for unsaturated leaching experiments was designed and built up. 8 different sizes, ranging from 40.2 cm 3 to 16945.5 cm 3 , of solidified waste form were tested in the experiment. 5 different water contents, from 0.15 to 0.40, were used for the experiment. The results show that the cumulative leaching fraction increases with water content when the sizes of the forms are equal to and less than 4586.7 cm 3 , for example, the ratios of the cumulative leaching fractions are between 1.24-1.41 under water content of 0.35 and 0.15 on 360 day of Teaching. It can also be seen that the cumulative leaching fraction under higher water content is close to that under saturated condition. The cumulative leaching fraction decreases with size of the form. Maximum leached depth of the solidified waste forms is about 2.25 cm after one year Teaching. Moreover, it has no clear effect on cumulative leaching fraction that sampling or non-sampling during the experiment

  14. Vessel for solidifying water-impermeable radioactive waste

    International Nuclear Information System (INIS)

    Kiuchi, Yoshimasa; Tamada, Shin; Suzuki, Yasushi.

    1993-01-01

    A blend prepared by admixing silica sand, alumina powder or glass fiber, as aggregates, to epoxy resin elastic adhesives is coated on an inner surface of a steel drum can or an inner surface of a concrete vessel at a thickness of greater than 1mm followed by hardening. The addition amount of the silica sand, alumina powder or glass fiber is determined as 20 to 40% by weight, 30 to 60% by weight or 5 to 15% by weight respectively. A lid having a hole for injecting fillers is previously bonded to a container for use in solidifying radioactive materials. The strength of the coating layer is increased and a coating performance and an adhesion force are improved by admixing the aggregates, to provide a satisfactory water-impermeability. The container for use in solidifying radioactive wastes having a coating layer with an advantage of the elastic resin adhesives, strong strength and adhesion and being excellent in the water-impermeability can be obtained relatively economically. (N.H.)

  15. Self-irradiation effect on thermal conductivity of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N solid solution

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, Tsuyoshi, E-mail: tsuyoshi.nishi.75@vc.ibaraki.ac.jp [Department of Materials Science and Engineering, College of Engineering, Ibaraki University, Hitachi, Ibaraki, 316-8511 (Japan); Hayashi, Hirokazu; Sato, Takumi; Takano, Masahide [Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Tokai-mura, Ibaraki, 319-1195 (Japan)

    2017-04-01

    This study evaluated the dependence of the thermal conductivity of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N on storage time and temperature. The authors prepared sintered samples of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N solid solution and measured thermal diffusivity at storage times of 0, 24, 72, 144, 240, 408, 552, 816, 1,680, and 2064 h, from which it was determined that the thermal conductivity decreased exponentially with increasing storage time. This result suggests that the decrease of the thermal conductivity could be attributed to the accumulation of lattice defects from self-irradiation. To confirm the thermal recovery behavior of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N under annealing, thermal diffusivity was also measured just after annealing. The thermal conductivity of Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N was determined to be larger than that of Zr{sub 0.58}Pu{sub 0.21}Cm{sub 0.21}N but smaller than that of Zr{sub 0.80}Pu{sub 0.10}Cm{sub 0.10}N. - Highlights: •The authors prepared Zr{sub 0.70}Pu{sub 0.25}Cm{sub 0.05}N and measured thermal diffusivity. •Dependence of thermal conductivity on storage time was clarified. •After annealing at 1423 K in vacuum, thermal conductivity was recovered.

  16. Effects of leachate concentration on the integrity of solidified clay liners.

    Science.gov (United States)

    Xue, Qiang; Zhang, Qian

    2014-03-01

    This study aimed to evaluate the impact of landfill leachate concentration on the degradation behaviour of solidified clay liners and to propose a viable mechanism for the observed degradation. The results indicated that the unconfined compressive strength of the solidified clay decreased significantly, while the hydraulic conductivity increased with the leachate concentration. The large pore proportion in the solidified clay increased and the sum of medium and micro pore proportions decreased, demonstrating that the effect on the solidified clay was evident after the degradation caused by exposure to landfill leachate. The unconfined compressive strength of the solidified clay decreased with increasing leachate concentration as the leachate changed the compact structure of the solidified clay, which are prone to deformation and fracture. The hydraulic conductivity and the large pore proportion of the solidified clay increased with the increase in leachate concentration. In contrast, the sum of medium and micro pore proportions showed an opposite trend in relation to leachate concentration, because the leachate gradually caused the medium and micro pores to form larger pores. Notably, higher leachate concentrations resulted in a much more distinctive variation in pore proportions. The hydraulic conductivity of the solidified clay was closely related to the size, distribution, and connection of pores. The proportion of the large pores showed a positive correlation with the increase of hydraulic conductivity, while the sum of the proportions of medium and micro pores showed a negative correlation.

  17. Chemical leaching of rapidly solidified Al-Si binary alloys

    International Nuclear Information System (INIS)

    Yamauchi, I.; Takahara, K.; Tanaka, T.; Matsubara, K.

    2005-01-01

    Various particulate precursors of Al 100-x Si x (x = 5-12) alloys were prepared by a rapid solidification process. The rapidly solidified structures of the precursors were examined by XRD, DSC and SEM. Most of Si atoms were dissolved into the α-Al(fcc) phase by rapid solidification though the solubility of Si in the α-Al phase is negligibly small in conventional solidification. In the case of 5 at.% Si alloy, a single α-Al phase was only formed. The amount of the primary Si phase increased with increase of Si content for the alloys beyond 8 at.% Si. Rapid solidification was effective to form super-saturated α-Al precursors. These precursors were chemically leached by using a basic solution (NaOH) or a hydrochloric acid (HCl) solution. All Al atoms were removed by a HCl solution as well as a NaOH solution. Granules of the Si phase were newly formed during leaching. The specific surface area was about 50-70 m 2 /g independent of Si content. The leaching behavior in both solutions was slightly different. In the case of a NaOH solution, the shape of the precursor often degenerated after leaching. On the other hand, it was retained after leaching by a HCl solution. Fine Si particles precipitated in the α-Al phase by annealing of as-rapidly solidified precursors at 773 K for 7.2 x 10 3 s. In this case, it was difficult to obtain any products by NaOH leaching, but a few of Si particles were obtained by HCl leaching. Precipitated Si particles were dissolved by the NaOH solution. The X-ray diffraction patterns of leached specimens showed broad lines of the Si phase and its lattice constant was slightly larger than that of the pure Si phase. The microstructures of the leached specimens were examined by transmission electron microscopy. It showed that the leached specimens had a skeletal structure composed of slightly elongated particles of the Si phase and quite fine pores. The particle size was about 30-50 nm. It was of comparable order with that evaluated by Scherer

  18. Synthesis of nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} by absorption of ammonia into water-in-oil microemulsion in a rotor–stator reactor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yingwen; Wang, Hongrun; Arowo, Moses; Sun, Baochang, E-mail: sunbc@mail.buct.edu.cn; Chen, Jianfeng; Shao, Lei, E-mail: shaol@mail.buct.edu.cn [Beijing University of Chemical Technology, State Key Laboratory of Organic–Inorganic Composites (China)

    2015-01-15

    A gas-microemulsion reaction precipitation method was employed to prepare nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} by absorption of NH{sub 3} into water-in-oil (W/O) microemulsion in a rotor–stator reactor . The effects of different operating conditions including final pH of the microemulsion, reaction temperature, initial Ce{sup 3+} and Zr{sup 4+} concentration, rotation speed, and gas–liquid volumetric ratio were investigated. Nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} with an average diameter of about 5.5 nm, a specific surface area of 215.6 m{sup 2}/g and a size distribution of 4–8 nm was obtained under the optimum operating conditions. The as-prepared nano-Ce{sub 0.5}Zr{sub 0.5}O{sub 2} was loaded with Au to prepare nano-Au/Ce{sub 0.5}Zr{sub 0.5}O{sub 2} catalyst which was subsequently used for CO oxidation test. CO conversion rate reached 100 % at room temperature, indicating high catalytic activity of the nano-Au/Ce{sub 0.5}Zr{sub 0.5}O{sub 2} catalyst.

  19. Epitaxial thin-film growth of Ruddlesden-Popper-type Ba{sub 3}Zr{sub 2}O{sub 7} from a BaZrO{sub 3} target by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Shariqa Hassan; Rafique, M.S.; Siraj, K.; Latif, A.; Afzal, Amina [University of Engineering and Technology, Laser and Optronics Centre, Department of Physics, Lahore (Pakistan); Awan, M.S. [Ibn-e-Sina Institute of Science and Technology (ISIT), Islamabad (Pakistan); Bashir, Shazia [Government College University, Centre for Advanced Studies in Physics, Lahore (Pakistan); Iqbal, Nida [Universiti Teknologi Malaysia, Medical Devices and Technology Group (MEDITEG), Faculty of Biosciences and Medical Engineering, Johor Bahru, Johor (Malaysia)

    2016-07-15

    Ruddlesden-Popper Ba{sub 3}Zr{sub 2}O{sub 7} thin films have been synthesized via pulsed laser deposition (PLD) technique. The optimization of deposition parameters in PLD enables the formation of thin film of metastable Ba{sub 3}Zr{sub 2}O{sub 7} phase from BaZrO{sub 3} target. In order to see the post-annealing effects on the structural and optical properties, the deposited Ba{sub 3}Zr{sub 2}O{sub 7} thin films were annealed at 500, 600 and 800 C. X-ray diffraction (XRD) reveals the formation of Ba{sub 3}Zr{sub 2}O{sub 7} phase with tetragonal structure. The changes in the surface of the deposited films were analysed by FE-SEM and AFM. The thin film post-annealed at 500 C exhibited the best structural, optical and surface properties. Furthermore, the chemical states and chemical composition of the films were determined by X-ray photoelectron spectroscopy (XPS) near the surface. The XPS results show that Ba, Zr and O exist mainly in the form of Ba{sub 3}Zr{sub 2}O{sub 7} Ruddlesden-Popper-type perovskite structure. (orig.)

  20. Experiment of solidifying photo sensitive polymer by using UV LED

    Science.gov (United States)

    Kang, Byoung Hun; Shin, Sung Yeol

    2008-11-01

    The development of Nano/Micro manufacturing technologies is growing rapidly and in the same manner, the investments in these areas are increasing. The applications of Nano/Micro technologies are spreading out to semiconductor production technology, biotechnology, environmental engineering, chemical engineering and aerospace. Especially, SLA is one of the most popular applications which is to manufacture 3D shaped microstructure by using UV laser and photo sensitive polymer. To make a high accuracy and precision shape of microstructures that are required from the diverse industrial fields, the information of interaction relationship between the photo resin and the light source is necessary for further research. Experiment of solidifying photo sensitive polymer by using UV LED is the topic of this paper and the purpose of this study is to find out what relationships do the reaction of the resin have in various wavelength, power of the light and time.

  1. Effective hydrogen diffusion coefficient for solidifying aluminium alloys

    International Nuclear Information System (INIS)

    Felberbaum, M.; Landry-Desy, E.; Weber, L.; Rappaz, M.

    2011-01-01

    An effective hydrogen diffusion coefficient has been calculated for two solidifying Al - 4.5 wt.% Cu and Al - 10 wt.% Cu alloys as a function of the volume fraction of solid. For this purpose, in situ X-ray tomography was performed on these alloys. For each volume fraction of solid between 0.6 and 0.9, a representative volume element of the microstructure was extracted. Solid and liquid voxels were assimilated to solid and liquid nodes in order to solve the hydrogen diffusion equation based on the chemical potential and using a finite volume formulation. An effective hydrogen diffusion coefficient based on the volume fraction of solid only could be deduced from the results of the numerical model at steady state. The results are compared with various effective medium theories.

  2. Microstructural Quantification of Rapidly Solidified Undercooled D2 Tool Steel

    Science.gov (United States)

    Valloton, J.; Herlach, D. M.; Henein, H.; Sediako, D.

    2017-10-01

    Rapid solidification of D2 tool steel is investigated experimentally using electromagnetic levitation (EML) under terrestrial and reduced gravity conditions and impulse atomization (IA), a drop tube type of apparatus. IA produces powders 300 to 1400 μm in size. This allows the investigation of a large range of cooling rates ( 100 to 10,000 K/s) with a single experiment. On the other hand, EML allows direct measurements of the thermal history, including primary and eutectic nucleation undercoolings, for samples 6 to 7 mm in diameter. The final microstructures at room temperature consist of retained supersaturated austenite surrounded by eutectic of austenite and M7C3 carbides. Rapid solidification effectively suppresses the formation of ferrite in IA, while a small amount of ferrite is detected in EML samples. High primary phase undercoolings and high cooling rates tend to refine the microstructure, which results in a better dispersion of the eutectic carbides. Evaluation of the cell spacing in EML and IA samples shows that the scale of the final microstructure is mainly governed by coarsening. Electron backscattered diffraction (EBSD) analysis of IA samples reveals that IA powders are polycrystalline, regardless of the solidification conditions. EBSD on EML samples reveals strong differences between the microstructure of droplets solidified on the ground and in microgravity conditions. While the former ones are polycrystalline with many different grains, the EML sample solidified in microgravity shows a strong texture with few much larger grains having twinning relationships. This indicates that fluid flow has a strong influence on grain refinement in this system.

  3. Structure fields in the solidifying cast iron roll

    Directory of Open Access Journals (Sweden)

    W.S. Wołczyński

    2010-01-01

    Full Text Available Some properties of the rolls depend on the ratio of columnar structure area to equiaxed structure area created during roll solidification. The transition is fundamental phenomenon that can be apply to characterize massive cast iron rolls produced by the casting house. As the first step of simulation, a temperature field for solidifying cast iron roll was created. The convection in the liquid is not comprised since in the first approximation, the convection does not influence the studied occurrence of the (columnar to equiaxed grains transition in the roll. The obtained temperature field allows to study the dynamics of its behavior observed in the middle of the mould thickness. This midpoint of the mould thickness was treated as an operating point for the transition. A full accumulation of the heat in the mould was postulated for the transition. Thus, a plateau at the curve was observed at the midpoint. The range of the plateau existence corresponded to the incubation period , that appeared before fully equiaxed grains formation. At the second step of simulation, behavior of the thermal gradients field was studied. Three ranges within the filed were visible: EC→EC→EC→EC→(tTECtt↔RERCtt↔a/ for the formation of columnar structure (the C – zone: ( and 0>>T&0>>=−>−=REREttGttG.The columnar structure formation was significantly slowed down during incubation period. It resulted from a competition between columnar growth and equiaxed growth expected at that period of time. The 0≈=−=RERCttGttG relationship was postulated to correspond well with the critical thermal gradient, known in the Hunt’s theory. A simulation was performed for the cast iron rolls solidifying as if in industrial condition. Since the incubation divides the roll into two zones: C and E; (the first with columnar structure and the second with fully equiaxed structure some experiments dealing with solidification were made on semi-industrial scale.

  4. Effect of twins in Ni substrates on the microstructure of La{sub 2}Zr{sub 2}O{sub 7} films for coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Sarah [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Pairis, Sébastien [Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Mikolajczyk, Mélissa [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Ortega, Luc [Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Soubeyroux, Jean-Louis [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Odier, Philippe [CRETA-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France); Institut Néel-CNRS, 25 av. des Martyrs, BP166, 38042 Grenoble Cedex (France)

    2013-03-01

    La{sub 2}Zr{sub 2}O{sub 7} (LZO) films were deposited by chemical solution deposition on Ni{sub 95}Wi{sub 5}rolling assisted bi-axially textured substrates to be used in YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) coated conductors. These LZO films were proved of good qualities for YBCO deposition by metal organic chemical vapor deposition that is an economic process. The mosaic of LZO films is only slightly degraded by the process of grain-to-grain epitaxial transfer (16% with respect to that of the substrate). The film is composed of small crystallites (20–40 nm) and larger anomalous crystallites (100–400 nm) found in great number in transferred twins from the substrate. The anomalous crystallites are poorly crystallized or amorphous and contain more C than areas with normal crystallites. High temperature in-situ X-ray diffraction shows a sudden crystallization at 860 °C that does not seem to involve a solid state reaction. The anomalous crystallites are analyzed to result from a locally enhanced barrier to nucleation and might reveal poor characteristics of the crystallization. - Highlights: ► La{sub 2}Zr{sub 2}O{sub 7} film on Ni{sub 95}W{sub 5} RABiT. ► Anomalous crystallites (100-400 nm) are amorphous on transferred twins. ► La{sub 2}Zr{sub 2}O{sub 7} crystallization appears above 860 °C.

  5. Electric quadrupole and magnetic dipole interactions at {sup 181}Ta impurity in Zr{sub 2}Ni{sub 7} intermetallic compound: Experiment and first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Dey, C.C., E-mail: chandicharan.dey@saha.ac.in [Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700064 (India); Srivastava, S.K. [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India)

    2013-10-15

    Electric quadrupole interactions at {sup 181}Ta impurity in the intermetallic compound Zr{sub 2}Ni{sub 7} have been studied by perturbed angular correlation technique. It has been found that there are two electric field gradients (EFG) at the {sup 181}Ta site due to two different crystalline configurations in Zr{sub 2}Ni{sub 7}, while contradictory results were reported from previous investigations. The values of EFG at room temperature have been found to be V{sub zz}=7.9×10{sup 17} V/cm{sup 2} and 7.1×10{sup 17} V/cm{sup 2} corresponding to present experimental values of quadrupole frequencies and asymmetry parameters for the two sites: ω{sub Q}{sup 1}=70.7(1) Mrad/s, η=0.28(1), δ=0.8(2)% (site fraction 84%) and ω{sub Q}{sup 2}=63(1) Mrad/s, η=0.35(5), δ∼0 (site fraction 9%). Electric field gradients and asymmetry parameters have been computed from the complementary first-principles density functional theory (DFT) to compare with present experimental results. Our calculated values of EFG are found to be in close agreement with the experimental results. No magnetic interactions in Zr{sub 2}Ni{sub 7} have been observed at 298 and 77 K which implies that there is no ferromagnetic ordering in this material down to 77 K. This observation is corroborated by theoretical calculations, wherein no magnetic moment or hyperfine field is found at any atomic site.

  6. Solidified structure of Al-Pb-Cu alloys

    International Nuclear Information System (INIS)

    Ikeda, Tetsuyuki; Nishi, Seiki; Kumeuchi, Hiroyuki; Tatsuta, Yoshinori.

    1986-01-01

    Al-Pb-Cu alloys were cast into bars or plates in different two metal mold casting processes in order to suppress gravity segregation of Pb and to achieve homogeneous dispersion of Pb phase in the alloys. Solidified structures were analyzed by a video-pattern-analyzer. Plate castings 15 to 20 mm in thickness of Al-Pb-1 % Cu alloy containing Pb up to 5 % in which Pb phase particles up to 10 μm disperse are achieved through water cooled metal mold casting. The plates up to 5 mm in thickness containing Pb as much as 8 to 10 % cast in this process have dispersed Pb particles up to 5 μm in diameter in the surface layer. Al-8 % Pb-1 % Cu alloy bars 40 mm in diameter and 180 mm in height in which gravity segregation of Pb is prevented can be cast by movable and water sprayed metal mold casting at casting temperature 920 deg C and mold moving speed 1.0 mm/s. Pb phase particles 10 μm in mean size are dispersed in the bars. (author)

  7. Characteristics of solidified products containing radioactive molten salt waste.

    Science.gov (United States)

    Park, Hwan-Seo; Kim, In-Tae; Cho, Yong-Zun; Eun, Hee-Chul; Kim, Joon-Hyung

    2007-11-01

    The molten salt waste from a pyroprocess to recover uranium and transuranic elements is one of the problematic radioactive wastes to be solidified into a durable wasteform for its final disposal. By using a novel method, named as the GRSS (gel-route stabilization/solidification) method, a molten salt waste was treated to produce a unique wasteform. A borosilicate glass as a chemical binder dissolves the silicate compounds in the gel products to produce one amorphous phase while most of the phosphates are encapsulated by the vitrified phase. Also, Cs in the gel product is preferentially situated in the silicate phase, and it is vitrified into a glassy phase after a heat treatment. The Sr-containing phase is mainly phosphate compounds and encapsulated by the glassy phase. These phenomena could be identified by the static and dynamic leaching test that revealed a high leach resistance of radionuclides. The leach rates were about 10(-3) - 10(-2) g/m2 x day for Cs and 10(-4) - 10(-3) g/m2 x day for Sr, and the leached fractions of them were predicted to be 0.89% and 0.39% at 900 days, respectively. This paper describes the characteristics of a unique wasteform containing a molten salt waste and provides important information on a newly developed immobilization technology for salt wastes, the GRSS method.

  8. Site suitability criteria for solidified high level waste repositories

    International Nuclear Information System (INIS)

    Heckman, R.A.; Holdsworth, T.; Isherwood, D.; Towse, D.F.; Dayem, N.L.

    1979-01-01

    The NRC is developing a framework of regulations, criteria, and standards. Lawrence Livermore Laboratory provides broad technical support to the NRC for developing this regulatory framework, part of which involves site suitability criteria for solidified high-level wastes (SHLW). Both the regulatory framework and the technical base on which it rests have evolved in time. This document is the second report of the technical support project. It was issued as a draft working paper for a programmatic review held at LLL from August 16 to 18, 1977. It was printed and distributed solely as a briefing document on preliminary methodology and initial findings for the purpose of critical review by those in attendance. These briefing documents are being reprinted now in their original formats as UCID-series reports for the sake of the historical record. Analysis results have evolved as both the models and data base have changed. As a result, the methodology, models, and data base in this document are severely outmoded

  9. A new technology for concentrating and solidifying liquid LLRW

    Energy Technology Data Exchange (ETDEWEB)

    Newell, N. [TMC, Inc., Portland, OR (United States); Osborn, M.W.; Carey, C.C. [Oregon Health Sciences Univ., Portland, OR (United States)] [and others

    1995-12-31

    One of the unsolved problem areas of low level radioactive waste management is the radiolabeled material generated by life sciences research and clinical diagnostics. In hundreds of academic, biotechnology, and pharmaceutical institutions, there exists large amounts of both aqueous and organic solutions containing radioactively labeled nucleic acids, proteins, peptides, and their monomeric components. We have invented a generic slurry capable of binding all these compounds, thus making it possible to concentrate and solidify the radioactive molecules into a very small and lightweight material. The slurry can be contained in both large and small disposal plastic devices designed for the size of any particular operation. The savings in disposal costs and convenience of this procedure is a very attractive alternative to the present methods of long and short term storage. Additionally, the slurry can remove radiolabeled biological compounds from organic solvents, thus solving the major problem of {open_quotes}mixed{close_quotes} waste. We are now proceeding with the field application stage for the testing of these devices and anticipate widespread use of the process. We also are exploring the use of the slurry on other types of liquid low level radioactive waste.

  10. Solidified self-nanoemulsifying formulation for oral delivery of combinatorial therapeutic regimen

    DEFF Research Database (Denmark)

    Jain, Amit K; Thanki, Kaushik; Jain, Sanyog

    2014-01-01

    PURPOSE: The present work reports rationalized development and characterization of solidified self-nanoemulsifying drug delivery system for oral delivery of combinatorial (tamoxifen and quercetin) therapeutic regimen. METHODS: Suitable oil for the preparation of liquid SNEDDS was selected based...

  11. Welding and Weldability of Directionally Solidified Single Crystal Nickel-Base Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Vitek, J M; David, S A; Reed, R W; Burke, M A; Fitzgerald, T J

    1997-09-01

    Nickel-base superalloys are used extensively in high-temperature service applications, and in particular, in components of turbine engines. To improve high-temperature creep properties, these alloys are often used in the directionally-solidified or single-crystal form. The objective of this CRADA project was to investigate the weldability of both experimental and commercial nickel-base superalloys in polycrystalline, directionally-solidified, and single-crystal forms.

  12. Apatite layer growth on glassy Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} sputtered titanium for potential biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Thanka Rajan, S.; Karthika, M. [Electrochemical Materials Science Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630003 (India); Bendavid, Avi [Plasma Processing & Deposition Team, CSIRO Manufacturing Flagship, LindField, 2070, Sydney (Australia); Subramanian, B., E-mail: subramanianb3@gmail.com [Plasma Processing & Deposition Team, CSIRO Manufacturing Flagship, LindField, 2070, Sydney (Australia); Electrochemical Materials Science Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630003 (India)

    2016-04-30

    Graphical abstract: - Highlights: • Metallic biomaterials are surface modified by Zr based TFMGs. • A bone-like apatite layer was grown on a Ni-free Zr-based TFMG in vitro. • Apatite layer growth confirmed by XRD and XPS analysis indicates its bioactivity. • Electrochemical response of the TFMGs in SBF possesses good corrosion resistance. - Abstract: The bioactivity of magnetron sputtered thin film metallic glasses (TFMGs) of Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} (at.%) on titanium substrates was tested for bio implant applications. The structural and elemental compositions of TFMGs were analyzed by XRD, XPS and EDAX. X-ray diffraction analysis displayed a broad hump around the incident angle of 30–50°, suggesting that the coatings possess a glassy structure. An in situ crystal growth of hydroxyapatite was observed by soaking the sputtered specimen in simulated body fluid (SBF). The nucleation and growth of a calcium phosphate (Ca–P) bone-like hydroxyapatite on Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} (at.%) TFMG from SBF was investigated by using XRD, AFM and SEM. The presence of calcium and phosphorus elements was confirmed by EDAX and XPS. In vitro electrochemical corrosion studies indicated that the Zr-based TFMG coating sustain in the stimulated body-fluid (SBF), exhibiting superior corrosion resistance with a lower corrosion penetration rate and electrochemical stability than the bare crystalline titanium substrate.

  13. Ab initio molecular dynamics study of lithium diffusion in tetragonal Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Andriyevsky, B., E-mail: bohdan.andriyevskyy@tu.koszalin.pl [Faculty of Electronics and Computer Sciences, Koszalin University of Technology, 2 Śniadeckich Str., PL-75-453, Koszalin (Poland); Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, D-89069, Ulm (Germany); Doll, K. [Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, D-89069, Ulm (Germany); Institute of Theoretical Chemistry, Pfaffenwaldring 55, D-70569, Stuttgart (Germany); Jacob, T. [Institute of Electrochemistry, Ulm University, Albert-Einstein-Allee 47, D-89069, Ulm (Germany); Helmholtz Institute Ulm (HIU) for Electrochemical Energy Storage, Albert-Einstein-Allee 11, D-89081, Ulm (Germany)

    2017-01-01

    Using ab initio density functional theory the thermally-stimulated migration of lithium ions in the garnet-type material Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} is investigated. The methods of ab initio molecular dynamics have been applied to calculate the lithium ion self-diffusion coefficient and the diffusion barriers as function of lithium ion concentration. The concentration of lithium in the initial Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} crystal unit cell is varied from 53 to 59 atoms, where 56 lithium atoms represent the stoichiometric concentration. Almost monotonous dependencies of the main characteristics on the number of lithium atoms N{sup (Li)} have been found, except for a non-monotonous peculiarity of the stoichiometric compound (N{sup (Li)} = 56). Finally, the influence of the unit cell volume change on lithium ion diffusion parameters as well as lithium ion hopping rates has been studied. - Highlights: • Partial lithium atoms subtraction from LLZO increases diffusion coefficient D{sup (Li)}. • Partial subtraction of lithium atoms from LLZO decreases activation energy E{sub a}{sup (Li)}. • Activation energy E{sub a}{sup (Li)} is the smallest for tetrahedral oxygen surrounding. • Compression of LLZO leads to a decrease of lithium ion diffusion coefficient D{sup (Li)}.

  14. Mechanical spectroscopy study on the Cu{sub 54}Zr{sub 40}Al{sub 6} amorphous matrix alloy at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Marques, P.W.B., E-mail: paulowilmar@df.ufscar.br [Departamento de Física, Universidade Federal de São Carlos, CP-676, São Carlos, SP (Brazil); Chaves, J.M.; Silva, P.S.; Florêncio, O. [Departamento de Física, Universidade Federal de São Carlos, CP-676, São Carlos, SP (Brazil); Moreno-Gobbi, A. [Instituto de Física, Facultad de Ciencias (UDELAR), Iguá 4225, CEP 11400 Montevideo (Uruguay); Aliaga, L.C.R.; Botta, W.J. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, CP-676, São Carlos, SP (Brazil)

    2015-02-05

    Highlights: • Cu{sub 54}Zr{sub 40}Al{sub 6} alloy was characterized by mechanical spectroscopy at low temperature. • Flexural and ultrasonic methods showed peaks associated to rearrangement of clusters. • The peaks less stable were associated with annihilation of Zr or Cu clusters. • MHz range can be favors the formation of Cu an Al-centered icosahedral structures. • TEM images show an increase in the size and number of crystal in amorphous matrix. - Abstract: A mechanical spectroscopy study of Cu{sub 54}Zr{sub 40}Al{sub 6} bulk metallic glasses composites was carried out in the kHz and MHz frequency ranges, by means of flexural and ultrasonic methods, respectively, in the temperature interval 150–300 K. In internal friction and attenuation curves at low temperature were observed peaks which were associated with distortions in the configuration of atomic clusters, which absorbed different quantities of energy due to short and medium order rearrangements. Changes within the clusters or atomic jumps between clusters occurring in the specimen induced the onset of polyamorphic peaks, since electronic interactions and bonding changed abruptly.

  15. Structural and magnetic evolution of nanostructured Co{sub 40}Fe{sub 10}Zr{sub 10}B{sub 40} prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Raanaei, Hossein, E-mail: hraanaei@yahoo.com [Department of Physics, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Abbasi, Sadeq [Department of Physics, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Behaein, Saeed [Department of Physics, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

    2015-06-15

    The structural and magnetic properties of nanocrystalline alloy powder Co{sub 40}Fe{sub 10}Zr{sub 10}B{sub 40} prepared by mechanical alloying have been characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM) and differential scanning calorimeter (DSC). It is shown that the crystallite size has been decreased significantly to about 15 nm after 8 h milling time. On continuing the milling time mechanical crystallization and subsequently the alloying process were noticed up to 190 h. Saturation magnetization decreased during the whole process while coercivity achieved the highest value at the crystallization stage. Post treatment of milled powder at 190 h revealed crystalline constituent elements. - Highlights: • This article focuses on mechanical alloying of Co{sub 40}Fe{sub 10}Zr{sub 10}B{sub 40} system. • Mechanical crystallization is observed. • Structural and magnetic properties were investigated. • The heat treatment revealed the crystalline phases of constituent elements.

  16. Characterization and luminescent properties of Eu{sup 3+} doped Gd{sub 2}Zr{sub 2}O{sub 7} nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Rabasovic, M.S., E-mail: majap@ipb.ac.rs [Institute of Physics, University of Belgrade (Serbia); Sevic, D. [Institute of Physics, University of Belgrade (Serbia); Krizan, J. [Faculty for Mechanical Engineering, University of Ljubljana (Slovenia); Terzic, M. [Faculty of Science, University of Novi Sad (Serbia); Mozina, J. [Faculty for Mechanical Engineering, University of Ljubljana (Slovenia); Marinkovic, B.P.; Savic-Sevic, S. [Institute of Physics, University of Belgrade (Serbia); Mitric, M. [Vinča Institute of Nuclear Science, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Rabasovic, M.D.; Romcevic, N. [Institute of Physics, University of Belgrade (Serbia)

    2015-02-15

    Highlights: • Nanopowders Gd{sub 2}Zr{sub 2}O{sub 7} doped by europium ions (Eu{sup 3+}) have been synthesized. • Their luminescence properties have been measured at room temperature. • The temporal evolution of laser induced phenomena are presented using time-resolved technique. • Lifetime analysis for luminescence bands in emission spectra has been done. - Abstract: Nanopowders based on gadolinium zirconium oxide (Gd{sub 2}Zr{sub 2}O{sub 7}) doped by europium ions (Eu{sup 3+}) were successfully prepared using a flame combustion method. This material is suitable for various optical devices. The structure of prepared materials has been confirmed and characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes by using the streak camera system. PL spectra were obtained at three different excitation wavelengths (Optical Parametric Oscilator (OPO) at 360 nm, laser diode at 365 nm and Ar laser line at 514.5 nm). The strong emission lines at 611 nm and 630 nm corresponding to the {sup 5}D{sub 0} → {sup 7}F{sub 2} long lived transition could be used as a new red light source in optical devices.

  17. Containment of solidified liquid hazardous waste in domal salt

    International Nuclear Information System (INIS)

    Domenico, P.A.; Lerman, A.

    1992-01-01

    In recent years, the solidification of hazardous liquid waste has become a viable option in waste management. The solidification process results in an increased volume but more stable waste form that must be disposed of or stored in a dry environment. An environment of choice in south central Texas is domal salt. The salt dome currently under investigation has a water content of 0.002 percent by weight and a permeability less than one nanodarcy. A question that must be addressed is whether a salt dome has a particular set of attributes that will prevent the release of contaminants to the environment. From a regulatory perspective, a ''no migration'' petition must be approved by the U.S.E.P.A. for the containment facility. By ''no migration'' it is implied that the waste must be contained for 10,000 years. A demonstration that this condition will be met will require model calculations and such models must be based on the physical and chemical characteristics of the waste form and the geologic environment. In particular, the models must address the rate of brine infiltration into the caverns, providing information on how fast an immobile solid waste form could convert to a more mobile liquid state. Additionally, the potential for migration by both diffusion and advection is of concern. Lastly, given a partially saturated cavern, the question of how far gaseous waste will be transported over the 10,000 year containment period must also be addressed. Results indicate that the containment capabilities of domal salt are exceptional. A nominal volume of brine will seep into the cavern and most voids between the injected solidified waste pellets will remain unsaturated. Very small quantities of hazardous constituents will be leached from the waste pellets

  18. Measurements of Mercury Released from Solidified/Stabilized Waste Forms

    International Nuclear Information System (INIS)

    Mattus, C.H.

    2001-01-01

    This report covers work performed during FY 1999-2000 in support of treatment demonstrations conducted for the Mercury Working Group of the U.S. Department of Energy (DOE) Mixed Waste Focus Area. In order to comply with the requirements of the Resource Conservation and Recovery Act, as implemented by the U.S. Environmental Protection Agency (EPA), DOE must use one of these procedures for wastes containing mercury at levels above 260 ppm: a retorting/roasting treatment or an incineration treatment (if the wastes also contain organics). The recovered radioactively contaminated mercury must then be treated by an amalgamation process prior to disposal. The DOE Mixed Waste Focus Area and Mercury Working Group are working with the EPA to determine if some alternative processes could treat these types of waste directly, thereby avoiding for DOE the costly recovery step. They sponsored a demonstration in which commercial vendors applied their technologies for the treatment of two contaminated waste soils from Brookhaven National Laboratory. Each soil was contaminated with ∼4500 ppm mercury; however, one soil had as a major radioelement americium-241, while the other contained mostly europium-152. The project described in this report addressed the need for data on the mercury vapor released by the solidified/stabilized mixed low-level mercury wastes generated during these demonstrations as well as the comparison between the untreated and treated soils. A related work began in FY 1998, with the measurement of the mercury released by amalgamated mercury, and the results were reported in ORNL/TM-13728. Four treatments were performed on these soils. The baseline was obtained by thermal treatment performed by SepraDyne Corp., and three forms of solidification/stabilization were employed: one using sulfur polymer cement (Brookhaven National Laboratory), one using portland cement [Allied Technology Group (ATG)], and a third using proprietary additives (Nuclear Fuel Services)

  19. Amorphization and crystallization of Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) alloys during mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yan [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, 73 Jingshi Road, Jinan 250061 (China); School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China); Chen Xiuxiu [School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China); Geng Haoran [School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China)], E-mail: mse_wangy@ujn.edu.cn; Yang Zhongxi [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, 73 Jingshi Road, Jinan 250061 (China); School of Materials Science and Engineering, University of Jinan, 106 Jiwei Road, Jinan 250022 (China)

    2009-04-17

    In the present paper, the effect of Nb and different rotation speeds on the amorphization and crystallization of Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) alloys during mechanical alloying has been investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The results show that the minor addition of Nb can shorten the start time of the amorphization reaction, improve the glass forming ability of Zr-Cu alloys, but cannot promote the formation of a single amorphous phase at a lower rotation speed of 200 rpm. The glass forming ability of the Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) alloys increases with increasing Nb additions. At a higher rotation speed of 350 rpm, a single amorphous phase of Zr{sub 66.7-x}Cu{sub 33.3}Nb{sub x} (x = 0, 2, 4) can be successfully fabricated. Moreover, the Nb addition into Zr-Cu alloys can accelerate the amorphization process and improve the stability of the amorphous phase against the mechanically induced crystallization. Furthermore, the amorphous Zr{sub 66.7}Cu{sub 33.3} phase gradually transforms into a metastable fcc-Zr{sub 2}Cu phase with increasing milling time.

  20. Performance improvement of charge-trap memory by using a stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhenjie; Hu, Dan; Zhang, Xiwei; Zhao, Yage [College of Physics and Electronic Engineering, Anyang Normal University, Anyang 455000 (China); Li, Rong [School of Mathematics and Statistics, Anyang Normal University, Anyang 455000 (China)

    2016-11-15

    The postdeposition annealing (PDA)-treated charge-trap flash memory capacitor with stacked Zr{sub 0.46}Si{sub 0.54}O{sub 2}/Al{sub 2}O{sub 3} charge-trapping layer flanked by a SiO{sub 2} tunneling oxide and an Al{sub 2}O{sub 3} blocking oxide was fabricated and investigated. It is observed that the memory capacitor exhibits prominent memory characteristics with large memory windows 12.8 V in a ±10 V gate sweeping voltage range, faster program/erase speed, and good data-retention characteristics even at 125 C compared to a single charge-trapping layer (Zr{sub 0.46}Si{sub 0.54}O{sub 2}, Zr{sub 0.79}Si{sub 0.21}O{sub 2}, and Zr{sub 0.46}Al{sub 1.08}O{sub 2.54}). The quantum wells and introduced interfacial traps of the stacked trapping layer regulate the storage and loss behavior of charges, and jointly contribute to the improved memory characteristics. Hence, the memory capacitor with a stacked trapping layer is a promising candidate in future nonvolatile charge-trap memory device design and application. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Preparation, structural characterization, and enhanced electrical conductivity of pyrochlore-type (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Xia, X.L. [Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin (China); Institute of Oceanography Instruments, Shandong Academy of Science, Chinese National Engineering Research Center for Marine Monitoring Equipment, Qingdao (China); Liu, Z.G.; Ouyang, J.H. [Institute for Advanced Ceramics, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin (China); Zheng, Y. [Institute of Oceanography Instruments, Shandong Academy of Science, Chinese National Engineering Research Center for Marine Monitoring Equipment, Qingdao (China)

    2012-08-15

    (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} (0 {<=} x {<=} 1.0) samples are prepared by solid state reaction method using Sm{sub 2}O{sub 3}, Eu{sub 2}O{sub 3}, and ZrO{sub 2} as starting materials. The phase composition and microstructure of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics are investigated by X-ray diffraction (XRD), scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM) coupled with selected area electron diffraction and Raman spectroscopy. XRD and TEM show that all the samples exhibit a single pyrochlore-type structure. HRTEM observation indicates that the whole grain interior of Sm{sub 2}Zr{sub 2}O{sub 7} ceramic is a perfect crystal free of any dislocation. Raman spectroscopy reveals that the degree of structural disorder of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics increases gradually with increasing Eu content. The electrical conductivity of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics is investigated by impedance spectroscopy in the air and hydrogen atmospheres, respectively. The electrical conductivity of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} ceramics increases with increasing Eu content at identical temperature levels. Both the activation energy E{sub g} and the pre-exponential factor {sigma}{sub 0g} for the grain conductivity gradually increase with increasing Eu content. As the ionic conductivity shows no obvious change in both air and hydrogen atmospheres, the conduction of (Sm{sub 1-x}Eu{sub x}){sub 2}Zr{sub 2}O{sub 7} is purely ionic with negligible electronic conduction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Analysis of cement solidified product and ash samples and preparation of a reference material

    International Nuclear Information System (INIS)

    Ishimori, Ken-ichiro; Haraga, Tomoko; Shimada, Asako; Kameo, Yutaka; Takahashi, Kuniaki

    2010-08-01

    Simple and rapid analytical methods for radionuclides in low-level radioactive waste have been developed by the present authors. The methods were applied to simulated solidified products and actual metal wastes to confirm their usefulness. The results were summarized as analytical guide lines. In the present work, cement solidified product and ash waste were analyzed followed by the analytical guide lines and subjects were picked up and solved for the application of the analytical guide lines to these wastes. Pulverization and homogenization method for ash waste was improved to prevent a contamination since the radioactivity concentrations of the ash samples were relatively high. Pre-treatment method was altered for the cement solidified product and ash samples taking account for their high concentration of Ca. Newly, an analytical method was also developed to measure 129 I with a dynamic reaction cell inductively coupled plasma mass spectrometer. In the analytical test based on the improved guide lines, gamma-ray emitting nuclides, 60 Co and 137 Cs, were measured to estimate the radioactivity of the other alpha and beta-ray emitting nuclides. The radionuclides assumed detectable, 3 H, 14 C, 36 Cl, 63 Ni, 90 Sr, and alpha-ray emitting nuclides, were analyzed with the improved analytical guide lines and their applicability for cement solidified product and ash samples were confirmed. Additionally a cement solidified product sample was evaluated in terms of the homogeneity and the radioactivity concentrations in order to prepare a reference material for radiochemical analysis. (author)

  3. On confirmation of abandonment of imported waste (glass solidified bodies) outside business places

    International Nuclear Information System (INIS)

    1996-01-01

    Electric power companies entrust the reprocessing of spent fuel generated from nuclear power stations to COGEMA in France, and in April, 1995, 28 high level radioactive wastes (glass solidified bodies) generated by the reprocessing were returned. When these glass solidified wastes are abandoned in the waste management facility of Japan Nuclear Fuel Service Co., it was decided to receive the confirmation of the prime minister on the measures based on the relevant law. Four electric power companies submitted the application and the explanation paper. As to the contents of the glass solidified wastes, the technical inspection was carried out by Bureau Veritas. Considering that this import of glass solidified wastes is the first in Japan, Science and Technology Agency carried out the measurement of all 28 wastes. The results are reported. It was confirmed that the measures for the abandonment taken by four electric power companies conform to the stipulation. The contents of the confirmation are reported in the order of the stipulation. These wastes were solidified with borosilicate glass in 5 mm thick stainless steel vessels, and the welding was done properly. (K.I.)

  4. Nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tashlykova-Bushkevich, Iya I. [Belarusian State University of Informatics and Radioelectronics, Minsk (Belarus)

    2015-12-31

    The present work summarizes recent progress in the investigation of nanoscale microstructure effects on hydrogen behavior in rapidly solidified aluminum alloys foils produced at exceptionally high cooling rates. We focus here on the potential of modification of hydrogen desorption kinetics in respect to weak and strong trapping sites that could serve as hydrogen sinks in Al materials. It is shown that it is important to elucidate the surface microstructure of the Al alloy foils at the submicrometer scale because rapidly solidified microstructural features affect hydrogen trapping at nanostructured defects. We discuss the profound influence of solute atoms on hydrogen−lattice defect interactions in the alloys. with emphasis on role of vacancies in hydrogen evolution; both rapidly solidified pure Al and conventionally processed aluminum samples are considered.

  5. Primary Dendrite Arm Spacings in Al-7Si Alloy Directionally Solidified on the International Space Station

    Science.gov (United States)

    Angart, Samuel; Lauer, Mark; Poirier, David; Tewari, Surendra; Rajamure, Ravi; Grugel, Richard

    2015-01-01

    Samples from directionally solidified Al- 7 wt. % Si have been analyzed for primary dendrite arm spacing (lambda) and radial macrosegregation. The alloy was directionally solidified (DS) aboard the ISS to determine the effect of mitigating convection on lambda and macrosegregation. Samples from terrestrial DS-experiments thermal histories are discussed for comparison. In some experiments, lambda was measured in microstructures that developed during the transition from one speed to another. To represent DS in the presence of no convection, the Hunt-Lu model was used to represent diffusion controlled growth under steady-state conditions. By sectioning cross-sections throughout the entire length of a solidified sample, lambda was measured and calculated using the model. During steady-state, there was reasonable agreement between the measured and calculated lambda's in the space-grown samples. In terrestrial samples, the differences between measured and calculated lambda's indicated that the dendritic growth was influenced by convection.

  6. A Study on Factors Affecting Strength of Solidified Peat through XRD and FESEM Analysis

    Science.gov (United States)

    Rahman, J. A.; Napia, A. M. A.; Nazri, M. A. A.; Mohamed, R. M. S. R.; Al-Geethi, A. S.

    2018-04-01

    Peat is soft soil that often causes multiple problems to construction. Peat has low shear strength and high deformation characteristics. Thus, peat soil needs to be stabilized or treated. Study on peat stabilization has been conducted for decades with various admixtures and mixing formulations. This project intends to provide an overview of the solidification of peat soil and the factors that affecting the strength of solidified peat soil. Three types of peats which are fabric, hemic and sapric were used in this study to understand the differences on the effect. The understanding of the factors affecting strength of solidified peat in this study is limited to XRD and FESEM analysis only. Peat samples were collected at Pontian, Johor and Parit Raja, Johor. Peat soil was solidified using fly ash, bottom ash and Portland cement with two mixing formulation following literature review. The solidified peat were cured for 7 days, 14 days, 28 days and 56 days. All samples were tested using Unconfined Compressive Strength Test (UCS), X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM). The compressive strength test of solidified peat had shown consistently increase of sheer strength, qu for Mixing 1 while decrease of its compressive strength value for Mixing 2. All samples were tested and compared for each curing days. Through XRD, it is found that all solidified peat are dominated with pargasite and richterite. The highest qu is Fabric Mixing 1(FM1) with the value of 105.94 kPa. This sample were proven contain pargasite. Samples with high qu were observed to be having fly ash and bottom ash bound together with the help of pargasite. Sample with decreasing strength showed less amount of pargasite in it. In can be concluded that XRD and FESEM findings are in line with UCS values.

  7. Microstructure and mechanical properties of an Al–Mg alloy solidified under high pressures

    International Nuclear Information System (INIS)

    Jie, J.C.; Zou, C.M.; Brosh, E.; Wang, H.W.; Wei, Z.J.; Li, T.J.

    2013-01-01

    Highlights: •Al–42.2Mg alloy was solidified under pressures of 1, 2, and 3 GPa and the microstructure analyzed. •A thermodynamic calculation of the Al–Mg phase diagram at high pressures was performed. •The phase content changes from predominantly γ-Al 12 Mg 17 at 1 GPa to FCC solid solution at 3 GPa. •The β-Al 3 Mg 2 is predicted to remain stable at low temperatures but is not observed. •The alloy solidified at high pressure has remarkably enhanced ultimate tensile strength. -- Abstract: Phase formation, the microstructure and its evolution, and the mechanical properties of an Al–42.2 at.% Mg alloy solidified under high pressures were investigated. After solidification at pressures of 1 GPa and 2 GPa, the main phase is the γ phase, richer in Al than in equilibrium condition. When the pressure is further increased to 3 GPa, the main phase is the supersaturated Al(Mg) solid solution with Mg solubility up to 41.6 at.%. Unlike in similar alloys solidified at ambient pressure, the β phase does not appear. Calculated high-pressure phase diagrams of the Al–Mg system show that although the stability range of the β phase is diminished with pressure, it is still thermodynamically stable at room temperature. Hence, the disappearance of the β phase is interpreted as kinetic suppression, due to the slow diffusion rate at high pressures, which inhibits solid–solid reactions. The Al–42.2 at.% Mg alloy solidified under 3 GPa has remarkably enhanced ultimate tensile strength compared to the alloy solidified under normal atmospheric pressure

  8. Structural and dynamical properties of the Cu{sub 46}Zr{sub 54} alloy in crystalline, amorphous and liquid state: A molecular dynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Valencia-Balvin, Camilo, E-mail: cavalen@fisica.udea.edu.c [Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia); ITM Institucion Universitaria, A.A 54959 Medellin (Colombia); Loyola, Claudia [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Osorio-Guillen, Jorge [Instituto de Fisica, Universidad de Antioquia, A.A. 1226 Medellin (Colombia); Gutierrez, Gonzalo [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile)

    2010-12-15

    Molecular dynamics simulations for the crystal, amorphous and liquid Cu{sub 46}Zr{sub 54} alloy were carried out on a system with up to 2000 particles, using a pairwise potential of the Rosato-Guillope-Legrand type. All simulations were done in the microcanonical ensemble, for a initial density of 5.76 g/cm{sup 3}, at different temperatures. A detailed analysis has been made by means of the pair-correlation function, coordination number, angle distribution, diffusion coefficient and vibrational density of states. We compared the main peaks of the amorphous phase with experimental data, obtaining a good agreement. The analysis of coordination number for the amorphous phase shows that the main building block of this phase are distorted icosahedron.

  9. Mechanism of tailored magnetic anisotropy in amorphous Co{sub 68}Fe{sub 24}Zr{sub 8} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yu, E-mail: yu.fu@uni-due.de, E-mail: cangcangzhulin@gmail.com; Meckenstock, R.; Farle, M. [Fakultät für Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, 47057 Duisburg (Germany); Barsukov, I., E-mail: ibarsuko@uci.edu [Fakultät für Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, 47057 Duisburg (Germany); Physics and Astronomy, University of California, Irvine, California 92697 (United States); Lindner, J. [Fakultät für Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, 47057 Duisburg (Germany); Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstr. 400, 01328 Dresden (Germany); Raanaei, H. [Department of Physics, Persian Gulf University, Bushehr 75169 (Iran, Islamic Republic of); Hjörvarsson, B. [Department of Physics and Astronomy, Uppsala University, Box 516 SE-75120 Uppsala (Sweden)

    2014-02-17

    The mechanism of tailored magnetic anisotropy in amorphous Co{sub 68}Fe{sub 24}Zr{sub 8} thin films was investigated by ferromagnetic resonance (FMR) on samples deposited without an applied magnetic field, with an out-of-plane field and an in-plane field. Analysis of FMR spectra profiles, high frequency susceptibility calculations, and statistical simulations using a distribution of local uniaxial magnetic anisotropy reveal the presence of atomic configurations with local uniaxial anisotropy, of which the direction can be tailored while the magnitude remains at an intrinsically constant value of 3.0(2) kJ/m{sup 3}. The in-plane growth field remarkably sharpens the anisotropy distribution and increases the sample homogeneity. The results benefit designing multilayer spintronic devices based on highly homogeneous amorphous layers with tailored magnetic anisotropy.

  10. Non-linear effects of initial melt temperatures on microstructures and mechanical properties during quenching process of liquid Cu{sub 46}Zr{sub 54} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Yun-Fei [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Liu, Rang-Su, E-mail: liurangsu@sina.com [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Tian, Ze-An; Liang, Yong-Chao [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Zhang, Hai-Tao [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Department of Electronic and Communication Engineering, Changsha University, Changsha 410003 (China); Hou, Zhao-Yang [Department of Applied Physics, Chang’an University, Xi’an 710064 (China); Liu, Hai-Rong [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Zhang, Ai-long [College of Physics and Electronics, Hunan University of Arts and Science, Changde 415000 (China); Zhou, Li-Li [Department of Information Engineering, Gannan Medical University, Ganzhou 341000 (China); Peng, Ping [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Xie, Zhong [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China)

    2015-05-15

    A MD simulation of liquid Cu{sub 46}Zr{sub 54} alloys has been performed for understanding the effects of initial melt temperatures on the microstructural evolution and mechanical properties during quenching process. By using several microstructural analyzing methods, it is found that the icosahedral and defective icosahedral clusters play a key role in the microstructure transition. All the final solidification structures obtained at different initial melt temperatures are of amorphous structures, and their structural and mechanical properties are non-linearly related to the initial melt temperatures, and fluctuated in a certain range. Especially, there exists a best initial melt temperature, from which the glass configuration possesses the highest packing density, the optimal elastic constants, and the smaller extent of structural softening under deforming.

  11. Evaluating Primary Dendrite Trunk Diameters in Directionally Solidified Al-Si Alloys

    Science.gov (United States)

    Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2014-01-01

    The primary dendrite trunk diameters of Al-Si alloys that were directionally solidified over a range of processing conditions have been measured. These data are analyzed with a model based primarily on an assessment of secondary dendrite arm dissolution in the mushy zone. Good fit with the experimental data is seen and it is suggested that the primary dendrite trunk diameter is a useful metric that correlates well with the actual solidification processing parameters. These results are placed in context with the limited results from the aluminium - 7 wt. % silicon samples directionally solidified aboard the International Space Station as part of the MICAST project.

  12. Optimized functionally graded La{sub 2}Zr{sub 2}O{sub 7}/8YSZ thermal barrier coatings fabricated by suspension plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chaohui [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, You, E-mail: wangyou@hit.edu.cn [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Fan, Shan; You, Yuan [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, Liang [Key Laboratory of Inorganic Coating Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899 (China); Yang, Changlong [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Sun, Xiaoguang [National Engineering Research Center for High-speed EMU, CSR Qingdao Sifang Co. Ltd., Qingdao 266111 (China); Li, Xuewei [Laboratory of Nano Surface Engineering, School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-11-15

    In this paper, an optimized functionally graded coating (OFGC) was successfully fabricated by suspension plasma spraying (SPS) with feedstocks of the suspension of nanoparticles. La{sub 2}Zr{sub 2}O{sub 7}/8YSZ OFGC with gradual compositional variation along the through-thickness direction is proposed to mitigate spallation and crack formation owing to the high residual stresses caused by frequent thermal cycling for TBCs. The single ceramic layer coatings (SCLC) of LZ and double ceramic layer coatings (DCLC) of LZ/8YSZ were fabricated by SPS as comparison. The phase composition and microstructure of the SCLC, OFGC and DCLC were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and Energy Dispersive Spectrometer (EDS). Moreover, the thermal cycling tests were carried out to evaluate their thermal shock behavior. Changes in weight and morphology of specimens were analyzed during thermal cycling tests. The results showed that OFGC has extended lifetime compared with SCLC and DCLC. The failure of DCLC with clear interface between different ceramic layers occurred via delamination mode, as a result of crack initiation and propagation generated by thermal mismatch between LZ and 8YSZ. While the failure of OFGC occurred in thermally grown oxide (TGO) layers, indicating that the gradual compositional variation avoided thermal stress concentration in the top ceramic layers. - Highlights: • Optimized functionally graded coatings and double ceramic layer coatings were deposited by suspension plasma spray. • The graded area of OFGC is continuously changed from inner 8YSZ to outer La{sub 2}Zr{sub 2}O{sub 7} (LZ). • The OFGC shows a more extended thermal cycling life than the LZ SCLC and LZ/8YSZ DCLC. • Various failure mechanisms were proposed to explain thermal cycling behavior.

  13. Effect of synthesis conditions on the nanopowder properties of Ce{sub 0.9}Zr{sub 0.1}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Zimicz, M.G.; Fabregas, I.O.; Lamas, D.G. [CINSO (Centro de Investigaciones en Solidos) CONICET-CITEFA J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Larrondo, S.A., E-mail: susana@di.fcen.uba.ar [Laboratorio de Procesos Cataliticos, Departamento de Ingenieria Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Pabellon de Industrias, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

    2011-06-15

    Graphical abstract: . The synthesis of nanocrystalline Ce{sub 0.9}Zr{sub 0.1}O{sub 2} powders via the gel-combustion method, using different fuels, and following either stoichiometric or non-stoichiometric pH-controlled routes is investigated. Research highlights: {yields} All samples exhibited the fluorite-type crystal structure, nanometric average crystallite size and negligible carbon content. {yields} Synthesis conditions strongly affect the average crystallite size, the degree of agglomeration, the specific surface area and the pore volume. {yields} Our results indicate that, by controlling the synthesis conditions it is possible to obtain solids with custom-made morphological properties. -- Abstract: In this work, the synthesis of nanocrystalline Ce{sub 0.9}Zr{sub 0.1}O{sub 2} powders via the gel-combustion method, using different fuels, and following either stoichiometric or non-stoichiometric pH-controlled routes is investigated. The objective is to evaluate the effect of synthesis conditions on the textural and morphological properties, and the crystal structure of the synthesized materials. The solids were characterized by nitrogen physisorption, Scanning Electron Microscopy (SEM), X-ray powder diffraction (XPD), and Carbon-Hydrogen-Nitrogen Elemental Analysis (CHN). All the powders exhibited nanometric crystallite size, fluorite-type structure and negligible carbon content. Synthesis conditions strongly affect the average crystallite size, the degree of agglomeration, the specific surface area and the pore volume. Our results indicate that, by controlling the synthesis conditions it is possible to obtain solids with custom-made morphological properties.

  14. Radiochemical analysis of homogeneously solidified low level radioactive waste from nuclear power plants

    International Nuclear Information System (INIS)

    Sato, Kaneaki; Ikeuchi, Yoshihiro; Higuchi, Hideo

    1995-01-01

    As mentioned above, we have reliable radioanalytical methods for all kinds of homogeneously solidified wastes. We are now under studying an analytical method for pellets which are made from evaporator concentrates or resin. And we are going to study to establish new analytical method for the rad-waste including metal, cloths and so on in near future. (J.P.N.)

  15. Evaluation of Carbonation Effects on Cement-Solidified Contaminated Soil Used in Road Subgrade

    Directory of Open Access Journals (Sweden)

    Yundong Zhou

    2018-01-01

    Full Text Available Cement solidification/stabilization is widely used towards contaminated soil since it has a low price and significant improvement for the structural capacity of soil. To increase the usage of the solidified matrix, cement-solidified contaminated soil was used as road subgrade material. In this study, carbonation effect that reflected the durability on strength characteristics of cement-solidified contaminated soil and the settlement of pavement were evaluated through experimental and numerical analysis, respectively. According to results, compressive strengths of specimens with 1% Pb(II under carbonation and standard curing range from 0.44 MPa to 1.17 MPa and 0.14 MPa to 2.67 MPa, respectively. The relatively low strengths were attributed to immobilization of heavy metal, which consumed part of SiO2, Al2O3, and CaO components in the cement or kaolin and reduced the hydration and pozzolanic reaction materials. This phenomenon further decreased the strength of solidified soils. The carbonation depth of 1% Cu(II or Zn(II contaminated soils was 18 mm, which significantly increased with the increase of curing time and contamination concentration. Furthermore, the finite element calculation results showed that surface settlements decreased with the increase of modulus of subgrade and the distance away from the center. At the center, the pavement settlement was proportional to the level of traffic load.

  16. Elution behavior of heavy metals from cement solidified products of incinerated ash waste - 59102

    International Nuclear Information System (INIS)

    Meguro, Yoshihiro; Kawato, Yoshimi; Nakayama, Takuya; Tomioka, Osamu; Mitsuda, Motoyuki

    2012-01-01

    A method, in which incinerated ash is solidified with a cement material, has been developed to dispose radioactive incinerated ash waste. In order to bury the solidified product, it is required that elution of hazardous heavy metals included in the ash from the solidified products is inhibited. In this study, the elution behavior of the heavy metals from the synthetic solidified products, which included Pb(II), Cd(II), and Cr(VI) and were prepared using ordinary portland cement (OPC), blast furnace slag cement (BFS), or a cement material that showed low alkalinity (LA-Cement), was investigated. Several chemicals and materials were added as additive agents to prevent the elution of the heavy metals. When OPC was used, Cd elution was inhibited, but Pb and Cr were not enough even using the additive agent examined. FeSO 4 and Na 2 S additive agents worked effective to inhibit elution of Cr. When BFS was used, the elution of Pb, Cd and Cr was inhibited for the all products prepared. In the case of LA-Cement, the elution of Pb and Cd was inhibited for the all products, but only the product that was added FeSO 4 showed good result of the elution of Cr. (authors)

  17. IAEA coordinated research program on the evaluation of solidified high-level radioactive waste products

    International Nuclear Information System (INIS)

    Grover, J.R.; Schneider, K.J.

    1979-01-01

    A coordinated research program on the evaluation of solidified high-level radioactive waste products has been active with the IAEA since 1976. The program's objectives are to integrate research and to provide a data bank on an international basis in this subject area. Results and considerations to date are presented

  18. Effect of drying-wetting cycles on leaching behavior of cement solidified lead-contaminated soil.

    Science.gov (United States)

    Li, Jiang-Shan; Xue, Qiang; Wang, Ping; Li, Zhen-Ze; Liu, Lei

    2014-12-01

    Lead contaminated soil was treated by different concentration of ordinary Portland cement (OPC). Solidified cylindrical samples were dried at 40°C in oven for 48 h subsequent to 24h of immersing in different solution for one drying-wetting. 10 cycles were conducted on specimens. The changes in mass loss of specimens, as well as leaching concentration and pH of filtered leachates were studied after each cycle. Results indicated that drying-wetting cycles could accelerate the leaching and deterioration of solidified specimens. The cumulative leached lead with acetic acid (pH=2.88) in this study was 109, 83 and 71 mg respectively for solidified specimens of cement-to-dry soil (C/Sd) ratios 0.2, 0.3 and 0.4, compared to 37, 30, and 25mg for a semi-dynamic leaching test. With the increase of cycle times, the cumulative mass loss of specimens increased linearly, but pH of filtered leachates decreased. The leachability and deterioration of solidified specimens increased with acidity of solution. Increases of C/Sd clearly reduced the leachability and deterioration behavior. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Influence of Short-time Oxidation on Corrosion Properties of Directionally Solidified Superalloys with Different Orientations

    Directory of Open Access Journals (Sweden)

    MA Luo-ning

    2016-07-01

    Full Text Available In order to investigate the corrosion performance on intersecting and longitudinal surfaces of unoxidized and oxidized directionally solidified superalloys, Ni-base directionally solidified superalloy DZ125 and Co-base directionally solidified superalloy DZ40M were selected. Oxidation behavior on both alloys with different orientations was investigated at 1050℃ at different times, simulating the oxidation process of vanes or blades in service; subsequent electrochemical performance in 3.5%NaCl aqueous solution was studied on two orientations of unoxidized and oxidized alloys, simulating the corrosion process of superalloy during downtime. The results show that grain boundaries and sub-boundaries of directionally solidified superalloys are susceptible to corrosion and thus longitudinal surface with lower area fraction of grain boundaries has higher corrosion resistance. Compared to intersecting surface of alloys, the structure of grain boundaries of longitudinal surface is less conducive to diffusion and thus the oxidation rate on longitudinal surface is lower. Formation of oxide layers on alloys after short-time oxidation provides protective effect and enhances the corrosion resistance.

  20. Performance criteria for solidified high-level radioactive wastes. Environmental impact statement. Revision 1

    International Nuclear Information System (INIS)

    1977-09-01

    This draft Environmental Impact Statement on performance criteria for solidified high-level radioactive wastes (PCSHLW) covers: considerations for PCSHLW development, the proposed rulemaking, characteristics of the PCSHLW, environmental impacts of the proposed PCSHLW, alternatives to the PCSHLW criteria, and cost/benefit/risk evaluation. Five appendices are included to support the technical data required in the Environmental Impact Statement

  1. The evaluation of solidifying performance of heavy metal waste using cementitious materials (2)

    International Nuclear Information System (INIS)

    Fujita, Hideki; Harasawa, Shuichi

    2005-02-01

    Some of radioactive waste generated from JNC's facilities contain the poisonous substances such as lead, cadmium and mercury. In order to establish an appropriate method of the treatment of these heavy metals, solidification performance was evaluated using cementitious materials. In this report, the solidification performance of lead and mercury, which accounts for relatively high ratio in total wastes, was evaluated. The results are summarized below: 1. The test of stabilization process of mercury. The conversion process from mercury to the powdery mercury sulfide (red) was examined on the beaker scale. As a result, it was confirmed that the conversion was possible using the liquid phase reaction at 80deg C by the addition of sulfur powder with the NaOH solution. After the process, the mercury concentration in the filtrate was relatively high (0.6 mass%), so it was judged that the reuse of the recovered mercury waste fluid was indispensable. 2. The fabrication and evaluation of solidified wastes. The solidified waste were fabricated with cementitious material, and were evaluated by the measurement of one-axis compressive strength, the elution ratio of lead, mercury and so on. Powdery lead sulfide and the mercury sulfide of reagent were used as model waste. (1) solidification test of the lead waste. It was confirmed one-axis compressive strength for all solidified waste to pass the technical standards 15 kg/cm 2 (1.5 Mpa) for homogeneously solidified waste as the Low-level Radioactive Waste Disposal Center in Aomori Prefecture, and as for the elution ratio of lead, it had obtained the better result (0.06 mg/L) at the case of solidification of sulfide lead 30 mass% packed in the total solidified waste by using Highly Fly-ash contained Silica fume Cement (HFSC) than standard value (0.3 mg/L) at Regulations of Waste Management and Public Cleansing Law. Additionally, it was confirmed the using admixture of the inorganic reducing agent such as the Iron (II) chloride

  2. Structural features and the microscopic dynamics of the three-component Zr{sub 47}Cu{sub 46}Al{sub 7} system: Equilibrium melt, supercooled melt, and amorphous alloy

    Energy Technology Data Exchange (ETDEWEB)

    Khusnutdinoff, R. M., E-mail: khrm@mail.ru; Mokshin, A. V., E-mail: anatolii.mokshin@mail.ru [Kazan Federal University (Russian Federation); Klumov, B. A.; Ryltsev, R. E.; Chtchelkatchev, N. M. [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

    2016-08-15

    The structural and dynamic properties of the three-component Zr{sub 47}Cu{sub 46}Al{sub 7} system are subjected to a molecular dynamics simulation in the temperature range T = 250–3000 K at a pressure p = 1.0 bar. The temperature dependences of the Wendt–Abraham parameter and the translation order parameter are used to determine the glass transition temperature in the Zr{sub 47}Cu{sub 46}Al{sub 7} system, which is found to be T{sub c} ≈ 750 K. It is found that the bulk amorphous Zr{sub 47}Cu{sub 46}Al{sub 7} alloy contains localized regions with an ordered atomic structures. Cluster analysis of configuration simulation data reveals the existence of quasi-icosahedral clusters in amorphous metallic Zr–Cu–Al alloys. The spectral densities of time radial distribution functions of the longitudinal (C̃{sub L}(k, ω)) and transverse (C̃{sub T}(k, ω)) fluxes are calculated in a wide wavenumber range in order to study the mechanisms of formation of atomic collective excitations in the Zr{sub 47}Cu{sub 46}Al{sub 7} system. It was found that a linear combination of three Gaussian functions is sufficient to reproduce the (C̃{sub L}(k, ω)) spectra, whereas at least four Gaussian contributions are necessary to exactly describe the (C̃{sub T}(k, ω)) spectra of the supercooled melt and the amorphous metallic alloy. It is shown that the collective atomic excitations in the equilibrium melt at T = 3000 K and in the amorphous metallic alloy at T = 250 K are characterized by two dispersion acoustic-like branches related with longitudinal and transverse polarizations.

  3. Stability of low-temperature Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} cubic phase: The role of temperature and atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Quinzeni, Irene; Capsoni, Doretta; Berbenni, Vittorio; Mustarelli, Piercarlo [Chemistry Department, Physical-Chemistry Section, University of Pavia, Viale Taramelli 16, 27100 Pavia (Italy); Sturini, Michela [Chemistry Department, Analytical Section, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy); Bini, Marcella, E-mail: bini@unipv.it [Chemistry Department, Physical-Chemistry Section, University of Pavia, Viale Taramelli 16, 27100 Pavia (Italy)

    2017-01-01

    Rechargeable all solid-state lithium batteries are a promising technology for the next generation of safer batteries. In this context, strict requirements are placed on the electrolytes, among which is emerging the Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} garnet, chiefly for the relationships among synthesis conditions and phase stability. Here, the structural modifications of the low temperature (LT) Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} cubic form were investigated by using in situ X-Rays diffraction analysis. In particular, we studied the role of both temperature and atmosphere (air or argon) on phase stabilization. In argon flow, the LT phase is stable under 750 °C, and it transforms into the tetragonal one at lower temperature. In air, it partially decomposes to La{sub 2}Zr{sub 2}O{sub 7} due to Li loss above 250 °C. ICP-OES analysis confirmed that garnet stoichiometry was maintained in argon, whereas in air lithium loss occurred. The structural transformations are driven by the CO{sub 2} absorbed in the LT structure that can form Li{sub 2}CO{sub 3} and/or La{sub 2}(CO{sub 3}){sub 3} so causing stoichiometry changes responsible of the structural evolution. - Highlights: • Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} is a promising electrolyte for rechargeable all solid state batteries. • The stability of low temperature cubic phase of garnet in argon and air was determined. • The garnet stoichiometry was maintained in argon while in air lithium loss occurred. • The influence of CO{sub 2} adsorption on the structural modifications of garnet was proved.

  4. Improvement in mechanical properties of hypereutectic Al-Si-Cu alloys through sono-solidified

    Directory of Open Access Journals (Sweden)

    Yoshiki Tsunekawa

    2014-07-01

    Full Text Available For the wider applications, it is necessary to improve the ductility as well as the strength and wear-resistance of hypereutectic Al-Si-Cu alloys, which are typical light-weight wear-resistant materials. An increase in the amounts of primary silicon particles causes the modified wear-resistance of hypereutectic Al-Si-Cu alloys, but leads to the poor strength and ductility. It is known that dual phase steels composed of hetero-structure have succeeded in bringing contradictory mechanical properties of high strength and ductility concurrently. In order to apply the idea of hetero-structure to hypereutectic Al-Si-Cu alloys for the achievement of high strength and ductility along with wear resistance, ultrasonic irradiation of the molten metal during the solidification, which is called sono-solidification, was carried out from its molten state to just above the eutectic temperature. The sono-solidified Al-17Si-4Cu alloy is composed of hetero-structure, which are, hard primary silicon particles, soft non-equilibrium a -Al phase and the eutectic region. Rheo-casting was performed at just above the eutectic temperature with sono-solidified slurry to shape a disk specimen. After the rheo-casting with modified sonosolidified slurry held for 45 s at 570 篊, the quantitative optical microscope observation exhibits that the microstructure is composed of 18area% of hard primary silicon particles and 57area% of soft a -Al phase. In contrast, there exist only 5 area% of primary silicon particles and no a -Al phase in rheo-cast specimen with normally solidified slurry. Hence the tensile tests of T6 treated rheo-cast specimens with modified sono-solidified slurry exhibit improved strength and 5% of elongation, regardless of having more than 3 times higher amounts of primary silicon particles compared to that of rheo-cast specimen with normally solidified slurry.

  5. Low temperature plasma-enhanced ALD TiN ultrathin films for Hf{sub 0.5}Zr{sub 0.5}O{sub 2}-based ferroelectric MIM structures

    Energy Technology Data Exchange (ETDEWEB)

    Kozodaev, M.G.; Chernikova, A.G.; Markeev, A.M. [Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny, Moscow Region 141700 (Russian Federation); Lebedinskii, Y.Y. [Moscow Institute of Physics and Technology, Institutsky Lane 9, Dolgoprudny, Moscow Region 141700 (Russian Federation); National Research Nuclear University MEPhI, Moscow Engineering Physics Institute, Kashirskoye Shosse 31, 115409 Moscow (Russian Federation); Polyakov, S.N. [Technological Institute for Superhard and Novel Carbon Materials, Tsentral' naya str. 7a, 142190, Troitsk, Moscow (Russian Federation)

    2017-06-15

    In this work chemical and electrical properties of TiN films, grown by low temperature plasma-enhanced atomic layer deposition (PE-ALD) process from TiCl{sub 4} and NH{sub 3}, were investigated. Electrical resistivity as low as 250 μOhm x cm, as well as the lowest Cl impurity content, was achieved at 320 C. Full-ALD Hf{sub 0.5}Zr{sub 0.5}O{sub 2}-based metal-ferroelectric-metal capacitor with TiN electrodes was fabricated and its electrical properties were investigated. It was also shown that the proposed PE-ALD process provides an early film continuity, which was confirmed by ultrathin fully continuous film growth. Such ultrathin (3 nm) and fully continuous TiN film was also successfully implemented as the top electrode to Hf{sub 0.5}Zr{sub 0.5}O{sub 2}-based ferroelectric capacitor. Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) was used for its thickness determination and a visible wake-up effect in underlying Hf{sub 0.5}Zr{sub 0.5}O{sub 2} layer was clearly observed. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Performance of cubic ZrO{sub 2} doped CeO{sub 2}: First-principles investigation on elastic, electronic and optical properties of Ce{sub 1−x} Zr{sub x}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Dong [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Zeng, Chunhua, E-mail: zchh2009@126.com [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Faculty of Science, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Wang, Hua, E-mail: wanghuaheat@hotmail.com [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Luo, Hongchun [Faculty of Science, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Cheng, Xianming [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Xiang, Chao [College of Mechanical and Electrical Engineering, Yangtze Normal University, Fuling 408100, Chongqing (China); Wei, Yonggang; Li, Kongzhai; Zhu, Xing [State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, Yunnan (China); Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, Yunnan (China)

    2016-06-25

    The structural, elastic, electronic and optical properties of Ce{sub 1−x} Zr{sub x}O{sub 2} (x = 0, 0.25, 0.5, 0.75, 1) fluorite type oxides are studied by researchers using the method of density functional theory (DFT) + U method. The calculated equilibrium lattice parameter, cell volume, elastic and optical properties for CeO{sub 2} and ZrO{sub 2} are all in good agreement with the available experimental data and other theoretical results. It is found that Ce substituted by Zr leads to the formation of the pseudo-cubic fluorite-type structure. With doping concentration × increasing, the lattice parameter, cell volume and the bond length of d{sub Ce−O} and d{sub Zr−O} decrease linearly. It is interesting to find that the hardness of materials increase with Zr concentration increasing. For Ce{sub 0.75} Zr{sub 0.25} O{sub 2}, we also find that its ductility is good. Meanwhile, the range of the conduction band energy in the doped system becomes wider than that in the undoped system. The overlapping band phenomenon occur for all substitutions in Ce{sub 1−x} Zr{sub x}O{sub 2} (from x = 0.25 to x = 0.75), especially for the structure of Ce{sub 0.5} Zr{sub 0.5} O{sub 2} and Ce{sub 0.25} Zr{sub 0.75} O{sub 2}, its second band gaps almost disappear. Based on the dielectric functions obtained, it is shown that the static dielectric constant ε{sub 0} and refractive index n{sub 0} obviously decrease with Zr concentration increasing. After discussing, we know that CeO{sub 2} is suitable as a useful high-refractive index film material in single and multilayered optical coatings, whereas ZrO{sub 2} can be used as gate-dielectric materials in metal-oxide semiconductor (MOS) devices, in metallurgy and as a thermal barrier coating in engines. - Highlights: • Structural, and optical properties of fluorite type oxides are studied; • Ce substituted by Zr leads to formation of pseudo-cubic fluorite-type structure; • Hardness of materials are increased with Zr

  7. The evaluation of solidifying performance of heavy metal waste using cementitious materials

    International Nuclear Information System (INIS)

    Takei, Akihiko; Fujita, Hideki; Harasawa, Shuichi

    2004-02-01

    Some of radioactive waste generated form JNC's facilities contain the poisonous substances such as lead, cadmium and mercury. In order to establish an appropriate method of the treatment of these heavy metals, solidification performance was evaluated using cementitious materials. In this report, the solidification performance of lead, which accounts for relatively high ratio in total wastes, was evaluated. The results are summarized below: 1. The test of stabilization process of lead: The conversion process from block lead to the powdery lead sulfide was examined on the beaker scale. As a result, it was confirmed that the conversion was possible using the liquid phase reaction by the addition of thiourea after block lead had been dissolved by the acetic acid with bubbling air. After the process, the lead concentration in the filtrate was extremely low (0.02 mg/L), so it was judged that almost all of the lead was converted and recovered as lead sulfide. 2. The fabrication and evaluation of solidified wastes: Five types of solidified waste were fabricated with different binder, and were evaluated by the measurement of one-axis compressive strength, porosity, the elution ratio of lead, and so on. Powdery lead and sulfide lead reagent were used as model waste. As a result of the test, it was confirmed one-axis compressive strength for all solidified waste to pass the technical standards 15 kg/cm 2 (1.5 MPa) for homogeneously solidified waste as the Low-level Radioactive Waste Disposal Center in Aomori Prefecture, and as for the elution ratio of lead, it had obtained the better result (0.27 mg/L) at the case of solidification of sulfide lead 20 mass% packed in the total solidified waste by using low alkaline cement (including Hauyne mineral) than standard value (0.3 mg/L) at Regulations of Waste Management and Public Cleansing Law. Moreover, it was understood that the elution of lead had high relationship with not only the character of the binder but also the physical

  8. The solubility and site preference of Fe{sup 3+} in Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnets

    Energy Technology Data Exchange (ETDEWEB)

    Rettenwander, D., E-mail: daniel.rettenwander@sbg.ac.at [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria); Geiger, C.A. [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria); Tribus, M.; Tropper, P. [Institute of Mineralogy and Petrography, Faculty of Geo- and Atmospheric Sciences, University of Innsbruck, Innrain 52, 6020 Innsbruck (Austria); Wagner, R.; Tippelt, G.; Lottermoser, W.; Amthauer, G. [Department of Materials Research and Physics, University of Salzburg, 5020 Salzburg (Austria)

    2015-10-15

    A series of Fe{sup 3+}-bearing Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZO) garnets was synthesized using solid-state synthesis methods. The synthetic products were characterized compositionally using electron microprobe analysis and inductively coupled plasma optical emission spectroscopy (ICP-OES) and structurally using X-ray powder diffraction and {sup 57}Fe Mössbauer spectroscopy. A maximum of about 0.25 Fe{sup 3+} pfu could be incorporated in Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnet solid solutions. At Fe{sup 3+} concentrations lower than about 0.16 pfu, both tetragonal and cubic garnets were obtained in the synthesis experiments. X-ray powder diffraction analysis showed only a garnet phase for syntheses with starting materials having intended Fe{sup 3+} contents lower than 0.52 Fe{sup 3+} pfu. Back-scattered electron images made with an electron microprobe also showed no phase other than garnet for these compositions. The lattice parameter, a{sub 0}, for all solid-solution garnets is similar with a value of a{sub 0}≈12.98 Å regardless of the amount of Fe{sup 3+}. {sup 57}Fe Mössbauer spectroscopic measurements indicate the presence of poorly- or nano-crystalline FeLaO{sub 3} in syntheses with Fe{sup 3+} contents greater than 0.16 Fe{sup 3+} pfu. The composition of different phase pure Li{sub 7−3x}Fe{sub x}La{sub 3}Zr{sub 2}O{sub 12} garnets, as determined by electron microprobe (Fe, La, Zr) and ICP-OES (Li) measurements, give Li{sub 6.89}Fe{sub 0.03}La{sub 3.05}Zr{sub 2.01}O{sub 12}, Li{sub 6.66}Fe{sub 0.06}La{sub 3.06}Zr{sub 2.01}O{sub 12}, Li{sub 6.54}Fe{sub 0.12}La{sub 3.01}Zr{sub 1.98}O{sub 12}, and Li{sub 6.19}Fe{sub 0.19}La{sub 3.02}Zr{sub 2.04}O{sub 12}. The {sup 57}Fe Mössbauer spectrum of cubic Li{sub 6.54}Fe{sub 0.12}La{sub 3.01}Zr{sub 1.98}O{sub 12} garnet indicates that most Fe{sup 3+} occurs at the special crystallographic 24d position, which is the standard tetrahedrally coordinated site in garnet. Fe{sup 3+} in smaller

  9. Anti-irradiation performance against helium bombardment in bulk metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5}

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Wang, Bin; Dong, Chuang; Gong, Faquan; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2013-07-15

    Highlights: ► This paper used He{sup 2+} ion-irradiated metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} and the W metal with the energy of 500 keV. ► There was no significant irradiation damage phenomenon on the surface of metallic glass at different irradiation fluences. ► For irradiated W, the peeling, delamination and flaking appeared numerously at fluences of 1 × 10{sup 18} and 2 × 10{sup 18} ions/cm{sup 2}. ► The resistance to He{sup 2+} irradiation of metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} was superior to the one in W metal. -- Abstract: In order to compare the resistance to He{sup 2+} ion induced irradiation between metallic glass and polycrystal W metal, this paper used different fluences of He{sup 2+} ion-irradiated metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} and polycrystal W with an energy of 500 keV. The SRIM simulation calculation results showed that the range (1.19 μm) of He{sup 2+} in metallic glass was greater than the one (0.76 μm) in polycrystal W. The SEM analysis showed that there was no significant irradiation damage phenomenon on the surface of metallic glass, and there was only a damage layer 1.45 μm away from the surface when the fluence reached 2 × 10{sup 18} ions/cm{sup 2}. For W, there were surface peeling, flaking and other surface damages at a fluence of 1 × 10{sup 18} ions/cm{sup 2}; when the fluence increased to 2 × 10{sup 18} ions/cm{sup 2}, multilayer detachment phenomenon appeared. The surface root mean square roughness of metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} first increased and then decreased with the increase of fluence. The surface reflectivity of (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} decreased with the increase of fluence. Through detection by XRD, it was found that (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} always maintained amorphous phase after different fluences of radiation. The

  10. Comparison in processing routes by copper mold casting injection and suction in the Cu{sub 46}Zr{sub 42}Al{sub 7}Y{sub 5} vitreous alloy; Comparacao entre as rotas de processamento por fundicao com injecao e com succao da liga vitrea Cu{sub 46}Zr{sub 42}Al{sub 7}Y{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Batalha, W.; Aliaga, L.C.R.; Bolfarini, C.; Botta, W.J.; Kiminami, C.S. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2014-07-01

    To expand the application of glassy metals, the development of processing routes and compositions that allow the production of parts with dimensions of millimeters or even centimeters, is very important. The present work aims the contribution to the technological development of processing routes for the production of Cu-based bulk metallic glasses. Wedge-shaped samples of Cu{sub 46}Zr{sub 42}Al{sub 7}Y{sub 5} (atom percent) chemical composition were processed using copper mold casting by suction and injection. Characterization was made combining scanning electron microscopy, x-ray diffraction and differential scanning calorimetry. The critical amorphous thickness obtained by those two different routes was carefully observed. The suction route allow obtaining the best results with critical amorphous thickness about 8 mm. This result was analyzed considering the different extrinsic parameters to the glass forming ability of the alloy. (author)

  11. Evaluation of the electrochemical behavior of U{sub 2.5}Zr{sub 7.5}Nb and U{sub 3}Zr{sub 9}Nb uranium alloys in relation to the pH and the solution aeration

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, Fabio Abud; Santos, Ana Maria Matildes dos; Ferraz, Wilmar Barbosa; Figueiredo, Celia de Araujo, E-mail: ferraz@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    The Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) is developing, in cooperation with the Centro Tecnologico da Marinha (CTMSP), the advanced nuclear plate type fuel for the second core of the land-based reactor prototype of the Laboratorio de Geracao Nucleo-Eletrica (LABGENE). Recent investigations have shown that the fuel made of uranium-based niobium and zirconium alloys reaches the best performance relative to other fuels, e.g. UO{sub 2}. Niobium and Zirconium also increase the corrosion resistance and the mechanical strength of the uranium alloys. By means of electrochemical techniques the corrosion behavior of alloys U{sub 2}.{sub 5}Zr{sub 7.5}Nb and U{sub 3}Zr{sub 9}Nb, developed at CDTN and heat treated in the temperature range of 200 deg C to 600 deg C, was assessed. The effect of the parameters pH and solution aeration was studied as well as the influence of zirconium and niobium alloying elements in the corrosion of uranium. The techniques used were open circuit potential, electrochemical impedance and potentiodynamic anodic polarization at room temperature. The tests were performed in a three-electrode electrochemical cell with Ag/AgCl (3M KCl) as the reference electrode and a platinum plate as the auxiliary electrode. The potentiodynamic polarization curves of uranium and its alloys in acidic solutions showed regions with anodic currents limited by a passive film. The presence of niobium and zirconium contributed for the formation of this film. The impedance data showed the presence of two semicircles in the Bode diagram, indicating the occurrence of two distinct electrochemical processes. The data were fitted to an equivalent circuit model in order to obtain parameters of the electrochemical processes and evaluate the effect of the studied variables. (author)

  12. A study on H{sub 2}-TPR of Pt/Ce{sub 0.27}Zr{sub 0.73}O{sub 2} and Pt/Ce{sub 0.27}Zr{sub 0.70}La{sub 0.03}O{sub x} for soot oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hailong [College of Chemical Engineering, Sichuan University, Chengdu 610064 (China); Wang, Jianli; Zhang, Yanhua [College of Chemistry, Sichuan University, Chengdu 610064 (China); Jiao, Yi [Xi’an Modern Chemistry Research Institute, Xi’an 710065 (China); Ren, Chengjun; Gong, Maochu [College of Chemistry, Sichuan University, Chengdu 610064 (China); Chen, Yaoqiang, E-mail: nic7501@scu.edu.cn [College of Chemical Engineering, Sichuan University, Chengdu 610064 (China); College of Chemistry, Sichuan University, Chengdu 610064 (China); Sichuan Provincial Vehicular Exhaust Gases Abatement Engineering Technology Center, Chengdu 610064 (China); Sichuan Provincial Environmental Catalytic Material Engineering Technology Center, Chengdu 610064 (China)

    2016-07-30

    Highlights: • The H{sub 2} consumption of the catalyst increases after aging. • The availability of surface lattice oxygen could be improved after aging. • Sintering and encapsulation of Pt weaken H{sub 2} spillover mechanism. • Soot oxidation activity is closely related to reduction temperature. - Abstract: Pt/Ce{sub 0.27}Zr{sub 0.73}O{sub 2} and Pt/Ce{sub 0.27}Zr{sub 0.70}La{sub 0.03}O{sub x} catalysts, prepared by co-precipitation and impregnation methods, were thermally treated at different temperatures for 10 h and then characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), H{sub 2} temperature-programmed reduction (H{sub 2}-TPR), thermogravimetric analysis (TGA) and soot temperature-programmed oxidation (soot-TPO). Due to thermal effect on the structural and textural properties, the aged catalysts show increased reduction temperatures. But, interestingly, more H{sub 2} consumption is detected, which would be ascribed to the increased mobility of bulk oxygen and surface lattice oxygen. The promoting and synergistic roles of Pt in H{sub 2}-TPR are discussed and it reveals that the sintering and encapsulation of Pt would weaken the H{sub 2} spillover mechanism and the addition of La is beneficial to stabilize the synergistic effect between Pt and Ce. On the other hand, a humble role of Pt on promoting soot oxidation activity is found in this study. Not all oxygen species available in H{sub 2}-TPR can be used for soot oxidation. The deactivation of the aged catalysts is closely related to the reduction temperature.

  13. Validation of the solidifying soil process using laser-induced breakdown spectroscopy

    Science.gov (United States)

    Lin, Zhao-Xiang; Liu, Lin-Mei; Liu, Lu-Wen

    2016-09-01

    Although an Ionic Soil Stabilizer (ISS) has been widely used in landslide control, it is desirable to effectively monitor the stabilization process. With the application of laser-induced breakdown spectroscopy (LIBS), the ion contents of K, Ca, Na, Mg, Al, and Si in the permeable fluid are detected after the solidified soil samples have been permeated. The processes of the Ca ion exchange are analyzed at pressures of 2 and 3 atm, and it was determined that the cation exchanged faster as the pressure increased. The Ca ion exchanges were monitored for different stabilizer mixtures, and it was found that a ratio of 1:200 of ISS to soil is most effective. The investigated plasticity and liquidity indexes also showed that the 1:200 ratio delivers the best performance. The research work indicates that it is possible to evaluate the engineering performances of soil solidified by ISS in real time and online by LIBS.

  14. Accelerated leach testing of radionuclides from solidified low-level waste

    International Nuclear Information System (INIS)

    Pietrzak, R.F.; Fuhrmann, M.; Franz, E.M.; Heiser, J. III; Colombo, P.

    1989-01-01

    This paper describes some of the work performed to develop an accelerated leach test designed to provide data that show long-term leaching behavior of solidified waste in a relatively short period of testing (1,2). The need for an accelerated leach test stems from the fact that the response of an effectively solidified waste form to the leaching process is so slow that a very long time is required to complete a test which shows the long-term leaching behavior of a waste form. Because of time limitations, as well as economic considerations, most studies have been limited to the early stages of the leaching process which is predominantly controlled by diffusion, although acknowledged to be due to also dissolution, corrosion or ion-exchange

  15. Modeling Macrosegregation in Directionally Solidified Aluminum Alloys under Gravitational and Microgravitational Conditions.

    Energy Technology Data Exchange (ETDEWEB)

    Lauer, Mark A.; Poirier, David R.; Erdmann, Robert G.; Tewari, Surendra N.; Madison, Jonathan D

    2014-09-01

    This report covers the modeling of seven directionally solidified samples, five under normal gravitational conditions and two in microgravity. A model is presented to predict macrosegregation during the melting phases of samples solidified under microgravitational conditions. The results of this model are compared against two samples processed in microgravity and good agreement is found. A second model is presented that captures thermosolutal convection during directional solidification. Results for this model are compared across several experiments and quantitative comparisons are made between the model and the experimentally obtained radial macrosegregation profiles with good agreement being found. Changes in cross section were present in some samples and micrographs of these are qualitatively compared with the results of the simulations. It is found that macrosegregation patterns can be affected by changing the mold material.

  16. Functions and requirements document for interim store solidified high-level and transuranic waste

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Fewell, M.A., Westinghouse Hanford

    1996-05-17

    The functions, requirements, interfaces, and architectures contained within the Functions and Requirements (F{ampersand}R) Document are based on the information currently contained within the TWRS Functions and Requirements database. The database also documents the set of technically defensible functions and requirements associated with the solidified waste interim storage mission.The F{ampersand}R Document provides a snapshot in time of the technical baseline for the project. The F{ampersand}R document is the product of functional analysis, requirements allocation and architectural structure definition. The technical baseline described in this document is traceable to the TWRS function 4.2.4.1, Interim Store Solidified Waste, and its related requirements, architecture, and interfaces.

  17. Microstructure of directionally solidified Ti-Fe eutectic alloy with low interstitial and high mechanical strength

    Science.gov (United States)

    Contieri, R. J.; Lopes, E. S. N.; Taquire de La Cruz, M.; Costa, A. M.; Afonso, C. R. M.; Caram, R.

    2011-10-01

    The performance of Ti alloys can be considerably enhanced by combining Ti and other elements, causing an eutectic transformation and thereby producing composites in situ from the liquid phase. This paper reports on the processing and characterization of a directionally solidified Ti-Fe eutectic alloy. Directional solidification at different growth rates was carried out in a setup that employs a water-cooled copper crucible combined with a voltaic electric arc moving through the sample. The results obtained show that a regular fiber-like eutectic structure was produced and the interphase spacing was found to be a function of the growth rate. Mechanical properties were measured using compression, microindentation and nanoindentation tests to determine the Vickers hardness, compressive strength and elastic modulus. Directionally solidified eutectic samples presented high values of compressive strength in the range of 1844-3000 MPa and ductility between 21.6 and 25.2%.

  18. Research on the compressive strength of basic magnesium salts and cyanide slag solidified body

    Science.gov (United States)

    Tu, Yubo; Han, Peiwei; Ye, Shufeng; Wei, Lianqi; Zhang, Xiaomeng; Fu, Guoyan; Yu, Bo

    2018-02-01

    The solidification of cyanide slag by using basic magnesium salts could reduce pollution and protect the environment. Experiments were carried out to investigate the effects of age, mixing amount of cyanide slag, water cement ratio and molar ratio of MgO to MgSO4 on the compressive strength of basic magnesium salts and cyanide slag solidified body in the present paper. It was found that compressive strength of solidified body increased with the increase of age, and decreased with the increase of mixing amount of cyanide slag and water cement ratio. The molar ratio of MgO to MgSO4 should be controlled in the range from 9 to 11 when the mixing amount of cyanide slag was larger than 80 mass%.

  19. Comparative analysis of mechanical characteristics of solidified concentrates from BWR system using Yugoslav and Italian cements

    International Nuclear Information System (INIS)

    Plecas, I.; Peric, A.; Drljaca, J.; Kostadinovic, A.

    1987-01-01

    In this paper, properties of Italian and Yugoslav cement mixture with BWR evaporation concentrates were compared, research was held upon fifteen samples, according to the adequate formulations. Samples were made in standard cube form, side 10 cm. Functional relationship between decreasing the compressive strength and amount of incorporated BWR concentrate cement mixture was developed. The results of research showed nearly the same mechanical properties of solidified BWR concentrate with Italian and Yugoslav cements. (author)

  20. Fabrication and tensile properties of rapidly solidified Cu-10wt. %Ni alloy. [Cu-10Ni

    Energy Technology Data Exchange (ETDEWEB)

    Baril, D; Angers, R; Baril, J [Dept. of Mining and Metallurgy, Laval Univ., Ste-Foy, Quebec (Canada)

    1992-10-15

    Cu-10wt.%Ni ribbons were produced by melt spinning and cut into small particles with a blade cutter mill. The powders were then hot consolidated to full density by hot pressing followed by hot extrusion. Tensile properties of the resulting pieces were measured. Cu-10wt.%Ni cast ingots were also hot extruded and mechanically tested to compare with the rapidly solidified alloy and to evaluate the possible benefits brought by the rapid solidification process.

  1. Leach testing of simulated ion-exchange resin waste solidified in cement

    International Nuclear Information System (INIS)

    Muurinen, A.K.; Uotila, P.I.; Ovaskainen, R.M.

    Leach tests were carried out on ion-exchange resins solidified in cement. Three product mixtures, two isotopes and four leachants at two temperatures, were tested. The increase of resin content increased the leaching of Cs-137; the effect of silix admixture was negligible. The type of the leachant has a stronger influence on Co-60 than on Cs-137. The increase of temperature usually also increased leaching. (author)

  2. The use of Nb in rapid solidified Al alloys and composites

    Energy Technology Data Exchange (ETDEWEB)

    Audebert, F., E-mail: metal@fi.uba.ar [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina); Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Department of Mechanical Engineering and Mathematical Sciences, Oxford Brookes University, Wheatley Campus, OX33 1HX Oxford (United Kingdom); Galano, M. [Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford (United Kingdom); Saporiti, F. [Advanced Materials Group, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, Ciudad de Buenos Aires 1063 (Argentina)

    2014-12-05

    Highlights: • The use of Nb in RS Al alloys and composites has been reviewed. • Nb was found to improve the GFA of rapid solidified Al–Fe and Al–Ni alloys. • Nb has higher effect in increasing the corrosion resistance than RE in Al–Fe alloys. • Nb improves the stability of the Al–Fe–Cr icosahedral phase. • Nb improves strength, ductility and toughness of nanoquasicrystalline Al matrix composites. - Abstract: The worldwide requirements for reducing the energy consumption and pollution have increased the demand of new and high performance lightweight materials. The development of nanostructured Al-based alloys and composites is a key direction towards solving this demand. High energy prices and decreased availability of some alloying elements open up the opportunity to use non-conventional elements in Al alloys and composites. In this work the application of Nb in rapid solidified Al-based alloys and Al alloys matrix composites is reviewed. New results that clarify the effect of Nb on rapid solidified Al alloys and composites are also presented. It is observed that Nb stabilises the icosahedral Al–Fe/Cr clusters, enhances the glass forming ability and shifts the icosahedral phase decomposition towards higher temperatures. Nb provides higher corrosion resistance with respect to the pure Al and Al–Fe–RE (RE: rare earth) alloys in the amorphous and crystalline states. The use of Nb as a reinforcement to produce new Al alloy matrix composites is explored. It is observed that Nb provides higher strength, ductility and toughness to the nanoquasicrystalline matrix composite. Nb appears as a new key element that can improve several properties in rapid solidified Al alloys and composites.

  3. Structure and transformation behaviour of a rapidly solidified Al-Y-Ni-Co-Pd alloy

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, D.V.; Inoue, A.

    2005-01-01

    An as-solidified structure and transformation behaviour on heating of the rapidly solidified Al-Y-Ni-Co-Pd alloy was studied by X-ray diffractometry (XRD), transmission electron microscopy (TEM), differential scanning and isothermal calorimetries. The Al-Y-Ni-Co-Pd ribbon samples have been produced by the melt spinning technique and heat treated using a differential scanning calorimeter (DSC). The addition of Pd to Al-Y-Ni-Co alloys caused disappearance of the supercooled liquid region as well as the formation of the highly dispersed primary α-Al nanoparticles about 3-7 nm in size homogeneously embedded in the glassy matrix upon solidification. An extremely high density of precipitates of the order of 10 24 m -3 is obtained. These particles start growing at the temperature below a glass-transition temperature. The results presented in this paper indicate that some of so-called 'marginal' glass-formers in as-solidified state are actually not glassy alloys with pre-existed nuclei but crystal-glassy nanocomposites

  4. Effect of tensile mean stress on fatigue behavior of single-crystal and directionally solidified superalloys

    Science.gov (United States)

    Kalluri, Sreeramesh; Mcgaw, Michael A.

    1990-01-01

    Two nickel base superalloys, single crystal PWA 1480 and directionally solidified MAR-M 246 + Hf, were studied in view of the potential usage of the former and usage of the latter as blade materials for the turbomachinery of the space shuttle main engine. The baseline zero mean stress (ZMS) fatigue life (FL) behavior of these superalloys was established, and then the effect of tensile mean stress (TMS) on their FL behavior was characterized. At room temperature these superalloys have lower ductilities and higher strengths than most polycrystalline engineering alloys. The cycle stress-strain response was thus nominally elastic in most of the fatigue tests. Therefore, a stress range based FL prediction approach was used to characterize both the ZMS and TMS fatigue data. In the past, several researchers have developed methods to account for the detrimental effect of tensile mean stress on the FL for polycrystalline engineering alloys. However, the applicability of these methods to single crystal and directionally solidified superalloys has not been established. In this study, these methods were applied to characterize the TMS fatigue data of single crystal PWA 1480 and directionally solidified MAR-M 246 + Hf and were found to be unsatisfactory. Therefore, a method of accounting for the TMS effect on FL, that is based on a technique proposed by Heidmann and Manson was developed to characterize the TMS fatigue data of these superalloys. Details of this method and its relationship to the conventionally used mean stress methods in FL prediction are discussed.

  5. Microstructure and orientation evolution in unidirectional solidified Al–Zn alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhongwei, E-mail: chzw@nwpu.edu.cn; Wang, Enyuan; Hao, Xiaolei

    2016-06-14

    Morphological instability and growth orientation evolution during unidirectional solidification of Al–Zn alloys with different pulling speeds were investigated by X-ray diffraction (XRD) and electron back-scatter diffraction (EBSD) in scanning electron microscope (SEM). The experimental results show that, as the pulling speed increases, the primary dendrite spacing becomes smaller gradually and dendrite trunks incline to the heat flow direction perfectly in unidirectional solidified Al–9.8 wt%Zn and Al–89 wt%Zn alloys. However, regardless of the pulling speed in unidirectional solidified Al–Zn alloys under fixed thermal gradient, the regular dendrites with <100> directions of primary trunks and secondary arms in 9.8 wt% Zn composition are replaced by <110> dendrites of primary trunks and secondary arms in 89 wt% Zn composition. In unidirectional solidified Al–32 wt% Zn alloy, cellular, fractal seaweed, and stabilized seaweed structures were observed at high pulling speeds. At a high pulling speed of 1000 µm/s, seaweed structures transform to the columnar dendrites with <110> trunks and <100> arms. The above orientation evolution can be attributed to low anisotropy of solid-liquid interface energy and the seaweed structure is responsible for isotropy of {111} planes.

  6. Bipolar resistive switching properties of Hf{sub 0.5}Zr{sub 0.5}O{sub 2} thin film for flexible memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhipeng; Zhu, Jun; Zhou, Yunxia; Liu, Xingpeng [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu (China)

    2018-01-15

    An Au/Ni/Hf{sub 0.5}Zr{sub 0.5}O{sub 2}/Au flexible memory device fabricated on a polyethylene terephthalate substrate was studied for flexible resistive random access memory applications. A typical bipolar resistive switching behavior was revealed with an OFF/ON ratio of approximately 15. The reproducibility and uniformity were investigated using 100 repetitive write/erase cycles. The retention property did not degrade for up to 5 x 10{sup 4} s, and the resistive switching properties did not degrade even under bending conditions, which indicated good mechanical flexibility. The current-voltage characteristics of the memory device show a Poole-Frenkel emission conduction mechanism in the high-voltage region in the high-resistance state, while in the low-voltage region, the Ohmic contact and space charge limit current responded to the low-resistance state and high-resistance state, respectively. Combined with the conductance mechanism, the resistive switching behavior is attributed to conductive filaments forming and rupturing due to oxygen vacancies migrating under the external driving electric field. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Effect of the substrate temperature on the microstructure and texture of Mg{sub 90}Zr{sub 10} (at.%) films deposited by sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Garces, Gerardo [Department of Physical Metallurgy, CENIM, CSIC, Av. De Gregorio del Amo 8, 28040 Madrid (Spain)]. E-mail: ggarces@cenim.csic.es; Landais, Stephan [Office National dEtudes et de Recherches Aerospatiales, ONERA, BP72-29 Avenue de la Division Leclerc F-92322 Chatillon, Paris (France); Adeva, Paloma [Department of Physical Metallurgy, CENIM, CSIC, Av. De Gregorio del Amo 8, 28040 Madrid (Spain)

    2006-11-30

    The microstructure of Mg{sub 90}Zr{sub 10} (at.%) films obtained by sputtering onto copper substrate at three different temperatures (180, 320 and 350 deg. C) has been studied. Films exhibited an intense (0 0 0 1) basal plane fibre texture with the fibre axis parallel to the growth direction. Their microstructure consisted of columnar grains growing from the copper substrate to the free surface which is typical of the zone II of the Movchan and Demchishin zone model developed for PVD materials. Nevertheless, the microstructure of films was dependent on the substrate temperature. The grain diameter increased as the substrate temperature was increased. Moreover, the dislocation density inside the grains as well as that piled-up forming sub-grain boundaries decreased as the deposition temperature increased. Although the film growth in zone II is controlled by surface diffusion the larger surface mobility of the atoms as the substrate temperature increased led to changes in the solubility of zirconium. At low substrate temperatures all zirconium was in solid solution. However, at 350 deg. C the formation of small zirconium particles occurred at grain boundaries.

  8. Table-like magnetocaloric effect in Gd{sub 56}Ni{sub 15}Al{sub 27}Zr{sub 2} alloy and its field independence feature

    Energy Technology Data Exchange (ETDEWEB)

    Agurgo Balfour, E.; Ma, Z.; Fu, H., E-mail: fuhao@uestc.edu.cn, E-mail: rockingsandstorm@163.com; Wang, L.; Luo, Y. [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Hadimani, R. L.; Jiles, D. C. [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Wang, S. F., E-mail: fuhao@uestc.edu.cn, E-mail: rockingsandstorm@163.com [North Electronic Device Research Institute, Beijing 100141 (China)

    2015-09-28

    In order to obtain “table-like” magnetocaloric effect (MCE), multiple-phase Gd{sub 56}Ni{sub 15}Al{sub 27}Zr{sub 2} alloy was prepared by arc-melting followed by suck-casting method. Powder x-ray diffraction and calorimetric measurements reveal that the sample contains both glassy and crystalline phases. The fraction of the glassy phase is about 62%, estimated from the heat enthalpy of the crystallization. The crystalline phases, Gd{sub 2}Al and GdNiAl further broadened the relatively wider magnetic entropy change (−ΔS{sub M}) peak of the amorphous phase, which resulted in the table-like MCE over a maximum temperature range of 52.5 K to 77.5 K. The plateau feature of the MCE was found to be nearly independent of the applied magnetic field from 3 T to 5 T. The maximum −ΔS{sub M} value of the MCE platforms is 6.0 J/kg K under applied magnetic field change of 5 T. Below 3 T, the field independence of the table-like feature disappears. The relatively large constant values of −ΔS{sub M} for the respective applied magnetic fields have promising applications in magnetic refrigeration using regenerative Ericsson cycle.

  9. Zr{sub 2}N{sub 2}Se. The first zirconium(IV) nitride selenide by the oxidation of zirconium(III) nitride with selenium

    Energy Technology Data Exchange (ETDEWEB)

    Lissner, Falk; Hack, Bettina; Schleid, Thomas [Institute for Inorganic Chemistry, University of Stuttgart (Germany); Lerch, Martin [Institute for Chemistry, Technical University of Berlin (Germany)

    2012-08-15

    The oxidation of zirconium(III) nitride (ZrN) with suitable amounts of selenium (Se) in the presence of sodium chloride (NaCl) as flux yields small yellow brownish platelets of the first zirconium(IV) nitride selenide with the composition Zr{sub 2}N{sub 2}Se. The new compound crystallizes in the hexagonal space group P6{sub 3}/mmc (no. 194) with a = 363.98(2) pm, c = 1316.41(9) pm (c/a = 3.617) and two formula units per unit cell. The crystallographically unique Zr{sup 4+} cations are surrounded by three selenide and four nitride anions in the shape of a capped trigonal antiprism. The Se{sup 2-} anions are coordinated by six Zr{sup 4+} cations as trigonal prism and the N{sup 3-} anions reside in tetrahedral surrounding of Zr{sup 4+} cations. These [NZr{sub 4}]{sup 13+} tetrahedra become interconnected via three edges each to form {sup 2}{sub ∞}{[(NZr_4_/_4)_2]"2"+} double layers parallel to the (001) plane, which are held together by monolayers of Se{sup 2-} anions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. TiNiSn and Zr{sub 0.5}Hf{sub 0.5}NiSn superlattices for thermoelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Tino; Jakob, Gerhard [Institut fuer Physik, Universitaet Mainz, 55099 Mainz (Germany); Schwall, Michael; Kozina, Xeniya; Balke, Benjamin; Felser, Claudia [Institut fuer Analytische und Anorganische Chemie, Universitaet Mainz, 55099 Mainz (Germany); Populoh, Sascha; Weidenkaff, Anke [EMPA, Ueberlandstrasse 129, 8600 Duebendorf (Switzerland)

    2012-07-01

    In order to increase the attractiveness of thermoelectric devices, their efficiency must be increased. Beside others, the properties of the thermoelectric material can be improved. That can be achieved by either increasing Seebeck coefficient or conductivity or by a depressed thermal conductivity along the thermal gradient. For thin films, superlattices or multilayers can be used to lower the cross plane thermal conductivity. As a bottom up approach, artificially layered films with a periodicity of about 5-6 nm are assumed to generate the most phonon scattering at the interfaces. If electrical properties remain unchanged or less effected, the thermoelectric efficiency is enhanced. Semiconducting Half-Heuslers are well studied thermoelectric bulk materials. Among others, TiNiSn and Zr{sub 0.5}Hf{sub 0.5}NiSn are potential candidates. Essentially, their similar lattice constants enable epitaxial layers on top of each other. Furthermore, varied atomic masses of Ti, Zr and Hf generate the aspired alternating mass distribution. By rotating the substrate in between simultaneously burning cathodes, significant film thicknesses can be achieved by sputter deposition.

  11. Enhanced dielectric nonlinearity in epitaxial Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Chunrui, E-mail: chunrui.ma@gmail.com, E-mail: jwu@ku.edu; Wu, Judy, E-mail: chunrui.ma@gmail.com, E-mail: jwu@ku.edu [Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas, 66045 (United States); Ma, Beihai [Energy Systems Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Mi, Shao-Bo [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China); Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Liu, Ming [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi' an Jiaotong University, Xi' an 710049 (China)

    2014-04-21

    High quality c-axis oriented epitaxial Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub 3} films were fabricated using pulsed laser deposition on (001) LaAlO{sub 3} substrates with conductive LaNiO{sub 3} buffers. Besides confirmation of the in-plane and out-of-plane orientations using X-ray diffraction, transmission electron microscopy study has revealed columnar structure across the film thickness with column width around 100 nm. Characterization of ferroelectric properties was carried out in comparison with polycrystalline Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub 3} films to extract the effect of epitaxial growth. It is found that the ratio between the irreversible Rayleigh parameter and reversible parameter increased up to 0.028 cm/kV at 1 kHz on epitaxial samples, which is more than twice of that on their polycrystalline counterparts. While this ratio decreased to 0.022 cm/kV with increasing frequency to100 kHz, a much less frequency dependence was observed as compared to the polycrystalline case. The epitaxial Pb{sub 0.92}La{sub 0.08}Zr{sub 0.52}Ti{sub 0.48}O{sub 3} films exhibited a higher mobility of domain wall and the higher extrinsic contribution to the dielectric properties, as well as reduced density of defects, indicating that it is promising for tunable and low power consumption devices.

  12. Effect of zirconium purity on the glass-forming-ability and notch toughness of Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Laura M. [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA (United States); Hofmann, Douglas C. [Materials Development and Manufacturing Technology Group, NASA Jet Propulsion Laboratory/California Institute of Technology, MS 18-105, 4800 Oak Grove Dr. Pasadena, CA 91109 (United States); Vecchio, Kenneth S., E-mail: kvecchio@ucsd.edu [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA (United States)

    2016-09-30

    The effect of substituting standard grade zirconium lump (99.8% excluding up to 4% hafnium) for high purity zirconium crystal bar (99.5%) in a Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7} bulk metallic glass (BMG) is examined. The final hafnium content in the BMG specimens was found to range from 0 to 0.44 at%. Introducing low purity zirconium significantly decreased the glass-forming-ability and reduced the notch toughness of the BMG. In contrast, when adding high purity hafnium to Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7} made with high purity zirconium, no significant change in the glass-forming-ability or toughness was observed. This suggests that the introduction of low purity zirconium in BMGs creates a more complex response than a simple addition of hafnium. It is likely that other impurities in the material, such as oxygen, play a role in the complex crystallization kinetics and change in mechanical properties. The notch toughness was measured through four-point-bend tests, which showed a decrease in notch toughness from an average of ~53 MPa m{sup 1/2} for the high purity samples to an average of ~29 MPa m{sup 1/2} with full substitution of low purity zirconium. A similar decrease in glass-forming-ability and toughness is observed in commercially synthesized high purity Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7}. The large scale commercial process is expected to introduced some unintentional impurities, which decrease the properties of the BMG in the same way as the lower purity elements. Lastly, Weibull statistics are used to provide an analysis of variability in toughness for both ingots synthesized in a small laboratory arc-melter and those synthesized commercially.

  13. Distribution of impurity states and charge transport in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuanfeng; Makongo, Julien P.A. [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Page, Alexander [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Sahoo, Pranati [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Uher, Ctirad [Department of Physics, University of Michigan, Ann Arbor, MI 48109 (United States); Stokes, Kevin [The Advanced Materials Research Institute, Department of Physics, University of New Orleans, New Orleans, LA 70148 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@umich.edu [Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-02-15

    Energy filtering of charge carriers in a semiconducting matrix using atomically coherent nanostructures can lead to a significant improvement of the thermoelectric figure of merit of the resulting composite. In this work, several half-Heusler/full-Heusler (HH/FH) nanocomposites with general compositions Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} (0≤x≤0.15 and y=0.005, 0.01 and 0.025) were synthesized in order to investigate the behavior of extrinsic carriers at the HH/FH interfaces. Electronic transport data showed that energy filtering of carriers at the HH/FH interfaces in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} samples strongly depends on the doping level (y value) as well as the energy levels occupied by impurity states in the samples. For example, it was found that carrier filtering at HH/FH interfaces is negligible in Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 1−y}Sb{sub y} (y=0.01 and 0.025) composites where donor states originating from Sb dopant dominate electronic conduction. However, we observed a drastic decrease in the effective carrier density upon introduction of HH/FH interfaces for the mechanically alloyed Zr{sub 0.25}Hf{sub 0.75}Ni{sub 1+x}Sn{sub 0.995}Sb{sub 0.005} samples where donor states from unintentional Fe impurities contribute the largest fraction of conduction electrons. This work demonstrates the ability to synergistically integrate the concepts of doping and energy filtering through nanostructuring for the optimization of electronic transport in semiconductors. - Graphical abstract: Electronic transport in semiconducting half-Heusler (HH) matrices containing full-Heusler (FH) nanoinclusions strongly depends on the energy distribution of impurity states within the HH matrix with respect to the magnitude of the potential energy barrier at the HH/FH interfaces. - Highlights: • Coherent nanostructures enhanced thermoelectric behavior of half-Heusler alloys. • Nanostructures act as energy filter of

  14. Magnetic susceptibility and zone structure of solid solutions in ZrC-NbN and Zrsub(0.5)Nbsub(0.5)Csub(x)Nsub(1-x) systems

    International Nuclear Information System (INIS)

    Gusev, A.I.; Dubrovskaya, L.B.; Shvejkin, G.P.

    1975-01-01

    Face-centered cubic solid solutions in the systems ZrC-NbN and Zrsub(0.5)Nbsub(0.5)Csub(x)Nsub(1-x) arranged to the mutual substitution type have been synthesized. The concentration and temperature dependences of the magnetic susceptibility have been studied. The extremal nature of the concentrational dependences of the magnetic susceptibility and the magnetic susceptibility temperature coefficient in the system ZrC-NbN is determined. The possibility is shown of considering the stoichiometric carbides and nitrides of the transition metals of the same period within the framework of the model of a single zone structure

  15. Hardness and microstructural characteristics of rapidly solidified Al-8-16 wt.%Si alloys

    International Nuclear Information System (INIS)

    Uzun, O.; Karaaslan, T.; Gogebakan, M.; Keskin, M.

    2004-01-01

    Al-Si alloys with nominal composition of Al-8 wt.%Si, Al-12 wt.%Si, and Al-16 wt.%Si were rapidly solidified by using melt-spinning technique to examine the influence of the cooling rate/conditions on microstructure and mechanical properties. The microstructures of the rapidly solidified ribbons and ingot samples were investigated by the optical microscopy, electron microscopy and X-ray diffraction (XRD) techniques. The results showed that the structures of all melt-spun ribbons were completely composed of finely dispersed α-Al and eutectic Si phase, and primary silicon was not observed. The XRD analysis indicated that the solubility of Si in the α-Al matrix was greatly increased with rapid solidification. Additionally, mechanical properties of both conventionally cast (ingot) and melt-spun ribbons were examined by using Vickers indenter for one applied load (0.098 N). The hardness values of the melt-spun ribbons were about three times higher than those of ingot counterparts. The high hardness of the rapidly solidified state can be attributed to the supersaturated solid solutions. Besides, hardness values with different applied loads were measured for melt-spun ribbons. The results indicated that Vickers hardness values (H v ) of the ribbons depended on the applied load. Applying the concept of Hays-Kendall, the load independent hardness values were calculated as 694.0, 982.8 and 1186.8 MN/m 2 for Al-8 wt.%Si, Al-12 wt.%Si and Al-16 wt.%Si, respectively

  16. Development and characterization of solidified forms for high-level wastes: 1978. Annual report

    International Nuclear Information System (INIS)

    Ross, W.A.; Mendel, J.E.

    1979-12-01

    Development and characterization of solidified high-level waste forms are directed at determining both process properties and long-term behaviors of various solidified high-level waste forms in aqueous, thermal, and radiation environments. Waste glass properties measured as a function of composition were melt viscosity, melt electrical conductivity, devitrification, and chemical durability. The alkali metals were found to have the greatest effect upon glass properties. Titanium caused a slight decrease in viscosity and a significant increase in chemical durability in acidic solutions (pH-4). Aluminum, nickel and iron were all found to increase the formation of nickel-ferrite spinel crystals in the glass. Four multibarrier advanced waste forms were produced on a one-liter scale with simulated waste and characterized. Glass marbles encapsulated in a vacuum-cast lead alloy provided improved inertness with a minimal increase in technological complexity. Supercalcine spheres exhibited excellent inertness when coated with pyrolytic carbon and alumina and put in a metal matrix, but the processing requirements are quite complex. Tests on simulated and actual high-level waste glasses continue to suggest that thermal devitrification has a relatively small effect upon mechanical and chemical durabilities. Tests on the effects radiation has upon waste forms also continue to show changes to be relatively insignificant. Effects caused by decay of actinides can be estimated to saturate at near 10 19 alpha-events/cm 3 in homogeneous solids. Actually, in solidified waste forms the effects are usually observed around certain crystals as radiation causes amorphization and swelling of th crystals

  17. Chemical characterization, leach, and adsorption studies of solidified low-level wastes

    International Nuclear Information System (INIS)

    Walter, M.B.; Serne, R.J.; Jones, T.L.; McLaurine, S.B.

    1986-12-01

    Laboratory and field leaching experiments are beig conducted by Pacific Northwest Laboratory (PNL) to investigate the performance of solidified low-level nuclear waste in a typical, arid, near-surface disposal site. Under PNL's Special Waste Form Lysimeters-Arid Program, a field test facility was constructed to monitor the leaching of commercial solidified waste. Laboratory experiments were conducted to investigate the leaching and adsorption characteristics of the waste forms in contact with soil. Liquid radioactive wastes solidified in cement, vinyl ester-styrene, and bitumen were obtained from commercial boiling water and pressurized water reactors, and buried in a field leaching facility on the Hanford site in southeastern Washington State. Batch leaching, soil column adsorption, and soil/waste form column experiments were conducted in the laboratory, using small-scale cement waste forms and Hanford site ground water. The purpose of these experiments is to evaluate the ability of laboratory leaching tests to predict leaching under actual field conditions and to determine which mechanisms (i.e., diffusion, solubility, adsorption) actually control the concentration of radionuclides in the soil surrounding the waste form. Chemical and radionuclide analyses performed on samples collected from the field and laboratory experiments indicate strong adsorption of /sup 134,137/Cs and 85 Sr onto the Hanford site sediment. Small amounts of 60 Co are leached from the waste forms as very mobile species. Some 60 Co migrated through the soil at the same rate as water. Chemical constituents present in the reactor waste streams also found at elevated levels in the field and laboratory leachates include sodium, sulfate, magnesium, and nitrate. Plausible solid phases that could be controlling some of the chemical and radionuclide concentrations in the leachate were identified using the MINTEQ geochemical computer code

  18. Photoluminescence properties of ‘red’ emitting La{sub 2}Zr{sub 2}O{sub 7}:Eu pyrochlore ceramics for potential phosphor application

    Energy Technology Data Exchange (ETDEWEB)

    Mohapatra, M., E-mail: manojm@barc.gov.in; Rajeswari, B.; Hon, N.S.; Kadam, R.M.; Natarajan, V.

    2015-10-15

    Lanthanum zirconate (La{sub 2}Zr{sub 2}O{sub 7}=LZO) pyrochlores doped with varying concentrations of Eu were synthesized using a low temperature gel-combustion synthesis route and characterized using X-ray diffraction, scanning electron microscopic and photoluminescence techniques. The final annealing temperature of the system could be brought down to 700 °C to produce a single phase compound. In addition, the optimum activator ion concentration for maximum luminescence yield was evaluated for the system. The site occupancy for the Eu ions was also investigated which suggested that at 500 °C, the ions were on the surface of the LZO host and later diffused into the lattice and replaced the La{sup 3+} ions on annealing at 700 °C 5 h. However, due to difference in the ionic radii, the doped RE ions were of the inversion center forming a D{sub 2d} symmetry around them. For the first time the radiative properties and the commercial utility of the LZO system have been investigated. These parameters were used to get an idea about the M–L bond covalency in the system. The radiative properties suggested the system can be used as a potential ‘red’ emitting phosphor. - Highlights: • Synthesis of lanthanum zirconate pyrochlores doped with Eu using gel-combustion route. • Optimization of dopant ion concentration and annealing temperature and evaluation of its local site symmetry. • Evaluation of various photo-physical properties for the Eu-LZO system to investigate the M–L bond covalency. • Investigation of the commercial utility of the system by calculating the color coordinates. • Comparison of the emission properties with commercial sample.

  19. Growth of thick La{sub 2}Zr{sub 2}O{sub 7} buffer layers for coated conductors by polymer-assisted chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin, E-mail: xzhang@my.swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Electrical Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Yong, E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Xia, Yudong [State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Guo, Chunsheng [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW (Australia); Zhang, Yong [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity and New Energy Center (SNEC), Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, Han [Department of Physics, Peking University, Beijing 100871 (China)

    2015-06-15

    Highlights: • We develops a low-cost and high-efficient technology of fabricating LZO buffer layers. • Sufficient thickness LZO buffer layers have been obtained on NiW (2 0 0) alloy substrate. • Highly biaxially textured YBCO thin film has been deposited on LZO/NiW. - Abstract: La{sub 2}Zr{sub 2}O{sub 7} (LZO) epitaxial films have been deposited on LaAlO{sub 3} (LAO) (1 0 0) single-crystal surface and bi-axially textured NiW (2 0 0) alloy substrate by polymer-assisted chemical solution deposition, and afterwards studied with XRD, SEM and AFM approaches. Highly in-plane and out-of-plane oriented, dense, smooth, crack free and with a sufficient thickness (>240 nm) LZO buffer layers have been obtained on LAO (1 0 0) single-crystal surface; The films deposited on NiW (2 0 0) alloy substrate are also found with high degree in-plane and out-of-plane texturing, good density with pin-hole-free, micro-crack-free nature and a thickness of 300 nm. Highly epitaxial 500 nm thick YBa{sub 2}Cu{sub 3}O{sub 7−x} (YBCO) thin film exhibits the self-field critical current density (Jc) reached 1.3 MA/cm{sup 2} at 77 K .These results demonstrate the LZO epi-films obtained with current techniques have potential to be a buffer layer for REBCO coated conductors.

  20. Solidification structure and dispersoids in rapidly solidified Ti-Al-Sn-Zr-Er-B alloys

    International Nuclear Information System (INIS)

    Rowe, R.G.; Broderick, T.F.; Koch, E.F.; Froes, F.H.

    1986-01-01

    The microstructure of melt extracted and melt spun titanium alloys containing erbium and boron revealed a duplex solidification structure of columnar grains leading to equiaxed and dendritic structures near the free surface of melt extracted and melt spun alloys. The solidification structure was revealed by apparent boride segregation to cellular, interdendritic and grain boundaries. Precipitation of needle or lath-like TiB particles occurred adjacent to Er/sub 2/O/sub 3/ dispesoid particles in as-rapidly solidified ribbon

  1. Determination of performance criteria for high-level solidified nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Heckman, R.A.; Holdsworth, T.

    1979-05-07

    To minimize radiological risk from the operation of a waste management system, performance limits on volatilization, particulate dispersion, and dissolution characteristics of solidified high level waste must be specified. The results show clearly that the pre-emplacement environs are more limiting in establishing the waste form performance criteria than the post-emplacement environs. Absolute values of expected risk are very sensitive to modeling assumptions. The transportation and interim storage operations appear to be most limiting in determining the performance characteristics required. The expected values of risk do not rely upon the repositories remaining intact over the potentially hazardous lifetime of the waste.

  2. The influence of interfacial energies and gravitational levels on the directionally solidified structures in hypermonotectic alloys

    Science.gov (United States)

    Andrews, J. B.; Curreri, P. A.; Sandlin, A. C.

    1988-01-01

    Various Cu-Pb-Al alloys were directionally solidified under 1-g conditions and alternating high-g/low-g conditions (achieved using NSAS's KC-135 aircraft) as a means of studying the influence of interfacial energies and gravitational levels on the resulting microstructures. Directional solidification of low Al content alloys was found to result in samples with coarser more irregular microstructures than in alloys with high Al contents under all the gravity conditions considered. Structures are correlated with interfacial energies, growth rates, and gravitational levels.

  3. Determination of performance criteria for high-level solidified nuclear waste

    International Nuclear Information System (INIS)

    Heckman, R.A.; Holdsworth, T.

    1979-01-01

    To minimize radiological risk from the operation of a waste management system, performance limits on volatilization, particulate dispersion, and dissolution characteristics of solidified high level waste must be specified. The results show clearly that the pre-emplacement environs are more limiting in establishing the waste form performance criteria than the post-emplacement environs. Absolute values of expected risk are very sensitive to modeling assumptions. The transportation and interim storage operations appear to be most limiting in determining the performance characteristics required. The expected values of risk do not rely upon the repositories remaining intact over the potentially hazardous lifetime of the waste

  4. Directionally Solidified Aluminum - 7 wt% Silicon Alloys: Comparison of Earth and International Space Station Processed Samples

    Science.gov (United States)

    Grugel, Richard N,; Tewari, Surendra; Rajamure, R. S.; Erdman, Robert; Poirier, David

    2012-01-01

    Primary dendrite arm spacings of Al-7 wt% Si alloy directionally solidified in low gravity environment of space (MICAST-6 and MICAST-7: Thermal gradient approx. 19 to 26 K/cm, Growth speeds varying from 5 to 50 microns/s show good agreement with the Hunt-Lu model. Primary dendrite trunk diameters of the ISS processed samples show a good fit with a simple analytical model based on Kirkwood s approach, proposed here. Natural convection, a) decreases primary dendrite arm spacing. b) appears to increase primary dendrite trunk diameter.

  5. Performance demonstration program plan for RCRA constituent analysis of solidified wastes

    International Nuclear Information System (INIS)

    1995-06-01

    Performance Demonstration Programs (PDPS) are designed to help ensure compliance with the Quality Assurance Objectives (QAOs) for the Waste Isolation Pilot Plant (WIPP). The PDPs are intended for use by the Department of Energy (DOE) Carlsbad Area Office (CAO) to assess and approve the laboratories and other measurement facilities supplying services for the characterization of WIPP TRU waste. The PDPs may also be used by CAO in qualifying laboratories proposing to supply additional analytical services that are required for other than waste characterization, such as WIPP site operations. The purpose of this PDP is to test laboratory performance for the analysis of solidified waste samples for TRU waste characterization. This performance will be demonstrated by the successful analysis of blind audit samples of simulated, solidified TRU waste according to the criteria established in this plan. Blind audit samples (hereinafter referred to as PDP samples) will be used as an independent means to assess laboratory performance regarding compliance with the QAOs. The concentration of analytes in the PDP samples will address levels of regulatory concern and will encompass the range of concentrations anticipated in actual waste characterization samples. Analyses that are required by the WIPP to demonstrate compliance with various regulatory requirements and which are included in the PDP must be performed by laboratories that demonstrate acceptable performance in the PDP. These analyses are referred to as WIPP analyses and the samples on which they are performed are referred to as WIPP samples for the balance of this document

  6. Cryogenic EBSD reveals structure of directionally solidified ice–polymer composite

    International Nuclear Information System (INIS)

    Donius, Amalie E.; Obbard, Rachel W.; Burger, Joan N.; Hunger, Philipp M.; Baker, Ian; Doherty, Roger D.; Wegst, Ulrike G.K.

    2014-01-01

    Despite considerable research efforts on directionally solidified or freeze-cast materials in recent years, little fundamental knowledge has been gained that links model with experiment. In this contribution, the cryogenic characterization of directionally solidified polymer solutions illustrates, how powerful cryo-scanning electron microscopy combined with electron backscatter diffraction is for the structural characterization of ice–polymer composite materials. Under controlled sublimation, the freeze-cast polymer scaffold structure is revealed and imaged with secondary electrons. Electron backscatter diffraction fabric analysis shows that the ice crystals, which template the polymer scaffold and create the lamellar structure, have a-axes oriented parallel to the direction of solidification and the c-axes perpendicular to it. These results indicate the great potential of both cryo-scanning electron microscopy and cryo-electron backscatter diffraction in gaining fundamental knowledge of structure–property–processing correlations. - Highlights: • Cryo-SEM of freeze-cast polymer solution reveals an ice-templated structure. • Cryo-EBSD reveals the ice crystal a-axis to parallel the solidification direction. • The honeycomb-like polymer phase favors columnar ridges only on one side. • Combining cryo-SEM with EBSD links solidification theory with experiment

  7. EPICOR-II: a field leaching test of solidified radioactively loaded ion exchange resin

    International Nuclear Information System (INIS)

    Davis, E.C.; Marshall, D.S.; Todd, R.A.; Craig, P.M.

    1986-08-01

    As part of an ongoing research program investigating the disposal of radioactive solid wastes in the environment' the Oak Ridge National Laboratory (ORNL) is participating with Argonne National Laboratory, the Idaho National Engineering Laboratory, and the Nuclear Regulatory Commission in a study of the leachability of solidified EPICOR-II ion-exchange resin under simulated disposal conditions. To simulate disposal, a group of five 2-m 3 soil lysimeters has been installed in Solid Waste Storage Area Six at ORNL, with each lysimeter containing a small sample of solidified resin at its center. Two solidification techniques are being investigated: a Portland cement and a vinyl ester-styrene treatment. During construction, soil moisture temperature cells were placed in each lysimeter, along with five porous ceramic tubes for sampling water near the waste source. A meteorological station was set up at the study site to monitor climatic conditions (primarily precipitation and air temperature), and a data acquisition system was installed to keep daily records of these meteorological parameters as well as lysimeter soil moisture and temperature conditions. This report documents the first year of the long-term field study and includes discussions of lysimeter installation, calibration of soil moisture probes, installation of the site meteorological station, and the results of the first-quarter sampling for radionuclides in lysimeter leachate. In addition, the data collection and processing system developed for this study is documented, and the results of the first three months of data collection are summarized in Appendix D

  8. Study on metal material corrosion behavior of packaging of cement solidified form

    International Nuclear Information System (INIS)

    He Zhouguo; Lin Meiqiong; Fan Xianhua

    1997-01-01

    The corrosion behavior of A3 carbon steel is studied by the specimens that are exposed to atmosphere, embedded in cement solidified form or immersed in corrosion liquid. The corrosion rate is determined by mass change of the specimens. In order to compare the corrosion resistant performance of various coatings, the specimens painted with various material such as epoxide resin, propionic acid resin, propane ether resin and Ti-white paint are tested. The results of the tests show that corrosion rate of A3 carbon steel is less than 10 -3 mm·a -1 in the atmosphere and the cement solidified from, less than 0.1 mm·a -1 in the corrosion liquids, and pH value in the corrosion liquids also affect the corrosion rate of A3 carbon steel. The corrosion resistant performance of Ti-white paint is better than that of other paints. So, A3 carbon steel as packaging material can meet the requirements during storage

  9. Microstructural development in a rapidly solidified Al-Fe-V-Si alloy

    International Nuclear Information System (INIS)

    Park, W.J.; Baek, E.R.; Lee, Sunghak; Kim, N.J.

    1991-01-01

    TEM is used to investigate microstructural development in a rapidly solidified Al-Fe-V-Si alloy. The as-cast microstructure of a rapidly solidified Al-Fe-V-Si alloy was found to vary depending on casting conditions and also through the thickness of ribbon. For completely Zone A ribbon, intercellular phase consists of a microquasi-crystalline phase, while for the Zone A and Zone B mixed ribbon, it consists of a silicide phase. In either case, formation of globular particles of a cluster microquasi-crystalline phase is observed near the air side of the ribbon. Annealing study shows significant differences in the final microstructure depending on the initial status of the ribbon. Completely Zone A ribbon, whose microstructure is composed of a microquasi-crystalline phase, results in a very coarse microstructure after annealing as compared to the Zone A and Zone B mixed ribbon. This result has important implications for the development of high-performance elevated-temperature Al alloys. 12 refs

  10. Experimental Investigation of Closed Porosity of Inorganic Solidified Foam Designed to Prevent Coal Fires

    Directory of Open Access Journals (Sweden)

    Yi Lu

    2015-01-01

    Full Text Available In order to overcome the deficiency of the existing fire control technology and control coal spontaneous combustion by sealing air leakages in coal mines, inorganic solidified foam (ISF with high closed porosity was developed. The effect of sodium dodecyl sulfate (SDS concentration on the porosity of the foams was investigated. The results showed that the optimized closed porosity of the solidified foam was 38.65 wt.% for an SDS concentration of approximately 7.4×10-3 mol/L. Based on observations of the microstructure of the pore walls after solidification, it was inferred that an equilibrium between the hydration process and the drainage process existed. Therefore, the ISF was improved using three different systems. Gelatin can increase the viscosity of the continuous phase to form a viscoelastic film around the air cells, and the SDS + gelatin system can create a mixed surfactant layer at gas/liquid interfaces. The accelerator (AC accelerates the hydration process and coagulation of the pore walls before the end of drainage. The mixed SDS + gelatin + AC systems produced an ISF with a total porosity of 79.89% and a closed porosity of 66.89%, which verified the proposed stabilization mechanism.

  11. Directionally solidified Al2O3/GAP eutectic ceramics by micro-pulling-down method

    Science.gov (United States)

    Cao, Xue; Su, Haijun; Guo, Fengwei; Tan, Xi; Cao, Lamei

    2016-11-01

    We reported a novel route to prepare directionally solidified (DS) Al2O3/GAP eutectic ceramics by micro-pulling-down (μ-PD) method. The eutectic crystallizations, microstructure characters and evolutions, and their mechanical properties were investigated in detail. The results showed that the Al2O3/GAP eutectic composites can be successfully fabricated through μ-PD method, possessed smooth surface, full density and large crystal size (the maximal size: φ90 mm × 20 mm). At the process of Diameter, the as-solidified Al2O3/GAP eutectic presented a combination of "Chinese script" and elongated colony microstructure with complex regular structure. Inside the colonies, the rod-type or lamellar-type eutectic microstructures with ultra-fine GAP surrounded by the Al2O3 matrix were observed. At an appropriate solidificational rate, the binary eutectic exhibited a typical DS irregular eutectic structure of "chinese script" consisting of interpenetrating network of α-Al2O3 and GAP phases without any other phases. Therefore, the interphase spacing was refined to 1-2 µm and the irregular microstructure led to an outstanding vickers hardness of 17.04 GPa and fracture toughness of 6.3 MPa × m1/2 at room temperature.

  12. Study on the barrier performance of molten solidified waste (I). Review of the performance assessment research

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Toshikatsu; Sakamoto, Yoshiaki; Nakayama, Shinichi; Yamaguchi, Tetsuji; Ogawa, Hiromichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-02-01

    Application of melting technique is thought as one of the effective methods to treatment of the waste from the view point of its homogeneity and waste volume reduction. Solidified products by melting are expected as potential candidates of engineered barrier in a repository due to the good properties for their stabilization of radionuclides and hazardous elements. However, the methodology of performance evaluation has not been estimated so far. In this report, a literature survey on the properties of molten solidified waste was performed. It is clarified that the leachability of waste elements such as Co or Sr in molten waste form would be controlled by the corrosion behaviors of iron or silica which are the matrix elements of the waste form. While, no investigations into the durability of waste form have performed so far. Also noticed that the research items on performance evaluation such as the leachability for long-lived radionuclides and durability of waste form would be necessary for the long-term barrier assessment on the disposal. (author)

  13. Testing of variables which affect stablity of cement solidified low-level waste

    International Nuclear Information System (INIS)

    Boris, G.F.

    1989-01-01

    This paper describes the test program undertaken to investigate variables which could affect the stability of cement solidified low-level waste and to evaluate the effect of these variables on certain tests prescribed in the Technical Position on Waste Form. The majority of the testing was performed on solidified undepleted bead resin, however, six additional waste types, suggested by the NRC, were tested. The tested variables included waste loading, immersion duration, depletion level, ambient cure duration, curing environment, immersion medium and waste type. Of these, lower waste loadings, longer ambient cures prior to testing and immersion in demineralized water versus simulated sea water and potable water resulted in higher compressive strengths for bead resin samples. Immersion times longer than 90 days did not affect the resin samples. Compressive strengths for other waste types varied depending upon the waste. The strengths of all waste types exceeded the minimum criterion by at least a factor of four, up to a factor of forty. The higher waste loadings exhibit strengths less than the lower waste loadings

  14. Cryogenic EBSD reveals structure of directionally solidified ice–polymer composite

    Energy Technology Data Exchange (ETDEWEB)

    Donius, Amalie E., E-mail: amalie.donius@gmail.com [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 (United States); Department of Materials Science and Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Obbard, Rachel W., E-mail: Rachel.W.Obbard@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 (United States); Burger, Joan N., E-mail: ridge.of.the.ancients@gmail.com [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 (United States); Department of Materials Science and Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Hunger, Philipp M., E-mail: philipp.m.hunger@gmail.com [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 (United States); Department of Materials Science and Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Baker, Ian, E-mail: Ian.Baker@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 (United States); Doherty, Roger D., E-mail: dohertrd@drexel.edu [Department of Materials Science and Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Wegst, Ulrike G.K., E-mail: ulrike.wegst@dartmouth.edu [Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755 (United States)

    2014-07-01

    Despite considerable research efforts on directionally solidified or freeze-cast materials in recent years, little fundamental knowledge has been gained that links model with experiment. In this contribution, the cryogenic characterization of directionally solidified polymer solutions illustrates, how powerful cryo-scanning electron microscopy combined with electron backscatter diffraction is for the structural characterization of ice–polymer composite materials. Under controlled sublimation, the freeze-cast polymer scaffold structure is revealed and imaged with secondary electrons. Electron backscatter diffraction fabric analysis shows that the ice crystals, which template the polymer scaffold and create the lamellar structure, have a-axes oriented parallel to the direction of solidification and the c-axes perpendicular to it. These results indicate the great potential of both cryo-scanning electron microscopy and cryo-electron backscatter diffraction in gaining fundamental knowledge of structure–property–processing correlations. - Highlights: • Cryo-SEM of freeze-cast polymer solution reveals an ice-templated structure. • Cryo-EBSD reveals the ice crystal a-axis to parallel the solidification direction. • The honeycomb-like polymer phase favors columnar ridges only on one side. • Combining cryo-SEM with EBSD links solidification theory with experiment.

  15. Detection of free liquid in cement-solidified radioactive waste drums using computed tomography

    International Nuclear Information System (INIS)

    Steude, J.S.; Tonner, P.D.

    1991-01-01

    Acceptance criteria for disposal of radioactive waste drums require that the cement-solidified material in the drum contain minimal free liquid after the cement has hardened. Free liquid is to be avoided because it may corrode the drum, escape and cause environmental contamination. The DOE has requested that a nondestructive evaluation method be developed to detect free liquid in quantities in excess of 0.5% by volume. This corresponds to about 1 liter in a standard 208 liter (55 gallon) drum. In this study, the detection of volumes of free liquid in a 57 cm (2 ft.) diameter cement-solidified drum is demonstrated using high-energy X-ray computed tomography (CT0. In this paper it is shown that liquid concentrations of simulated radioactive waste inside glass tubes imbedded in cement can easily be detected, even for tubes with inner diameters less than 2 mm (0.08 in.). Furthermore, it is demonstrated that tubes containing water and liquid concentrations of simulated radioactive waste can be distinguished from tubes of the same size containing air. The CT images were obtained at a rate of about 6 minutes per slice on a commercially available CT system using a 9 MeV linear accelerator source

  16. Experimental Study and Application of Inorganic Solidified Foam Filling Material for Coal Mines

    Directory of Open Access Journals (Sweden)

    Hu Wen

    2017-01-01

    Full Text Available Spontaneous combustion of residual coal in a gob due to air leakage poses a major risk to mining safety. Building an airtight wall is an effective measure for controlling air leakage. A new type of inorganic solidified foam-filled material was developed and its physical and chemical properties were analyzed experimentally. The compressive strength of this material increased with the amount of sulphoaluminate cement. With an increasing water–cement ratio, the initial setting time was gradually extended while the final setting time firstly shortened and then extended. The change in compressive strength had the opposite tendency. Additionally, as the foam expansion ratio increased, the solidification time tended to decrease but the compressive strength remained approximately constant. With an increase in foam production, the solidification time increased and the compressive strength decreased exponentially. The results can be used to determine the optimal material ratios of inorganic solidified foam-filled material for coal mines, and filling technology for an airtight wall was designed. A field application of the new material demonstrated that it seals crossheadings tightly, leaves no fissures, suppresses air leakage to the gob, and narrows the width of the spontaneous combustion and heat accumulation zone.

  17. A study on the microstructural characteristics of rapidly solidified Al-Fe alloys(I)

    International Nuclear Information System (INIS)

    Kim, D.H.; Lee, H.I.

    1991-01-01

    Solidification microstructures and phases in rapidly solidified Al-5, 10wt% Fe alloys have been investigated by TEM bright field and dark field imaging techniques and electron and x-ray diffraction techniques. Rapid solidification of Al-5, 10wt%Fe alloys produces various metastable and stable phases, such as Al m Fe, Al 6 Fe and Al 13 Fe 4 . In addition to these phases, clusters of randomly oriented few nm scale particles exist in the form of fine cellular network with α-Al or primary spherical particles. Solidification microstructures of the rapidly solidified Al-5, 10wt%Fe alloys consist of various combination of primary phases such as Al 13 Fe 4 , Al m Fe and cluster of nm scale particles, and cellular/dendritic structures such as fine cellular network structure of nm scale particle clusters and α-Al and cellular structure of Al m Fe and α-Al, depending upon alloy compositions and local cooling rates. (Author)

  18. The effect of grain size and cement content on index properties of weakly solidified artificial sandstones

    Science.gov (United States)

    Atapour, Hadi; Mortazavi, Ali

    2018-04-01

    The effects of textural characteristics, especially grain size, on index properties of weakly solidified artificial sandstones are studied. For this purpose, a relatively large number of laboratory tests were carried out on artificial sandstones that were produced in the laboratory. The prepared samples represent fifteen sandstone types consisting of five different median grain sizes and three different cement contents. Indices rock properties including effective porosity, bulk density, point load strength index, and Schmidt hammer values (SHVs) were determined. Experimental results showed that the grain size has significant effects on index properties of weakly solidified sandstones. The porosity of samples is inversely related to the grain size and decreases linearly as grain size increases. While a direct relationship was observed between grain size and dry bulk density, as bulk density increased with increasing median grain size. Furthermore, it was observed that the point load strength index and SHV of samples increased as a result of grain size increase. These observations are indirectly related to the porosity decrease as a function of median grain size.

  19. Microbially influenced degradation of cement-solidified low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Rogers, R.D.; Hamilton, M.A.; Veeh, R.H.; McConnell, J.W. Jr.

    1996-01-01

    Because of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. This paper contains information on three groups of microoganisms that are associated with the degradation of cement materials: sulfur-oxidizing bacteria (Thiobacillus), nitrifying bacteria (Nitrosomonas and Nitrobacter), and heterotrophic bacteria, which produce organic acids. Preliminary work using laboratory- and vendor-manufactured, simulated waste forms exposed to thiobacilli has shown that microbiologically influenced degradation has the potential to severely compromise the structural integrity of ion-exchange resin and evaporator-bottoms waste that is solidified with cement. In addition, it was found that a significant percentage of calcium was leached from the treated waste forms. Also, the surface pH of the treated specimens was decreased to below 2. These conditions apparently contributed to the physical deterioration of simulated waste forms after 30 to 60 days of exposure

  20. Leaching test of bituminized waste and waste solidified by epoxy resin

    International Nuclear Information System (INIS)

    Yoshinaka, Kazuyuki; Sugaya, Atsushi; Onizawa, Toshikazu; Takano, Yugo; Kimura, Yukihiko

    2008-10-01

    About 30,000 bituminized waste drums and about 1800 drums of waste solidified by epoxy resin, generated from Tokai Reprocessing Plant, were stored in storage facilities. And study for disposal of these waste is performed. It was considered that radioactive nuclides and chemical components were released from these waste by contact of underground water, when disposed there waste. This paper is reported that result of leaching tests for these waste, done from 2003 to 2006. We've get precious knowledge and data, as follows. (1) In leaching tests for bituminized waste, it has detected iodine-129 peak, considered difficult too low energy gamma to detect. We've get data and knowledge of iodine-129 behavior first. Leached radioactivity for 50 days calculated by peak area was equal for about 40% and 100% of including radioactivity in bituminized waste sample. And we've get data of behavior of nitric acid ion and so on, important to study for disposal, in various condition of sample shape or leaching liquid temperature. (2) In leaching test for waste solidified by epoxy resin, we've get data of behavior of TBP, radionuclides and so on, important to study for disposal. Leached TBP was equal about 1% of including of sample. And we've get data of iodine-129 behavior, too. It was confirmed that leached iodine-129 was equal for about 60% and 100% of including sample, for 90 days. (author)

  1. Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys.

    Science.gov (United States)

    Hong, Jianping; Ma, Dexin; Wang, Jun; Wang, Fu; Sun, Baode; Dong, Anping; Li, Fei; Bührig-Polaczek, Andreas

    2016-11-16

    Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS) and single crystal (SX) hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

  2. Freckle Defect Formation near the Casting Interfaces of Directionally Solidified Superalloys

    Directory of Open Access Journals (Sweden)

    Jianping Hong

    2016-11-01

    Full Text Available Freckle defects usually appear on the surface of castings and industrial ingots during the directional solidification process and most of them are located near the interface between the shell mold and superalloys. Ceramic cores create more interfaces in the directionally solidified (DS and single crystal (SX hollow turbine blades. In order to investigate the location of freckle occurrence in superalloys, superalloy CM247 LC was directionally solidified in an industrial-sized Bridgman furnace. Instead of ceramic cores, Alumina tubes were used inside of the casting specimens. It was found that freckles occur not only on the casting external surfaces, but also appear near the internal interfaces between the ceramic core and superalloys. Meanwhile, the size, initial position, and area of freckle were investigated in various diameters of the specimens. The initial position of the freckle chain reduces when the diameter of the rods increase. Freckle area follows a linear relationship in various diameters and the average freckle fraction is 1.1% of cross sectional area of casting specimens. The flow of liquid metal near the interfaces was stronger than that in the interdendritic region in the mushy zone, and explained why freckle tends to occur on the outer or inner surfaces of castings. This new phenomenon suggests that freckles are more likely to occur on the outer or inner surfaces of the hollow turbine blades.

  3. Leachability of radionuclides from cement solidified waste forms produced at operating nuclear power plants

    International Nuclear Information System (INIS)

    Croney, S.T.

    1985-03-01

    This study determined the leachability indexes of radionuclides contained in solidified liquid wastes from operating nuclear power plants. Different sizes of samples of cement-solidified liquid wastes were collected from two nuclear power plants - a pressurized water reactor and a boiling water reactor - to correlate radionuclide leaching from small- and full-sized (55-gallon) waste forms. Diffusion-based model analysis (ANS 16.1) of measured radionuclide leach data from both small- and full-sized samples was performed and indicate that leach data from small samples can be used to determine leachability indexes for full-sizes waste forms. The leachability indexes for cesium, strontium, and cobalt isotopes were determined for waste samples from both plants according to the models used for ANS 16.1. The leachability indexes for the pressurized water reactor samples were 6.4 for cesium, 7.1 for strontium, and 10.4 for cobalt. Leachability indexes for the boiling water reactor samples were 6.5 for cesium, 8.6 for strontium, and 11.1 for cobalt

  4. Surfactant-controlled synthesis of Pd/Ce{sub 0.6}Zr{sub 0.4}O{sub 2} catalyst for NO reduction by CO with excess oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.F. [Laboratorio de Catalisis y Materiales, SEPI-ESIQIE, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico); Departamento de Ingenieria Quimica, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico); Gonzalez, G. [Laboratorio de Catalisis y Materiales, SEPI-ESIQIE, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico); Wang, J.A. [Laboratorio de Catalisis y Materiales, SEPI-ESIQIE, Instituto Politecnico Nacional, Av. Politecnico S/N, Col. Zacatenco, 07738 Mexico D.F. (Mexico)]. E-mail: jwang@ipn.mx; Norena, L.E. [Departamento de Ingenieria Quimica, Universidad Autonoma Metropolitana-A, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D.F. (Mexico); Toledo, A. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Castillo, S. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico); Moran-Pineda, M. [Grupo de Molecular Ingenieria, Instituto Mexicano del Petroleo, Eje Lazaro Cardenas 152, 07730 Mexico D.F. (Mexico)

    2005-04-30

    For the first time, this work reports a surfactant-controlled synthetic method to obtain a nanophase of mesoporous ceria-zirconia solid solution containing cationic defects in the crystalline structure. The incorporation of a cationic surfactant (myristyltrimethylammonium bromide) into the ceria-zirconia solid network not only controlled the pore diameter distribution but also induced creation of the lattice defect. Ceria-zirconia solid solution showed crystal microstrain and structural distortion that varied with the calcination temperature. Compared to pure ceria, the addition of zirconium to the ceria promoted the bulk oxygen reducibility and enhanced the thermal stability of the solid. Hydrogen could be stored into or released from the PdO/Ce{sub 0.6}Zr{sub 0.4}O{sub 2} catalyst during the TPR procedure, which is associated to the formation/decomposition of a PdH{sub x} phase, due to the hydrogen dissociation catalyzed by metallic Pd. At cool start of reaction, NO reduction by CO with excess oxygen over the Pd/Ce{sub 0.6}Zr{sub 0.4}O{sub 2} catalyst showed selectivity around 100% to N{sub 2}. A competition between NO reduction by CO and CO oxidation by O{sub 2} was observed: at reaction temperatures below 200 deg. C, NO inhibited CO oxidation activity; however, at reaction temperatures above 200 deg. C, high activity of CO oxidation resulted in an inhibition effect on NO reduction.

  5. Electrochemical Stability of Li{sub 6.5}La{sub 3}Zr{sub 1.5}M{sub 0.5}O{sub 12} (M = Nb or Ta) against Metallic Lithium

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yunsung [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States); Yoo, Aeri [Department of Advanced Materials Engineering, Korea Polytechnic University, Siheung (Korea, Republic of); Schmidt, Robert; Sharafi, Asma [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States); Lee, Heechul [Department of Advanced Materials Engineering, Korea Polytechnic University, Siheung (Korea, Republic of); Wolfenstine, Jeff [Army Research Laboratory, RDRL-SED-C, Adelphi, MD (United States); Sakamoto, Jeff, E-mail: jeffsaka@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States)

    2016-05-20

    The electrochemical stability of Li{sub 6.5}La{sub 3}Zr{sub 1.5}Nb{sub 0.5}O{sub 12} (LLZNO) and Li{sub 6.5}La{sub 3}Zr{sub 1.5}Ta{sub 0.5}O{sub 12} (LLZTO) against metallic Li was studied using direct current (DC) and electrochemical impedance spectroscopy (EIS). Dense polycrystalline LLZNO (ρ = 97%) and LLZTO (ρ = 92%) were made using sol–gel synthesis and rapid induction hot-pressing at 1100°C and 15.8 MPa. During DC cycling tests at room temperature (± 0.01 mA/cm{sup 2} for 36 cycles), LLZNO exhibited an increase in Li–LLZNO interface resistance and eventually short-circuiting while the LLZTO was stable. After DC cycling, LLZNO appeared severely discolored while the LLZTO did not change in appearance. We believe the increase in Li–LLZNO interfacial resistance and discoloration are due to reduction of Nb{sup 5+} to Nb{sup 4+}. The negligible change in interfacial resistance and no color change in LLZTO suggest that Ta{sup 5+} may be more stable against reduction than Nb{sup 5+} in cubic garnet versus Li during cycling.

  6. Amorphization and evolution of magnetic properties during mechanical alloying of Co{sub 62}Nb{sub 6}Zr{sub 2}B{sub 30}: Dependence on starting boron microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, L.M.; Blázquez, J.S., E-mail: jsebas@us.es; Ipus, J.J.; Conde, A.

    2014-02-05

    Highlights: • Mechanical alloying of Co{sub 62}Nb{sub 6}Zr{sub 2}B{sub 30} leads to amorphous phase with B inclusions. • Using optimized amorphous B, amorphization occurs earlier. • B is more effectively introduced in the matrix using amorphous B. • Magnetoelasic contribution to effective magnetic anisotropy is negligible. -- Abstract: Co{sub 62}Nb{sub 6}Zr{sub 2}B{sub 30} composition was mechanically alloyed using three different types of boron powders in the starting mixture: crystalline β-B, commercial amorphous B and optimized amorphous B via ball milling. Using optimized amorphous B, amorphization process of the alloy is more efficient but milling to optimize amorphous B introduces some iron contamination. Boron inclusions (100–150 nm in size) remain even after long milling times. However, using amorphous boron reduces the fraction of boron distributed as inclusions to ∼40% of the total B. Thermal stability at the end of the milling process is affected by the initial boron microstructure. Coercivity is reduced a half using amorphous B instead of crystalline B in the starting mixture.

  7. The Effects of Cooling Rate on the Microstructure and Mechanical Properties of Ti{sub 4}0Zr{sub 1}0Cu{sub 3}6Pd{sub 1}4 Metallic Glass Matrix Composites

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seon Yong; Lim, Ka Ram; Na, Young Sang; Kim, Seong Eon [Korea Institute of Materials Science, Changwon (Korea, Republic of); Choi, Youn Suk [Pusan National University, Busan (Korea, Republic of)

    2016-11-15

    In this paper, we demonstrate that the microstructure and mechanical properties in the Ti{sub 4}0Zr{sub 1}0Cu{sub 3}6Pd{sub 1}4 alloy can be tailored by controlling the cooling rate during solidification. A lower cooling rate increases the volume fraction of crystalline phase such as B2 but decreases the free volume of the glassy matrix. The increase of the B2 volume fraction can dramatically enhance the toughness of the composites, since the B2 phase is relatively ductile compared to the glassy matrix and seems to have good interface stability with the matrix. From the experimental results, it was found that there is a transition point in the plasticity of the composites depending on the cooling rate. Here, we explain how the toughness of the composites varies in accordance with the cooling rate in the Ti{sub 4}0Zr{sub 1}0Cu{sub 3}6Pd{sub 1}4 alloy system.

  8. Improvement of the thermoplastic formability of Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass by minor addition of Erbium

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q. [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zeng, X.R., E-mail: zengxier@szu.edu.cn [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); JANUS Precision Components Co., LTD., Dongguan 523000 (China); Fu, M.W., E-mail: mmmwfu@polyu.edu.hk [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Chen, S.S. [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Jiang, J. [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China)

    2016-12-01

    The softness of Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass (BMG) in the super-cooled liquid range (SCLR) is obviously improved by minor addition of 2% Er, which makes (Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5}){sub 98}Er{sub 2} (Zr65Er2) to be a very formable Be-free Zr-based BMG. It is found the lower glass transition temperature of Zr65Er2 has an important contribution to the improvement of formability, which is contrary to the general understanding that the larger fragility and wider super-cooled liquid region (SCLR) are the major reasons for better thermoplastic formability. This finding is well explained by using the linear simplification of the SCLR in Angell plot. Zr65Er2 also has lower crystallization temperature and melting temperature, which is believed to be related to the formation of short-range ordering with lower transition energy rather than the composition shift to near eutectic. The above results help understand the effect of minor addition of rare-earth to the formability of Zr-based bulk metallic glasses.

  9. Role of nano-precipitation on the microstructure and shape memory characteristics of a new Ni{sub 50.3}Ti{sub 34.7}Zr{sub 15} shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Evirgen, A. [Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States); Karaman, I., E-mail: ikaraman@tamu.edu [Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States); Pons, J.; Santamarta, R. [Departament de Fisica, Universitat de les Illes Balears, E07122 Palma de Mallorca (Spain); Noebe, R.D. [Materials and Structures Division, NASA Glenn Research Center, Cleveland, OH 44135 (United States)

    2016-02-08

    The microstructure and shape memory characteristics of the Ni{sub 50.3}Ti{sub 34.7}Zr{sub 15} shape memory alloy were investigated as a function of aging heat treatments that result in nanometer to submicron size precipitates. Microstructure–property relationships were developed by characterizing samples using transmission electron microscopy, differential scanning calorimetry, and load-biased thermal cycling experiments. The precipitate size was found to strongly influence the martensitic transformation–precipitate interactions and ultimately the shape memory characteristics of the alloy. Aging treatments resulting in relatively fine precipitates, which are not an obstacle to twin boundaries and easily bypassed by martensite variants, exhibited higher transformation strain, lower transformation thermal hysteresis, and better thermal and dimensional stability compared to samples with relatively large precipitates. When precipitate dimensions approached several hundred nanometers in size they acted as obstacles to martensite growth, limiting martensite variant and twin size resulting in reduced functional and structural properties. Aging heat treatments were also shown to result in a wide range of transformation temperatures, increasing them above 100 °C in some cases, and affected the stress dependence of the transformation hysteresis and the stress versus transformation temperature relationships for the Ni{sub 50.3}Ti{sub 34.7}Zr{sub 15} alloy.

  10. Influence of spark plasma sintering parameters on the mechanical properties of Cu{sub 50}Zr{sub 45}Al{sub 5} bulk metallic glass obtained using metallic glass powder

    Energy Technology Data Exchange (ETDEWEB)

    Cardinal, S. [Université de Lyon, CNRS (France); INSA-Lyon, MATEIS UMR5510, F-69621 Villeurbanne (France); Pelletier, J.M., E-mail: jean-marc.pelletier@insa-lyon.fr [Université de Lyon, CNRS (France); INSA-Lyon, MATEIS UMR5510, F-69621 Villeurbanne (France); Qiao, J.C. [School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University, Xi’an 710072 (China); Bonnefont, G. [Université de Lyon, CNRS (France); INSA-Lyon, MATEIS UMR5510, F-69621 Villeurbanne (France); Xie, G. [Institute for Materials Research, Tohoku University, Sendai (Japan)

    2016-11-20

    Gas atomized Cu{sub 50}Zr{sub 45}Al{sub 5} amorphous powder was densified by spark plasma sintering, in order to obtain bulk metallic glasses with larger size than that obtained by the conventional casting strategy. The influence of different parameters was investigated: sintering temperature, isothermal holding time as well as size of the specimens. After optimization of the processing parameters, dense and amorphous specimens were elaborated with a diameter up to 30 mm. Thermal stability and mechanical properties of consolidated samples are similar to those of Cu{sub 50}Zr{sub 45} Al{sub 5} cast alloy. A hardness of 535 HV and a compressive strength of 1600 MPa have been obtained. Fractographic investigation indicated an intergranular rupture mode which leads to lower toughness compared to as the cast material, but for these samples the size is limited to 3 mm. However an increase in applied pressure (from 90 MPa to 1 GPa) induces a significant improvement in bonding between powder particles.

  11. Study of the glass forming ability of Cu{sub 60}Zr{sub 32,5}Ti{sub 7,5} alloy by molecular dynamics; Formacao de fase amorfa na liga Cu{sub 60}Zr{sub 32,5}Ti{sub 7,5} por dinamica molecular

    Energy Technology Data Exchange (ETDEWEB)

    Schimidt, C.S.; Lima, L.V.; Bastos, I.N.; Aliaga, L.C.R., E-mail: camilaschimidt17@gmail.com [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Departamento de Materiais

    2016-07-01

    This article presents the results of molecular dynamics simulation of Cu{sub 60}Zr{sub 32.5}Ti{sub 7.5} alloy through the open source code LAMMPS. Amorphous samples were produced by quenching the metallic molten from 2300K to 200K at cooling rates of 50, 5 and 0.5K/ps. The pair distribution functions of both the liquid and solid were calculated and compared at different temperatures. The topology of short-range order was analyzed using the Voronoi tessellation method, which determined the presence of Cu-centered icosahedral clusters as the prevailing in the amorphous state at 300K. Moreover, the sample was submitted to uniaxial tensile tests at strain rate of 10ps{sup -1}, in order to investigate the mechanical behavior of the metallic glass. The result of the stress-strain curve showed that applied loads lead to the plastic regime. However, the presences of shear bands, typical in the experimental testing, were not observed. Moreover, the evolution of the viscosity above the glass transition temperature and the fragility of the alloy were determined. The solidus and liquidus temperatures were determined and a good agreement with experimental data was found. (author)

  12. Evaluating the freeze-thaw durability of portland cement-stabilized-solidified heavy metal waste using acoustic measurements

    International Nuclear Information System (INIS)

    El-Korchi, T.; Gress, D.; Baldwin, K.; Bishop, P.

    1989-01-01

    The use of stress wave propagation to assess freeze-thaw resistance of portland cement solidified/stabilized waste is presented. The stress wave technique is sensitive to the internal structure of the specimens and would detect structural deterioration independent of weight loss or visual observations. The freeze-thaw resistance of a cement-solidified cadmium waste and a control was evaluated. The control and cadmium wastes both showed poor freeze-thaw resistance. However, the addition of cadmium and seawater curing increased the resistance to more cycles of freezing and thawing. This is attributed to microstructural changes

  13. Long-term leach testing of solidified radioactive waste forms (International Standard Publication ISO 6961:1982)

    International Nuclear Information System (INIS)

    Stefanik, J.

    2001-01-01

    Processes are developed for the immobilization of radionuclides by solidification of radioactive wastes. The resulting solidification products are characterized by strong resistance to leaching aimed at low release rates of the radionuclides to the environment. To measure this resistance to leaching of the solidified materials: glass, glass-ceramics, bitumen, cement, concrete, plastics, a long-term leach test is presented. The long-term leach test is aimed at: a) the comparison of different kinds or compositions of solidified waste forms; b) the intercomparison between leach test results from different laboratories on one product; c) the intercomparison between leach test results on products from different processes

  14. High throughput exploration of Zr{sub x}Si{sub 1−x}O{sub 2} dielectrics by evolutionary first-principles approaches

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jin [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, State University of New York, Stony Brook, NY 11794-2100 (United States); Zeng, Qingfeng, E-mail: qfzeng@nwpu.edu.cn [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Oganov, Artem R. [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, State University of New York, Stony Brook, NY 11794-2100 (United States); Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); Dong, Dong; Liu, Yunfang [Science and Technology on Thermostructural Composite Materials Laboratory, and International Center for Materials Discovery, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China)

    2014-11-07

    The high throughput approaches aim to discover, screen and optimize materials in a cost-effective way and to shorten their time-to-market. However, computational approaches typically involve a combinatorial explosion problem, to deal with which, we adopted hybrid evolutionary algorithms together with first-principle calculations to explore possible stable and metastable crystal structures of ZrO{sub 2}–SiO{sub 2} dielectrics. The calculation reproduced two already known structures (I4{sub 1}/amd-ZrSiO{sub 4} and I4{sub 1}/a-ZrSiO{sub 4}) and predicted two new thermodynamically metastable structures Zr{sub 3}SiO{sub 8} (P4{sup ¯}3m) and ZrSi{sub 2}O{sub 6} (P3{sup ¯}1m). At ambient pressure, the only thermodynamically stable zirconium silicate is I4{sub 1}/amd-ZrSiO{sub 4} (zircon). Dynamical stability of the new phases has been verified by phonon calculations, and their static dielectric constants are higher than that of the known phases of ZrSiO{sub 4}. Band structure, density of state, electron localization function and Bader charges are presented and discussed. The new metastable structures are insulators with the DFT band gaps of 3.65 and 3.52 eV, respectively. Calculations show that P4{sup ¯}3m-Zr{sub 3}SiO{sub 8} has high dielectric constant (∼20.7), high refractive index (∼2.4) and strong dispersion of light. Global optimization of the dielectric fitness (electric energy density) shows that among crystalline phases of ZrO{sub 2}–SiO{sub 2}, maximum occurs for I4{sub 1}/a-ZrSiO{sub 4}. - Highlights: • Two new thermodynamically metastable ZrO{sub 2}–SiO{sub 2} compounds are predicted. • The predicated P-43m or P4{sup ¯}3m-Zr{sub 3}SiO{sub 8} has the highest dielectric constant and refractive index. • I4{sub 1}/a-ZrSiO{sub 4} shows the highest electric energy density among ZrO{sub 2}–SiO{sub 2} dielectrics.

  15. Evaluation of leaching behavior and immobilization of zinc in cement-based solidified products

    Directory of Open Access Journals (Sweden)

    Krolo Petar

    2012-01-01

    Full Text Available This study has examined leaching behavior of monolithic stabilized/solidified products contaminated with zinc by performing modified dynamic leaching test. The effectiveness of cement-based stabilization/solidification treatment was evaluated by determining the cumulative release of Zn and diffusion coefficients, De. The experimental results indicated that the cumulative release of Zn decreases as the addition of binder increases. The values of the Zn diffusion coefficients for all samples ranged from 1.210-8 to 1.1610-12 cm2 s-1. The samples with higher amounts of binder had lower De values. The test results showed that cement-based stabilization/solidification treatment was effective in immobilization of electroplating sludge and waste zeolite. A model developed by de Groot and van der Sloot was used to clarify the controlling mechanisms. The controlling leaching mechanism was found to be diffusion for samples with small amounts of waste material, and dissolution for higher waste contents.

  16. Processing method of radiation concrete waste and manufacturing method for radioactive waste solidifying filling mortar

    International Nuclear Information System (INIS)

    Sukekiyo, Mitsuaki; Okamoto, Masamichi

    1998-01-01

    Radioactive concrete wastes are crushed and pulverized. Fine solid granular materials caused by the pulverization are classified and the grain size is controlled so that the maximum grain size is 2.5mm, with the grains having a grain size of up to 0.15mm being up to 30% by weight to form fine aggregates. Separated and recovered fine concrete powders are classified and the size of the powder is controlled within a range of from 3,000 to 15,000cm 2 /g which is smaller than cement particles to form fine powders having a stable quality suitable as a mixing agent. The fine aggregates and the mixing agent are mixed to form a filling mortar (filler) for solidifying radioactive wastes. The filling mortar is filled together with other radioactive wastes in a drum to form a waste body in a drum. With such a constitution, crushed radioactive concrete wastes can be reutilized completely. (I.N.)

  17. Retrievable surface storage: interim storage of solidified high-level waste

    International Nuclear Information System (INIS)

    LaRiviere, J.R.; Nelson, D.C.

    1976-01-01

    Studies have been conducted on retrievable-surface-storage concepts for the interim storage of solidified high-level wastes. These studies have been reviewed by the Panel on Engineered Storage, convened by the Committee on Radioactive Waste Management of the National Research Council-National Academy of Sciences. The Panel has concluded that ''retrievable surface storage is an acceptable interim stage in a comprehensive system for managing high-level radioactive wastes.'' The scaled storage cask concept, which was recommended by the Panel on Engineered Storage, consists of placing a canister of waste inside a carbon-steel cask, which in turn is placed inside a thick concrete cylinder. The waste is cooled by natural convection air flow through an annulus between the cask and the inner wall of the concrete cylinder. The complete assembly is placed above ground in an outdoor storage area

  18. Solidified structure of thin-walled titanium parts by vertical centrifugal casting

    Directory of Open Access Journals (Sweden)

    Wu Shiping

    2011-05-01

    Full Text Available The solidified structure of the thin-walled and complicated Ti-6Al-4V castings produced by the vertical centrifugal casting process was studied in the present work. The results show that the wall thickness of the section is featured with homogeneously distributed fine equiaxial grains, compared with the microstructure of the thick-walled section. The grain size of the castings has a tendency to decrease gradually with the increasing of the centrifugal radius. The inter-lamellar space in thick-walled casting parts is bigger than that of the thin-walled parts, and the profile of inter-lamellar space is not susceptible to the centrifugal radius.

  19. On oscillatory microstructure during cellular growth of directionally solidified Sn-36at.%Ni peritectic alloy.

    Science.gov (United States)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie

    2016-04-12

    An oscillatory microstructure has been observed during deep-cellular growth of directionally solidified Sn-36at.%Ni hyperperitectic alloy containing intermetallic compounds with narrow solubility range. This oscillatory microstructure with a dimension of tens of micrometers has been observed for the first time. The morphology of this wave-like oscillatory structure is similar to secondary dendrite arms, and can be observed only in some local positions of the sample. Through analysis such as successive sectioning of the sample, it can be concluded that this oscillatory microstructure is caused by oscillatory convection of the mushy zone during solidification. And the influence of convection on this oscillatory microstructure was characterized through comparison between experimental and calculations results on the wavelength. Besides, the change in morphology of this oscillatory microstructure has been proved to be caused by peritectic transformation during solidification. Furthermore, the melt concentration increases continuously during solidification of intermetallic compounds with narrow solubility range, which helps formation of this oscillatory microstructure.

  20. Annual report on the development and characterization of solidified forms for nuclear wastes, 1979

    International Nuclear Information System (INIS)

    Chick, L.A.; McVay, G.L.; Mellinger, G.B.; Roberts, F.P.

    1980-12-01

    Development and characterization of solidified nuclear waste forms is a major continuing effort at Pacific Northwest Laboratory. Contributions from seven programs directed at understanding chemical composition, process conditions, and long-term behaviors of various nuclear waste forms are included in this report. The major findings of the report are included in extended figure captions that can be read as brief technical summaries of the research, with additional information included in a traditional narrative format. Waste form development proceeded on crystalline and glass materials for high-level and transuranic (TRU) wastes. Leaching studies emphasized new areas of research aimed at more basic understanding of waste form/aqueous solution interactions. Phase behavior and thermal effects research included studies on crystal phases in defense and TRU waste glasses and on liquid-liquid phase separation in borosilicate waste glasses. Radiation damage effects in crystals and glasses from alpha decay and from transmutation are reported

  1. Experimental study of directionally solidified ferromagnetic shape memory alloy under multi-field coupling

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yuping, E-mail: zhuyuping@126.com [Institute of Geophysics, China Earthquake Administration, Beijing 100081 (China); Chen, Tao; Teng, Yao [Faculty of Civil Engineering and Mechanics, Jiangsu University, Zhenjiang 212013 (China); Liu, Bingfei [Airport College, Civil Aviation University of China, Tianjin 300300 (China); Xue, Lijun [Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, School of Mechanical Engineering, Tianjin University of Technology, Tianjin 300384 (China)

    2016-11-01

    Directionally solidified, polycrystalline Ni–Mn–Ga is studied in this paper. The polycrystalline Ni–Mn–Ga samples were cut at different angles to solidification direction. The magnetic field induced strain under constant stress and the temperature-induced strain under constant magnetic field during the loading–unloading cycle were measured. The experimental results show that the mechanical behavior during the loading–unloading cycle of the material is nonlinear and anisotropic. Based on the experimental results, the effects of multi-field coupling factors, such as stress, magnetic field, temperature and cutting angle on the mechanical behaviors were analyzed. Some useful conclusions were obtained, which will provide guidance for practical applications. - Highlights: • The magnetic-induced strains in different directions are tested. • The temperature-induced strains in different directions are tested. • The effects of coupling factors on directional solidification samples are studied.

  2. The Characterization of Filtration Waste Solidified Product from Baghouse Filter of the Incineration Process

    International Nuclear Information System (INIS)

    Sutoto

    2000-01-01

    To increase of the safety, quality and to easy maintenance of the incinerator media of bag house filter, coating of the surface filter media by CaCO 3 powder were done. In the incinerator process, the CaCO 3 powder will scrub of fly ash as secondary waste. And finally, both of the secondary waste and CaCO 3 will immobilized by cement matrix. The research has an objective to study and characterizing of the CaCO 3 as secondary waste on their cemented product. The research were done on block samples with content of CaCO 3 and the properties characterized by compressive strength and density. From this research known that on their solidified, each quantity of CaCO 3 will be impact to decreasing of the quality cementation product. The optimum formula for solidification of bag house filter scrubbed is CaCO 3 : cement: water is 3 : 10 : 7. (author)

  3. Relationship between critical current properties and microstructure in cylindrical RE123 melt-solidified bulks

    International Nuclear Information System (INIS)

    Nakashima, T.; Shimoyama, J.; Honzumi, M.; Tazaki, Y.; Horii, S.; Kishio, K.

    2005-01-01

    We report the synthesis of cylindrical melt-solidified bulks in REBa 2 Cu 3 O y (RE = Sm, Gd, Dy, Ho, Y and Er), and their critical current properties and microstructures of the a- and the c-growth regions. It was found from the microstructure analysis that the volume fractions of RE211 particles in the c-growth region were always lower than those in the a-growth region. Moreover, those in the c-growth region were increased with distance from the seed crystal. Interestingly, the second peak effects in J c -B curves were prominently enhanced for the c-growth region. J c values at zero field for the c-growth region through the appropriate oxygen post-annealing reached approximately 95 kA cm -2 for RE = Ho, Dy and Y

  4. Structure and mechanical properties of Al-3Fe rapidly solidified alloy

    International Nuclear Information System (INIS)

    Karakoese, Ercan; Keskin, Mustafa

    2011-01-01

    The Al based Al-3 wt%Fe alloy was prepared by conventionally casting (ingot) and further processed the melt-spinning technique and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC) and the Vickers microhardness tester. The rapidly solidified (RS) binary alloys were composed of supersaturated α-Al solid solution and finely dispersed intermetallic phases. Experimental results showed that the mechanical properties of RS alloys were enhanced, which can be attributed to significant changes in the microstructure. The dependence of microhardness H V on the solidification rate (V) was analysed. These results showed that with the increasing values of V, the values of H V increased.

  5. Phase composition of rapidly solidified Ag-Sn-Cu dental alloys

    International Nuclear Information System (INIS)

    Lecong Dzuong; Do Minh Nghiep; Nguyen van Dzan; Cao the Ha

    1996-01-01

    The phase composition of some rapidly solidified Ag-Sn-Cu dental alloys with different copper contents (6.22 wtpct) has been studied by XRD, EMPA and optical microscopy. The samples were prepared from melt-spun ribbons. The microstructure of the as-quenched ribbons was microcrystalline and consisted of the Ag sub 3 Sn, Ag sub 4 Sn, Cu sub 3 Sn and Cu sub 3 Sn sub 8 phases. Mixing with mercury (amalgamation) led to formation of the Ag sub 2 Hg sub 3, Sn sub 7 Hg and Cu sub 6 Sn sub 5 phases. The amount of copper atoms in the alloys played an important role in phase formation in the amalgams

  6. Solute redistribution and Rayleigh number in the mushy zone during directional solidifi cation of Inconel 718

    Directory of Open Access Journals (Sweden)

    Wang Ling

    2009-08-01

    Full Text Available The interdendritic segregation along the mushy zone of directionally solidifi ed superalloy Inconel 718 has been measured by scanning electron microscope (SEM and energy dispersion analysis spectrometry (EDAXtechniques and the corresponding liquid composition profile was presented. The liquid density and Rayleigh number (Ra profi les along the mushy zone were calculated as well. It was found that the liquid density difference increased from top to bottom in the mushy zone and there was no density inversion due to the segregation of Nb and Mo. However carbide formation in the freezing range and the preferred angle of the orientated dendrite array could prompt the fl uid fl ow in the mushy zone although there was no liquid density inversion. The largest relative Rayleigh number appeared at 1,326 篊 for Inconel 718 where the fl uid fl ow most easily occurred.

  7. Microstructure and property of directionally solidified Ni-Si hypereutectic alloy

    Science.gov (United States)

    Cui, Chunjuan; Tian, Lulu; Zhang, Jun; Yu, Shengnan; Liu, Lin; Fu, Hengzhi

    2016-03-01

    This paper investigates the influence of the solidification rate on the microstructure, solid/liquid interface, and micro-hardness of the directionally solidified Ni-Si hypereutectic alloy. Microstructure of the Ni-Si hypereutectic alloy is refined with the increase of the solidification rate. The Ni-Si hypereutectic composite is mainly composed of α-Ni matrix, Ni-Ni3Si eutectic phase, and metastable Ni31Si12 phase. The solid/liquid interface always keeps planar interface no matter how high the solidification rate is increased. This is proved by the calculation in terms of M-S interface stability criterion. Moreover, the Ni-Si hypereutectic composites present higher micro-hardness as compared with that of the pure Ni3Si compound. This is caused by the formation of the metastable Ni31Si12 phase and NiSi phase during the directional solidification process.

  8. Importance of microscopy in durability studies of solidified and stabilized contaminated soils

    Science.gov (United States)

    Klich, I.; Wilding, L.P.; Drees, L.R.; Landa, E.R.

    1999-01-01

    Solidification/stabilization (S/S) is recognized by the U.S. EPA as a best demonstrated available technology for the containment of contaminated soils and other hazardous wastes that cannot be destroyed by chemical, thermal, or biological means. Despite the increased use of S/S technologies, little research has been conducted on the weathering and degradation of solidified and stabilized wastes once the treated materials have been buried. Published data to verify the performance and durability of landfilled treated wastes over time are rare. In this preliminary study, optical and electron microscopy (scanning electron microscopy [SEM], transmission electron microscopy [TEM] and electron probe microanalyses [EPMA]) were used to evaluate weathering features associated with metal-bearing contaminated soil that had been solidified and stabilized with Portland cement and subsequently buried on site, stored outdoors aboveground, or achieved in a laboratory warehouse for up to 6 yr. Physical and chemical alteration processes identified include: freeze-thaw cracking, cracking caused by the formation of expansive minerals such as ettringite, carbonation, and the movement of metals from waste aggregates into the cement micromass. Although the extent of degradation after 6 yr is considered slight to moderate, results of this study show that the same environmental concerns that affect the durability of concrete must be considered when evaluating the durability and permanence of the solidification and stabilization of contaminated soils with cement. In addition, such evaluations cannot be based on leaching and chemical analyses alone. The use of all levels of microscopic analyses must be incorporated into studies of the long-term performance of S/S technologies.Solidification/stabilization (S/S) is recognized by the U.S. EPA as a best demonstrated available technology for the containment of contaminated soils and other hazardous wastes that cannot be destroyed by chemical

  9. 3D observation of the solidified structures by x-ray micro computerized tomography

    International Nuclear Information System (INIS)

    Yasuda, Hideyuki; Ohnaka, Itsuo; Tsuchiyama, Akira; Nakano, Tsukasa; Uesugi, Kentaro

    2003-01-01

    The high flux density of the monochromatized and well-collimated X-ray and the high-resolution detector provide a new 3D observation tool for microstructures of metallic alloys and ceramics. The X-ray micro computerized tomography in BL47XU of SPring-8 (SP-μCT) was applied to observe microstructures produced through the eutectic reaction for Sn-based alloys and an Al 2 O 3 -Y 2 O 3 oxide system. The constituent phases in the eutectic structures were three-dimensionally identified, in which the lamellar spacing ranged from several to 10 μm. Since the 3D structure of the unidirectionally solidified specimens contains history of the eutectic structure formation, the 3D structure obtained by SP-μCT gives useful information to consider the microstructure evolution. (author)

  10. Radial macrosegregation and dendrite clustering in directionally solidified Al-7Si and Al-19Cu alloys

    Science.gov (United States)

    Ghods, M.; Johnson, L.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2016-05-01

    Hypoeutectic Al-7 wt% Si and Al-19 wt% Cu alloys were directionally solidified upward in a Bridgman furnace through a range of constant growth speeds and thermal gradients. Though processing is thermo-solutally stable, flow initiated by gravity-independent advection at, slightly leading, central dendrites moves rejected solute out ahead and across the advancing interface. Here any lagging dendrites are further suppressed which promotes a curved solid-liquid interface and the eventual dendrite "clustering" seen in transverse sections (dendrite "steepling" in longitudinal orientations) as well as extensive radial macrosegregation. Both aluminum alloys showed considerable macrosegregation at the low growth speeds (10 and 30 μm s-1) but not at higher speed (72 μm s-1). Distribution of the fraction eutectic-constituent on transverse sections was determined in order to quantitatively describe radial macrosegregation. The convective mechanisms leading to dendrite-steepling were elucidated with numerical simulations, and their results compared with the experimental observations.

  11. Microstructure of rapidly solidified Al2O3-dispersion-strengthened Type 316 stainless steel

    International Nuclear Information System (INIS)

    Megusar, J.; Arnberg, L.; Vander Sande, J.B.; Grant, N.J.

    1981-01-01

    An aluminum oxide dispersion strengthened 316 stainless steel was developed by surface oxidation. Surface oxidation was chosen as a preferred method in order to minimize formation of less stable chromium oxides. Ultra low C+N 316 stainless steel was alloyed with 1 wt % Al, rapidly solidified to produce fine powders and attrited to approximately 0.5 μm thick flakes to provide for surface oxidation. Oxide particles in the extruded material were identified mostly as Al oxides. In the preirradiated condition, oxide dispersion retarded crystallization and grain growth and had an effect on room temperature tensile properties. These structural modifications are expected to have an effect on the swelling resistance, structure stability and high temperature strength of austenitic stainless steels

  12. Experimental study on the leaching of radioactive materials from radioactive wastes solidified in cement into sea water. Part 2

    International Nuclear Information System (INIS)

    Hatta, H.; Ono, H.; Nagakura, T.; Machida, T.; Seki, T.; Maki, Y.

    Results are presented from the study on leachability of 60 Co and 137 Cs from BWR concentrated wastes that had been solidified in cement. The leachability of 60 Co is very small compared to that of 137 Cs and varies greatly with the type of leaching medium. The effect of duration of immersion on leachability is comparatively large

  13. A Laboratory Screening Study On The Use Of Solidifiers As A Response Tool To Remove Crude Oil Slicks On Seawater

    Science.gov (United States)

    The effectiveness of five solidifiers to remove Prudhoe Bay crude oil from artificial seawater in the laboratory was determined by ultraviolet-visible spectroscopy (UV-VIS) and gas chromatography/mass spectrometry (GC/MS). The performance of the solidifers was determined by US-V...

  14. Formation of metastable phases and nanocomposite structures in rapidly solidified Al-Fe alloys

    International Nuclear Information System (INIS)

    Nayak, S.S.; Chang, H.J.; Kim, D.H.; Pabi, S.K.; Murty, B.S.

    2011-01-01

    Highlights: → Structures of nanocomposites in rapidly solidified Al-Fe alloys were investigated. → Nanoquasicrystalline, amorphous and intermetallics phases coexist with α-Al. → Nanoquasicrystalline phase was observed for the first time in the dilute Al alloys. → Thermodynamic driving force plays dominant role in precipitation of Fe-rich phases. → High hardness (3.57 GPa) was observed for nanocomposite of Al-10Fe alloy. - Abstract: In the present work the structure and morphology of the phases of nanocomposites formed in rapidly solidified Al-Fe alloys were investigated in details using analytical transmission electron microscopy and X-ray diffraction. Nanoquasicrystalline phases, amorphous phase and intermetallics like Al 5 Fe 2 , Al 13 F 4 coexisted with α-Al in nanocomposites of the melt spun alloys. It was seen that the Fe supersaturation in α-Al diminished with the increase in Fe content and wheel speed indicating the dominant role of the thermodynamic driving force in the precipitation of Fe-rich phases. Nanoquasicrystalline phases were observed for the first time in the dilute Al alloys like Al-2.5Fe and Al-5Fe as confirmed by high resolution TEM. High hardness (3.57 GPa) was measured in nanocomposite of Al-10Fe alloy, which was attributed to synergistic effect of solid solution strengthening due to high solute content (9.17 at.% Fe), dispersion strengthening by high volume fraction of nanoquasicrystalline phase; and Hall-Petch strengthening from finer cell size (20-30 nm) of α-Al matrix.

  15. Surface free energy of polypropylene and polycarbonate solidifying at different solid surfaces

    International Nuclear Information System (INIS)

    Chibowski, Emil; Terpilowski, Konrad

    2009-01-01

    Advancing and receding contact angles of water, formamide, glycerol and diiodomethane were measured on polypropylene (PP) and polycarbonate (PC) sample surfaces which solidified at Teflon, glass or stainless steel as matrix surfaces. Then from the contact angle hystereses (CAH) the apparent free energies γ s tot of the surfaces were evaluated. The original PP surface is practically nonpolar, possessing small electron donor interaction (γ s - =1.91mJ/m 2 ), as determined from the advancing contact angles of these liquids. It may result from impurities of the polymerization process. However, it increases up to 8-10 mJ/m 2 for PP surfaces contacted with the solids. The PC surfaces both original and modified show practically the same γ s - =6.56.7mJ/m 2 . No electron acceptor interaction is found on the surfaces. The γ s tot of modified PP and PC surfaces depend on the kind of probe liquid and contacted solid surface. The modified PP γ s tot values determined from CAH of polar liquids are greater than that of original surface and they increase in the sequence: Teflon, glass, stainless steel surface, at which they solidified. No clear dependence is observed between γ s tot and dielectric constant or dipole moment of the polar probe liquids. The changes in γ s tot of the polymer surfaces are due to the polymer nature and changes in its surface structure caused by the structure and force field of the contacting solid. It has been confirmed by AFM images.

  16. Leachability and heavy metal speciation of 17-year old stabilised/solidified contaminated site soils

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fei, E-mail: fwtiffany@gmail.com [Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Wang, Hailing, E-mail: wanghailing@njtech.edu.cn [College of Environment, Nanjing Tech University, Nanjing 210009 (China); Al-Tabbaa, Abir, E-mail: aa22@cam.ac.uk [Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2014-08-15

    Highlights: • The effectiveness of the cement-based S/S at 17 years in West Drayton site is still satisfactory. • Major leaching of Cu, Zn, Ni, Cd and Pb in all mixes took place in the Fe/Mn oxides phase. • The hydration process has been fully completed and further carbonation took place at 17 years. • Microstructure analyses show that unreacted PFA exists. - Abstract: The long-term leachability, heavy metal speciation transformation and binding mechanisms in a field stabilised/solidified contaminated soil (made ground) from West Drayton site were recently investigated following in situ auger mixing treatment with a number of cement-based binders back in 1996. Two batch leaching tests (TCLP and BS EN 12457) and a modified five step sequential extraction procedure along with X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were employed for the testing of the 17-year-old field soil. The results of batch leaching tests show that the treatment employed remained effective at 17 years of service time, with all BS EN 12457 test samples and most of TCLP test samples satisfied drinking water standards. Sequential extraction results illustrate that the leaching of Cu, Ni, Zn, Pb and Cd in all mixes mainly occurred at the Fe/Mn phase, ranging from 43% to 83%. Amongst the five metals tested, Ni was the most stable with around 40% remained in the residual phase for all the different cement-based binder stabilised/solidified samples. XRD and SEM analyses show that the hydration process has been fully completed and further carbonation took place. In summary, this study confirms that such cement-based stabilisation/solidification (S/S) treatment can achieve satisfactory durability and thus is a reliable technique for long-term remediation of heavy metal contaminated soil.

  17. Study on Magnesium in Rainwater and Fertilizer Infiltration to Solidified Peat

    Science.gov (United States)

    Tajuddin, S. A. M.; Rahman, J. A.; Mohamed, R. M. S. R.

    2018-04-01

    Magnesium is a component of several primary and secondary minerals in the soil which are essentially insoluble for agricultural purpose. The presence of water infiltrate in the soil allows magnesium to dissolve together into the groundwater. In fertilizers, magnesium is categorized as secondary macronutrient which supplies food and encouraging for plants growth. The main objective of this study was to determine the concentration of magnesium in fibric peat when applied the solidification under different conditions. Physical model was used as a mechanism for the analysis of the experimental data using a soil column as an equipment to produce water leaching. In this investigation, there were four outlets in the soil column which were prepared from the top of the column to the bottom with the purpose of identifying the concentration of magnesium for each soil level. The water leaching of each outlet was tested using atomic absorption spectroscopy (AAS). The results obtained showed that the highest concentrations of magnesium for flush and control condition at outlet 4 was 12.50 ppm and 1.29 ppm respectively. Similarly, fibric with solidified peat under rainwater recorded the highest value of 3.16 at outlet 1 for wet condition while for dry condition at outlet 4 of 1.33 ppm. However, the difference in fibric with solidified peat under rainwater and fertilizer condition showed that the highest value for the wet condition was achieved at outlet 1 with 5.43 ppm while highest value of 1.26 ppm was obtained for the dry condition at the outlet 4. It was concluded that the outlets in the soil column gave a detailed analysis of the concentration of magnesium in the soil which was influenced by the environmental conditions.

  18. The responses of endothelial cells to Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} metallic glass in vitro and in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing, E-mail: monkeys0109@sina.com; Ai, Hong-jun

    2014-07-01

    The goal of this study was to evaluate the biocompatibility of newly developed Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} metallic glass (denoted ZT1) and its parallel material, commercially pure titanium (CP-Ti), as dental implants. To this end, we evaluated their cytotoxicity in vitro using human umbilical vein endothelial cells (HUVECs) and in vivo by performing an oral mucosa irritation test in hamsters. Specifically, cytotoxicity was determined in HUVECs by evaluating their cell morphology using scanning electron microscopy (SEM) and their cell viability using CCK-8 assays. Moreover, we examined the mRNA levels of vascular endothelial growth factor and von Willebrand factor by quantitative PCR (qPCR). In the early stages of proliferation and differentiation, no differences were observed between HUVECs inoculated on ZT1 compared to those on CP-Ti. However, in the later stages of proliferation and differentiation, the HUVECs inoculated on ZT1 were significantly better than the cells cultured on CP-Ti. In the oral mucosa irritation test, we sutured sample discs into the cheek pouch of hamsters. After 2, 3, and 4 weeks, we harvested the corresponding mucosal tissues, stained them with hematoxylin and eosin, obtained blood samples for biochemical analysis, and finally, observed the topography of the sample discs by SEM. Immunohistochemistry and hematology analyses showed no differences in the biocompatibility of ZT1 and CP-Ti, and neither of these compounds caused irritation of the mucosa. In addition, SEM images showed that no pitting occurred on the sample discs. Together, these data indicate that ZT1 may be a good candidate for dental implants and should be further studied. - Graphical abstract: The results of blood analysis. (a) WBC, (b) Mon %, (c) Neu %, and (d) Eos %. - Highlights: • We used HUVECs to evaluate the cytotoxicity of Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} BMG. • We are the first to evaluate Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} BMG using an

  19. Surface defects on the Gd{sub 2}Zr{sub 2}O{sub 7} oxide films grown on textured NiW technical substrates by chemical solution method

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y., E-mail: yuezhao@sjtu.edu.cn [School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 200240 Shanghai (China); Department of Energy Conversion and Storage, Technical University of Denmark, 4000 Roskilde (Denmark); Opata, Yuri A. [Department of Energy Conversion and Storage, Technical University of Denmark, 4000 Roskilde (Denmark); Wu, W. [School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 200240 Shanghai (China); Grivel, J.C. [Department of Energy Conversion and Storage, Technical University of Denmark, 4000 Roskilde (Denmark)

    2017-02-15

    Epitaxial growth of oxide thin films has attracted much interest because of their broad applications in various fields. In this study, we investigated the microstructure of textured Gd{sub 2}Zr{sub 2}O{sub 7} films grown on (001)〈100〉 orientated NiW alloy substrates by a chemical solution deposition (CSD) method. The aging effect of precursor solution on defect formation was thoroughly investigated. A slight difference was observed between the as-obtained and aged precursor solutions with respect to the phase purity and global texture of films prepared using these solutions. However, the surface morphologies are different, i.e., some regular-shaped regions (mainly hexagonal or dodecagonal) were observed on the film prepared using the as-obtained precursor, whereas the film prepared using the aged precursor exhibits a homogeneous structure. Electron backscatter diffraction and scanning electron microscopy analyses showed that the Gd{sub 2}Zr{sub 2}O{sub 7} grains present within the regular-shaped regions are polycrystalline, whereas those present in the surrounding are epitaxial. Some polycrystalline regions ranging from several micrometers to several tens of micrometers grew across the NiW grain boundaries underneath. To understand this phenomenon, the properties of the precursors and corresponding xerogel were studied by Fourier transform infrared spectroscopy and coupled thermogravimetry/differential thermal analysis. The results showed that both the solutions mainly contain small Gd−Zr−O clusters obtained by the reaction of zirconium acetylacetonate with propionic acid during the precursor synthesis. The regular-shaped regions were probably formed by large Gd−Zr−O frameworks with a metastable structure in the solution with limited aging time. This study demonstrates the importance of the precise control of chemical reaction path to enhance the stability and homogeneity of the precursors of the CSD route. - Highlights: •We investigate microstructure

  20. Theoretical studies of the local structures and EPR parameters for the rhombic Cu{sup 2+} center in Cu{sub 0.5}Zr{sub 2}(PO{sub 4}){sub 3} phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao-Ying [Shangrao Normal College, Jiangxi (China). College of Physics and Electronic Information; Huang, Ying; Tu, Qiu [Shangrao Normal College, Jiangxi (China). School of Physics and Electronic Information

    2015-07-01

    The local structure of the rhombic Cu{sup 2+} center in Cu{sub 0.5}Zr{sub 2}(PO{sub 4}){sub 3} phosphate is investigated by using the high-order perturbation formulas of electron paramagnetic resonance (EPR) parameters, g-factors g{sub i} (i = x, y, z), and hyperfine structure constants A{sub i} for 3d{sup 9} ions in rhombically elongated octahedral symmetry. According to the studies, the local axial distortion angle Δα (∼ 5.1 ) and the planar bond angle θ (∼ 83.8 ) in [CuO{sub 6}]{sup 10-} cluster was obtained. The theoretical EPR parameters based on the aforementioned local structure parameters show good agreement with the observed values, and some improvement have been made as compared with the previous studies.

  1. Calculations of the magnetic entropy change in amorphous through a microscopic anisotropic model: Applications to Dy{sub 70}Zr{sub 30} and DyCo{sub 3.4} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P. J. von, E-mail: von.ranke@uol.com.br; Nóbrega, E. P.; Ribeiro, P. O.; Alvarenga, T. S. T.; Lopes, P. H. O.; Sousa, V. S. R. de; Oliveira, N. A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro (Brazil); Alho, B. P. [Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 Rio de Janeiro (Brazil); Carvalho, G. [Laboratório Nacional de Luz Sincroton—LNLS, 13083-970 Campinas, São Paulo (Brazil); Magnus, A.

    2014-10-14

    We report theoretical investigations on the magnetocaloric effect, described by the magnetic entropy change in rare earth—transition metal amorphous systems. The model includes the local anisotropy on the rare earth ions in Harris-Plischke-Zuckermann assumptions. The transition metals ions are treated in terms of itinerant electron ferromagnetism and the magnetic moment of rare earth ions is coupled to the polarized d-band by a local exchange interaction. The magnetocaloric effect was calculated in DyCo{sub 3.4} system, which presents amorphous sperimagnetic configuration. The calculations predict higher refrigerant capacity in the amorphous DyCo{sub 3.4} than in DyCo{sub 2} crystal, highlighting the importance of amorphous magnetocaloric materials. Our calculation of the magnetocaloric effect in Dy{sub 70}Zr{sub 30}, which presents amorphous asperomagnetic configuration, is in good agreement with the experimental result. Furthermore, magnetic entropy changes associated with crystal-amorphous configurations change are estimated.

  2. Superconductivity of Ta{sub 34}Nb{sub 33}Hf{sub 8}Zr{sub 14}Ti{sub 11} high entropy alloy from first principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Jasiewicz, K.; Wiendlocha, B.; Korben, P.; Kaprzyk, S.; Tobola, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Al. Mickiewicza 30, 30-059, Krakow (Poland)

    2016-05-15

    The Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) is applied to study the first superconducting high entropy alloy (HEA) Ta{sub 34}Nb{sub 33}Hf{sub 8}Zr{sub 14}Ti{sub 11} (discovered in 2014 with T{sub c}=7.3 K), focusing on estimations of the electron-phonon coupling constant λ. The electronic part of λ has been calculated using the rigid muffin-tin approximation (RMTA), while the phonon part has been approximated using average atomic mass and experimental Debye temperature. The estimated λ=1.16 is close to the value determined from specific heat measurements, λ=0.98, and suggests rather strong electron-phonon coupling in this material. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Formation and growth of crystal defects in directionally solidified multicrystalline silicon for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ryningen, Birgit

    2008-07-01

    Included in this thesis are five publications and one report. The common theme is characterisation of directionally solidified multicrystalline silicon for solar cells. Material characterisation of solar cell silicon is naturally closely linked to both the casting process and to the solar cell processing: Many of the material properties are determined by the casting process, and the solar cell processing will to some extend determine which properties will influence the solar cell performance. Solar grade silicon (SoG-Si) made by metallurgical refining route and supplied by Elkem Solar was directionally solidified and subsequently characterised, and a simple solar cell process was applied. Except from some metallic co-precipitates in the top of the ingot, no abnormalities were found, and it is suggested that within the limits of the tests performed in this thesis, the casting and the solar cell processing, rather than the assumed higher impurity content, was the limiting factor. It is suggested in this thesis that the main quality problem in multicrystalline silicon wafers is the existence of dislocation clusters covering large wafer areas. The clusters will reduce the effect of gettering and even if gettering could be performed successfully, the clusters will still reduce the minority carrier mobility and hence the solar cell performance. It has further been pointed out that ingots solidified under seemingly equal conditions might have a pronounced difference in minority carrier lifetime. Ingots with low minority carrier lifetime have high dislocation densities. The ingots with the substantially higher lifetime seem all to be dominated by twins. It is also found a link between a higher undercooling and the ingots dominated by twins. It is suggested that the two types of ingots are subject to different nucleation and crystal growth mechanisms: For the ingots dominated by dislocations, which are over represented, the crystal growth is randomly nucleated at the

  4. Interplay between temperature gradients field and C - E transformation in solidifying rolls

    Directory of Open Access Journals (Sweden)

    W. Wołczyński

    2009-07-01

    Full Text Available At first step of simulation a temperature field for solidifying cast steel and cast iron roll has been performed. The calculation does not take into account the convection in the liquid since convection has no influence on the proposed model for the localization of the C-E (columnar to equiaxed grains transformation. However, it allows to study the dynamics of temperature field temporal behavior in the middle of a mould. It is postulated that for the C-E transition a full accumulation of the heat in the mould has been observed (plateau at the T(t curve. The temporal range of plateau existence corresponds to the incubation time for the full equiaxed grains formation. At the second step of simulation temporal behavior of the temperature gradient field has been studied. Three ranges within temperature gradients field have been distinguished for the operating point situated at the middle of mould: a/ for the formation of columnar grains zone, ( and high temperature gradient 0>>T&0//>>∂∂−∂∂∂∂−∂∂>EttEtrTrT. T - temperature, r - roll radius. It is evident that the heat transfer across the mould decides on the temporal appearance of incubation during which the solidification is significantly arrested and competition between columnar and equiaxed growth occurs. Moreover solidification with positive temperature gradient transforms into solidification with negative temperature gradient (locally after the incubation. A simulation has been performed for the cast steel and cast iron rolls solidifying as in industry condition. Since the incubation divides the roll into to parts (first with columnar structure, second with equiaxed structure some experiments dealing with solidification have been made in laboratory scale. Finally, observations of the macrosegregation or microsegregation and phase or structure appearance in the cast iron ingot / roll (made in laboratory has also been done in order to confront them with theoretical predictions

  5. Properties of rapidly solidified Fe-Cr-Al ribbons for the use as automotive exhaust gas catalyst substrates

    International Nuclear Information System (INIS)

    Emmerich, K.

    1993-01-01

    Metallic honeycomb structures are used as catalyst substrates in automotive exhaust gas systems. This application requires an outstanding corrosion resistance at elevated temperatures of the substrate material. Technical improvements can be achieved by the use of rapid solidification technology for the production of the Fe-Cr-Al ribbons since the Al content can be substantially increased from about 5% Al in the conventionally rolled material to about 12% Al in the rapid solidified ribbon. As a result the lifetime of the ribbon in a higher-temperature corrosion environment is drastically increased. In addition the scale/metal adherance is improved. The impediment of recrystallization in the rapidly solidified ribbons prevents an embrittlement even in carbonizing atmospheres. (orig.)

  6. Evaluation of the performance of solidified commercial low-level wastes in an arid climate

    International Nuclear Information System (INIS)

    Graham, M.J.; Walter, M.B.

    1984-01-01

    Shallow land burial is being used as a disposal method for commercial low-level waste at waste disposal sites in arid (Hanford, Washington) and humid (Barnwell, South Carolina) climatic regions. A field lysimeter facility has been established at Hanford in which to conduct waste-form leaching tests. The primary objective of this research is to determine typical source terms generated by commercial solidified low-level wastes. The field lysimeter facility consists of 10, 3 M deep by 1.8 M diameter, closed-bottomed lysimeters around a central 4 M deep by 4 M diameter instrument caisson. Commercial cement and dow polymer waste samples were removed from 210 L drums and placed in the 1.8 M diameter lysimeters. Two bitumen samples are planned to be emplaced in the facility this year. The central caisson provides access to the instrumentation in the individual lysimeters and allows selective sampling of the soil and waste forms. Suction candles (ceramic cups) placed around the waste will be used to periodically collect soil water samples for chemical analysis. Meteorological data, moisture content, and soil temperature are being automatically monitored at the facility. Characterization of the soils and waste forms have been partially completed. These data consist of moisture release characteristics, particle size distribution, concentrations and distributions of radionuclides in the waste streams, and concentrations of hydrophilic organic species in one of the waste streams

  7. Organic semiconductor rubrene thin films deposited by pulsed laser evaporation of solidified solutions

    Science.gov (United States)

    Majewska, N.; Gazda, M.; Jendrzejewski, R.; Majumdar, S.; Sawczak, M.; Śliwiński, G.

    2017-08-01

    Organic semiconductor rubrene (C42H28) belongs to most preferred spintronic materials because of the high charge carrier mobility up to 40 cm2(V·s)-1. However, the fabrication of a defect-free, polycrystalline rubrene for spintronic applications represents a difficult task. We report preparation and properties of rubrene thin films deposited by pulsed laser evaporation of solidified solutions. Samples of rubrene dissolved in aromatic solvents toluene, xylene, dichloromethane and 1,1-dichloroethane (0.23-1% wt) were cooled to temperatures in the range of 16.5-163 K and served as targets. The target ablation was provided by a pulsed 1064 nm or 266 nm laser. For films of thickness up to 100 nm deposited on Si, glass and ITO glass substrates, the Raman and AFM data show presence of the mixed crystalline and amorphous rubrene phases. Agglomerates of rubrene crystals are revealed by SEM observation too, and presence of oxide/peroxide (C42H28O2) in the films is concluded from matrix-assisted laser desorption/ionization time-of-flight spectroscopic analysis.

  8. Disposal and long-term storage in geological formations of solidified radioactive wastes

    International Nuclear Information System (INIS)

    Shischits, I.

    1996-01-01

    The special depository near Krasnoyarsk contains temporarily about 1,100 tons of spent nuclear fuel (SNF) from WWR- should be solidified and for the most part buried in geological formations. Solid wastes and SNF from RBMK reactors are assumed to be buried as well. For this purpose special technologies and underground constructions are required. They are to be created in the geological plots within the territory of Russian Federation and adjacent areas of CIS, meeting the developed list of requirements. The burial structures will vary greatly depending on the geological formation, the amount of wastes and their isotope composition. The well-known constructions such as deep wells, shafts, mines and cavities can be mentioned. There is a need to design constructions, which have no analog in the world practice. In the course of the Project fulfillment the following work will be conducted: -theoretical work followed by code creation for mathematical simulation of processes; - modelling on the base of prototypes made from equivalent materials with the help of simulators; - bench study; - experiments in real conditions; - examination of massif properties in particular plots using achievements of geophysics, including gamma-gamma density detectors and geo locators. Finally, ecological-economical model will be given for designing burial sites

  9. Evaluation of the performance of solidified commercial low-level wastes in an arid climate

    International Nuclear Information System (INIS)

    Graham, M.J.; Walter, M.B.

    1984-09-01

    Shallow land burial is being used as a disposal method for commercial low-level waste at waste disposal sites in arid (Hanford site near Richland, Washington) and humid (Barnwell, South Carolina) climatic regions. A field lysimeter facility has been established at the Hanford site in which to conduct waste-form leaching tests. The primary objective of this research is to determine typical source terms generated by commercial solidified low-level wastes. The field lysimeter facility consists of ten 3-m-deep by 1.8-m-diameter, closed-bottom lysimeters around a central instrument caisson, 4 m in diameter. Commercial cement and vinyl ester-styrene waste samples were removed from 210-L drums and placed in the 1.8-m-diameter lysimeters. Two bitumen samples are planned to be emplaced in the facility in 1984. The central caisson provides access to the instrumentation in the individual lysimeters and allows selective sampling of the soil and waste forms. Suction candles (ceramic cups) placed around the waste will be used to periodically collect soil water samples for chemical analysis. Meteorological data, moisture content, and soil temperature are automatically monitored at the facility. Characterization of the soils and waste forms have been partially completed. These data consist of moisture release characteristics, particle size distribution, concentrations and distributions of radionuclides in the waste forms, concentrations of radionuclides in the waste streams, and concentrations of hydrophilic organic species in one of the waste steams. 8 references, 3 figures, 5 tables

  10. On oscillatory microstructure during cellular growth of directionally solidified Sn–36at.%Ni peritectic alloy

    Science.gov (United States)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie

    2016-01-01

    An oscillatory microstructure has been observed during deep-cellular growth of directionally solidified Sn–36at.%Ni hyperperitectic alloy containing intermetallic compounds with narrow solubility range. This oscillatory microstructure with a dimension of tens of micrometers has been observed for the first time. The morphology of this wave-like oscillatory structure is similar to secondary dendrite arms, and can be observed only in some local positions of the sample. Through analysis such as successive sectioning of the sample, it can be concluded that this oscillatory microstructure is caused by oscillatory convection of the mushy zone during solidification. And the influence of convection on this oscillatory microstructure was characterized through comparison between experimental and calculations results on the wavelength. Besides, the change in morphology of this oscillatory microstructure has been proved to be caused by peritectic transformation during solidification. Furthermore, the melt concentration increases continuously during solidification of intermetallic compounds with narrow solubility range, which helps formation of this oscillatory microstructure. PMID:27066761

  11. Synthesis of laser beam rapidly solidified novel surfaces on D2 tool steel

    International Nuclear Information System (INIS)

    Ahmed, B.A.; Rizwan, K.F.; Minhas, J.A.; Waheed-ul-Haq, S.; Shahid, M.

    2011-01-01

    Surface layer of D2 tool steel was subjected to laser surface melting using continuous wave 2.5 kW CO/sub 2/ laser in point source melting mode. The processing parameters were varied to achieve a uniform depth of around 2 mm. Microstructural study revealed epitaxial growth of fine dendritic structure with secondary dendrite arm spacing in the range of 20-25 mu m. The phases in the parent annealed sample were BCC ferrite and chromium rich M7C3 carbide. The major phase after laser treatment was austenite and M7C3. The average hardness of annealed sample was 195 HV which increased to 410 HV after laser melting. Corrosion studies in 2% HCl solution exhibited a drastic improvement in corrosion resistance in laser treated samples. Improvement in properties is attributed to the refinement and uniformity of microstructure in the rapidly solidified surface. The case of a moving heat source was subjected to computer aided simulation to predict the melt depth at different processing conditions in point source melting mode. The calculated depths using the model, in ABAQUS software was found in good agreement with the experimental data. (author)

  12. Preparation and Stability of Inorganic Solidified Foam for Preventing Coal Fires

    Directory of Open Access Journals (Sweden)

    Botao Qin

    2014-01-01

    Full Text Available Inorganic solidified foam (ISF is a novel material for preventing coal fires. This paper presents the preparation process and working principle of main installations. Besides, aqueous foam with expansion ratio of 28 and 30 min drainage rate of 13% was prepared. Stability of foam fluid was studied in terms of stability coefficient, by varying water-slurry ratio, fly ash replacement ratio of cement, and aqueous foam volume alternatively. Light microscope was utilized to analyze the dynamic change of bubble wall of foam fluid and stability principle was proposed. In order to further enhance the stability of ISF, different dosage of calcium fluoroaluminate was added to ISF specimens whose stability coefficient was tested and change of hydration products was detected by scanning electron microscope (SEM. The outcomes indicated that calcium fluoroaluminate could enhance the stability coefficient of ISF and compact hydration products formed in cell wall of ISF; naturally, the stability principle of ISF was proved right. Based on above-mentioned experimental contents, ISF with stability coefficient of 95% and foam expansion ratio of 5 was prepared, which could sufficiently satisfy field process requirements on plugging air leakage and thermal insulation.

  13. High temperature low cycle fatigue behavior of a directionally solidified Ni-base superalloy DZ951

    International Nuclear Information System (INIS)

    Chu Zhaokuang; Yu Jinjiang; Sun Xiaofeng; Guan Hengrong; Hu Zhuangqi

    2008-01-01

    Total strain-controlled low cycle fatigue (LCF) tests were performed at a temperature range from 700 to 900 deg. C in ambient air condition on a directionally solidified Ni-base superalloy DZ951. The fatigue life of DZ951 alloy does not monotonously decrease with increasing temperature, but exhibits a strong dependence on the total strain range. The dislocation characteristics and failed surface observation were evaluated through transmission electron microscopy and scanning electron microscopy. The alloy exhibits cyclic hardening, softening or cyclic stability as a whole, which is dependent on the testing temperature and total strain range. At 700 deg. C, the cyclic plastic deformation process is the main cause of fatigue failure. At 900 deg. C, the failure mostly results from combined fatigue and creep damage under total strain range from 0.6 to 1.2% and the reduction in fatigue life can be taken as the cause of oxidation, creep and cyclic plastic deformation under total strain range of 0.5%

  14. Structural investigations of mechanical properties of Al based rapidly solidified alloys

    International Nuclear Information System (INIS)

    Karakoese, Ercan; Keskin, Mustafa

    2011-01-01

    Highlights: → Rapid solidification processing (RSP) involves exceptionally high cooling rates. → We correlate the microstructure of the intermetallic Al 3 Fe, Al 2 Cu and Al 3 Ni phases with the cooling rate. → The solidification rate is high enough to retain most of alloying elements in the Al matrix. → The rapid solidification has effect on the phase constitution. -- Abstract: In this study, Al based Al-3 wt.%Fe, Al-3 wt.%Cu and Al-3 wt.%Ni alloys were prepared by conventional casting. They were further processed using the melt-spinning technique and characterized by the X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), differential scanning calorimetry (DSC) and the Vickers microhardness tester. The rapidly solidified (RS) binary alloys were composed of supersaturated α-Al solid solution and finely dispersed intermetallic phases. Experimental results showed that the mechanical properties of RS alloys were enhanced, which can be attributed to significant changes in the microstructure. RS samples were measured using a microhardness test device. The dependence of microhardness H V on the solidification rate (V) was analysed. These results showed that with the increasing values of V, the values of H V increased. The enthalpies of fusion for the same alloys were determined by DSC.

  15. Comparison of ice particle morphology crushed from ice chunk and directly solidified from droplet

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.H.; Yoon, Y.S.; Bang, S.Y. [Dongguk Univ., Pil-dong, Chung-gu, Seoul (Korea, Republic of). Dept. of Mechanical Engineering

    2008-07-01

    In order to investigate the transition kinetics of ice to hydrate and to produce standard specimens of hydrate pellet from prepared hydrate powders, fine ice beads with uniform diameters must be fabricated. This paper discussed the construction of several experimental setups for the fabrication of fine ice particle generation. The ultrasonic nozzle was used to produce fine mist which solidified near the free surface of liquid nitrogen bath. The shape and population distribution of ice bead diameters was analyzed. The study also compared ice particles produced by crushing. The surface morphology of ice particles produced with a ball mill was also examined. Experimental results were obtained for an ice shaver, ball mill, bowl for grinding medicine, and ultrasonic nozzle. It was concluded that the information generated from the study was useful in estimating the macroscopic flow characteristics such as permeability of bulk powder and in determining mean effective diameter of irregular shaped particles. Future work was also noted as being underway with different experiments for other cases with different operating conditions. 5 refs., 5 figs.

  16. Electron microscopy investigations of rapidly solidified Fe-Zr-B-Cu alloys

    International Nuclear Information System (INIS)

    Majumdar, B.; Arvindha Babu, D.; Akhtar, D.

    2010-01-01

    Rapidly solidified Fe-based nanocrystalline soft magnetic materials possess a unique combination of properties i,e high permeability, saturation and Curie temperature and very low coercivity which are otherwise not attainable in conventional soft magnetic materials. The alloys are processed by producing amorphous phase through melt spinning route followed by a partial devitrification for incorporation of nanocrystalline phase in the amorphous matrix. In this paper, detailed electron microscopic investigations of melt spun Fe-Zr-B-Cu alloys are presented. Melt spun ribbons of Fe 99-x-y Zr x BCu 1 alloys with x+y = 11 and x+y = 13 were prepared under different wheel speed conditions and then vacuum annealed for 1 h at different temperatures. The microstructure changes from completely amorphous to a cellular/dendritic bcc solid solution coexisting with the amorphous phase at intercellular/dendritic regions when Zr/B ratio or the process parameters are varied. Annealing leads to the precipitation of nanocrystalline bcc-Fe phase from both amorphous phase and already existing bcc solid solution. (author)

  17. Particle Engulfment and Pushing by Solidifying Interfaces. Pt. 2; Micro-Gravity Experiments and Theoretical Analysis

    Science.gov (United States)

    Stefanescu, Doru M.; Juretzko, Frank R.; Dhindaw, Brij K.; Catalina, Adrian; Sen, Subhayu; Curreri, Peter A.

    1998-01-01

    Results of the directional solidification experiments on Particle Engulfment and Pushing by Solidifying Interfaces (PEP) conducted on the space shuttle Columbia during the Life and Microgravity Science Mission are reported. Two pure aluminum (99.999%) 9 mm cylindrical rods, loaded with about 2 vol.% 500 micrometers diameter zirconia particles were melted and resolidified in the microgravity (microg) environment of the shuttle. One sample was processed at step-wise increased solidification velocity, while the other at step-wise decreased velocity. It was found that a pushing-to-engulfment transition (PET) occurred in the velocity range of 0.5 to 1 micrometers. This is smaller than the ground PET velocity of 1.9 to 2.4 micrometers. This demonstrates that natural convection increases the critical velocity. A previously proposed analytical model for PEP was further developed. A major effort to identify and produce data for the surface energy of various interfaces required for calculation was undertaken. The predicted critical velocity for PET was of 0.775 micrometers/s.

  18. Evaluating Local Primary Dendrite Arm Spacing Characterization Techniques Using Synthetic Directionally Solidified Dendritic Microstructures

    Science.gov (United States)

    Tschopp, Mark A.; Miller, Jonathan D.; Oppedal, Andrew L.; Solanki, Kiran N.

    2015-10-01

    Microstructure characterization continues to play an important bridge to understanding why particular processing routes or parameters affect the properties of materials. This statement certainly holds true in the case of directionally solidified dendritic microstructures, where characterizing the primary dendrite arm spacing is vital to developing the process-structure-property relationships that can lead to the design and optimization of processing routes for defined properties. In this work, four series of simulations were used to examine the capability of a few Voronoi-based techniques to capture local microstructure statistics (primary dendrite arm spacing and coordination number) in controlled (synthetically generated) microstructures. These simulations used both cubic and hexagonal microstructures with varying degrees of disorder (noise) to study the effects of length scale, base microstructure, microstructure variability, and technique parameters on the local PDAS distribution, local coordination number distribution, bulk PDAS, and bulk coordination number. The Voronoi tesselation technique with a polygon-side-length criterion correctly characterized the known synthetic microstructures. By systematically studying the different techniques for quantifying local primary dendrite arm spacings, we have evaluated their capability to capture this important microstructure feature in different dendritic microstructures, which can be an important step for experimentally correlating with both processing and properties in single crystal nickel-based superalloys.

  19. The development of basic glass formulations for solidifying HLW from nuclear fuel reprocessing plant

    International Nuclear Information System (INIS)

    Jiang Yaozhong; Tang Baolong; Zhang Baoshan; Zhou Hui

    1995-01-01

    Basic glass formulations 90U/19, 90U/20, 90Nd/7 and 90Nd/10 applied in electric melting process are developed by using the mathematical model of the viscosity and electric resistance of waste glass. The yellow phase does not occur for basic glass formulations 90U/19 and 90U/20 solidifying HLW from nuclear fuel reprocessing plant when the waste loading is 20%. Under the waste loading is 16%, the process and product properties of glass 90U/19 and 90U/20 come up to or surpass the properties of the same kind of foreign waste glasses, and other properties are about the same to them of foreign waste glasses. The process and product properties of basic glass formulations 90Nd/7 and 90Nd/10 used for the solidification of 'U replaced by Nd' liquid waste are almost similar to them of 90U/19 and 90U/20. These properties fairly meet the requirements of 'joint test' (performed at KfK-INE, Germany). Among these formulations, 90Nd/7 is applied in cold engineering scale electric melting test performed at KfK-INE in Germany. The main process properties of cold test is similar to laboratory results

  20. Review of metal-matrix encapsulation of solidified radioactive high-level waste

    International Nuclear Information System (INIS)

    Jardine, L.J.; Steindler, M.J.

    1978-05-01

    Literature describing previous and current work on the encapsulation of solidified high-level waste forms in a metal matrix was reviewed. Encapsulation of either stabilized calcine pellets or glass beads in alloys by casting techniques was concluded to be the most developed and direct approach to fabricating solid metal-matrix waste forms. Further characterizations of the physical and chemical properties of metal-matrix waste forms are still needed to assess the net attributes of metal-encapsulation alternatives. Steady-state heat transfer properties of waste canisters in air and water environments were calculated for four reference waste forms: (1) calcine, (2) glass monoliths, (3) metal-encapsulated calcine, and (4) metal-encapsulated glass beads. A set of criteria for the maximum allowable canister centerline and surface temperatures and heat generation rates per canister at the time of shipment to a Federal repository was assumed, and comparisons were made between canisters of these reference waste forms of the shortest time after reactor discharge that canisters could be filled and the subsequent ''interim'' storage times prior to shipment to a Federal repository for various canister diameters and waste ages. A reference conceptual flowsheet based on existing or developing technology for encapsulation of stabilized calcine pellets is discussed. Conclusions and recommendations are presented

  1. Leaching behaviour and mechanical properties of copper flotation waste in stabilized/solidified products.

    Science.gov (United States)

    Mesci, Başak; Coruh, Semra; Ergun, Osman Nuri

    2009-02-01

    This research describes the investigation of a cement-based solidification/stabilization process for the safe disposal of copper flotation waste and the effect on cement properties of the addition of copper flotation waste (CW) and clinoptilolite (C). In addition to the reference mixture, 17 different mixtures were prepared using different proportions of CW and C. Physical properties such as setting time, specific surface area and compressive strength were determined and compared to a reference mixture and Turkish standards (TS). Different mixtures with the copper flotation waste portion ranging from 2.5 to 12.5% by weight of the mixture were tested for copper leachability. The results show that as cement replacement materials especially clinoptilolite had clear effects on the mechanical properties. Substitution of 5% copper flotation waste for Portland cement gave a similar strength performance to the reference mixture. Higher copper flotation waste addition such as 12.5% replacement yielded lower strength values. As a result, copper flotation waste and clinoptilolite can be used as cementitious materials, and copper flotation waste also can be safely stabilized/solidified in a cement-based solidification/stabilization system.

  2. Measurements of Mercury Released From Solidified/Stabilized Waste Forms-FY2002

    International Nuclear Information System (INIS)

    Mattus, C.H.

    2003-01-01

    This report covers work performed during FY 2002 in support of treatment demonstrations conducted for the U.S. Department of Energy (DOE) Mixed Waste Focus Area (MWFA) Mercury Working Group. To comply with the requirements of the Resource Conservation and Recovery Act, as implemented by the U.S. Environmental Protection Agency (EPA), DOE must use one of the following procedures for mixed low-level radioactive wastes containing mercury at levels above 260 ppm: a retorting/roasting treatment or (if the wastes also contain organics) an incineration treatment. The recovered radioactively contaminated mercury must then be treated by an amalgamation process prior to disposal. The DOE MWFA Mercury Working Group is working with EPA to determine whether some alternative processes could be used to treat these types of waste directly, thereby avoiding a costly recovery step for DOE. In previous years, demonstrations were performed in which commercial vendors applied their technologies for the treatment of radiologically contaminated elemental mercury as well as radiologically contaminated and mercury-contaminated waste soils from Brookhaven National Laboratory. The test results for mercury release in the headspace were reported in two reports, ''Measurements of Mercury Released from Amalgams and Sulfide Compounds'' (ORNL/TM-13728) and ''Measurements of Mercury Released from Solidified/Stabilized Waste Forms'' (ORNL/TM-2001/17). The current work did not use a real waste; a surrogate sludge had been prepared and used in the testing in an effort to understand the consequences of mercury speciation on mercury release

  3. Strength, leachability and microstructure characteristics of cement-based solidified plating sludge

    International Nuclear Information System (INIS)

    Asavapisit, Suwimol; Naksrichum, Siripat; Harnwajanawong, Naraporn

    2005-01-01

    The solidification of the stabilized zinc-cyanide plating sludge was carried out using ordinary Portland cement (OPC) and pulverized fuel ash (PFA) as solidification binders. The plating sludge were used at the level of 0%, 10%, 20% and 30% dry weight, and PFA was used to replace OPC at 0%, 10%, 20% and 30% dry weight, respectively. Experimental results showed that a significant reduction in strength was observed when the plating sludge was added to both the OPC and OPC/PFA binders, but the negative effect was minimized when PFA was used as part substitute for OPC. SEM observation reveals that the deposition of the plating sludge on the surface of the clinkers and PFA could be the cause for hydration retardation. In addition, calcium zinc hydroxide hydrate complex and the unreacted di- and tricalcium silicates were the major phases in X-ray diffraction (XRD) patterns of the solidified plating waste hydrated for 28 days, although the retardation effect on hydration reactions but Cr concentration in toxicity characteristic leaching procedure (TCLP) leachates was lower than the U.S. EPA regulatory limit

  4. Testing and evaluation of solidified high-level waste forms. Joint annual progress report 1983

    International Nuclear Information System (INIS)

    Malow, G.

    1985-01-01

    A second joint programme of the European Atomic Community was started in 1981 under the indirect action programme (1980-84), Action No 5 'Testing and evaluation of the properties of various potential materials for immobilizing high activity waste'. The overall objective of the research is to test various European potential solidified high-level radioactive waste forms so as to predict their behaviour after disposal. The most important aspect is to produce data to calculate the activity release from the waste products under the attack of various aqueous solutions. The experiments were partly performed under waste repository relevant conditions and partly under simplified conditions for investigating basic activity release mechanisms. The topics of the programme were: (i) studies of basic leaching mechanisms; (ii) studies of hydrothermal leaching and surface attack of waste glasses; (iii) leach test carried out in contact with granite at low water flow rates; (iv) static leach tests with specimen surrounded by canister and backfill materials; (v) specific isotope leach tests in slowly flowing water; (vi) leach test of actinide spiked samples; (vii) leach tests of highly radioactive samples; (viii) leach tests of alpha radiation stability; (ix) studies of mechanical stability; (x) studies of mineral phases as model compounds and phase relations

  5. Decomposition for the analysis of radionuclides in solidified cement radioactive waste

    International Nuclear Information System (INIS)

    Lee, Jeong Jin; Pyo, Hyung Yeal; Jee, Kwang Yung; Jeon, Jong Seon

    2004-01-01

    Spent ion exchange resins make solid radioactive wastes when mixed with cement as solidifying material that was widely used in securing human environment from radionuclides for at least hundreds years. The cumulative increase of low and medium level radioactive wastes results in capacity problem of temporary storage in some NPPs (Nuclear Power Plants) of Korea around 2008. Radioactive wastes are scheduled to be disposed in a permanent disposal facility in accordance with the Korean Radioactive Wastes Management Program. It is mandatory to identify kinds and concentration of radionuclides immobilized for transporting them from temporary storage in NPPs to disposal facility. Accordingly, the effective sample decomposition prior to radiochemical separation is prerequisite to obtain the analytical data about radionuclides in cement waste forms. The closed-vessel microwave digestion technology among several sample preparation methods is taken into account to decompose cement waste forms. In this study, SRM 1880a (Portland cement) which is known for its certified values was used to optimize decomposition condition of cement waste forms containing nonradioactive ion exchange resins from NPP. With such variables as reagents, time, and power, the variation of the transparency and the color of the solution after closed-vessel microwave digestion can be examine. SRM 1880a is decomposed by suggested digestion procedure and the recoveries of constituents were investigated by ICP-AES and AAS

  6. Giant Enhancement of Magnetostrictive Response in Directionally-Solidified Fe83Ga17Erx Compounds

    Directory of Open Access Journals (Sweden)

    Radhika Barua

    2018-06-01

    Full Text Available We report, for the first time, correlations between crystal structure, microstructure and magnetofunctional response in directionally solidified [110]-textured Fe83Ga17Erx (0 < x < 1.2 alloys. The morphology of the doped samples consists of columnar grains, mainly composed of a matrix phase and precipitates of a secondary phase deposited along the grain boundary region. An enhancement of more than ~275% from ~45 to 170 ppm is observed in the saturation magnetostriction value (λs of Fe83Ga17Erx alloys with the introduction of small amounts of Er. Moreover, it was noted that the low field derivative of magnetostriction with respect to an applied magnetic field (i.e., dλs/dHapp for Happ up to 1000 Oe increases by ~230% with Er doping (dλs/dHapp,FeGa= 0.045 ppm/Oe; dλs/dHapp,FeGaEr= 0.15 ppm/Oe. The enhanced magnetostrictive response of the Fe83Ga17Erx alloys is ascribed to an amalgamation of microstructural and electronic factors, namely: (i improved grain orientation and local strain effects due to deposition of Er in the intergranular region; and (ii strong local magnetocrystalline anisotropy, due to the highly anisotropic localized nature of the 4f electronic charge distribution of the Er atom. Overall, this work provides guidelines for further improving galfenol-based materials systems for diverse applications in the power and energy sector.

  7. Short-term thermal response of rapidly solidified Type 304 stainless steel containing helium

    International Nuclear Information System (INIS)

    Clark, D.E.

    1988-06-01

    Type 304 stainless steel was heat treated for short times near its melting point in order to determine its microstructural response to thermal cycles typical of the near heat-affected zones of welding processes. The material was rapidly solidified as a powder by centrifugal atomization in a helium environment and consolidated by hot extrusion. Along with the ingot metallurgy material used for canning the powder prior to hot extrusion, it was heat treated using a Gleeble at temperatures of 1200 and 1300 degree C for times ranging from <1 to 1000 s, and the samples were examined for microstructure and the existence of porosity due to entrapped helium. At higher test temperatures and longer treatment times, the material developed extensive porosity, which was stabilized by the presence of helium and which may also have a role in anchoring grain boundaries and inhibiting grain growth. The powder material. At lower test temperatures and shorter treatment times, grain growth in the γ phase appeared to be restricted in the powder material, possible by the presence of helium. An intermediate temperatures and times, a γ-δ duplex microstructure also restricted grain growth again occurred in the δ microstructure. 9 refs., 14 figs., 3 tabs

  8. A study of accelerated radiation damage effects in PuO{sub 2} and gadolinia-stabilized cubic zirconia, Zr{sub 0.79}Gd{sub 0.14}Pu{sub 0.07}O{sub 1.93}, doped with {sup 238}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Burakov, B.E., E-mail: burakov@peterlink.ru [V.G. Khlopin Radium Institute, 28, 2-nd Murinskiy Ave., St. Petersburg, 194021 (Russian Federation); Yagovkina, M.A. [A.F. Ioffe Physical-Technical Institute, 26, Politekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

    2015-12-15

    Polycrystalline samples of cubic zirconia, Zr{sub 0.79}Gd{sub 0.14}Pu{sub 0.07}O{sub 1.93}, doped with approximately 9.9 wt.% {sup 238}Pu, and PuO{sub 2} containing 11.0 wt. % {sup 238}Pu (and main isotope is {sup 239}Pu) have been repeatedly studied during many years by X-ray diffraction analysis. At a temperature of 25 °C the unit-cell parameter of PuO{sub 2} increases depending on accumulated dose, and is accompanied by decrease of coherent scattering region (CSR). Self-irradiation of Zr{sub 0.79}Gd{sub 0.14}Pu{sub 0.07}O{sub 1.93} is accompanied with repeated change of unit-cell parameter and CSR.

  9. Ultrasensitive determination of mercury in human saliva by atomic fluorescence spectrometry based on solidified floating organic drop microextraction

    International Nuclear Information System (INIS)

    Yuan, C.-G.; Wang, J.; Jin, Y.

    2012-01-01

    We report on a new, rapid and simple method for the determination of ultra-trace quantities of mercury ion in human saliva. It is based on solidified floating organic drop microextraction and detection by cold vapor atomic fluorescence spectrometry (CV-AFS). Mercury ion was complexed with diethyldithiocarbamate, and the hydrophobic complex was then extracted into fine droplets of 1-undecanol. By cooling in an ice bath after extraction, the droplets in solution solidify to form a single ball floating on the surface of solution. The solidified micro drop containing the mercury complex was then transferred for determination by CV-AFS. The effects of pH value, concentration of chelating reagent, quantity of 1-undecanol, sample volume, equilibration temperature and time were investigated. Under the optimum conditions, the preconcentration of a 25-mL sample is accomplished with an enrichment factor of 182. The limit of detection is 2.5 ng L -1 . The relative standard deviation for seven replicate determinations at 0.1 ng mL -1 level is 4.1%. The method was applied to the determination of mercury in saliva samples collected from four volunteers. Two volunteers having dental amalgam fillings had 0.4 ng mL -1 mercury in their saliva, whereas mercury was not detectable in the saliva of two volunteers who had no dental fillings. (author)

  10. Precipitation in as-solidified undercooled Ni-Si hypoeutectic alloy: Effect of non-equilibrium solidification

    International Nuclear Information System (INIS)

    Fan Kai; Liu Feng; Yang Gencang; Zhou Yaohe

    2011-01-01

    Highlights: → The solid solubility of Si atom in α-Ni matrix increased with undercooling in the as-solidified sample. → The effect of non-equilibrium solidification on precipitation has been theoretically described. → The nucleation density, the real-time particle size and the precipitation rate are all increased upon annealing. → The precipitate process can be artificially controlled by modifying the initial melt undercooling and the annealing time. - Abstract: Applying glass fluxing and cyclic superheating, high undercooling up to ∼350 K was achieved for Ni-Si hypoeutectic alloy melt. By isothermally annealing the as-solidified alloy subjected to different undercoolings, precipitation behavior of Ni 3 Si particle, at 973 K, was systematically studied. It was found that, the nucleation density and the real-time particle size, as well as the precipitation rate, were all increased, provided the sample was solidified subjected to higher undercooling. This was ascribed mainly to the increased solid solubility of Si atom in α-Ni matrix upon non-equilibrium solidification. On this basis, the non-equilibrium dendrite growth upon solidification and the soft impingement prevailing upon solid-state precipitation have been quantitatively connected. As such, the effect of liquid/solid transformation on subsequent precipitation was described.

  11. Development of methodology to evaluate microbially influenced degradation of cement-solidified low-level radioactive waste forms

    International Nuclear Information System (INIS)

    Rogers, R.D.; Hamilton, M.A.; Veeh, R.H.; McConnell, J.W.

    1994-01-01

    Because of its apparent structural integrity, cement has been widely used in the United States as a binder to solidify Class B and C low-level radioactive waste (LLW). However, the resulting cement preparations are susceptible to failure due to the actions of stress and environment. An environmentally mediated process that could affect cement stability is the action of naturally occurring microorganisms. The US Nuclear Regulatory Commission (NRC), recognizing this eventuality, stated that the effects of microbial action on waste form integrity must be addressed. This paper provides present results from an ongoing program that addresses the effects of microbially influenced degradation (MID) on cement-solidified LLW. Data are provided on the development of an evaluation method using acid-producing bacteria. Results are from work with one type of these bacteria, the sulfur-oxidizing Thiobacillus. This work involved the use of a system in which laboratory- and vendor-manufactured, simulated waste forms were exposed on an intermittent basis to media containing thiobacilli. Testing demonstrated that MID has the potential to severely compromise the structural integrity of ion-exchange resin and evaporator-bottoms waste that is solidified with cement. In addition, it was found that a significant percentage of calcium and other elements were leached from the treated waste forms. Also, the surface pH of the treated specimens decreased to below 2. These conditions apparently contributed to the physical deterioration of simulated waste forms after 60 days of exposure to the thiobacilli

  12. Precipitation in as-solidified undercooled Ni-Si hypoeutectic alloy: Effect of non-equilibrium solidification

    Energy Technology Data Exchange (ETDEWEB)

    Fan Kai [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Liu Feng, E-mail: liufeng@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Yang Gencang; Zhou Yaohe [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China)

    2011-08-25

    Highlights: {yields} The solid solubility of Si atom in {alpha}-Ni matrix increased with undercooling in the as-solidified sample. {yields} The effect of non-equilibrium solidification on precipitation has been theoretically described. {yields} The nucleation density, the real-time particle size and the precipitation rate are all increased upon annealing. {yields} The precipitate process can be artificially controlled by modifying the initial melt undercooling and the annealing time. - Abstract: Applying glass fluxing and cyclic superheating, high undercooling up to {approx}350 K was achieved for Ni-Si hypoeutectic alloy melt. By isothermally annealing the as-solidified alloy subjected to different undercoolings, precipitation behavior of Ni{sub 3}Si particle, at 973 K, was systematically studied. It was found that, the nucleation density and the real-time particle size, as well as the precipitation rate, were all increased, provided the sample was solidified subjected to higher undercooling. This was ascribed mainly to the increased solid solubility of Si atom in {alpha}-Ni matrix upon non-equilibrium solidification. On this basis, the non-equilibrium dendrite growth upon solidification and the soft impingement prevailing upon solid-state precipitation have been quantitatively connected. As such, the effect of liquid/solid transformation on subsequent precipitation was described.

  13. Evaluation of physical stability and leachability of Portland Pozzolona Cement (PPC) solidified chemical sludge generated from textile wastewater treatment plants

    International Nuclear Information System (INIS)

    Patel, Hema; Pandey, Suneel

    2012-01-01

    Highlights: ► Stabilization/solidification of chemical sludge from textile wastewater treatment plants using Portland Pozzolona Cement (PPC) containing fly ash. ► Physical engineering (compressive strength and block density) indicates that sludge has potential to be reused for construction purpose after stabilization/solidification. ► Leaching of heavy metals from stabilized/solidified materials were within stipulated limits. ► There is a modification of microstructural properties of PPC with sludge addition as indicated by XRD and SEM patterns. - Abstract: The chemical sludge generated from the treatment of textile dyeing wastewater is a hazardous waste as per Indian Hazardous Waste Management rules. In this paper, stabilization/solidification of chemical sludge was carried out to explore its reuse potential in the construction materials. Portland Pozzolona Cement (PPC) was selected as the binder system which is commercially available cement with 10–25% fly ash interground in it. The stabilized/solidified blocks were evaluated in terms of unconfined compressive strength, block density and leaching of heavy metals. The compressive strength (3.62–33.62 MPa) and block density (1222.17–1688.72 kg/m 3 ) values as well as the negligible leaching of heavy metals from the stabilized/solidified blocks indicate that there is a potential of its use for structural and non-structural applications.

  14. In situ DRIFTs investigation of the reaction mechanism over MnO{sub x}-MO{sub y}/Ce{sub 0.75}Zr{sub 0.25}O{sub 2} (M = Fe, Co, Ni, Cu) for the selective catalytic reduction of NO{sub x} with NH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Hang; Zha, Kaiwen; Li, Hongrui; Shi, Liyi; Zhang, Dengsong, E-mail: dszhang@shu.edu.cn

    2016-11-30

    Highlights: • MnO{sub x}-FeO{sub y}/Ce{sub 0.75}Zr{sub 0.25}O{sub 2} catalyst has a strong NO oxidation ability. • A high dispersion of active components is achieved on catalyst surface. • At high temperatures, bidentate nitrate is the common active species. • The addition of Fe can improve the reactivity of gaseous NO{sub 2} and bridged nitrates. - Abstract: A series of MnO{sub x}-MO{sub y}/Ce{sub 0.75}Zr{sub 0.25}O{sub 2} (M = Fe, Co, Ni, Cu) catalysts were synthesized by an impregnation method and used for selective catalytic reduction (SCR) of NO{sub x} with NH{sub 3}. The catalytic performances of various MnO{sub x}-MO{sub y}/Ce{sub 0.75}Zr{sub 0.25}O{sub 2} catalysts were studied. It was found that MnO{sub x}-FeO{sub y}/Ce{sub 0.75}Zr{sub 0.25}O{sub 2} catalyst showed excellent low-temperature activity and a broad temperature window. The catalysts were characterized by N{sub 2} adsorption/desorption, X-ray diffraction, X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared transform spectroscopy (DRIFTS). Characterization of the catalyst confirmed the addition of iron oxide can enhance the NO oxidation ability of the catalyst which results in the outstanding low-temperature SCR activity. Meanwhile, iron oxides were well dispersed on catalyst surface which could avoid the agglomeration of active species, contributing to the strong interaction between active species and the support. More importantly, in situ DRIFTS results confirmed that bidentate nitrates are general active species on these catalysts, whereas the reactivity of gaseous NO{sub 2} and bridged nitrates got improved because of the addition of Fe.

  15. Modeling of zinc solubility in stabilized/solidified electric arc furnace dust

    International Nuclear Information System (INIS)

    Fernandez-Olmo, Ignacio; Lasa, Cristina; Irabien, Angel

    2007-01-01

    Equilibrium models which attempt for the influence of pH on the solubility of metals can improve the dynamic leaching models developed to describe the long-term behavior of waste-derived forms. In addition, such models can be used to predict the concentration of metals in equilibrium leaching tests at a given pH. The aim of this work is to model the equilibrium concentration of Zn from untreated and stabilized/solidified (S/S) electric arc furnace dust (EAFD) using experimental data obtained from a pH-dependence leaching test (acid neutralization capacity, ANC). EAFD is a hazardous waste generated in electric arc furnace steel factories; it contains significant amounts of heavy metals such as Zn, Pb, Cr or Cd. EAFD from a local factory was characterized by X-ray fluorescence (XRF), acid digestion and X-ray diffraction (XRD). Zn and Fe were the main components while the XRD analysis revealed that zincite, zinc ferrite and hematite were the main crystalline phases. Different cement/EAFD formulations ranging from 7 to 20% dry weight of cement were prepared and subjected to the ANC leaching test. An amphoteric behavior of Zn was found from the pH dependence test. To model this behavior, the geochemical model Visual MINTEQ (VMINTEQ) was used. In addition to the geochemical model, an empirical model based on the dissolution of Zn in the acidic zone and the re-dissolution of zinc compounds in the alkaline zone was considered showing a similar prediction than that obtained with VMINTEQ. This empirical model seems to be more appropriate when the metal speciation is unknown, or when if known, the theoretical solid phases included in the database of VMINTEQ do not allow to describe the experimental data

  16. Solidified structure and leaching properties of metallurgical wastewater treatment sludge after solidification/stabilization process.

    Science.gov (United States)

    Radovanović, Dragana Đ; Kamberović, Željko J; Korać, Marija S; Rogan, Jelena R

    2016-01-01

    The presented study investigates solidification/stabilization process of hazardous heavy metals/arsenic sludge, generated after the treatment of the wastewater from a primary copper smelter. Fly ash and fly ash with addition of hydrated lime and Portland composite cement were studied as potential binders. The effectiveness of the process was evaluated by unconfined compressive strength (UCS) testing, leaching tests (EN 12457-4 and TCLP) and acid neutralization capacity (ANC) test. It was found that introduction of cement into the systems increased the UCS, led to reduced leaching of Cu, Ni and Zn, but had a negative effect on the ANC. Gradual addition of lime resulted in decreased UCS, significant reduction of metals leaching and high ANC, due to the excess of lime that remained unreacted in pozzolanic reaction. Stabilization of more than 99% of heavy metals and 90% of arsenic has been achieved. All the samples had UCS above required value for safe disposal. In addition to standard leaching tests, solidificates were exposed to atmospheric conditions during one year in order to determine the actual leaching level of metals in real environment. It can be concluded that the EN 12457-4 test is more similar to the real environmental conditions, while the TCLP test highly exaggerates the leaching of metals. The paper also presents results of differential acid neutralization (d-AN) analysis compared with mineralogical study done by scanning electron microscopy and X-ray diffraction analysis. The d-AN coupled with Eh-pH (Pourbaix) diagrams were proven to be a new effective method for analysis of amorphous solidified structure.

  17. Recycling stabilised/solidified drill cuttings for forage production in acidic soils.

    Science.gov (United States)

    Kogbara, Reginald B; Dumkhana, Bernard B; Ayotamuno, Josiah M; Okparanma, Reuben N

    2017-10-01

    Stabilisation/solidification (S/S), which involves fixation and immobilisation of contaminants using cementitious materials, is one method of treating drill cuttings before final fate. This work considers reuse of stabilised/solidified drill cuttings for forage production in acidic soils. It sought to improve the sustainability of S/S technique through supplementation with the phytoremediation potential of plants, eliminate the need for landfill disposal and reduce soil acidity for better plant growth. Drill cuttings with an initial total petroleum hydrocarbon (TPH) concentration of 17,125 mg kg -1 and low concentrations of metals were treated with 5%, 10%, and 20% cement dosages. The treated drill cuttings were reused in granular form for growing a forage, elephant grass (Pennisetum purpureum), after mixing with uncontaminated soil. The grasses were also grown in uncontaminated soil. The phytoremediation and growth potential of the plants was assessed over a 12-week period. A mix ratio of one part drill cuttings to three parts uncontaminated soil was required for active plant growth. The phytoremediation ability of elephant grass (alongside abiotic losses) reduced the TPH level (up to 8795 mg kg -1 ) in the soil-treated-drill cuttings mixtures below regulatory (1000 mg kg -1 ) levels. There were also decreased concentrations of metals. The grass showed better heights and leaf lengths in soil containing drill cuttings treated with 5% cement dosage than in uncontaminated soil. The results suggest that recycling S/S treated drill cuttings for forage production may be a potential end use of the treated waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Simulation and experiment for oxygen-enriched combustion engine using liquid oxygen to solidify CO2

    Science.gov (United States)

    Liu, Yongfeng; Jia, Xiaoshe; Pei, Pucheng; Lu, Yong; Yi, Li; Shi, Yan

    2016-01-01

    For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation (EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

  19. Time-dependent performance of soil mix technology stabilized/solidified contaminated site soils.

    Science.gov (United States)

    Wang, Fei; Wang, Hailing; Al-Tabbaa, Abir

    2015-04-09

    This paper presents the strength and leaching performance of stabilized/solidified organic and inorganic contaminated site soil as a function of time and the effectiveness of modified clays applied in this project. Field trials of deep soil mixing application of stabilization/solidification (S/S) were performed at a site in Castleford in 2011. A number of binders and addictives were applied in this project including Portland cement (PC), ground granulated blastfurnace slag (GGBS), pulverised fuel ash (PFA), MgO and modified clays. Field trial samples were subjected to unconfined compressive strength (UCS), BS CN 12457 batch leaching test and the extraction of total organics at 28 days and 1.5 years after treatment. The results of UCS test show that the average strength values of mixes increased from 0-3250 kPa at 28 days to 250-4250 kPa at 1.5 years curing time. The BS EN 12457 leachate concentrations of all metals were well below their drinking water standard, except Ni in some mixes exceed its drinking water standard at 0.02 mg/l, suggesting that due to varied nature of binders, not all of them have the same efficiency in treating contaminated soil. The average leachate concentrations of total organics were in the range of 20-160 mg/l at 28 days after treatment and reduced to 18-140 mg/l at 1.5 years. In addition, organo clay (OC)/inorgano-organo clay (IOC) slurries used in this field trial were found to have a negative effect on the strength development, but were very effective in immobilizing heavy metals. The study also illustrates that the surfactants used to modify bentonite in this field trail were not suitable for the major organic pollutants exist in the site soil in this project. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Fabrication of All-Solid-State Lithium-Ion Cells Using Three-Dimensionally Structured Solid Electrolyte Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} Pellets

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, Mao; Munakata, Hirokazu; Kanamura, Kiyoshi, E-mail: kanamura@tmu.ac.jp [Department of Applied Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Tokyo (Japan)

    2016-08-30

    All-solid-state lithium-ion batteries using Li{sup +}-ion conducting ceramic electrolytes have been focused on as attractive future batteries for electric vehicles and renewable energy conversion systems because high safety can be realized due to non-flammability of ceramic electrolytes. In addition, a higher volumetric energy density than that of current lithium-ion batteries is expected since the all-solid-state lithium-ion batteries can be made in bipolar cell configurations. However, the special ideas and techniques based on ceramic processing are required to construct the electrochemical interface for all-solid-state lithium-ion batteries since the battery development has been done so far based on liquid electrolyte system over 100 years. As one of the promising approaches to develop practical all-solid-state batteries, we have been focusing on three-dimensionally (3D) structured cell configurations such as an interdigitated combination of 3D pillars of cathode and anode, which can be realized by using solid electrolyte membranes with hole-array structures. The application of such kinds of 3D structures effectively increases the interface between solid electrode and solid electrolyte per unit volume, lowering the internal resistance of all-solid-state lithium-ion batteries. In this study, Li{sub 6.25}Al{sub 0.25}La{sub 3}Zr{sub 2}O{sub 12} (LLZAl), which is a Al-doped Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZ) with Li{sup +}-ion conductivity of ~10{sup –4} S ⋅cm{sup −1} at room temperature and high stability against lithium-metal, was used as a solid electrolyte, and its pellets with 700 μm depth holes in 700 μm × 700 μm area were fabricated to construct 3D-structured all-solid-state batteries with LiCoO{sub 2}/LLZAl/lithium-metal configuration. It is expected that the LiCoO{sub 2}–LLZAl interface is formed by point-to-point contact even when the LLZAl pellet with 3D hole-array structure is applied. Therefore, Li{sub 3}BO{sub 3}, which is a

  1. Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} metallic glass for potential use in dental implants: Biocompatibility assessment by in vitro cellular responses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing [School of Stomatology, China Medical University, 117 Nanjing North Sreet, Shenyang, 110002 (China); Shi, Ling-ling; Zhu, Zhen-dong; He, Qiang [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Ai, Hong-jun, E-mail: aih0620@yahoo.com.cn [School of Stomatology, China Medical University, 117 Nanjing North Sreet, Shenyang, 110002 (China); Xu, Jian, E-mail: jianxu@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China)

    2013-05-01

    In comparison with titanium and its alloys, Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} (ZT1) bulk metallic glass (BMG) manifests a good combination of high strength, high fracture toughness and lower Young's modulus. To examine its biocompatibility required for potential use in dental implants, this BMG was used as a cell growth subtract for three types of cell lines, L929 fibroblasts, human umbilical vein endothelial cells (HUVEC), and osteoblast-like MG63 cells. For a comparison, these cell lines were in parallel cultured and grown also on commercially pure titanium (CP-Ti) and Ti6–Al4–V alloy (Ti64). Cellular responses on the three metals, including adhesion, morphology and viability, were characterized using the SEM visualization and CCK-8 assay. Furthermore, real-time RT-PCR was used to measure the activity of integrin β, alkaline phosphatase (ALP) and type I collagen (COL I) in adherent MG63 cells. As indicated, in all cases of three cell lines, no significant differences in the initial attachment and viability/proliferation were found between ZT1, CP-Ti, and Ti64 until 5 d of incubation period. It means that the biocompatibility in cellular response for ZT1 BMG is comparable to Ti and its alloys. For gene expression of integrin β, ALP and COL I, mRNA level from osteoblast cells grown on ZT1 substrates is significantly higher than that on the CP-Ti and Ti64. It suggests that the adhesion and differentiation of osteoblasts grown on ZT1 are even superior to those on the CP-Ti and Ti64 alloy, then promoting bone formation. The good biocompatibility of ZT1 BMG is associated with the formation of zirconium oxide layer on the surface and good corrosion-resistance in physiological environment. Quantitative analysis of Real-time PCR for MG63 cells cultured on Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} BMG, CP-Ti, and Ti64 as well as plastic as a control at several incubation periods. Relative amounts of (a) integrin β, (b) ALP, and (c) COL I (*p < 0

  2. Synthesis and mechanical properties of bulk Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy fabricated by consolidation of mechanically alloyed amorphous powders

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xinfu; Wang, Kun; Li, Zhendong; Wang, Xingfu; Wang, Dan; Han, Fusheng, E-mail: fshan@issp.ac.cn

    2015-05-25

    Graphical abstract: Different regions indentation morphologies under 50 g load consolidated at 723 K (left), nanohardness of the Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} alloy as a function consolidation temperature (right). It can be seen from the above figures that the consolidated sample presents white regions, and the microhardness in the white regions is a little lower than the matrix, which could be caused by the difference of the chemical composition and chemical bonding forces between them. Interestingly, the cracks were formed around the indentation periphery in the white regions, which are not shown in the matrix. The nanohardness of the bulk composites increased from 11.16 to 13.27 GPa with the consolidation temperature increasing, mechanical softening was also found in the present alloys. - Highlights: • Bulk amorphous–nanocrystalline Al-based alloys were prepared by HPS process. • The Vickers microhardness of bulk samples is in the range of 945–1177HV0.1. • The nanohardness agrees well with the Vickers hardness testing results. - Abstract: Mechanically alloyed amorphous Al{sub 76}Ni{sub 8}Ti{sub 8}Zr{sub 4}Y{sub 4} (at.%) alloy powder was consolidated by high-pressure sintering process. The influence of the consolidation temperature on the structure and mechanical properties of the consolidated bulk alloys was examined by X-ray diffraction (XRD), Optical microscopy (OM), Scanning electron microscopy (SEM), Vickers Hardness Tester and Nano Indenter. Structural investigations of the bulk materials revealed that most of the amorphous structure was retained after consolidation at 623 K, however, compaction at 723 K and 823 K caused crystallization of the amorphous phase with the appearance of white regions. The results also indicate that application of high pressure affected the crystallization products of the present alloy. Micro mechanical analysis showed that the microhardness of the bulk composites increased from 945HV{sub 0.1} to 1177HV

  3. Investigation on microstructure characterization and property of rapidly solidified Mg-Zn-Ca-Ce-La alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Tao, E-mail: tzhou1118@163.com [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Chen Zhenhua, E-mail: chenzhenhua45@hotmail.com [College of Material Science and Engineering, Hunan University, Changsha 410082 (China); Yang Mingbo, E-mail: yangmingbo@cqit.edu.cn [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Hu Jianjun, E-mail: hujj@qq.com [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China); Xia Hua, E-mail: xiahua@cqut.edu.cn [College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400054 (China)

    2012-01-15

    Rapidly solidified (RS) Mg-Zn-Ca-Ce-La (wt.%) alloys have been produced via atomizing the alloy melt and subsequent splat-quenching on the water-cooled copper twin-rollers in the form of flakes. Microstructure characterization, phase compositions and thermal stability of the alloys have been systematically investigated. The results showed that with addition of RE (Ce and La) to the Mg-6Zn-5Ca alloy, the stable intermetallic compounds i.e. the Mg{sub x}Zn{sub y}RE{sub z} phase with a few Ca (about 3 at.%), shortened as the T Prime phase, were formed at the expense of the binary Mg-Zn and Ca{sub 2}Mg{sub 6}Zn{sub 3} phases, which was possibly beneficial to the enhanced thermal stability of the alloy. In the Mg-6Zn-5Ca-3Ce-0.5La alloy, the composition of the T Prime phase in the grain interior was different from that at the grain boundaries, in which the segregation of the La elements was found, and the atomic percentage ratio of Zn to Ce in the T Prime phase within the grains was close to 2. Moreover, the stable Mg{sub 2}Ca phases were detected around the T Prime phases at the grain boundaries in the alloy. - Research Highlights: Black-Right-Pointing-Pointer The phase constitution of RS Mg-6Zn-5Ca alloy can be improved by RE additions. Black-Right-Pointing-Pointer In the Mg-Zn-Ca-Ce-La alloys, the Mg{sub x}Zn{sub y}RE{sub z} phase with a few Ca (T Prime phase) is formed. Black-Right-Pointing-Pointer The formation of the T Prime phase leads to the loss of the Mg-Zn and Ca{sub 2}Mg{sub 6}Zn{sub 3} phases. Black-Right-Pointing-Pointer The composition of the T Prime phase differs from the grain interior to the grain boundary.

  4. Crack initiation modeling of a directionally-solidified nickel-base superalloy

    Science.gov (United States)

    Gordon, Ali Page

    Combustion gas turbine components designed for application in electric power generation equipment are subject to periodic replacement as a result of cracking, damage, and mechanical property degeneration that render them unsafe for continued operation. In view of the significant costs associated with inspecting, servicing, and replacing damaged components, there has been much interest in developing models that not only predict service life, but also estimate the evolved microstructural state of the material. This thesis explains manifestations of microstructural damage mechanisms that facilitate fatigue crack nucleation in a newly-developed directionally-solidified (DS) Ni-base superalloy components exposed to elevated temperatures and high stresses. In this study, models were developed and validated for damage and life prediction using DS GTD-111 as the subject material. This material, proprietary to General Electric Energy, has a chemical composition and grain structure designed to withstand creep damage occurring in the first and second stage blades of gas-powered turbines. The service conditions in these components, which generally exceed 600°C, facilitate the onset of one or more damage mechanisms related to fatigue, creep, or environment. The study was divided into an empirical phase, which consisted of experimentally simulating service conditions in fatigue specimens, and a modeling phase, which entailed numerically simulating the stress-strain response of the material. Experiments have been carried out to simulate a variety of thermal, mechanical, and environmental operating conditions endured by longitudinally (L) and transversely (T) oriented DS GTD-111. Both in-phase and out-of-phase thermo-mechanical fatigue tests were conducted. In some cases, tests in extreme environments/temperatures were needed to isolate one or at most two of the mechanisms causing damage. Microstructural examinations were carried out via SEM and optical microscopy. A continuum

  5. Microstructure and mechanical properties of a novel rapidly solidified, high-temperature Al-alloy

    Energy Technology Data Exchange (ETDEWEB)

    Overman, N.R., E-mail: Nicole.Overman@pnnl.gov [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (United States); Mathaudhu, S.N. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (United States); University of California, Riverside, 3401 Watkins Dr., Riverside, CA 92521 (United States); Choi, J.P.; Roosendaal, T.J.; Pitman, S. [Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (United States)

    2016-02-15

    Rapid solidification (RS) processing, as a production method, offers a variety of unique properties based on far-from-equilibrium microstructures obtained through rapid cooling rates. In this study, we seek to investigate the microstructures and properties of a novel Al-alloy specifically designed for high temperature mechanical stability. Synthesis of, AlFe{sub 11.4}Si{sub 1.8}V{sub 1.6}Mn{sub 0.9} (wt.%), was performed by two approaches: rotating cup atomization (“shot”) and melt spinning (“flake”). These methods were chosen because of their ability to produce alloys with tailored microstructures due to their inherent differences in cooling rate. The as-solidified precursor materials were microstructurally characterized with electron microscopy. The results show that the higher cooling rate flake material exhibited the formation of nanocrystalline regions as well additional phase morphologies not seen in the shot material. Secondary dendritic branching in the flake material was on the order of 0.1–0.25 μm whereas branching in the shot material was 0.5–1.0 μm. Consolidated and extruded material from both precursor materials was mechanically evaluated at both ambient and high (300 °C) temperature. The consolidated RS flake material is shown to exhibit higher strengths than the shot material. The ultimate tensile strength of the melt spun flake was reported as 544.2 MPa at room temperature and 298.0 MPa at 300 °C. These results forecast the ability to design alloys and processing approaches with unique non-equilibrium microstructures with robust mechanical properties at elevated temperatures. - Highlights: • A novel alloy, AlFe{sub 11.4}Si{sub 1.8}V{sub 1.6}Mn{sub 0.9} was fabricated by rapid solidification. • Room temperature yield strength exceeded 500 MPa. • Elevated temperature (300 °C) yield strength exceeded 275 MPa. • Forging, after extrusion of the alloy resulted in microstructural coarsening. • Decreased strength and ductility was

  6. Dendritic coarsening of γ' phase in a directionally solidified superalloy during 24,000 h of exposure at 1173 K

    International Nuclear Information System (INIS)

    Li, H.; Wang, L.; Lou, L.H.

    2010-01-01

    Dendritic coarsening of γ' was investigated in a directionally solidified Ni-base superalloy during exposure at 1173 K for 24,000 h. Chemical homogeneity along different directions and residual internal strain in the experimental superalloy were measured by electronic probe microanalysis (EPMA) and electron back-scattered diffraction (EBSD) technique. It was indicated that the gradient of element distribution was anisotropic and the inner strain between dendrite core and interdendritic regions was different even after 24,000 h of exposure at 1173 K, which influenced the kinetics for the dendrite coarsening of γ' phase.

  7. Deformation-induced structural changes of amorphous Ni{sub 0.5}Zr{sub 0.5} in molecular-dynamic simulations; Verformungsinduzierte Strukturaenderungen bei amorphen Ni{sub 0.5}Zr{sub 0.5} in Molekulardynamik-Simulationen

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, K

    2006-10-31

    The present work investigates the plastic deformation of metallic glasses by the aid of molecular-dynamic simulations. The parameters for the model system are adapted to those for a NiZr-alloy. In particular, the composition Ni{sub 0.5}Zr{sub 0.5} is used. The analyzed deformation simulations are conducted for small systems with 5184 atoms and large systems with 17500 atoms in a periodic simulation cell. The deformation simulations of pre-deformed samples are carried out either at constant shear-rate or at constant load, the latter mode modeling a creep experiment. Stress-strain curves for pre-deformed samples show a less pronounced stress-overshoot phenomenon. Creep-simulations of samples deformed beyond the yield region indicate a drastically reduced viscosity in these systems when compared to samples pre-deformed only up to the linear regime of the stress-strain curve. From analyzing the local atomic topology it is found that the transition from the highly viscous, hard-to-deform state of the undeformed or only weakly strained system into the easy-to-deform flow-state, present if the system is strained far beyond the yielding regime of the stress-strain curve, is connected with the formation of a region containing atoms with massive changes in their topology which is oriented along a diagonal plane of the simulation cell. The degree of localization of these deformation bands is influenced by temperature and shear-rate. In subsequent deformations of pre-deformed samples the regions with massive changes in the atomic topology are again susceptible to changes in the local atomic topology. By using methods from statistics, a significant difference in the distribution of atomic properties for the group of atoms with massive topology changes on the one hand and the group of atoms without changes in their topology on the other gets quantitatively ascertainable. From the differences in structural properties, e.g. potential energy, cage volumes, angular order parameters

  8. In vitro corrosion and biocompatibility screening of sputtered Ti{sub 40}Cu{sub 36}Pd{sub 14}Zr{sub 10} thin film metallic glasses on steels

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, B., E-mail: subramanianb3@gmail.com

    2015-02-01

    The growth of multi-component thin film metallic glasses (TFMGs) of Ti{sub 40}Cu{sub 36}Pd{sub 14}Zr{sub 10} (at.%) alloys fabricated using magnetron sputtering on bioimplantable 316L stainless steel substrates has been investigated. The vapor–solid quenching during sputtering enables the amorphous phases to be formed. The amorphous films consist of a single glassy phase, as evidenced by a broad hump and no detectable crystalline peaks as observed from XRD and selective area electron diffraction (SAED) patterns. The average surface roughness (Ra) of the coated film as observed from AFM was 0.3 nm. Nanohardness of about 7.7 GPa and Young's modulus of 110 GPa were measured from nanoindentation analysis. The potentiodynamic polarization and impedance measurements showed that coated stainless steel substrates have higher corrosion resistance compared to uncoated SS substrate in simulated body fluid (SBF) solution. The cytotoxicity studies using L929 fibroblast cells showed that these coatings were non-cytotoxic in nature. The interactions between the coated surface and bacteria were investigated by agar diffusion method, solution suspension and wet interfacial contact methods. - Highlights: • Ti-based TFMG coated specimen showed superior corrosion resistance. • Ti-based TFMG coated SS 316L specimen was non-cytotoxic in nature. • Antimicrobial activity of Ti-based TFMG was noticed.

  9. Thermal cycling behavior of La{sub 2}Zr{sub 2}O{sub 7} coating with the addition of Y{sub 2}O{sub 3} by EB-PVD

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhenhua [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); He Limin, E-mail: he_limin@yahoo.co [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Chen Xiaolong; Zhao Yu [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Mu Rende; He Shimei [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao Xueqiang, E-mail: xcao@ciac.jl.c [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2010-10-15

    Thermal barrier coatings (TBCs) of La{sub 2}Zr{sub 2}O{sub 7} (LZ) with the addition of 3 wt.% Y{sub 2}O{sub 3} (LZ3Y) were deposited by electron beam-physical vapor deposition (EB-PVD). The phase structures, surface and cross-sectional morphologies, cyclic oxidation behaviors of these coatings were studied in detail. The thermal cycling test at 1373 K in an air furnace indicates that the LZ3Y coating has a lifetime of 617 cycles which is about 10% longer than that of LZ coating. The improvement of chemical homogeneity of the coating, the superior growth behavior of columns and the favorable mechanical properties are all very helpful to the prolongation of thermal cycling life of LZ3Y coating. The failure of LZ and LZ3Y coatings is mainly a result of the excess La{sub 2}O{sub 3}, the chemical incompatibility of ceramic coatings with TGO layer, the thermal expansion mismatch between ceramic coatings and bond coat, and the outward diffusion of alloying elements into the ceramic coatings.

  10. Atomic structure of Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} bulk metallic glass alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hui, X. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail: huixd01@hotmail.com; Fang, H.Z.; Chen, G.L. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shang, S.L.; Wang, Y. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Qin, J.Y. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University - Southern Campus, Jinan 250061 (China); Liu, Z.K. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2009-01-15

    Ab initio molecular dynamics (AIMD) calculations were performed on the atomic configuration of Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} bulk metallic glass. The local structures were characterized in terms of structure factors (SF), pair correlation functions (PCF), coordinate numbers, bond pairs and Voronoi polyhedra. The glass transition temperature, generalized PCF and SF predicated by AIMD are in good agreement with the experimental data. Icosahedral short-range orders (ISRO) are found to be the most dominant, in view of the presence of the majority of bond pairs with 1551, 1541 and 1431, and Voronoi polyhedra with <0,3,6,1>, <0,2,8,1>, <0,0,12,0> and <0,2,8,4>. Icosahedral medium range orders (IMROs) are formed from icosahedra via the linkage of vertex-, edge-, face- and intercross-shared atoms. The glass structure on the nanometer scale is accumulated by polyhedra through an efficient packing mode. It is suggested that the extraordinary glass-forming ability of this alloy is essentially attributable to the formation of ISRO and IMRO, and the dense packing of atoms.

  11. Anisotropic bonded Sm{sub 2.3}Fe{sub 16.8}Zr{sub 0.2}N{sub y} magnets prepared by milling of as cast material

    Energy Technology Data Exchange (ETDEWEB)

    Gebel, B.; Kubis, M.; Roessler, U.K.; Mueller, K.H. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany). Inst. fuer Metallische Werkstoffe

    2001-07-01

    As cast Sm{sub 2.3}Fe{sub 16.8}Zr{sub 0.2} material was milled for 100 min {<=} t {<=} 900 min. After annealing at 800 C for 1 h and subsequent nitrogenation, the samples were cold compacted in a magnetic field and resin bonded. The coercivity {mu}{sub 0J}H{sub C} of the samples increased from 0.59 T (t = 100 min) to 2.18 T (t = 900 min). On the other hand, the remanence along the texture axis decreased monotonically with increasing milling time due to the decrease of the degree of texture of the aligned powders. Prolonged milling leads finally to the formation of a soft magnetic phase as indicated by a shoulder in the demagnetization curve for t > 600 min. The highest energy product (BH){sub max} of 50 kJm{sup -3} (136 kJm{sup -3} for the theoretical density of 7.7 gcm{sup -3}) was obtained for an intermediate milling time of 400 min. Zn bonding of the powders resulted in magnets with lower energy products but improved coercivities. (orig.)

  12. Paramagnetic susceptibility of the Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} metallic glass subjected to high-pressure torsion deformation

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, A.V., E-mail: korolyov@imp.uran.ru [Institute of Metal Physics of the Ural Branch RAS, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation); Kourov, N.I. [Institute of Metal Physics of the Ural Branch RAS, Ekaterinburg (Russian Federation); Pushin, V.G. [Institute of Metal Physics of the Ural Branch RAS, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation); Gunderov, D.V. [Saint-Petersburg State University, Saint-Petersburg (Russian Federation); Ufa State Aviation Technical University, Ufa (Russian Federation); Boltynjuk, E.V.; Ubyivovk, E.V. [Saint-Petersburg State University, Saint-Petersburg (Russian Federation); Valiev, R.Z. [Saint-Petersburg State University, Saint-Petersburg (Russian Federation); Ufa State Aviation Technical University, Ufa (Russian Federation)

    2017-09-01

    Highlights: • Zr-based BMG was subjected to HPT at temperatures of 20 °C and 150 °C. • Magnetic measurements reveal well recordable changes in paramagnetic susceptibility. • Paramagnetic susceptibility may be an indicator of a change in the structural state. - Abstract: The Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} bulk metallic glass is studied in the as-cast state and in the state after processing by high-pressure torsion at temperatures of 20 °C and 150 °C. According to the data from X-ray diffraction and transmission electron microscopy, the structural state of the samples depends weakly on the conducted processing. At the same time, magnetic measurements reveal well recordable changes in paramagnetic susceptibility induced by the processing of the samples. It is assumed that, because of high-pressure torsion deformation, there occurs a noticeable change in the material electronic structure, which leads to a change in the full susceptibility of the samples. The performed studies demonstrate that paramagnetic susceptibility may be an indicator of a change in the structural state of paramagnetic amorphous metallic substances.

  13. Temperature dependence of the minimum in AC power losses of (Nb/sub 0.99/Zr/sub 0.01/)3Sn in parallel AC and DC magnetic fields

    International Nuclear Information System (INIS)

    Kovachev, V.T.

    1980-01-01

    ac losses P/sub L/ of bronze-processed (Nb/sub 0.99/Zr/sub 0.01/) 3 Sn strips have been measured between 4.2 and 16.5 K in the presence of a dc magnetic field H 0 . The measurements were performed using an electronic wattmeter with both ac and dc fields parallel to the long flat surfaces of the sample. A minimum in the function P/sub L/(H 0 ) was observed for fixed ac amplitudes h 0 . This minimum was found to occur in the entire temperature range between 4.2 and 16.5 K. A similar minimum was recently reported in Nb 3 Ge [Thompson et al., J. Appl. Phys. 50, 3514 (1979)] at 4.2 K. The position of the minimum is explained here by the same physical model as in Thompson et al. [J. Appl. Phys. 50, 3514 (1979)]; and Clem (ibid. 3518), but extending the model to include the temperature dependence of the entry surface shielding fields ΔH/sub en/(B,T) for flux density in the sample B=0. It is also shown here that loss minimum measurements can be used for the determination of ΔH/sub en/(0,T) in the temperature range 4.2--16.5 K

  14. Structural analysis, optical and dielectric function of [Ba{sub 0.9}Ca{sub 0.1}](Ti{sub 0.9}Zr{sub 0.1})O{sub 3} nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Pérez, G., E-mail: guillermo.herrera@cimav.edu.mx, E-mail: damasio.morales@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), S. C. Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Physics of Materials Department, Centro de Investigación en Materiales Avanzados (CIMAV), S. C. Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Morales, D., E-mail: guillermo.herrera@cimav.edu.mx, E-mail: damasio.morales@cimav.edu.mx; Paraguay-Delgado, F.; Reyes-Rojas, A.; Fuentes-Cobas, L. E. [Physics of Materials Department, Centro de Investigación en Materiales Avanzados (CIMAV), S. C. Miguel de Cervantes 120, Chihuahua 31136, Chihuahua (Mexico); Borja-Urby, R. [Centro de Nanociencias Micro y Nanotecnologías, Instituto Politécnico Nacional, 07300 México City (Mexico)

    2016-09-07

    This work presents the identification of inter-band transitions in the imaginary part of the dielectric function (ε{sub 2}) derived from the Kramers–Kronig analysis for [Ba{sub 0.9}Ca{sub 0.1}](Ti{sub 0.9}Zr{sub 0.1})O{sub 3} (BCZT) nanocrystals synthesized by the modified Pechini method. The analysis started with the chemical identification of the atoms that conform BCZT in the valence loss energy region of a high energy-resolution of electron energy loss spectroscopy. The indirect band energy (E{sub g}) was determined in the dielectric response function. This result is in agreement with the UV-Vis technique, and it obtained an optical band gap of 3.16 eV. The surface and volume plasmon peaks were observed at 13.1 eV and 26.2 eV, respectively. The X-ray diffraction pattern and the Rietveld refinement data of powders heat treated at 700 °C for 1 h suggest a tetragonal structure with a space group (P4 mm) with the average crystal size of 35 nm. The average particle size was determined by transmission electron microscopy.

  15. Studies of the Influence of Beam Profile and Cooling Conditions on the Laser Deposition of a Directionally-Solidified Superalloy

    Directory of Open Access Journals (Sweden)

    Shuo Yang

    2018-02-01

    Full Text Available In the laser deposition of single crystal and directionally-solidified superalloys, it is desired to form laser deposits with high volume fractions of columnar grains by suppressing the columnar-to-equiaxed transition efficiently. In this paper, the influence of beam profile (circular and square shapes and cooling conditions (natural cooling and forced cooling on the geometric morphology and microstructure of deposits were experimentally studied in the laser deposition of a directionally-solidified superalloy, IC10, and the mechanisms of influence were revealed through a numerical simulation of the thermal processes during laser deposition. The results show that wider and thinner deposits were obtained with the square laser beam than those with the circular laser beam, regardless of whether natural or forced cooling conditions was used. The heights and contact angles of deposits were notably increased due to the reduced substrate temperatures by the application of forced cooling for both laser beam profiles. Under natural cooling conditions, columnar grains formed epitaxially at both the center and the edges of the deposits with the square laser beam, but only at the center of the deposits with the circular laser beam; under forced cooling conditions, columnar grains formed at both the center and the edges of deposits regardless of the laser beam profile. The high ratios of thermal gradient and solidification velocity in the height direction of the deposits were favorable to forming deposits with higher volume fractions of columnar grains.

  16. Printing low-melting-point alloy ink to directly make a solidified circuit or functional device with a heating pen.

    Science.gov (United States)

    Wang, Lei; Liu, Jing

    2014-12-08

    A new method to directly print out a solidified electronic circuit through low-melting-point metal ink is proposed. A functional pen with heating capability was fabricated. Several typical thermal properties of the alloy ink Bi 35 In 48.6 Sn 16 Zn 0.4 were measured and evaluated. Owing to the specifically selected melting point of the ink, which is slightly higher than room temperature, various electronic devices, graphics or circuits can be manufactured in a short period of time and then rapidly solidified by cooling in the surrounding air. The liquid-solid phase change mechanism of the written lines was experimentally characterized using a scanning electron microscope. In order to determine the matching substrate, wettability between the metal ink Bi 35 In 48.6 Sn 16 Zn 0.4 and several materials, including mica plate and silicone rubber, was investigated. The resistance-temperature curve of a printed resistor indicated its potential as a temperature control switch. Furthermore, the measured reflection coefficient of a printed double-diamond antenna accords well with the simulated result. With unique merits such as no pollution, no requirement for encapsulation and easy recycling, the present printing approach is an important supplement to current printed electronics and has enormous practical value in the future.

  17. Effect of solidification parameters on mechanical properties of directionally solidified Al-Rich Al-Cu alloys

    Science.gov (United States)

    Çadırlı, Emin

    2013-05-01

    Al(100-x)-Cux alloys (x=3 wt%, 6 wt%, 15 wt%, 24 wt% and 33 wt%) were prepared using metals of 99.99% high purity in vacuum atmosphere. These alloys were directionally solidified under steady-state conditions by using a Bridgman-type directional solidification furnace. Solidification parameters (G, V and ), microstructure parameters (λ1, λ2 and λE) and mechanical properties (HV, σ) of the Al-Cu alloys were measured. Microstructure parameters were expressed as functions of solidification parameters by using a linear regression analysis. The dependency of HV, σ on the cooling rate, microstructure parameters and composition were determined. According to experimental results, the microhardness and ultimate tensile strength of the solidified samples was increased by increasing the cooling rate and Cu content, but decreased with increasing microstructure parameters. The microscopic fracture surfaces of the different samples were observed using scanning electron microscopy. Fractographic analysis of the tensile fracture surfaces showed that the type of fracture significantly changed from ductile to brittle depending on the composition.

  18. Cold Heat Release Characteristics of Solidified Oil Droplet-Water Solution Latent Heat Emulsion by Air Bubbles

    Science.gov (United States)

    Inaba, Hideo; Morita, Shin-Ichi

    The present work investigates the cold heat-release characteristics of the solidified oil droplets (tetradecane, C14H30, freezing point 278.9 K)/water solution emulsion as a latent heat-storage material having a low melting point. An air bubbles-emulsion direct-contact heat exchange method is selected for the cold heat-results from the solidified oil droplet-emulsion layer. This type of direct-contact method results in the high thermal efficiency. The diameter of air bubbles in the emulsion increases as compared with that in the pure water. The air bubbles blown from a nozzle show a strong mixing behavior during rising in the emulsion. The temperature effectiveness, the sensible heat release time and the latent heat release time have been measured as experimental parameters. The useful nondimensional emulsion level equations for these parameters have been derived in terms of the nondimensional emalsion level expressed the emulsion layer dimensions, Reynolds number for air flow, Stefan number and heat capacity ratio.

  19. Leach studies on cement-solidified ion exchange resins from decontamination processes at operating nuclear power stations

    International Nuclear Information System (INIS)

    McIsaac, C.V.; Akers, D.W.; McConnell, J.W.; Morcos, N.

    1992-01-01

    The effects of varying pH and leachant compositions on the physical stability and leachability of radionuclides and chelating agents were determined for cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small scale waste-form specimens were collected during waste solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station. The collected specimens were leach tested, and their compressive strength was measured in accordance with the Nuclear Regulatory Commission's ''Technical Position on Waste Form'' (Revision 1), from the Low-Level Waste Management Branch. Leachates from these studies were analyzed for radionuclides, selected transition metals, and chelating agents to assess the leachability of these waste form constituents. Leachants used for the study were deionized water, simulated seawater, and groundwater compositions similar to those found at Barnwell, South Carolina and Hanford, Washington. Results of this study indicate that initial leachant pH does not affect leachate pH or releases from cement-solidified decontamination ion-exchange resin waste forms. However, differences in leachant composition and the presence of chelating agents may affect the releases of radionuclides and chelating agents. In addition, results from this study indicate that the cumulative releases of radionuclides and chelating agents observed for forms that disintegrated were similar to those for forms that maintained their general physical integrity

  20. Nial and Nial-Based Composites Directionally Solidified by a Containerless Zone Process. Ph.D. Thesis

    Science.gov (United States)

    Joslin, Steven M.

    1995-01-01

    A containerless electromagnetically levitated zone (CELZ) process has been used to directionally solidify NiAl and NiAl-based composites. The CELZ processing results in single crystal NiAl (HP-NiAl) having higher purity than commercially pure NiAl grown by a modified Bridgman process (CP-NiAl). The mechanical properties, specifically fracture toughness and creep strength, of the HP-NiAl are superior to binary CP-NiAl and are used as a base-line for comparison with the composite materials subsequently studied. Two-phase composite materials (NiAl-based eutectic alloys) show improvement in room temperature fracture toughness and 1200 to 1400 K creep strength over that of binary HP-NiAl. Metallic phase reinforcements produce the greatest improvement in fracture toughness, while intermetallic reinforcement produces the largest improvement in high temperature strength. Three-phase eutectic alloys and composite materials were identified and directionally solidified with the intent to combine the improvements observed in the two-phase alloys into one alloy. The room temperature fracture toughness and high temperature strength (in air) serve as the basis for comparison between all of the alloys. Finally, the composite materials are discussed in terms of dominant fracture mechanism observed by fractography.

  1. Influence of carbonation on the acid neutralization capacity of cements and cement-solidified/stabilized electroplating sludge.

    Science.gov (United States)

    Chen, Quanyuan; Zhang, Lina; Ke, Yujuan; Hills, Colin; Kang, Yanming

    2009-02-01

    Portland cement (PC) and blended cements containing pulverized fuel ash (PFA) or granulated blast-furnace slag (GGBS) were used to solidify/stabilize an electroplating sludge in this work. The acid neutralization capacity (ANC) of the hydrated pastes increased in the order of PC > PC/GGBS > PC/PFA. The GGBS or PFA replacement (80 wt%) reduced the ANC of the hydrated pastes by 30-50%. The ANC of the blended cement-solidified electroplating sludge (cement/sludge 1:2) was 20-30% higher than that of the hydrated blended cement pastes. Upon carbonation, there was little difference in the ANC of the three cement pastes, but the presence of electroplating sludge (cement/sludge 1:2) increased the ANC by 20%. Blended cements were more effective binders for immobilization of Ni, Cr and Cu, compared with PC, whereas Zn was encapsulated more effectively in the latter. Accelerated carbonation improved the immobilization of Cr, Cu and Zn, but not Ni. The geochemical code PHREEQC, with the edited database from EQ3/6 and HATCHES, was used to calculate the saturation index and solubility of likely heavy metal precipitates in cement-based solidification/stabilization systems. The release of heavy metals could be related to the disruption of cement matrices and the remarkable variation of solubility of heavy metal precipitates at different pH values.

  2. Setting of cesium residual ratio of molten solidified waste produced in Japan Atomic Power Company Tokai and Tokai No.2 Power Stations

    International Nuclear Information System (INIS)

    2013-02-01

    JNES investigated the appropriateness of a view of the Japan Nuclear Fuel Co. on cesium residual content and the radioactivity measurement precision regarding the molten solidified (with lowered inorganic salt used) radioactive wastes which were produced from Japan Atomic Power Company Tokai and Tokai No. 2 Power Stations. Based on the written performance report from the request and past disposal confirmation experience, a view of the JNFC is confirmed as appropriate that setting of 15% cesium residual ratio for molten solidified with volume ratio larger than 4% and less than 10% cases. (S. Ohno)

  3. A coupled analysis of fluid flow, heat transfer and deformation behavior of solidifying shell in continuously cast beam blank

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Eui; Yeo, Tae Jung; Oh, Kyu Hwan; Yoon, Jong Kyu [School of Materials Science and Engineering, Seoul Nat` l Univ., Seoul (Korea, Republic of); Han, Heung Nam [Oxford Center for Advanced Materials and Composites, Department of Materials, Univ. of Oxford (United Kingdom)

    1998-12-31

    A mathematical model for a coupled analysis of fluid flow, heat transfer and deformation behavior in the continuously cast beam blank has been developed. The fluid flow, heat transfer and solidification in the mold region were analyzed with 3-dimensional finite difference method (FDM) based on control volume method. A body fitted coordinate system was introduced for the complex geometry of the beam blank. The effects of turbulence and natural convection of molten steel were taken into account in determining the fluid flow in the strand. The thermo-elasto-plastic deformation behavior in the cast strand and the formation of air gap between the solidifying shell and the mold were analyzed by the finite element method (FEM) using the 2-dimensional slice temperature profile calculated by the FDM. The heat flow between the strand and the mold was evaluated by the coupled analysis between the fluid flow-heat transfer analysis and the thermo-elasto-plastic stress analysis. In order to determine the solid fraction in the mushy zone, the microsegregation of solute element was assessed. The effects of fluid flow on the heat transfer, the solidification of steel and the distribution of shell thickness during the casting of the beam blank were simulated. The deformation behavior of the solidifying shell and the possibility of cracking of the strand were also investigated. The recirculating flows were developed in the regions of the web and the flange tip. The impinging of the inlet flow from the nozzle retarded the growing of solidifying shell in the regions of the fillet and the flange. The air gap between the strand and the mold was formed near the region of the corner of the flange tip. At the initial stage of casting, the probability of the surface cracking was high in the regions of the fillet and the flange tip. After the middle stage of casting, the internal cracking was predicted in the regions of the flange tip, and between the fillet and the flange tip. (author) 38

  4. A coupled analysis of fluid flow, heat transfer and deformation behavior of solidifying shell in continuously cast beam blank

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Eui; Yeo, Tae Jung; Oh, Kyu Hwan; Yoon, Jong Kyu [School of Materials Science and Engineering, Seoul Nat`l Univ., Seoul (Korea, Republic of); Han, Heung Nam [Oxford Center for Advanced Materials and Composites, Department of Materials, Univ. of Oxford (United Kingdom)

    1997-12-31

    A mathematical model for a coupled analysis of fluid flow, heat transfer and deformation behavior in the continuously cast beam blank has been developed. The fluid flow, heat transfer and solidification in the mold region were analyzed with 3-dimensional finite difference method (FDM) based on control volume method. A body fitted coordinate system was introduced for the complex geometry of the beam blank. The effects of turbulence and natural convection of molten steel were taken into account in determining the fluid flow in the strand. The thermo-elasto-plastic deformation behavior in the cast strand and the formation of air gap between the solidifying shell and the mold were analyzed by the finite element method (FEM) using the 2-dimensional slice temperature profile calculated by the FDM. The heat flow between the strand and the mold was evaluated by the coupled analysis between the fluid flow-heat transfer analysis and the thermo-elasto-plastic stress analysis. In order to determine the solid fraction in the mushy zone, the microsegregation of solute element was assessed. The effects of fluid flow on the heat transfer, the solidification of steel and the distribution of shell thickness during the casting of the beam blank were simulated. The deformation behavior of the solidifying shell and the possibility of cracking of the strand were also investigated. The recirculating flows were developed in the regions of the web and the flange tip. The impinging of the inlet flow from the nozzle retarded the growing of solidifying shell in the regions of the fillet and the flange. The air gap between the strand and the mold was formed near the region of the corner of the flange tip. At the initial stage of casting, the probability of the surface cracking was high in the regions of the fillet and the flange tip. After the middle stage of casting, the internal cracking was predicted in the regions of the flange tip, and between the fillet and the flange tip. (author) 38

  5. Temperature effect on uranium retention onto Zr{sub 2}O(PO{sub 4}){sub 2} surface; Effet de la temperature sur les mecanismes d'interaction entre l'ion uranyle et l'oxophosphate de zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Almazan Torres, M.G

    2007-03-15

    Uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} has been studied between 298 K and 363 K, in 0.1 M NaClO{sub 4} medium. Potentiometric titrations were realized to determine temperature dependency of the acid-base properties (pH(pcn), acidity constants). Classical batch experiments were performed at different temperatures. The sorption experiments revealed that the uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} is favoured with the temperature. Structural characterization of the surface complexes was performed by both Time-Resolved Laser-Induced Fluorescence (TRLIF) and EXAFS spectroscopy. The TRLIF measurements vs. temperature revealed two uranyl surface complexes. No influence of the temperature onto the nature surface complex was observed. The EXAFS analysis showed a splitting of the equatorial oxygen atoms in two shells, corresponding to uranyl bidentate, inner-sphere complexes. The obtained structural uranyl surface complex information was used to simulate (using a constant capacitance model) the sorption edges. The proposed complexes equilibrium model consists of the following surface complexes: (ZrOH){sub 2}UO{sub 2}{sup 2+} and (PO){sub 2}UO{sub 2}. Besides the stability constants for the surface complexes, the thermodynamic parameters {delta}H{sup 0} and {delta}S{sup 0} were determined using the van't Hoff equation. The enthalpy values associated to the U(VI) retention onto Zr{sub 2}O(PO{sub 4}){sub 2}, determined by the temperature dependence of the stability constants, testify that the formation of the complex (PO){sub 2}UO{sub 2} (55 kJ/mol) is endothermic, while no influence of the temperature was observed for the formation of the complex (ZrOH){sub 2}UO{sub 2}{sup 2+}. The adsorption reaction of the last complex is then driven by entropy. In addition, calorimetric measurements of uranium sorption onto Zr{sub 2}O(PO{sub 4}){sub 2} were carried out to directly quantify the enthalpy associated to the retention processes. (author)

  6. Prediction of as-cast grain size of inoculated aluminum alloys melt solidified under non-isothermal conditions

    International Nuclear Information System (INIS)

    Du, Qiang; Li, Yanjun

    2015-01-01

    In this paper, a multi-scale as-cast grain size prediction model is proposed to predict as-cast grain size of inoculated aluminum alloys melt solidified under non-isothermal condition, i.e., the existence of temperature gradient. Given melt composition, inoculation and heat extraction boundary conditions, the model is able to predict maximum nucleation undercooling, cooling curve, primary phase solidification path and final as-cast grain size of binary alloys. The proposed model has been applied to two Al-Mg alloys, and comparison with laboratory and industrial solidification experimental results have been carried out. The preliminary conclusion is that the proposed model is a promising suitable microscopic model used within the multi-scale casting simulation modelling framework. (paper)

  7. Morphological variants of carbides of solidification origin in the rapidly solidified powder particles of hypereutectic iron alloy

    International Nuclear Information System (INIS)

    Kusy, M.; Grgac, P.; Behulova, M.; Vyrostkova, A.; Miglierini, M.

    2004-01-01

    The paper deals with the analysis of the morphological variants of solidification microstructures and vanadium rich M 4 C 3 carbide phases in the rapidly solidified (RS) powder particles from hypereutectic Fe-C-Cr-V alloy prepared by the nitrogen gas atomisation. Five main types of solidification microstructures were identified in RS particles: microstructure with globular carbides, microstructure with globular and star-like carbides, microstructure with primary carbides in the centres of eutectic colonies, microstructure with eutectic colonies without primary carbides and microstructure with eutectic spherulites. Based on the morphological features of carbide phases and the thermal history of RS particles, the microstructures were divided into two groups - microstructures morphologically affected and non-affected during the post-recalescence period of solidification. Thermophysical reasons for the morphologically different M 4 C 3 carbide phases development in the RS powder particles are discussed

  8. Effect of thermal cycling on the microstructure of a directionally solidified Fe, Cr, Al-TaC eutectic alloy

    Science.gov (United States)

    Harf, F. H.; Tewari, S. N.

    1977-01-01

    Cylindrical bars (1.2 cm diameter) of Fe-13.6Cr-3.7Al-9TaC (wt %) eutectic alloy were directionally solidified in a modified Bridgman type furnace at 1 cm/h. The alloy microstructure consisted of aligned TaC fibers imbedded in a bcc Fe-Cr-Al matrix. Specimens of the alloy were thermally cycled from 1100 to 425 C in a burner rig. The effects of 1800 thermal cycles on the microstructure was examined by scanning electron microscopy, revealing a zig-zag shape of TaC fibers aligned parallel to the growth direction. The mechanism of carbide solution and reprecipitation on the (111) easy growth planes, suggested previously to account for the development of irregular serrations in Co-Cr-Ni matrix alloys, is believed to be responsible for these zig-zag surfaces.

  9. Effect of processing on the microstructural development in a rapidly solidified Al-Fe-V-Si alloy

    International Nuclear Information System (INIS)

    Srivastava, A.K.; Ranganathan, S.; Ojha, S.N.

    1993-01-01

    An Al 80 Fe 10 Si 6 alloy has been rapidly solidified using melt spinning, gas atomization and spray forming processes. The effect of processing techniques on the microstructural characteristics of the alloy has ben evaluated. The melt spun alloy has shown an icosahedral quasicrystalline phase surrounded by a rational approximant structure of the icosahedral phase. The rational approximant structure has been identified as a crystalline cubic silicide phase. The atomized powders have exhibited cellular and dendritic morphology depending on the size of particles. In addition, the second phase particles of the silicide phase are observed to decorate the cell boundaries and interdendritic regions. In contrast, the alloy processed by spray deposition has revealed an equiaxed solidification morphology with a uniform dispersion of find silicon phase inside the grain. The origin of the microstructure in the alloy processed by these techniques is discussed. The results are compared wherever possible with the commercially available Al-Fe-V-Si alloys

  10. Tensile behavior change depending on the microstructure of a Fe-Cu alloy produced from rapidly solidified powder

    International Nuclear Information System (INIS)

    Kakisawa, Hideki; Minagawa, Kazumi; Halada, Kohmei

    2003-01-01

    The relationship between consolidating temperature and the tensile behavior of iron alloy produced from Fe-Cu rapidly solidified powder is investigated. Fe-Cu powder fabricated by high-pressure water atomization was consolidated by heavy rolling at 873-1273 K. Microstructural changes were observed and tensile behavior was examined. Tensile behavior varies as the consolidating temperature changes, and these temperature-dependent differences depend on the morphology of the microstructure on the order of micrometers. The sample consolidated at 873 K shows a good strength/elongation balance because the powder microstructure and primary powder boundaries are maintained. The samples consolidated at the higher temperatures have a microstructure of recrystallized grains, and these recrystallized samples show the conventional relationship between tensile behavior and grain size in ordinal bulk materials

  11. Hydration products and mechanical properties of hydroceramics solidified waste for simulated Non-alpha low and intermediate level radioactive wastes

    International Nuclear Information System (INIS)

    Wang Jin; Hong Ming; Wang Junxia; Li Yuxiang; Teng Yuancheng; Wu Xiuling

    2011-01-01

    In this paper, simulated non-alpha low and intermediate level radioactive wastes was handled as curing object and that of 'alkali-slag-coal fly ash-metakaolin' hydroceramics waste forms were prepared by hydrothermal synthesis method. The hydration products were analyzed by X ray diffraction. The composition of hydrates and the compressive strength of waste forms were determined and measured. The results indicate that the main crystalline phase of hydration products were analcite when the temperature was 150 to 180 degree C and the salt content ratio was 0.10 to 0.30. Analcite diffraction peaks in hydration products is increasing when the temperature was raised and the reaction time prolonged. Strength test results show that the solidified waste forms have superior compressive strength. The compressive strength gradually decreased with the increase in salt content ratio in waste forms. (authors)

  12. Characterization of solidified radioactive wastes produced at Montalto di Castro BWR plant with reference to the site storage

    International Nuclear Information System (INIS)

    Donato, A.; Ricci, G.; Pace, A.

    1985-01-01

    The cement solidification of the Montalto di Castro BWR plant radwastes has been studied both from the point of view of the mixtures of formulation and of the product characterization. Five radwaste types and mixtures of them have been taken into consideration, determining the best chemical formulations starting from the compressive strenght as leading parameter. The solidified products have been characterized from the point of view of the freeze and thawing resistance, the water immersion resistance, the leachability, the dimensional changes and the free standing water. All the tests have been performed taking into account the real site conditions, so the leaching tests and the water immersion tests have been carried out using sea water and table water as leachant

  13. Shipment and Disposal of Solidified Organic Waste (Waste Type IV) to the Waste Isolation Pilot Plant (WIPP)

    International Nuclear Information System (INIS)

    D'Amico, E. L; Edmiston, D. R.; O'Leary, G. A.; Rivera, M. A.; Steward, D. M.

    2006-01-01

    In April of 2005, the last shipment of transuranic (TRU) waste from the Rocky Flats Environmental Technology Site to the WIPP was completed. With the completion of this shipment, all transuranic waste generated and stored at Rocky Flats was successfully removed from the site and shipped to and disposed of at the WIPP. Some of the last waste to be shipped and disposed of at the WIPP was waste consisting of solidified organic liquids that is identified as Waste Type IV in the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC) document. Waste Type IV waste typically has a composition, and associated characteristics, that make it significantly more difficult to ship and dispose of than other Waste Types, especially with respect to gas generation. This paper provides an overview of the experience gained at Rocky Flats for management, transportation and disposal of Type IV waste at WIPP, particularly with respect to gas generation testing. (authors)

  14. Segregation and microstructure evolution in chill cast and directionally solidified Ni-Mn-Sn metamagnetic shape memory alloys

    Science.gov (United States)

    Czaja, P.; Wierzbicka-Miernik, A.; Rogal, Ł.

    2018-06-01

    A multiphase solidification behaviour is confirmed for a range of Ni-rich and Ni-deficient Ni-Mn-Sn induction cast and directionally solidified (Bridgman) alloys. The composition variation is primarily linked to the changing Mn/Sn ratio, whereas the content of Ni remains largely stable. The partitioning coefficients for the Ni50Mn37Sn13 and Ni46Mn41.5Sn12.5 Bridgman alloys were obtained according to the Scheil equation based on the composition distribution along the longitudinal cross section of the ingots. Homogenization heat treatment performed for 72 h at 1220 K turned out sufficient for ensuring chemical uniformity on the macro- and microscale. It is owed to a limited segregation length scale due to slow cooling rates adopted for the directional solidification process.

  15. Nd{sup 3+}-substituted (Zr{sub 1−x}Ce{sub x})O{sub 2} (0.0 ≤ x ≤ 1.0) system: Synthesis, structural and thermophysical investigations

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Chiranjit [Radiometallurgy Division, Bhabha Atomic Research Centre, HBNI, Mumbai 400085 (India); Grover, V., E-mail: Vinita@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, HBNI, Mumbai 400085 (India); Sahu, M. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Krishnan, K. [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Guleria, A. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaity, Santu; Prakash, Amrit [Radiometallurgy Division, Bhabha Atomic Research Centre, HBNI, Mumbai 400085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, HBNI, Mumbai 400085 (India)

    2016-10-15

    In order to mimic co-loading of Pu and Am in zirconia, Nd{sub 0.20}[Zr{sub 1−x}Ce{sub x}]{sub 0.80}O{sub 1.90} (0.0 ≤ x ≤ 1.0) system was synthesized and thoroughly characterized by X-ray diffraction (XRD) and Raman spectroscopy. The entire system was found to be single-phasic fluorite-type and most interesting result is stabilization of multi-phasic ceria-zirconia system in a single-phasic system by substituting Nd{sup 3+}. Raman spectroscopy revealed entirely different nature of defects prevalent in the solid solutions possessing F-type structure across the composition range. The heat capacity of representative compositions was measured by heat flux-type differential scanning calorimeter. Specific heat capacity of the solid solutions was found to increase with decreasing CeO{sub 2} content. Different thermodynamic functions such as enthalpy increment, entropy and Gibbs energy functions were determined using heat capacity values. The lattice thermal expansion (298–1273 K) behaviour of the few selected compositions revealed a gradual increase in thermal expansion coefficient with increasing CeO{sub 2} content. - Highlights: • Single-phasic fluorite-type solid solution obtained across the composition range. • Multi-phasic CeO{sub 2}-ZrO{sub 2} system converted into single-phasic by Nd{sup 3+} substitution. • Different local structures and defects in Ce-rich and Zr-rich regions. • Lattice thermal expansion coefficient increases with increasing CeO{sub 2} content. • Thermal expansion behaviour is a manifestation of decreasing melting point.

  16. Photoluminescence in Pb{sub 0.95}Sr{sub 0.05}(Zr{sub 1−x}Ti{sub x}){sub 1−y}Cr{sub y}O{sub 3} ferroelectric ceramic system

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-García, M.; Costa-Marrero, J. [Departamento de Física Aplicada, Instituto de Cibernética, Matemática y Física, 15 # 551, Vedado, Ciudad Habana, CP 10400 (Cuba); Durruthy-Rodríguez, M. D., E-mail: dolores@icmf.inf.cu [Departamento de Física Aplicada, Instituto de Cibernética, Matemática y Física, 15 # 551, Vedado, Ciudad Habana, CP 10400 (Cuba); CINVESTAV-Unidad Querétaro, IPN, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, CP. 76230 Querétaro, Querétaro (Mexico); Calderón-Piñar, F. [Laboratorio de Magnetismo, Instituto de Ciencia y Tecnología de Materiales, Universidad de La Habana, La Habana, CP 10400 (Cuba); CINVESTAV-Unidad Querétaro, IPN, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, CP. 76230 Querétaro, Querétaro (Mexico); Guerra, J. D. S. [Grupo de Ferroelétricos e Materiais Multifuncionais, Instituto de Física, Universidade Federal de Uberlândia, MG (Brazil); Yañez-Limón, J. M. [CINVESTAV-Unidad Querétaro, IPN, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, CP. 76230 Querétaro, Querétaro (Mexico)

    2014-07-28

    Over the past several years, there has been a remarkable growth and development in new ceramic and/or composite materials to be used in the electro-electronic industry. Ferroelectric materials have been recognized for their multifunctional physical properties; also, their optical properties are a subject of intense research effort due to their possible electro-optic applications. In this work, the visible photoluminescence effect is analyzed at room temperature in a sintered Pb{sub 0.95}Sr{sub 0.05}(Zr{sub 1−x}Ti{sub x}){sub 1−y}Cr{sub y}O{sub 3} perovskite-type structure system, doped with Sr and Cr. The excitation bands used were 267, 325, 373, 457, 635, and 680 nm, but the best result was obtained at 373 nm. The intensity and energy of such emission in this system have been studied by changing the molar Cr concentration (0 < y < 0.005) and the Ti content (x), with x = 0.20, 0.40, 0.53, 0.60, and 0.80, on both sides of the morphotropic phase boundary (MPB) zone. The principal emission bands are at the energies 1.73, 1.87, and 3.03 eV. The changes that were caused by Zr or Ti ions in the symmetry presented in the rhombohedral or tetragonal side of the MPB are more important. Additionally, structural and micro-structural measurements were performed by the x-ray diffraction and scanning electron microscopy techniques, respectively. The micro-Raman technique is also used in the study of this set of samples, which allows finding the Raman shift modes and the influence on the structural changes of the dopants.

  17. A study on crystalline phases present in the as-solidified and crystallized microstructures in Zr53Cu21Al10Ni8Ti8 alloy

    International Nuclear Information System (INIS)

    Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.

    2011-01-01

    In the present study the as-solidified and crystallized microstructures of Zr 53 Cu 21 Al 10 Ni 8 Ti 8 alloy have been examined in detail. Solidification was carried out by melt spinning, suction casting and copper mould casting techniques. The last technique yielded a partially crystalline microstructure, whereas, the other two techniques resulted in amorphous microstructures. (author)

  18. Analysis of Light Gathering Abilities of Dynamically Solidified Micro-lenses, and Their Implementation to Improve Sensitivity of Fluorescent PCR Micro-detectors.

    Science.gov (United States)

    Wu, Jian; Guo, Wei; Wang, Chunyan; Yu, Kuanxin; Chen, Tao; Li, Yinghui

    2015-06-01

    Fluorescent polymerase chain reaction (PCR) is becoming the preferred method of quantitative analysis due to its high specificity and sensitivity. We propose to use a new kind of micro-lens, dynamically solidified with optic glue, to improve the sensitivity of fluorescent PCR micro-detector. We developed light ray track equations for these lenses and used them to calculate relative light intensity distribution curve for stimulation lenses and illumination point probability distribution curve for detection lenses. We manufactured dynamically solidified micro-lenses using optic glue NOA61, and measured their light gathering ability. Lenses with radius/thickness (R/H) ratio of 4 reached light focusing ratio of 3.85 (stimulation lens) and photon collection efficiency of 0.86 (detection lens). We then used dynamically solidified lenses in PCR fluorescence micro-detector and analyzed their effect on the detector sensitivity. We showed that the use of dynamically solidified micro-lenses with R/H = 4 resulted in over 4.4-fold increased sensitivity of the detector.

  19. Experimental study on the properties of drum-packed, cement solidified waste package of pre and after sea dumping test of sea depth 30m and 100m

    International Nuclear Information System (INIS)

    Maki, Yasuro; Abe, Hirotoshi; Hattori, Seiichi

    1976-01-01

    Japan Marine Science and Technology Center has been tackling with the development of the monitoring system to confirm the soundness of drum-packed, cement-solidified low level radioactive waste (the package) during falling and after reaching at sea bed when it is dumped into sea. The test was carried out at Sagami Bay of 30 m and 100 m sea depth using non-radioactive packages. The observation of the falling behaviour of packages in sea was carried out by taking photographs of the motion of packages with an underwater 16 mm movie camera and an underwater industrial TV (ITV), and the observation of the soundness and the area of packages scattered on sea bed was carried out with an underwater ITV and an underwater 70 mm snap camera which were set up on the frame. The proportion of cement-solidified waste was decided so that the uni-axial compressive strength of the cement-solidified waste satisfies the condition of ''The tentative guideline''. Prior to tests at sea, hydrostatic pressure test of packages are carried out on land. After that, core specimens were sampled to obtain the uniaxial compressive strength from packages and were tested. After sea dumping tests, 6 packages were recovered from sea bed, and the soundness were tested. As the results, the deformation and damage of drums and cement solidified waste packages did not occur at all. (Kako, I.)

  20. Assessment of phase constitution on the Al-rich region of rapidly solidified Al-Co-Fe-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, W., E-mail: witorw@gmail.com [Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil); Bolfarini, C., E-mail: cbolfa@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil); Kiminami, C.S., E-mail: kiminami@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil); Botta, W.J., E-mail: wjbotta@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, Km 235, 13565-905 São Carlos, SP (Brazil)

    2016-12-15

    The formation of quasicrystalline approximants in rapidly solidified Al-Co-Fe-Cr alloys was investigated. Alloys of atomic composition Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8}, Al{sub 77}Co{sub 11}Fe{sub 6}Cr{sub 6} and Al{sub 76}Co{sub 19}Fe{sub 4}Cr{sub 1} were produced using melt spinning and arc melting methods and their microstructural characterization was carried out by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Up to the present there is no consensus in the literature regarding the formation of quasicrystalline phase or quasicrystalline approximants in the Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8} alloy. This work presents, for the first time, a detailed structural characterization of selected alloys in the Al-Co-Fe-Cr system close to the atomic composition Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8}. The results indicated the samples to be composed, mostly, by two intermetallic phases, which are quaternary extensions of Al{sub 5}Co{sub 2} and Al{sub 13}Co{sub 4} and are quasicrystalline approximants. Although the Al{sub 5}Co{sub 2} phase has already been reported in the Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8} alloy, the presence of the monoclinic Al{sub 13}Co{sub 4} is now identified for the first time in the as cast state. In the binary Al-Co system a quasicrystalline phase is known to form in a rapidly solidified alloy with composition close to the monoclinic and orthorhombic Al{sub 13}Co{sub 4} phases. This binary quasicrystalline phase presents an average valence electron per atom (e/a) between 1.7 and 1.9; thus, in addition to the Al{sub 71}Co{sub 13}Fe{sub 8}Cr{sub 8} alloy, the compositions Al{sub 77}Co{sub 11}Fe{sub 6}Cr{sub 6} and Al{sub 76}Co{sub 19}Fe{sub 4}Cr{sub 1} were chosen to be within the region of formation of the quaternary extension of the Al{sub 13}Co{sub 4} phase and also within the (e/a) of 1.7 to 1.9. However, no quasicrystalline phase is present in any of the studied alloys. The Al-Co-Fe-Cr system

  1. Assessment of phase constitution on the Al-rich region of rapidly solidified Al-Co-Fe-Cr alloys

    International Nuclear Information System (INIS)

    Wolf, W.; Bolfarini, C.; Kiminami, C.S.; Botta, W.J.

    2016-01-01

    The formation of quasicrystalline approximants in rapidly solidified Al-Co-Fe-Cr alloys was investigated. Alloys of atomic composition Al 71 Co 13 Fe 8 Cr 8 , Al 77 Co 11 Fe 6 Cr 6 and Al 76 Co 19 Fe 4 Cr 1 were produced using melt spinning and arc melting methods and their microstructural characterization was carried out by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Up to the present there is no consensus in the literature regarding the formation of quasicrystalline phase or quasicrystalline approximants in the Al 71 Co 13 Fe 8 Cr 8 alloy. This work presents, for the first time, a detailed structural characterization of selected alloys in the Al-Co-Fe-Cr system close to the atomic composition Al 71 Co 13 Fe 8 Cr 8 . The results indicated the samples to be composed, mostly, by two intermetallic phases, which are quaternary extensions of Al 5 Co 2 and Al 13 Co 4 and are quasicrystalline approximants. Although the Al 5 Co 2 phase has already been reported in the Al 71 Co 13 Fe 8 Cr 8 alloy, the presence of the monoclinic Al 13 Co 4 is now identified for the first time in the as cast state. In the binary Al-Co system a quasicrystalline phase is known to form in a rapidly solidified alloy with composition close to the monoclinic and orthorhombic Al 13 Co 4 phases. This binary quasicrystalline phase presents an average valence electron per atom (e/a) between 1.7 and 1.9; thus, in addition to the Al 71 Co 13 Fe 8 Cr 8 alloy, the compositions Al 77 Co 11 Fe 6 Cr 6 and Al 76 Co 19 Fe 4 Cr 1 were chosen to be within the region of formation of the quaternary extension of the Al 13 Co 4 phase and also within the (e/a) of 1.7 to 1.9. However, no quasicrystalline phase is present in any of the studied alloys. The Al-Co-Fe-Cr system, around the compositions studied, is composed of quaternary extensions of Al-Co intermetallic phases, which present solubility of Fe and Cr at Co atomic sites. - Highlights: •The Al rich region of the Al

  2. Phase evolution and aqueous durability of Zr{sub 1−x−y}Ce{sub x}Nd{sub y}O{sub 2−y/2} ceramics designed to immobilize actinides with multi-valences

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yi, E-mail: dingyi2279@126.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Key Subject Laboratory of National Defense for Radioactive Waste and Environmental Security, Southwest University of Science and Technology, Mianyang 621010 (China); Long, Xinggui, E-mail: xingguil@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Peng, Shuming [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Zhang, Dong, E-mail: zd0823@sina.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Tan, Zhaoyi [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, Sichuan, 621900 (China); Lu, Xirui [Key Subject Laboratory of National Defense for Radioactive Waste and Environmental Security, Southwest University of Science and Technology, Mianyang 621010 (China)

    2017-04-15

    Zr{sub 1−x−y}Ce{sub x}Nd{sub y}O{sub 2−y/2} ceramics, which were designed as waste form materials, were obtained by simultaneous substitution of Ce{sup 4+} and Nd{sup 3+} for Zr{sup 4+} in ZrO{sub 2}. The influences of the simultaneous substitution of Ce and Nd on phase transformation of ZrO{sub 2} were investigated systematically. Also, the aqueous durability of the ceramics was evaluated. The results show that the phase transformation caused by the simultaneous substitution mainly relates to the total content of Ce and Nd. The ZrO{sub 2} ceramics containing Ce + Nd < 30 mol% exhibit both monoclinic and cubic phases, while the ceramics containing Ce + Nd ≥ 30 mol% are cubic phase. And the cubic phase can be stabilized by incorporating 30 mol% Ce + Nd. Moreover, LR{sub i} are modified by the incorporation of Ce and Nd, because of the presence of oxygen vacancies. The Nd and Ce co-doped zirconia waste form exhibit excellent aqueous durability (∼10{sup −5} g m{sup −2} d{sup −1}). - Highlights: •Zr{sub 1−x−y}Ce{sub x}Nd{sub y}O{sub 2−y/2} were obtained by substitution of Ce and Nd for Zr in ZrO{sub 2}. •Phase transformation mainly relates to the total content of Ce and Nd. •Samples with Ce + Nd < 30 mol% show monoclinic and cubic phases, while ≥30 mol% are cubic. •Stabilized cubic zirconia can be obtained by doping with 30 mol% Ce and Nd. •LR{sub Ce} and LR{sub Nd} (42 d) are ∼ 10{sup −5} g m{sup −2} d{sup −1}, exhibiting excellent aqueous durability.

  3. Thermal cycling behavior of YSZ and La{sub 2}(Zr{sub 0.7}Ce{sub 0.3}){sub 2}O{sub 7} as double-ceramic-layer systems EB-PVD TBCs

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhenhua, E-mail: zhxuciac@yahoo.com [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); He Limin; Mu Rende; Lu Feng; He Shimei [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao Xueqiang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-06-05

    Highlights: Black-Right-Pointing-Pointer DCL coating has a longer lifetime than that of single layer coating of LZ7C3 or YSZ. Black-Right-Pointing-Pointer The unique growth modes of columns within DCL coating. Black-Right-Pointing-Pointer The presence of cerium in both Ce{sup 3+} and Ce{sup 4+} oxidation states within the coating surface. Black-Right-Pointing-Pointer The spallation of DCL coating induced by transverse cracks may be the first emergence of delamination followed by spalling layer by layer. Black-Right-Pointing-Pointer The outward diffusion of Cr element (bond coat) into LZ7C3 layer. - Abstract: Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La{sub 2}(Zr{sub 0.7}Ce{sub 0.3}){sub 2}O{sub 7} (LZ7C3) and yttria stabilized zirconia (YSZ) were deposited by electron beam-physical vapor deposition (EB-PVD). The thermal cycling test at 1573 K in burner-rig with a coal gas flame indicates the thermal cycling life of DCL coating is not only much longer than that of LZ7C3 coating, but also approximately 27% longer than that of YSZ coating. The superior sintering-resistance of LZ7C3 coating and the unique growth modes of columns within DCL coating are all very helpful to the prolongation of thermal cycling life of DCL coating. The failure of DCL coating is mainly a result of the reduction-oxidation of cerium oxide, the re-crystallization of some LZ7C3 fine grains, the cracks initiation, propagation and extension, the abnormal oxidation of bond coat, the degradation of t Prime -phase in YSZ coating and the outward diffusion of Cr alloying element into LZ7C3 coating. Since no single material that has been studied so far satisfies all the requirements for high temperature applications, DCL coating is an important development direction of TBCs.

  4. Influence of micro-additions of bismuth on structures, mechanical and electrical transport properties of rapidly solidified Sn-3.5% Ag Alloy from melt

    International Nuclear Information System (INIS)

    El Bahay, M.M.; Mady, H.A.

    2005-01-01

    The present study was undertaken to investigate the influence of the Bi addition in the Sn-3.5 Ag rapidly solidified binary system for use as a Pb-free solder. The resulting properties of the binary system were extended to the Sn based ternary systems Sn 9 6.5-X Ag 3 .5 Bi x (0≤ X ≤ 2.5) solder. The structure and electrical resistivity of rapidly solidified (melt spun) alloys have been investigated. With the addition of up to 2.5 mass % Bi, the melting temperature decreases from 221.1 to 214.8 degree C. Wetting contact angle of the six alloys on Cu Zn 3 0 substrate are carried out at 573 K. Microhardness evaluations were also performed on the Sn-Ag-Bi alloys. The measured values and other researcher's results were compared with the calculated data

  5. Variation of long-period stacking order structures in rapidly solidified Mg97Zn1Y2 alloy

    International Nuclear Information System (INIS)

    Matsuda, M.; Ii, S.; Kawamura, Y.; Ikuhara, Y.; Nishida, M.

    2005-01-01

    The long-period stacking order (LPSO) structures in rapidly solidified Mg 97 Zn 1 Y 2 alloy have been studied by conventional and high-resolution transmission electron microscopes (HRTEMs). There are four kinds of stacking sequences in the LPSO structures, i.e., 18R of ABABABCACACABCBCBC, 14H of ACBCBABABABCBC, 10H of ABACBCBCAB and 24R of ABABABABCACACACABCBCBCBC. The 18R structure is dominantly observed in the present study. The rest three are occasionally observed in places. The 10H and 24R structures are recently discovered. The lattice constants of 18R(1-bar 1-bar -bar 1-bar 1-bar -bar 2) 3 , 14H(2-bar -bar 1-bar 2-bar -bar 1-bar 1-bar -bar 1-bar 1-bar -bar 2-bar 1-bar -bar 2), 10H(1-bar 3-bar -bar 1-bar 1-bar -bar 3-bar 1-bar ) and 24R(1-bar 1-bar -bar 1-bar 1-bar -bar 1-bar 1-bar -bar 2) 3 structures are estimated to be a=0.320nm and c=4.678nm, a=0.325nm and c=3.694nm, a=0.325nm and c=2.603nm, a=0.322nm and c=6.181nm for the hexagonal structure, respectively

  6. Formation of equiaxed crystal structures in directionally solidified Al-Si alloys using Nb-based heterogeneous nuclei

    Science.gov (United States)

    Bolzoni, Leandro; Xia, Mingxu; Babu, Nadendla Hari

    2016-01-01

    The design of chemical compositions containing potent nuclei for the enhancement of heterogeneous nucleation in aluminium, especially cast alloys such as Al-Si alloys, is a matter of importance in order to achieve homogeneous properties in castings with complex geometries. We identified that Al3Nb/NbB2 compounds are effective heterogeneous nuclei and are successfully produced in the form of Al-2Nb-xB (x = 0.5, 1 and 2) master alloys. Our study shows that the inoculation of Al-10Si braze alloy with these compounds effectively promotes the heterogeneous nucleation of primary α-Al crystals and reduces the undercooling needed for solidification to take place. Moreover, we present evidences that these Nb-based compounds prevent the growth of columnar crystals and permit to obtain, for the first time, fine and equiaxed crystals in directionally solidified Al-10Si braze alloy. As a consequence of the potent heterogeneous particles, the size of the α-Al crystals was found to be less dependent on the processing conditions, especially the thermal gradient. Finally, we also demonstrate that the enhanced nucleation leads to the refinement of secondary phases such as eutectic silicon and primary silicon particles. PMID:28008967

  7. Long-term reactive transport modelling of stabilized/solidified waste: from dynamic leaching tests to disposal scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Windt, Laurent de [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)]. E-mail: laurent.dewindt@ensmp.fr; Badreddine, Rabia [INERIS, Direction des Risques Chroniques, Unite Dechets et Sites Pollues, Parc Technologique Alata BP 2, 60550 Verneuil-en-Halatte (France); Lagneau, Vincent [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)

    2007-01-31

    Environmental impact assessment of hazardous waste disposal relies, among others, on standardized leaching tests characterized by a strong coupling between diffusion and chemical processes. In that respect, this study shows that reactive transport modelling is a useful tool to extrapolate laboratory results to site conditions characterized by lower solution/solid (L/S) ratios, site specific geometry, infiltration, etc. A cement solidified/stabilized (S/S) waste containing lead is investigated as a typical example. The reactive transport model developed in a previous study to simulate the initial state of the waste as well as laboratory batch and dynamic tests is first summarized. Using the same numerical code (HYTEC), this model is then integrated to a simplified waste disposal scenario assuming a defective cover and rain water infiltration. The coupled evolution of the S/S waste chemistry and the pollutant plume migration are modelled assessing the importance of the cracking state of the monolithic waste. The studied configurations correspond to an undamaged and fully sealed system, a few main fractures between undamaged monoliths and, finally, a dense crack-network in the monoliths. The model considers the potential effects of cracking, first the increase of rain water and carbon dioxide infiltration and, secondly, the increase of L/S ratio and reactive surfaces, using either explicit fracture representation or dual porosity approaches.

  8. High damping Al-Fe-Mo-Si/Zn-Al composites produced by rapidly solidified powder metallurgy process

    International Nuclear Information System (INIS)

    Li, P.Y.; Dai, S.L.; Chai, S.C.; Li, Y.R.

    2000-01-01

    The metallic materials commonly used in aircraft and aerospace fields, such as aluminum and titanium alloys, steels, etc., show extremely low damping capacity (usually of the order of or less than 10 -3 ). Thus, some problems related to vibration may emerge and influence the reliability, safety and life of airplanes, satellites, etc. It has been reported that almost two thirds of errors for rockets and satellites are related to vibration and noise. One effective way to solve these vibration-related problems is to adopt high damping metallic materials. Conventional high damping alloys exhibit damping capacity above 10 -2 , however, their densities are usually great than 5 x 10 3 kg m -3 , or their strengths are less than 200 MPa (for alloys based on dislocation damping), making them impossible to be applied to aircraft and aerospace areas. Recently, some low-density high-damping metal/metal composites based on aluminum and high damping alloys have been developed in Beijing Institute of Aeronautical Materials (BIAM) by the rapidly solidified power metallurgy process. This paper aims to report the properties of the composites based on a high temperature Al-Fe-Mo-Si alloy and a high damping Zn-Al alloy, and compare them with that of 2618-T61 alloy produced by the ingot metallurgy process

  9. Effect of Trace Ce on Microstructure and Properties of Near-rapidly Solidified Al-Zn-Mg-Cu Alloys

    Directory of Open Access Journals (Sweden)

    HUANG Gao-ren

    2018-03-01

    Full Text Available Through using DSC, XRD, SEM, EDS, static tensile test and other analysis methods of materials, the effect of trace Ce on microstructure and properties of near-rapidly solidified Al-Zn-Mg-Cu alloy was studied in order to find out rational homogenizing heat treatment process. The results show that Ce plays a role of refining grain and purifying molten alloy. The addition of Ce reduces dendritic spacing, refines the grain structures, eliminates dispersed shrinkage. The addition of Ce reduces the initial melting point of low melting eutectic phases by 3℃, under the same homogenization conditions. Trace Ce promotes the dissolution of low melting eutectic phases into the matrix, which improves the effect of homogenization. Homogenization temperatures of alloy A should be lower than 480℃and alloy B should be lower than 470℃; the addition of Ce decreases the homogenization temperature and improves the homogenization effect. The addition of Ce also greatly increases the tensile strength of the alloys.

  10. Mechanism of nucleation and growth of hydrogen porosity in solidifying A356 aluminum alloy: an analytical solution

    International Nuclear Information System (INIS)

    Li, K.-D.; Chang, Edward

    2004-01-01

    This study derives an analytical solution for the mechanism of nucleation and growth of hydrogen pore in the solidifying A356 aluminum alloy. A model of initial transient hydrogen redistribution in the growing dendritic grain is used to modify the lever rule for the mechanism of nucleation of pore. The model predicts the fraction of solid at nucleation, the temperature range of nucleation, the radius of hydrogen diffusion cell, and the supersaturation of hydrogen needed for nucleation. The role of solidus velocity in nucleation is explained. The parameters calculated from the model of nucleation are used for analyzing the mechanism of kinetic diffusion-controlled growth of pore, in which the mathematical transformations of variables are introduced. With the transformations, it is argued that the diffusion problem involving the liquid and solid phases during solidification could be treated as a classic problem of precipitation in the single-phase medium treated by Ham or Avrami. The analytical solution for the nucleation of pore is compared with the mechanism of macrosegregation. The predicted volume percent of porosity and radius of pore based on the mechanism of growth of pore is discussed with respect to the thermodynamic solution, the published experimental data, the numerical solutions, and the role of interdendritic fluid flow governed by Darcy's law

  11. Macrosegregation During Re-melting and Holding of Directionally Solidified Al-7 wt.% Si Alloy in Microgravity

    Science.gov (United States)

    Lauer, M.; Ghods, M.; Angart, S. G.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2017-08-01

    As-cast aluminum-7 wt.% ailicon alloy sample rods were re-melted and directionally solidified on Earth which resulted in uniform dendritically aligned arrays. These arrays were then partially back-melted through an imposed, and constant, temperature gradient in the microgravity environment aboard the International Space Station. The mushy zones that developed in the seed crystals were held for different periods prior to initiating directional solidification. Upon return, examination of the initial mushy-zone regions exhibited significant macrosegregation in terms of a solute-depleted zone that increased as a function of the holding time. The silicon (solute) content in these regions was measured on prepared longitudinal sections by electron microprobe analysis as well as by determining the fraction eutectic on several transverse sections. The silicon content was found to increase up the temperature gradient resulting in significant silicon concentration immediately ahead of the mushy-zone tips. The measured macrosegregation agrees well with calculations from a mathematical model developed to simulate the re-melting and holding process. The results, due to processing in a microgravity environment where buoyancy and thermosolutal convection are minimized, serve as benchmark solidification data.

  12. Evolution of the microstructure and nanohardness of Ti-48 at.%Al alloy solidified under high pressure

    International Nuclear Information System (INIS)

    Wang, Hongwei; Zhu, Dongdong; Zou, Chunming; Wei, Zunjie

    2012-01-01

    Highlights: → The microstructure of Ti-48Al alloy changes under high pressure. → With increasing pressure, the amount of γ s phase decreases. → High pressure leads to the decreasing of lamellar spacing. → The nanohardness of lamellar structure increases with pressure. -- Abstract: In this work the microstructure and nanohardness of Ti-48 at.%Al alloy solidified under different pressures (normal pressure, 2 GPa, 4 GPa) were experimental investigated by using a tungsten-carbide six-anvil apparatus. The results indicate that high pressure does not change the phase constitution of Ti-48 at.%Al alloy. However, the microstructure changes under high pressure. With increasing pressure, the volume fraction of interdendritic γ (γ s ) phase decreases and Al concentration in lamellae increases. When the pressure is 4 GPa, there is only a little γ s embedded in lamellar structure. The volume fraction of γ s phase is approximately 17.0% for normal pressure, 8.73% for 2 GPa, 0.69% for 4 GPa. The lamellar spacings also decrease with pressure, which are 495 nm, 345 nm, 227 nm under normal pressure, 2 GPa, 4 GPa, respectively. The change in nanohardness was discussed based on the microstructural observations. It shows a certain increase of the nanohardness as the pressure increases from normal pressure to 4 GPa. When the pressure is 4 GPa, the nanohardness increases by 50.2% compared with that of normal pressure.

  13. Sensitive determination of cadmium using solidified floating organic drop microextraction-slotted quartz tube-flame atomic absorption spectroscopy.

    Science.gov (United States)

    Akkaya, Erhan; Chormey, Dotse Selali; Bakırdere, Sezgin

    2017-09-20

    In this study, solidified floating organic drop microextraction (SFODME) by 1-undecanol was combined with slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) for the determination of cadmium at trace levels. Formation of a complex with 4,4'-dimethyl-2,2'-bipyridine facilitated the extraction of cadmium from aqueous solutions. Several chemical variables were optimized in order to obtain high extraction outputs. Parameters such as concentration of the ligand, pH, and amount of buffer solution were optimized to enhance the formation of cadmium complex. The SFODME method was assisted by dispersion of extractor solvent into aqueous solutions using 2-propanol. Under the optimum extraction and instrumental conditions, the limit of detection and limit of quantitation values obtained for cadmium using the combined methods (SFODME-SQT-FAAS) were found to be 0.4 and 1.3 μg L -1 , respectively. Matrix effects on the method were also examined for tap water and wastewater, and spiked recovery results were found to be very satisfactory. Graphical Abstract SFODME-SQT-FAAS system for sensitive determination of cadmium.

  14. The influence of Si and V on the kinetics of phase transformation and microstructure of rapidly solidified Al-Fe-Zr alloys

    OpenAIRE

    Karpe B.; Kosec B.; Nagode A.; Bizjak M.

    2013-01-01

    The influence of Si and V on the precipitation kinetics of the rapidly solidified (RS) Al-Fe-Zr alloys is presented. Precipitation kinetics and microstructural development of RS Al-Fe-Zr alloys with Si or V addition have been investigated by the combination of four point electrical resistance measurement, optical microscopy, transmition electron microscopy (TEM) and scanning electron microscopy (SEM). For verification of the electrical resistivity measurement results differential scanni...

  15. Microtexture formation of Ni99B1 alloys solidified on an ESL and an EML-a study based on the EBSP technique

    International Nuclear Information System (INIS)

    Li Mingjun; Ishikawa, Takehiko; Nagashio, Kosuke; Kuribayashi, Kazuhiko; Yoda, Shinichi

    2007-01-01

    We employed an electrostatic levitator (ESL) and an electromagnetic levitator (EML) to solidify Ni 99 B 1 (at.%) alloys at various undercoolings. The microstructures and microtextures were revealed by using the electron backscatter diffraction pattern (EBSP) technique in a scanning electron microscope. It is found that that no significant refinement can be identified at the low and medium undercooling regimes for the primary trunk in the sample solidified on the ESL, while the fragmentation of the secondary and even tertiary branches may take place to generate equiaxed grains. Further investigation by the EBSP reveals that neighboring grains have small misorientation angles, which may be ascribed to the absence of mechanical stirring from electromagnetic eddy current. A sharp contrast is that the samples solidified on the EML at low and medium undercoolings have refined equiaxed microstructures. The EBSP mapping reveals that the equiaxed grains yielded on the EML have a random distribution in crystallographic orientations among neighboring grains, indicating that electromagnetic stirring (EMS) induced by the electromagnetic field in the EML plays a vital role in promoting fragmentation and thus generating refined grains and random distribution in orientation. Regarding to the refined microstructure at high undercoolings, no significant difference arises in the samples processed between the EML and ESL

  16. A comparative EBSP study of microstructure and microtexture formation from undercooled Ni99B1 melts solidified on an electrostatic levitator and an electromagnetic levitator

    International Nuclear Information System (INIS)

    Li Mingjun; Ishikawa, Takehiko; Nagashio, Kosuke; Kuribayashi, Kazuhiko; Yoda, Shinichi

    2006-01-01

    Ni 99 B 1 alloys were solidified by containerless processing at various melt undercoolings on an electrostatic levitator (ESL) and an electromagnetic levitator (EML). A scanning electron microscope in combination with an electron backscatter diffraction pattern mapping technique was employed to reveal microstructures and microtextures formed on these two facilities. The microstructure consists of well-developed primary dendrites with coarse secondary arms in the alloys solidified on the ESL at low and medium undercooling levels, whereas equiaxed grains are yielded in alloys solidified on the EML at almost the same undercoolings. Further analysis indicates that the melt flow induced by the electromagnetic field in the EML may play a significant role in promoting fragmentation of primary dendrites in the mushy zone and thus resulting in equiaxed grains. In contrast, the primary dendrites in the alloy processed on the ESL can fully develop in the absence of melt flow. The fluid flow in the sample on the EML can rotate, move, and displace surviving fragments, yielding a random distribution of grain orientation and thus leading to a random microtexture at low and medium undercoolings. At high undercoolings, refined equiaxed grains can be obtained on both the ESL and the EML and the influence of melt flow on refinement seems negligible due to the enhanced driving force in capillarity and solute effects. A great number of coherent annealing twins are formed, making the pole figures more complex and random

  17. Microtexture formation of Ni{sub 99}B{sub 1} alloys solidified on an ESL and an EML-a study based on the EBSP technique

    Energy Technology Data Exchange (ETDEWEB)

    Li Mingjun [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Tsukuba Space Center, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan)], E-Mail: li.mingjun@aist.go.jp; Ishikawa, Takehiko [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Tsukuba Space Center, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan); Nagashio, Kosuke [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara Campus, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Kuribayashi, Kazuhiko [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara Campus, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Yoda, Shinichi [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Tsukuba Space Center, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan)

    2007-03-25

    We employed an electrostatic levitator (ESL) and an electromagnetic levitator (EML) to solidify Ni{sub 99}B{sub 1} (at.%) alloys at various undercoolings. The microstructures and microtextures were revealed by using the electron backscatter diffraction pattern (EBSP) technique in a scanning electron microscope. It is found that that no significant refinement can be identified at the low and medium undercooling regimes for the primary trunk in the sample solidified on the ESL, while the fragmentation of the secondary and even tertiary branches may take place to generate equiaxed grains. Further investigation by the EBSP reveals that neighboring grains have small misorientation angles, which may be ascribed to the absence of mechanical stirring from electromagnetic eddy current. A sharp contrast is that the samples solidified on the EML at low and medium undercoolings have refined equiaxed microstructures. The EBSP mapping reveals that the equiaxed grains yielded on the EML have a random distribution in crystallographic orientations among neighboring grains, indicating that electromagnetic stirring (EMS) induced by the electromagnetic field in the EML plays a vital role in promoting fragmentation and thus generating refined grains and random distribution in orientation. Regarding to the refined microstructure at high undercoolings, no significant difference arises in the samples processed between the EML and ESL.

  18. Microstructure formation and in situ phase identification from undercooled Co-61.8 at.% Si melts solidified on an electromagnetic levitator and an electrostatic levitator

    Energy Technology Data Exchange (ETDEWEB)

    Li Mingjun [National Institute of Advanced Industrial Science and Technology (AIST), Materials Research Institute for Sustainable Development, 2266-98 Shimo-Shidami, Moriyama, Nagoya, Aichi 463-8560 (Japan); Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Science (ISAS), Tsukuba Space Centre, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan)], E-mail: li.mingjun@aist.go.jp; Nagashio, Kosuke [Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Science (ISAS), Sagamihara Campus, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Ishikawa, Takehiko [Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Science (ISAS), Tsukuba Space Centre, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan); Mizuno, Akitoshi; Adachi, Masayoshi; Watanabe, Masahito [Department of Physics, Gakushuin University, 1-5-1 Mejiro, Toshima, Tokyo 171-8588 (Japan); Yoda, Shinichi [Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Science (ISAS), Tsukuba Space Centre, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan); Kuribayashi, Kazuhiko [Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Science (ISAS), Sagamihara Campus, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Katayama, Yoshinori [Japan Atomic Energy Agency (JAEA), 1-1-1 Kouto, Mikazuki, Sayo, Hyogo 679-5148 (Japan)

    2008-06-15

    Co-61.8 at.% Si (CoSi-CoSi{sub 2}) eutectic alloys were solidified on an electromagnetic levitator (EML) and an electrostatic levitator (ESL) at different undercooling levels. The results indicated that there is only a single recalescence event at low undercooling with the CoSi intermetallic compound as primary phase, which is independent of processing facilities, on either an EML or an ESL. The microstructure, however, is strongly dependent on the processing facility. The interior melt flow behavior in the sphere solidified at the EML differs substantially from that at the ESL, thus yielding different microstructures. On high undercooling, double recalescence takes place regardless of levitation condition. In situ X-ray diffraction of alloys solidified on the EML demonstrates that the CoSi{sub 2} compound becomes the primary phase upon the first recalescence, and the CoSi intermetallic phase crystallizes during the second recalescence. In addition to phase identification, real-time diffraction patterns can also provide additional evidence of the fragmentation of the primary phase and the ripening feature in the subsequent cooling process in the semisolid state. The phase competition between the CoSi and CoSi{sub 2} compounds is discussed when considering the nucleation barrier. The low interfacial energy of the CoSi{sub 2} phase favors a preferential nucleation event over the CoSi phase, which also plays a critical role in non-reciprocity nucleation and thus yields a double recalescence profile at high undercooling.

  19. Examination of solidified and stabilized matrices as a result of solidification and stabilization process of arseniccontaining sludge with portland cement and lime

    Directory of Open Access Journals (Sweden)

    Tanapon Phenrat

    2004-02-01

    Full Text Available By solidification and stabilization (S/S with Portland cement and lime, it is possible to reduce arsenic concentration in leachate of the arsenic-containing sludge from arsenic removal process by coagulation with ferric chloride. From the initial arsenic concentration in leachate of unsolidified /unstabilized sludge which was around 20.75 mg/L, the arsenic concentrations in leachate of solidified/stabilized waste were reduced to 0.3, 0.58, 1.09, and 1.85 mg/L for the waste-to-binder ratios of 0.15, 0.25, 0.5, and 1, respectively, due tothe formation of insoluble calcium-arsenic compounds. To be more cost effective for the future, alternative uses of these S/S products were also assessed by measurement of compressive strength of the mortar specimens. It was found that the compressive strengths of these matrices were from 28 ksc to 461 ksc. In conclusion, considering compressive strength and leachability of the solidified matrices, some of these solidified/ stabilized products have potential to serve as an interlocking concrete paving block.

  20. Resistance to He{sup 2+} induced irradiation damage in metallic glass Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bin [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Zhang, Hongran; Hou, Wenjing; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

    2014-01-15

    Graphical abstract: This paper used TEM for the analysis of the microstructure, helium bubble distribution and helium bubble growth process of Zr-based metallic glass after the irradiation at maximum fluence. Fig. a shows the cross-sectional TEM sample morphology image of Zr-based metallic glass. It could be observed that a large number of helium bubbles were distributed on the topmost surface of Zr-based metallic glass (Zone A in Fig.a). The helium bubbles on the surface were mostly round, except for a small number of irregular-shape bubbles, with the sizes ranging from several nanometers to several tens of nanometers. The helium bubble diameter became gradually smaller downwardly from Zone A. As shown in Fig.a, the helium bubble size was small within the range of 0.3–1.2 μm below the surface (Zone B), and a large number of helium bubbles with a diameter of several nanometers were uniformly distributed in the area close to Zone A and Zone C; as shown in Fig.b, a helium bubble layer appeared within the range of 1.2–1.5 μm (Zone C) away from the surface, and it was found that the helium bubble size was larger in the vicinity of 1.3 μm away from the surface. Fig.b shows the atom vacancy distribution curves in Zr-based metallic glass before and after the helium ion irradiation obtained through SRIM program simulation. It could be observed that vacancy concentration peaks appeared at the ion range of 1.2 μm, and a large number of vacancies were concentrated at the end of the range. The vacancies of the sample were very easy to capture helium atoms and were conducive to the formation and growth of helium bubbles. -- Highlights: • Metallic glass could maintain amorphous state at different irradiation fluences. • A damage layer appeared in Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5} at a fluence of 2 × 10{sup 18} ions/cm{sup 2}. • Peeling and delamination appeared numerously in W at a fluence of 1 × 10{sup 18} ions/cm{sup 2}. • Lots of helium bubbles

  1. Cooling thermal parameters and microstructure features of directionally solidified ternary Sn–Bi–(Cu,Ag) solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Bismarck L., E-mail: bismarck_luiz@yahoo.com.br [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, 13083-860 Campinas, SP (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil)

    2016-04-15

    Low temperature soldering technology encompasses Sn–Bi based alloys as reference materials for joints since such alloys may be molten at temperatures less than 180 °C. Despite the relatively high strength of these alloys, segregation problems and low ductility are recognized as potential disadvantages. Thus, for low-temperature applications, Bi–Sn eutectic or near-eutectic compositions with or without additions of alloying elements are considered interesting possibilities. In this context, additions of third elements such as Cu and Ag may be an alternative in order to reach sounder solder joints. The length scale of the phases and their proportions are known to be the most important factors affecting the final wear, mechanical and corrosions properties of ternary Sn–Bi–(Cu,Ag) alloys. In spite of this promising outlook, studies emphasizing interrelations of microstructure features and solidification thermal parameters regarding these multicomponent alloys are rare in the literature. In the present investigation Sn–Bi–(Cu,Ag) alloys were directionally solidified (DS) under transient heat flow conditions. A complete characterization is performed including experimental cooling thermal parameters, segregation (XRF), optical and scanning electron microscopies, X-ray diffraction (XRD) and length scale of the microstructural phases. Experimental growth laws relating dendritic spacings to solidification thermal parameters have been proposed with emphasis on the effects of Ag and Cu. The theoretical predictions of the Rappaz-Boettinger model are shown to be slightly above the experimental scatter of secondary dendritic arm spacings for both ternary Sn–Bi–Cu and Sn–Bi–Ag alloys examined. - Highlights: • Dendritic growth prevailed for the ternary Sn–Bi–Cu and Sn–Bi–Ag solder alloys. • Bi precipitates within Sn-rich dendrites were shown to be unevenly distributed. • Morphology and preferential region for the Ag{sub 3}Sn growth depend on Ag

  2. Electrochemical properties of rapidly solidified Si-Ti-Ni(-Cu) base anode for Li-ion rechargeable batteries

    Science.gov (United States)

    Kwon, Hye Jin; Sohn, Keun Yong; Park, Won-Wook

    2013-11-01

    In this study, rapidly solidified Si-Ti-Ni-Cu alloys have been investigated as high capacity anodes for Li-ion secondary batteries. To obtain nano-sized Si particles dispersed in the inactive matrix, the alloy ribbons were fabricated using the melt spinning process. The thin ribbons were pulverized using ball-milling to make a fine powder of ˜ 4 µm average size. Coin-cell assembly was carried out under an argon gas in a glove box, in which pure lithium was used as a counter-electrode. The cells were cycled using the galvanostatic method in the potential range of 0.01 V and 1.5 V vs. Li/Li+. The microstructure and morphology were examined using an x-ray diffractometer, Field-Emission Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy. Among the anode alloys, the Si70Ti15Ni15 electrodes had the highest discharge capacity (974.1 mAh/g) after the 50th cycle, and the Si60Ti16Ni16Cu8 electrode showed the best coulombic efficiency of ˜95.9% in cyclic behavior. It was revealed that the Si7Ni4Ti4 crystal phase coexisting with an amorphous phase, could more efficiently act as a buffer layer than the fully crystallized Si7Ni4Ti4 phase. Consequently, the electrochemical properties of the anode materials pronouncedly improved when the nano-sized primary Si particle was dispersed in the inactive Si7Ni4Ti4-based matrix mixed with an amorphous structure.

  3. Formulation development and in vitro evaluation of solidified self-microemulsion in the form of tablet containing atorvastatin calcium.

    Science.gov (United States)

    Ali, Kazi Asraf; Mukherjee, Biswajit; Bandyopadhyay, Amal Kumar

    2013-11-01

    The objective of our present study was to prepare solid self-microemulsion in the form of tablet of a poorly water soluble drug, Atorvastatin calcium (ATNC) to increase the solubility, dissolution rate, and minimize the hazards experienced from liquid emulsions. Self-microemulsifying ATNC tablet was formulated mainly by using self-emulsifying base, solidifying agent silicon dioxide and sodium starch glycolate as tablet disintegrant. Self-emulsifying base containing Transcutol P, Gelucire 44/14, and Lutrol F68 with their ratios in the formulation, were best selected by solubility study and ternary phase diagram in different vehicles. Particle size of microemulsion from tablet, physical parameters of the tablet and drug content has been checked. In vitro drug release rate has been carried out in phosphate buffer medium (pH 6.8). Physicochemical characterization of the drug in the optimized formulation has been performed to check drug-excipient incompatibility, if any. Average particle diameter of the emulsions formed from the tablet was found to be below 100 nm in case of formulation F4 and F5, which indicated microemulsions has been formed. In vitro drug release from the formulations F3, F4, and F5 was found to be >90%, indicated the enhancement of solubility of ATNC compared to parent drug. Differential thermal analysis (DTA), Powder X-ray Diffraction (X-RD) and Fourier transform infra red (FTIR) study proved the identity of the drug in the optimized formulation. The tablet form of self-microemulsifying (SME) drug delivery is good for solubility enhancement.

  4. Interconnection of thermal parameters, microstructure and mechanical properties in directionally solidified Sn–Sb lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Marcelino; Costa, Thiago [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Rocha, Otávio [Federal Institute of Education, Science and Technology of Pará — IFPA, 66093-020 Belém, PA (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos — UFSCar, 13565-905 São Carlos, SP (Brazil); Cheung, Noé, E-mail: cheung@fem.unicamp.br [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil)

    2015-08-15

    Considerable effort is being made to develop lead-free solders for assembling in environmental-conscious electronics, due to the inherent toxicity of Pb. The search for substitute alloys of Pb–Sn solders has increased in order to comply with different soldering purposes. The solder must not only meet the expected levels of electrical performance but may also have appropriate mechanical strength, with the absence of cracks in the solder joints. The Sn–Sb alloy system has a range of compositions that can be potentially included in the class of high temperature solders. This study aims to establish interrelations of solidification thermal parameters, microstructure and mechanical properties of Sn–Sb alloys (2 wt.%Sb and 5.5 wt.%Sb) samples, which were directionally solidified under cooling rates similar to those of reflow procedures in industrial practice. A complete high-cooling rate cellular growth is shown to be associated with the Sn–2.0 wt.%Sb alloy and a reverse dendrite-to-cell transition is observed for the Sn–5.5 wt.%Sb alloy. Strength and ductility of the Sn–2.0 wt.%Sb alloy are shown not to be affected by the cellular spacing. On the other hand, a considerable variation in these properties is associated with the cellular region of the Sn–5.5 wt.%Sb alloy casting. - Graphical abstract: Display Omitted - Highlights: • The microstructure of the Sn–2 wt.%Sb alloy is characterized by high-cooling rates cells. • Reverse dendrite > cell transition occurs for Sn–5.5 wt.%Sb alloy: cells prevail for cooling rates > 1.2 K/s. • Sn–5.5 wt.%Sb alloy: the dendritic region occurs for cooling rates < 0.9 K/s. • Sn–5.5 wt.%Sb alloy: tensile properties are improved with decreasing cellular spacing.

  5. Valence electron structure analysis of the cubic silicide intermetallics in rapidly solidified Al-Fe-V-Si alloy

    International Nuclear Information System (INIS)

    Wang, J.Q.; Qian, C.F.; Zhang, B.J.; Tseng, M.K.; Xiong, S.W.

    1996-01-01

    The application of rapid solidification for the development of elevated temperature aluminum alloys has resulted in the emergence of several alloys based on the Al-Fe alloy system. Of particular interest are Al-Fe-V-Si alloys which have excellent room temperature and high temperature mechanical properties. In a pioneering study, Skinner et al. showed the stabilization of the cubic phase in ternary Al-Fe-Si alloy by the addition of a quaternary element, vanadium. The evolution of the microstructure in these alloys both during rapid solidification and subsequent processing is of crucial importance. Kim has demonstrated that the composition of the silicide phase in rapidly solidified Al-Fe-V-Si alloy is very close to Al 12 (Fe,V) 3 Si with the body centered cubic (bcc) structure. The structure is closely related to that of quasicrystals.In view of the structural features and the relationship between the α 12 and α 13 phases, the researching emphasis should firstly be put on the α 12 phase. In this paper the authors analyzed the α -(AlFeSi)(α 12 -type) phase from the angle of atomic valence electron structure other than the traditional methods of obtaining the diffraction spots of the phase. Several pieces of information were obtained about the hybrid levels and bond natures of every kind of atom in the α -(AlFeSi) phase. Finally the authors explained the phenomenon which V atom can substitute for Fe atom in the α 12 phase and improve the thermal stability of the phase in Al-Fe-V-Si alloy

  6. Incorporating an extended dendritic growth model into the CAFE model for rapidly solidified non-dilute alloys

    International Nuclear Information System (INIS)

    Ma, Jie; Wang, Bo; Zhao, Shunli; Wu, Guangxin; Zhang, Jieyu; Yang, Zhiliang

    2016-01-01

    We have extended the dendritic growth model first proposed by Boettinger, Coriell and Trivedi (here termed EBCT) for microstructure simulations of rapidly solidified non-dilute alloys. The temperature-dependent distribution coefficient, obtained from calculations of phase equilibria, and the continuous growth model (CGM) were adopted in the present EBCT model to describe the solute trapping behaviors. The temperature dependence of the physical properties, which were not used in previous dendritic growth models, were also considered in the present EBCT model. These extensions allow the present EBCT model to be used for microstructure simulations of non-dilute alloys. The comparison of the present EBCT model with the BCT model proves that the considerations of the distribution coefficient and physical properties are necessary for microstructure simulations, especially for small particles with high undercoolings. Finally, the EBCT model was incorporated into the cellular automaton-finite element (CAFE) model to simulate microstructures of gas-atomized ASP30 high speed steel particles that were then compared with experimental results. Both the simulated and experimental results reveal that a columnar dendritic microstructure preferentially forms in small particles and an equiaxed microstructure forms otherwise. The applications of the present EBCT model provide a convenient way to predict the microstructure of non-dilute alloys. - Highlights: • A dendritic growth model was developed considering non-equilibrium distribution coefficient. • The physical properties with temperature dependence were considered in the extended model. • The extended model can be used to non-dilute alloys and the extensions are necessary in small particles. • Microstructure of ASP30 steel was investigated using the present model and verified by experiment.

  7. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material.

    Science.gov (United States)

    Gu, X N; Li, X L; Zhou, W R; Cheng, Y; Zheng, Y F

    2010-06-01

    Rapidly solidified (RS) Mg–3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s(-1), 30 m s(-1) and 45 m s(-1) with the as-cast Mg–3Ca alloy ingot as a raw material. The RS45 Mg–3Ca alloy ribbon showed a much more fine grain size feature (approximately 200–500 nm) in comparison to the coarse grain size (50–100 μm)of the original as-cast Mg–3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg–3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds(1.43 mm yr(-1) for RS15, 0.94 mm yr(-1) for RS30 and 0.36 mm yr(-1) for RS45). The RS Mg–3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg–3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg–3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells,whereas the as-cast Mg–3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg–3Ca alloy ribbons than that of the as-cast Mg–3Ca alloy ingot.

  8. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X N; Zhou, W R; Zheng, Y F [State Key Laboratory for Turbulence and Complex System and Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China); Li, X L [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Cheng, Y, E-mail: yfzheng@pku.edu.c [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)

    2010-06-01

    Rapidly solidified (RS) Mg-3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s{sup -1}, 30 m s{sup -1} and 45 m s{sup -1}) with the as-cast Mg-3Ca alloy ingot as a raw material. The RS45 Mg-3Ca alloy ribbon showed a much more fine grain size feature (approximately 200-500 nm) in comparison to the coarse grain size (50-100 {mu}m) of the original as-cast Mg-3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg-3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds (1.43 mm yr{sup -1} for RS15, 0.94 mm yr{sup -1} for RS30 and 0.36 mm yr{sup -1} for RS45). The RS Mg-3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg-3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg-3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells, whereas the as-cast Mg-3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg-3Ca alloy ribbons than that of the as-cast Mg-3Ca alloy ingot.

  9. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material

    International Nuclear Information System (INIS)

    Gu, X N; Zhou, W R; Zheng, Y F; Li, X L; Cheng, Y

    2010-01-01

    Rapidly solidified (RS) Mg-3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s -1 , 30 m s -1 and 45 m s -1 ) with the as-cast Mg-3Ca alloy ingot as a raw material. The RS45 Mg-3Ca alloy ribbon showed a much more fine grain size feature (approximately 200-500 nm) in comparison to the coarse grain size (50-100 μm) of the original as-cast Mg-3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg-3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds (1.43 mm yr -1 for RS15, 0.94 mm yr -1 for RS30 and 0.36 mm yr -1 for RS45). The RS Mg-3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg-3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg-3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells, whereas the as-cast Mg-3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg-3Ca alloy ribbons than that of the as-cast Mg-3Ca alloy ingot.

  10. Effect of a high magnetic field on the microstructures in directionally solidified Zn–Cu peritectic alloys

    International Nuclear Information System (INIS)

    Li, Xi; Gagnoud, Annie; Wang, Jiang; Li, Xiaolong; Fautrelle, Yves; Ren, Zhongming; Lu, Xionggang; Reinhart, Guillaume; Nguyen-Thi, Henri

    2014-01-01

    The effect of an axial high magnetic field on the microstructures in directionally solidified Zn–Cu peritectic alloys was investigated. The experimental results indicated that the magnetic field induced the destabilization of the liquid–solid interface and the formation of a band-like structure. The magnetic field also caused the disruption of the columnar η-Zn and ε-Zn 5 Cu dendrites. As the applied magnetic field increased, the columnar-to-equiaxed transition occurred, and the size of the equiaxed grains gradually decreased. The magnetic effects, the magnetic moment and the thermoelectric magnetic effects during the directional solidification of Zn–Cu peritectic alloys under an axial magnetic field were studied. Regular ε-Zn 5 Cu hexagons appeared on the transverse section of the sample fabricated with a high magnetic field (i.e. 16 T). In addition, electron backscatter diffraction analysis revealed that the 〈0 0 0 1〉-crystal direction of the Zn 5 Cu crystal is not only its easy magnetization direction but also its preferred growth direction. The thermoelectric magnetic effects were numerically simulated. The results indicated that a thermoelectric magnetic force acts on the solid near the liquid–solid interface and increases linearly with an increase in the magnetic field. As the effect of the magnetic moment arising from the magnetic crystalline anisotropy is eliminated, the thermoelectric magnetic effect has a substantial effect on the solidification structure. Therefore, the destabilization of the liquid–solid interface and the disruption of the dendrites during directional solidification under the magnetic field are primarily due to the thermoelectric magnetic force acting on the solid

  11. Incorporating an extended dendritic growth model into the CAFE model for rapidly solidified non-dilute alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Jie; Wang, Bo [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Zhao, Shunli [Research Institute, Baoshan Iron & Steel Co., Ltd, Shanghai 201900 (China); Wu, Guangxin [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Zhang, Jieyu, E-mail: zjy6162@staff.shu.edu.cn [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China); Yang, Zhiliang [State Key Laboratory of Advanced Special Steel, Shanghai University, Shanghai 200072 (China); Shanghai Engineering Technology Research Center of Special Casting, Shanghai 201605 (China)

    2016-05-25

    We have extended the dendritic growth model first proposed by Boettinger, Coriell and Trivedi (here termed EBCT) for microstructure simulations of rapidly solidified non-dilute alloys. The temperature-dependent distribution coefficient, obtained from calculations of phase equilibria, and the continuous growth model (CGM) were adopted in the present EBCT model to describe the solute trapping behaviors. The temperature dependence of the physical properties, which were not used in previous dendritic growth models, were also considered in the present EBCT model. These extensions allow the present EBCT model to be used for microstructure simulations of non-dilute alloys. The comparison of the present EBCT model with the BCT model proves that the considerations of the distribution coefficient and physical properties are necessary for microstructure simulations, especially for small particles with high undercoolings. Finally, the EBCT model was incorporated into the cellular automaton-finite element (CAFE) model to simulate microstructures of gas-atomized ASP30 high speed steel particles that were then compared with experimental results. Both the simulated and experimental results reveal that a columnar dendritic microstructure preferentially forms in small particles and an equiaxed microstructure forms otherwise. The applications of the present EBCT model provide a convenient way to predict the microstructure of non-dilute alloys. - Highlights: • A dendritic growth model was developed considering non-equilibrium distribution coefficient. • The physical properties with temperature dependence were considered in the extended model. • The extended model can be used to non-dilute alloys and the extensions are necessary in small particles. • Microstructure of ASP30 steel was investigated using the present model and verified by experiment.

  12. Study of Zr{sub x}Zn{sub 0.5−x}Ni{sub 0.5}Fe{sub 2}O{sub 4} 0≤x≤0.25: Synthesis, structural, magnetic and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Jasmeen; Kumar, Rupesh [Nanotechnology Research Centre, DAV Institute of Engineering and Technology, Jalandhar 144008 (India); Rajput, Jaspreet Kaur [Department of Chemistry, Dr. B.R. Ambedkar National Institute of Technology, Jalandhar 144011 (India); Kumar, Arvind [Department of Electronics and Communication, UIET, Panjab University, Chandigarh 160025 (India)

    2016-03-01

    Zirconium substituted zinc–nickel ferrite nanoparticles with chemical composition of Zr{sub x}Zn{sub 0.5−x}Ni{sub 0.5}Fe{sub 2}O{sub 4} (0≤x≤0.25) have been synthesized successfully by solution combustion method using high purity nitrates and fueling agent urea. Powder XRD study confirms the single phase formation of composite ferrite which belongs to cubic spinel structure. TEM further reveals the morphology of well dispersed Zn–Ni ferrite nanoparticles to be spherical. Effect of change of doping concentration of Zirconium is observed using FTIR. The saturation magnetization gradually decreases with the increase in Zr substitution and reaches minimum when x=0.25 whereas the coercivity value reaches minimum when x=0.15. DC electrical resistivity has been found to vary with increasing Zr content. The good electrical resistivity (>10{sup 7} Ωcm) qualify the ceramic for high frequency transformer applications. - Graphical abstract: Zr Doped Zn–Ni Ferrite nanoparticles. - Highlights: • Zr{sub x}Zn{sub 0.5-x}Ni{sub 0.5}Fe{sub 2}O{sub 4} nanoparticles were synthesized by solution combustion method. • Increase in doping concentration of Zirconium reduces the grain size of the nanoparticles. • Very low value of coercivity (0.73 Oe to 137.34 Oe) obtained for such particles indicates that the material is soft magnet. • High resistivity (90 MΩcm to 845 MΩcm) was obtained that qualified the material for high frequency and power supply transformers applications.

  13. Laachite, (Ca,Mn){sub 2}Zr{sub 2}Nb{sub 2}TiFeO{sub 14}, a new zirconolite-related mineral from the Eifel volcanic region, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Chukanov, Nikita V. [Institute of Problems of Chemical Physics, Chernogolovka (Russian Federation); Krivovichev, Sergey V.; Pakhomova, Anna S. [St. Petersburg State Univ. (Russian Federation). Faculty of Crystallography; Pekov, Igor V.; Vigasina, Marina F. [Moscow State Univ. (Russian Federation). Faculty of Geology; Schaefer, Christof [Suedwestdeutsche Salzwerke AG, Heilbronn (Germany); Van, Konstantin V. [Russian Academy of Sciences, Chernogolovka (Russian Federation). Inst. of Experimental Mineralogy

    2014-02-15

    The new mineral laachite was discovered in a sanidinite specimen from the Laach Lake (Laacher See) volcano, Eifel region, Rheinland-Pfalz, Germany. Associated minerals are sanidine, allanite-(Ce), baddeleyite, hau¨yne, hedenbergite, intermediate members of the jacobsite-magnetite series, phlogopite, rhodonite, spessartine, tephroite, thorite, zircon, and a pyrochlore-group mineral. Laachite is deep brownish-red, has an adamantine lustre, and is translucent; the streak is brownish red. It forms longprismatic crystals up to 0.02 x 0.04 x 0.5 mm, which are present as random intergrowths and twins in cavities within sanidinite. The density calculated from the empirical formula is 5.417 g/cm{sup 3}. The mean refractive index calculated from the Gladstone-Dale relationship is 2.26. The Raman spectrum shows the absence of hydrogen-bearing groups. The chemical composition is (electron microprobe, mean of 5 analyses, wt. %): CaO 4.29, MnO 9.42, FeO 5.73, Y{sub 2}O{sub 3} 2.56, La{sub 2}O{sub 3} 2.00, Ce{sub 2}O{sub 3} 6.37, Nd{sub 2}O{sub 3} 2.22, Al{sub 2}O{sub 3} 0.99, ThO{sub 2} 7.75, TiO{sub 2} 10.98, ZrO{sub 2} 19.39, Nb{sub 2}O{sub 5} 27.82, total 99.52. The empirical formula based on 14 O atoms is: (Ca{sub 0.66}Mn{sub 0.37}Th{sub 0.25}Y{sub 0.20}La{sub 0.11}Ce{sub 0.34}Nd{sub 0.11})(Zr{sub 1.3} {sub 6}Mn{sub 0.64})(Nb{sub 1.81}Ti{sub 1.19})(Fe{sub 0.69}Al{sub 0.17}Mn{sub 0.14})O{sub 14.00}. The simplified formula, taking into account the structural data, is: (Ca,Mn){sub 2}(Zr,Mn){sub 2}Nb{sub 2}TiFeO{sub 14}. Laachite is monoclinic, space group C2/c, a = 7.3119(5), b = 14.1790(10), c = 10.1700(7)Aa, β = 90.072(2), V = 1054.38(1) Aa{sup 3}, Z = 4. The crystal structure was solved using single-crystal X-ray diffraction data. Laachite is a monoclinic analogue of zirconolite-3O, CaZrTi{sub 2}O{sub 7}, with Nb dominant over Ti in the octahedral sites Nb1 and Nb2 and Fe dominant in a site with four-fold coordination. The strongest lines of the powder X-ray diffraction

  14. Directionally Solidified Multifunctional Ceramics

    Science.gov (United States)

    2006-12-01

    Vidrio , Vol. 44 [5] (2005) pp 347 - 352. 9. F. W. Dynys and A. Sayir, "Self Assemble Silicide Architectures by Directional Solidification," Journal...Sociedad Espanola de Ceramica y Vidrio , Vol. 43 [4] (2004) pp 753 - 758. 21. A. Sayir and F. S. Lowery, "Combustion-Resistance of Silicon-Based Ceramics...Espafiola de Cerdmica y Vidrio , Vol. 43 [3], 2004. ISSN-0366-3175-BSCVB9. 14 37. P. Berger, A. Sayir and M. H. Berger, "Nuclear Microprobe using Elastic

  15. Effect of Al substitution for Ga on the mechanical properties of directional solidified Fe-Ga alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yangyang; Li, Jiheng; Gao, Xuexu, E-mail: gaox@skl.ustb.edu.cn

    2017-02-01

    Alloys of Fe{sub 82}Ga{sub 18−x}Al{sub x} (x=0, 4.5, 6, 9, 12, 13.5) were prepared by directional solidification technique and exhibited a <001> preferred orientation along the axis of alloy rods. The saturation magnetostriction value of the Fe{sub 82}Ga{sub 13.5}Al{sub 4.5} alloy was 247 ppm under no pre-stress. The tensile properties of alloys of Fe{sub 82}Ga{sub 18−x}Al{sub x} at room temperature were investigated. The results showed that tensile ductility of binary Fe-Ga alloy was significantly improved with Al addition. The fracture elongation of the Fe{sub 82}Ga{sub 18} alloy was only 1.3%, while that of the Fe{sub 82}Ga{sub 9}Al{sub 9} alloy increased up to 16.5%. Addition of Al increased the strength of grain boundary and cleavage, resulting in the enhancement of tensile ductility of the Fe-Ga-Al alloys. Analysis of deformation microstructure showed that a great number of deformation twins formed in the Fe-Ga-Al alloys, which were thought to be the source of serrated yielding in the stress-strain curves. The effect of Al content in the Fe-Ga-Al alloys on tensile ductility was also studied by the analysis of deformation twins. It indicated that the joint effect of slip and twinning was beneficial to obtain the best ductility in the Fe{sub 82}Ga{sub 9}Al{sub 9} alloy. - Highlights: • Tensile ductility of directional solidified Fe-Ga alloys was significantly improved with Al addition. • The fracture elongation of binary Fe{sub 82}Ga{sub 18} alloy was only 1.3% at room temperature. • The fracture elongation of Fe{sub 82}Ga{sub 9}Al{sub 9} alloy was 16.5% at room temperature. • A great number of deformation twins formed in the Fe-Ga-Al alloys during tensile tests at room temperature.

  16. The potential of solidified molasses-based blocks for the correction of multinutritional deficiencies in buffaloes and other ruminants fed low-quality agro-industrial byproducts

    International Nuclear Information System (INIS)

    Leng, R.A.

    1984-01-01

    The main principles for formulating diets for ruminant animals in developing countries are outlined and examples provided of the successful application of these principles for feeding buffaloes and cattle in India, Philippines and Australia. It is concluded that the provision of a continuous supply of urea in the form of solidified feed blocks to increase the intake and digestibility of roughage-based diets is a management tool that could be used by small farmers in developing countries to improve weight gains and milk yields. Since such blocks can be easily supplemented with macro- and micro-elements needed by ruminants, they could also be useful for correcting multi-nutritional deficiencies. (author)

  17. Large magnetoresistance in a directionally solidified Ni44.5Co5.1Mn37.1In13.3 magnetic shape memory alloy

    Science.gov (United States)

    Li, Zongbin; Hu, Wei; Chen, Fenghua; Zhang, Mingang; Li, Zhenzhuang; Yang, Bo; Zhao, Xiang; Zuo, Liang

    2018-04-01

    Polycrystalline Ni44.5Co5.1Mn37.1In13.3 alloy with coarse columnar-shaped grains and 〈0 0 1〉A preferred orientation was prepared by directional solidification. Due to the strong magnetostructural coupling, inverse martensitic transformation can be induced by the magnetic field, resulting in large negative magnetoresistance up to -58% under the field of 3 T. Such significant field controlled functional behaviors should be attributed to the coarse grains and strong preferred orientation in the directionally solidified alloy.

  18. Removal of radioactive cesium from surface soils solidified using polyion complex. Rapid communication for decontamination test at Iitate-mura in Fukushima Prefecture

    International Nuclear Information System (INIS)

    Naganawa, Hirochika; Yanase, Nobuyuki; Mitamura, Hisayoshi; Nagano, Tetsushi; Yoshida, Zenko; Kumazawa, Noriyuki; Saitoh, Hiroshi; Kashima, Kaoru; Fukuda, Tatsuya; Tanaka, Shun-ichi

    2011-01-01

    We tried the decontamination of surface soils for three types of agricultural land at Nagadoro district of Iitate-mura (village) in Fukushima Prefecture, which is highly contaminated by deposits of radionuclides from the plume released from the Fukushima Daiichi nuclear power plant. The decontamination method consisted of the peeling of surface soils solidified using a polyion complex, which was formed from a salt solution of polycations and polyanions. Two types of polyion complex solution were applied to an upland field in a plastic greenhouse, a pasture, and a paddy field. The decontamination efficiency of the surface soils reached 90%, and dust release was effectively suppressed during the removal of surface soils. (author)

  19. Determination of performance criteria for high-level solidified nuclear waste from the commercial nuclear fuel cycle: a probabilistic safety analysis

    International Nuclear Information System (INIS)

    Heckman, R.A.

    1978-01-01

    To minimize the radiological risk from the operation of a waste management system for the safe disposal of high-level waste, performance characteristics of the solidified waste form must be specified. The minimum waste form characteristics that must be specified are the radionuclide volatilization fraction, airborne particulate dispersion fraction, and the aqueous dissolution characteristics. The results indicate that the pre-emplacement environs are more limiting in establishing the waste form performance criteria than the post-emplacement environs. The actual values of expected risk are sensitive to modeling assumptions and data base uncertainties. The transportation step appears to be the most limiting in determining the required performance characteristics

  20. An Abnormal Increase of Fatigue Life with Dwell Time during Creep-Fatigue Deformation for Directionally Solidified Ni-Based Superalloy DZ445

    Science.gov (United States)

    Ding, Biao; Ren, Weili; Deng, Kang; Li, Haitao; Liang, Yongchun

    2018-03-01

    The paper investigated the creep-fatigue behavior for directionally solidified nickel-based superalloy DZ445 at 900 °C. It is found that the fatigue life shows an abnormal increase when the dwell time exceeds a critical value during creep-fatigue deformation. The area of hysteresis loop and fractograph explain the phenomenon quite well. The shortest life corresponds to the maximal area of hysteresis loop, i. e. the maximum energy to be consumed during the creep-fatigue cycle. The fractographic observation of failed samples further supports the abnormal behavior of fatigue life.

  1. Phase formation kinetics, hardness and magnetocaloric effect of sub-rapidly solidified LaFe11.6Si1.4 plates during isothermal annealing

    Science.gov (United States)

    Dai, Yuting; Xu, Zhishuai; Luo, Zhiping; Han, Ke; Zhai, Qijie; Zheng, Hongxing

    2018-05-01

    High-temperature phase transition behavior and intrinsic brittleness of NaZn13-type τ1 phase in La-Fe-Si magnetocaloric materials are two key problems from the viewpoint of materials production and practical applications. In the present work, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation was introduced to quantitatively characterize the formation kinetics of τ1 phase in sub-rapidly solidified LaFe11.6Si1.4 plates during the isothermal annealing process. Avrami index was estimated to be 0.43 (∼0.5), which suggests that the formation of τ1 phase is in a diffusion-controlled one-dimensional growth mode. Meanwhile, it is found that the Vickers hardness as a function of annealing time for sub-rapidly solidified plates also agrees well with the JMAK equation. The Vickers hardness of τ1 phase was estimated to be about 754. Under a magnetic field change of 30 kOe, the maximum magnetic entropy change was about 22.31 J/(kg·K) for plates annealed at 1323 K for 48 h, and the effective magnetic refrigeration capacity reached 191 J/kg.

  2. Formation of an 18R long-period stacking ordered structure in rapidly solidified Mg88Y8Zn4 alloy

    International Nuclear Information System (INIS)

    Garcés, Gerardo; Requena, Guillermo; Tolnai, Domonkos; Pérez, Pablo; Medina, Judit; Stark, Andreas; Schell, Norbert; Adeva, Paloma

    2016-01-01

    The formation of the long-period stacking ordered structure (LPSO) in a Mg 88 Y 8 Zn 4 (at%) ribbon produced by melt spinning was studied using high energy X-ray synchrotron radiation diffraction during in-situ isochronal heating and transmission electron microscopy. The microstructure of the rapidly solidified ribbons is characterised by fine magnesium grains with yttrium and zinc in solid solution and primary 18R LPSO-phase segregated at grain boundaries. Using differential scanning calorimetry, a strong exothermal peak was observed around 300 °C which was associated with the development of the 18R-type LPSO-phase in the magnesium grains. The apparent activation energy calculated using the Kissinger model was 125 KJmol −1 and it is related to simultaneous diffusion of Y and Zn through magnesium basal plane. - Highlights: •The formation of the LPSO phase in rapidly solidified ribbons was studied. •The formation of the 18R LPSO starts at around 300 °C. •LPSO formation have to steps: Stacking faults along basal plane and then growth of 18R structure along the c direction.

  3. Numerical Research on Magnetic Field, Temperature Field and Flow Field During Melting and Directionally Solidifying TiAl Alloys by Electromagnetic Cold Crucible

    Science.gov (United States)

    Chen, Ruirun; Yang, Yaohua; Gong, Xue; Guo, Jingjie; Su, Yanqing; Ding, Hongsheng; Fu, Hengzhi

    2017-12-01

    The electromagnetic cold crucible (EMCC) technique is an effective method to melt and directionally solidify reactive and high-temperature materials without contamination. The temperature field and fluid flow induced by the electromagnetic field are very important for melting and controlling the microstructure. In this article, a 3D EMCC model for calculating the magnetic field in the charges (TiAl alloys) using the T-Ω finite element method was established and verified. Magnetic fields in the charge under different electrical parameters, positions and dimensions of the charge were calculated and analyzed. The calculated results show that the magnetic field concentrates in the skin layer, and the magnetic flux density ( B) increases with increasing of the frequency, charge diameter and current. The maximum B in the charge is affected by the position of the charge in EMCC ( h 1) and the charge height ( h 2), which emerges at the middle of coils ( h c) when the relationship of h c < h 1 + h 2 < h c + δ is satisfied. Lower frequency and smaller charge diameter can improve the uniformity of the magnetic field in the charge. Consequently, the induced uniform electromagnetic stirring weakens the turbulence and improves temperature uniformity in the vicinity of the solid/liquid (S/L) interface, which is beneficial to forming a planar S/L interface during directional solidification. Based on the above conclusions, the TiAlNb alloy was successfully melted with lower power consumption and directionally solidified by the square EMCC.

  4. NWTS program criteria for mined geologic disposal of nuclear waste: functional requirements and performance criteria for waste packages for solidified high-level waste and spent fuel

    International Nuclear Information System (INIS)

    1982-07-01

    The Department of Energy (DOE) has primary federal responsibility for the development and implementation of safe and environmentally acceptable nuclear waste disposal methods. Currently, the principal emphasis in the program is on emplacement of nuclear wastes in mined geologic repositories well beneath the earth's surface. A brief description of the mined geologic disposal system is provided. The National Waste Terminal Storage (NWTS) program was established under DOE's predecessor, the Energy Research and Development Administration, to provide facilities for the mined geologic disposal of radioactive wastes. The NWTS program includes both the development and the implementation of the technology necessary for designing, constructing, licensing, and operating repositories. The program does not include the management of processing radioactive wastes or of transporting the wastes to repositories. The NWTS-33 series, of which this document is a part, provides guidance for the NWTS program in the development and implementation of licensed mined geologic disposal systems for solidified high-level and transuranic (TRU) wastes. This document presents the functional requirements and performance criteria for waste packages for solidified high-level waste and spent fuel. A separate document to be developed, NWTS-33(4b), will present the requirements and criteria for waste packages for TRU wastes. The hierarchy and application of these requirements and criteria are discussed in Section 2.2

  5. Effect of pH on the release of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resins collected from operating nuclear power stations

    International Nuclear Information System (INIS)

    McIsaac, C.V.; Akers, D.W.; McConnell, J.W.

    1991-06-01

    Data are presented on the physical stability and leachability of radionuclides and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from two operating commercial light water reactors. Small-scale waste--form specimens collected during solidifications performed at the Brunswick Steam Electric Plant Unit 1 and at the James A. FitzPatrick Nuclear Power Station were leach-tested and subjected to compressive strength testing in accordance with the Nuclear Regulatory Commission's ''Technical Position on Waste Form'' (Revision 1). Samples of untreated resin waste collected from each solidification vessel before the solidification process were analyzed for concentrations of radionuclides, selected transition metals, and chelating agents to determine the quantities of these chemicals in the waste-form specimens. The chelating agents included oxalic, citric, and picolinic acids. In order to determine the effect of leachant chemical composition and pH on the stability and leachability of the waste forms, waste-form specimens were leached in various leachants. Results of this study indicate that differences in pH do not affect releases from cement-solidified decontamination ion-exchange resin waste forms, but that differences in leachant chemistry and the presence of chelating agents may affect the releases of radionuclides and chelating agents. Also, this study indicates that the cumulative releases of radionuclides and chelating agents are similar for waste- form specimens that decomposed and those that retained their general physical form. 36 refs., 60 figs., 28 tabs

  6. Influence of Thermal Parameters, Microstructure, and Morphology of Si on Machinability of an Al–7.0 wt.% Si Alloy Directionally Solidified

    Directory of Open Access Journals (Sweden)

    Cássio A. P. Silva

    2018-01-01

    Full Text Available This study aims to correlate the influence of thermal and microstructural parameters such as growth rate and cooling rate (VL and TR and secondary dendrite spacing (λ2, respectively, in the machining cutting temperature and tool wear on the necking process of the Al–7 wt.% Si alloy solidified in a horizontal directional device using a high-speed steel with a tungsten tool. The dependence of λ2 on VL and TR and dependence of the maximum cutting temperature and maximum flank wear on λ2 were determined by power experimental laws given by λ2 = constant (VL and TRn and TMAX, VBMAX = constant (λ2n, respectively. The maximum cutting temperature increased with increasing of λ2. The opposite occurred with the maximum flank wear. The role of Si alloying element on the aforementioned results has also been analyzed. A morphological change of Si along the solidified ingot length has been observed, that is, the morphology of Si in the eutectic matrix has indicated a transition from particles to fibers along the casting together with an increase of the particle diameters with the position from the metal/mold interface.

  7. Electrochemical detection of volatile organic compounds using a Na{sub 3}Zr{sub 2}Si{sub 2}PO{sub 12}/Bi{sub 2}Cu{sub 0.1}V{sub 0.9}O{sub 5.35} heterojunction device

    Energy Technology Data Exchange (ETDEWEB)

    Kida, Tetsuya, E-mail: kida@mm.kyushu-u.ac.jp [Department of Energy and Material Sciences, Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Morinaga, Naoki; Kishi, Shotaro [Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kasuga-Koen 6-1, Kasuga, Fukuoka 816-8580 (Japan); An, Ki-Mun; Sim, Kyoung-Won; Chae, Bu-Young [Department of Materials Science and Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Kim, Jung-kwan [Education Center for Green Industry-friendly Fusion Technology (GIFT), Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Ryu, Bong-Ki [Department of Materials Science and Engineering, Pusan National University, 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Shimanoe, Kengo [Department of Energy and Material Sciences, Faculty of Engineering Sciences, Kyushu University, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)

    2011-09-01

    Highlights: > A device combining a sodium ion conductor of NASICON (Na{sub 3}Zr{sub 2}Si{sub 2}PO{sub 12}) with an oxygen ion conductor of BiCuVOx (Bi{sub 2}Cu{sub 0.1}V{sub 0.9}O{sub 5.35}) was fabricated. > The device can electrochemically detect volatile organic compounds (VOCs). > The electrochemical oxidation of VOCs with oxide ions occurred as the sensing reaction. > The formation of an oxygen ion-conductive layer at the interface between NASICON and BiCuVOx was suggested. - Abstract: A fast sodium ion conductor, NASICON (Na{sub 3}Zr{sub 2}Si{sub 2}PO{sub 12}), has been widely used for gas sensor applications. In this study, we demonstrate that a device combining NASICON with an oxygen-ion conductor of BiCuVOx (Bi{sub 2}Cu{sub 0.1}V{sub 0.9}O{sub 5.35}) can electrochemically detect volatile organic compounds (VOCs), such as ethanol, formaldehyde, and toluene. The sensing electrode made of BiCuVOx was attached onto a sintered NASICON disk at high temperature to produce an interfacial layer that had a different morphology and composition from those of NASICON and BiCuVOx, as observed by scanning electron microscopy-energy dispersive X-ray spectroscopy analysis. The device in which NASICON was fitted with the BiCuVOx-based electrode was found to efficiently detect VOCs in ppm concentrations. The sensor signal (electromotive force) exceeded 100 mV in response to 10 ppm HCOH at 400 deg. C, demonstrating the high sensitivity of the device. It also exhibited a relatively quick response, reproducible and stable sensor signals, and high selectivity to VOCs. The sensor responses followed behavior typical for mixed-potential-type gas sensors based on oxygen-ion conductors. It was thus suggested that the electrochemical oxidation of VOCs with oxide ions took place at the interfacial oxygen ion-conductive layer that was formed by the reaction of NASICON with BiCuVOx.

  8. Evolution of the microstructure and hardness of a rapidly solidified/melt-spun AZ91 alloy upon aging at different temperatures

    International Nuclear Information System (INIS)

    Wang Baishu; Liu Yongbing; An Jian; Li Rongguang; Su Zhenguo; Su Guihua; Lu You; Cao Zhanyi

    2009-01-01

    The effect of aging at different temperatures on a rapidly solidified/melt-spun AZ91 alloy has been investigated in depth. The microstructures of as-spun and aged ribbons with a thickness of approximately 60 μm were characterized using X-ray diffraction, transmission electron microscopy and laser optical microscopy; microhardness measurements were also conducted. It was found that the commercial AZ91 alloy undergoes a cellular/dendritic transition during melt-spinning at a speed of 34 m/s. A strengthening effect due to aging was observed: a maximum hardness of 110 HV/0.05 and an age-hardenability of 50% were obtained when the ribbon was aged at 200 deg. C for 20 min. The β-Mg 17 Al 12 phase exhibits net and dispersion types of distribution during precipitation. The dispersion of precipitates in dendritic grains or cells is the main source of strengthening

  9. Effect of swaging on the 1000 C compressive slow plastic flow characteristics of the directionally solidified eutectic alloy gamma/gamma prime-alpha

    Science.gov (United States)

    Whittenberger, J. D.; Wirth, G.

    1983-01-01

    Swaging between 750 and 1050 C has been investigated as a means to introduce work into the directionally solidified eutectic alloy gamma/gamma prime-alpha (Ni-32.3 wt percent Mo-6.3 wt percent Al) and increase the elevated temperature creep strength. The 1000 C slow plastic compressive flow stress-strain rate properties in air of as-grown, annealed, and worked nominally 10 and 25 percent materials have been determined. Swaging did not improve the slow plastic behavior. In fact large reductions tended to degrade the strength and produced a change in the deformation mechanism from uniform flow to one involving intense slip band formation. Comparison of 1000 C tensile and compressive strength-strain rate data reveals that deformation is independent of the stress state.

  10. Determination of the leaching rate of radionuclide 134Cs from the solidified radioactive wastes in Syrian Portland cement and cement-microsilica matrixes

    International Nuclear Information System (INIS)

    Ismail Shaaban; Nasim Assi

    2010-01-01

    The suitability of Syrian Portland cement for disposal of solidified low-level radioactive waste was assessed by measuring the leaching rate of 134 Cs. In ordinary cement concrete, a leaching rate of 1.309 x 10 -3 g/cm 2 per day was measured. Mixing this concrete with microsilica reduced significantly the leaching rate to 3.106 x 10 -4 g/cm 2 per day for 1% mixing, and to 9.645 x 10 -5 g/cm 2 per day for 3% mixing. It was also found that the application of a latex paint reduced these leaching rates by about 10%. These results, along with mechanical strength tests (under radiation exposure, high temperature, long water immersion and freeze-thaw cycling) indicate that Syrian Portland cement is suited for the disposal of low-level radioactive waste. (author)

  11. Effect of Bi-content on hardness and micro-creep behavior of Sn-3.5Ag rapidly solidified alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, M. [Metal Physics Laboratory, Faculty of Science, Mansoura University (Egypt); Gouda, El Said [Metal Physics Laboratory, Department of Solid State Physics, Physics Division, National Research Center, Dokki, Giza (Egypt); Marei, L.K. [Faculty of Petroleum and Mining Engineering, Suez Canal University, Suez (Egypt)

    2009-12-15

    In the present paper, the influence of 1, 3, 5 and 10 % Bi (weight %) as ternary additions on structure, melting and mechanical properties of rapidly solidified Sn-3.5Ag alloy has been investigated. The effect of Bi was discussed based on the experimental results. The experimental results showed that the alloys of Sn-3.5Ag, Sn-3.5Ag-1Bi and Sn-3.5Ag-3Bi are composed of two phases; Ag{sub 3}Sn IMC embedded in Sn matrix phase, which indicated that the solubility of Bi phase in Sn-matrix was extended to 3 % as a result of rapid solidification. Bi precipitation in Sn matrix was only observed in Sn-3.5Ag-5Bi and Sn-3.5Ag-10Bi alloys. Also, addition of Bi decreased continuously the melting point of the eutectic Sn-3.5Ag alloy to 202.6 C at 10 % Bi. Vickers hardness of Sn-3.5Ag rapidly solidified alloy increased with increasing Bi content up to 3 % due to supersaturated solid solution strengthening hardening mechanism of Bi phase in Sn matrix, while the alloys contain 5 and 10 % Bi exhibited lower values of Vickers hardness. The lower values can be attributed to the precipitation of Bi as a secondary phase which may form strained regions due to the embrittlement of Bi atom. In addition, the effect of Bi addition on the micro-creep behavior of Sn-3.5Ag alloy as well as the creep rate have been described and has been calculated at room temperature. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Sahin, Cigdem Arpa; Tokgoez, Ilknur

    2010-01-01

    A rapid, simple and cost effective solidified floating organic drop microextraction (SFODME) and flow injection flame atomic absorption spectrometric determination (FI-FAAS) method for copper was developed. In this method, a free microdrop of 1-undecanol containing 1,5-diphenyl carbazide (DPC) as the complexing agent was transferred to the surface of an aqueous sample including Cu(II) ions, while being agitated by a stirring bar in the bulk of the solution. Under the proper stirring conditions, the suspended microdrop can remain at the top-center position of the aqueous sample. After the completion of the extraction, the sample vial was cooled by placing it in a refrigerator for 10 min. The solidified microdrop was then transferred into a conical vial, where it melted immediately and diluted to 300 μL with ethanol. Finally, copper ions in 200 μL of diluted solution were determined by FI-FAAS. Several factors affecting the microextraction efficiency, such as type of extraction solvent, pH, complexing agent concentration, extraction time, stirring rate, sample volume and temperature were investigated and optimized. Under optimized conditions for 100 mL of solution, the preconcentration factor was 333 and the enrichment factor was 324. The limit of detection (3 s) was 0.4 ng mL -1 , the limit of quantification (10 s) was 1.1 ng mL -1 and the relative standard deviation (RSD) for 10 replicate measurements of 10 ng mL -1 copper was 0.9%. The proposed method was successfully applied to the determination of copper in different water samples.

  13. Effect of cooling rate and Mg addition on the structural evaluation of rapidly solidified Al-20wt%Cu-12wt%Fe alloy

    Energy Technology Data Exchange (ETDEWEB)

    Karaköse, Ercan, E-mail: ekarakose@karatekin.edu.tr [Çankırı Karatekin University, Faculty of Sciences, Department of Physics, 18100 Çankırı (Turkey); Çolak, Hakan [Çankırı Karatekin University, Faculty of Sciences, Department of Chemistry, 18100 Çankırı (Turkey)

    2016-11-15

    The present work examines the effect of Mg contents and cooling rate on the morphology and mechanical properties of Al{sub 20}Cu{sub 12}Fe quasicrystalline alloy. The microstructure of the alloys was analyzed by scanning electron microscopy and the phase composition was identified by X-ray diffractometry. The melting characteristics were studied by differential thermal analysis under an Ar atmosphere. The mechanical features of the melt-spun and conventionally solidified alloys were tested by tensile-strength test and Vickers micro-hardness test. It was found that the final microstructure of the Al{sub 20}Cu{sub 12}Fe samples mainly depends on the cooling rate and Mg contents, which suggests that different cooling rates and Mg contents produce different microstructures and properties. The average grain sizes of the melt spun samples were about 100–300 nm at 35 m/s. The nanosize, dispersed, different shaped quasicrystal particles possessed a remarkable effect to the mechanical characteristics of the rapidly solidified ribbons. The microhardness values of the melt spun samples were approximately 18% higher than those of the conventionally counterparts. - Highlights: •Quasicrystal-creating materials have high potential for applications. •Different shaped nanosize quasicrystal particles were observed. •The addition of Mg has an important impact on the mechanical properties. •H{sub V} values of the MS0, MS3 and MS5 samples at 35 m/s were 8.56, 8.66 and 8.80 GPa. •The volume fraction of IQC increases with increasing cooling rates.

  14. Effects of Microalloying on the Microstructures and Mechanical Properties of Directionally Solidified Ni-33(at.%)Al-31Cr-3Mo Eutectic Alloys Investigated

    Science.gov (United States)

    Whittenberger, J. Daniel; Raj, Sai V.; Locci, Ivan E.; Salem, Jonathan A.

    2002-01-01

    Despite nickel aluminide (NiAl) alloys' attractive combination of oxidation and thermophysical properties, their development as replacements for superalloy airfoils in gas turbine engines has been largely limited by difficulties in developing alloys with an optimum combination of elevated-temperature creep resistance and room-temperature fracture toughness. Alternatively, research has focused on developing directionally solidified NiAl-based in situ eutectic composites composed of NiAl and (Cr,Mo) phases in order to obtain a desirable combination of properties a systematic investigation was undertaken at the NASA Glenn Research Center to examine the effects of small additions of 11 alloying elements (Co, Cu, Fe, Hf, Mn, Nb, Re, Si, Ta, Ti, and Zr) in amounts varying from 0.25 to 1.0 at.% on the elevated-temperature strength and room-temperature fracture toughness of directionally solidified Ni-33Al-31Cr-3Mo eutectic alloy. The alloys were grown at 12.7 mm/hr, where the unalloyed eutectic base alloy exhibited a planar eutectic microstructure. The different microstructures that formed because of these fifth-element additions are included in the table. The additions of these elements even in small amounts resulted in the formation of cellular microstructures, and in some cases, dendrites and third phases were observed. Most of these elemental additions did not improve either the elevated-temperature strength or the room-temperature fracture toughness over that of the base alloy. However, small improvements in the compression strength were observed between 1200 and 1400 K when 0.5 at.% Hf and 0.25 at.% Ti were added to the base alloy. The results of this study suggest that the microalloying of Ni-33Al-31Cr-3Mo will not significantly improve either its elevatedtemperature strength or its room-temperature fracture toughness. Thus, any improvements in these properties must be acquired by changing the processing conditions.

  15. Influence of the microstructure on the magnetic properties of Fe{sub 86}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5} alloy in the states following solidification and following short-duration annealing below the crystallization temperature

    Energy Technology Data Exchange (ETDEWEB)

    Gondro, Joanna, E-mail: j.gondro@wp.pl

    2017-06-15

    Highlights: • The samples prepared, in the form of ribbons, using a rapid-cooling method. • Amorphous ribbon of the alloy, of nominal composition Fe{sub 86}Zr{sub 7}Nb{sub 1}Cu{sub 1}B{sub 5}. • The amorphous structure was confirmed using XRD, Mössbauer spectroscopy and the microstructure of the specimens were observed with the use of high resolution transmission electron microscopy. • The magnetic properties of the samples were determined by analysis of initial magnetization curves. - Abstract: This paper investigates the influence of heat treatment on the magnetic properties of alloy samples prepared, in the form of ribbons, using a rapid-cooling method. The adopted isothermal annealing processes were found to lead: to the homogenization of the composition, to relaxation of the structure in the amorphous state, and to nanocrystallization. It has been shown that structural relaxation, occurring within the volume of the tested samples, exerts a large influence on the magnetic properties. Observed changes in the distribution of the induction hyperfine field at the {sup 57}Fe nuclei represent direct proof that chemical and topological disorder exists within the volume of the alloy, and the annealing process reduces the internal energy of the entire system. Considering the random anisotropy model for nanocrystalline materials, it can be concluded that the factor that increases, for example, the saturation magnetization is an increase in strength of exchange interactions, which is a measure of the ferromagnetic correlation interactions.

  16. Double-ceramic-layer thermal barrier coatings based on La{sub 2}(Zr{sub 0.7}Ce{sub 0.3}){sub 2}O{sub 7}/La{sub 2}Ce{sub 2}O{sub 7} deposited by electron beam-physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z.H. [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); He, L.M., E-mail: he_limin@yahoo.com [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Mu, R.D.; He, S.M.; Huang, G.H. [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao, X.Q., E-mail: xcao@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2010-03-15

    Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La{sub 2}(Zr{sub 0.7}Ce{sub 0.3}){sub 2}O{sub 7} (LZ7C3) and La{sub 2}Ce{sub 2}O{sub 7} (LC) were deposited by electron beam-physical vapor deposition (EB-PVD). The composition, interdiffusion, surface and cross-sectional morphologies, cyclic oxidation behavior of DCL coating were studied. Energy dispersive spectroscopy and X-ray diffraction analyses indicate that both LZ7C3 and LC coatings are effectively fabricated by a single LZ7C3 ingot with properly controlling the deposition energy. The chemical compatibility of LC coating and thermally grown oxide (TGO) layer is unstable. LaAlO{sub 3} is formed due to the chemical reaction between LC and Al{sub 2}O{sub 3} which is the main composition of TGO layer. Additionally, the thermal cycling behavior of DCL coating is influenced by the interdiffusion of Zr and Ce between LZ7C3 and LC coatings. The failure of DCL coating is a result of the sintering of LZ7C3 coating surface, the chemical incompatibility of LC coating and TGO layer and the abnormal oxidation of bond coat. Since no single material that has been studied so far satisfies all the requirements for high temperature applications, DCL coating is an important development direction of TBCs.

  17. Multiferroic and magnetoelectric properties of Ba{sub 0.85}Ca{sub 0.15}Zr{sub 0.1}Ti{sub 0.9}O{sub 3}–CoFe{sub 2}O{sub 4} core–shell nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Ajith S; Lekha, C.S. Chitra; Vivek, S. [Department of Physics, Central University of Kerala, Kasaragod 671314 (India); Saravanan, Venkata [Department of Physics, Central University of Tamil Nadu, Thiruvarur 610101 (India); Nandakumar, K. [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam 686560 (India); Nair, Swapna S., E-mail: swapna.s.nair@gmail.com [Department of Physics, Central University of Kerala, Kasaragod 671314 (India)

    2016-11-15

    Lead-free magnetoelectric (ME) composites with remarkable ME coupling are required for the realization of eco-friendly multifunctional devices. This work demonstrates the ME properties of Ba{sub 0.85}Ca{sub 0.15}Zr{sub 0.1}Ti{sub 0.9}O{sub 3}–CoFe{sub 2}O{sub 4} (BCZT–CFO) core–shell composites synthesized via co-sol–gel technique. Room temperature ferroelectric and ferromagnetic characterization have shown that the samples are magnetic and ferroelectric along with an adequate magnetoelectric coupling of 12.15 mV/(cm Oe). The strong dependence of electric parameters on applied magnetic DC bias fields demonstrated in ferroelectric and magnetoelectric measurements provide a framework for the development of potential magnetoelectric devices. Also, the high sensitivity of magnetoelectric coupling towards the applied AC magnetic field can be used for its application in magnetoelectric sensors. - Highlights: • The magnetoelectric multiferroic BCZT–CFO nanocomposite is synthesized via sol–gel route. • The XRD measurements show no phases other than BCZT and CFO. • The microstructure analysis employing TEM indicates that the majority of particles formed are having core–shell structure. • The capacitance, resistance and ferroelectric polarization are magnetically tunable. • The composite showed a high magnetoelectric response.

  18. High charge-discharge performance of Pb{sub 0.98}La{sub 0.02}(Zr{sub 0.35}Sn{sub 0.55}Ti{sub 0.10}){sub 0.995}O{sub 3} antiferroelectric ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Chenhong [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Liu, Zhen; Chen, Xuefeng; Yan, Shiguang; Cao, Fei; Dong, Xianlin; Wang, Genshui, E-mail: genshuiwang@mail.sic.ac.cn [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2016-08-21

    The energy storage performance and charge-discharge properties of Pb{sub 0.98}La{sub 0.02}(Zr{sub 0.35}Sn{sub 0.55}Ti{sub 0.10}){sub 0.995}O{sub 3} (PLZST) antiferroelectric ceramics were investigated through directly measuring the hysteresis loops and pulse discharge current-time curves. The energy density only varies 0.2% per degree from 25 °C to 85 °C, and the energy efficiency maintains at about 90%. Furthermore, an approximate calculating model of maximum power density p{sub max} was established for the discharge process. Under a relatively high working electric field (8.2 kV/mm), this ceramics possess a greatly enhanced power density of 18 MW/cm{sup 3}. Moreover, the pulse power properties did not show degradation until 1500 times of charge-discharge cycling. The large released energy density, high energy efficiency, good temperature stability, greatly enhanced power density, and excellent fatigue endurance combined together make this PLZST ceramics an ideal candidate for pulse power applications.

  19. The intermediate phase and low wave number phonon modes in antiferroelectric (Pb{sub 0.97}La{sub 0.02}) (Zr{sub 0.60}Sn{sub 0.40−y}Ti{sub y})O{sub 3} ceramics discovered from temperature dependent Raman spectra

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xiaojuan; Guo, Shuang [Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Hu, Zhigao, E-mail: zghu@ee.ecnu.edu.cn [Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Chen, Xuefeng; Wang, Genshui [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China); Dong, Xianlin; Chu, Junhao [Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China)

    2016-05-15

    Optical phonons and phase transitions of (Pb{sub 0.97}La{sub 0.02}) (Zr{sub 0.60}Sn{sub 0.40−y}Ti{sub y})O{sub 3} (PLZST 97/2/60/40-100y/100y) ceramics with different compositions have been investigated by x-ray diffraction and temperature dependent Raman spectra. From the temperature dependence of low wavenumber phonon modes, two phase transitions (antiferroelectric orthorhombic to intermediate phase and intermediate phase to paraelectric cubic phase) were detected. The intermediate phase could be the coexistence one of antiferroelectric orthorhombic and ferroelectric rhombohedral phase. In addition, two modes (a soft mode and an anharmonic hopping central mode) were found in the high temperature paraelectric cubic phase. On cooling, the anharmonic hopping central mode splits into two modes in the terahertz range. Moreover, the antiferrodistortive mode appears in the antiferroelectric orthorhombic phase. Based on the analysis, the phase diagram of PLZST ceramics can be well improved. - Highlights: • The evolution of phonon modes in antiferroelectric PLZST ceramics. • An intermediate phase was found between orthorhombic and cubic phase. • The phase diagram of PLZST ceramics can be well improved.

  20. Thermotropic phase transitions in Pb{sub 1−x}Sr{sub x}(Al{sub 1/3}Nb{sub 2/3}){sub 0.1}(Zr{sub 0.52}Ti{sub 0.48}){sub 0.9}O{sub 3} ceramics: Temperature dependent dielectric permittivity and Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Li, C. Q.; Peng, L.; Jiang, K.; Hu, Z. G., E-mail: zghu@ee.ecnu.edu.cn; Chu, J. H. [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Wang, P.; Liu, A. Y. [Department of Physics, Shanghai Normal University, Shanghai 200234 (China)

    2015-06-15

    The phase transitions of Pb{sub 1−x}Sr{sub x}(Al{sub 1/3}Nb{sub 2/3}){sub 0.1}(Zr{sub 0.52}Ti{sub 0.48}){sub 0.9}O{sub 3} (Sr-modified PAN-PZT) ceramics with Sr compositions of x = 2%, 5%, 10% and 15% have been investigated using X-ray diffraction (XRD), temperature dependent dielectric permittivity and Raman scattering. The XRD analysis show that the phase transition occurs between Sr composition of 5% and 10%. Based on the broad dielectric peaks at 100 Hz, the diffused phase transition from tetragonal (T) to cubic (C) structure shifts to lower temperature with increasing Sr composition. The dramatic changes of wavenumber and full width at half-maximum (FWHM) for E(TO{sub 4})′ softing mode can be observed at morphotropic phase boundary (MPB). Moreover, the MPB characteristic shows a wider and lower trend of temperature region with increasing Sr composition. It could be ascribed to the diminishment of the energy barrier and increment of A-cation entropy. Therefore, the Sr-modified PAN-PZT ceramics unambiguously undergo two successive structural transitions (rhombohedral-tetragonal-cubic phase) with temperature from 80 to 750 K. Correspondingly, the phase diagram of Sr-modified PAN-PZT ceramics can be well depicted.

  1. Study of the mechanical and magnetic properties of Fe{sub 61}Co{sub 10}Zr{sub 5-x}Hf{sub x}W{sub 2}Y{sub 2}B{sub 20} (x = 0 or 3) bulk amorphous and crystalline alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nabialek, Marcin G. [Institute of Physics, Czestochowa University of Technology, 19 Armii Krajowej Av., 42-200 Czestochowa (Poland); Szota, Michal [Institute of Materials Engineering, Czestochowa University of Technology, 19 Armii Krajowej Av., 42-200 Czestochowa (Poland); Dospial, Marcin J.

    2010-05-15

    The microstructure, thermal stability, mechanical and magnetic properties of Fe{sub 61}Co{sub 10}Zr{sub 5-x}Hf{sub x}W{sub 2}Y{sub 2}B{sub 20} (where x = 0 or 3) bulk metallic glasses (BMG) and their crystalline equivalents were investigated. The crystalline materials were smelted on a copper mould using an electric arc; their amorphous equivalents were prepared using the induction suction casting method (ISC). All samples investigated were in the form of plates with dimensions of 10x10x0.5mm. From X-ray diffraction and Moessbauer spectroscopy, it was found that both investigated alloys prepared using this method have an amorphous structure. From magnetic measurements obtained by a vibrating sample magnetometer (VSM), it was shown that all measured samples displayed soft magnetic properties with relatively high saturation of the magnetization. The thermal stability and glass-forming ability (GFA) for investigated alloys were derived from differential scanning calorimetry (DSC) curves. The measurements of mechanical properties for amorphous alloys were found to be better than those for crystalline alloys with the same atomic composition. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. The measurement of 129I for the cement and the paraffin solidified low and intermediate level wastes (LILWs), spent resin or evaporated bottom from the pressurized water reactor (PWR) nuclear power plants.

    Science.gov (United States)

    Park, S D; Kim, J S; Han, S H; Ha, Y K; Song, K S; Jee, K Y

    2009-09-01

    In this paper a relatively simple and low cost analysis procedure to apply to a routine analysis of (129)I in low and intermediate level radioactive wastes (LILWs), cement and paraffin solidified evaporated bottom and spent resin, which are produced from nuclear power plants (NPPs), pressurized water reactors (PWR), is presented. The (129)I is separated from other nuclides in LILWs using an anion exchange adsorption and solvent extraction by controlling the oxidation and reduction state and is then precipitated as silver iodide for counting the beta activity with a low background gas proportional counter (GPC). The counting efficiency of GPC was varied from 4% to 8% and it was reversely proportional to the weight of AgI by a self absorption of the beta activity. Compared to a higher pH, the chemical recovery of iodide as AgI was lowered at pH 4. It was found that the chemical recovery of iodide for the cement powder showed a lower trend by increasing the cement powder weight, but it was not affected for the paraffin sample. In this experiment, the overall chemical recovery yield of the cement and paraffin solidified LILW samples and the average weight of them were 67+/-3% and 5.43+/-0.53 g, 70+/-7% and 10.40+/-1.60 g, respectively. And the minimum detectable activity (MDA) of (129)I for the cement and paraffin solidified LILW samples was calculated as 0.070 and 0.036 Bq/g, respectively. Among the analyzed cement solidified LILW samples, (129)I activity concentration of four samples was slightly higher than the MDA and their ranges were 0.076-0.114 Bq/g. Also of the analyzed paraffin solidified LILW samples, five samples contained a little higher (129)I activity concentration than the MDA and their ranges were 0.036-0.107 Bq/g.

  3. The measurement of 129I for the cement and the paraffin solidified low and intermediate level wastes (LILWs), spent resin or evaporated bottom from the pressurized water reactor (PWR) nuclear power plants

    International Nuclear Information System (INIS)

    Park, S.D.; Kim, J.S.; Han, S.H.; Ha, Y.K.; Song, K.S.; Jee, K.Y.

    2009-01-01

    In this paper a relatively simple and low cost analysis procedure to apply to a routine analysis of 129 I in low and intermediate level radioactive wastes (LILWs), cement and paraffin solidified evaporated bottom and spent resin, which are produced from nuclear power plants (NPPs), pressurized water reactors (PWR), is presented. The 129 I is separated from other nuclides in LILWs using an anion exchange adsorption and solvent extraction by controlling the oxidation and reduction state and is then precipitated as silver iodide for counting the beta activity with a low background gas proportional counter (GPC). The counting efficiency of GPC was varied from 4% to 8% and it was reversely proportional to the weight of AgI by a self absorption of the beta activity. Compared to a higher pH, the chemical recovery of iodide as AgI was lowered at pH 4. It was found that the chemical recovery of iodide for the cement powder showed a lower trend by increasing the cement powder weight, but it was not affected for the paraffin sample. In this experiment, the overall chemical recovery yield of the cement and paraffin solidified LILW samples and the average weight of them were 67±3% and 5.43±0.53 g, 70±7% and 10.40±1.60 g, respectively. And the minimum detectable activity (MDA) of 129 I for the cement and paraffin solidified LILW samples was calculated as 0.070 and 0.036 Bq/g, respectively. Among the analyzed cement solidified LILW samples, 129 I activity concentration of four samples was slightly higher than the MDA and their ranges were 0.076-0.114 Bq/g. Also of the analyzed paraffin solidified LILW samples, five samples contained a little higher 129 I activity concentration than the MDA and their ranges were 0.036-0.107 Bq/g.

  4. Exploration of R2XM2 (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge): Structural Motifs, the novel Compound Gd2AlGe2 and Analysis of the U3Si2 and Zr>3Al2 Structure Types

    Energy Technology Data Exchange (ETDEWEB)

    McWhorter, Sean William [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    In the process of exploring and understanding the influence of crystal structure on the system of compounds with the composition Gd5(SixGe1-x)4 several new compounds were synthesized with different crystal structures, but similar structural features. In Gd5(SixGe1-x)4, the main feature of interest is the magnetocaloric effect (MCE), which allows the material to be useful in magnetic refrigeration applications. The MCE is based on the magnetic interactions of the Gd atoms in the crystal structure, which varies with x (the amount of Si in the compound). The crystal structure of Gd5(SixGe1-x)4 can be thought of as being formed from two 32434 nets of Gd atoms, with additional Gd atoms in the cubic voids and Si/Ge atoms in the trigonal prismatic voids. Attempts were made to substitute nonmagnetic atoms for magnetic Gd using In, Mg and Al. Gd2MgGe2 and Gd2InGe2 both possess the same 32434 nets of Gd atoms as Gd5(SixGe1-x)4, but these nets are connected differently, forming the Mo2FeB2 crystal structure. A search of the literature revealed that compounds with the composition R2XM2 (R=Sc, Y, Ti, Zr, Hf, rare earth; X=main group element; M=transition metal, Si, Ge) crystallize in one of four crystal structures: the Mo2FeB2, Zr>3Al2, Mn2AlB2 and W2CoB2 crystal structures. These crystal structures are described, and the relationships between them are highlighted. Gd2AlGe2 forms an entirely new crystal structure, and the details of its synthesis and characterization are given. Electronic structure calculations are performed to understand the nature of bonding in this compound and how

  5. Characterization of solidified radioactive waste and container due to the incorporation of high density polyethylene granules and powder in mortar matrices

    International Nuclear Information System (INIS)

    Peric, A.D.

    1999-01-01

    Powder and granules of the high density polyethylene (PEHD) were used to prepare mortar based matrices for immobilization of radioactive waste materials containing 137 Cs, as well as containers for solidified radioactive waste form. Seven types of matrices, differ due to the percentage of granules and filler material added, were investigated. PEHD powder and granules were added to mortar matrix preparations with the objective of improving physico-chemical characteristics of the radwaste-mortar matrix mixtures, in particular the leach-rate of the immobilized radionuclide, as well as mechanical characteristics either of mortar matrix and container. In this paper, only mechanical strength aspect of the investigated mortar and concrete container formulations, is presented. The equivalent diameter of the PEHD granules used was 2.0 mm. PEHD granules were used to replace 100 volume percent of stone granules, sifted size of 2.0 mm, normally used in the matrix preparation, in order to decrease the porosity and density of the mortar matrix and to avoid segregation of the stone particles at the bottom of the immobilized radioactive waste cylindrical form. PEHD powder, particle size of 250 micrometer, was added as filler to the mortar formulation, replacing 5, 8 and 10 wt% of the total cement weight in matrix formulation and 15 and 18 wt% of the total cement weight in container formulation. Cured samples were investigated on mechanical strength, using 150 MPa hydraulic press, in order to determine influence of added polyethylene granules and powder on samples resistance to mechanical forces that solidified waste materials and concrete containers may experience at the disposal site. Results of performed investigations have shown that samples prepared with polyethylene granules, replacing 100 wt% of the stone granules, have almost twice as much mechanical strength than samples prepared with stone aggregate. Samples prepared with PEHD granules and powder have mechanical strength

  6. Primary Dendrite Arm Spacing and Trunk Diameter in Al-7-Weight-Percentage Si Alloy Directionally Solidified Aboard the International Space Station

    Science.gov (United States)

    Ghods, M.; Tewari, S. N.; Lauer, M.; Poirier, D. R.; Grugel, R. N.

    2016-01-01

    Under a NASA-ESA collaborative research project, three Al-7-weight-percentage Si samples (MICAST-6, MICAST-7 and MICAST 2-12) were directionally solidified aboard the International Space Station to determine the effect of mitigating convection on the primary dendrite array. The samples were approximately 25 centimeters in length with a diameter of 7.8 millimeter-diameter cylinders that were machined from [100] oriented terrestrially grown dendritic Al-7Si samples and inserted into alumina ampoules within the Sample Cartridge Assembly (SCA) inserts of the Low Gradient Furnace (LGF). The feed rods were partially remelted in space and directionally solidified to effect the [100] dendrite-orientation. MICAST-6 was grown at 5 microns per second for 3.75 centimeters and then at 50 microns per second for its remaining 11.2 centimeters of its length. MICAST-7 was grown at 20 microns per second for 8.5 centimeters and then at 10 microns per second for 9 centimeters of its remaining length. MICAST2-12 was grown at 40 microns per second for 11 centimeters. The thermal gradient at the liquidus temperature varied from 22 to 14 degrees Kelvin per centimeter during growth of MICAST-6, from 26 to 24 degrees Kelvin per centimeter for MICAST-7 and from 33 to 31 degrees Kelvin per centimeter for MICAST2-12. Microstructures on the transverse sections along the sample length were analyzed to determine nearest-neighbor spacing of the primary dendrite arms and trunk diameters of the primary dendrite-arrays. This was done along the lengths where steady-state growth prevailed and also during the transients associated with the speed-changes. The observed nearest-neighbor spacings during steady-state growth of the MICAST samples show a very good agreement with predictions from the Hunt-Lu primary spacing model for diffusion controlled growth. The observed primary dendrite trunk diameters during steady-state growth of these samples also agree with predictions from a coarsening-based model

  7. Microdrilled cartilage defects treated with thrombin-solidified chitosan/blood implant regenerate a more hyaline, stable, and structurally integrated osteochondral unit compared to drilled controls.

    Science.gov (United States)

    Marchand, Catherine; Chen, Gaoping; Tran-Khanh, Nicolas; Sun, Jun; Chen, Hongmei; Buschmann, Michael D; Hoemann, Caroline D

    2012-03-01

    This study analyzed the long-term cartilage and subchondral bone repair of microdrilled defects treated with chitosan glycerol-phosphate/blood implant, using thrombin (Factor IIa) to accelerate in situ solidification. We also evaluated the cartilage repair response to six smaller microdrill holes compared with two larger holes. Bilateral knee trochlear cartilage defects were created in n=8 skeletally mature rabbits, drilled with six proximal 0.5 mm and two distal 0.9 mm holes, then covered with in situ-solidified IIa-implants (treated) or with IIa-alone (control). After 6.5 months of repair, cartilage repair tissues were analyzed by histological scoring and histomorphometry for hyaline matrix characteristics and osseous integration. Subchondral repair bone was analyzed by 3D microcomputed tomography and compared to acute defects (n=6) and intact trochlea (n=8). Implant-treated cartilage repair tissues had higher structural integrity through the entire defect (p=0.02), twofold higher percent staining for glycosaminoglycan (p=0.0004), and ~24% more collagen type II staining over the smaller drill holes (p=0.008) compared with controls. Otherwise, hole diameter had no specific effect on cartilage repair. The subchondral bone plate was partially restored in treated and control defects but less dense than intact trochlea, with evidence of incomplete regeneration of the calcified cartilage layer. More residual drill holes (p=0.054) were detected in control versus treated defects, and control defects with more than 40% residual holes presented abnormally thicker trabeculae compared with treated defects. Low osteoclast numbers after 6.5 months repair suggested that bone was no longer remodeling. The subchondral bone plate surrounding the defects exhibited a significant thickening compared with age-matched intact trochlea. These data suggest that debridement and drilling can lead to long-term subchondral bone changes outside the cartilage defect. Compared with drilled

  8. High-temperature deformation behavior and mechanical properties of rapidly solidified Al-Li-Co and Al-Li-Zr alloys

    International Nuclear Information System (INIS)

    Sastry, S.M.L.; Oneal, J.E.

    1984-01-01

    The deformation behavior at 25-300 C of rapidly solidified Al-3Li-0.6Co and Al-3Li-0.3Zr alloys was studied by tensile property measurements and transmission electron microscopic examination of dislocation substructures. In binary Al-3Li and Al-3Li-Co alloys, the modulus normalized yield stress increases with an increase in temperature up to 150 C and then decreases. The yield stress at 25 C of Al-3Li-0.3Zr alloys is 180-200 MPa higher than that of Al-3Li alloys. However, the yield stress of the Zr-containing alloy decreases drastically with increasing temperatures above 75 C. The short-term yield stresses at 100-200 C of the Al-3Li-based alloys are higher than that of the conventional high-temperature Al alloys. The temperature dependences of the flow stresses of the alloys were analyzed in terms of the magnitudes and temperature dependences of the various strengthening contributions in the two alloys. The dislocation substructures at 25-300 C were correlated with mechanical properties. 19 references

  9. Comparative Study on the Grain Refinement of Al-Si Alloy Solidified under the Impact of Pulsed Electric Current and Travelling Magnetic Field

    Directory of Open Access Journals (Sweden)

    Yunhu Zhang

    2016-07-01

    Full Text Available It is high of commercial importance to generate the grain refinement in alloys during solidification by means of electromagnetic fields. Two typical patterns of electromagnetic fields, pulsed electric currents (ECP and traveling magnetic field (TMF, are frequently employed to produce the finer equiaxed grains in solidifying alloys. Various mechanisms were proposed to understand the grain refinement in alloys caused by ECP and TMF. In this paper, a comparative study is carried out in the same solidification regime to investigate the grain refinement of Al-7 wt. %Si alloy driven by ECP and TMF. Experimental results show that the application of ECP or TMF can cause the same grain refinement occurrence period, during which the refinement of primary Al continuously occurs. In addition, the related grain refinement mechanisms are reviewed and discussed, which shows the most likely one caused by ECP and TMF is the promoted dendrite fragmentation as the result of the ECP-induced or TMF-induced forced flow. It suggests that the same grain refinement process in alloys is provoked when ECP and TMF are applied in the same solidification regime, respectively.

  10. Growth and microstructure formation of isothermally-solidified Zircaloy-4 joints brazed by a Zr-Ti-Cu-Ni amorphous alloy ribbon

    Science.gov (United States)

    Kim, K. H.; Lim, C. H.; Lee, J. G.; Lee, M. K.; Rhee, C. K.

    2013-10-01

    The microstructure and growth characteristics of Zircaloy-4 joints brazed by a Zr48Ti16Cu17Ni19 (at.%) amorphous filler metal have been investigated with regard to the controlled isothermal solidification and intermetallic formation. Two typical joints were produced depending on the isothermal brazing temperature: (1) a dendritic growth structure including bulky segregation in the central zone (at 850 °C), and (2) a homogeneous dendritic structure throughout the joint without segregation (at 890 °C). The primary α-Zr phase was solidified isothermally, nucleating to grow into a joint with a cellular or dendritic structure. Also, the continuous Zr2Ni and particulate Zr2Cu phases were formed in the segregated center zone and at the intercellular region, respectively, owing to the different solubility and atomic mobility of the solute elements (Ti, Cu, and Ni) in the α-Zr matrix. A disappearance of the central Zr2Ni phase was also rate-controlled by the outward diffusion of the Cu and Ni elements. When the detrimental Zr2Ni intermetallic phase was eliminated by a complete isothermal solidification at 890 °C, the strengths of the joints were high enough to cause yielding and fracture in the base metal, exceeding those of the bulk Zircaloy-4, at room temperature as well as at elevated temperatures (up to 400 °C).

  11. Composition, Taste, Aroma, and Antioxidant Activity of Solidified Noncentrifugal Brown Sugars Prepared from Whole Stalk and Separated Pith of Sugarcane (Saccharum officinarum L.).

    Science.gov (United States)

    Takahashi, Makoto; Ishmael, Mutanda; Asikin, Yonathan; Hirose, Naoto; Mizu, Masami; Shikanai, Takesi; Tamaki, Hajime; Wada, Koji

    2016-10-25

    In this study, 2 types of solidified noncentrifugal brown sugars (W-NCS and P-NCS) were prepared from the whole stalk and separated pith, respectively, of raw sugarcane (Saccharum officinarum L.). These products were discriminated in terms of their quality attributes, including color, sugars and minerals composition, taste, aroma, and antioxidant activity. The brown color of P-NCS was clearly different compared with that of W-NCS with a color difference value (ΔE * ) of 9.36. There was no difference in the sugars and minerals composition between the 2 types of sugar, which led to very similar taste profiles. However, P-NCS had a weaker aroma intensity than W-NCS did. Moreover, P-NCS retained more than 60% of the antioxidant activity of W-NCS. The information gleaned from this study might be used to select appropriate end-uses for these 2 types of sugars. © 2016 Institute of Food Technologists®.

  12. Speciation and determination of ultra trace amounts of chromium by solidified floating organic drop microextraction (SFODME) and graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Moghadam, Masoud Rohani [Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195-741 (Iran, Islamic Republic of); Dadfarnia, Shayessteh, E-mail: sdadfarnia@yazduni.ac.ir [Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195-741 (Iran, Islamic Republic of); Haji Shabani, Ali Mohammad [Department of Chemistry, Faculty of Science, Yazd University, Yazd 89195-741 (Iran, Islamic Republic of)

    2011-02-15

    Solidified floating organic drop microextraction (SFODME) method in combination with graphite furnace atomic absorption spectrometry (GFAAS) has been used for the determination of chromium species in water and urine samples. 1-undecanol containing 2-thenoyltrifluoroacetone (TTA) was used as a selective chelating agent for the extraction of Cr(III). The total Cr was determined after the reduction of Cr(VI) to Cr(III) with hydroxylamine. The concentration of Cr(VI) was determined from the difference between the concentration of total chromium and the Cr(III). Several variables such as the sample pH, concentration of TTA, salt concentration, extraction time and the sample volume were investigated in detail. Under the optimum conditions, the limit of detection of the proposed method was 0.006 {mu}g l{sup -1} for Cr(III) and the relative standard deviation for six replicate determinations at 0.1 {mu}g l{sup -1} Cr(III) was 5.1%. The proposed method was successfully applied for the determination of chromium species in tap water, well water, mineral water, and urine samples.

  13. Standard test method for accelerated leach test for diffusive releases from solidified waste and a computer program to model diffusive, fractional leaching from cylindrical waste forms

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method provides procedures for measuring the leach rates of elements from a solidified matrix material, determining if the releases are controlled by mass diffusion, computing values of diffusion constants based on models, and verifying projected long-term diffusive releases. This test method is applicable to any material that does not degrade or deform during the test. 1.1.1 If mass diffusion is the dominant step in the leaching mechanism, then the results of this test can be used to calculate diffusion coefficients using mathematical diffusion models. A computer program developed for that purpose is available as a companion to this test method (Note 1). 1.1.2 It should be verified that leaching is controlled by diffusion by a means other than analysis of the leach test solution data. Analysis of concentration profiles of species of interest near the surface of the solid waste form after the test is recommended for this purpose. 1.1.3 Potential effects of partitioning on the test results can...

  14. Optimization of dispersive liquid-phase microextraction based on solidified floating organic drop combined with high-performance liquid chromatography for the analysis of glucocorticoid residues in food.

    Science.gov (United States)

    Huang, Yuan; Zheng, Zhiqun; Huang, Liying; Yao, Hong; Wu, Xiao Shan; Li, Shaoguang; Lin, Dandan

    2017-05-10

    A rapid, simple, cost-effective dispersive liquid-phase microextraction based on solidified floating organic drop (SFOD-LPME) was developed in this study. Along with high-performance liquid chromatography, we used the developed approach to determine and enrich trace amounts of four glucocorticoids, namely, prednisone, betamethasone, dexamethasone, and cortisone acetate, in animal-derived food. We also investigated and optimized several important parameters that influenced the extraction efficiency of SFOD-LPME. These parameters include the extractant species, volumes of extraction and dispersant solvents, sodium chloride addition, sample pH, extraction time and temperature, and stirring rate. Under optimum experimental conditions, the calibration graph exhibited linearity over the range of 1.2-200.0ng/ml for the four analytes, with a reasonable linearity(r 2 : 0.9990-0.9999). The enrichment factor was 142-276, and the detection limits was 0.39-0.46ng/ml (0.078-0.23μg/kg). This method was successfully applied to analyze actual food samples, and good spiked recoveries of over 81.5%-114.3% were obtained. Copyright © 2017. Published by Elsevier B.V.

  15. Microstructure investigation of NiAl-Cr(Mo) interface in a directionally solidified NiAl-Cr(Mo) eutectic alloyed with refractory metal

    International Nuclear Information System (INIS)

    Chen, Y.X.; Cui, C.Y.; Guo, J.T.; Li, D.X.

    2004-01-01

    The microstructure of a directionally solidified NiAl-Cr(Mo) eutectic alloyed with refractory metal in as-processed and heat-treated states has been studied by means of scanning electron microscopy and high resolution electron microscopy (HREM). The microstructure of the NiAl-Cr(Mo) eutectic was characterized by lamellar Cr(Mo) phases embedded within NiAl matrix with common growth direction of . The interface between NiAl and lamellar Cr(Mo) did not have any transition layers. Misfit dislocations were observed at the NiAl-Cr(Mo) interface. In addition to lamellar Cr(Mo) phases, coherent Cr(Mo, Ni, Al) precipitates and NiAl precipitates were also observed in the NiAl matrix and lamellar Cr(Mo) phases, respectively. After hot isostatic pressing and heat treatment, the NiAl-Cr(Mo) interfaces became smooth and straight. Square array of misfit dislocations was directly observed at the (0 0 1) interface between NiAl and Cr(Mo, Ni, Al) precipitate. The configuration of misfit dislocation network showed a generally good agreement with prediction based on the geometric O-lattice model

  16. Sustained-release diclofenac potassium-loaded solid lipid microparticle based on solidified reverse micellar solution: in vitro and in vivo evaluation.

    Science.gov (United States)

    Chime, Salome Amarachi; Attama, Anthony Amaechi; Builders, Philip F; Onunkwo, Godswill C

    2013-01-01

    To formulate sustained-release diclofenac potassium-loaded solid lipid microparticles (SLMs) based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties. SRMS consisting of mixtures of Phospholipon® 90H and Softisan® 154 were used to formulate diclofenac potassium-loaded SLMs. Characterization based on the particle size and morphology, stability and encapsulation efficiency (EE%) were carried out on the SLMs. In vitro release was carried out in simulated intestinal fluid (pH 7.5). Anti-inflammatory and ulcerogenic properties were studied using rats. Maximum EE% of 95%, 94% and 93% were obtained for SLMs formulated with SRMS 1:1, 2:1 and 1:2, respectively. In vitro release showed about 85-90% drug release at 13 h. Diclofenac potassium-loaded SLMs showed good anti-inflammatory and gastro-protective properties. Diclofenac potassium-loaded SLMs based on SRMS could be used orally or parenterally under controlled conditions, for once daily administration.

  17. Measurement of the leaching rate of radionuclide 134Cs from the solidified radioactive sources in Portland cement mixed with microsilica and barite matrixes

    International Nuclear Information System (INIS)

    Shaaban, Ismail; Assi, Nasim

    2011-01-01

    Portland cement was mixed with radionuclide 134 Cs to produce low-level radioactive sources. These sources were surrounded with cement mixed with different materials like microsilica and barite. The leaching rate of 134 Cs from the solidified radioactive source in Portland cement alone was found to be 4.481 x 10 -4 g/cm 2 per day. Mixing this Portland cement with microsilica and with barite reduced significantly the leaching rate to 1.091 x 10 -4 g/cm 2 per day and 3.153 x 10 -4 g/cm 2 per day for 1 wt.% mixing, and to 1.401 x 10 -5 g/cm 2 per day and 1.703 x 10 -4 g/cm 2 per day for 3 wt.% mixing, respectively. It was also found that the application of a latex paint reduced these leaching rates by about 6.5%, 20.3% and 13.3% for Portland cement, cement mixed with microsilica and with barite, respectively. The leaching data were also analyzed using the polynomial method. The obtained results showed that cement mixed with microsilica and with barite can be effectively used for radioactive sources solidification.

  18. Simultaneous extraction and quantification of lamotrigine, phenobarbital, and phenytoin in human plasma and urine samples using solidified floating organic drop microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Asadi, Mohammad; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Abbasi, Bijan

    2015-07-01

    A novel and simple method based on solidified floating organic drop microextraction followed by high-performance liquid chromatography with ultraviolet detection has been developed for simultaneous preconcentration and determination of phenobarbital, lamotrigine, and phenytoin in human plasma and urine samples. Factors affecting microextraction efficiency such as the type and volume of the extraction solvent, sample pH, extraction time, stirring rate, extraction temperature, ionic strength, and sample volume were optimized. Under the optimum conditions (i.e. extraction solvent, 1-undecanol (40 μL); sample pH, 8.0; temperature, 25°C; stirring rate, 500 rpm; sample volume, 7 mL; potassium chloride concentration, 5% and extraction time, 50 min), the limits of detection for phenobarbital, lamotrigine, and phenytoin were 1.0, 0.1, and 0.3 μg/L, respectively. Also, the calibration curves for phenobarbital, lamotrigine, and phenytoin were linear in the concentration range of 2.0-300.0, 0.3-200.0, and 1.0-200.0 μg/L, respectively. The relative standard deviations for six replicate extractions and determinations of phenobarbital, lamotrigine, and phenytoin at 50 μg/L level were less than 4.6%. The method was successfully applied to determine phenobarbital, lamotrigine, and phenytoin in plasma and urine samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry in water samples

    Directory of Open Access Journals (Sweden)

    Arpa Şahin Ç.

    2013-04-01

    Full Text Available A simple, rapid and inexpensive solidified floating organic drop microextraction (SFODME and flow injection flame atomic absorption spectrometric determination (FI-FAAS method for copper was developed. 3-amino-7-dimethylamino-2-methylphenazine (Neutral red, NR was used as the complexing agent. Several factors affecting the microextraction efficiency, such as, pH, NR and sodium dodecylbenzenesulfonate (SDBS concentration, extraction time, stirring rate, and temperature were investigated and optimized. Under optimized experimental conditions an enrichment factor of 541 was obtained for 100 mL of sample solution. The calibration graph was linear in the range of 0.5 – 20.0 ng mL–1 and the limit of detection (3s was 0.18 ng mL–1, the limit of quantification (10s was 0.58 ng mL–1. The relative standard deviation (RSD for 10 replicate measurements of 10 ng mL–1 copper was 2.7%. The developed method was successfully applied to the extraction and determination of copper in different certified reference materials (Estuarine water, Slew 3 and fortified water, TM 23.2 and real water samples and satisfactory results were obtained.

  20. Convection and macrosegregation in Al-19Cu alloy directionally solidified through an abrupt contraction in cross-section: A comparison with Al-7Si

    Science.gov (United States)

    Ghods, M.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2017-02-01

    Hypoeutectic Al-19 wt. % Cu alloys were directionally solidified in cylindrical molds that featured an abrupt cross-section decrease 9.5 to 3.2 mm in diameter). Thermo-solutal convection and cross-section-change-induced shrinkage flow effects on macrosegregation were investigated. Dendrite clustering and extensive radial macrosegregation was seen, particularly in the larger cross-section before contraction. This alloy shows positive longitudinal macrosegregation near the contraction followed by negative macrosegregation right after it; the extent of macrosegregation, however, decreases with increasing growth speed. The degree of thermo-solutal convection was compared to another study investigating directional solidification of Al-7 wt. % Si [1] in order to study the effect of solutal expansion coefficient on macrosegregation. An interesting change of the radial macrosegregation profile, attributable to the area-change-induced-shrinkage flow, was observed very close to the contraction. A two-dimensional model accounting for both shrinkage and thermo-solutal convection was used to simulate solidification, the resulting steepling as well as axial and radial macrosegregation. The experimentally observed macrosegregation associated with the contraction during directional solidification was well predicted by the numerical simulations.

  1. Macrosegregation Due to Convection in Al-19Cu Alloy Directionally Solidified Through an Abrupt Expansion in Cross-Section: A Comparison with Al-7Si

    Science.gov (United States)

    Ghods, M.; Lauer, M.; Grugel, R. N.; Tewari, S. N.; Poirier, D. R.

    2017-10-01

    Hypoeutectic Al-19 wt.% Cu alloys were directionally solidified at two different growth speeds in cylindrical molds that featured an abrupt increase in cross-section, from 3.2 to 9.5 mm in diameter. The effects of thermosolutal convection and shrinkage flow induced by the cross-section change on macrosegregation were investigated. Dendrite clustering and extensive radial macrosegregation were seen, particularly in the larger cross-section after expansion. Negative longitudinal macrosegregation right after the cross-section increase was observed; the extent of macrosegregation, however, decreases with increasing growth speed. Both thermal and flow effects due to cross-section change were seen to influence the radial macrosegregation immediately before, and after the expansion. Radial macrosegregation pattern was found to be changing as the mushy zone enters the larger cross-section region above the cross-section change where the solidification is in its unsteady state. The effect of the solutal expansion coefficient on macrosegregation was studied by comparing the degree of thermosolutal convection in Al-19 wt.% Cu with a previous study in which we investigated Al-7 wt.% Si. A two-dimensional model accounting for both shrinkage and thermosolutal convection was used to simulate the resulting steepling, as well as the axial and radial macrosegregation. The experimentally observed macrosegregation associated with the expansion during directional solidification is well predicted by the numerical simulations.

  2. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part I. Microstructural Characterization of Rapidly Solidified Solders

    Science.gov (United States)

    Reeve, Kathlene N.; Choquette, Stephanie M.; Anderson, Iver E.; Handwerker, Carol A.

    2016-12-01

    Particles of Cu x Al y in Sn-Cu-Al solders have previously been shown to nucleate the Cu6Sn5 phase during solidification. In this study, the number and size of Cu6Sn5 nucleation sites were controlled through the particle size refinement of Cu x Al y via rapid solidification processing and controlled cooling in a differential scanning calorimeter. Cooling rates spanning eight orders of magnitude were used to refine the average Cu x Al y and Cu6Sn5 particle sizes down to submicron ranges. The average particle sizes, particle size distributions, and morphologies in the microstructures were analyzed as a function of alloy composition and cooling rate. Deep etching of the samples revealed the three-dimensional microstructures and illuminated the epitaxial and morphological relationships between the Cu x Al y and Cu6Sn5 phases. Transitions in the Cu6Sn5 particle morphologies from faceted rods to nonfaceted, equiaxed particles were observed as a function of both cooling rate and composition. Initial solidification cooling rates within the range of 103 to 104 °C/s were found to be optimal for realizing particle size refinement and maintaining the Cu x Al y /Cu6Sn5 nucleant relationship. In addition, little evidence of the formation or decomposition of the ternary- β phase in the solidified alloys was noted. Solidification pathways omitting the formation of the ternary- β phase agreed well with observed room temperature microstructures.

  3. Length scale-dependent structural relaxation in Zr{sub 57.5}Ti{sub 7.5}Nb{sub 5}Cu{sub 12.5}Ni{sub 10}Al{sub 7.5} metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Scudino, S., E-mail: s.scudino@ifw-dresden.de [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Stoica, M. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Kaban, I. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany); Prashanth, K.G. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Vaughan, G.B.M. [European Synchrotron Radiation Facilities ESRF, BP 220, 38043 Grenoble (France); Eckert, J. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)

    2015-08-05

    Highlights: • Structural relaxation of metallic glasses studied by high-energy X-ray diffraction. • Free volume is not uniformly distributed across the atoms. • Annihilation of free volume (i.e. shrinking) during heating is observed in the MRO. • Increase of free volume (i.e. expansion) during heating occurs in the SRO. • First diffraction maximum in reciprocal space describes structural changes in MRO. - Abstract: Structural relaxation in ball-milled Zr{sub 57.5}Ti{sub 7.5}Nb{sub 5}Cu{sub 12.5}Ni{sub 10}Al{sub 7.5} glassy powders has been investigated by in-situ high-energy X-ray diffraction. The studies in reciprocal and real space reveal a contrasting behavior between medium- (MRO) and short-range order (SRO). The free volume is not uniformly distributed across the atoms: annihilation of free volume (i.e. shrinking) during heating is observed in the MRO, whereas an increase of free volume (i.e. expansion) occurs in the SRO, implying a denser SRO in the as-milled powder compared to the structurally relaxed material. This behavior is in agreement with the concepts of free volume and anti-free volume and can be attributed to the change of the coordination number in the first nearest-neighbor shell. Finally, the results demonstrate that the first diffuse diffraction maximum in reciprocal space is a reliable indicator to evaluate the structural changes occurring in the MRO.

  4. Single and double-layer composite microwave absorbers with hexaferrite BaZn{sub 0.6}Zr{sub 0.3}X{sub 0.3}Fe{sub 10.8}O{sub 19} (X = Ti, Ce, Sn) powders

    Energy Technology Data Exchange (ETDEWEB)

    Afghahi, Seyyed Salman Seyyed [Department of Materials Science and Engineering, Imam Hossein University, Tehran (Iran, Islamic Republic of); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Atassi, Yomen [Department of Applied Physics, Higher Institute for Applied Sciences and Technology, Damascus (Syrian Arab Republic); Stergiou, Charalampos A. [Lab. of Inorganic Materials, Centre for Research and Technology Hellas, 57001, Thermi (Greece)

    2017-01-15

    In the present study, substituted barium hexaferrites with the composition BaZn{sub 0.6}Zr{sub 0.3} × {sub 0.3}Fe{sub 10.8}O{sub 19} (where X = Ti, Ce, Sn) are prepared with the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and network analysis techniques are used to analyze the crystal phases, morphology, static magnetic and microwave absorption properties, respectively. Based on the recorded results, barium hexaferrite is the major phase obtained after milling of the powders for 20 h, followed by calcination at 1000 °C for 5 h. The morphology of the particles of the substituted ferrite samples is plate-like with hexagonal shape. The microwave absorption in the X-band of epoxy composites loaded with the ferrite fillers, either separately, in pairs or all together, has been extensively investigated. Multicomponent composites filled with the new hexaferrites under study are promising candidates for electromagnetic absorbers in the 8–12 GHz range. It is found that single-layer absorbers of 5 mm thickness with 45 wt% of a binary (Sn and Ti-doped hexaferrite) or ternary filler mixture exhibit the maximum bandwidth of 2.7 GHz at the level of −10 dB or maximum losses of 26.4 dB at 10.8 GHz, respectively. - Highlights: • Preparation of substituted hexaferrites via mechanical activation. • We designed a broad band microwave absorber with mixing powders. • We designed single layer absorber with RL{sub min} = −26.4 dB and 1.6 GHz bandwidth. • We designed double layer absorbers, as monoband absorbers at a matching frequency.

  5. Novel thermal barrier coatings based on La{sub 2}(Zr{sub 0.7}Ce{sub 0.3}){sub 2}O{sub 7}/8YSZ double-ceramic-layer systems deposited by electron beam physical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xu Zhenhua, E-mail: zhxuciac@yahoo.com.cn [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); He Shimei; He Limin; Mu Rende; Huang Guanghong [Beijing Institute of Aeronautical Materials, Department 5, P.O. Box 81-5, Beijing 100095 (China); Cao Xueqiang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2011-03-17

    Research highlights: > LZ7C3 and YSZ have good chemical compatibility for the formation of DCL coating. > DCL coating has a longer lifetime than that of single layer coating of LZ7C3 or YSZ. > Similar TECs of LZ7C3 with YSZ coatings and YSZ coating with TGO layer. > Unique growth modes of columns within DCL coating. > Outward diffusion of Cr element (bond coat) into LZ7C3 layer. - Abstract: Double-ceramic-layer (DCL) thermal barrier coatings (TBCs) of La{sub 2}(Zr{sub 0.7}Ce{sub 0.3}){sub 2}O{sub 7} (LZ7C3) and yttria stabilized zirconia (YSZ) were deposited by electron beam-physical vapor deposition (EB-PVD). The thermal cycling test at 1373 K in an air furnace indicates the DCL coating has a much longer lifetime than the single layer LZ7C3 coating, and even longer than that of the single layer YSZ coating. The superior sintering-resistance of LZ7C3 coating, the similar thermal expansion behaviors of YSZ interlayer with LZ7C3 coating and thermally grown oxide (TGO) layer, and the unique growth modes of columns within DCL coating are all very helpful to the prolongation of thermal cycling life of DCL coating. The failure of DCL coating is mainly a result of the reduction-oxidation of cerium oxide, the crack initiation, propagation and extension, the abnormal oxidation of bond coat, the degradation of t'-phase in YSZ coating and the outward diffusion of Cr alloying element into LZ7C3 coating.

  6. Stable, easily sintered BaCe{sub 0.5}Zr{sub 0.3}Y{sub 0.16}Zn{sub 0.04}O{sub 3-{delta}} electrolyte-based proton-conducting solid oxide fuel cells by gel-casting and suspension spray

    Energy Technology Data Exchange (ETDEWEB)

    Lin Bin; Dong Yingchao; Wang Songlin; Fang Daru; Ding Hanping; Zhang Xiaozhen; Liu Xingqin [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Meng Guangyao [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: bin@mail.ustc.edu.cn

    2009-06-10

    Protonic ceramic membrane fuel cells (PCMFCs) based on oxide proton conductors exhibit more advantages than traditional solid oxide fuel cells (SOFCs) based on oxygen-ion conducting electrolytes, such as low activation energy and high energy efficiency. In order to develop a simple and cost-effective route to fabricate PCMFCs with SrCo{sub 0.9}Sb{sub 0.1}O{sub 3-{delta}} (SCS) cubic perovskite cathode, a dense BaCe{sub 0.5}Zr{sub 0.3}Y{sub 0.16}Zn{sub 0.04}O{sub 3-{delta}} (BCZYZn) electrolyte was fabricated in situ metal oxide on a porous anode support by gel-casting and suspension spray, which is cost-effective, easy to realize, and suitable for mass-production. The key part of this process is to directly spray well-mixed suspension of BaCO{sub 3}, CeO{sub 2}, ZrO{sub 2}, Y{sub 2}O{sub 3} and ZnO instead of pre-synthesized BCZYZn ceramic powder on the anode substrate. With SCS cubic perovskite cathode synthesized by gel-casting on the bi-layer, single cells were assembled and tested with H{sub 2} as fuel and the static air as oxidant. An open-circuit potential of 0.987 V, a maximum power density of 364 mW cm{sup -2}, and a low polarization resistance of the electrodes of 0.07 {omega} cm{sup 2} was achieved at 700 deg. C.

  7. Study of xCo{sub 0.8}Ni{sub 0.2}Fe{sub 2}O{sub 4}+(1−x) Pb{sub 0.99625} La{sub 0.0025}Zr{sub 0.55}Ti{sub 0.45}O{sub 3} magnetoelectric composites

    Energy Technology Data Exchange (ETDEWEB)

    Dipti [Electroceramics Research Lab, G.V.M. Girls College, Sonepat 131001 (India); School of Physics & Materials Science, Thapar University, Patiala 147004 (India); Singh, Sangeeta, E-mail: Sangeetaasingh@gmail.com [Department of Physics, G.V.M. Girls College, Sonepat 131001 (India); Juneja, J.K. [Department of Physics, Hindu College, Sonepat 131001 (India); Raina, K.K. [School of Physics & Materials Science, Thapar University, Patiala 147004 (India); Dehradun Institute of Technology, DIT University, Dehradun 248009 (India); Kotnala, R.K. [National Physical Laboratory, Dr. K.S. Krishnan Marg, New Delhi 110012 (India); Prakash, Chandra [Solid State Physics Laboratory, Lucknow Road, Delhi 110054 (India)

    2016-06-01

    We are reporting here, the studies of the structural, dielectric, ferroelectric and magnetic properties of magnetoelectric composites of La modified lead zirconate titanate (PLZT) and Ni modified cobalt ferrite (CNFO) with compositional formula xCo{sub 0.8}Ni{sub 0.2}Fe{sub 2}O{sub 4}+(1−x) Pb{sub 0.99625}La{sub 0.0025}Zr{sub 0.55}Ti{sub 0.45}O{sub 3} (x=0.00, 0.05, 0.10, 0.15 and 1.00 by weight) prepared by the solid state reaction method. Coexistence of both the phases in composites was confirmed by X-Ray diffraction technique. The microstructure and average grain size were determined from Scanning Electron Micrograph (SEM) in backscattered mode. Both the phases could be observed clearly. The variations of dielectric properties with frequency and temperature were also studied. P–E and M–H hysteresis measurements were carried. Magnetoelectric coupling (ME) coefficient for samples with x=0.05 and 0.10 were measured as a function of DC magnetic field. Maximum value of ME coefficient (1.2 mV/cm Oe) and piezoelectric coefficient (96 pC/N) for x=0.05 were observed. - Highlights: • ME composites PLZT–CNFO were studied for various properties. • Substitution of Ni and La in CFO and in PZT phase improves ME Coefficient. • The samples are good for various application due to high ME coeff. of PLZT-CNFO.

  8. Effect of Sb{sub 2}O{sub 3} on the electrical properties of Ba{sub 0.9}Ca{sub 0.1}Zr{sub 0.1}Ti{sub 0.9}O{sub 3} ceramics fabricated using nanocrystals seed

    Energy Technology Data Exchange (ETDEWEB)

    Parjansri, P. [Rajamangala University of Technology Krungthep, Physics Division, Faculty of Science and Technology, Bangkok (Thailand); Intatha, U. [Mae Fah Luang University, School of Science, Chiang Rai (Thailand); Guo, R.; Bhalla, A.S. [University of Texas at San Antonio, Department of Electrical and Computer Engineering, Faculty of Engineering, San Antonio, TX (United States); Eitssayeam, S. [Chiang Mai University, Department of Physics and Materials Science, Faculty of Science, Chiang Mai (Thailand); Chiang Mai University, Materials Science Research Center, Faculty of Science, Chiang Mai (Thailand)

    2016-09-15

    This work was to investigate the effects of antimony oxide (Sb{sub 2}O{sub 3}) on the electrical properties of Ba{sub 0.9}Ca{sub 0.1}Zr{sub 0.1}Ti{sub 0.9}O{sub 3} (BCZT) ceramics and was prepared by adding 1 mol% of BCZT nanocrystals. The seed is nanocrystals of BCZT which was synthesized by the molten salt method. The ceramics powders were prepared by the mixed oxide method using BaCO{sub 3}, CaCO{sub 3}, ZrO{sub 2}, TiO{sub 2} as starting materials, and the BCZT seed was added as nanocrystal for induce phase transition. They were doped with x mol% Sb{sub 2}O{sub 3} (x = 0.0-0.5). Results indicated that all samples show pure perovskite phase. The Sb{sub 2}O{sub 3} enhanced the electrical properties of the ceramic systems. Excellent values of a dielectric constant (ε {sub r}) at room temperature (T{sub r}) were 4086 with sample of x = 0.5, and at Curie temperature (T{sub c}) was 15,485 for samples with x = 0.1. The highest remnant polarization (P{sub r}), piezoelectric charge coefficient (d{sub 33}), piezoelectric voltage coefficient (g{sub 33}), electromechanical coefficient for planar mode (k{sub p}) and thickness mode (k{sub t}) values were 6.3 μC/cm{sup 2}, 346 pC/N, 15.6 x 10{sup -3} Vm/N, 42 and 41 %, respectively, which were obtained for the sample of x = 0.2 mol% Sb. (orig.)

  9. A comparative EBSP study of microstructure and microtexture formation from undercooled Ni{sub 99}B{sub 1} melts solidified on an electrostatic levitator and an electromagnetic levitator

    Energy Technology Data Exchange (ETDEWEB)

    Li Mingjun [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Tsukuba Space Center, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan)]. E-mail: li.mingjun@aist.go.jp; Ishikawa, Takehiko [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Tsukuba Space Center, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan); Nagashio, Kosuke [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara Campus, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Kuribayashi, Kazuhiko [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Sagamihara Campus, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Yoda, Shinichi [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Tsukuba Space Center, ISS Science Project Office, 2-1-1 Sengen, Tsukuba, Ibaraki 305-8505 (Japan)

    2006-08-15

    Ni{sub 99}B{sub 1} alloys were solidified by containerless processing at various melt undercoolings on an electrostatic levitator (ESL) and an electromagnetic levitator (EML). A scanning electron microscope in combination with an electron backscatter diffraction pattern mapping technique was employed to reveal microstructures and microtextures formed on these two facilities. The microstructure consists of well-developed primary dendrites with coarse secondary arms in the alloys solidified on the ESL at low and medium undercooling levels, whereas equiaxed grains are yielded in alloys solidified on the EML at almost the same undercoolings. Further analysis indicates that the melt flow induced by the electromagnetic field in the EML may play a significant role in promoting fragmentation of primary dendrites in the mushy zone and thus resulting in equiaxed grains. In contrast, the primary dendrites in the alloy processed on the ESL can fully develop in the absence of melt flow. The fluid flow in the sample on the EML can rotate, move, and displace surviving fragments, yielding a random distribution of grain orientation and thus leading to a random microtexture at low and medium undercoolings. At high undercoolings, refined equiaxed grains can be obtained on both the ESL and the EML and the influence of melt flow on refinement seems negligible due to the enhanced driving force in capillarity and solute effects. A great number of coherent annealing twins are formed, making the pole figures more complex and random.

  10. Influence of Mn incorporation for Ni on the magnetocaloric properties of rapidly solidified off-stoichiometric NiMnGa ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Sushmita; Singh, Satnam; Roy, R.K.; Ghosh, M.; Mitra, A.; Panda, A.K., E-mail: akpanda@nmlindia.org

    2016-01-01

    The present investigation addresses the magnetocaloric behaviour in a series of Ni{sub 77−x}Mn{sub x}Ga{sub 23} (x=23, 24, 25, 27 and 29) rapidly solidified alloys prepared in the form of ribbons by melt spinning technique. The approach of the study is to identify the off-stoichiometric composition wherein room temperature magneto-structural transformation is achieved. The alloy chemistry was tailored through Mn incorporation for Ni such that the magnetic and structural transitions were at close proximity to achieve highest entropy value of ΔS equal to 8.51 J Kg{sup −1} K{sup −1} for #Mn{sub 24} ribbon measured at an applied field of 3 T. When such transitions are more staggered as in #Mn{sub 29} the entropy value of ribbon reduced to as low as 1.61 J Kg{sup −1} K{sup −1}. Near room temperature transformations in #Mn{sub 24} ribbon have been observed through calorimetric and thermomagnetic evaluation. Reverse martensitic transformation (martensite→autstenite) temperature indicates not only distinct change in the saturation flux density but also an inter-martensitic phase. Microstructural analysis of #Mn{sub 24} alloy ribbon revealed structural ordering with the existence of plate morphology evidenced for martensitic phase. - Highlights: • Magnetocaloric effect in a series of melt spun NiMnGa ribbon is addressed. • The alloy series revealed austenitic state as well as its presence with martensite. • The morphology of the ribbons has been shown and discussed through phase analysis. • Influence of magnetising field on entropy and relative cooling power is discussed. • Influence of intermartensitic state on magnetization plots have also been shown.

  11. Microstructural characterization of a rapidly solidified ultrahigh strength Al94.5Cr3Co1.5Ce1 alloy

    International Nuclear Information System (INIS)

    Ping, D.H.; Hono, K.; Inoue, A.

    2000-01-01

    The microstructure of a rapidly solidified Al 94.5 Cr 3 Co 1.5 Ce 1 alloy has been examined in detail by means of high resolution transmission electron microscopy (HRTEM) and atom probe field ion microscopy (APFIM). In the as-quenched microstructure, nanoscale particles of a solute-enriched amorphous phase and an Al-Cr compound are dispersed in randomly oriented fine grains of α-Al ( 200nm ). The interface between the Al grains and the amorphous particles is not smooth but irregular with atomic protrusions and concavities, suggesting that interfacial instability occurs during the solidification process. Nanoscale amorphous particles are formed as a result of solute trapping within the rapidly grown Al grains. After annealing at 400 C for 15 minutes grain growth occurs, and the interface of the Al grains is smoothed. The amorphous region trapped within the grains if crystallized to an Al-Cr compound, but no icosahedral phase has been confirmed. The APFIM results have revealed that Cr and Ce atoms have a similar partitioning behavior, i.e., they are rejected from the α-Al phase and partitioned into the trapped amorphous regions. On the other hand, Co atoms are not partitioned between the two phases in the as-quenched state but are partitioned into the α-Al grains in the annealed alloys being rejected from the Al compounds and finally form Al-Co compounds. Based on these microstructural characterization results, the origins of high strength of this alloy are discussed

  12. Air-assisted liquid–liquid microextraction by solidifying the floating organic droplets for the rapid determination of seven fungicide residues in juice samples

    Energy Technology Data Exchange (ETDEWEB)

    You, Xiangwei [Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101 (China); College of Science, China Agricultural University, Beijing 100193 (China); Xing, Zhuokan [College of Science, China Agricultural University, Beijing 100193 (China); Liu, Fengmao, E-mail: liufengmao@cau.edu.cn [College of Science, China Agricultural University, Beijing 100193 (China); Zhang, Xu [College of Science, China Agricultural University, Beijing 100193 (China)

    2015-05-22

    Highlights: • A novel AALLME-SFO method was firstly reported for pesticide residue analysis. • Solvent with low density and proper melting point was used as extraction solvent. • The formation of “cloudy solvent” with a syringe only. • The new method avoided the use of organic dispersive solvent. - Abstract: A novel air assisted liquid–liquid microextraction using the solidification of a floating organic droplet method (AALLME-SFO) was developed for the rapid and simple determination of seven fungicide residues in juice samples, using the gas chromatography with electron capture detector (GC-ECD). This method combines the advantages of AALLME and dispersive liquid–liquid microextraction based on the solidification of floating organic droplets (DLLME-SFO) for the first time. In this method, a low-density solvent with a melting point near room temperature was used as the extraction solvent, and the emulsion was rapidly formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent for ten times repeatedly using a 10-mL glass syringe. After centrifugation, the extractant droplet could be easily collected from the top of the aqueous samples by solidifying it at a temperature lower than the melting point. Under the optimized conditions, good linearities with the correlation coefficients (γ) higher than 0.9959 were obtained and the limits of detection (LOD) varied between 0.02 and 0.25 μg L{sup −1}. The proposed method was applied to determine the target fungicides in juice samples and acceptable recoveries ranged from 72.6% to 114.0% with the relative standard deviations (RSDs) of 2.3–13.0% were achieved. Compared with the conventional DLLME method, the newly proposed method will neither require a highly toxic chlorinated solvent for extraction nor an organic dispersive solvent in the application process; hence, it is more environmentally friendly.

  13. Air-assisted liquid–liquid microextraction by solidifying the floating organic droplets for the rapid determination of seven fungicide residues in juice samples

    International Nuclear Information System (INIS)

    You, Xiangwei; Xing, Zhuokan; Liu, Fengmao; Zhang, Xu

    2015-01-01

    Highlights: • A novel AALLME-SFO method was firstly reported for pesticide residue analysis. • Solvent with low density and proper melting point was used as extraction solvent. • The formation of “cloudy solvent” with a syringe only. • The new method avoided the use of organic dispersive solvent. - Abstract: A novel air assisted liquid–liquid microextraction using the solidification of a floating organic droplet method (AALLME-SFO) was developed for the rapid and simple determination of seven fungicide residues in juice samples, using the gas chromatography with electron capture detector (GC-ECD). This method combines the advantages of AALLME and dispersive liquid–liquid microextraction based on the solidification of floating organic droplets (DLLME-SFO) for the first time. In this method, a low-density solvent with a melting point near room temperature was used as the extraction solvent, and the emulsion was rapidly formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent for ten times repeatedly using a 10-mL glass syringe. After centrifugation, the extractant droplet could be easily collected from the top of the aqueous samples by solidifying it at a temperature lower than the melting point. Under the optimized conditions, good linearities with the correlation coefficients (γ) higher than 0.9959 were obtained and the limits of detection (LOD) varied between 0.02 and 0.25 μg L −1 . The proposed method was applied to determine the target fungicides in juice samples and acceptable recoveries ranged from 72.6% to 114.0% with the relative standard deviations (RSDs) of 2.3–13.0% were achieved. Compared with the conventional DLLME method, the newly proposed method will neither require a highly toxic chlorinated solvent for extraction nor an organic dispersive solvent in the application process; hence, it is more environmentally friendly

  14. Effect of rare-earth elements and quenching wheel speed on the structure, mechanical and thermal properties of rapidly solidified AZ91 Mg melt-spun ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Ekrami, A. [Iran University of Industries & Mines, Faculty of Engineering & High-Technology (Iran, Islamic Republic of); Shahri, F., E-mail: fshahri@irost.ir [Iranian Research Organization for Science & Technology, Department of Advanced Materials & Renewable Energy (Iran, Islamic Republic of); Mirak, A. [Iran University of Industries & Mines, Faculty of Engineering & High-Technology (Iran, Islamic Republic of)

    2017-01-27

    In this work, an attempt is made to study the effects of rare-earth elements as an additive (2 wt% of Ce base misch-metal) and various quenching wheel speeds (10–40 m/s) on the microstructure, thermal and mechanical properties of rapidly solidified AZ91 alloy prepared by single roller melt-spinning process. In this respect, all of the samples were studied using various techniques such as x-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC) and mechanical properties such as microhardness and tensile tests. The finding bore witness to proposed hypothesis in this study illustrating due to high affinity between Al and RE by adding 2 wt% rare-earth elements in the AZ91alloy, thermally stable Al{sub x}RE{sub y} intermetallic compounds are precipitated and the formation of β-Mg{sub 17}Al{sub 12} phases is reduced. DSC results revealed that by adding RE to AZ91 alloy, AlRE phases got stable up to 500 °C, while for the AZ91 sample, β-Mg{sub 17}Al{sub 12} phase was formed at temperature about 180 °C and then with increasing of temperature dissolved at 410 °C in the α-Mg matrix. Further it has been observed that the higher was the quenching wheel speed, the smaller was the grain size which in turn gives rise to a higher tensile properties (from 406 MPa for quenching wheel speed of 10 m/s to 510 MPa for 40 m/s) for the MM-added alloys. Tensile strength of 386 MPa was obtained for the AZ91 pure alloy which is prepared at wheel speed of 40 m/sec.

  15. Rapid Solidification of Sn-Cu-Al Alloys for High-Reliability, Lead-Free Solder: Part II. Intermetallic Coarsening Behavior of Rapidly Solidified Solders After Multiple Reflows

    Science.gov (United States)

    Reeve, Kathlene N.; Choquette, Stephanie M.; Anderson, Iver E.; Handwerker, Carol A.

    2016-12-01

    Controlling the size, dispersion, and stability of intermetallic compounds in lead-free solder alloys is vital to creating reliable solder joints regardless of how many times the solder joints are melted and resolidified (reflowed) during circuit board assembly. In this article, the coarsening behavior of Cu x Al y and Cu6Sn5 in two Sn-Cu-Al alloys, a Sn-2.59Cu-0.43Al at. pct alloy produced via drip atomization and a Sn-5.39Cu-1.69Al at. pct alloy produced via melt spinning at a 5-m/s wheel speed, was characterized after multiple (1-5) reflow cycles via differential scanning calorimetry between the temperatures of 293 K and 523 K (20 °C and 250 °C). Little-to-no coarsening of the Cu x Al y particles was observed for either composition; however, clustering of Cu x Al y particles was observed. For Cu6Sn5 particle growth, a bimodal size distribution was observed for the drip atomized alloy, with large, faceted growth of Cu6Sn5 observed, while in the melt spun alloy, Cu6Sn5 particles displayed no significant increase in the average particle size, with irregularly shaped, nonfaceted Cu6Sn5 particles observed after reflow, which is consistent with shapes observed in the as-solidified alloys. The link between original alloy composition, reflow undercooling, and subsequent intermetallic coarsening behavior was discussed by using calculated solidification paths. The reflowed microstructures suggested that the heteroepitaxial relationship previously observed between the Cu x Al y and the Cu6Sn5 was maintained for both alloys.

  16. Annealing-induced changes in chemical bonding and surface characteristics of chemical solution deposited Pb{sub 0.95}La{sub 0.05}Zr{sub 0.54}Ti{sub 0.46}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Batra, Vaishali [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States); Ramana, C.V. [Department of Mechanical Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Kotru, Sushma, E-mail: skotru@eng.ua.edu [Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, AL 35487 (United States)

    2016-08-30

    Highlights: • Influence of post-deposition annealing temperature (T{sub a} = 550 and 750 °C) on the chemical valence state and crystalline quality of PLZT thin films was investigated. • XPS analyses demonstrated the shift in binding energies of the constituent atoms which indicated change in chemical state with the change in T{sub a}. • Raman spectra revealed shift in optical modes with the change in T{sub a} indicating the change in phase and crystallinity in the films. • Higher T{sub a} (750 °C) resulted in PLZT films with perovskite structure, nanocrystalline morphology, and better chemical homogeneity. - Abstract: We report the effect of post deposition annealing temperature (T{sub a} = 550 and 750 °C) on the surface morphology, chemical bonding and structural development of lanthanum doped lead zirconate titanate (Pb{sub 0.95}La{sub 0.05}Zr{sub 0.54}Ti{sub 0.46}O{sub 3}; referred to PLZT) thin films prepared using chemical solution deposition method. Atomic force microscopy demonstrates formation of nanocrystallites in the film annealed at T{sub a} = 750 °C. X-ray photoelectron spectroscopy (XPS) analyses indicate that the binding energies (BE) of the Pb 4f, Zr 3d, and Ti 2p doublet experience a positive energy shift at T{sub a} = 750 °C, whereas the BE of O 1s and La 3d doublet show a negative shift with respect to the BE of the films annealed at T{sub a} = 750 °C. Thermal induced crystallization and chemical modification is evident from XPS results. The Ar+ sputtering of the films reveals change in oxidation state and chemical bonding between the constituent atoms, with respect to T{sub a}. Raman spectroscopy used to study phonon-light interactions show shift in longitudinal and transverse optical modes with the change in T{sub a}, confirming the change in phase and crystallinity of these films. The results suggest annealing at T{sub a} = 750 °C yield crystalline perovskite PLZT films, which is essential to obtain photovoltaic response from

  17. An investigation on phase transition behaviors in MgO-doped Pb{sub 0.99}(Zr{sub 0.95}Ti{sub 0.05}){sub 0.98}Nb{sub 0.02}O{sub 3} ferroelectric ceramics by Raman and dielectric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junxia, E-mail: wjunxia2002@163.com [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Wang, Genshui; Chen, Xuefeng [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Hu, Zhigao [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Nie, Hengchang; Cao, Fei [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Dong, Xianlin, E-mail: xldong@mail.sic.ac.cn [Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2015-03-15

    Highlights: • The phase transition behaviors were strongly dependent on MgO concentration. • The F{sub R(LT)}–F{sub R(HT)} phase transition temperature obviously shifted toward a lower temperature with increasing MgO addition. • The F{sub R(HT)}–cubic paraelectric (P{sub C}) phase transition changed to a higher temperature with increasing MgO addition. • The distortion of BO{sub 6} oxygen octahedron caused by B-site replacement of Mg{sup 2+} ions is proposed to explain the observed behaviors. • Superior room-temperature pyroelectric properties were obtained in 0.1 wt% MgO-modified PZTN 95/5 ceramics during F{sub R(LT)}–F{sub R(HT)} phase transition. - Abstract: The phase transition behaviors of Pb{sub 0.99}(Zr{sub 0.95}Ti{sub 0.05}){sub 0.98}Nb{sub 0.02}O{sub 3} ferroelectric ceramics doped with different MgO concentrations (0–0.2 wt%) were systematically investigated by Raman and dielectric measurements. Raman results showed that the phase transitions were strongly dependent on MgO concentration. It was found that the low temperature rhombohedral (F{sub R(LT)})–high temperature rhombohedral (F{sub R(HT)}) ferroelectric phase transition shifted toward a lower temperature with increasing MgO concentration up to 0.1 wt%, while the F{sub R(HT)}–cubic paraelectric (P{sub C}) phase transition changed to a higher temperature. The Raman results were in good agreement with phase transition determined by dielectric measurements. Moreover, it was indicated that the changes of Raman active modes were related to distortion of BO{sub 6} octahedra during the phase transitions. Then, the distortion of BO{sub 6} octahedron caused by B-site replacement of Mg{sup 2+} ions was proposed to explain the observed behaviors. In addition, the effects of MgO doping on the dielectric, ferroelectric and pyroelectric properties were also discussed.

  18. Solidified package-storage device

    International Nuclear Information System (INIS)

    Takakura, Masahide

    1998-01-01

    Vitrification products such as high level radioactive liquid wastes are contained in a solidification package. A containing tube for vertically containing the solidification packages in multi-stages is disposed such that it passes through a ceiling slab. A shielding plug for preventing leakage of radiation from the solidification packages is fitted to an upper opening thereof. A lid of the containing tube is fitted above the plug. The lid is a carbon steel plate having a thickness of 10cm or more. A heat insulation layer comprising glass wool or rock wool is formed on the lower surface of the ceiling slab. A radiation shielding layer comprising such as an iron plate is formed on the lower surface of the heat insulation layer. Then, deterioration of the ceiling slug by heat can be prevented by the heat insulation layer even if high temperature cooling air flown from the upper opening of a ventilation tube should reach the lower surface of the ceiling slab. (I.N.)

  19. Method of solidifying radioactive wastes

    International Nuclear Information System (INIS)

    Tomita, Toshihide; Minami, Yuji; Matsuura, Hiroyuki; Kageyama, Hisashi; Kobori, Junzo.

    1984-01-01

    Purpose: To perform the curing sufficiently even when copper hydroxide that interferes the curing reaction is contained in radioactive wastes. Method: Solidification of radioactive wastes containing copper hydroxide using thermoset resins is carried out under the presence of an alkaline material. The thermoset resin used herein is an polyester resin comprising unsaturated polyester and a polymerizable monomer. The alkaline substance usable herein can include powder or an aqueous solution of hydroxides or oxides of sodium, magnesium, calcium or the like. (Yoshino, Y.)

  20. Method of solidifying radioactive wastes

    International Nuclear Information System (INIS)

    Tomita, Toshihide; Minami, Yuji; Matsuura, Hiroyuki

    1984-01-01

    Purpose: To enable complete curing even when radioactive wastes contain those materials hindering the curing reaction, for example, copper hydroxide. Method: After admixing an alkaline substance to radioactive concentrated liquid wastes containing copper hydroxide or other amphoteric substances, they are dried, powderized and then cured with thermosetting resins. The thermosetting resins usable herein include, for example, those prepared by mixing an unsaturated polyester with a monomer such as styrene. When a polymerization initiator such as methyl ethyl ketone peroxide and a polymerization promotor are added to the mixture, it takes places curing reaction at normal temperature. Suitable alkaline substances usable herein are those which are insoluble to the liquid wastes and do not change the chemical form under heating and drying. (Yoshihara, H.)

  1. Wrinkling of solidifying polymeric coatings

    Science.gov (United States)

    Basu, Soumendra Kumar

    2005-07-01

    In coatings, wrinkles are viewed as defects or as desired features for low gloss, and texture. In either case, discovering the origin of wrinkles and the conditions that lead to their formation is important. This research examines what wrinkling requires and proposes a mechanism to explain the observations. All curing wrinkling coatings contain multi-functional reactants. Upon curing, all develop a depth-wise gradient in solidification that result in a cross-linked elastic skin atop a viscous bottom layer. It is hypothesized that compressive stress develops in the skin when liquid below diffuses up into the skin. High enough compressive stress buckles the skin to produce wrinkles. The hypothesis is substantiated by experimental and theoretical evidences. Effects of various application and compositional parameters on wrinkle size in a liquid-applied acrylic coating and a powder-applied epoxy coating were examined. All three components, namely resin, cross-linker and catalyst blocked with at least equimolar volatile blocker, proved to be required for wrinkling. The wrinkling phenomenon was modeled with a theory that accounts for gradient generation, cross-linking reaction and skinning; predictions compared well with observations. Two-layer non-curing coatings that have a stiff elastic layer atop a complaint elastic bottom layer wrinkled when the top layer is compressed. The top layer was compressed by either moisture absorption or differential thermal expansion. Experimental observations compared well with predictions from a theory based on force balance in multilayer systems subjected to differential contraction or expansion. A model based on the Flory-Rehner free energy of a constrained cross-linked gel was constructed that predicts the compressive stress generated in a coating when it absorbs solvent. Linear stability analysis predicts that when a compressed elastic layer is attached atop a viscous layer, it is always unstable to buckles whose wavelength exceeds a critical value; more cross-linking and poor solvent produce higher wavelength, lower amplitude wrinkles. When a compressed elastic layer is attached atop an elastic layer and subjected to more than a critical compressive stress, it is unstable to intermediate wavelengths of buckling; better solvent, higher ratio of bottom-to-top layer thickness, and lower bottom layer modulus produce higher wavelength, higher amplitude wrinkles.

  2. Effect of permeable flow on cyclic layering in solidifying magma bodies: Insights from an analog experiment of diffusion-precipitation systems

    Science.gov (United States)

    Toramaru, A.; Yamauchi, S.

    2012-04-01

    Characteristic structures such as rhythmic layering, cress cumulate, cross bedding, perpendicular feldspar rock etc, are commonly observed in layered intrusion or shallow magmatic intrusions. These structures result from complex processes including thermal and compositional diffusions, crystallization, crystal settling, convection and interaction among three phases (crystals, bubble, melt). In order to understand how the differentiation proceeds in solidifying magma bodies from each characteristic structure together with chemical signatures, it is necessary to evaluate the relative importance among these elemental processes on structures. As an attempt to evaluate the effect of advection on a diffusion-related structure, we carried out an analog experiment of Liesegang system using lead-iodide (PbI2) crystallization in agar media which have been normally used to prohibit convection. In the ordinary Liesegang band formation experiments including only diffusion and crystallization kinetics without any advection and convection, the precipitation bands develop with regular spacing following a geometric progression due to two-component diffusion and reaction with supersaturation. This type of banding structure has been advocated as the same type of cyclic layering or vesicle layering (a sort of rhythmic layering) in dykes or sills. In order to see the effect of one-directional advection on Liesegang band, we apply the electric field (5 V to 25 V for a distance 15 cm) along the concentration gradient in agar media, thereby counteracting flows of lead anion Pb2+ and iodide ion I- are driven at constant velocities. The flows of anions and ions are equivalent to the permeable flows in porous media of crystal mush. The resultant precipitation structures exhibit very curious banding structure in which band spacings do not change with distance, are nearly constant and quite narrow, depending on the voltage, unlike those in ordinary Liesegang bands in which band spacings

  3. The research of Ti-rich zone on the interface between TiCx and aluminum melt and the formation of Ti3Al in rapid solidified Al-Ti-C master alloys

    International Nuclear Information System (INIS)

    Jiang Kun; Ma Xiaoguang; Liu Xiangfa

    2009-01-01

    In the present work, the thermodynamic tendency of formation of Ti-rich zone on the interface between TiC x and aluminum melt is calculated and a high titanium concentration can exist in the zone according to the thermodynamic calculation. Rapid solidified Al-5Ti-0.5C master alloy is analyzed by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). The appearance of Ti 3 Al in the master alloy results from the existence of high-concentration Ti-rich zone.

  4. The effects of low-molecular-weight emulsifiers in O/W-emulsions on microviscosity of non-solidified oil in fat globules and the mobility of emulsifiers at the globule surfaces

    DEFF Research Database (Denmark)

    Munk, Merete B.; Erichsen, Henriette Rifbjerg; Andersen, Mogens Larsen

    2014-01-01

    caseinate and different combinations of lactic acid ester of monoglyceride (LACTEM), unsaturated monoglycerides (GMU) or saturated monoglyceride (GMS) were studied. The non-solidified oil in emulsions made with LACTEM. +. GMU had a high microviscosity, whereas the emulsion made with GMS had a low...... of the spin probe on the droplet surfaces. Conversely, in presence of LACTEM and GMS, the protein surface loads decreased and high surface mobilities were observed. Based on these results it is argued that the high macroscopic viscosity and lipid agglomeration of emulsions containing GMU is due to a lipid...

  5. Synthesis of ceramic BaCe{sub 0.7}Zr{sub 0,1}Y{sub 0.2}O{sub 3-δ} electrolyte containing ZnO through the method hidrogel; Sintese do eletrolito ceramico BaCe{sub 0,7}Z{sub 0,1}Y{sub 0,2}O{sub 3-}δ com adicao de ZnO atraves do metodo hidrogel

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, J.H.A.; Fagury Neto, E.; Rabelo, A.A., E-mail: adriano@unifesspa.edu.br [Universidade Federal do Sul e Sudeste do Para (FEMAT/UNIFESSPA), Maraba, PA (Brazil)

    2014-07-01

    The solid oxide fuel cells are promising sources of sustainable energy, once they produce electricity from an electrochemical reaction only with steam water as the product of this reaction. In this paper the synthesis of ceramic electrolyte BaCe{sub 0.7}Zr{sub 0.1}Y{sub 0.2}O{sub 3-δ} using the hydrogel method which involves using an organic gelatin inexpensive and nontoxic modifying the conventional route of polymeric precursor was performed. It was used different amounts of the sintering additive ZnO to decrease the sintering temperature, typically around 1600 °C, towards a minimum relative density of 95%. The polymeric resin was pyrolyzed at 300 °C, subjected to calcination at 600 °C and sintering at temperatures of 1350, 1400 and 1450 °C for 2 hours. Characterizations were carried out by determination of relative density and apparent porosity and using the techniques of differential thermal analysis and simultaneous thermogravimetric, X-ray diffraction and scanning electron microscopy.(author)

  6. Stable, easily sintered BaCe{sub 0.5}Zr{sub 0.3}Y{sub 0.16}Zn{sub 0.04}O{sub 3-{delta}} electrolyte-based protonic ceramic membrane fuel cells with Ba{sub 0.5}Sr{sub 0.5}Zn{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} perovskite cathode

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Bin; Hu, Mingjun; Ma, Jianjun; Meng, Guangyao [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), 96 Jinzhai Road, Hefei, Anhui 230026 (China); Jiang, Yinzhu [Department of Materials Science and Engineering, University of Science and Technology of China (USTC), 96 Jinzhai Road, Hefei, Anhui 230026 (China); Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Tao, Shanwen [Department of Chemistry, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom)

    2008-09-01

    A stable, easily sintered perovskite oxide BaCe{sub 0.5}Zr{sub 0.3}Y{sub 0.16}Zn{sub 0.04}O{sub 3-{delta}} (BCZYZn) as an electrolyte for protonic ceramic membrane fuel cells (PCMFCs) with Ba{sub 0.5}Sr{sub 0.5}Zn{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (BSZF) perovskite cathode was investigated. The BCZYZn perovskite electrolyte synthesized by a modified Pechini method exhibited higher sinterability and reached 97.4% relative density at 1200 C for 5 h in air, which is about 200 C lower than that without Zn dopant. By fabricating thin membrane BCZYZn electrolyte (about 30 {mu}m in thickness) on NiO-BCZYZn anode support, PCMFCs were assembled and tested by selecting stable BSZF perovskite cathode. An open-circuit potential of 1.00 V, a maximum power density of 236 mW cm{sup -2}, and a low polarization resistance of the electrodes of 0.17 {omega} cm{sup 2} were achieved at 700 C. This investigation indicated that proton conducting electrolyte BCZYZn with BSZF perovskite cathode is a promising material system for the next generation solid oxide fuel cells. (author)

  7. Potential assessment of using fly ash as a binding agent for stabilization and solidification of dredged material; Potentialbedoemning av flygaskor som bindemedelskomponent foer stabilisering och solidifiering (s/s) av muddermassor

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmsson, Anna; Holm, Goeran; Lagerlund, Johan; Maijala, Aino; Macsik, Josef

    2010-04-15

    Over the next few years, about 200 000-800 000 m3 of contaminated sediments, with a muddy, slimy texture, high water ratio and low strength, shall be dredged annually in the development of ports and maintenance dredging of navigable waterways. Dumping at sea is limited since the dredged materials are contaminated. Land disposal requires transports and land area and is thus high in costs. In the construction of new port areas, large volumes of crushed rock, etc. are normally used as construction filling materials. These materials can be replaced by stabilised and solidified dredged materials, with modified geotechnical properties. The method of stabilising/solidifying (s/s) contaminated dredged materials has been used internationally for a long period of time, and, in more recent years, also in the Nordic countries. In Sweden, for instance, the Port of Gaevle and the Port of Oxeloesund have received permissions to reuse s/s-treated contaminated dredged materials in the port structures. Reuse of the stabilised/solidified masses in a geotechnical structure is supported by the new Framework Directive (2008/98/EC) on waste where great emphasis is placed on recycling. Within the project, fly ashes were inventoried with respect to suitability and availability. Five fly ashes, both individual fly ashes and mixtures of different fly ashes, were investigated in the laboratory as a binder component in a binder mix consisting of 50% cement, 20% Merit 5000 and 30% fly ash. Sediment from the Port of Gaevle were stabilised with a binder mixture amount of 150 kg/m3. Produced samples were examined in terms of strength, permeability and leaching. An assessment of the fly ashes' potential was performed based on technological, environmental and economical aspects, as well as market demand and the acceptance of stabilised and solidified dredged materials as construction material. The results show that fly ash, together in a binder mixture with construction cement and slag cement

  8. Magnetic domain structure, crystal orientation, and magnetostriction of Tb{sub 0.27}Dy{sub 0.73}Fe{sub 1.95} solidified in various high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Pengfei [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Liu, Tie, E-mail: liutie@epm.neu.edu.cn [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Dong, Meng [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Yuan, Yi [School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China); Wang, Qiang [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China)

    2016-03-01

    In this paper, we studied how applying a high magnetic field during solidification of Tb{sub 0.27}Dy{sub 0.73}Fe{sub 1.95} alloys affected their magnetic domain structure, crystal orientation, and magnetostriction. We observed the morphology of the magnetic domain during solidification, finding it change with the applied field: from fiber like (0 T) to dot like and closure mixed (4.4 T) to fiber like (8.8 T) to fishbone like (11.5 T). The alloy solidified at 4.4 T showed the best contrast of light and dark in its domain image, widest magnetic domain, fastest magnetization, and highest magnetostriction; this alloy is followed in descending order by the alloys solidified at 11.5 T, 8.8 T, and 0 T. The orientation of the (Tb, Dy)Fe{sub 2} phase changed with magnetic field from random (0 T) to 〈111〉 (4.4 T) to 〈113〉 (8.8 T) to 〈110〉 (11.5 T). The improvement in magnetostriction was likely caused by modification of both the magnetization process and the alloy microstructure. - Highlights: • We present how magnetic field affects magnetic domain structure of Tb{sub 0.27}Dy{sub 0.73}Fe{sub 1.95}. • Morphology and width of magnetic domain change with increasing magnetic field. • Magnetization and magnetostriction of alloy change with increasing magnetic field. • A transformation of random–〈111〉–〈113〉–〈110〉 for (Tb, Dy)Fe{sub 2} orientation forms.

  9. Magnetoelectric effect of (1−x) Ba{sub 0.5}Sr{sub 0.5}Zr{sub 0.5}Ti{sub 0.5}O{sub 3}+(x) Ni{sub 0.12}Mg{sub 0.18}Cu{sub 0.2}Zn{sub 0.5}Fe{sub 2}O{sub 4} composites

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, Md. D., E-mail: dalilurrahaman1976@gmail.com [Department of Physics, University of Dhaka, Dhaka-1000 (Bangladesh); Saha, S.K.; Ahmed, T.N. [Department of Physics, University of Dhaka, Dhaka-1000 (Bangladesh); Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh); Saha, D.K. [Materials Science Division, Atomic Energy Centre, PO Box 164, Dhaka 1000 (Bangladesh); Hossain, A.K.M. Akther [Department of Physics, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh)

    2014-12-15

    The magnetoelectric composites with chemical compositions (1−x) Ba{sub 0.5}Sr{sub 0.5}Zr{sub 0.5}Ti{sub 0.5}O{sub 3}+(x) Ni{sub 0.12}Mg{sub 0.18}Cu{sub 0.2}Zn{sub 0.5}Fe{sub 2}O{sub 4} (x=20, 40, 60 and 80 wt%) was prepared by the conventional solid state reaction method. The presence of a biphase composition was confirmed by X-ray diffraction while the microstructure of the composites was studied by scanning electron microscopy revealing a good mixing of the two phases and a good densification of the bulk ceramics. The dielectric dispersion is observed at lower frequencies due to interfacial polarization arising from the interface of the two phases. At higher frequencies, the dielectric constant is almost constant due to the inability of electric dipoles to follow the first variation of the alternating applied electric field. The dielectric loss shows maxima which are attributed when the hopping frequency of electrons between different ionic sites becomes nearly equal to the frequency of the applied field. The linearity in the log(σ{sub AC}) vs. log(ω{sup 2}) plots confirmed the small polaron hopping type of conduction mechanism. The composite materials are found to exhibit an excellent frequency dependence of magnetic properties. In the high frequency range, with increasing ferrite concentration the initial permeability increases and cut-off frequency decreases. An optimal magnetoelectric coupling responding voltage of about 600 μV cm{sup −1} Oe{sup −1} is obtained for x=20 wt% at room temperature. - Highlights: • XRD patterns confirmed the coexistence of ferroelectric and ferrimagnetic phases. • Dielectric dispersion observed at low frequencies due to interfacial polarization. • Linearity in logσ{sub ac} vs. logω{sup 2} is due to small polaron hopping mechanism. • Maximum ME voltage coefficient 600 μV cm{sup −1} Oe{sup −1} observed for 20% of ferrite.

  10. Development of salt and pH-induced solidified floating organic droplets homogeneous liquid-liquid microextraction for extraction of ten pyrethroid insecticides in fresh fruits and fruit juices followed by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Torbati, Mohammadali; Farajzadeh, Mir Ali; Torbati, Mostafa; Nabil, Ali Akbar Alizadeh; Mohebbi, Ali; Afshar Mogaddam, Mohammad Reza

    2018-01-01

    A new microextraction method named salt and pH-induced homogeneous liquid-liquid microextraction has been developed in a home-made extraction device for the extraction and preconcentration of some pyrethroid insecticides from different fruit juice samples prior to gas chromatography-mass spectrometry. In the present work, an extraction device made from two parallel glass tubes with different lengths and diameters was used in the microextraction procedure. In this method, a homogeneous solution of a sample solution and an extraction solvent (pivalic acid) was broken by performing an acid-base reaction and the extraction solvent was produced in whole of the solution. The produced droplets of the extraction solvent went up through the solution and solidified using an ice-bath. They were collected without centrifugation step. Under the optimum conditions, limits of detection and quantification were obtained in the ranges of 0.006-0.038, and 0.023-0.134ngmL -1 , respectively. The enrichment factors and extraction recoveries of the selected analytes ranged from 365-460 to 73-92%, respectively. The relative standard deviations were lower than 9% for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 1ngmL -1 of each analyte. Finally, some fruit juice samples were effectively analyzed by the proposed method. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Implementation of an ex situ stabilization technique at the Sand Springs superfund site to solidify and stabilize acid tar sludges involving a quick-lime based stabilization process and innovative equipment design

    International Nuclear Information System (INIS)

    McManus, R.W.; Grajczak, P.; Wilcoxson, J.C.; Webster, S.D.

    1997-01-01

    An old refinery site was safely remediated a year before schedule and for 25% less than final engineering estimates for the stabilization remedy thanks to energetic project management and innovative design involving ex situ stabilization/solidification of acid tar sludges. A quicklime based process, Dispersion by Chemical Reaction (DCR trademark), was employed to solidify and stabilize (SS) over 103,000 cubic meters (135,000 cubic yards) of petroleum waste, mostly acidic tarry sludge. The SS process was selected over competing methods because it afforded minimal volume increase, could readily achieve Record of Decision (ROD) specified physical and chemical treatment goals, could be implemented with treatment equipment that minimized emissions, and could be performed with low reagent usage and at low cost. To ensure treatment goals were achieved and an accelerated schedule met, a custom designed and fabricated transportable treatment unit (TTU) was employed to implement the process. The treated material was visually soil-like in character, it was left in stockpiles for periods of time, and it was placed and compacted in the on site landfill using standard earth-moving equipment

  12. Simultaneous extraction and determination of albendazole and triclabendazole by a novel syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop combined with high performance liquid chromatography.

    Science.gov (United States)

    Asadi, Mohammad; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad

    2016-08-17

    A syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop was introduced and used for the simultaneous extraction of trace amounts of albendazole and triclabendazole from different matrices. The extracted analytes were determined by high performance liquid chromatography along with fluorescence detection. The analytical parameters affecting the microextraction efficiency including the nature and volume of the extraction solvent, sample volume, sample pH, ionic strength and the cycles of extraction were optimized. The calibration curves were linear in the range of 0.1-30.0 μg L(-1) and 0.2-30.0 μg L(-1) with determination coefficients of 0.9999 and 0.9998 for albendazole and triclabendazole respectively. The detection limits defined as three folds of the signal to noise ratio were found to be 0.02 μg L(-1) for albendazole and 0.06 μg L(-1) for triclabendazole. The inter-day and intra-day precision (RSD%) for both analytes at three concentration levels (0.5, 2.0 and 10.0 μg L(-1)) were in the range of 6.3-10.1% and 5.0-7.5% respectively. The developed method was successfully applied to determine albendazole and triclabendazole in water, cow milk, honey, and urine samples. Copyright © 2016. Published by Elsevier B.V.

  13. Impact of beryllium additions on thermal and mechanical properties of conventionally solidified and melt-spun Al–4.5 wt.%Mn–x wt.%Be (x = 0, 1, 3, 5) alloys

    International Nuclear Information System (INIS)

    Öz, Turan; Karaköse, Ercan; Keskin, Mustafa

    2013-01-01

    Highlights: • Thermal and mechanical properties of Al–Mn–Be alloys were investigated. • IQC Al–Mn–Be alloys were synthesized by the CS and MS techniques. • The volume fraction of IQC increases continuously with Be content. • The melting points of the QC i-phase were determined between 652 °C and 675 °C. • The maximum H V and σ values were found to be 124 kg/mm 2 and 458 MPa with the addition of 5% Be. - Abstract: The influence of beryllium (Be) addition on the quasicrystal-forming ability, thermal and mechanical properties of Al–4.5 wt.%Mn–x wt.%Be (x = 0, 1, 3, 5) alloys was investigated in this study. Quasicrystalline Al–Mn–Be alloys were synthesized by the conventionally casting and melt spinning techniques. The microstructures of the samples were characterized by scanning electron microscopy (SEM) and the phase composition was identified by X-ray diffractometry (XRD). The phase transition during the solidification process was studied by differential scanning calorimetry (DSC) and differential thermal analysis (DTA) under an Ar atmosphere. The mechanical properties of the conventionally solidified (CS) and melt-spun (MS) samples were measured by a Vickers micro-hardness indenter and tensile-strength tests. The Al–4.5 wt.%Mn alloy has a hexagonal structure and minor dendritic icosahedral quasicrystalline phase (IQC) precipitates surrounded by an α-Al matrix. Addition of Be into the Al–4.5 wt.%Mn alloy generates intermetallic Be 4 AlMn and IQC phases with the extinction of the hexagonal phase, and the fraction of IQC increases continuously with the increase in Be content. A considerable improvement in microhardness and tensile strength values was observed due to the addition of Be in different percentages into the composition

  14. Ligandless, ion pair-based and ultrasound assisted emulsification solidified floating organic drop microextraction for simultaneous preconcentration of ultra-trace amounts of gold and thallium and determination by GFAAS.

    Science.gov (United States)

    Fazelirad, Hamid; Taher, Mohammad Ali

    2013-01-15

    In the present work, a new, simple and efficient method for simultaneous preconcentration of ultra-trace amounts of gold and thallium is developed using an ion pair based-ultrasound assisted emulsification-solidified floating organic drop microextraction procedure before graphite furnace atomic absorption spectrometry determination. This methodology was used to preconcentrate the ion pairs formed between AuCl(4)(-) and TlCl(4)(-) and [C(23)H(42)]N(+) in a microliter-range volume of 1-undecanol. Several factors affecting the microextraction efficiency, such as HCl volume, type and volume of extraction solvent, sonication time, sample volume, temperature, ionic strength and [C(23)H(42)]NCl volume were investigated and optimized. Under the optimized conditions, the enrichment factor of 441 and 443 and calibration graphs of 2.2-89 and 22.2-667 ng L(-1) for gold and thallium were obtained, respectively. The intra- and inter-day precision of ± 4.4 and ± 4.9% for Au and ± 4.8 and ± 5.4% for Tl were obtained. The detection limit was 0.66 ng L(-1) for Au and 4.67 ng L(-1) for Tl. The results show that the liquid-liquid pretreatment using ion pair forming, is sensitive, rapid, simple and safe method for the simultaneous preconcentration of gold and thallium. The method was successfully applied for determination of gold and thallium in natural water and hair samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Solidifying incongruently melting intermetallic phases as bulk single phases using the example of Al{sub 2}Cu and Q-phase in the Al-Mg-Cu-Si system

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, Andrea [Institute of Materials Science and Technology, Friedrich-Schiller-University, Jena (Germany); Groebner, Joachim; Hampl, Milan [Institute of Metallurgy, Clausthal University of Technology, Clausthal-Zellerfeld (Germany); Engelhardt, Hannes [Institute of Materials Science and Technology, Friedrich-Schiller-University, Jena (Germany); Schmid-Fetzer, Rainer [Institute of Metallurgy, Clausthal University of Technology, Clausthal-Zellerfeld (Germany); Rettenmayr, Markus, E-mail: M.Rettenmayr@uni-jena.de [Institute of Materials Science and Technology, Friedrich-Schiller-University, Jena (Germany)

    2012-02-25

    Highlights: Black-Right-Pointing-Pointer Samples consisting of pure Al{sub 2}Cu and 95% Q-phase respectively were prepared. Black-Right-Pointing-Pointer The Q-phase composition is Al{sub 17}Cu{sub 9}Mg{sub 44}Si{sub 30}, its solubility range is negligible. Black-Right-Pointing-Pointer The Q-phase peritectic temperature was determined by DSC measurements as 703 Degree-Sign C. Black-Right-Pointing-Pointer A new thermodynamic dataset for the Q-phase has been assessed. - Abstract: Plane front directional solidification experiments were carried out for preparing incongruently melting intermetallic phases in the quaternary alloy system Al-Cu-Mg-Si, particularly the binary Al{sub 2}Cu phase and the quaternary phase ('Q-phase'). By this method, bulk samples that consist of only a single phase are generated. Sample sections consisting of 100% single phase Al{sub 2}Cu and of 95% Q-phase, respectively, were obtained. The composition of the Q-phase was measured by Energy Dispersive X-ray Spectroscopy (EDX). The measured concentrations are close to the Al{sub 3}Cu{sub 2}Mg{sub 9}Si{sub 7} composition that has recently been predicted as most stable by ab initio calculations. A peritectic temperature of 703 Degree-Sign C for the reaction Q {yields} L + Mg{sub 2}Si + (Si) was determined by differential scanning calorimetry (DSC). An optimization of the Calphad database was performed considering the measured composition and peritectic temperature. For validating the optimized database, Scheil calculations were performed and compared with the experimentally determined sequence of solidifying phases.

  16. Solidifying power station resins and sludges

    International Nuclear Information System (INIS)

    Willis, A.S.D.; Haigh, C.P.

    1984-01-01

    Radioactive ion exchange resins and sludges arise at nuclear power stations from various operations associated with effluent treatment and liquid waste management. As the result of an intensive development programme, the Central Electricity Generating Board (CEGB) has designed a process to convert power station resins and sludges into a shielded, packaged solid monolithic form suitable for final disposal. Research and development, the generic CEGB sludge/resin conditioning plant and the CEGB Active Waste Project are described. (U.K.)

  17. Structural perfection of directionally solidified lamellar eutectics

    International Nuclear Information System (INIS)

    Attallah, T.; Gurzleski, J.E.

    1976-01-01

    The mechanisms for the formation of faults in lamellar eutectics are reviewed, and it is postulated that faults play several roles in eutectic freezing with their exact importance depending on the specific alloy system and the growth conditions. Faults are not the cause of lamellar spiralling although they are necessary for it to occur. Lamellar spiralling is found to occur only when the crystallographic orientations of the two eutectic phases lead to a growth component normal to the lamellar plane, and although some systems such as Pb-Sn normally spiral it is possible for them to achieve orientation relationships where no spiralling occurs

  18. Method for solidifying liquid radioactive wastes

    International Nuclear Information System (INIS)

    Berreth, J.R.

    1976-01-01

    The quantity of nitrous oxides produced during the solidification of liquid radioactive wastes containing nitrates and nitrites can be substantially reduced by the addition to the wastes of a stoichiometric amount of urea which, upon heating, destroys the nitrates and nitrites, liberating nontoxic N 2 , CO 2 and NH 3 . 5 claims, no drawings

  19. Evolution of morphology in solidifying aluminium alloys

    NARCIS (Netherlands)

    Dijkstra, W.O.

    2007-01-01

    In the thesis two different models of solidification of aluminum alloys are presented and analyzed. The first 1--D solidification model is derived from the conservation of solute, heat and mass. With numerical experiments it is shown that simulations with the Finite Difference discretization must

  20. Method of solidifying radioactive ion exchange resin

    International Nuclear Information System (INIS)

    Minami, Yuji; Tomita, Toshihide

    1989-01-01

    Spent anion exchange resin formed in nuclear power plants, etc. generally catch only a portion of anions in view of the ion exchange resins capacity and most of the anions are sent while possessing activities to radioactive waste processing systems. Then, the anion exchange resins increase the specific gravity by the capture of the anions. Accordingly, anions are caused to be captured on the anion exchange resin wastes such that the specific gravity of the anion exchange resin wastes is greater than that of the thermosetting resins to be mixed. This enables satisfactory mixing with the thermosetting resins and, in addition, enables to form integral solidification products in which anion exchange resins and cation exchange resins are not locallized separately and which are homogenous and free from cracks. (T.M.)

  1. Thermodynamical Properties of the Solidified Rare Gases

    Energy Technology Data Exchange (ETDEWEB)

    Ebbsjoe, I

    1971-12-15

    Lattice parameter, isothermal bulk modulus and specific heat at constant volume are calculated from Helmholtz free energy for solid Ne, Ar, Kr and Xe. The lattice potential energy is expanded to the fourth order in the nuclear displacements. A perturbation treatment in the quasi harmonic approximation of the partition function includes the cubic anharmonic term to second order and the quartic to first order. Detailed numerical calculations are presented for two interatomic pair potentials, the Lennard-Jones (12,6) and the (exp,a,6). The three nearest neighbours have been taken into account. It is shown that earlier nearest neighbour calculations exaggerate the breakdown of the theory at higher temperatures

  2. Method of solidifying liquid radioactive wastes

    International Nuclear Information System (INIS)

    Pekar, A.; Petrovic, J.; Timulak, J.

    1987-01-01

    Liquid radioactive waste containing boric acid salts is mixed with zeolite tuff and neutralized by lime. Power plant fly ash containing single-component or mixed Portland cement is then added to the mixture. Prior to packaging, anion-active bitumen emulsion or an aqueous emulsion of fatty acid salts and of free fatty acids insoluble in water can be added. Examples are given listing accurate proportions of the individual components. The advantage of the said solidification method is the use of easily available raw materials and improved values of extractability of the resulting product radionuclides. (E.S.)

  3. Rapidly solidified long-range-ordered alloys

    International Nuclear Information System (INIS)

    Lee, E.H.; Koch, C.C.; Liu, C.T.

    1981-01-01

    The influence of rapid solidification processing on the microstructure of long-range-ordered alloys in the (Fe, Co, Ni) 3 V system has been studied by transmission electron microscopy. The main microstructural feature of the as-quenched alloys was a fine cell structure (approx. 300 nm diameter) decorated with carbide particles. This structure was maintained aftr annealing treatments which develop the ordered crystal structure. Other features of the microstructures both before and after annealing are presented and discussed. 6 figures

  4. Leaching properties of solidified TRU waste forms

    International Nuclear Information System (INIS)

    Colombo, P.; Neilson, R.M. Jr.

    1979-01-01

    Safety analysis of waste forms requires an estimate of the ability of these forms to retain activity in the disposal environment. This program of leaching tests will determine the leaching properties of TRU contaminated incinerator ash waste forms using hydraulic cement, urea--formaldehyde, bitumen, and vinyl ester--styrene as solidification agents. Three types of leaching tests will be conducted, including both static and flow rate. Five generic groundwaters will be used. Equipment and procedures are described. Experiments have been conducted to determine plate out of 239 Pu, counter efficiency, and stability of counting samples

  5. Alternative solidified forms for nuclear wastes

    International Nuclear Information System (INIS)

    McElroy, J.L.; Ross, W.A.

    1976-01-01

    Radioactive wastes will occur in various parts of the nuclear fuel cycle. These wastes have been classified in this paper as high-level waste, intermediate and low-level waste, cladding hulls, and residues. Solidification methods for each type of waste are discussed in a multiple barrier context of primary waste form, applicable coatings or films, matrix encapsulation, canister, engineered structures, and geological storage. The four major primary forms which have been most highly developed are glass for HLW, cement for ILW, organics for LLW, and metals for hulls

  6. Comparison of Directionally Solidified Samples Solidified Terrestrially and Aboard the International Space Station

    Science.gov (United States)

    Angart, S.; Lauer, M.; Tewari, S. N.; Grugel, R. N.; Poirier, D. R.

    2014-01-01

    This article reports research that has been carried out under the aegis of NASA as part of a collaboration between ESA and NASA for solidification experiments on the International Space Station (ISS). The focus has been on the effect of convection on the microstructural evolution and macrosegregation in hypoeutectic Al-Si alloys during directional solidification (DS). Terrestrial DS-experiments have been carried out at Cleveland State University (CSU) and under microgravity on the International Space Station (ISS). The thermal processing-history of the experiments is well defined for both the terrestrially processed samples and the ISS-processed samples. As of this writing, two dendritic metrics was measured: primary dendrite arm spacings and primary dendrite trunk diameters. We have observed that these dendrite-metrics of two samples grown in the microgravity environment show good agreements with models based on diffusion controlled growth and diffusion controlled ripening, respectively. The gravity-driven convection (i.e., thermosolutal convection) in terrestrially grown samples has the effect of decreasing the primary dendrite arm spacings and causes macrosegregation. Dendrite trunk diameters also show differences between the earth- and space-grown samples. In order to process DS-samples aboard the ISS, the dendritic seed crystals were partially remelted in a stationary thermal gradient before the DS was carried out. Microstructural changes and macrosegregation effects during this period are described and have modeled.

  7. FY 1999 report on the results of R and D projects by local consortiums for immediate effects. R and D regarding high quality/high performance of lithium tantalate single crystal's solidifying growth and SAW wafer; 1999 nendo sankabutsu tankessho no ikusei to wafer no kohinshitsu konoritsuka ni kansuru kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-01

    The R and D project has been implemented for establishing, e.g., methods for growing oxide single crystals (e.g., lithium tantalate, LiTaO{sub 3}) to have the large and/or long products, technologies for polishing/cleaing the wafer products, and technologies for evaluating device performance. For solidifying growth and production technologies for lithium tantalate single crystals, pulling-up of the single crystal, 154 mm in body length and 12.9 kg, is succeeded by reducing temperature gradient at the crystal solid-liquid interface, increasing oxygen concentration, and improving the seed-sustaining system. Bright prospects have been obtained for the automated crystal pulling-up system, and high-precision control of crystal weight. For technologies for polishing/cleaning the wafers, the investigated cleaning methods include ELID polishing, mechanochemical polishing, and supersonic cleaning which uses two frequency bands of multi-supersonic and megasonic waves. For development of the technologies for evaluation/examination of the highly functional devices, the non-contact type method has been developed, which can measure the absolute level of SAW speed at a high speed and precision. (NEDO)

  8. FY 1999 report on the results of R and D projects by local consortiums for immediate effects. R and D regarding high quality/high performance of lithium tantalate single crystal's solidifying growth and SAW wafer; 1999 nendo sankabutsu tankessho no ikusei to wafer no kohinshitsu konoritsuka ni kansuru kenkyu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-01

    The R and D project has been implemented for establishing, e.g., methods for growing oxide single crystals (e.g., lithium tantalate, LiTaO{sub 3}) to have the large and/or long products, technologies for polishing/cleaing the wafer products, and technologies for evaluating device performance. For solidifying growth and production technologies for lithium tantalate single crystals, pulling-up of the single crystal, 154 mm in body length and 12.9 kg, is succeeded by reducing temperature gradient at the crystal solid-liquid interface, increasing oxygen concentration, and improving the seed-sustaining system. Bright prospects have been obtained for the automated crystal pulling-up system, and high-precision control of crystal weight. For technologies for polishing/cleaning the wafers, the investigated cleaning methods include ELID polishing, mechanochemical polishing, and supersonic cleaning which uses two frequency bands of multi-supersonic and megasonic waves. For development of the technologies for evaluation/examination of the highly functional devices, the non-contact type method has been developed, which can measure the absolute level of SAW speed at a high speed and precision. (NEDO)

  9. Glass-forming ability and stability of ternary Ni-early transition metal (Ti/Zr/Hf) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Joysurya [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India); Ranganathan, S. [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India)]. E-mail: rangu@met.iisc.ernet.in

    2006-08-15

    Four Ni-bearing Ti, Zr and Hf ternary alloys of nominal composition Zr{sub 41.5}Ti{sub 41.5}Ni{sub 17}, Zr{sub 25}Ti{sub 25}Ni{sub 50}, Zr{sub 41.5}Hf{sub 41.5}Ni{sub 17} and Ti{sub 41.5}Hf{sub 41.5}Ni{sub 17} were rapidly solidified in order to produce ribbons. The Zr-Ti-Ni and Ti-Hf-Ni alloys become amorphous, whereas the Zr-Hf-Ni alloy shows precipitation of a cubic phase. The devitrification of all three alloys was followed and the relative tendency to form nanoquasicrystals and cF96 phases analysed. The relative glass-forming ability of the alloys can be explained by taking into account their atomic size difference. Addition of Ni often leads to quasicrystallisation or quasicrystal-related phases. This can be explained by the atomic radius and heat of mixing of the constituent elements. The phases precipitated at the initial stages of crystallisation indicate the possible presence of Frank-Kasper polyhedral structure in the amorphous alloys. Structural analysis reveals that the Laves and the anti-Laves phases have the same polyhedral structural unit, which is similar to the structural characteristics of glass.

  10. Acoustic emission from a solidifying aluminum-lithium alloy

    Science.gov (United States)

    Henkel, D. P.; Wood, J. D.

    1992-01-01

    Physical phenomena associated with the solidification of an AA2090 Al-Li alloy have been characterized by AE methods. Repeatable patterns of AE activity as a function of solidification time are recorded and explained for ultrahigh-purity (UHP) aluminum and an Al-4.7 wt pct Cu binary alloy, in addition to the AA2090 Al-Li alloy, by the complementary utilization of thermal, AE, and metallographic methods. One result shows that the solidification of UHP aluminum produces one discrete period of high AE activity as the last 10 percent of solid forms.

  11. Influence of quench rates on the properties of rapidly solidified ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. FeNbCuSiB based materials were produced in the form of ribbons by rapid solidification techniques. The crystallization, magnetic, mechanical and corrosion behaviour were studied for the prepared materials as a function of quenching rate from liquid to the solid state. Higher quench rates produced a more ...

  12. Testing and evaluation of solidified high-level waste forms

    International Nuclear Information System (INIS)

    De Batist Al, R.

    1983-01-01

    In addition to the preceding programme of the European Atomic Energy Community two new borosilicate glass compositions have been introduced. The chemical stability of these waste forms, in particular with respect to geological disposal conditions, is examined as well as effects of alpha-radiation and of devitrification. Leaching studies include theoretical and experimental investigations of the basic leaching mechanisms, the measurement of the leach rates of a number of critical radioisotopes and the influence on the leach rate of various parameters such as temperature, pressure pH and duration. Of particular interest is the simulation of repository conditions. Prelimimary results are described related to various mineral waters, granite and salt solutions. The surface layers generated on the waste forms during corrosion are investigated in detail using various experimental techniques such as scanning electron microscopy, X-ray analysis and alpha particle energy loss spectra measurements. The radiation stability was further tested by continuing investigations of the samples doped with 238 Pu in the course of the previous programme; density and leach rate variations were measured. Effects on the leach rate of devitrification resulting from various heat treatments of active glass samples were also investigated

  13. Characterization of consolidated rapidly solidified Cu-Nb ribbons

    International Nuclear Information System (INIS)

    Ebrahimi, F.; Henne, M.L.C.

    1997-01-01

    Copper-niobium ribbons produced by melt-spinning were compacted by swaging and consolidated using HIPping. Final processing to obtain in-situ composites was done by swaging. The strength of the composite is discussed in terms of the composition and morphology of the niobium phase as evaluated using electron microscopy techniques

  14. Ordering in rapidly solidified Ni/sub 2/Mo

    International Nuclear Information System (INIS)

    Kulkarni, U.D.; Dey, G.K.; Banerjee, S.

    1988-01-01

    Ordering processes in the Ni-Mo system have been a subject of several investigations. Although the ordering behaviour of the Ni/sub 4/Mo and the Ni/sub 3/Mo has been examined in detail, no such study has been reported in the case of the Ni/sub 2/Mo alloy. The lack of experimental work on ordering transformations in Ni/sub 2/Mo is presumably due to the difficulty in obtaining a single phase fcc alloy of this composition. Enhanced solid solubility of Mo in Ni, which accompanies rapid solidification processing (RSP) makes the formation of such a phase possible. The ordering processes in Ni-Mo based alloys show several remarkable features. Firstly, the alloy (15 - 28 at % Mo) quenched from the α -phase filed exhibit a short range order (SRO) characterized by the presence of intensity maxima at /1 1/2 0/ fcc positions of the reciprocal space. This state of SRO has been attributed to the occurrence of 1 1/2 O spinodal ordering in the system. Secondly, the transformation from the state of SRO to the equilibrium/metastable coherent long range ordered (LRO) structures appears to take place in a continuous manner at relatively low temperatures of aging. Three different coherent LRO structures, namely: the equilibrium Ni/sub 4/Mo (prototype structure D1/sub a/) and the metastable Ni/sub 3/Mo (DO/sub 22/) and Ni/sub 2/Mo (Pt/sub 2/Mo) structures have reported to evolve from the SRO alloy, depending upon the aging treatment and the composition of the alloy

  15. Procedure for conditioning high-level solidified wastes

    Energy Technology Data Exchange (ETDEWEB)

    Hild, W; Krause, H; Scheffler, K

    1974-05-30

    The molds of glass, ceramic or basalt-similar mass in which highly radioactive wastes are incorporated are used for the conditioning of waste waters and/or of sewage or precipitating sludge or of natural water to obtain drinking water, prior to the end storage. By means of the gamma-radiation they emit, the viruses and bacteria and worm eggs are killed off as well as the poisonous, and organic substances such as, e.g., chlorated aromatics are destroyed. Furthermore, the filtration power is increased by coagulation, and the sludge is drained. Natural water is degermed. In particular, fission product mixtures of light water reactors can be incorporated in the molds. The molds are immersed in the media.

  16. Particle Engulfment and Pushing by Solidifying Interfaces (PEPSI)

    Science.gov (United States)

    Stefanescu, Doru Michael; Curreri, Peter A.; Juretsko, F.; Pang, H.; Phalnikar, R.

    1993-01-01

    The preliminary definition phase included the following actions: producing a science requiring document (draft), producing a science requirements document (preliminary), updating the flight program proposal, project review at NASA Marshall Space Flight Center, and research work as defined in the statement of work. The first three items of this plan have been delivered by the University of Alabama to NASA according to schedule. A project review meeting was held at MSFC on June 29, 1993. Consequently, this part of the report will address the results of the research work performed in the Solidification Laboratory at the University of Alabama during the first six months of the project.

  17. Development of high temperature fasteners using directionally solidified eutectic alloys

    Science.gov (United States)

    George, F. D.

    1972-01-01

    The suitability of the eutectics for high temperature fasteners was investigated. Material properties were determined as a function of temperature, and included shear parallel and perpendicular to the growth direction and torsion parallel to it. Techniques for fabricating typical fastener shapes included grinding, creep forming, and direct casting. Both lamellar Ni3Al-Ni3Nb and fibrous (Co,Cr,Al)-(Cr,Co)7C3 alloys showed promise as candidate materials for high temperature fastener applications. A brief evaluation of the performance of the best fabricated fastener design was made.

  18. Performance assessment of stabilised/solidified waste-forms

    OpenAIRE

    Antemir, Aurora

    2010-01-01

    A method to treat contaminated land is stabilisation/solidification (S/S), which physically encapsulates and chemically stabilises the contaminants. The current knowledge on the behaviour of S/S systems is based upon scarce and incomplete data, mostly obtained from laboratory simulations or small scale trials of the technology. The field performance of S/S soils is largely unknown.\\ud \\ud The aim of this research was to improve the understanding of the long-term performance of S/S soils, by e...

  19. Liquid emulsion scintillators which solidify for facile disposal

    International Nuclear Information System (INIS)

    O'Brien, R.E.; Krieger, J.K.

    1981-01-01

    A liquid organic scintillation cocktail is described which counts solutions of radiolabelled compounds containing up to ten % by volume of water with high efficiency and is readily polymerizable to a solid for easy disposal. The cocktail comprises a polymerizable organic solvent, a solubilizing agent, an intermediate solvent, and an organic scintillator. A method of disposing of liquid organic scintillation cocktail waste and a kit useful for practising the method are also described. (U.K.)

  20. Rapidly solidified Ti-25Al-Nb alloys

    International Nuclear Information System (INIS)

    Ward, C.H.; Broderick, T.F.; Jackson, A.G.; Rowe, R.G.; Froes, F.H.

    1987-01-01

    Alloys based on the Ti-25Al-Nb intermetallic system were studied to determine the effects of rapid solidification on structure. Compositions ranging from 12 to 30 at% niobium which are beyond the α/sub 2/ single phase field were evaluated. Alloys were prepared using a melt spinning process. The resulting ribbons were characterized using transmission electron microscopy and x-ray diffraction. The alloys were all found to have a retained ordered B2 structure in the melt spun condition with an antiphase domain size that significantly decreased with increasing niobium content. ''Tweed-like'' striations, indicating planar shear strain, were observed in all compositions. The characteristic diffraction pattern of an ordered ''omega-type'' phase was found to occur in the patterns taken from the 12 at% niobium alloy

  1. Microstructure of amorphous and crystalline zirconium alloys rapiddly solidified

    International Nuclear Information System (INIS)

    Monteiro, W.A.; Bezerra, G.H

    1986-01-01

    In this work we report microstructural studies of rapidly solification of Zr-30% at Cu alloy. This composition was chosen because it is the Zr rich limit of glass formation range. The ribbons were prepared by melt spinning system (cooling rate is estimated in 10 6 K/s) and the average thickness of the microscopy were prepared by double jet electropolishing to investigate the microstructure of the ribbon. It was observed amorphos and crystalline regions. In the crystalline regions occured a radial growth morphology with stress contrats. The beginning of solidification is a polimorphous reaction and the shape of the micrograins is similar to spherulitic form. The average diameter of the grains are 0,5 μm or less. (Author) [pt

  2. Testing and evaluation of solidified high-level waste forms

    International Nuclear Information System (INIS)

    Engelmann, C.

    1984-01-01

    The report describes research by several laboratories on the behaviour, in aqueous and salt environments, of borosilicate glass ceramics proposed for the solidification of nuclear wastes by the European Community. Results were obtained on inactive simulates, doped materials, and on borosilicate glass containing real radioactive waste. The influence of many important parameters were studied: leaching mode, nature of the leachant, pH, pressure, temperature, duration of the treatment, etc. The results of tests lasting for as little as a few hours or for as long as several hundred days, at temperatures up to 200 0 C or under pressures up to 200 bars, are presented. Numerous analytical techniques (ESCA, EMP, IRR, SEM, etc.) were used to determine the structure and the chemical composition of the altered layer developed by hydration at the glass surface. Information is also given on physical properties of the borosilicate glass: crystallization phase separation, alpha-irradiation stability, mechanical and thermal stability, etc. Finally, preliminary results on the structure and composition of hollandite ceramics are given

  3. Embedding methods of solidified waste in metal matrices

    International Nuclear Information System (INIS)

    Neumann, W.

    1979-01-01

    The embedding of simulated waste calcines by three different methods (vacuum-pressure casting, centrifugal casting, and metal stirred with the calcines) was investigated. The experimental performance is described and advantages and disadvantages noted. The feasibility of embedding fines by stirring in metal was shown. In addition, an estimation of the influence of porosity on the properties of composites was carried out

  4. Process for solidifying high-level nuclear waste

    Science.gov (United States)

    Ross, Wayne A.

    1978-01-01

    The addition of a small amount of reducing agent to a mixture of a high-level radioactive waste calcine and glass frit before the mixture is melted will produce a more homogeneous glass which is leach-resistant and suitable for long-term storage of high-level radioactive waste products.

  5. Leaching of solidified TRU-contaminated incinerator ash

    International Nuclear Information System (INIS)

    Fuhrmann, M.; Colombo, P.

    1984-01-01

    Leach rate and cumulative fractional releases of plutonium were determined for a series of laboratory-scale waste forms containing transuranic (TRU) contaminated incinerator ash. The solidification agents from which these waste forms were produced are commercially available materials for radioactive waste disposal. The leachants simulate groundwaters with chemical compositions that are indiginous to different geological media proposed for repositories. In this study TRU-contaminated ash was incorporated into waste forms fabricated with portland type I cement, urea-formaldehyde, polyester-styrene or Pioneer 221 bitumen. The ash was generated at the dual-chamber incinerator at the Rocky Flats Plant. These waste forms contained between 1.25 x 10 -2 and 4.4 x 10 -2 Ci (depending on the solidification agent) of mixed TRU isotopes comprised primarily of 239 Pu and 240 Pu. Five leachant solutions were prepared consisting of: (1) demineralized water, (2) simulated brine, (3) simplified sodium-dominated groundwater (30 meq NaCl/liter), (4) simplified calcium-dominated groundwater (30 meq CaCl 2 /liter), and (5) simplified bicarbonate-dominated groundwater (30 meq NaHCO 3 /liter). Cumulative fractional releases were found to vary significantly with different leachants and solidification agents. In all cases waste forms leached in brine gave the lowest leach rates. Urea-formaldehyde had the greatest release of radionuclides while polyester-styrene and portland cement had approximately equivalent fractional releases. Cement cured for 210 days retained radionuclides three times more effectively than cement cured only 30 days

  6. Investigation on migration of Uranium in solidified materials

    International Nuclear Information System (INIS)

    Bai Yun; Zhu Xiaohong; Yang Guangwen; Liao Junsheng; Shuai Zhenqing

    2011-01-01

    The sorption and migration behaviors of uranium in soils and cement were studied by column test. The results show that the sorption ratio of soil is bigger than that of cement. Specific radioactivity of 235 U in the soil and cement samples is basically the same as that of environmental soil, and specific radioactivity of 235 U varies little with the sampling depth. The results should provide valuable information to nuclear facility decommissioning. (authors)

  7. Addiction Counseling Accreditation: CACREP's Role in Solidifying the Counseling Profession

    Science.gov (United States)

    Hagedorn, W. Bryce; Culbreth, Jack R.; Cashwell, Craig S.

    2012-01-01

    In this article, the authors discuss the Council for Accreditation of Counseling and Related Educational Programs' (CACREP) role in furthering the specialty of addiction counseling. After sharing a brief history and the role of counselor certification and licensure, the authors share the process whereby CACREP developed the first set of…

  8. Experimental evaluation of cement materials for solidifying sodium nitrate

    International Nuclear Information System (INIS)

    Sasaki, Tadashi; Numata, Mamoru; Suzuki, Yasuhiro; Kubo, Yoshikazu

    2003-03-01

    Low-level liquid waste containing sodium nitrate is planned to be transformed to salt block by evaporation with sodium borate in the Low-level Waste Treatment Facility (LWTF), then salt block will be stored temporally. It should be important to investigate the method how to treat these liquid waste suitable to final disposal criteria that will be settled in future. Cement solidification is one of promising candidates because it has been achieved as the solidification material for the shallow land disposal. The research was conducted to evaluate applicability of various cement materials to solidification of sodium nitrate. The following cements were tested. Ordinary Portland Cement (OPC). Portland Blast-furnace Slag Cement; C type (PBFSC). Alkali Activated Slag Cement (AASC, supplied by JGC). The test results are as follows; (1) AASC is characterized by a high sodium nitrate loading (-70 wt%) compared with other types of cement material. High fluidity of the cement paste, high strength after solidification, and minimization of free water on the cement paste are achieved under all test conditions. (2) OOPC and PBFSC produced free water on the cement paste in the early days and delayed the hardening period. 3 or more days are required to harden evan with 30 wt% content of sodium nitrate. (3) Though PBFSC contains blast furnace slag similar to AASC, there is no advantage prior to OPC. To design an ideal cement conditioning system for sodium nitrate liquid waste in the LWTF, the further studies are necessary such as the simulated waste test, Kd test, pilot test, and layout design. (author)

  9. Solidified reverse micellar solutions (SRMS): A novel approach for ...

    African Journals Online (AJOL)

    AMARA

    loppment to effectively overcome physical and biological barriers related to .... preparation. The lipids are ... thermo-analytic technique for studying lipids and their mixtures. It gives ... analysis gives further insights on the preferred orientation.

  10. Solidified reverse micellar solutions (SRMS): A novel approach for ...

    African Journals Online (AJOL)

    AMARA

    The types of SRMS-based drug delivery systems include solid lipid nanoparticles (SLN), solid lipid microparticles (SLM), tablets and suppositories amongst others. The work ..... based SLM for intramuscular administration of gentamicin.

  11. Assessment of the loss of radioactive isotopes from solidified wastes

    International Nuclear Information System (INIS)

    Godbee, H.W.; Kibbey, A.H.; Joy, D.S.

    1978-01-01

    Amounts of 137 Cs and 239 Pu entering the environment by leaching of grout products are predicted as functions of time, considering a 55-gal drum as a finite source and as a semi-infinite medium with and without decay. Significant differences between finite-cylinder and semi-infinite-medium calculations appear after a few years of leaching when the effective diffusivity (D) is 1.2 x 10 -9 cm 2 /s, but do not appear up to 3,000 years when D is 6.0 x 10 -16 cm 2 /s. The smaller D is and the larger the size is, the longer a finite specimen will behave as a semi-infinite medium

  12. Method of melting to solidify radioactive powder wastes

    International Nuclear Information System (INIS)

    Ootsuka, Katsuyuki; Miyazaki, Hitoshi.

    1981-01-01

    Purpose: To improve the microwave irradiation efficiency in a melting furnace. Constitution: Pelletization, sludgification and granularization are carried out as powderous dust reducing treatment. In the granularization, for example, radioactive burning ashes are sent from a hopper to a mixer and mixed with processing aids such as binders. Then, they are pelletized in a pelletizer into granular products and sent to a microwave melting furnace by way of a sieve screen. The granular products are melted by microwaves from a microwave guide tube and taken out through an exit. This can prevent powderous dusts from floating and scattering in the melting furnace and prevent the reduction in the microwave irradiation efficiency due to generation of electric discharges. (Seki, T.)

  13. Safety analysis of sea transportation of solidified reactor wastes

    International Nuclear Information System (INIS)

    Devell, L.; Edlund, O.; Kjellbert, N.; Grundfelt, B.; Milchert, T.

    1980-06-01

    A central handling and storage facility (ALMA) for low- and medium-level reactor waste from Swedish nuclear power plants is being planned and the transportation to it will be by sea. A safety assessment devoted to the potential environmental impacts from the transportation is presented. (Auth.)

  14. Altering mucus rheology to "solidify" human mucus at the nanoscale.

    Directory of Open Access Journals (Sweden)

    Samuel K Lai

    Full Text Available The ability of mucus to function as a protective barrier at mucosal surfaces rests on its viscous and elastic properties, which are not well understood at length scales relevant to pathogens and ultrafine environmental particles. Here we report that fresh, undiluted human cervicovaginal mucus (CVM transitions from an impermeable elastic barrier to non-adhesive objects sized 1 microm and larger to a highly permeable viscoelastic liquid to non-adhesive objects smaller than 500 nm in diameter. Addition of a nonionic detergent, present in vaginal gels, lubricants and condoms, caused CVM to behave as an impermeable elastic barrier to 200 and 500 nm particles, suggesting that the dissociation of hydrophobically-bundled mucin fibers created a finer elastic mucin mesh. Surprisingly, the macroscopic viscoelasticity, which is critical to proper mucus function, was unchanged. These findings provide important insight into the nanoscale structural and barrier properties of mucus, and how the penetration of foreign particles across mucus might be inhibited.

  15. Solidify, An LLVM pass to compile LLVM IR into Solidity

    Energy Technology Data Exchange (ETDEWEB)

    2017-07-12

    The software currently compiles LLVM IR into Solidity (Ethereum’s dominant programming language) using LLVM’s pass library. Specifically, his compiler allows us to convert an arbitrary DSL into Solidity. We focus specifically on converting Domain Specific Languages into Solidity due to their ease of use, and provable properties. By creating a toolchain to compile lightweight domain-specific languages into Ethereum's dominant language, Solidity, we allow non-specialists to effectively develop safe and useful smart contracts. For example lawyers from a certain firm can have a proprietary DSL that codifies basic laws safely converted to Solidity to be securely executed on the blockchain. In another example, a simple provenance tracking language can be compiled and securely executed on the blockchain.

  16. Development of methods to extralt and solidify highly radioactive waste

    International Nuclear Information System (INIS)

    Arnek, R.; Persson, A.; Faelth, L.; Annehed, H.

    1977-06-01

    Zeolites are proposed as selective ion exchange materials to extract highly radioactive fission products as cesium 137 and strontium 90, and corrosion products. The zeolites 13X, F and PC showed a high adsorption capacity for cesium and strontium. A heat treatment at 800-1300 degrees C for about two hours gave a vitrified material. The chemical resistance of the heat treated zeolites was tested in a soxhlets-apparatus, were a streaming solution at 100 degrees C was in contact with the zeolite for 1-2 days. For all cases, the amount of dissolved strontium was below the detection threshold.(L.K.)

  17. Synthesis and characterization of metallic nuclear fuels; Sintese e caracterizacao de combustiveis nucleares metalicos

    Energy Technology Data Exchange (ETDEWEB)

    Longen, F.R., E-mail: frlongen@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Medianeira, PR (Brazil); Barco, R.; Paesano Junior, A. [Universidade Estadual de Maringa (UEM), PR (Brazil); Pagano Junior, L. [Centro Tecnologico da Marinha (CETEM), Sao Paulo, SP (Brazil)

    2014-07-01

    U-Zr-Mo and U-Zr-Gd ternary alloys, potentially useful as metallic nuclear fuel, were prepared at different concentrations by arc-melting and characterized by X-ray diffraction. Those alloys containing molybdenum were submitted to thermal annealing in inert atmosphere, followed by quenching in water. These samples were measured before and after the thermal treatment. The diffractometric results evidenced that the as-cast alloys solidified mostly with a body centered cubic structure (γphase) and that for the uranium richest samples a second phase formed, with an orthorhombic structure (α phase). For the U-Zr-Gd alloys the X-ray diffractometry revealed the retention of a hexagonal structure (δ phase) and gadolinium traces in the poorest uranium samples. The U{sub 57}(Zr{sub 92}Gd{sub 8}){sub 43} sample resulted monophasic becoming, according to literature, the first time that a solid solution combining uranium and gadolinium is identified. (author)

  18. Methodology of environmental evaluation of wastes stabilized/solidified by hydraulic binders; Methodologie d'evaluation environnementale des dechets stabilises / solidifies par liants hydrauliques

    Energy Technology Data Exchange (ETDEWEB)

    Imyim, A.

    2000-12-15

    The aim of this work is the formalization of a methodology of evaluation of the leaching behaviour of massive porous materials obtained by stabilization/solidification of wastes. In a first part, a set of simple leaching tests is proposed which allow the physico-chemical characterization of materials. In order to better understand the phenomena involved in the release process, the methodology has been applied to hydraulic binder-based and lead-bearing synthesized materials. In a second step, a mathematical model has been proposed for the description of the leaching behaviour. The development of the model is based on the observations and experimental results obtained with the synthesized materials. Finally, the methodology of evaluation of the leaching behaviour has been applied to two cases of real wastes: the fly ashes of a Danish municipal waste incineration facility, and the galvanic sludges from an industrial waste water processing facility from Netherlands. (J.S.)

  19. Evaluation of low and intermediate level radioactive solidified waste forms and packages

    International Nuclear Information System (INIS)

    1990-10-01

    Evaluation of low and intermediate level radioactive waste forms and packages with respect to compliance with quality and safety requirements for transport, interim storage and disposal has become a very important part of the radioactive waste management strategy in many countries. The evaluation of waste forms and packages provides precise basic data for regulatory bodies to establish safety requirements, and implement quality control and quality assurance procedures for radioactive waste management programmes. The requirements depend very much upon the disposal option selected, treatment technology used, waste form characteristics, package quality and other factors. The regulatory requirements can also influence the methodology of waste form/package evaluation together with selection and analysis of data for quality control and safety assurance. A coordinated research programme started at the end of 1985 and brought together 12 participants from 11 countries. The results of the programme and each particular project were discussed at three Research Coordination Meetings held in Cairo, Egypt, in May, 1986; in Beijing, China, in April, 1998; and at Harwell Laboratory, United Kingdom, in November, 1989. This document summarises the salient features and results achieved during the four year investigation and a recommendation for future work in this area. Refs, figs and tabs

  20. Analysis of environmental effects from disposal of solidified ICPP high-level wastes

    International Nuclear Information System (INIS)

    Chipman, N.A.; Simpson, G.G.; Lawroski, H.; Rodger, W.A.; Frendberg, R.L.

    1979-01-01

    This work is part of a comprehensive study to assess possible environmental impacts from six different options for managing high-level defense wastes generated at the ICPP. Only radiological consequences are considered in this report; population doses to those within 80 km of ICPP were estimated for time periods up to 100 million years. The population dose to future generations from any option is insignificant compared with that from natural background radiation: less than 1 cancer death in 1,000 years compared with 20,000 cancer deaths from natural background radiation. 16 tables

  1. Effects of solidified microstructures on J-R fracture resistances of the surge line pipe welds

    International Nuclear Information System (INIS)

    Youn, J. H.; Lee, B. S.; Yoo, W.

    2003-01-01

    The cause of the difference in J-R fracture resistances of AISI Type 347 GTAW welds which had almost same amounts of chromium carbides were investigated by the microstructural observations. As a result, the difference in the fracture resistances with the morphologies of the retained δ-ferrites in Type 347 welds were observed. The fracture resistance of the weld which had mostly vermicular type δ-ferrites was inferior to the weld which has lacy and acicular mixed type δ-ferrites. Therefore, it was deduced that the morphology of δ-ferrites affected the J-R fracture resistances of Type 347 welds

  2. Irradiation response of rapidly solidified Path A type prime candidate alloys

    International Nuclear Information System (INIS)

    Imeson, E.; Tong, C.; Lee, M.; Vander Sande, J.B.; Harling, O.K.

    1981-01-01

    The objective of this study is to present a first assessment of the microstructural response to neutron irradiation shown by Path A alloys prepared by rapid solidification processing. To more fully demonstrate the potential of the method, alloys with increased titanium and carbon content have been used in addition to the Path A prime candidate alloy

  3. Waste treatment process by solidifying cementitious materials using hydrothermal hot-pressing

    International Nuclear Information System (INIS)

    Matsumoto, Y.; Kamakura, T.; Yamasaki, N.; Hashida, T.

    2001-01-01

    Solidification of low-level radioactive wastes containing Na 2 SO 4 with cement by hydrothermal hot-pressing (HHP) technique was examined. Relatively high mechanical strength, reduced leaching ratio of SO 3 , and higher resistance to the carbonation of the HHP product were attained in comparison with conventional concrete. The solidification by the HHP treatment may be proceeded by the rearrangement of particles and the bonding material formation among the particles by dissolution-deposition process. The possibility of developing the accelerated testing method for duration of cemented materials by hydrothermal method was discussed. (author)

  4. SWEPP PAN assay system uncertainty analysis: Active mode measurements of solidified aqueous sludge waste

    International Nuclear Information System (INIS)

    Blackwood, L.G.; Harker, Y.D.; Meachum, T.R.

    1997-12-01

    The Idaho National Engineering and Environmental Laboratory is being used as a temporary storage facility for transuranic waste generated by the US Nuclear Weapons program at the Rocky Flats Plant (RFP) in Golden, Colorado. Currently, there is a large effort in progress to prepare to ship this waste to the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. In order to meet the TRU Waste Characterization Quality Assurance Program Plan nondestructive assay compliance requirements and quality assurance objectives, it is necessary to determine the total uncertainty of the radioassay results produced by the Stored Waste Examination Pilot Plant (SWEPP) Passive Active Neutron (PAN) radioassay system. This paper is one of a series of reports quantifying the results of the uncertainty analysis of the PAN system measurements for specific waste types and measurement modes. In particular this report covers active mode measurements of weapons grade plutonium-contaminated aqueous sludge waste contained in 208 liter drums (item description codes 1, 2, 7, 800, 803, and 807). Results of the uncertainty analysis for PAN active mode measurements of aqueous sludge indicate that a bias correction multiplier of 1.55 should be applied to the PAN aqueous sludge measurements. With the bias correction, the uncertainty bounds on the expected bias are 0 ± 27%. These bounds meet the Quality Assurance Program Plan requirements for radioassay systems

  5. Influence of fracture networks on radionuclide transport from solidified waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Seetharam, S.C., E-mail: suresh.seetharam@sckcen.be [Performance Assessments Unit, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, B-2400 Mol (Belgium); Perko, J.; Jacques, D. [Performance Assessments Unit, Institute for Environment, Health and Safety, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, B-2400 Mol (Belgium); Mallants, D. [CSIRO Land and Water, Waite Road – Gate 4, Glen Osmond, SA 5064 (Australia)

    2014-04-01

    Highlights: • Magnitude of peak radionuclide fluxes is less sensitive to the fracture network geometry. • Time of peak radionuclide fluxes is sensitive to the fracture networks. • Uniform flow model mimics a limiting case of a porous medium with large number of fine fractures. • Effect of fracture width on radionuclide flux depends on the ratio of fracture to matrix conductivity. • Effect of increased dispersivity in fractured media does not always result in a lower peak flux for specific fracture networks due to higher concentrations adjacent to the fracture plane. - Abstract: Analysis of the effect of fractures in porous media on fluid flow and mass transport is of great interest in many fields including geotechnical, petroleum, hydrogeology and waste management. This paper presents sensitivity analyses examining the effect of various hypothetical fracture networks on the performance of a planned near surface disposal facility in terms of radionuclide transport behaviour. As it is impossible to predict the initiation and evolution of fracture networks and their characteristics in concrete structures over time scales of interest, several fracture networks have been postulated to test the sensitivity of radionuclide release from a disposal facility. Fluid flow through concrete matrix and fracture networks are modelled via Darcy's law. A single species radionuclide transport equation is employed for both matrix and fracture networks, which include the processes advection, diffusion, dispersion, sorption/desorption and radioactive decay. The sensitivity study evaluates variations in fracture network configuration and fracture width together with different sorption/desorption characteristics of radionuclides in a cement matrix, radioactive decay constants and matrix dispersivity. The effect of the fractures is illustrated via radionuclide breakthrough curves, magnitude and time of peak mass flux, cumulative mass flux and concentration profiles. For the investigated system, radionuclide properties and the imposed water flow boundary conditions, results demonstrate that: (i) magnitude of peak radionuclide fluxes is less sensitive to the fracture network geometry, (ii) timing of the peak radionuclide fluxes is possibly sensitive to the fracture networks, (iii) a uniform flow model represents a limiting case of a porous medium with large number of fine fractures, (iv) the effect of fracture width on the radionuclide flux depends on the ratio of fracture to matrix conductivity and is less sensitive if the ratio is large and the width is higher than a certain critical size, and (v) increased dispersivity in fractured media influences the transport behaviour differently compared to non-fractured media; in particular, the behaviour depends on the nature of fracture network.

  6. Influence of fracture networks on radionuclide transport from solidified waste forms

    International Nuclear Information System (INIS)

    Seetharam, S.C.; Perko, J.; Jacques, D.; Mallants, D.

    2014-01-01

    Highlights: • Magnitude of peak radionuclide fluxes is less sensitive to the fracture network geometry. • Time of peak radionuclide fluxes is sensitive to the fracture networks. • Uniform flow model mimics a limiting case of a porous medium with large number of fine fractures. • Effect of fracture width on radionuclide flux depends on the ratio of fracture to matrix conductivity. • Effect of increased dispersivity in fractured media does not always result in a lower peak flux for specific fracture networks due to higher concentrations adjacent to the fracture plane. - Abstract: Analysis of the effect of fractures in porous media on fluid flow and mass transport is of great interest in many fields including geotechnical, petroleum, hydrogeology and waste management. This paper presents sensitivity analyses examining the effect of various hypothetical fracture networks on the performance of a planned near surface disposal facility in terms of radionuclide transport behaviour. As it is impossible to predict the initiation and evolution of fracture networks and their characteristics in concrete structures over time scales of interest, several fracture networks have been postulated to test the sensitivity of radionuclide release from a disposal facility. Fluid flow through concrete matrix and fracture networks are modelled via Darcy's law. A single species radionuclide transport equation is employed for both matrix and fracture networks, which include the processes advection, diffusion, dispersion, sorption/desorption and radioactive decay. The sensitivity study evaluates variations in fracture network configuration and fracture width together with different sorption/desorption characteristics of radionuclides in a cement matrix, radioactive decay constants and matrix dispersivity. The effect of the fractures is illustrated via radionuclide breakthrough curves, magnitude and time of peak mass flux, cumulative mass flux and concentration profiles. For the investigated system, radionuclide properties and the imposed water flow boundary conditions, results demonstrate that: (i) magnitude of peak radionuclide fluxes is less sensitive to the fracture network geometry, (ii) timing of the peak radionuclide fluxes is possibly sensitive to the fracture networks, (iii) a uniform flow model represents a limiting case of a porous medium with large number of fine fractures, (iv) the effect of fracture width on the radionuclide flux depends on the ratio of fracture to matrix conductivity and is less sensitive if the ratio is large and the width is higher than a certain critical size, and (v) increased dispersivity in fractured media influences the transport behaviour differently compared to non-fractured media; in particular, the behaviour depends on the nature of fracture network

  7. Simulations of Macrosegregation with consideration of inclusion effect in solidifying carbon steels

    International Nuclear Information System (INIS)

    Cao, Y F; Chen, Y; Kang, X H; Fu, P X; Liu, H W; Li, D Z

    2015-01-01

    During casting of steel ingots, the inclusions such as oxide, sulfide will inevitably exist in the melt. These inclusions will flow upward together with light solutes during solidification due to their lower density relative to the steel melt, which therefore causes impacts on the thermo-solutal convection in the melt and final solute distribution. Hence, a macrosegregation model that considers the effects of inclusions on melt flow in the mushy zone is established. Of the new model two important parameters, the inclusion capturing probability by solid, k p , and the original volume fraction, n 0 , are systematically studied in terms of simulations, which shows that decreasing k p or increasing n 0 leads to stronger ascending flow in the melt. And then as a validation example, the model was used to predict the macrosegregation in a 3.3-ton steel ingot. The prediction demonstrates that with consideration of inclusions, the melt convection strength is enhanced and thus the zones of macrosegregation are expanded comparing to simulations without taking account of inclusions. Further comparison with experiment results indicates that a better agreement of the carbon segregation along the centerline of the ingot can be achieved when considering the inclusion buoyancy. (paper)

  8. THE CHARACTERIZATION OF THE Ca-K GEOPOLYMER/SOLIDIFIED FLUID FLY-ASH INTERLAYER

    Directory of Open Access Journals (Sweden)

    Ivana Perna

    2016-12-01

    Full Text Available A Ca-K geopolymer matrix based on clay material and blast-furnace slag was filled with aggregates, ash pellets made from fluid fly ash, and the interlayer formed between the two components was studied. The scanning electron-microscopy investigation of the inseparable interlayer demonstrated that the pellets were not only enveloped in a geopolymer matrix but also incorporated through a thin, yet identifiable, surface pellet layer. The migration of calcium and potassium ions was detected and that changes in the quantity of these ions arise from their mobility. The interlayer on the edges of ash pellets was also studied by infrared analysis, which in this layer proved bands belonging to both participants, the matrix and the pellets. Based on the results, two different materials prepared from wastes could be used for the preparation of a new composite material and thus facilitate waste-material disposal.

  9. Properties of backfilling material for solidifying miscellaneous waste using recycled cement from waste concrete

    International Nuclear Information System (INIS)

    Matsuda, Atsuo; Yamamoto, Kazuo; Konishi, Masao; Iwamoto, Yoshiaki; Yoshikane, Toru; Koie, Toshio; Nakashima, Yoshio.

    1997-01-01

    A large reduction of total radioactive waste is expected, if recycled cement from the waste concrete of decommissioned nuclear power plants would be able to be used the material for backfilling mortar among the miscellaneous waste. In this paper, we discuss the hydration, strength and consistency of recycled cement compared with normal portland cement. The strength of recycled cement mortar is lower than that of normal portland cement mortar on the same water to cement ratio. It is possible to obtain the required strength to reduce the water to cement ratio by using of high range water-reducing AE agent. According to reducing of water to cement ratio, the P-type funnel time of mortar increase with the increase of its viscosity. However, in new method of self-compactability for backfilling mortar, it became evident that there was no difference between the recycled cement and normal portland cement on the self-compactability. (author)

  10. Assessing radioactive concentrates and waste vapor condensate in solidifying radioactive wastes by bituminization

    International Nuclear Information System (INIS)

    Tibensky, L.; Krejci, F.; Breza, M.; Timulak, J.; Hladky, E.

    1986-01-01

    A brief overview is presented of chemical and radiochemical methods used in the world for the analysis of the concentrate of liquid radioactive wastes from nuclear power plants destined for bituminization. Most methods are also suitable for an analysis of the condensate of waste vapors produced in bituminization. The methods of analysis of the radioactive concentrate from the V-1 nuclear power plant in Jaslovske Bohunice and of the waste vapors condensate were developed and tested in practice. Gross gamma activity was measured using a well-type Na(Tl) scintillation detector, the content of radionuclides was determined using semiconductor Ge(Li) spectrometry. The concentration of boric acid in the concentrate was determined by titration with mannite; in the condensate, using spectrophotometry with curcumine. The content of nitrates in both the concentrate and the condensate was determined spectrophotometrically using salicylic acid, the content of nitrites was determined by spectrophotometry using sulfanilic acid and α-naphthylamine. Carbonates and chlorides were determined by titration, sodium and potassium by flame photometry. The content of organic acids was measured by gravimetry of extracted methyl esters, the content of surfactants by spectrophotometry. Infrared spectrophotometry was used in determining hydrocarbons in the waste vapor condensate. The measured value range and the measurement errors are shown for each method. (A.K.)

  11. The characterization of the Ca–K geopolymer/solidified fluid fly-ash interlayer

    Czech Academy of Sciences Publication Activity Database

    Perná, Ivana; Šupová, Monika; Hanzlíček, Tomáš

    2017-01-01

    Roč. 61, č. 1 (2017), s. 26-33 ISSN 0862-5468 Institutional support: RVO:67985891 Keywords : fluid fly ash * blast-furnace slag * geopolymer * interlayer * recycling Subject RIV: DM - Solid Waste and Recycling OBOR OECD: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics Impact factor: 0.439, year: 2016 https://www.irsm.cas.cz/materialy/cs_content/2016_doi/Perna_CS_2016_0056.pdf

  12. Characterization of the Ni-45wt% Ti shape memory alloy rapidly solidified

    International Nuclear Information System (INIS)

    Anselmo, G.C.S.; Castro, W.B. de; Araujo, C.J. de

    2010-01-01

    One important challenge of microsystems design is the implementation of miniaturized actuation principles efficient at the micro-scale. Shape memory alloys (SMAs) have early on been considered as a potential solution to this problem as these materials offer attractive properties like a high-power to weight ratio, large deformation and the capability to be processed at the micro-scale. shape memory characteristics of Ni-45wt%Ti alloy ribbons prepared by melt spinning were investigated by means of differential scanning calorimetry and X-ray. In these experiments particular attention has been paid to change the velocity of cooling wheel from 30 to 50 m/s. Then the cooling rates of ribbons were controlled. The effect of this cooling rate on martensitic transformation behaviors and structure are discussed. (author)

  13. Thermal and microstructural analysis of an aluminium A356 alloy solidified by magnetic agitation

    International Nuclear Information System (INIS)

    Bustos, O; Ordonez, S; Jarami, Dario; Colas, R

    2008-01-01

    A magnetic agitation device was designed using a permanently rotating magnetic field, in order to study the effect of applying a variable magnetic field to agitate cast metals during the solidification process. The procedure used to verify the machine's functioning involved smelting and casting a predefined amount of A356 alloy in the device with and without the application of the magnetic field and then characterizing the material obtained with standard procedures of metallographic analysis. The results obtained show that the application of a permanently rotating magnetic field produces a destruction of the cast dendritic structure. This is explained by the fact that a magnetic field that varies over time induces a f.e.m. in a fluid conductor that becomes an increased convective transport through the Lorentz force. This work also studied the kinetics of solidification. The alloy was heated to 680 o C and was cast in molds preheated to 200 o C. Tests were carried out with and without the application of magnetic agitation. The cooling curves were recorded to evaluate the effect of the magnetic agitation on the alloy's form of solidification. The thermal analysis of the cooling curves shows a decrease in the temperatures under which the formation of dendrites from the primary phase as well as from the eutectic Al-Si phase begins when a magnetic field is imposed. A series of intermetallic AlFeSi type compounds appear in these alloys, which display noticeable refining and redistribution from the magnetic agitation (au)

  14. Elevated temperature mechanical properties of a rapidly solidified A1-Fe-V-Si alloy

    International Nuclear Information System (INIS)

    Mitra, S.

    1992-01-01

    Dispersion strengthened Al alloys based on the Al-Fe-V-Si quartenary system have recently been developed using rapid solidification techniques. Rapid solidification techniques which resulted in the above mentioned alloys have also been used to manufacture another commercial alloy, FVS 1212, with 37 volume % of dispersoid. The alloy has shown excellent resistance to coarsening at high temperatures and to creep deformation. Elevated temperature exposure of FVS 1212, for times up to 100 hours, resulted in a significant loss in room temperature mechanical properties only beyond 500 degrees C while 1000 hours at 425 degrees C did not result in any degradation of mechanical but no detailed study of the tensile behavior of FVS 1212 at slow strain rates and elevated temperatures has been reported to date. This paper reports that the present study was undertaken to investigate the tensile behavior of FVS 1212 from room temperature to 400 degrees C at strain rates of 6.56 x 10 - 5/sec and 6.56 x 10 -6 /sec. The study focussed on dynamic strain aging effects and strain hardening behavior, while the effect of strain rate on the flow behavior at elevated temperatures was also evaluated

  15. Field lysimeter facility for evaluating the performance of commercial solidified low-level waste

    International Nuclear Information System (INIS)

    Walter, M.B.; Graham, M.J.; Gee, G.W.

    1984-11-01

    Analyzing the potential migration of radionuclides from sites containing solid low-level wastes requires knowledge of contaminant concentrations in the soil solution surrounding the waste. This soil solution concentration is generally referred to as the source term and is determined by such factors as the concentration of radionuclides in the solid waste, the rate of leachate formation, the concentration of dissolved species in the leachate, any solubility reactions occurring when the leachate contacts the soil, and the rate of water flow in the soil surrounding the waste. A field lysimeter facility established at the Hanford site is being used to determine typical source terms in arid climates for commercial low-level wastes solidifed with cement, Dow polymer (vinyl ester-styrene), and bitumen. The field lysimeter facility consists of 10, 3-m-deep by 1.8-m-dia closed-bottom lysimeters situated around a 4-m-deep by 4-m-dia central instrument caisson. Commercial cement and Dow polymer waste samples were removed from 210-L drums and placed in 8 of the lysimeters. Two bitumen samples are planned to be emplaced in the facility's remaining 2 lysimeters during 1984. The central caisson provides access to the instrumentation in the individual lysimeters and allows selective sampling of the soil and waste. Suction candles (ceramic cups) placed around the waste forms will be used to periodically collect soil-water samples for chemical analysis. Meteorological data, soil moisture content, and soil temperature are automatically monitored at the facility. Characterization of the soils and waste forms have been partially completed. These data consist of moisture release characteristics, particle-size distribution, and distributions and concentrations of radionuclides in the waste forms. 11 references, 12 figures, 5 tables

  16. Certain aspects of leaching kinetics of solidified ''radioactive wastes'' - Laboratory studies

    International Nuclear Information System (INIS)

    Amarantos, S.G.; Petropoulos, J.H.

    1981-01-01

    A laboratory study of the kinetics of leaching of Cs + and Sr ++ incorporated as sulphates in cement (Portland type) or base asphalt with distilled water as leachant is reported. The comparison of different leaching methods (including stagnant or stirred leachant with periodic renewal and a new method of ''continuous leachant renewal'') and the study of the effect of temperature were among the particular objectives of this work. The results for the cemented salts indicate that the new method of ''continuous leachant renewal'' is more efficient than the others. Is has been also found that the other leaching methods, including the widely used stagnant, periodically renewed leachant, can be seriously affected in certain circumstances by factors which have hitherto been left uncontrolled. An observed sharp diminution in the elution rate of Sr ++ from cement samples appears to be attributable to the action of atmospheric CO 2 . It has been observed that temperature affects the acceleration in the earlier and later stages of cement-Cs 2 SO 4 leaching. (T.A.)

  17. Evolution of rapidly solidified NiAlCu(B) alloy microstructure.

    Science.gov (United States)

    Czeppe, Tomasz; Ochin, Patrick

    2006-10-01

    This study concerned phase transformations observed after rapid solidification and annealing at 500, 700 and 800 degrees C in 56.3 Ni-39.9 Al-3.8 Cu-0.06 B (E1) and 59.8 Ni-36.0 Al-4.3 Cu-0.06 B (E2) alloys (composition in at.%). Injection casting led to a homogeneous structure of very small, one-phase grains (2-4 microm in size). In both alloys, the phase observed at room temperature was martensite of L1(0) structure. The process of