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Sample records for rapidly solidified zrsub

  1. New developments in rapidly solidified magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.K. [Allied-Signal, Inc., Morristown, NJ (United States); Chang, C.F. [Allied-Signal, Inc., Morristown, NJ (United States); Raybould, D. [Allied-Signal, Inc., Morristown, NJ (United States); King, J.F. [Magnesium Elektron Ltd., Manchester (United Kingdom); Thistlethwaite, S. [Magnesium Elektron Ltd., Manchester (United Kingdom)

    1992-12-31

    In the present paper, we will examine the new developments in the rapidly solidified Mg-Al-Zn-Nd (EA55RS) alloy. We shall first briefly review the process scale-up currently employed for producing rapidly solidified magnesium alloys in large quantities, and then discuss the effect of billet size and processing parameters on the mechanical properties of various mill product forms such as extrusions and sheets. The superplastic behavior of EA55RS extrusions and rolled sheets are also discussed. Finally, some results on magnesium metal-matrix composites using rapidly solidified EA55RS matrix powders and SiC particulates are presented. (orig.)

  2. Testing techniques for mechanical characterization of rapidly solidified materials

    Science.gov (United States)

    Koch, C. C.

    1986-01-01

    Mechanical property testing techniques are reviewed for rapidly solidified materials. Mechanical testing of rapidly solidified materials is complicated by the fact that in most cases at least one dimension of the material is very small (less than 100 microns). For some geometries, i.e., powder or thin surface layers, microhardness is the only feasible mechanical test. The ribbon geometry which is obtained by the melt-spinning method, however, has been used for a variety of mechanical property measurements including elastic properties, tensile properties, fracture toughness, creep, and fatigue. These techniques are described with emphasis placed on the precautions required by the restricted geometry of rapidly solidified specimens.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    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...

  4. Microstructures in rapidly solidified Ni-Mo alloys

    Science.gov (United States)

    Jayaraman, N.; Tewari, S. N.; Hemker, K. J.; Glasgow, T. K.

    1986-01-01

    Ni-Mo alloys of compositions ranging from pure Ni to Ni-40 at. percent Mo were rapidly solidified by Chill Block Melt Spinning in vacuum and were examined by optical metallography, X-ray diffraction and transmission electron microscopy. Rapid solidification resulted in an extension of molybdenum solubility in nickel from 28 to 37.5 at. percent. A number of different phases and microstructures were seen at different depths (solidification conditions) from the quenched surface of the melt spun ribbons.

  5. Rapidly solidified Mg-Al-Zn-rare earth alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.F.; Das, S.K.; Raybould, D.

    1987-01-01

    Among the light metal alloys, magnesium is the lightest structural material except for beryllium, and yet magnesium alloys have not seen extensive use because of their poor strength and corrosion resistance. Rapid solidification technology offers a possible solution to these problems. A number of Mg-Al-Zn alloys containing rare earth (RE) elements (e.g. Ce, Pr, Y, and Nd) have been investigated using rapid solidification processing for possible structural applications. The processing consists of planar flow or jet casting into ribbons, pulverization of ribbon to powder, and consolidation of powder into bulk shapes. The mechanical properties of some of these alloys show attractive combinations of strength, ductility and corrosion resistance. The microstructures of these alloys are correlated with their mechanical properties. The rapidly solidified Mg-Al-Zn-RE alloys show great potential for applications in automotive and aerospace industries. 7 references.

  6. 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.

  7. 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)

  8. 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.

  9. Microstructure evolution and thermal stability of rapidly solidified Al-Ni-Co-RE alloy

    Directory of Open Access Journals (Sweden)

    B. Karpe

    2013-07-01

    Full Text Available In the frame of this work, Al-5Ni-1Co-3RE (RE-Rare Earth (Mischmetal rapidly solidified ribbons were manufactured and analyzed. The morphology of the as-cast structure, as well as the microstructural features were analyzed by transmission electron microscopy (TEM and scanning electron microscopy (SEM. Thermal stability has been investigated by combination of four point scanning electrical resistivity measurement (ER, differential scanning calorimetry (DSC and microhardness measurement. From the results we can conclude, that Al-5Ni-1Co-3RE rapidly solidified alloys have good thermal stability due to very slow coarsening kinetics of precipitated particles.

  10. Influence of quench rates on the properties of rapidly solidified ...

    Indian Academy of Sciences (India)

    Unknown

    A K PANDA, I CHATTORAJ, S BASU* and A MITRA. National Metallurgical Laboratory, Jamshedpur 831 007, India. *Materials Science Centre, Indian Institute of Technology, Kharagpur 721 302, India. Abstract. FeNbCuSiB based materials were produced in the form of ribbons by rapid solidification techniques.

  11. Influence of quench rates on the properties of rapidly solidified ...

    Indian Academy of Sciences (India)

    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 amorphous ...

  12. Phosphorus Segregation in Meta-Rapidly Solidified Carbon Steels

    Science.gov (United States)

    Li, Na; Qiao, Jun; Zhang, Junwei; Sha, Minghong; Li, Shengli

    2017-09-01

    Twin-roll strip casters for near-net-shape manufacture of steels have received increased attention in the steel industry. Although negative segregation of phosphorus occurred in twin-roll strip casting (TRSC) steels in our prior work, its mechanism is still unclear. In this work, V-shaped molds were designed and used to simulate a meta-rapid solidification process without roll separating force during twin roll casting of carbon steels. Experimental results show that no obvious phosphorus segregation exist in the V-shaped mold casting (VMC) steels. By comparing TRSC and the VMC, it is proposed that the negative phosphorus segregation during TRSC results from phosphorus redistribution driven by recirculating and vortex flow in the molten pool. Meanwhile, solute atoms near the advancing interface are overtaken and incorporated into the solid because of the high solidification speed. The high rolling force could promote the negative segregation of alloying elements in TRSC.

  13. The Development of Rapidly Solidified Magnesium – Copper Ribbons

    Directory of Open Access Journals (Sweden)

    Pastuszak M.

    2016-06-01

    Full Text Available The aim of the present work was to plan and carry out an experiment consisting of amorphization of industrial magnesium alloy WE 43 (Mg - 4 Y - 3 RE - 0.5 Zr modified by the copper addition. Investigated alloy modified with 20% of copper was rapidly quenched with the use of melt spinning technique. The effects of cooling rate on the structure and properties of the obtained material were extensively analyzed. The structure and phase analysis of samples were examined using X-ray diffraction method (XRD while the thermal stability of the samples was determined by differential scanning calorimetry (DSC. Microstructure observations were also conducted. The microhardness tests (HV0.02 and corrosion resistance tests were carried out to investigate the properties of the material. Corrosion resistance measurements were held using a typical three-electrode system. As the result of the research, the effect of cooling rate on microstructure and properties of investigated alloy was determined.

  14. Properties of rapidly solidified Al-12.5 Si-1Ni alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tawtik, N.L.; Abdel Hady, E.M.; Bastawros, A.M. [Nat. Res. Centre, Giza (Egypt). Solid State Phys. Dept.

    1998-11-01

    Rapidly solidified Al-12.5 Si-1 Ni ribbons were prepared by melt spinning. The Si solid solubility was extended to high values as deduced from X-ray diffraction and TEM. This high solubility of Si was found to have significant effects on the various properties of this alloy. High values of electric resistivity was observed which was about four times the fully annealed values. Furthermore rapid solidification improved the tensile strength and the toughness of this alloy as compared with its classically solidified counter part. The relaxation kinetics was followed by isothermal resistivity measurements. The relaxation follows an equation which has the Johnson-Mehl-Avrami (JMA) form. No metastable phase was observed. (orig.)

  15. Corrosion resistance of rapidly solidified Al-Cu and Al-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Girgis, N.N. (Corrosion Dept., Central Metallurgical Research and Development Inst., Helwan (Egypt)); Bastawros, A.M. (Physics Dept., National Research Center, Dokki, Giza (Egypt))

    1992-12-01

    This work has shown that rapidly solidified AlSi alloy is more resistant than AlCu when exposed in either neutral or acidic chloride solutions. This can be related to Si, metalloid element, which accelerates active dissolution of the alloy surface and causes rapid formation of a passive film and subsequent enrichment of Al in the film. This is in agreement with the views of Naka et al. on the role of metalloid elements, like phosphorus, in promoting the corrosion resistance of amorphous alloys. (orig.)

  16. Microstructure and mechanical properties of rapidly solidified FeAlCr intermetallic compound

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    R. A. Rodríguez‐Díaz

    2009-08-01

    Full Text Available In this work results regarding microstructural characterization of a melt‐spun intermetallic compound Fe40Al5Cr (% at.produced by rapid solidification employing the melt spinning technique at three different tangential wheel speeds (12, 16 and20 ms‐1 are presented. Melt spun ribbons were characterized by optical and scanning electron microscopy (SEM in order toobserve morphology, grain size, ribbon thickness and also fracture surfaces after tensile tests. EDS coupled to SEM wasemployed to perform punctual and scan line chemical analyses on samples, x‐ray diffraction (XRD was utilized to identify crystalstructure and phases. Transmission electron microscopy (TEM was employed to confirm crystal structure and also tocharacterize nanopores formed in the specimens by vacancy clustering. With regard to mechanical properties, micro hardnessVickers measurements as well as tensile tests at room temperature were applied to the rapidly solidified ribbons.The grain size of rapidly solidified Fe40Al5Cr ribbons suffered a drastic reduction as compared with alloys of the samecomposition produced by conventional melting and casting methods, and in melt‐spun ribbons it decreases as the wheel speedincreases. Punctual and line‐scanning chemical analyses revealed that Cr enters in solid solution in FeAl matrix. Hardnessmeasurements revealed a softening in rapidly solidified FeAlCr ribbons as compared with FeAl alloys and tensile test exhibited a(transgranular + intergranular mode of fracture, reaching up to 3 % of elongation in FeAlCr alloys. The presence of porous(meso and nano were also characterized.

  17. Undercooling of Rapidly Solidified Droplets and Spray Formed Strips of Al-Cu (Sc)

    Science.gov (United States)

    Bogno, A.; Natzke, P.; Yin, S.; Henein, H.

    Impulse Atomization (IA) (a single fluid atomization technique) was used to rapidly solidify Al-4.5wt%Cu and Al-4.5wt%Cu-0.4wt%Sc under argon atmosphere. In addition to the IA-generated droplets, the same technique was used to produce strips by Spray Deposition (SD) of the same alloys on a copper substrate with and without oil coating. The rapid solidification microstructures were analyzed using Scanning Electron Microscopy (SEM). From the SEM images, the amount of eutectic and the secondary dendrite arm spacing (SDAS) were measured. These SDAS results lead to the estimation of cooling rate. The eutectic fraction coupled with the metastable extension of the solidus and liquidus lines of Al-Cu (Sc) phase diagram lead to the estimation of primary and eutectic undercoolings. A comparison of the solidification path of the droplets and the strips was done as well as the analysis of the effects of scandium.

  18. Microstructure Properties of Rapidly Solidified Al-Zn-Mg-Cu Alloys

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    Emad M. Ahmed

    2014-01-01

    Full Text Available The Rietveld X-ray diffraction analysis was applied to analyze the weight fraction of precipitation phases and microstructure characterizations of rapidly solidified Al-8Zn-4Mg-xCu, x = 1, 4, 8, and 10 alloys (in wt.%, prepared by melt spun technique. A good agreement between observed and calculated diffraction pattern was obtained and the conventional Rietveld factors (Rp, Rwp, and GOF converged to satisfactory values. Solid solubilities of Zn, Mg, and Cu in α-Al were extended to high values. Besides, metastable Al0.71Zn0.29, intermetallic Al2CuMg, Al2Cu, and CuMgZn phases have been observed for x = 4, 8, and 10 Cu alloys. The crystal structure and microstructure characterizations exhibit strong Cu content dependence.

  19. Heat Treatment Development for a Rapidly Solidified Heat Resistant Cast Al-Si Alloy

    Science.gov (United States)

    Kasprzak, W.; Chen, D. L.; Shaha, S. K.

    2013-07-01

    Existing heat treatment standards do not properly define tempers for thin-walled castings that solidified with high solidification rates. Recently emerged casting processes such as vacuum high pressure die casting should not require long solution treatment times due to the fine microstructures arising from rapid solidification rates. The heat treatment studies involving rapidly solidified samples with secondary dendrite arm spacing between 10 and 35 μm were conducted for solution times between 30 min and 9 h and temperatures of 510 and 525 °C and for various aging parameters. The metallurgical analysis revealed that an increase in microstructure refinement could enable a reduction of solution time up to 88%. Solution treatment resulted in the dissolution of Al2Cu and Al5Mg8Si6Cu2, while Fe- and TiZrV-based phases remained partially in the microstructure. The highest strength of approximately 351 ± 9.7 and 309 ± 3.4 MPa for the UTS and YS, respectively, was achieved for a 2-step solution treatment at 510 and 525 °C in the T6 peak aging conditions, i.e., 150 °C for 100 h. The T6 temper did not yield dimensionally stable microstructure since exceeding 250 °C during in-service operation could result in phase transformation corresponding to the over-aging reaction. The microstructure refinement had a statistically stronger effect on the alloy strength than the increase in solutionizing time. Additionally, thermal analysis and dilatometer results were presented to assess the dissolution of phases during solution treatment, aging kinetics as well as dimensional stability.

  20. Microstructural observations and thermal stability of a rapidly solidified aluminum-gadolinium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Savage, S.J.; Eliezer, D.; Froes, F.H. (Rapid Solidification Group, Swedish Institute for Metals Research, Drottning Kristinas vag 48, S-114 28 Stockholm (SE))

    1987-08-01

    Rapid solidification processing has significant potential to extend the use of aluminum alloys to higher temperatures (200/sup 0/C to 350/sup 0/C). In particular, alloys based on Al-Fe-X compositions, where X = Ce or Mo, have been studied in detail. Cerium is representative of the family of rare earth, or lanthanide elements, and forms a number of intermetallic compounds with aluminum. Alloys containing rare earths other than cerium have received little attention, although for several reasons they are considered worthy of study. Rapidly solidified ribbons were prepared from this alloy by the chill block melt spinning technique at a peripheral wheel velocity of 20.4 m/s. A melt temperature of --1300/sup 0/C was used to ensure complete dissolution of all intermetallic particles. The ribbons produced were typically about 100 ..mu..m thick and 2 to 3 mm wide. Standard polishing techniques were used to prepare sections for optical microscopy and microhardness measurements. Room temperature Keller's reagent (diluted to 50 vol pct, in water) was used to etch the samples. Thin foils were prepared for TEM by electropolishing from both sides of the ribbon using the window technique.

  1. Surface precipitation of chromium in rapidly solidified Cu-Cr alloys

    Science.gov (United States)

    Bizjak, Milan; Karpe, Blaž; Jakša, Gregor; Kovač, Janez

    2013-07-01

    Rapidly solidified ribbons of Cu-Cr alloys with 2.27 and 4.20 at.% of chromium were produced using the melt-spinning method. Alloys were analyzed by electron microscopy for complete solubility of Cr in copper matrix. To avoid disturbing effects of Cr phase particles, the kinetics and the sequence of microstructural transformations during heating were analyzed only the sample with 2.27 at.% of chromium with complete Cr solubility in the copper matrix. We then investigated the precipitation process for this alloy that was subsequently heated at a constant rate. The increased solid solubility obtained allowed the extensive precipitation of a Cr-rich phase. The kinetics and the sequence of microstructural changes that occurred during the heating were analyzed using an in situ measurement of the electrical resistance. The quenched microstructure was analyzed at transition points using scanning and transmission electron microscopy. X-ray photoelectron spectroscopy, as a very surface-sensitive method, was applied to study the changes in the chemical composition of the surface for the Cu-Cr alloy ribbons in the temperature range 400-700 °C during an in situ heat treatment in an ultra-high vacuum. The results show a relatively rapid precipitation of chromium to the surface, which starts at 400 °C and is correlated with a change in the microstructure and the electrical resistance. The Cr-precipitation is faster at higher temperatures and follows the parabolic law. The resistivity results for the supersaturated binary alloy were analyzed using the Ozawa method to give an activation energy for the precipitation of 196 ± 10 kJ mol-1.

  2. Microstructure and Mechanical Properties of a Novel Rapidly Solidified, High-Temperature Al-Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Overman, Nicole R.; Mathaudhu, Suveen; Choi, Jung-Pyung; Roosendaal, Timothy J.; Pitman, Stan G.

    2016-02-12

    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, AlFe11.4Si1.8V1.6Mn0.9 (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 0.1-0.25µm whereas branching in the shot material was 0.5-1.0µm. 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 544.2MPa at room temperature and 298.0MPa 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.

  3. Magnetism-Structure Correlations during the ε→τ Transformation in Rapidly-Solidified MnAl Nanostructured Alloys

    Directory of Open Access Journals (Sweden)

    Felix Jiménez-Villacorta

    2014-01-01

    Full Text Available Magnetic and structural aspects of the annealing-induced transformation of rapidly-solidified Mn55Al45 ribbons from the as-quenched metastable antiferromagnetic (AF ε-phase to the target ferromagnetic (FM L10 τ-phase are investigated. The as-solidified material exhibits a majority hexagonal ε-MnAl phase revealing a large exchange bias shift below a magnetic blocking temperature TB~95 K (Hex~13 kOe at 10 K, ascribed to the presence of compositional fluctuations in this antiferromagnetic phase. Heat treatment at a relatively low annealing temperature Tanneal ≈ 568 K (295 °C promotes the nucleation of the metastable L10 τ-MnAl phase at the expense of the parent ε-phase, donating an increasingly hard ferromagnetic character. The onset of the ε→τ transformation occurs at a temperature that is ~100 K lower than that reported in the literature, highlighting the benefits of applying rapid solidification for synthesis of the rapidly-solidified parent alloy.

  4. Magnetism-Structure Correlations during the epsilon ->tau Transformation in Rapidly-Solidified MnAl Nanostructured Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Villacorta, F; Marion, JL; Oldham, JT; Daniil, M; Willard, MA; Lewis, LH

    2014-01-21

    Magnetic and structural aspects of the annealing-induced transformation of rapidly-solidified Mn55Al45 ribbons from the as-quenched metastable antiferromagnetic (AF) epsilon-phase to the target ferromagnetic (FM) L1(0) tau-phase are investigated. The as-solidified material exhibits a majority hexagonal epsilon-MnAl phase revealing a large exchange bias shift below a magnetic blocking temperature T-B similar to 95 K (H-ex similar to 13 kOe at 10 K), ascribed to the presence of compositional fluctuations in this antiferromagnetic phase. Heat treatment at a relatively low annealing temperature T-anneal approximate to 568 K (295 degrees C) promotes the nucleation of the metastable L1(0) tau-MnAl phase at the expense of the parent epsilon-phase, donating an increasingly hard ferromagnetic character. The onset of the epsilon ->tau transformation occurs at a temperature that is similar to 100 K lower than that reported in the literature, highlighting the benefits of applying rapid solidification for synthesis of the rapidly-solidified parent alloy.

  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. Evaluation of Ti(3)Si Phase Stability from Heat-Treated, Rapidly Solidified Ti-Si Alloys

    OpenAIRE

    COSTA, Alex Matos da Silva; de Lima, Gisele Ferreira; Rodrigues,Geovani; NUNES, Carlos Angelo; Coelho,Gilberto Carvalho; Suzuki, Paulo Atsushi

    2010-01-01

    Ti-base alloys containing significant amounts of silicon have been considered for high temperature structural applications. Thus, information concerning phase stability on the Ti-Si system is fundamental and there are not many investigations covering the phase stability of the Ti(3)Si phase, specially its dependence on oxygen/nitrogen contamination. In this work the stability of this phase has been evaluated through heat-treatment of rapidly solidified Ti-rich Ti-Si alloys at 700 A degrees C ...

  7. Dendrite growth morphologies in rapidly solidified Al-4.5wt.%Cu droplets

    Science.gov (United States)

    Bedel, M.; Reinhart, G.; Bogno, A.-A.; Nguyen-Thi, H.; Boller, E.; Gandin, Ch-A.; Henein, H.

    2016-03-01

    The impulse atomization process developed at the University of Alberta (Canada) enables metallic powders to be solidified with controlled process parameters and improved properties. In order to investigate the microstructure morphologies in droplets of Al- 4.5wt.%Cu alloys, three-dimensional reconstructions of several droplets are obtained by using synchrotron X-ray micro-tomography, allowing a visualization of the inner microstructure in three dimensions. The analysis of the reconstructed volumes reveals that a wide range of morphology, from highly branched to “finger-bundle”, can be obtained for different droplets of similar diameter and produced in the same batch. Unexpectedly for this alloy, microstructural features also indicate that the development of the dendrite arms (primary and of higher orders) occurs in most droplets along crystallographic axes, instead of the usual directions observed in conventional casting technologies.

  8. A Study on the Physical Properties and Interfacial Reactions with Cu Substrate of Rapidly Solidified Sn-3.5Ag Lead-Free Solder

    Science.gov (United States)

    Ma, Hai-Tao; Wang, Jie; Qu, Lin; Zhao, Ning; Kunwar, A.

    2013-08-01

    A rapidly solidified Sn-3.5Ag eutectic alloy produced by the melt-spinning technique was used as a sample in this research to investigate the microstructure, thermal properties, solder wettability, and inhibitory effect of Ag3Sn on Cu6Sn5 intermetallic compound (IMC). In addition, an as-cast Sn-3.5Ag solder was prepared as a reference. Rapidly solidified and as-cast Sn-3.5Ag alloys of the same size were soldered at 250°C for 1 s to observe their instant melting characteristics and for 3 s with different cooling methods to study the inhibitory effect of Ag3Sn on Cu6Sn5 IMC. Experimental techniques such as scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectrometry were used to observe and analyze the results of the study. It was found that rapidly solidified Sn-3.5Ag solder has more uniform microstructure, better wettability, and higher melting rate as compared with the as-cast material; Ag3Sn nanoparticles that formed in the rapidly solidified Sn-3.5Ag solder inhibited the growth of Cu6Sn5 IMC during aging significantly much strongly than in the as-cast material because their number in the rapidly solidified Sn-3.5Ag solder was greater than in the as-cast material with the same soldering process before aging. Among the various alternative lead-free solders, this study focused on comparison between rapidly solidified and as-cast solder alloys, with the former being observed to have better properties.

  9. Amorphous Phase Formation Analysis of Rapidly Solidified CoCr Droplets

    Science.gov (United States)

    Bogno, Abdoul-Aziz; Riveros, Carlos; Henein, Hani; Li, Delin

    2016-12-01

    This paper investigates amorphous phase formation and rapid solidification characteristics of a CoCr alloy. High cooling rate and high undercooling-induced rapid solidification of the alloy was achieved by impulse atomization in helium atmosphere. Two atomization experiments were carried out to generate powders of a wide size range from liquid CoCr at two different temperatures. Amorphous fraction and kinetic crystallization properties of impulse atomized powders were systematically quantified by means of differential scanning calorimetry. In addition, different but complementary characterization tools were used to analyze the powders microstructures. The fraction of amorphous phase within the investigated powders is found to be promoted by high cooling rate or smaller powder size. The critical cooling rate for amorphous phase formation, which is influenced by the oxygen content in the melt, is found to be 3 × 104 K s-1 and corresponds to a 160- µm-diameter powder atomized in helium. Hardness of the powders is found to follow a trend that is described by the Hall-Petch relation when a relatively high fraction of crystalline structures is present and decreases with the fraction of amorphous phase.

  10. Microstructure Evolution and Biodegradation Behavior of Laser Rapid Solidified Mg–Al–Zn Alloy

    Directory of Open Access Journals (Sweden)

    Chongxian He

    2017-03-01

    Full Text Available The too fast degradation of magnesium (Mg alloys is a major impediment hindering their orthopedic application, despite their superior mechanical properties and favorable biocompatibility. In this study, the degradation resistance of AZ61 (Al 6 wt. %, Zn 1 wt. %, remaining Mg was enhanced by rapid solidification via selective laser melting (SLM. The results indicated that an increase of the laser power was beneficial for enhancing degradation resistance and microhardness due to the increase of relative density and formation of uniformed equiaxed grains. However, too high a laser power led to the increase of mass loss and decrease of microhardness due to coarsened equiaxed grains and a reduced solid solution of Al in the Mg matrix. In addition, immersion tests showed that the apatite increased with the increase of immersion time, which indicated that SLMed AZ61 possessed good bioactivity.

  11. Biocompatibility of rapidly solidified magnesium alloy RS66 as a temporary biodegradable metal.

    Science.gov (United States)

    Willbold, Elmar; Kalla, Katharina; Bartsch, Ivonne; Bobe, Katharina; Brauneis, Maria; Remennik, Sergei; Shechtman, Dan; Nellesen, Jens; Tillmann, Wolfgang; Vogt, Carla; Witte, Frank

    2013-11-01

    Biodegradable magnesium-based alloys are very promising materials for temporary implants. However, the clinical use of magnesium-based alloys is often limited by rapid corrosion and by insufficient mechanical stability. Here we investigated RS66, a magnesium-based alloy with extraordinary physicochemical properties of high tensile strength combined with a high ductility and a homogeneous grain size of ~1 μm which was obtained by rapid solidification processing and reciprocal extrusion. Using a series of in vitro and in vivo experiments, we analyzed the biodegradation behavior and the biocompatibility of this alloy. In vitro, RS66 had no cytotoxic effects in physiological concentrations on the viability and the proliferation of primary human osteoblasts. In vivo, RS66 cylinders were implanted into femur condyles, under the skin and in the muscle of adult rabbits and were monitored for 1, 2, 3, 4 and 8 weeks. After explantation, the RS66 cylinders were first analyzed by microtomography to determine the remaining RS66 alloy and calculate the corrosion rates. Then, the implantation sites were examined histologically for healing processes and foreign body reactions. We found that RS66 was corroded fastest subcutaneously followed by intramuscular and bony implantation of the samples. No clinical harm with transient gas cavities during the first 6 weeks in subcutaneous and intramuscular implantation sites was observed. No gas cavities were formed around the implantation site in bone. The corrosion rates in the different anatomical locations correlated well with the local blood flow prior to implantation. A normal foreign body reaction occurred in all tissues. Interestingly, no enhanced bone formation could be observed around the corroding samples in the condyles. These data show that RS66 is biocompatible, and due to its interesting physicochemical properties, this magnesium alloy is a promising material for biodegradable implants. Copyright © 2013 Acta Materialia Inc

  12. Investigation of the effect of rapidly solidified braze ribbons on the microstructure of brazed joints

    Science.gov (United States)

    Bobzin, K.; Öte, M.; Wiesner, S.; Rochala, P.; Mayer, J.; Aretz, A.; Iskandar, R.; Schwedt, A.

    2017-03-01

    Shrinkage and warpage due to melting and solidification are crucial for the geometric precision of related components. In order to assure a high geometric precision, the formation of the microstructure in the joint during brazing must be taken into consideration. An extensive interaction can occur between liquid melt and base material, resulting in the formation of distinctive phases. This interaction depends on the parameters of the brazing process. However, the consequences of the interaction between phase formation and process parameters in terms of geometric precision cannot be estimated yet. Insufficient quality of the joint can be a result. In this study, investigations focus on the process of solidification in terms of time dependent diffusion behavior of elements. Therefore, microcrystalline and amorphous braze ribbons based on Ti are produced by rapid solidification and are used for joining. The microstructure of the braze ribbons as well as the melting behavior and phase formation during brazing are considered to be of particular importance for the mechanical properties of the brazed components.

  13. Improving permanent magnetic properties of rapidly solidified nanophase RE-TM-B alloys by compositional modification

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z.W. [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD (United Kingdom)], E-mail: zwliu@scut.edu.cn; Liu, Yan; Deheri, P.K.; Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Davies, H.A. [Department of Engineering Materials, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2009-08-15

    Rapid solidification is one of the most important techniques to produce nanocrystalline rare-earth-transition metal-boron (RE-TM-B) hard magnetic materials. To achieve high performance on these NdFeB-based alloys, compositional modification and microstructure optimization have been frequently employed. In this short review, various substitutions and doping elements have been discussed regarding to their behaviors in adjusting the individual or combined hard magnetic properties as well as the microstructure based on our recent results. It has been demonstrated that Pr and Dy enhance coercivity {sub j}H{sub C}, whereas Sm reduces {sub j}H{sub C} due to their effects on intrinsic properties. Co improves the thermal stability as well as the microstructure. Introducing Fe{sub 65}Co{sub 35} is a possible approach to enhance the magnetization and maximum energy product (BH){sub max}. As a doping element, Ta was found to play an important role to obtain an appropriate combination of magnetic properties for this type of alloys.

  14. Microstructures and properties of rapidly solidified Cu90Zr10-xAlx alloys

    Directory of Open Access Journals (Sweden)

    Bing-wen Zhou

    2016-07-01

    Full Text Available u90Zr10-xAlx (x=1, 3, 5, 7, 9; at.% alloy rods were synthesized based on rapid solidification method. The structure, distribution of elements, mechanical properties and electrical conductivity of the Cu-based alloy samples were studied using X-ray diffraction (XRD, scanning electron microscope (SEM, electro-probe micro-analyzer (EPMA, uniaxial compression test and four-probe technique. The as-cast Cu90Zr10-xAlx (x=1, 3, 5; at.% alloy rods with a diameter of 2 mm exhibit good mechanical properties and electrical conductivity, i.e., high compressive yield strength of 812-1513 MPa, Young’s modulus of 52-85 GPa, Vickers hardness of 250-420 and electrical conductivity of 11.1%-12.6% IACS (International Annealed Copper Standard. The composite microstructure composed of high density fibrous duplex structure (Cu5Zr and α-Cu phases is thought to be the origin of the high strength.

  15. Recovery Phenomenon During Annealing of an As-Rapidly Solidified Al Alloy

    Science.gov (United States)

    Yan, Zhigang; Mao, Shuaiying; Lin, Yaojun; Zhang, Yaqi; Wang, Limin

    2017-06-01

    It has been well documented that recovery occurring in metals/alloys produced via solid-state quenching involves only annihilation of supersaturated vacancies. Interestingly, in the present study, we observed completely different mechanisms underlying recovery during annealing of an Al-Zn-Mg-Cu (7075 Al) alloy processed via liquid-state quenching, i.e., rapid solidification (specifically melt spinning herein). The as-melt-spun alloy consists of refined grains containing tangled dislocations inside the grains. Following annealing at 393 K (120 °C) for 24 hours, refined grain structure was still retained and grain sizes essentially remained unchanged, but subgrains separated by dense dislocation walls were generated at grain interiors, with a much lower density of dislocations at subgrain interiors than that in the as-melt-spun 7075 Al alloy and dislocation arrays inside some subgrains. The microstructural evolution suggests the absence of recrystallization and the occurrence of recovery primarily via the annihilation and rearrangement of dislocations and the formation of subgrains. Based on the stored energy in dislocations in, and the annealing temperature of, the as-melt-spun 7075 Al alloy, the recovery phenomenon was analyzed and discussed in detail.

  16. 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 the formation of the Ni(5)Al(3) phase by atomic reordering proceeded at 285-394 degrees C in the case of E1 alloy and 450-550 degrees C in the case of E2 alloy. Further decomposition into NiAl (beta) and Ni(3)Al (gamma') phases, the microstructure and crystallography of the phases depended on the path of transformations, proceeding in the investigated case through the transformation of martensite crystallographic variants. This preserved precise crystallographic orientation between the subsequent phases, very stable plate-like morphology and very small beta + gamma' grains after annealing at 800 degrees C.

  17. Precipitate Evolution and Strengthening in Supersaturated Rapidly Solidified Al-Sc-Zr Alloys

    Science.gov (United States)

    Deane, Kyle; Kampe, S. L.; Swenson, Douglas; Sanders, P. G.

    2017-04-01

    Because of the low diffusivities of scandium and zirconium in aluminum, trialuminide precipitates containing these elements have been reported to possess excellent thermal stability at temperatures of 573 K (300 °C) and higher. However, the relatively low equilibrium solubilities of these elements in aluminum limit the achievable phase fraction and, in turn, strengthening contributions from these precipitates. One method of circumventing this limitation involves the use of rapid solidification techniques to suppress the initial formation of precipitates in alloys containing higher solute compositions. This work specifically discusses the fabrication of supersaturated Al-Sc, Al-Zr, and Al-Sc-Zr alloys via melt spinning, in which supersaturations of at least 0.55 at. pct Zr and 0.8 at. pct Sc are shown to be attainable through XRD analysis. The resulting ribbons were subjected to a multistep aging heat treatment in order to encourage a core-shell precipitate morphology, the precipitate evolution behavior was monitored with XRD and TEM, and the aging behavior was observed. While aging in these alloys is shown to follow similar trends to conventionally processed materials reported in literature, with phase fraction increasing until higher aging temperatures causing a competing dissolution effect, the onset of precipitation begins at lower temperatures than previously observed and the peak hardnesses occurred at higher temperature steps due to an increased aging time associated with increased solute concentration. Peaking in strength at a higher temperature doesn't necessarily mean an increase in thermal stability, but rather emphasizes the need for intelligently designed heat treatments to take full advantage of the potential strengthening of supersaturated Al-Sc-Zr alloys.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Effects of intermetallic phases on the electrochemical properties of rapidly-solidified Si-Cr alloys for rechargeable Li-ion batteries

    Science.gov (United States)

    Ha, Jeong Ae; Jo, In Joo; Park, Won-Wook; Sohn, Keun Yong

    2016-09-01

    The microstructures and the electrochemical properties of rapidly-solidified Si-Cr alloys of various compositions were investigated in order to elucidate the effects of intermetallic phases on the cyclic energy capacity of the materials. Rapidly-solidified ribbons of the alloys were prepared by using a melt-spinning process, which is one of the most efficient rapid-solidification processes. The ribbons were fragmented by using a ball-milling process to produce powders of the alloys. To examine the electrochemical characteristics of the alloys, we mixed each of the alloy powders with Ketjenblack®, a conductive material, and a binder dissolved in deionized water and used it to form electrodes. The electrolyte used was 1.5-M LiPF6 dissolved in ethyl carbonate/dimethyl carbonate/fluoroethylene carbonate. The microstructures and the phases of the alloys were analyzed by using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analyses. The obtained results showed that the microstructures of the rapidly-solidified Si-Cr alloys were composed of Si and CrSi2 phases. Fine Si particles with diameters of 50 - 100 nm were observed in an eutectic constituent while the sizes of the primary Si and CrSi2 phases were relatively larger at 500 - 900 nm. The specific energy capacities ( C) of the Si-Cr alloys decreased linearly with increasing volume fraction ( f) of the CrSi2 phase as follows: C = -1,667 f + 1,978 after the 50th cycle. The Columbic efficiency after the 3rd cycle increased slightly with increasing volume fraction of the CrSi2 phase; this was effective in improving the cycling capacity of the Si particles.

  3. Selective aluminum dissolution as a means to observe the microstructure of nanocrystalline intermetallic phases from Al-Fe-Cr-Ti-Ce rapidly solidified alloy.

    Science.gov (United States)

    Michalcová, Alena; Vojtěch, Dalibor; Novák, Pavel

    2013-02-01

    Rapidly solidified aluminum alloys are promising materials with very fine microstructure. The microscopy observation of these materials is complicated due to overlay of fcc-Al matrix and different intermetallic phases. A possible way to solve this problem is to dissolve the Al matrix. By this process powder formed by single intermetallic phase particles is obtained. In this paper a new aqueous based dissolving agent for Al-based alloy is presented. The influence of oxidation agent (FeCl(3)) concentration on quality of extraction process was studied. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Rapidly solidified Ag-Cu eutectics: A comparative study using drop-tube and melt fluxing techniques

    Science.gov (United States)

    Yu, Y.; Mullis, A. M.; Cochrane, R. F.

    2016-03-01

    A comparative study of rapid solidification of Ag-Cu eutectic alloy processed via melt fluxing and drop-tube techniques is presented. A computational model is used to estimate the cooling rate and undercooling of the free fall droplets as this cannot be determined directly. SEM micrographs show that both materials consist of lamellar and anomalous eutectic structures. However, below the critical undercooling the morphologies of each are different in respect of the distribution and volume of anomalous eutectic. The anomalous eutectic in flux- undercooled samples preferentially forms at cell boundaries around the lamellar eutectic in the cell body. In drop-tube processed samples it tends to distribute randomly inside the droplets and at much smaller volume fractions. That the formation of the anomalous eutectic can, at least in part, be suppressed in the drop-tube is strongly suggestive that the formation of anomalous eutectic occurs via remelting process, which is suppressed by rapid cooling during solidification.

  5. Room-Temperature Indentation Creep and the Mechanical Properties of Rapidly Solidified Sn-Sb-Pb-Cu Alloys

    Science.gov (United States)

    Kamal, Mustafa; El-Bediwi, A.; Lashin, A. R.; El-Zarka, A. H.

    2016-05-01

    In this paper, we study the room-temperature indentation creep and the mechanical properties of Sn-Sb-Pb-Cu alloys. Rapid solidification from melt using the melt-spinning technique is applied to prepare all the alloys. The experimental results show that the magnitude of the creep displacement increases with the increase in both time and applied load, and the stress exponent increases with the increase in the copper content in the alloys which happens primarily due to the existence of the intermetallic compounds SbSn and Cu6Sn5. The calculated values of the stress exponent are in the range of 2.82 to 5.16, which are in good agreement with the values reported for the Sn-Sb-Pb-Cu alloys. We have also studied and analyzed the structure, elastic modulus, and internal friction of the Sn-Sb-Pb-Cu alloys.

  6. Quantification of Primary Dendritic and Secondary Eutectic Nucleation Undercoolings in Rapidly Solidified Hypo-Eutectic Al-Cu Droplets

    Science.gov (United States)

    Bogno, A.-A.; Khatibi, P. Delshad; Henein, H.; Gandin, Ch.-A.

    2016-09-01

    This paper reports on the quantification of primary dendritic and secondary eutectic nucleation undercoolings during rapid solidification of impulse atomized hypo-eutectic Al-Cu droplets. The procedure consists in determining the eutectic fraction of each investigated droplet from the fraction of intermetallic Al2Cu obtained by Rietveld refinement analysis of neutrons scattering data. The corresponding eutectic nucleation undercooling is then deduced from the metastable phase diagram of the alloy. The primary dendritic nucleation undercooling is subsequently determined using semi-empirical coarsening models of secondary dendrite arms. The two nucleation undercoolings are finally used as input variables to run a microsegregation model for binary alloys. The fractions of eutectic computed by the microsegregation model compare very favorably with the experimental results.

  7. 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.

  8. 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.

  9. Hydrogen-induced changes in the crystalline structure and mechanical properties of a Zn-Al eutectoid alloy rapidly solidified

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval Jimenez, Alberto; Iturbe Garcia, Jose Luis [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: alberto.sandoval@inin.gob.mx; asandovalj@correo.unam.mx; Negrete Sanchez, Jesus [Universidad Autonoma de San Luis Potosi, San Luis Potosi (Mexico); Torres Villasenor, Gabriel [Instituto de Investigaciones en Materiales, UNAM, Mexico D.F. (Mexico)

    2009-09-15

    Ribbon fractions of a zinc-aluminum eutectoid (Zn40.8Al%at.) alloy, obtained by rapid solidification using melt spinning technique, were submitted to a thermo-hydrogenation process by periods of 1, 6, 18, 24, 30, and 48 hours, to 200 degrees Celsius and 20 atmospheres. Thermo-hydrogenated samples were analyzed by transmission electron microscopy (TEM). Hydrogen-induced changes were produced, such as microstructure refining, development of crystalline defects, microhardness changes and modification of stable crystalline structures to {alpha}R meta-stable phase at room temperature. [Spanish] Fracciones de tiras de una aleacion eutectoide de zinc-aluminio (Zn40.8Al%at.), obtenidas mediante solidificacion rapida usando la tecnica de melt spinning, se sometieron a un proceso de termohidrogenacion por periodos de 1, 6, 18, 24, 30 y 48 horas, a 200 grados centigrados y 20 atmosferas. Las muestras termohidrogenadas se analizaron por microscopia electronica de transmision (MET). Se produjeron cambios inducidos por hidrogeno, tales como la refinacion de la microestructura, el desarrollo de defectos cristalinos, cambios de microdureza y modificacion de las estructuras cristalinas estables a fase metaestable {alpha}R a temperatura ambiente.

  10. Application of Rapidly Solidified Superalloys.

    Science.gov (United States)

    1976-08-01

    from high speed cinematography , the liquid metal dwell time was cut from a period on the order of 80 milliseconds to one less than 10 milliseconds...formation theory, in which a liquid film is disintegrated directly into droplets, anticipates an exponent on_ on the order of 1, still below the values

  11. Liquid Phase Separation and the Aging Effect on Mechanical and Electrical Properties of Laser Rapidly Solidified Cu100−xCrx Alloys

    Directory of Open Access Journals (Sweden)

    Song-Hua Si

    2015-11-01

    Full Text Available Duplex structure Cu-Cr alloys are widely used as contact materials. They are generally designed by increasing the Cr content for the hardness improvement, which, however, leads to the unfavorable rapid increase of the electrical resistivity. The solidification behavior of Cu100−xCrx (x = 4.2, 25 and 50 in wt.% alloys prepared by laser rapid solidification is studied here, and their hardness and electrical conductivity after aging are measured. The results show that the Cu-4.2%Cr alloy has the most desirable combination of hardness and conductive properties after aging in comparison with Cu-25%Cr and Cu-50%Cr alloys. Very importantly, a 50% improvement in hardness is achieved with a simultaneous 70% reduction in electrical resistivity. The reason is mainly attributed to the liquid phase separation occurring in the Cu-4.2%Cr alloy, which introduces a large a

  12. Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al-5Mg-Mn Alloys Solidified Under Near-Rapid Cooling.

    Science.gov (United States)

    Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

    2016-01-29

    Mn was an important alloying element used in Al-Mg-Mn alloys. However, it had to be limited to a low level (alloy with low Fe content (alloys (0.5 wt % Fe), intermetallic Al₆(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al₆(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al₆(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al₆(Fe,Mn) to become the primary phase at a lower Mn content.

  13. Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al–5Mg–Mn Alloys Solidified Under Near-Rapid Cooling

    Science.gov (United States)

    Liu, Yulin; Huang, Gaoren; Sun, Yimeng; Zhang, Li; Huang, Zhenwei; Wang, Jijie; Liu, Chunzhong

    2016-01-01

    Mn was an important alloying element used in Al–Mg–Mn alloys. However, it had to be limited to a low level (alloy with low Fe content (alloys (0.5 wt % Fe), intermetallic Al6(Fe,Mn) became the dominant phase, even in the alloy with low Mn content (0.39 wt %). Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al6(Fe,Mn) was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al6(Fe,Mn) phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al6(Fe,Mn) to become the primary phase at a lower Mn content. PMID:28787888

  14. Inducing magnetic anisotropy and optimized microstructure in rapidly solidified Nd-Fe-B based magnets by thermal gradient, magnetic field and hot deformation

    Science.gov (United States)

    Zhao, L. Z.; Li, W.; Wu, X. H.; Hussain, M.; Liu, Z. W.; Zhang, G. Q.; Greneche, J. M.

    2016-10-01

    Direct preparation of Nd-Fe-B alloys by rapid solidification of copper mold casting is a very simple and low cost process for mini-magnets, but these magnets are generally magnetically isotropic. In this work, high coercivity Nd24Co20Fe41B11Al4 rods were produced by injection casting. To induce magnetic anisotropy, temperature gradient, assisted magnetic field, and hot deformation (HD) procedures were employed. As-cast samples showed non-uniform microstructure due to the melt convection. The thermal gradient during solidification led to the formation of radially distributed acicular hard magnetic grains, which gives the magnetic anisotropy. The growth of the oriented grains was confirmed by phase field simulation. A magnetic field up to 1 T applied along the casting direction could not induce significant magnetic anisotropy, but it improved the magnetic properties by reducing the non-uniformity and forming a uniform microstructure. The annealed alloys exhibited high intrinsic coercivity but disappeared anisotropy. HD was demonstrated to be a good approach for inducing magnetic anisotropy and enhanced coercivity by deforming and refining the grains. This work provides an alternative approach for preparing fully dense Nd-rich anisotropic bulk Nd-Fe-B magnets.

  15. Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al–5Mg–Mn Alloys Solidified Under Near-Rapid Cooling

    Directory of Open Access Journals (Sweden)

    Yulin Liu

    2016-01-01

    Full Text Available Mn was an important alloying element used in Al–Mg–Mn alloys. However, it had to be limited to a low level (<1.0 wt % to avoid the formation of coarse intermetallics. In order to take full advantage of the benefits of Mn, research was carried out to investigate the possibility of increasing the content of Mn by studying the effect of cooling rate on the formation of Fe- and Mn-rich intermetallics at different content levels of Mn and Fe. The results indicated that in Al–5Mg–Mn alloy with low Fe content (<0.1 wt %, intermetallic Al6(Fe,Mn was small in size and amount. With increasing Mn content, intermetallic Al6(Fe,Mn increased, but in limited amount. In high-Fe-containing Al–5Mg–Mn alloys (0.5 wt % Fe, intermetallic Al6(Fe,Mn became the dominant phase, even in the alloy with low Mn content (0.39 wt %. Cooling rate played a critical role in the refinement of the intermetallics. Under near-rapid cooling, intermetallic Al6(Fe,Mn was extremely refined. Even in the high Mn and/or high-Fe-containing alloys, it still demonstrated fine Chinese script structures. However, once the alloy composition passed beyond the eutectic point, the primary intermetallic Al6(Fe,Mn phase displayed extremely coarse platelet-like morphology. Increasing the content of Fe caused intermetallic Al6(Fe,Mn to become the primary phase at a lower Mn content.

  16. Effect of vanadium substitution for zirconium on the glass forming ability and mechanical properties of a Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Khademian, Nima, E-mail: nkhademian@gmail.com [Department of Mechanics, Islamshahr Branch, Islamic Azad University (IAU), Tehran (Iran, Islamic Republic of); Gholamipour, Reza [Iranian Research Organization for Science and Technology (IROST), Tehran (Iran, Islamic Republic of); Shahri, Farzad; Tamizifar, Morteza [Faculty of Engineering and High-Tech., Iran University of Industries and Mines (IUIM), Tehran (Iran, Islamic Republic of)

    2013-01-05

    Highlights: Black-Right-Pointing-Pointer The addition of V is effective for a decrease in GFA of Zr-based BMGs. Black-Right-Pointing-Pointer Mechanical properties of Zr-based BMGs are enhanced largely due to V addition. Black-Right-Pointing-Pointer Correlations among the elastic moduli, fracture strength, Vicker's hardness and glass transition for Zr-based BMGs. Black-Right-Pointing-Pointer Critical resolved shear stress ({tau}) of the Zr{sub 65-x}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5}V{sub x} alloys decreases with the increase of V content. - Abstract: Effect of vanadium on the thermal and mechanical properties of the Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass has been studied. The vanadium substitution for zirconium in the bulk metallic glass leads to the decrease of the glass forming ability in constant cooling rate; as well as co-precipitation of Zr{sub 2}Ni and Zr{sub 2}Cu crystalline phases in amorphous matrix. The size of the crystallites are about 20-50 nm in amorphous matrix and they act as a barrier against of rapid propagation of shear bands. In fact, the nanocrystalline phases in amorphous matrix cause the increase of the strain and the quasi-static compression strength about 58% and 20%, respectively.

  17. PAHs leaching test for solidified waste

    Energy Technology Data Exchange (ETDEWEB)

    Henzler, R.; Grathwohl, P. [Tuebingen Univ. (Germany). Center for Applied Geoscience

    2003-07-01

    The treatment of waste materials to allow recycling or safe disposal is a rapidly expanding business, but also subject to increasing public awareness of enviromental issues and tightening of the regularise governing in many countries. One of the most widely used treatment for wastes is stabilisation /solidification using a cement matrix to obtain a monolithic residue. The most common test procedure to assess the risks of contaminant release into water (seepage, surface and groundwater) is the so-called ''tank leaching test'' or ''diffusion test'' (NEN 7345, Mulder et al 2001, Hohberg et al 2000), in which a solidified specimen is leached with water during different periods of time. The tests are usually done at room temperatures between 20 C and 25 C. However, the temperature under natural conditions are lower resulting in lower contaminant release rates. (subsurface temperature: 5 C - 10 C). If the thermodynamics of the contaminant release, especially the activation energy of desorption and diffusion, is known, it is possible to estimate the contaminant release for lower temperatures, e.g. down to groundwater temperatures. In addition the test can be accelerated if performed at high temperatures.

  18. Characterization of Solidifiers used for Oil Spill Remediation

    Science.gov (United States)

    The physical characteristics and chemical composition of oil spill solidifiers were studied, and correlation of these properties with product effectiveness enabled determination of characteristics that are desirable in a good solidifier. The analyses revealed that the commercial...

  19. Thermal gradient analysis of solidifying casting

    Directory of Open Access Journals (Sweden)

    J. Suchoń

    2008-08-01

    Full Text Available For description of casting solidification and crystallization process the thermal derivative analysis (TDA is commonly used. Besides the process kinetics considered in TDA method to describe the solidification process, the thermal gradient analysis can be also used for this purpose [1, 2]. In conducted studies analysis of thermal gradient distribution inside the solidifying wedge casting was shown which enabled determination of heat flow intensity on casting section.

  20. Preparation, Characterization and Properties of Rapidly Solidified Alloys

    Science.gov (United States)

    1986-10-01

    the overlapping melt spots used to refine the surface microstructure. Figure 11. A crystal of the same type as shown in Figure 12, but aligned with a...rows there is a spacing of spots which follows a Fibonacci sequence for some distance until a defect is encountered; normal to the rows we then have...Gaussian. The fit shown corresponds to two overlapping Gaussians (see Table III). Fig. 4. SEM photographs of the edge of a flake with x - 0.20. The

  1. 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.

  2. Application of solidifiers for oil spill containment: A review.

    Science.gov (United States)

    Motta, Fernanda L; Stoyanov, Stanislav R; Soares, João B P

    2018-03-01

    The need for new and/or improvement of existing oil spill remediation measures has increased substantially amidst growing public concern with the increased transportation of unconventional crudes, such as diluted bitumen products. Solidifiers may be a very good spill response measure to contain and mitigate the effects of oil discharge incidents, as these interact with the oil to limit hydrocarbon release into air and water, prevent it from adhering onto sediment and debris, and could allow for oil recovery and reuse. Solidifiers change the physical state of the spilled oil from liquid to a coherent mass by chemical interactions between the spilled oil and the solidifier. Currently, the use of solidifiers is limited to small spills near shorelines. To extend their use to large-scale spill containment operations, it is necessary to understand the mechanism of solidifier action and to establish consistent criteria for evaluation of their effectiveness. The research effort to date has been focused mainly on gelators and cross-linking agents, with particularly impressive advancements in the areas of phase-selective polymeric and small-molecule gelators. Substantial research efforts are needed to improve solidifier performance and integrate solidifiers as part of spill response procedures, particularly for acute oil spills involving unconventional petroleum products. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  3. Application of Sorbents and Solidifiers for Oil Spills

    Science.gov (United States)

    This guide assists product manufacturers and members of the response community in distinguishing a sorbent from a solidifier for purposes of listing such products on the National Contingency Plan (NCP) Product Schedule and applying them in the field.

  4. Gusev Rocks Solidified from Lava (3-D)

    Science.gov (United States)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin. Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy. The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks. As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography to identify rocks and

  5. Gusev Rocks Solidified from Lava (False Color)

    Science.gov (United States)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin. Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy. The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks. As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography to identify rocks and

  6. 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.

  7. 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.

  8. Low-cost directionally-solidified turbine blades, volume 1

    Science.gov (United States)

    Sink, L. W.; Hoppin, G. S., III; Fujii, M.

    1979-01-01

    A low cost process of manufacturing high stress rupture strength directionally-solidified high pressure turbine blades was successfully developed for the TFE731-3 Turbofan Engine. The basic processing parameters were established using MAR-M 247 and employing the exothermic directional-solidification process in trial castings of turbine blades. Nickel-based alloys were evaluated as directionally-solidified cast blades. A new turbine blade, disk, and associated components were then designed using previously determined material properties. Engine tests were run and the results were analyzed and compared to the originally established goals. The results showed that the stress rupture strength of exothermically heated, directionally-solidified MAR-M 247 turbine blades exceeded program objectives and that the performance and cost reduction goals were achieved.

  9. Robust half-metallic properties in inverse Heusler alloys composed of 4d transition metal elements: Zr{sub 2}RhZ (Z=Al, Ga, In)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.T.; Lin, T.T. [School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130 (China); Rozale, H. [Condensed Matter and Sustainable Development Laboratory, Physics Department, University of Sidi-Bel-Abbès, 22000 Sidi-Bel-Abbès (Algeria); Dai, X.F., E-mail: xuefangdai1976@163.com [School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130 (China); Liu, G.D., E-mail: gdliu1978@126.com [School of Material Sciences and Engineering, Hebei University of Technology, Tianjin 300130 (China)

    2016-03-15

    A first-principles approach is used to study the electronic and magnetic properties of Zr{sub 2}RhZ (Z=Al, Ga, In) alloys in the Hg{sub 2}CuTi-type structure. The Zr{sub 2}RhZ (Z=Al, Ga, In) alloys are found to be half-metallic ferrimagnets. The half-metallicity is quite robust against hydrostatic strain and tetragonal deformation in Zr{sub 2}RhZ (Z=Al, Ga, In) alloys. The magnetization of Zr{sub 2}RhZ (Z=Al, Ga, In) alloys mainly originates from the 4d electrons of Zr atoms and follows the rule: M{sub t}=Z{sub t}−18. Zr{sub 2}Rh-based alloys do not contain any 3d transition metal element, which implies a wider field to search for new half-metallic materials. - Highlights: • Some HM materials containing 4d transition metal elements, Zr{sub 2}RhZ, have been found. • Zr{sub 2}RhZ alloys are HM ferrimagnets at their equilibrium lattice constants. • Their half-metallicity is robust against hydrostatic and tetragonal strains. • Zr{sub 2}RhZ with the Hg{sub 2}CuTi-type structure follows the SP rule M{sub t}=Z{sub t}−18. • Our results may trigger Zr-based HM materials applying in future spintronics field.

  10. Mechanical Properties of a Partially Solidified Cu-Zn Alloy

    Science.gov (United States)

    Kasuya, Naoki; Nakazawa, Tomoaki; Matsushita, Akira; Okane, Toshimitsu; Yoshida, Makoto

    2016-04-01

    For predicting solidification cracking by thermal stress analysis, the mechanical properties in the partially solidified state based on the experimental results are the best hope. However, the Young's modulus has never been investigated for copper alloys. In this study, stress-strain curves of a Cu-Zn alloy in the partially solidified state for various solid fractions were obtained using a specially developed horizontal tensile test device. Furthermore, by removing the load during the tensile test, the spring-back (elastic behavior) was observed and the Young's modulus was obtained.

  11. Thermal stability of nanocrystalline Pd{sub 81}Zr{sub 19}

    Energy Technology Data Exchange (ETDEWEB)

    VanLeeuwen, Brian K., E-mail: brian.vanleeuwen@gmail.com [Room 3000, Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC 27695-7907 (United States); Darling, Kristopher A. [Battelle, RDRL-WMM-B, Aberdeen Proving Ground, MD 21005-5069 (United States); Koch, Carl C.; Scattergood, Ron O. [Room 3000, Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC 27695-7907 (United States); Butler, Brady G. [Booz Allen Hamilton, RDRL-WMM-B, Aberdeen Proving Ground, MD 21005-5069 (United States)

    2010-07-15

    Grain growth stability in mechanically alloyed nanocrystalline Pd{sub 81}Zr{sub 19} was investigated. Previous research suggested that the alloy is thermodynamically stable to very high temperatures. When X-ray diffraction (XRD) is used to estimate the grain size of annealed samples the alloy appears to have remarkable resistance to growth. Microscopy done here on the same alloy indicated that the XRD estimates are not accurate for samples annealed above 600 deg. C. It appears that when this alloy is annealed at high temperatures XRD peak broadening is retained for reasons that are unrelated to the grain size. The alloy still has much improved grain growth stability compared with pure Pd, but not as significant as suggested by the XRD results. A similar phenomenon was observed in Fe-Zr alloys.

  12. High-temperature investigations of the rare earth NZP phosphates R {sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} (R = La, Nd, Eu, Lu) by drop calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, D.M. [Chemical Department, Nizhni Novgorod State University, Gagarin Ave. 23, 603950 Nizhni Novgorod (Russian Federation) and European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany)]. E-mail: denis.bykov@inbox.ru; Konings, R.J.M. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Orlova, A.I. [Chemical Department, Nizhni Novgorod State University, Gagarin Ave. 23, 603950 Nizhni Novgorod (Russian Federation)

    2007-07-31

    The high-temperature enthalpy increments of the phosphates La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3}, Nd{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3}, Eu{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} and Lu{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} have been measured by high-temperature drop calorimetry in the temperature range 484.5-1090.7 K. From these results the heat capacity of the studied compounds has been derived.

  13. Solidified reverse micellar solutions (SRMS): A novel approach for ...

    African Journals Online (AJOL)

    AMARA

    lipids based drug delivery systems. Salome Amarachi Chime* and Ikechukwu V. Onyishi. Department of Pharmaceutical Technology and Industrial Pharmacy, University of Nigeria, Nsukka 410001, Nigeria. Accepted 24 December, 2013. Solidified reverse micellar solutions (SRMS) are reverse micelles containing lecithin ...

  14. Solidified reverse micellar solutions (SRMS): A novel approach for ...

    African Journals Online (AJOL)

    Solidified reverse micellar solutions (SRMS) are reverse micelles containing lecithin and a triglyceride, for example, SOFTISAN®142, which is hydrogenated coco glyceride. SRMS transform into a lamellar mesophase after melting on contact with water; this transformation enables controlled release of solubilized drugs.

  15. Site suitability criteria for solidified high level waste repositories

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-03-07

    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. (JRD)

  16. Application of solidified sea bottom sediments into environmental bioremediation materials

    Directory of Open Access Journals (Sweden)

    Ahmed H.A. Dabwan

    2017-05-01

    Full Text Available Since dredged sea bottom sediments normally give off a horrible smell, the limitation of disposal places has become a serious problem in Japan. Hence, development of an alternative system to readily treat dredged sea bottom sediments is therefore needed. The development of “value-added” reused products from these sediments offers particular benefits both in terms of resource recovery and protection of the environment. We developed an in situ solidification system for the treatment of sea bottom sediments, the “Hi-Biah-System (HBS”. Firstly, this review deals with solidified sea bottom sediments for the construction of an artificial tidal flat in Ago Bay, Japan. The environmental conditions (pH, oxidation–reduction potential (ORP, acid volatile sulphide (AVS, loss on ignition (LOI, water content (WC, chemical oxygen demand (COD, total organic carbon (TOC, total nitrogen (T-N, chlorophyll a and particle size were then monitored in the constructed tidal flat. The number of benthos individuals and growth of short-necked clams (Ruditapes philippinarum in the artificial tidal flat were also evaluated. The environmental conditions, number of benthos individuals and growth of short-necked clams in the artificial tidal flat were shown to be similar to those observed in a natural tidal flat. Next, the potential use of solidified sea bottom sediments as soil parent material in the germination/growth of seagrass is presented. The soil parent material consisting of solidified sediments obtained using HBS plus soil conditioner and hardener seems to be effective for the germination of Zostera marina. The best growth after six months was observed in plants grown in soil parent material consisting of a mixture of solidified sediments and the sand by weight ration 70:30. The present study may suggest the possible application of solidified sea bottom sediments into growth of other plants.

  17. Rapid screening of potential metallic glasses for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C.H. [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Huang, C.H. [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Chuang, J.F. [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Huang, J.C., E-mail: jacobc@mail.nsysu.edu.tw [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Jang, J.S.C. [Institute of Materials Science and Engineering, Department of Mechanical Engineering, National Central University, Chung-Li, Taiwan, ROC (China); Chen, C.H. [Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC (China); Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC (China); Orthopedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC (China)

    2013-12-01

    This paper presents a rapid screening process to select potential titanium and zirconium based metallic glasses (MGs) for bio-material applications. Electrochemical activity of 7 MGs including 6 bulk metallic glasses and 1 thin-film deposited MG in simulation body and human serum is first inspected. A low-voltage potential state test is also developed to simulate the cell membrane potential that the implant MGs will suffer. Results show that the MGs composed of Ti{sub 65}Si{sub 15}Ta{sub 10}Zr{sub 10} and Ta{sub 57}Zr{sub 23}Cu{sub 12}Ti{sub 8} exhibit excellent electrochemical stability in both simulation body fluid and human serum. In addition, the copper content in the MGs plays an important role on the electrochemical activity. MGs with the copper content higher than 17.5% show significant electrochemical responses. The cytotoxicity of the solid MG samples and the corrosion released ions are also evaluated by an in-vitro MTT test utilizing the murine bone marrow stem cells. Results indicate that all the solid MG samples show no acute cytotoxicity yet the corrosion released ions show significant toxicity for murine bone marrow stem cells. The rapid screening process developed in the present study suggests that the Ti{sub 65}Si{sub 15}Ta{sub 10}Zr{sub 10} metallic glass has high potential for biomedical applications due to its good electrochemical stability and very low cytotoxicity. - Highlights: • A rapid electrochemical cycle screening process is proposed. • This process can select potential metallic glasses for bio-material applications. • The Ti{sub 65}Si{sub 15}Ta{sub 10}Zr{sub 10} metallic glass exhibits the best response and high potential.

  18. 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

  19. Microstructure evolution of directionally solidifi ed Sn-16%Sb hyperperitectic alloy

    Directory of Open Access Journals (Sweden)

    Li Shuangming

    2008-11-01

    Full Text Available The directionally solidifi ed microstructure of Sn-16%Sb hyperperitectic alloy has been investigated at various solidifi cation rates using a high-thermal gradient directional solidifi cation apparatus. The results indicate that the solidifi cation microstructure consists of hard primary intermetallic SnSb phase embedded in a matrix of soft peritectic β-Sn phase. The primary SnSb phase exhibits faceted growth with tetragonal or trigonal shapes. At the same time, the primary SnSb phase is refi ned with an increase in the solidifi cation rate and dispersed more uniformly in the matrix of β-Sn phase. The volume fraction of the SnSb phase fi rstly decreases and then increases when the solidifi cation rate increases in directional solidifi cation of Sn-16%Sb hyperperitectic alloy.

  20. Crystal clear transparent lipstick formulation based on solidified oils.

    Science.gov (United States)

    De Clermont-Gallerande, H; Chavardes, V; Zastrow, L

    1999-12-01

    We have developed a lipstick, the stick of which looks totally transparent. The base, coloured or not, may contain high concentration of actives or fragrances. The present study examines the process of determination of oils and solidifying agents. The selecting criterion include visible spectroscopic measurements to quantify transparency of the formulated product. We have also validated the stick hardness through drop point and breakage measurements. After several investigations, we selected a mixture of oils and solidifying agents. The oil network obtained has been characterized through optical microscopy, transmission electronic microscopy, X-ray diffraction and differential scanning calorimetry. We can show that the final product we obtained is amorphous and its solidity can be explained by chemical bonds formation.

  1. 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.

  2. Amorphous ribbons consolidation of Cu{sub 46}Zr{sub 42}Al{sub 7}Y{sub 5} alloy by hot extrusion; Consolidacao de fitas amorfas da liga The Cu{sub 46}Zr{sub 42}Al{sub 7}Y{sub 5} alloy with amorphous structure shows a temperature rangepor extrusao a quente

    Energy Technology Data Exchange (ETDEWEB)

    Melle, A.K.; Bolfarini, C.; Botta Filho, W.J.; Kiminami, C.S. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Peres, M.M., E-mail: anakarla13_8@hotmail.co [Universidade Federal de Itajuba (UNIFEI), Itabira, MG (Brazil)

    2010-07-01

    The Cu{sub 46}Zr{sub 42}Al{sub 7}Y{sub 5} alloy with amorphous structure shows a temperature range between the glass transition temperature (Tg) and the crystallization temperature (Tx) of Tx-Tg={Delta}T{sub x}= 100K. At this temperature range, the metal behavior is of a supercooled liquid with viscosity {approx_equal} 10{sup 6} N.s/m{sup 2}. The aim of this work is to contribute on the development of a processing route to produce bulk metallic glass. Amorphous ribbons was produced by rapid quenching using 'melt spinning' process, the ribbons were fragmented in small pieces, compacted at room temperature and consolidated by hot extrusion under extrusion temperatures on the {Delta}T{sub x}, ram speed of 1mm/min and extrusion ratio of 3:1. The extruded samples were characterized by X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results showed that extrusion temperature was fundamental to promote a full or partial consolidation of the amorphous ribbons, but causing the formation of some voids and inducing some regions to crystallization that showing the high sensibility to fit the extrusion temperature.(author)

  3. 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.

  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. 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

  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. (abstract) Undercooling Studies of the Bulk Metallic Glass Forming Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) Alloy During Containerless Electrostatic Levitation Processing

    Science.gov (United States)

    Kim, Y. J.; Busch, R.; Johnson, W. L.; Rulison, A. J.; Rhim, W. K.

    1995-01-01

    Bulk glass forming metallic alloys have long been desired for technological applications and for investigation into liquid undercooling, solidification processes, and thermophysical properties. A glass forming alloy Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) was used to investigate the thermal treatments affecting undercooling and vitrification. The experiments were performed using the high temperature high vacuum electrostatic levitator at JPL. A sample approximately 3 mm in diameter was melted, superheated, undercooled, and solidified while levitated in high vacuum. The results show that when the sample was held above its melting temperature for a sufficient period of time to dissolve oxides and then cooled faster than a critical cooling rate, it undercooled to the glass transition temperature, T(sub g), and formed a glassy alloy. The required critical cooling rate for metallic glass formation was obtained to be between 0.9 K per second and 1.2 K per second for the 42.4 mg sample.

  8. First principle investigations of the structural, electronic and magnetic properties of predicted new zirconium based full-Heusler compounds, Zr{sub 2}MnZ (Z=Al, Ga and In)

    Energy Technology Data Exchange (ETDEWEB)

    Birsan, A., E-mail: anca_birsan@infim.ro [National Institute of Materials Physics, 105 bis Atomistilor Street, PO Box MG-7, 077125 Magurele-Ilfov (Romania); University of Bucharest, Faculty of Physics, 105 Atomistilor Street, PO Box MG-11, 077125, Magurele-Ilfov (Romania); Kuncser, V. [National Institute of Materials Physics, 105 bis Atomistilor Street, PO Box MG-7, 077125 Magurele-Ilfov (Romania)

    2016-05-15

    The crystal structure, electronic and magnetic properties of predicted new full-Heusler compounds Zr{sub 2}MnZ (Z=Al, Ga, In) were studied within the density functional theory (DFT) framework. These materials exhibit unique properties that connect the spin gapless semiconducting character with the completely compensated ferrimagnetism. Magnetically ordered Zr{sub 2}MnZ (Z=Al, Ga, In) compounds crystallize in inverse Heusler structure are stable against decomposition and have zero magnetic moment per formula unit, in agreement with Slater–Pauling rule. The Zr{sub 2}MnAl compound presents semiconducting properties with an energy band gap of 0.41 eV in the majority spin channel and a zero band gap in the minority spin channel. By substituting completely the Al in Zr{sub 2}MnAl via Ga and In elements, semiconducting pseudo band gaps are formed in the majority spin channels due to different neighborhoods around the manganese atoms, which decreases the energy of Mn triple degenerated anti-bonding states. - Highlights: • Zr{sub 2}MnZ (Z=Al, Ga, In) compounds exhibit zero magnetic moments per formula unit, in the ground state. • Zr{sub 2}MnAl exhibits spin gapless semiconducting properties. • Zr{sub 2}MnZ (Z=Ga, In) presents semiconducting pseudo band gaps, around Fermi level.

  9. 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)

  10. Molecular dynamics studies of short to medium range order in Cu{sub 64}Zr{sub 36} metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Sha, Z.D., E-mail: shaz@ihpc.a-star.edu.sg [Institute of High Performance Computing, 1 Fusionopolis Way, Singapore 138632 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Zhang, Y.W. [Institute of High Performance Computing, 1 Fusionopolis Way, Singapore 138632 (Singapore); Feng, Y.P. [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Li, Y. [Department of Materials Science and Engineering, National University of Singapore, Engineering Drive 1, Singapore 117576 (Singapore)

    2011-08-18

    Highlights: > Short- and medium-range orders in Cu{sub 64}Zr{sub 36} metallic glass were investigated. > We employed the concept of core-shell rather than cluster packing. > The basic atomic structure has the characteristics of an icosahedral shell structure. > This finding applies to short- and medium-range orders in the optimum glass former. - Abstract: For metallic glasses, the cluster packing scheme addresses mainly the low solute concentration regime and it breaks down beyond a length scale of a few clusters. In the present work, from the viewpoint of core-shell structure rather than cluster packing, short- and medium-range orders in Cu{sub 64}Zr{sub 36} metallic glass were investigated using the large-scale atomic/molecular massively parallel simulator. In the first three coordination shells, the total number of atoms within the nth coordination shell is 13, 61, and 169. And the number of atoms on the nth coordination shell is 12n{sup 2}. Besides, the basic atomic structure could be obtained from a central icosahedron surrounded by a shell of 12n{sup 2} atoms. From the fourth coordination shell on, the total number of atoms is 307, 561, and 924, respectively, consistent with that in an icosahedral shell structure. Our finding suggests that for the optimum glass former in the Cu-Zr binary system, the basic atomic structures over both short- and medium-range length scales have the characteristics of an icosahedral shell structure.

  11. A study of reduced chromium content in a nickel-base superalloy via element substitution and rapid solidification processing. Ph.D. ThesisFinal Report

    Science.gov (United States)

    Powers, William O.

    1987-01-01

    A study of reduced chromium content in a nickel base superalloy via element substitution and rapid solidification processing was performed. The two elements used as partial substitutes for chromium were Si and Zr. The microstructure of conventionally solidified materials was characterized using microscopy techniques. These alloys were rapidly solidified using the chill block melt spinning technique and the rapidly solidified microstructures were characterized using electron microscopy. The spinning technique and the rapidly solidified microstructures was assessed following heat treatments at 1033 and 1272 K. Rapidly solidified material of three alloys was reduced to particulate form and consolidated using hot isostatic pressing (HIP). The consolidated materials were also characterized using microscopy techniques. In order to evaluate the relative strengths of the consolidated alloys, compression tests were performed at room temperature and 1033 K on samples of as-HIPed and HIPed plus solution treated material. Yield strength, porosity, and oxidation resistance characteristics are given and compared.

  12. 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}.

  13. Barrier efficiency of sponge-like La{sub 2}Zr{sub 2}O{sub 7} buffer layers for YBCO-coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Molina, Leopoldo; Tan, Haiyan; Biermans, Ellen; Verbeeck, Jo; Bals, Sara; Tendeloo, Gustaaf Van [EMAT, University of Antwerp, Groenenborgerlaan 171, BE-2020 Antwerp (Belgium); Batenburg, Kees J, E-mail: leopoldo.molina-luna@ua.ac.be [Vision Lab, University of Antwerp, Universiteitsplein 1, BE-2020 Wilrijk (Belgium)

    2011-06-15

    Solution derived La{sub 2}Zr{sub 2}O{sub 7} films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La{sub 2}Zr{sub 2}O{sub 7}, but different film processing methods can yield similar microstructural features such as nanovoids and nanometer-sized La{sub 2}Zr{sub 2}O{sub 7} grains. Nanoporosity is a typical feature found in such films and the implications for the functionality of the films are investigated by a combination of scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) and quantitative electron tomography. Chemical solution based La{sub 2}Zr{sub 2}O{sub 7} films deposited on flexible Ni-5 at.%W substrates with a {l_brace}100{r_brace}(001) biaxial texture were prepared for an in-depth characterization. A sponge-like structure composed of nanometer-sized voids is revealed by high-angle annular dark-field scanning transmission electron microscopy in combination with electron tomography. A three-dimensional quantification of nanovoids in the La{sub 2}Zr{sub 2}O{sub 7} film is obtained on a local scale. Mostly non-interconnected highly faceted nanovoids compromise more than one-fifth of the investigated sample volume. The diffusion barrier efficiency of a 170 nm thick La{sub 2}Zr{sub 2}O{sub 7} film is investigated by STEM-EELS, yielding a 1.8 {+-} 0.2 nm oxide layer beyond which no significant nickel diffusion can be detected and intermixing is observed. This is of particular significance for the functionality of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} coated conductor architectures based on solution derived La{sub 2}Zr{sub 2}O{sub 7} films as diffusion barriers.

  14. 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.

  15. Impact of mechanical stress on ferroelectricity in (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shiraishi, Takahisa [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Katayama, Kiliha; Yokouchi, Tatsuhiko; Oikawa, Takahiro [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Shimizu, Takao [Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Sakata, Osami [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Japan Synchrotron Radiation Research Institute (JASRI), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Uchida, Hiroshi [Department of Materials and Life Sciences, Sophia University, Chiyoda, Tokyo 102-8554 (Japan); Imai, Yasuhiko [Japan Synchrotron Radiation Research Institute (JASRI), Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Kiguchi, Takanori; Konno, Toyohiko J. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Funakubo, Hiroshi, E-mail: funakubo.h.aa@m.titech.ac.jp [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan); Department of Materials Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)

    2016-06-27

    To investigate the impact of mechanical stress on their ferroelectric properties, polycrystalline (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films were deposited on (111)Pt-coated SiO{sub 2}, Si, and CaF{sub 2} substrates with thermal expansion coefficients of 0.47, 4.5, and 22 × 10{sup −6}/ °C, respectively. In-plane X-ray diffraction measurements revealed that the (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films deposited on SiO{sub 2} and Si substrates were under in-plane tensile strain and that their volume fraction of monoclinic phase decreased as this strain increased. In contrast, films deposited on CaF{sub 2} substrates were under in-plane compressive strain, and their volume fraction of monoclinic phase was the largest among the three kinds of substrates. The maximum remanent polarization of 9.3 μC/cm{sup 2} was observed for Pt/(Hf{sub 0.5}Zr{sub 0.5})O{sub 2}/Pt/TiO{sub 2}/SiO{sub 2}, while ferroelectricity was barely observable for Pt/(Hf{sub 0.5}Zr{sub 0.5})O{sub 2}/Pt/TiO{sub 2}/SiO{sub 2}/CaF{sub 2}. This result suggests that the in-plane tensile strain effectively enhanced the ferroelectricity of the (Hf{sub 0.5}Zr{sub 0.5})O{sub 2} thin films.

  16. Building towers, domes, and arches by self-organized solidifying flows

    Science.gov (United States)

    Chopin, Julien

    2013-03-01

    We demonstrate that a wide variety of delicate solid structures from slender towers to arches, and chiral pagodas can be created by simply pouring a mixture of grains and water on a liquid absorbing substrate [Phys. Rev. Lett. 107, 208304 (2011)]. The same suspension poured on a solid substrate would form a featureless puddle or a pile with an angle of repose. However, an absorbing substrate can quickly drain the liquid from the suspension, rapidly causing the solidification of the fluid into a mechanically stable structure. In a dripping regime, successive drops are observed to jam rapidly upon impact literally stacking on top of each other forming slender granular towers. In a jetting regime and using a moving substrate, the jet is found to bounce on and off the substrate forming regular arches. We will discuss the subtle interplay of the incoming flux of the granular suspension, the drainage efficiency of the substrate, and the mechanical properties of the solid structure. The drainage driven jamming of granular suspensions gives a new route to shape cohesive granular materials and, from a broader perspective, demonstrates the potential a solidifying fluid spreading on a substrate to create new morphologies harder to achieve by other techniques. Applications to surface patterning, rheology of dense suspension and mechanics of wet granular materials will be discussed.

  17. 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.

  18. 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 Bi35In48.6Sn16Zn0.4 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 Bi35In48.6Sn16Zn0.4 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.

  19. Particle Trapping and Banding in Rapid Colloidal Solidification

    KAUST Repository

    Elliott, J. A. W.

    2011-10-11

    We derive an expression for the nonequilibrium segregation coefficient of colloidal particles near a moving solid-liquid interface. The resulting kinetic phase diagram has applications for the rapid solidification of clay soils, gels, and related colloidal systems. We use it to explain the formation of bandlike defects in rapidly solidified alumina suspensions. © 2011 American Physical Society.

  20. 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.

  1. Macrostructure evolution in directionally solidified Mg-RE alloys

    Science.gov (United States)

    Salgado-Ordorica, M. A.; Punessen, W.; Yi, S.; Bohlen, J.; Kainer, K. U.; Hort, N.

    The use of Rare-Earths (RE) to develop new cast- and wrought-magnesium alloys has acquired increased interest in recent years. The good mechanical properties of Mg-RE alloys at room temperature, and in particular their high strength at relatively high temperatures are at present well-known facts that make them very promising materials for transport applications. In this context, it is necessary to achieve a better understanding of the macro and microstructure evolution of cast Mg-metals directionally solidified. To this end, binary Mg-RE alloys (where RE = Gd, Nd and Y) were cast by permanent mould direct chill casting. This process was performed in a specially optimized laboratory-scale installation in order to ensure the obtention of "clean" ingots, with homogeneous composition and free of porosity and inclusions. A set of different processing conditions was evaluated in order to better control the final microstructure, mainly in terms of grain size, orientation and distribution. The grain selection mechanisms operating during the solidification of these specimens, namely texturization and Columnar to Equiaxed Transition (CET), were characterized and put into relation with the initial composition of the alloy and the imposed cooling conditions.

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

    National Research Council Canada - National Science Library

    Hu Wen; Duo Zhang; Zhijin Yu; Xuezhao Zheng; Shixing Fan; Bin Laiwang

    2017-01-01

    .... 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...

  3. The structure and properties of rapidly solidified high alloy aluminum materials

    Science.gov (United States)

    Grant, N. J.

    1982-01-01

    A series of 2024 type aluminum alloys modified by additions of 1 to 2% Li were studied to determine the role of the Cu:Li and the (Cu + Mg):Li ratios on resultant strength, ductility, notch-tensile behavior, and crack propagation rates. Ultrasonically gas atomized powders with quench rates of 10 to 100 thousand degrees/s were atomized in an argon atmosphere, producing yields of powder such that almost 100% was finer than 250 microns. The powders are free of gases and porosity, are quite spherical, have few satellites (adhering fine powder particles) and are of uniform microstructure. Strength properties are such that yield strength is 20% greater than for lithium-free 2024 ingot alloy, tensile strength is 10% greater than that of 2024 ingot material, and ductilities are comparable. In terms of specific strength and specific modulus, these RS 2024-Li alloys are significantly better than IM 2024.

  4. Sinterable Ceramic Powders from Laser Heated Gas Phase Reactions and Rapidly Solidified Ceramic Materials.

    Science.gov (United States)

    1984-07-01

    Gattuso, T. R., Meunier, M., Adler, D., and Haggerty, J. S., "IR Laser- Induced Deposition of Silicon Thin Films ", to be published in the Proceedings of...and Thin Films by Laser Induced Gas Phase Reactions", presented at the Nineteenth University Conference on Ceramic Science, Emergent Process Methods... Silicon Carbonitrides from Monomeric Organosilicon Precursors". To be presented at the 1983 Annual Meeting of the American Ceramic Society, April 1983

  5. Morphology and microstructure of rapidly solidified tin-lead alloy powders

    Directory of Open Access Journals (Sweden)

    Xiang Qingchun

    2014-09-01

    Full Text Available Sn60Pb40 alloy powders were fabricated using the planar flow casting (PFC atomization process. By using OM, SEM and EPMA, the characteristics of the morphologies and microstructures of the powders have been investigated. It is observed that the environment of ambient gas in the atomization box has great effects on the morphology of the alloy powders. The microstructures of Sn60Pb40 alloy powders produced by the PFC atomization process are completely composed of eutectic, which is made up of both oversaturated α solid solution and β solid solution. The microstructures of small size powders are extraordinarily undeveloped dendritic eutectic, in which the large majority of the α phase appears nearly spherical, evidently since the cooling rate is higher and the under-cooling is larger. As for the large size powders, since the cooling rate and undercooling are relatively low, lamellar α phase apparently increases in the eutectic microstructures of these powders, and there is even typical lamellar eutectic structure clearly observed in some micro-areas. After remelting tests by DTA, the microstructures of small size powders are transformed, which become composed of large crumby α phase and eutectic (α+β, while those of large size powders change into classical tin-lead structures of primary α phase plus lamellar eutectic (α+β. By studying the microstructures of tin-lead alloy powders, a model has been proposed to predict the microstructure formation of Sn60Pb40 alloy powders.

  6. Magnetocaloric properties of rapidly solidified Dy{sub 3}Co alloy ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez Llamazares, J. L., E-mail: jose.sanchez@ipicyt.edu.mx; Flores-Zúñiga, H.; Sánchez-Valdés, C. F. [Instituto Potosino de Investigación Científica y Tecnológica A.C., Camino a la Presa San José 2055 Col. Lomas 4" a, San Luis Potosí, S.L.P. 78216 (Mexico); Álvarez-Alonso, Pablo [Departamento de Electricidad y Electrónica, UPV/EHU, 48940 Leioa (Spain); Lara Rodríguez, G. A. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, México, D. F. 04510 (Mexico); Fernández-Gubieda, M. L. [Departamento de Electricidad y Electrónica, UPV/EHU, 48940 Leioa (Spain); BC Materials, Camino de Ibaizabal, Edificio 500, Planta 1, Parque Científico y Tecnológico de Zamudio, 48160 Derio (Spain)

    2015-05-07

    The magnetic and magnetocaloric (MC) properties of melt-spun ribbons of the Dy{sub 3}Co intermetallic compound were investigated. Samples were fabricated in an Ar environment using a homemade melt spinner system at a linear speed of the rotating copper wheel of 40 ms{sup −1}. X-ray diffraction analysis shows that ribbons crystallize into a single-phase with the Fe{sub 3}C-type orthorhombic crystal structure. The M(T) curve measured at 5 mT reveals the occurrence of a transition at 32 K from a first to a second antiferromagnetic (AFM) state and an AFM-to-paramagnetic transition at T{sub N} = 43 K. Furthermore, a metamagnetic transition is observed below T{sub N}, but the magnetization change ΔM is well below the one reported for bulk alloys. Below 12 K, large inverse MC effect and hysteresis losses are observed. This behavior is related to the metamagnetic transition. For a magnetic field change of 5 T (2 T) applied along the ribbon length, the produced ribbons show a peak value of the magnetic entropy change ΔS{sub M}{sup peak} of −6.5 (− 2.1) Jkg{sup −1}K{sup −1} occurring close to T{sub N} with a full-width at half-maximum δT{sub FWHM} of 53 (37) K, and refrigerant capacity RC = 364 (83) Jkg{sup −1} (estimated from the product |ΔS{sub M}{sup peak}| × δT{sub FWHM})

  7. The relation between experiments and modeling of rapidly solidified 12Cr-Mo-V stainless steel

    DEFF Research Database (Denmark)

    Pryds, Nini; Hattel, Jesper Henri

    1998-01-01

    Solidification during melt spinning of a 12Cr-Mo-V stainless steel has been experimentally studied and numerically simulated. The resulting microstructures have been related to the unknown parameter h, i.e. the heat transfer coefficient between the substrate and the melt, by fitting the heat flow...... of metastable austenite as the primary phase near the chill side of the ribbon. Upon quenching to room temperature, this austenite transformed into martensite. At a distance of about 15 mu m from the chill surface, the growth velocity of the solid/liquid interface decreased (

  8. Microstructure of rapidly solidified Nb-based pre-alloyed powders for additive manufacturing

    Science.gov (United States)

    Guo, Yueling; Jia, Lina; Kong, Bin; Zhang, Shengnan; Zhang, Fengxiang; Zhang, Hu

    2017-07-01

    For powder-based additive manufacturing, sphere-shaped Nb-37Ti-13Cr-2Al-1Si pre-alloyed powders were prepared by plasma rotating electrode processing (PREP). The microstructure, surface oxidation and microhardness of the pre-alloyed powders were systematically investigated. Results showed that the main phases were Nb solid solution (Nbss) and Cr2Nb. The Cr2Nb phases were further determined using transmission electron microscopy (TEM). Fine dendrite structures were observed in the as-fabricated pre-alloyed powders, which transformed to large grains after heat treatment (HT) at 1450 °C for 3 h. With the increase of powder size, the secondary dendrite arm spacing (SDAS) increased and the microhardness (HV) decreased. A clean powder surface free of oxide particles was obtained by PREP and an oxide layer with 9.39 nm in thickness was generated on the powder surface. Compared with Cr- and Nb-oxides, more Ti-oxides were formed on outmost powder surface with a higher content of Ti (up to 47.86 at.%). The differences upon the microstructure and microhardness of the pre-alloyed powders with different sizes were discussed.

  9. Quatification of Primary Phase Undercooling of Rapidly Solidified Droplets with 3D Microtomography

    Science.gov (United States)

    Ilbagi, A.; Khatibi, P. Delshad; Henein, H.; Gandin, Ch. A.; Herlach, D. M.

    Powders of different compositions of Al-Cu alloys were atomized in helium and nitrogen and the microstructure of the atomized droplets was examined using X-ray micro-tomography. A method was developed to remove X-ray artifacts and background noise from the particles images. The method developed involves creating a clean mask file using MATLAB image toolbox, followed by applying the mask file to the original image to achieve clean images for the particle of interest. Separate features of interest in the droplets, such as region of initial growth and primary dendrites, were investigated at the various stages of solidification. The data is used to estimate the primary phase undercooling of the droplets, which will be used in a solidification model as an input to estimate the phase fractions. The results will then be compared with the experimental results.

  10. Microstructure of rapidly solidified Nb-based pre-alloyed powders for additive manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yueling; Jia, Lina, E-mail: jialina@buaa.edu.cn; Kong, Bin; Zhang, Shengnan; Zhang, Fengxiang; Zhang, Hu

    2017-07-01

    Highlights: • Sphere shaped Nb-37Ti-13Cr-2Al-1Si pre-alloyed powders were prepared by PREP. • An oxide layer with a thickness of 9.39 nm was generated on the powder surface. • The main phases of the pre-alloyed powders were Nbss and Cr{sub 2}Nb. • SDAS increased and microhardness decreased with the increase of powder size. • Microstructure of powders evolved into large grains from dendrite structures after HT. - Abstract: For powder-based additive manufacturing, sphere-shaped Nb-37Ti-13Cr-2Al-1Si pre-alloyed powders were prepared by plasma rotating electrode processing (PREP). The microstructure, surface oxidation and microhardness of the pre-alloyed powders were systematically investigated. Results showed that the main phases were Nb solid solution (Nbss) and Cr{sub 2}Nb. The Cr{sub 2}Nb phases were further determined using transmission electron microscopy (TEM). Fine dendrite structures were observed in the as-fabricated pre-alloyed powders, which transformed to large grains after heat treatment (HT) at 1450 °C for 3 h. With the increase of powder size, the secondary dendrite arm spacing (SDAS) increased and the microhardness (HV) decreased. A clean powder surface free of oxide particles was obtained by PREP and an oxide layer with 9.39 nm in thickness was generated on the powder surface. Compared with Cr- and Nb-oxides, more Ti-oxides were formed on outmost powder surface with a higher content of Ti (up to 47.86 at.%). The differences upon the microstructure and microhardness of the pre-alloyed powders with different sizes were discussed.

  11. Microstructural evolution in a rapidly solidified Al-4mass%Fe droplet

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong-Gyoon (Department of Materials Science and Engineering, Kunsan National University, Kunsan 573-360 (Korea, Republic of)); Shin, Seong-Ho (Central Laboratory, Sammi Special Steel Company, Changwon 641-050 (Korea, Republic of)); Suzuki, Toshio (Engineering Research Institute, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113 (Japan)); Umeda, Takateru (Department of Metallurgy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113 (Japan))

    1994-05-15

    A two-dimensional non-newtonian numerical analysis on the solidification of Al-4mass%Fe droplet was represented which includes the transition between the partitionless and partitioned solidification modes. It was shown that, instead of the banded-structure formation, a strong instability on the macroscopic solid-liquid interface occurs in the transition range. The patterns predicted as functions of the initial undercooling and the droplet size were compared with the microstructures of the gas-atomized Al-4mass%Fe powders. ((orig.))

  12. Surface modification induced phase transformation and structure variation on the rapidly solidified recast layer of titanium

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Ming-Hung [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Haung, Chiung-Fang [School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Division of Family and Operative Dentistry, Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan (China); Shyu, Shih-Shiun [Department of Dentistry, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City 231, Taiwan (China); Chou, Yen-Ru [Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan (China); Graduate Institute of Biomedical Materials and Tissue Engineering, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Lin, Ming-Hong [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Peng, Pei-Wen, E-mail: apon@tmu.edu.tw [School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); and others

    2015-08-15

    In this study, neodymium-doped yttrium orthovanadate (Nd:YVO{sub 4}) as a laser source with different scanning speeds was used on biomedical Ti surface. The microstructural and biological properties of laser-modified samples were investigated by means of optical microscope, electron microscope, X-ray diffraction, surface roughness instrument, contact angle and cell cytotoxicity assay. After laser modification, the rough volcano-like recast layer with micro-/nanoporous structure and wave-like recast layer with nanoporous structure were generated on the surfaces of laser-modified samples, respectively. It was also found out that, an α → (α + rutile-TiO{sub 2}) phase transition occurred on the recast layers of laser-modified samples. The Ti surface becomes hydrophilic at a high speed laser scanning. Moreover, the cell cytotoxicity assay demonstrated that laser-modified samples did not influence the cell adhesion and proliferation behaviors of osteoblast (MG-63) cell. The laser with 50 mm/s scanning speed induced formation of rough volcano-like recast layer accompanied with micro-/nanoporous structure, which can promote cell adhesion and proliferation of MG-63 cell on Ti surface. The results indicated that the laser treatment was a potential technology to enhance the biocompatibility for titanium. - Highlights: • Laser induced the formation of recast layer with micro-/nanoporous structure on Ti. • An α → (α + rutile-TiO{sub 2}) phase transition was observed within the recast layer. • The Ti surface becomes hydrophilic at a high speed laser scanning. • Laser-modified samples exhibit good biocompatibility to osteoblast (MG-63) cell.

  13. Gusev Rocks Solidified from Lava (Approximate True Color)

    Science.gov (United States)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin. Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy. The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks. As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography to identify rocks and

  14. Thermophysical properties of Gd{sub 2}Zr{sub 2}O{sub 7} powders prepared by mechanical milling: Effect of homovalent Gd{sup 3+} substitution

    Energy Technology Data Exchange (ETDEWEB)

    Díaz-Guillén, J.A., E-mail: jadiaz@itsaltillo.edu.mx [División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Saltillo, 25280 Saltillo, Coahuila (Mexico); Durá, O.J. [GFMA, Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Díaz-Guillén, M.R. [Instituto de Investigaciones Eléctricas, 62490 Cuernavaca, Morelos (Mexico); Bauer, E. [Institute of Solid State Physics, Vienna University of Technology, Wien A-1040 (Austria); López de la Torre, M.A. [GFMA, Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Fuentes, A.F. [Cinvestav Unidad Saltillo, Apartado Postal 663, 25000 Saltillo, Coahuila (Mexico)

    2015-11-15

    This contribution analyzes the thermophysical properties of Gd{sub 1.6}Ln{sub 0.4}Zr{sub 2}O{sub 7} (Ln = La{sup 3+}, Nd{sup 3+}, Sm{sup 3+}, Dy{sup 3+} and Er{sup 3+}) ceramics synthesized at room temperature, by mechanically milling stoichiometric mixtures of high purity oxides. Regardless of chemical composition, powders milled for 27 h show XRD patterns similar to fluorite-type materials. Post-milling thermal treatments at 1500 °C, facilitates the evolution to the ordered pyrochlore derivative for Gd{sub 2}Zr{sub 2}O{sub 7}, and the La{sup 3+}-, Nd{sup 3+}-, and Sm{sup 3+}-containing materials. By contrast, samples containing the smaller lanthanides (Dy{sup 3+} or Er{sup 3+}), maintain the fluorite structure. Thermal conductivity of the as-prepared samples was obtained as a function of temperature, from thermal diffusivity, heat capacity and density values, using sintered pellets. We found that doping has an important effect in lowering Gd{sub 2}Zr{sub 2}O{sub 7} thermal conductivity, with final values ranging from 1.22 to 1.94 W m{sup −1} K{sup −1}; Nd{sup 3+}- and Er{sup 3+}-containing samples represent an optimum combination of defects and disordering of oxygen vacancies that generate the lowest conductivity values of all samples tested. - Highlights: • Gd{sub 2}Zr{sub 2}O{sub 7} doped with different lanthanides was synthesized by mechanical milling. • Smaller Ln{sup 3+} yield fluorites whereas larger lanthanides produce pyrochlores. • Thermophysical properties of the samples were measured as a function of temperature. • All samples show low thermal conductivities, and might find application as TBCs. • Doping is a valid strategy to increase Gd{sub 2}Zr{sub 2}O{sub 7} thermal resistance.

  15. Effect of yttrium and praseodymium on properties of Ce{sub 0.75}Zr{sub 0.25}O{sub 2} solid solution for CH{sub 4}-CO{sub 2} reforming

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qunying; Chen, Jixiang; Zhang, Jiyan [Department of Catalysis Science and Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2008-11-15

    Ce{sub 0.75}Zr{sub 0.25}O{sub 2} solid solutions doped with Y{sup 3+} or Pr{sup 4+}/Pr{sup 3+} were prepared by the co-precipitation method, and their physicochemical properties were characterized by means of N{sub 2} adsorption, X-ray diffraction, X-ray photoelectron spectroscopy, FT-Raman, and H{sub 2} temperature-programmed reduction and thermogravimetric analysis. Their performance in CH{sub 4}-CO{sub 2} reforming was also tested in an atmospheric fixed-bed reactor. Ce{sub 0.75}Zr{sub 0.25}O{sub 2} and Y{sup 3+} or Pr{sup 4+}/Pr{sup 3+} doped Ce{sub 0.75}Zr{sub 0.25}O{sub 2} solid solutions are of CaF{sub 2} structure, and the thermal stability of Ce{sub 0.75}Zr{sub 0.25}O{sub 2} is enhanced by doping Y{sup 3+} or Pr{sup 4+}/Pr{sup 3+}. Comparing with Ce{sub 0.75}Zr{sub 0.25}O{sub 2}, the migration of bulk lattice oxygen species become easier and the content of surface oxygen species is higher in the doped Ce{sub 0.75}Zr{sub 0.25}O{sub 2}, which is due to either oxygen vacancies or/and structural distortion resulted from the doping. The activity of the solid solutions in CH{sub 4}-CO{sub 2} reforming is closely related to the surface oxygen species. Y{sup 3+} or Pr{sup 4+}/Pr{sup 3+} doped Ce{sub 0.75}Zr{sub 0.25}O{sub 2}, especially the former, show higher activity than Ce{sub 0.75}Zr{sub 0.25}O{sub 2}, and Y{sup 3+} doped Ce{sub 0.75}Zr{sub 0.25}O{sub 2} possesses better stability. All of the catalysts have good coke resistance. The catalyst deactivation is mainly due to the catalyst sintering. (author)

  16. 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.)

  17. Nanoscopic characterization of Pr{sub 2}Zr{sub 2}O{sub 7} at Zr sites

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, J.A.; Caracoche, M.C.; Rodriguez, A.M. [Departamento de Fisica, IFLP, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Rivas, P.C. [Departamento de Fisica, IFLP, Facultad de Ciencias Exactas y Facultad de Ciencias Agronomicas y Forestales, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Bondioli, F.; Manfredini, T. [Dipartimento di Ingegneria dei Materiali e dell' Ambiente, Facolta di Ingegneria, Universita di Modena e Reggio Emilia, 41100 Modena (Italy); Ferrari, A.M. [Dipartimento di Scienze e Metodi dell' Ingegneria, Facolta di Ingegneria, Universita di Modena e Reggio Emilia, 42100 Reggio Emilia (Italy)

    2005-07-01

    By using Perturbed Angular Correlation Spectroscopy, a suitable technique to explore internal fields at nanoscopic scale, the electric field gradients at Zr{sup 4+} sites in the Pr{sub 2}Zr{sub 2}O{sub 7} compound have been determined as a function of temperature. Three nonequivalent nanoconfigurations are present, which have been interpreted with the aid of point charge model calculations. Two of them correspond to pyrochlore - oxygen defective and perfect structures -, and the third one to the pyrochlore-related defect fluorite structure. The most abundant interaction is a disordered and fluctuating electric field gradient, which describes the oxygen defective pyrochlore. As temperature increases, its gradual and reversible transformation towards the perfect form is observed. Below 750 C the oxygen vacancies movement, which exhibits an activation energy of 0.14 eV, is assumed to be due to vacancies jumping among 48f equivalent sites. At higher temperatures the movement is interpreted as the fast diffusion of oxygen vacancies involving 48f and 8b sites, thus giving place to anionic disorder. The activation energy for this movement has been determined to be of 0.85 eV. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. The Effects of Externally Solidified Product on Wave Celerity and Quality of Die Cast Products

    Energy Technology Data Exchange (ETDEWEB)

    Carroll Mobley; Yogeshwar Sahai; Jerry Brevick

    2003-10-10

    The cold chamber die casting process is used to produce essentially all the die cast aluminum products and about 50% of the die cast magnesium products made today. Modeling of the cold chamber die casting process and metallographic observations of cold chamber die cast products indicate that typically 5 to 20% of the shot weight is solidified in the shot sleeve before or during cavity filling. The protion of the resulting die casting which is solidified in the shot sleeve is referred to as externally solidified product, or, when identified as a casting defect, as cold flakes. This project was directed to extending the understanding of the effects of externally solidified product on the cold chamber die casting process and products to enable the production of defect-free die castings and reduce the energy associated with these products. The projected energy savings from controlling the fraction of externally solidified product in die cast components is 40 x 10 Btu through the year 2025.

  19. An Experimental Study on Solidifying Municipal Sewage Sludge through Skeleton Building Using Cement and Coal Gangue

    Directory of Open Access Journals (Sweden)

    Jiankang Yang

    2017-01-01

    Full Text Available The municipal sewage sludge typically has very high water content and low shear strength. Conventional methods of lime and cement solidification of municipal sewage sludge often suffer high cost, significant drying shrinkage, frequent cracking, high hydraulic conductivity, and low strength. To overcome these shortcomings, in this paper a skeleton-building method was used to solidify municipal sewage sludge in which coal gangue, cement and clay, and fiber were used as skeleton materials, cementation materials, and filling materials, respectively. Comprehensive laboratory tests including cracking, nitrogen adsorption, triaxial shearing, and permeability tests were performed to determine cracking, pore structure, shear strength, and hydraulic conductivity of municipal sewage sludge solidified with different proportions of coal gangue, cement, fiber, and clay. Based upon the experimental results, the mechanisms of the skeleton building using cement and coal gangue were discussed and factors controlling the mechanical and hydraulic behavior of the solidified soils were analyzed at both microscopic and macroscopic levels. Based upon the test results and analyses, recommendations were made for solidifying municipal sewage sludge through skeleton building using cement and coal gangue. The solidified soils have high soil strength, high resistance to cracking, and low hydraulic conductivity which are sufficient for being used as landfill liner.

  20. 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.

  1. Leaching of heavy metals from solidified waste using Portland cement and zeolite as a binder.

    Science.gov (United States)

    Napia, Chuwit; Sinsiri, Theerawat; Jaturapitakkul, Chai; Chindaprasirt, Prinya

    2012-07-01

    This study investigated the properties of solidified waste using ordinary Portland cement (OPC) containing synthesized zeolite (SZ) and natural zeolite (NZ) as a binder. Natural and synthesized zeolites were used to partially replace the OPC at rates of 0%, 20%, and 40% by weight of the binder. Plating sludge was used as contaminated waste to replace the binder at rates of 40%, 50% and 60% by weight. A water to binder (w/b) ratio of 0.40 was used for all of the mixtures. The setting time and compressive strength of the solidified waste were investigated, while the leachability of the heavy metals was determined by TCLP. Additionally, XRD, XRF, and SEM were performed to investigate the fracture surface, while the pore size distribution was analyzed with MIP. The results indicated that the setting time of the binders marginally increased as the amount of SZ and NZ increased in the mix. The compressive strengths of the pastes containing 20 and 40wt.% of NZ were higher than those containing SZ. The compressive strengths at 28 days of the SZ solidified waste mixes were 1.2-31.1MPa and those of NZ solidified waste mixes were 26.0-62.4MPa as compared to 72.9MPa of the control mix at the same age. The quality of the solidified waste containing zeolites was better than that with OPC alone in terms of the effectiveness in reducing the leachability. The concentrations of heavy metals in the leachates were within the limits specified by the US EPA. SEM and MIP revealed that the replacement of Portland cement by zeolites increased the total porosity but decreased the average pore size and resulted in the better containment of heavy ions from the solidified waste. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Estimation of Steel Solidified Layer Thickness, for Continuous Casting Control Purposes

    Directory of Open Access Journals (Sweden)

    Mihai MUNTEANU

    2008-08-01

    Full Text Available An important goal in continuous casting automation process rest in establishing a proper casting speed being able to assure a compromise between machine productivity and solidified skin cracking protection on the mould level. Contextually, this paper presents new solutions regarding solidified layer thickness estimation for steel continuous casting. The new model starts from actual stadium analysis and propose a solution for analytical model modification, in such a way that the model to approximate solidification dynamics at different casting speeds, using both important parameters for continuous casting process, meaning casting speed and time. A series of results obtained using numeric simulation are presented as a validation for proposed solution.

  3. 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.

  4. 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.

  5. Direct Numerical Study of a Molten Metal Drop Solidifying on a Cold Plate with Different Wettability

    Directory of Open Access Journals (Sweden)

    Truong V. Vu

    2018-01-01

    Full Text Available This paper presents a direct numerical simulation of solidification of a molten metal drop on a cold plate with various wettability by an axisymmetric front-tracking method. Because of the plate kept at a temperature below the fusion value of the melt, a thin solid layer forms at the plate and evolves upwards. The numerical results show that the solidifying front is almost flat except near the triple point with a high solidification rate at the beginning and final stages of solidification. Two solid-to-liquid density ratios ρsl = 0.9 (volume change and 1.0 (no change in volume, with two growth angles φ0 = 0° and 12° are considered. The presence of volume change and a non-zero growth angle results in a solidified drop with a conical shape at the top. The focusing issue is the effects of the wettability of the plate in terms of the contact angle φ0. Increasing the contact angle in the range of 45° to 120° increases time for completing solidification, i.e., solidification time. However, it has a minor effect on the conical angle at the top of the solidified drop and the difference between the initial liquid and final solidified heights of the drop. The effects of the density ratio and growth angle are also presented.

  6. Periodontal tissue regeneration using enzymatically solidified chitosan hydrogels with or without cell loading

    NARCIS (Netherlands)

    Yan, X.Z.; Beucken, J.J.J.P van den; Cai, X; Yu, N.; Jansen, J.A.; Yang, F.

    2015-01-01

    This study is aimed to evaluate the in vivo biocompatibility and periodontal regenerative potential of enzymatically solidified chitosan hydrogels with or without incorporated periodontal ligament cells (PDLCs). To this end, chitosan hydrogels, with (n=8; CHIT+CELL) or without (n=8; CHIT)

  7. Effect of ball-milling and shot-peening on Zr{sub 55}Al{sub 10}Ni{sub 5}Cu{sub 30} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Tokujiro [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)]. E-mail: toku@imr.tohoku.ac.jp; Takahashi, Tsuyoshi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kimura, Hisamichi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Inoue, Akihisa [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2007-03-14

    Effect of ball-milling and shot-peening on a metallic glass Zr{sub 55}Al{sub 10}Ni{sub 5}Cu{sub 30}, which possesses a large supercooled liquid region, has been investigated by means of differential scanning calorimetry, x-ray diffractometry and transmission electron microscopy. Metallic glassy ribbons, powders and plates were prepared by melt-spinning, gas-atomizing and mold-clamp casting techniques, respectively. No structural changes were observed in both the ribbon and powder specimens by ball-milling for around 100 h; however, the powder specimens were crystallized by Fe contamination when they were ball-milled for 540 h. No structural evolution was also observed when the plate specimens were subjected to shot-peening, while crystallized plate specimens were easily amorphized by mild and short period shot-peening. These results imply high phase stability of the Zr{sub 55}Al{sub 10}Ni{sub 5}Cu{sub 30} metallic glass against deformation.

  8. 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)}.

  9. 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.

  10. Optical and EPR studies of Gd{sub 2}Zr{sub 2}O{sub 7} phosphors prepared via solution combustion method

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vijay, E-mail: vijayjiin2006@yahoo.com [Department of Chemical Engineering, Konkuk University, Seoul 143-701 (Korea, Republic of); Sivaramaiah, Gobburu [Department of Physics, Government College (M), Kadapa 516004 (India); Rao, J.L. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Hwan Kim, Sang, E-mail: sanghhkim@konkuk.ac.kr [Department of Chemical Engineering, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2013-05-01

    Phosphor powder of Gd{sub 2}Zr{sub 2}O{sub 7} has been prepared by the urea combustion route. Phase evolution of the synthesized powder is determined by X-ray diffraction (XRD) technique. The structural environment between the Gd{sup 3+} and the zirconium oxide lattice has been investigated using electron paramagnetic resonance (EPR), diffuse reflectance and photoluminescence (PL) studies. The EPR spectrum of Gd{sub 2}Zr{sub 2}O{sub 7} phosphor exhibits a broad and intense signal at g≈2.0 and this has been attributed to Gd{sup 3+} ions in octahedral symmetry with strong dipolar interactions between Gd{sup 3+} ions. The intensity of the spectrum increases with temperature lowering from 296 to 110 K following the usual Boltzmann law. The g value is invariant with temperature variation. The diffuse reflectance spectrum exhibits two sharp and weak bands characteristic of Gd{sup 3+} ions in octahedral symmetry. The photoluminescence spectrum exhibits several bands characteristic of Gd{sup 3+} ions in octahedral symmetry.

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. A review of rapid solidification studies of intermetallic compounds

    Science.gov (United States)

    Koch, C. C.

    1985-01-01

    A review of rapid solidification studies of high-temperature ordered intermetallic compounds is presented. Emphasis is on the nickel - and iron- aluminides which are of potential interest as structural materials. The nickel-base aluminides which have been rapidly solidified exhibit changes in grain size, compositional segregation, and degree of long range order (as reflected in APB size and distribution) which markedly affect mechanical properties. Some experiments indicate the formation of a metastable L1(2) phase in rapidly solidified Fe-(Ni,Mn)-Al-C alloys, while other work observes only a metastable fcc phase in the same composition range. The metastable phases and/or microstructures in both nickel and iron aluminides are destroyed by annealing at temperatures above 750 K, with subsequent degradation of mechanical properties. Rapid solidification studies of several other intermetallic compounds are briefly noted.

  16. Effect of heat treatment on the fracture behaviour of directionally solidified (gamma/gamma-prime)-alpha alloy

    Science.gov (United States)

    Sriramamurthy, A. M.; Tewari, S. N.

    1987-01-01

    An investigation is conducted into the influence of various heat treatments on the work of fracture and its relation to microstructure for a directionally solidified Ni-33Mo-5.7Al (wt pct) (gamma/gamma-prime)-alpha alloy. The jagged crack propagation observed is due to delamination of the ligaments and associated plastic deformation. Fracture behavior is examined with respect to alloy microstructures and load-deflection curves. The four heat-treatment conditions considered are: (1) as-directionally solidified, (2) solutionized, (3) directionally solidified and thermally cycled, and (4) solutionized and thermally cycled.

  17. Structural and magnetic characterization of Zr-substituted magnetite (Zr{sub x}Fe{sub 3−x}O{sub 4}, 0≤x≤1)

    Energy Technology Data Exchange (ETDEWEB)

    Gangwar, A.; Alla, S.K.; Srivastava, M. [Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Meena, S.S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Prasadrao, E.V. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Mumbai (India); Mandal, R.K. [Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Yusuf, S.M. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Prasad, N.K., E-mail: nandkp.met@iitbhu.ac.in [Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2016-03-01

    We report the preparation of monophasic Zr-substituted magnetite (Zr{sub x}Fe{sub 3−x}O{sub 4}; 0≤x≤1) nanoparticles by wet chemical route. Such a report is lacking in the literature. Rietveld refinement of the X-ray diffraction (XRD) data suggests continuous decrease in the lattice parameter with increased Zr-substitutions. From TEM analysis, the size of the as synthesized particles was found to be in the range of 5–20 nm. The differential scanning calorimetry (DSC) curves for the samples with different amount of substitutions displayed considerable differences in their behaviors. The room temperature specific magnetization at 2 T has been found to decrease from 50 (x=0.2) to 41 A m{sup 2}/kg (x=1.0) with increased Zr-substitution. From XRD and magnetic behavior analysis we could suggest that due to occupation of Zr{sup 4+} ions at tetrahedral and octahedral voids of Fe{sub 3}O{sub 4}, the amount of Fe{sup 2+} was more at octahedral site for x≤ 0.4 and at tetrahedral site for x>0.4 respectively. The ferrofluids prepared from these magnetic nanoparticles possessed good heating ability and Specific Absorption Rate (SAR) values suitable for bioapplications. - Highlights: • We could synthesize nanoparticles of monophasic Zr{sub x}Fe{sub 3−x}O{sub 4} up to x=1. • The ionic distribution was found to be like: for x≤0.4: (Fe{sup 3+}{sub 1−x}Fe{sup 2+}{sub x/2−y}Zr{sup 4+}{sub x/2+y}){sub A}[Fe{sup 3+}{sub 1−x}Fe{sup 2+}{sub 1+x/2+y}Zr{sup 4+}{sub x/2−y}]{sub B}O{sub 4} and for x>0.4: (Fe{sup 3+}{sub 1−x}Fe{sup 2+}{sub x/2+y}Zr{sup 4+}{sub x/2−y}){sub A}[Fe{sup 3+}{sub 1−x}Fe{sup 2+}{sub 1+x/2−y}Zr{sup 4+}{sub x/2+y}]{sub B}O{sub 4}. • Significantly high M{sub S} value (=41 A m{sup 2}/kg) at 2 T even for higher substitutions (x=1). • Considerable difference in the magnetic behavior of Zr{sub x}Fe{sub 3−x}O{sub 4} and Ti{sub x}Fe{sub 3−x}O{sub 4}.

  18. The effect of gravity level on the average primary dendritic spacing of a directionally solidified superalloy

    Science.gov (United States)

    Mccay, M. H.; Lee, J. E.; Curreri, P. A.

    1986-01-01

    The effect of alternating low (0.01 g) and high (1.8 g) gravity force on the primary spacings in the dendrite structure in a directionally solidified Ni-based superalloy (PWA 1480, containing 5 pct Co, 10 pct Cr, 4 pct W, 12 pct Ta, 5 pct Al, 1.5 pct Ti, and the balance Ni) was investigated using samples solidified in a directional solidification furnace aboard the NASA KC-135 aircraft that made a series of low-g parabolas. The cross-section slices for each growth rate were polished and etched with Kallings II, and the primary dendritic arm spacings were measured using the method of Jacobi and Schwerdtfeger (1976). The arm spacings were found to fluctuate with gravity force, increasing as the gravity level decreased, and growing finer as gravity increased.

  19. 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.

  20. Characterization of solidified gas thin film targets via alpha particle energy loss

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, M.C. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Phys. and Astron.; Beer, G.A.; Douglas, J.L.; Knowles, P.E.; Maier, M.; Mason, G.R.; Porcelli, T.A. [Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8W 2Y2 (Canada); Beveridge, J.L.; Marshall, G.M.; Mulhauser, F.; Olin, A. [TRIUMF, Vancouver, BC, V6T 2A3 (Canada); Huber, T.M. [Department of Physics, Gustavus Adolphus College, St.Peter, MN 56082 (United States); Jacot-Guillarmod, R. [Physics Institute, Universite de Fribourg, CH-1700 Fribourg (Switzerland); Kim, S.K. [Department of Physics, Jeonbuk National University, Jeonju City 560-756 (Korea, Republic of); Kunselman, A.R. [Department of Physics, University of Wyoming, Laramie, WY 82071 (United States); Petitjean, C. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Zmeskal, J. [Austrian Academy of Sciences, A-1090 Wien (Austria); TRIUMF Collaboration

    1997-08-11

    A method is reported for measuring the thickness and uniformity of thin films of solidified gas targets. The energy of {alpha} particles traversing the film is measured and the energy loss is converted to thickness using the range. The uniformity is determined by measuring the thickness at different positions with an array of sources. Monte Carlo simulations have been performed to study the film deposition mechanism. Thickness calibrations for a TRIUMF solid hydrogen target system are presented. (orig.).

  1. 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.

  2. 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.

  3. Investigation of the as-solidified microstructure of an Al–Mg–Si–Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kai; Song, Min [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Du, Yong, E-mail: yongducalphad@gmail.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Tang, Ying [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China); Dong, Hongbiao [Department of Engineering, University of Leicester, Leicester LE1 7RH (United Kingdom); Ni, Song [State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083 (China)

    2014-07-25

    Highlights: • AlMgSiCu-Q particles preferentially grow along the solidification direction. • A new orientation relationship between Q particles and α-Al matrix was found. • The solidified microstructure was simulated based on Scheil–Gulliver model. • The effect of solidification on solution and aging processes were analyzed. - Abstract: The as-solidified microstructure of an Al–Mg–Si–Cu alloy was characterized by scanning electron microscopy and transmission electron microscopy. Quaternary Q particles were found to elongate preferentially along the solidification direction of the cylindrical cast ingot, whilst a small number of Si leaf-like particles aggregate mainly along the grain boundaries. The volume fractions of the Q and Si particles are quantitatively measured from electron microscopy images and thermodynamically simulated based on the Scheil–Gulliver solidification model. The results from experimental measurement agree well with those from simulation. The Q particles, which have dendrite-like internal structure and are uniformly distributed within the α-Al grains with a different orientation from that found in the aged alloys, are fast-dissolving and aid the formation of uniform aged microstructures. The aggregation of the Si particles along the grain boundaries in the as-solidified microstructure results in Si-rich boundaries even after a solution treatment, and causes the re-emergence of Si particles in the over-aged microstructure. This phenomenon helps to reduce the width of the precipitate-free zones.

  4. Cryogenic treatment induced hardening of Cu{sub 45}Zr{sub 45}Ag{sub 7}Al{sub 3} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.K.; Chen, Z.H.; Chen, D., E-mail: ma97chen@hotmail.com; Zheng, Q.

    2014-01-15

    Little is known about the mechanical properties of bulk metallic glassy alloys (BMGs) after cryogenic treatment (CT). Cu{sub 45}Zr{sub 45}Ag{sub 7}Al{sub 3} BMGs were treated in cryogenic temperatures for four chosen holding times. Compared with the as-cast sample, the compressive fracture strength of this BMG increased with increasing CT time. Furthermore, the CT changes the fracture mode from the ductile to the brittle. And CT brought about the precipitation of the AlCu{sub 2}Zr and Cu{sub 5}Zr phases which were accompanying with the morphology modification and contributed to the mechanical properties improvement of this BMG.

  5. 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.

  6. 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.

  7. 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.

  8. Crystal-field study of magnetization and specific heat properties of frustrated pyrochlore Pr{sub 2}Zr{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Alam, J.; Jana, Y.M., E-mail: yatramohan@yahoo.com; Biswas, A. Ali

    2016-10-15

    The experimental results of temperature dependent dc magnetic susceptibility, field dependent isothermal magnetization, magnetic specific heat and entropy of the pyrochlore Pr{sub 2}Zr{sub 2}O{sub 7} are simulated and analyzed using appropriate D{sub 3d} crystal-field (CF) and anisotropic molecular field tensors at Pr-sites in the self-consistent mean-field approach involving four magnetically non-equivalent rare-earth spins on the tetrahedral unit of the pyrochlore structure. CF level pattern and wave-functions of the ground {sup 3}H{sub 4} multiplet of the Pr{sup 3+} ions are obtained considering intermediate coupling between different Russell-Saunders terms of the 4f{sup 2} electronic configurations of Pr-ion and J-mixing effects. CF analysis shows that the CF ground-state of the Pr{sup 3+} ion in Pr{sub 2}Zr{sub 2}O{sub 7} is a well-isolated doublet, with significant admixtures of terms coming from |M{sub J}=±4〉 and |M{sub J}=±1〉, and the Pr-spins are effectively Ising-like along the local <111> axes. Magnetic specific heat in zero-field is simulated by considering a temperature dependence of the exchange splitting of the ground doublet. - Highlights: • Full CF diagonalization using intermediate coupling and J-mixing. • Pr-spins are Ising-like along local [111] axis. • Magnetic specific heat is due to temperature dependence exchange splitting of ground CF doublet.

  9. Microwave-induced synthesis of pyrophosphate Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} and TiP{sub 2}O{sub 7} with enhanced sorption capacity for uranium (VI)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); School of Chemistry and Materials Science, Liaoning Shihua University, Fushun 113001 (China); Ye, Junwei, E-mail: junweiye@dlut.edu.cn [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Rauf, Abdul [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Wu, Xiaomeng; Liu, Hongxue [School of Chemistry and Materials Science, Liaoning Shihua University, Fushun 113001 (China); Ning, Guiling, E-mail: ninggl@dlut.edu.cn [State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Jiang, Heng, E-mail: hjiang78@hotmail.com [School of Chemistry and Materials Science, Liaoning Shihua University, Fushun 113001 (China)

    2016-09-05

    Highlights: • New zirconium titanium pyrophosphates Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} were synthesized. • A facile microwave induced route was employed. • The adsorption capacity of Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} for U(VI) was adjusted by Ti content. • The maximum amount of TiP{sub 2}O{sub 7} for U(VI) reached up to 309.8 mg g{sup −1}. • Adsorption kinetics and thermodynamic analysis of Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} were performed. - Abstract: A series of nanostructured pyrophosphates Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0), have been prepared via a facile microwave induced route in which zirconium hydroxide, titanium hydroxide and phosphoric acid were used as Zr, Ti and P sources, respectively. It is demonstrated the isomorphous substitution of Zr{sup 4+} by Ti{sup 4+} results in a decrease of the size and an enhancement of the adsorption capacity of the obtained particles for U(VI) in aqueous solution. The maximum amount of TiP{sub 2}O{sub 7} for U(VI) reached up to 309.8 mg g{sup −1} under the experimental conditions (pH = 5, t = 60 min and T = 303 K). The as-obtained specific metal pyrophosphates exhibit a considerably higher adsorption capability for U(VI) in aqueous solution compared with Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} prepared by calcined method, showing a high potential for U(VI) sequestration applications. The adsorption kinetics and thermodynamic analysis of Zr{sub 1-x}Ti{sub x}P{sub 2}O{sub 7} on adsorption of U (VI) were performed, and a possible adsoprtion mechanism was also proposed.

  10. Modeling second-phase formation during rapid resolidification of stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, J.W. (Lawrence Livermore National Lab., CA (USA)); Eagar, T.W.; Allen, S.M. (Massachusetts Inst. of Tech., Cambridge, MA (USA))

    1991-01-28

    Many common stainless steel (SS) alloy microstructures consist of a mixture of ferrite and austenite phases, however, when these alloys are rapidly resolidified using laser beam (LB) or electron beam (EB) processes they solidify in the single-phase-austenite or single-phase-ferrite mode. This paper investigates the influence of solidification rate on the reduction, and eventual elimination, of second phases during the rapid solidification of SS alloys. The influence of solidification rate on the ferrite content of these alloys was studied by calculating the dendrite-tip undercooling and then incorporating these results into a solute-redistribution model to calculate the relative fractions of primary and secondary phase that solidify from the melt. Single-phase solidification was predicted at high cooling rates and was confirmed through STEM analysis, showing solidification microstructures void of any significant microchemical composition gradients. Results showed a rapid-solidification model was used to calculate the relative fractions of primary and secondary phases that form during the resolidification of stainless steel alloys. The rapid-solidification model shows that the ferrite content of primary-austenite solidified alloys decreases and the ferrite content of primary-ferrite solidified alloys increases with increasing cooling rate. Results of the model indicate that primary-austenite alloys will solidify in the single-phase mode at all interface velocities greater than about 20 mm/s. This value correlates well with experiments. Results of the model indicate that primary-ferrite alloys will solidify in the single-phase mode at all interface velocities greater than about 50 mm/s. The experimentally-observed interface velocity for single-phase-ferrite solidification is significantly less (10 mm/s). This discrepancy is proposed to be related to the relative difficulty of nucleating austenite from the eutectic liquid. 13 refs., 5 figs., 2 tabs.

  11. Neutron diffraction studies of Zr-containing intermetallic hydrides with ordered hydrogen sublattice. V. Orthorhombic Zr{sub 3}CoD{sub 6.9} with filled Re{sub 3}B-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Riabov, A.B.; Yartys, V.A. [Nat. Acad. of Sci., Lviv (Ukraine). Metal Hydrides Dept.; Fjellvaag, H.; Hauback, B.C.; Soerby, M.H. [Institute for Energy Technology, P.O. Box 40, Kjeller (Norway)

    2000-01-10

    For pt.IV see ibid., vol.290, p.157-163, 1999. Zr{sub 3}CoD{sub 6.9} deuteride (space group Cmcm; a=3.5959(1); b=10.9734(3); c=9.5961(3) A) has been studied by high resolution powder X-ray and neutron diffraction. Rietveld profile refinements showed that it is isostructural to Zr{sub 3}FeD{sub 6.7} with a filled Re{sub 3}B-type structure. D atoms occupy four types of interstitial positions. Deuterium sublattice is completely ordered and can be described as a spatial stacking of deformed cubes ZrD{sub 8} and deformed cubes with an extra ninth vertex ZrD{sub 9}. The shortest interatomic distances are: Zr-D=2.044(5); Co-D=1.727(8); D-D=2.025(6) A. (orig.)

  12. 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.

  13. 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.

  14. Non-isothermal crystallization kinetics and fragility of (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} bulk metallic glass investigated by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Man, E-mail: zhuman0428@126.com [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an, Shaanxi 710032 (China); Li, Junjie [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Yao, Lijuan; Jian, Zengyun; Chang, Fang’e [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an, Shaanxi 710032 (China); Yang, Gencang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

    2013-08-10

    Highlights: • Non-isothermal crystallization kinetics of (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} BMGs was studied. • Two-stage of crystallization process is confirmed by DSC. • The nucleation process is difficult than growth process during crystallization. • The second crystallization process is the most sensitive to heating rate. • Kinetic fragility index is evaluated suggesting it is an intermediate glass. - Abstract: In this paper, bulk metallic glasses with the composition of (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} were prepared by copper mold casting technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate its structure and non-isothermal crystallization kinetics. DSC traces revealed that it undergoes two-stage crystallization. The activation energies corresponding to the characteristic temperatures have been calculated, and the results reveal that the as-cast alloys have a good thermal stability in thermodynamics. Based on Kissinger equation, the activation energies for glass transition, the first and second crystallization processes were obtained as 485 ± 16 kJ/mol, 331 ± 7 kJ/mol and 210 ± 3 kJ/mol, respectively, suggesting that the nucleation process is more difficult than the grain growth process. The fitting curves using Lasocka's empirical relation show that the influence of the heating rate for crystallization is larger than glass transition. Furthermore, the kinetic fragility for (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} bulk metallic glasses is evaluated. Depending on the fragility index, (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} bulk metallic glasses should be considered as “intermediate glasses”.

  15. 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)

  16. Structural, electrical and electrochemical properties of Li{sub 4}Zr{sub x}Si{sub 1-x}O{sub 4} (0.02 ≤ x ≤ 0.06) ceramic electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Adnan, S. B. R. S.; Mohamed, N. S. [Centre for Foundation Studies in Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-08-28

    The aim of this work was to investigate the structural, electrical and electrochemical properties of Li{sub 4}Zr{sub x}Si{sub 1-x}O{sub 4} (0.02 ≤ x ≤ 0.06) compounds prepared via sol gel method. The X-ray Diffraction results showed that all compounds can be indexed to monoclinic structure in space group P2{sub 1/m}. The Li{sub 4}Zr{sub 0.06}Si{sub 0.94}O{sub 4} compound showed highest bulk, grain boundary and total conductivity values of 1.19 × 10{sup −4} S cm{sup −1}, 4.75 × 10{sup −5} S cm{sup −1} and 3.41 × 10{sup −5} S cm{sup −1} respectively. The insertion of Zr{sup 4+} is found to enhance conductivity of the parent sample Li{sub 4}SiO{sub 4}. Linear sweep voltammetry results showed that Li{sub 4}Zr{sub 0.06}Si{sub 0.94}O{sub 4} ceramic electrolytes was electrochemically stable up to 5.07 V versus a Li{sup +}/Li{sup +} reference electrode.

  17. Non-isothermal crystallization kinetics and glass-forming ability of Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} bulk metallic glass investigated by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Pan; Zhao, Shaofan; Yao, Kefu [Tsinghua University, School of Materials Science and Engineering, Beijing (China); Wang, Xin [Hebei University of Technology, School of Materials Science and Engineering, Tianjin (China)

    2015-07-15

    The non-isothermal crystallization kinetics and glass-forming ability of Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} glassy alloy were investigated by differential scanning calorimetry. The activation energies corresponding to the characteristic temperatures have been calculated by Kissinger and Ozawa equations. Based on Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall models, it has been found that the local activation energy is higher at the beginning of the crystallization process for the first exothermic peak. The local Avrami exponent indicates that the first-step crystallization is mainly a high-dimensional nucleation and growth with an increasing nucleation rate. According to the calculated fragility index, Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} alloy can be classified as ''strong glass former.'' The studied alloy also possesses a critical size up to centimeter order, and the high glass-forming ability is probably related to the relatively low Gibbs energy difference between the liquid and crystalline states. The critical cooling rate of Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} glassy alloy has also been determined using Barandiaran-Colmenero's method. (orig.)

  18. 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.

  19. 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...... formulation revealed 9.63-fold and 8.44-fold higher Caco-2 uptake of tamoxifen and quercetin, respectively in comparison with free drug counterparts. CONCLUSIONS: The developed formulation strategy revealed a great potential for oral delivery of combination drugs having utmost clinical relevance....

  20. Pressure transmitting medium Daphne 7474 solidifying at 3.7 GPa at room temperature

    Science.gov (United States)

    Murata, Keizo; Yokogawa, Keiichi; Yoshino, Harukazu; Klotz, Stefan; Munsch, Pascal; Irizawa, Akinori; Nishiyama, Mototsugu; Iizuka, Kenzo; Nanba, Takao; Okada, Tahei; Shiraga, Yoshitaka; Aoyama, Shoji

    2008-08-01

    A pressure transmitting medium named Daphne 7474, which solidifies at Ps=3.7 GPa at room temperature, is presented. The value of Ps increases almost linearly with temperature up to 6.7 GPa at 100 °C. The high pressure realized by a medium at the liquid state allows a higher limit of pressurization, which assures an ideal hydrostatic pressure. We show a volume change against pressure, pressure reduction from room to liquid helium temperature in a clamped piston cylinder cell, pressure distribution and its standard deviation in a diamond anvil cell, and infrared properties, which might be useful for experimental applications.

  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. Leaching of rapidly quenched Al65Cu20Fe15 quasicrystalline ribbons

    Indian Academy of Sciences (India)

    2017-12-06

    Dec 6, 2017 ... The Al–Mn QC exhibiting a simple icosahedral (i) symmetry. (Pm35), however the ordered QC was showing face-centred icosahedral (FCI) symmetry (Fm35) reported in annealed. Al–Cu–Fe rapidly solidified alloy [7,8]. A stable (i) Al–Cu–. Fe ternary QC has been discovered, which is a part of the.

  3. 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

  4. AE Monitoring of Diamond Turned Rapidly Soldified Aluminium 443

    Science.gov (United States)

    Onwuka, G.; Abou-El-Hossein, K.; Mkoko, Z.

    2017-05-01

    The fast replacement of conventional aluminium with rapidly solidified aluminium alloys has become a noticeable trend in the current manufacturing industries involved in the production of optics and optical molding inserts. This is as a result of the improved performance and durability of rapidly solidified aluminium alloys when compared to conventional aluminium. Melt spinning process is vital for manufacturing rapidly solidified aluminium alloys like RSA 905, RSA 6061 and RSA 443 which are common in the industries today. RSA 443 is a newly developed alloy with few research findings and huge research potential. There is no available literature focused on monitoring the machining of RSA 443 alloys. In this research, Acoustic Emission sensing technique was applied to monitor the single point diamond turning of RSA 443 on an ultrahigh precision lathe machine. The machining process was carried out after careful selection of feed, speed and depths of cut. The monitoring process was achieved with a high sampling data acquisition system using different tools while concurrent measurement of the surface roughness and tool wear were initiated after covering a total feed distance of 13km. An increasing trend of raw AE spikes and peak to peak signal were observed with an increase in the surface roughness and tool wear values. Hence, acoustic emission sensing technique proves to be an effective monitoring method for the machining of RSA 443 alloy.

  5. 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.

  6. Extracellular micro and nanostructures forming the velvet worm solidified adhesive secretion

    Science.gov (United States)

    Corrales-Ureña, Yendry Regina; Sanchez, Angie; Pereira, Reinaldo; Rischka, Klaus; Kowalik, Thomas; Vega-Baudrit, José

    2017-12-01

    The onychophoran Epiperipatus hilkae secrets a sticky slime that solidifies almost immediately upon contact with air and under high humidy environmental condition forming a glassy like material. The general adhesive biochemical composition, the releasing and hardening mechanism have been partially described in literature. In this study, the structural characterization of the extracellular microstructures and nanostructures forming the solid adhesive of the secretion from Epiperipatus hilkae velvet worm is presented. The adhesive secretion is formed by macro-threads, which, in their solid state, are composed of globular particles approximately 700 nm in diameter that are distributed homogeneously throughout the matrix surface, and nanoparticles approximately 70 nm in diameter that and 6 nm in height self-assemble forming fiber-like structures. Nanoparticules with approximately 2 nm heights and others with non roundish forms are also observed. These 70 nm nano particles could be associated to proteins that form high density coverage films with low roughness; suggesting the formation of 2D ordered films. A crystalline and an amorphous phase composes the solidified secretion. The glassy or viscoelastic properties depend on the time in contact with air before being adhered to a solid surface and/or the mechanical stimulus; suggesting a key role of the drying on the hardening process.

  7. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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/sup 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.

  9. Effect of hafnium addition on solidifi cation structure of cast Ti-46Al alloys

    Directory of Open Access Journals (Sweden)

    Su Yanqing

    2008-11-01

    Full Text Available To investigate the effect of hafnium addition on the solidifi cation structure, Ti-46Al alloys with nominal compositions of Ti-46Al-xHf (x = 0, 3, 5, 7 (at.% were arc-melted into small ingots in an argon atmosphere. The characteristics of the macrostructures and microstructures were studied using a linear intercept method, OM, SEM (BSE, XRD and TEM. The results showed that the ingots with Hf have near lamellar microstructure in columnar and dendrite morphology. The hafnium concentration has a strong effect on the columnar spacing refi nement. Increasing Hf from 0 to 7 (at.%, the columnar spacing can be reduced from ~ 1000 to ~ 400 μm. Constitute phases of the ingots are α2, a small amount of B2 and c. Most of the B2 phases, richer in Hf and leaner in Al and Ti, exist on the node of the dendrite core in block shape and a little across the lamellar colonies in stick shape. The c phases exist on the boundaries of lamellar colonies in small cellular shape. There also exists a segregation of Hf on the columnar and dendrite core. Particularly, both the α- and β-phase form from the melt as prior phases. The possible phase sequencing during solidifi cation and solid-state transformations with Hf is given in this paper.

  10. 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.

  11. Relationship between cooling rate and microsegregation in bottom-chilled directionally solidified ductile irons

    Directory of Open Access Journals (Sweden)

    Chang W.S.

    2013-01-01

    Full Text Available This study explores the relationship between cooling rate and microsegregation of directionally solidified ductile iron. The unidirectional heat transfer system used in this research is made up of a copper mold kept chilled by circulating water and embedded in the bottom of Furan sand mold. Thermocouples are connected to the computer measuring system to record the cooling curves of the castings at a distance of 0, 30, 60 and 90 mm from the chilled copper mold surface. Alloys including Mn, Cr, Cu, Ni and Ti were added to the specimens. Electron microprobe analysis (EPMA was employed to examine distribution of elements between the dendrite arms and nodular graphite. Results show that unidirectional heat transfer affects directly the solidification mode and microstructure of the casting. The cooling curves reveal that local solidification time increases with increasing distance from the chilled copper mold surface. Different solidification rates with corresponding microstructure and element segregation were observed in the same unidirectionally solidified casting. Local solidification time was closely related to element segregation. The effective segregation coefficient (Keff calculated using the Scheil equation was found to vary, according to the stage of solidification. The actual segregation characteristics of complex alloys generally follow the Scheil equation.

  12. Shape Memory Characteristics of Rapidly Solidified Ti-37.8Cu-18.7Ni Alloy Ribbons

    Science.gov (United States)

    Ramos, Alana Pereira; de Castro, Walman Benicio

    Amorphization and martensitic transformation (Ms) characteristics of Ti-Ni-Cu alloy ribbons prepared by melt spinning were investigated by means of differential scanning calorimetry and X-ray diffraction. In these experiments particular attention has been paid to change the wheel linear velocity from 21 to 63 m/s. Then the cooling rates of ribbons were controlled. The effect of this cooling rate and alloy composition on martensitic transformation behavior is discussed.

  13. Evolution of the dendritic morphology with the solidification velocity in rapidly solidified Al-4.5wt.%Cu droplets

    Science.gov (United States)

    Bedel, M.; Reinhart, G.; Gandin, Ch-A.; Bogno, A.-A.; Nguyen-Thi, H.; Henein, H.

    2015-06-01

    The microstructure morphology of Al-4.5wt.%Cu droplets formed by the Impulse Atomization technique is investigated. Three-dimensional reconstructions by synchrotron X- ray micro-tomography of several droplets reveal different morphologies in droplets of similar diameter and produced in the same batch. Moreover, microstructural features also indicate that the development of the dendrite arms occurs in some droplets along crystallographic axes instead of the usual directions observed in conventional casting for the same alloy. It has been observed that such an unusual growth direction of the dendrites is directly related to the solidification velocity. We underpin these results by carrying out comparisons with a solidification model. Predictions are used to discuss the change of dendrite growth direction, as well as the existence of a dendrite growth direction range for a given type of droplets. In addition, the effect of the droplet size and the cooling gas on the dendrite growth direction range observed experimentally is also investigated by using the model.

  14. Effect of Annealing on the Microstructure of Rapidly Solidified Foils of Alloy Bi50Sn35In15

    Science.gov (United States)

    Shepelevich, V. G.; Shcherbachenko, L. P.

    2016-07-01

    The effect of annealing on the microstructure of foils of alloy Bi50Sn35In15 is studied. It is shown that prolongation of the annealing time is accompanied by coarsening of the structure, which reduces the specific surface of the interfaces virtually without changing the volume fractions of the phases.

  15. Microstructure and Phase Formation in a Rapidly Solidified Laser-Deposited Ni-Cr-B-Si-C Hardfacing Alloy

    NARCIS (Netherlands)

    Hemmati, Ismail; Ocelik, Vaclav; Csach, Kornel; de Hosson, Jeff Th M.

    In this study, microstructural evolutions and phase selection phenomena during laser deposition of a hardfacing Ni-Cr-B-Si-C alloy at different processing conditions are experimentally investigated. The results show that even minor variations in the thermal conditions during solidification can

  16. THE EFFECT OF PREPARATION CONDITIONS OF RAPIDLY SOLIDIFIED IRON BASED GRANULES ON PROPERTIES OF COMPOSITE MATERIAL FORMED BY CASTING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    A. S. Kalinichenko

    2017-01-01

    Full Text Available The variety of requirements for friction pairs requires the development of different technologies for the production of tribological materials with reference to the operation modes. Composite materials obtained by the casting technology have been successfully applied for the normalization of the thermomechanical state of the steam turbines. These composites consist of the matrix based on copper alloys reinforced with cast iron granules. Because the structure and properties of cast iron are determined by the conditions of their production studies have been conducted on determination of preparation conditions on grain structure and properties of the synthesized composite material. Using an upgraded unit for production of granules technological regimes were determined providing narrow fractional composition. It has been found that granules formed are characterized with typical microstructure of white cast iron containing perlite and ledeburite. Microhardness of pilot cast iron granules is characterized by high values (from 7450 up to 9450 MPa and depends on the size of the fraction. Composite materials obtained using experimental granules had a microhardness of the reinforcing cast iron granules about 3500 MPa, and a bronze matrix – 1220 MPa, which is higher than the hardness of the composite material obtained by using the annealed DCL-1granules (2250 MPa. Metal base of experimental granules in the composite material has the structure of perlitic ductile iron with inclusions of ferrite not exceeding 10–15% and set around a flocculent graphite. As a result, the increase of physical-mechanical properties of finished products made of composite material is observed. 

  17. Homogenization and texture development in rapidly solidified AZ91E consolidated by Shear Assisted Processing and Extrusion (ShAPE)

    Energy Technology Data Exchange (ETDEWEB)

    Overman, N. R.; Whalen, S. A.; Bowden, M. E.; Olszta, M. J.; Kruska, K.; Clark, T.; Stevens, E. L.; Darsell, J. T.; Joshi, V. V.; Jiang, X.; Mattlin, K. F.; Mathaudhu, S. N.

    2017-07-01

    Shear Assisted Processing and Extrusion (ShAPE) -a novel processing route that combines high shear and extrusion conditions- was evaluated as a processing method to densify melt spun magnesium alloy (AZ91E) flake materials. This study illustrates the microstructural regimes and transitions in crystallographic texture that occur as a result of applying simultaneous linear and rotational shear during extrusion. Characterization of the flake precursor and extruded tube was performed using scanning and transmission electron microscopy, x-ray diffraction and microindentation techniques. Results show a unique transition in the orientation of basal texture development. Despite the high temperatures involved during processing, uniform grain refinement and material homogenization are observed. These results forecast the ability to implement the ShAPE processing approach for a broader range of materials with novel microstructures and high performance.

  18. Effect of Ce on Casting Structure of Near-rapidly Solidified Al-Zn-Mg-Cu Alloy

    Directory of Open Access Journals (Sweden)

    HUANG Gao-ren

    2017-11-01

    Full Text Available Through using XRD,DSC,SEM,EDS and other modern analysis methods, the effects of rare earth element Ce on microstructure and solidification temperature of Al-Zn-Mg-Cu under different cooling rates were studied, the principle of Ce on grain refining and melt cleaning of alloys was analyzed and discussed. The results show that MgZn2 phase and α-Al matrix are the main precipitations, Al,Cu,Mg and other elements dissolve in MgZn2 phase, a new phase Mg(Zn, Cu, Al2 is formed, solute elements in the grain boundary have higher concentration, eutectic reaction takes place between MgZn2 and α-Al, lamellar eutectic structure is generated. The addition of Ce decreases the dendritic arm spacing,reduces the layer spacing between eutectic phases and refines the eutectic structure and the grain significantly, and inhibits the appearance of the impurity phase Al7Cu2Fe in aluminum alloys. The addition of Ce also reduces the precipitation temperature of α-Al matrix and eutectic phase by 6.4℃ and 5.6℃ respectively.

  19. 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)

  20. 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.

  1. Parametric Study to Determine the Effect of Temperature on Oil Solidifier Performance and the Development of a New Empirical Correlation for Predicting Effectiveness

    Science.gov (United States)

    Temperature can play a significant role in the efficacy of solidifiers in removing oil slicks on water. We studied and quantified the effect of temperature on the performance of several solidifiers using 5 different types of oils under a newly developed testing protocol by conduc...

  2. 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.

  3. Structural reasons for the nonlinear optical properties of KTi{sub 0.96}Zr{sub 0.04}OPO{sub 4} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Novikova, N. E., E-mail: natnov@ns.crys.ras.ru; Verin, I. A.; Sorokina, N. I.; Alekseeva, O. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Agapova, E. I.; Voronkova, V. I. [Moscow State University (Russian Federation)

    2009-03-15

    This paper reports on the results of the precision X-ray structural investigations of KTi{sub 0.96}Zr{sub 0.04}OPO{sub 4} single crystals at room temperature. It is established that the incorporation of zirconium atoms into the structure of KTiOPO{sub 4} (KTP) crystals does not lead to substantial changes in the framework structure and results only in an insignificant decrease in the scatter of the distances in the PO{sub 4} tetrahedra and the formation of more symmetric (TiZr)O{sub 6} octahedra as compared to the TiO{sub 6} octahedra. However, the incorporation of zirconium atoms into the KTP structure is accompanied by the redistribution of the electron density in the crystal as a whole, so that the electron density increases in the region of the positions occupied by the potassium atoms. This changes the nonlinear optical properties of the given series of crystals, which are estimated from the intensity of the second harmonic generation signals.

  4. Volume and enthalpy relaxation in Zr{sub 55}Cu{sub 30}Ni{sub 5}Al{sub 10} bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Haruyama, O., E-mail: haruyama@ph.noda.tus.ac.jp [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, Noda 278-8510 (Japan); Nakayama, Y.; Wada, R. [Department of Physics, Faculty of Science and Technology, Tokyo University of Science, Noda 278-8510 (Japan); Tokunaga, H. [Department of Mechanical Engineering, Ube National College of Technology, Ube 755-8555 (Japan); Okada, J.; Ishikawa, T. [Institute of Space and Astronautical Science, Japan Aerospace, Exploration Agency, Tsukuba 305-8505 (Japan); Yokoyama, Y. [Institute of Materials Research, Tohoku University, Sendai 980-8577 (Japan)

    2010-03-15

    The structural relaxation in a Zr{sub 55}Cu{sub 30}Ni{sub 5}Al{sub 10} bulk metallic glass was investigated by volume and enthalpy relaxation at various temperatures. The relaxation kinetics was well described by a stretched exponential relaxation function, {Phi}(t)=exp[-(t/{tau}){sup {beta}}]. The Kohlrausch index, {beta}, ranged from 0.35 to 0.69, while the temperature dependence of relaxation time, {tau} was best fitted by the Vogel-Fulcher-Tanmmann formula, {tau}(T)={tau}{sub 0}exp[D{sup *}T{sub 0}/(T-T{sub 0})], with {tau}{sub 0} = 1.1 x 10{sup -14} s, D{sup *} = 44.2 and T{sub 0} = 311 K. Atomic volumes in the equilibrium liquid region were measured by the electrostatic levitation method and these volumes, together with volumes of relaxed glasses, were better described by the Cohen-Grest model than by the Cohen-Turnbull model.

  5. Structural and mechanical modifications induced on Cu{sub 47.5}Zr{sub 47.5}Al{sub 5} metallic glass by surface laser treatments

    Energy Technology Data Exchange (ETDEWEB)

    Fornell, J., E-mail: jordina.fornell@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Pellicer, E. [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Garcia-Lecina, E., E-mail: egarcia@cidetec.es [Surfaces Division, IK4-CIDETEC, Parque Tecnológico de San Sebastián, 20009 Donostia (Spain); Nieto, D. [Surfaces Division, IK4-CIDETEC, Parque Tecnológico de San Sebastián, 20009 Donostia (Spain); Suriñach, S.; Baró, M.D. [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Sort, J. [Institució Catalana de Recerca i Estudis Avançats and Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain)

    2014-01-30

    We have investigated the effects of surface laser treatment (SLT) on the structure, mechanical properties and wettability of Cu{sub 47.5}Zr{sub 47.5}Al{sub 5} metallic glass alloy. SLT has been carried out at three different intensities with the aim of inducing variable surface damage and tuneable changes in the resulting properties. X-ray diffraction characterization and scanning electron microscopy observations reveal that the alloy laser treated at 28.5 A remains amorphous while the alloy treated at 29 A becomes partially crystalline (CuZr B2 phase). When the alloy is treated at 30 A, it is mainly composed of copper and zirconium oxides. Nanoindentation tests, carried out on-top of the as-cast and laser-treated surfaces, reveal that SLT at 28.5 A causes an increase in hardness, which can be attributed to annihilation of free volume (i.e. structural relaxation). Conversely, hardness values of the alloy laser-treated at 29 A are almost the same as those of the as-cast alloy. This could be ascribed to the counterbalance effect between the softer nature of the CuZr B2 phase and the harder nature of the remaining relaxed amorphous phase. Larger hardness values are observed for the alloy laser treated at 30 A as a result of oxide phase formation.

  6. Rapid solidification of Nb-base alloys

    Science.gov (United States)

    Gokhale, A. B.; Javed, K. R.; Abbaschian, G. J.; Lewis, R. E.

    1988-01-01

    New Nb-base alloys are of interest for aerospace structural applications at high temperatures, viz, 800 to 1650 C. Fundamental information regarding the effects of rapid solidification in achieving greatly refined microstructures, extended solid solubility, suppression of embrittling equilibrium phases, and formation of new phases is desired in a number of Nb-X alloys. The microstructures and selected properties of Nb-Si and other Nb-base alloys are presented for materials both rapidly quenched from the equilibrium liquidus and rapidly solidified following deep supercooling. Electromagnetic levitation was used to achieve melting and supercooling in a containerless inert gas environment. A variety of solidification conditions were employed including splatting or drop casting of supercooled samples. The morphology and composition of phases formed are discussed in terms of both solidification history and bulk composition.

  7. 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.

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

    Science.gov (United States)

    Zhu, Yuping; Chen, Tao; Teng, Yao; Liu, Bingfei; Xue, Lijun

    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.

  9. Morphological instability of lamellar structures in directionally solidified Ni-Ni3Si alloys

    Science.gov (United States)

    Wei, Lufeng; Zhao, Zhilong; Gao, Jianjun; Cui, Kai; Guo, Jingying; Chen, Sen; Liu, Lin

    2018-02-01

    The morphological instability of lamellar structures in Ni-Ni3Si eutectic and hypereutectic alloys directionally solidified at low growth rates was investigated. The first instability in large lamellar structures was zigzag instability, which formed curved lamellae. A zigzag pattern was first displayed in three dimensions. The diffusion-limited growth of the Ni3Si phase decreased phase width and spacing, consequently causing zigzag instability. The reduced spacing was observed at λ/λave = 0.9. After zigzag instability, the microstructure of the eutectic alloy turned into a labyrinth structure and lamellar fragmentation. However, in hypereutectic alloys, shape transition from lamellae to rods occurred, in turn, by the broken lamellae or elongated rods to dumbbell-shaped rods, peanut-shaped rods, and circular rods.

  10. 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.

  11. 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

    2016-04-01

    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.

  12. Microstructural Development in Al-Ni Alloys Directionally Solidified under Unsteady-State Conditions

    Science.gov (United States)

    Canté, Manuel V.; Spinelli, José E.; Ferreira, Ivaldo L.; Cheung, Noé; Garcia, Amauri

    2008-07-01

    Three Al-Ni hypoeutectic alloys were directionally solidified under upward unsteady-state heat-flow conditions. Primary ( λ 1) and secondary ( λ 2) dendrite arm spacings were measured along the castings for all alloys and correlated with transient solidification thermal variables. A combined theoretical and experimental approach was used to quantitatively determine such thermal variables, i.e., transient metal/mold heat-transfer coefficients, tip growth rates, thermal gradients, tip cooling rates, and local solidification time. The article also focuses on the dependence of dendrite arm spacings on the alloy solute content. Furthermore, the experimental data concerning the solidification of Al-1.0, 2.5, and 4.7 wt pct Ni alloys are compared with the main predictive dendritic models from the literature.

  13. The correlation between dendritic microstructure and mechanical properties of directionally solidified hypoeutectic Al-Ni alloys

    Science.gov (United States)

    Canté, Manuel V.; Spinelli, José E.; Cheung, Noé; Garcia, Amauri

    2010-02-01

    Al-Ni hypoeutectic alloys were directionally solidified under upward transient heat flow conditions. The aim of the present study is to set up correlations between the as-cast microstructure and the resulting mechanical properties of these alloys. The dependence of primary and secondary dendrite arm spacing on the alloy solute content and on solidification thermal parameters is also analyzed. The results include transient metal/mold heat transfer coefficient, tip growth rate, cooling rate, dendrite arm spacing, ultimate tensile strength, yield tensile strength and elongation. Expressions relating dendrite spacing to solidification thermal parameters and mechanical properties to the scale of the dendritic microstructure have been determined. It was found that the ultimate tensile strength and the yield tensile strength increase with increasing alloy solute content and with decreasing primary and secondary dendrite arm spacing. In contrast, the elongation was found to be independent of both alloy composition and dendritic arrangement.

  14. 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

  15. Leaching behavior and immobilization of heavy metals in solidified/stabilized products.

    Science.gov (United States)

    Malviya, Rachana; Chaudhary, Rubina

    2006-09-01

    Solidification/stabilization (S/S) of hazardous sludge from steel processing plant has been studied. Mechanical strength and leaching behavior test of solidified/stabilized product was performed. Mechanical strength decreases with increase in waste content. Pb, Zn, Cu, Fe and Mn could be considerably immobilized by the solidification/stabilization process. The elements least immobilized were Na, K, and Cl. Leaching of heavy metals in the S/S matrix can be considered as pH dependent and corresponding metal hydroxide solubility controlled process. Geochemical modeling was performed for the prediction of speciation. On the basis of test results, mobility and mechanism of leaching was assessed. Dominant leaching mechanism was surface wash off in the initial stages followed by diffusion for Pb, Zn, Cu, Fe and Mn. Diffusion coefficient was above 11.5 indicating low mobility in the cement matrix.

  16. 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.

  17. 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.

  18. Strain hardening and fracture behavior during tension of directionally solidified high-nitrogen austenitic steel

    Science.gov (United States)

    Maier, Galina; Astafurova, Elena; Melnikov, Eugene; Moskvina, Valentina; Galchenko, Nina

    2017-12-01

    The effect of grain orientation relative to tensile load on the strain hardening behavior and fracture mechanism of directionally solidified high-nitrogen steel Fe-20Cr-22Mn-1.5V-0.2C-0.6N (in wt %) was studied. The tensile samples oriented along the longitudinal direction of columnar grains demonstrated the improved mechanical properties compared to specimens with the transversal directions of columnar grains: the values of tensile strength and strain-to-fracture were as high as 1080 MPa and 22%, respectively, for tension along the columnar grains and 870 MPa and 11%, respectively, for the tension transversal to the columnar grains. The change in the grain orientation relative to the tensile load varies a fracture mode of the steel. The fraction of the transgranular fracture was higher in the samples with longitudinal directions of the columnar grains compared to the transversal ones.

  19. Microstructural evolution and corrosion behavior of directionally solidified FeCoNiCrAl high entropy alloy

    Directory of Open Access Journals (Sweden)

    Cui Hongbao

    2011-08-01

    Full Text Available The FeCoNiCrAl alloys have many potential applications in the fields of structural materials, but few attempts were made to characterize the directional solidification of high entropy alloys. In the present research, the microstructure and corrosion behavior of FeCoNiCrAl high entropy alloy have been investigated under directional solidification. The results show that with increasing solidification rate, the interface morphology of the alloy evolves from planar to cellular and dendritic. The electrochemical experiment results demonstrate that the corrosion products of both non-directionally and directionally solidified FeCoNiCrAl alloys appear as rectangular blocks in phases which Cr and Fe are enriched, while Al and Ni are depleted, suggesting that Al and Ni are dissolved into the NaCl solution. Comparison of the potentiodynamic polarization behaviors between the two differently solidified FeCoNiCrAl high entropy alloys in a 3.5%NaCl solution shows that the corrosion resistance of directionally solidified FeCoNiCrAl alloy is superior to that of the non-directionally solidified FeCoNiCrAl alloy.

  20. The effect of B-site substitution on structural transformation and ionic conductivity in Ho{sub 2}(Zr{sub y}Ti{sub 1−y}){sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Shafique, Muhammad [Materials Research Laboratory, Department of Physics, University of Peshawar, 25120 (Pakistan); Kennedy, Brenden J. [School of Chemistry, The University of Sydney, Sydney, NSW, 2006 (Australia); Iqbal, Yaseen, E-mail: dryaseeniqbal@yahoo.co.uk [Materials Research Laboratory, Department of Physics, University of Peshawar, 25120 (Pakistan); Ubic, Rick [College of Engineering, Boise State University, Boise, ID (United States)

    2016-06-25

    Compounds in the pyrochlore system Ho{sub 2}(Zr{sub y}Ti{sub 1−y}){sub 2}O{sub 7} exhibit an order-disorder transition from pyrochlore to a defect-fluorite type structure. Compositions in this system were prepared via mechanical milling, followed by a two-step sintering process. Structural characterization was carried out via Rietveld refinements using neutron powder diffraction data, supported by X-ray diffraction to determine the phase and location of the pyrochlore-fluorite transformation. Unit-cell parameters were determined for the whole series using Rietveld refinements as well as the Nelson–Riley function. The neutron refinement results confirmed that the cation disorder was independent of the anion Frenkel disorder. The relation between the x-parameter in the oxygen 48f position and anion Frenkel disorder was found to be linear for the pyrochlore structure. The ionic conductivity studies were undertaken via AC impedance analysis to determine the electronic behaviour and its relation to the structural change in the temperature range 300°C–700 °C. The trends in ionic conductivity and activation energy were explained structurally via neutron powder diffraction and X-ray diffraction data. The pyrochlore-fluorite boundary composition (at y = 0.5) exhibited the lowest activation energy and highest ionic conductivity. - Highlights: • Ho{sub 2}(Zr{sub y}Ti{sub 1-y}){sub 2}O{sub 7} structure changed from ordered pyrochlore to defect-fluorite at y = 0.6. • Ho{sub 2}(Zr{sub 0.5}Ti{sub 0.5}){sub 2}O{sub 7} exhibited high ionic conductivity and low activation energy. • Doping improved stability in ionic conductivity behaviour at lower temperature.

  1. Rapid solidification via melt spinning - Equipment and techniques

    Science.gov (United States)

    Jech, R. W.; Moore, T. J.; Glasgow, T. K.; Orth, N. W.

    1984-01-01

    One of the simpler methods available to accomplish rapid solidification processing is free jet melt spinning. With only a modest expenditure of time, effort, and capital, an apparatus suitable for preliminary experimentation can be assembled. Wheel and crucible materials, process atmospheres, crucible design, heating methods, and process parameters and their relationship to melt composition are described. Practical solutions to processing problems, based on 'hands-on' experience, are offered. Alloys with melting points up to 3000 F have been rapidly solidified using the techniques described.

  2. 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

  3. 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.

  4. 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

  5. Increased corrosion resistance of the AZ80 magnesium alloy by rapid solidification.

    Science.gov (United States)

    Aghion, E; Jan, L; Meshi, L; Goldman, J

    2015-11-01

    Magnesium (Mg) and Mg-alloys are being considered as implantable biometals. Despite their excellent biocompatibility and good mechanical properties, their rapid corrosion is a major impediment precluding their widespread acceptance as implantable biomaterials. Here, we investigate the potential for rapid solidification to increase the corrosion resistance of Mg alloys. To this end, the effect of rapid solidification on the environmental and stress corrosion behavior of the AZ80 Mg alloy vs. its conventionally cast counterpart was evaluated in simulated physiological electrolytes. The microstructural characteristics were examined by optical microscopy, SEM, TEM, and X-ray diffraction analysis. The corrosion behavior was evaluated by immersion, salt spraying, and potentiodynamic polarization. Stress corrosion resistance was assessed by Slow Strain Rate Testing. The results indicate that the corrosion resistance of rapidly solidified ribbons is significantly improved relative to the conventional cast alloy due to the increased Al content dissolved in the α-Mg matrix and the correspondingly reduced presence of the β-phase (Mg17 Al12 ). Unfortunately, extrusion consolidated solidified ribbons exhibited a substantial reduction in the environmental performance and stress corrosion resistance. This was mainly attributed to the detrimental effect of the extrusion process, which enriched the iron impurities and increased the internal stresses by imposing a higher dislocation density. In terms of immersion tests, the average corrosion rate of the rapidly solidified ribbons was <0.4 mm/year compared with ∼2 mm/year for the conventionally cast alloy and 26 mm/year for the rapidly solidified extruded ribbons. © 2014 Wiley Periodicals, Inc.

  6. 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

  7. 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.

  8. 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.

  9. Comparative Investigation of the Downward and Upward Directionally Solidified Single-Crystal Blades of Superalloy CMSX-4

    Science.gov (United States)

    Wang, Fu; Ma, Dexin; Bogner, Samuel; Bührig-Polaczek, Andreas

    2016-05-01

    Single-crystal blades of Ni-base superalloys CMSX-4 have been directionally solidified using the downward directional solidification (DWDS) process. The possible benefits of the process were comparatively evaluated with respect to the Bridgman process' results. The DWDS process exhibits good capabilities for casting the single-crystal components. The thermal gradients of this process are approximately seven times higher than those of the Bridgman process. It provides more advantages for solidifying the single-crystal superalloy blades by reducing the casting defects, refining the microstructure, decreasing the size of the γ/ γ' eutectic pools, refining the γ' precipitates, alleviating the degree of the microsegregation, and minimizing the size and volume fraction of the micropores.

  10. The influence of melt convection on dendritic spacing of downward unsteady-state directionally solidified Sn-Pb alloys

    Directory of Open Access Journals (Sweden)

    José Eduardo Spinelli

    2006-03-01

    Full Text Available Microstructures are the strategic link between materials processing and materials behavior. A dendritic structure is the most frequently observed pattern of solidified alloys. The microstructural scales of dendrites, such as primary and secondary arm spacings, control the segregation profiles and the formation of secondary phases within interdendritic regions, determine the properties of cast structures. In this work, the influence of thermosolutal convection on dendrite arm spacings is experimentally examined in the downward vertical unsteady-state directional solidification of Sn-Pb hypoeutectic alloys. The experimental observations are compared not only with the main predictive theoretical models for dendritic spacings but also with experimental results obtained for Sn-Pb alloys solidified vertically upwards. Primary dendritic arm spacings have been affected by the direction of growth, decreasing in conditions of downward vertical solidification when compared with those grown vertically upwards. Further, the unsteady-state lambda1 predictive models did not generate the experimental observations.

  11. A SEM and X-ray study for investigation of solidified/stabilized arsenic-iron hydroxide sludge.

    Science.gov (United States)

    Phenrat, Tanapon; Marhaba, Taha F; Rachakornkij, Manaskorn

    2005-02-14

    Despite the fact that the solidification/stabilization of arsenic containing wastes with Portland cement and lime has an extensively documented history of use, the physical and chemical phenomena as a result of the interaction between arsenic and cement components have not been fully characterized. The study investigates the behavior of synthesized arsenic-iron hydroxide sludge, the by-product of arsenic removal by coagulation with ferric chloride, in solidified/stabilized matrices as well as its binding mechanisms by exploring the cementitious matrices in the micro-scale by scanning electron microscopy equipped with energy dispersive X-ray spectrometer (SEM-EDS). It was revealed that arsenic can be chemically fixed into cementitious environment of the solidified/stabilized matrices by three important immobilization mechanisms; sorption onto C-S-H surface, replacing SO4(2-) of ettringite, and reaction with cement components to form calcium-arsenic compounds, the solubility limiting phases.

  12. Structure, morphology and optical properties of multilayered sol-gel BaTi{sub 0.85}Zr{sub 0.15}O{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Vasilescu, Catalina A. [Polytechnics University of Bucharest, Department of Oxide Materials Science and Engineering, 1-7 Gh. Polizu, P.O. Box 12-134, 011061 Bucharest (Romania); Crisan, Maria, E-mail: mcrisan@icf.ro [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Ianculescu, Adelina C., E-mail: a.ianculescu@yahoo.com [Polytechnics University of Bucharest, Department of Oxide Materials Science and Engineering, 1-7 Gh. Polizu, P.O. Box 12-134, 011061 Bucharest (Romania); Raileanu, Malina; Gartner, Mariuca [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Anastasescu, Mihai, E-mail: manastasescu@icf.ro [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Dragan, Nicolae; Crisan, Dorel [Ilie Murgulescu Institute of Physical Chemistry, Romanian Academy, 202 Splaiul Independentei, 060021 Bucharest (Romania); Gavrila, Raluca [National Institute of Microtechnologies, 32B Erou Iancu Nicolae, P.O. Box 38-160, 77190 Bucharest (Romania); Trusca, Roxana [S.C. METAV - Research and Development Bucharest, 31 C. A. Rosetti, 020011 Bucharest (Romania)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Multilayered BaTi{sub 0.85}Zr{sub 0.15}O{sub 3} sol-gel films coated on silicon wafers were performed. Black-Right-Pointing-Pointer Structure, surface topography and optical properties were investigated. Black-Right-Pointing-Pointer Perovskite BTZ phase were noted only in the thicker multilayer films (BTZ4-BTZ6). Black-Right-Pointing-Pointer A smaller roughness value was obtained for the six deposits BTZ film. Black-Right-Pointing-Pointer Multilayer BTZ films present a more uniform distribution of the average grain size. - Abstract: Continuous and homogeneous multilayered BaTi{sub 0.85}Zr{sub 0.15}O{sub 3} (BTZ) films were prepared by the sol-gel method and deposited on SiO{sub 2}/Si substrates. X-ray diffraction analysis indicated the presence of well-crystallized, single phase perovskite BTZ phase only in the thicker, multilayer films (with more than three deposits). Beside the shrinkage of the unit cell, the increase of the deposits number in the BTZ films also induced an obvious surface smoothing, a higher compactness and a more uniform distribution of the average grain size, as observed by SEM and AFM investigations. The refractive index showed normal values indicating a high crystallinity degree for the films under investigation.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Effects of Rapid Solidification Process and 0.1 wt.% Pr Addition on Properties of Sn-9Zn Alloy and Cu/Solder/Cu Joints

    Science.gov (United States)

    Zhao, Guoji; Jing, Yanxia; Sheng, Guangmin; Chen, Jianhua

    2016-05-01

    Effects of 0.1 wt.% Pr addition and rapid solidification process on Sn-9Zn solder alloy were investigated. Solder characteristics of the as-solidified and rapidly solidified Sn-9Zn-0.1Pr alloys were analyzed in comparison with those of the as-solidified Sn-9Zn alloy. Mechanical properties and interfacial microstructure of solder/Cu joints obtained using these solders were comparatively studied. By comparison with the as-solidified Sn-9Zn alloy, the wettability of the solder was obviously improved with 0.1 wt.% Pr addition, and the melting behavior of the solder was promoted due to the rapid solidification process. The corrosion resistance of Sn-9Zn-0.1Pr alloy was improved due to the refined microstructure resulting from 0.1 wt.% Pr addition and rapid solidification. The growth of IMCs at the interface of Sn-9Zn-0.1Pr/Cu joints was depressed in some degree. Rapid solidification process promoted the interfacial reaction during soldering and improved the bonding strength of joints.

  18. 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

  19. Effect of a weak transverse magnetic field on the microstructure in directionally solidified peritectic alloys

    Science.gov (United States)

    Li, Xi; Lu, Zhenyuan; Fautrelle, Yves; Gagnoud, Annie; Moreau, Rene; Ren, Zhongming

    2016-11-01

    Effect of a weak transverse magnetic field on the microstructures in directionally solidified Fe-Ni and Pb-Bi peritectic alloys has been investigated experimentally. The results indicate that the magnetic field can induce the formation of banded and island-like structures and refine the primary phase in peritectic alloys. The above results are enhanced with increasing magnetic field. Furthermore, electron probe micro analyzer (EPMA) analysis reveals that the magnetic field increases the Ni solute content on one side and enhances the solid solubility in the primary phase in the Fe-Ni alloy. The thermoelectric (TE) power difference at the liquid/solid interface of the Pb-Bi peritectic alloy is measured in situ, and the results show that a TE power difference exists at the liquid/solid interface. 3 D numerical simulations for the TE magnetic convection in the liquid are performed, and the results show that a unidirectional TE magnetic convection forms in the liquid near the liquid/solid interface during directional solidification under a transverse magnetic field and that the amplitude of the TE magnetic convection at different scales is different. The TE magnetic convections on the macroscopic interface and the cell/dendrite scales are responsible for the modification of microstructures during directional solidification under a magnetic field.

  20. Tensile behavior of directionally solidified Ni3Al intermetallics with different Al contents and solidification rates

    Science.gov (United States)

    Lu, Yun; Gu, Jiho; Kim, Sangshik; Hong, Hyunuk; Choi, Heekyu; Lee, Jehyun

    2014-03-01

    Despite the excellent high temperature mechanical properties of the Ni3Al intermetallic compound, its application is still limited due to its inherently weak grain boundary. Recent research advances have demonstrated that the tensile ductility can be enhanced by controlling the grain morphology using a directional solidification. In this study, a series of directional solidification experiments were carried out to increase both the tensile ductility and the strength of Ni3Al alloys by arraying either the ductile phase of γ-Ni-rich dendrite fibers or the hard phase of β-NiAl dendrite fibers in the γ'-Ni3Al matrix. The dendrite arm spacing could be controlled by the solidification rate, and the volume fraction of the γ or β phase could be altered by the Al content, ranging from 23 at.% to 27 at.%. With an increasing Al content, the γ dendritic microstructure was transformed into the β dendrite in the γ' matrix, thereby reducing the tensile ductility by increasing the volume fraction of brittle β dendrites in the γ' matrix. With an increasing solidification rate, the dendrite arm spacing decreased and the tensile properties of Ni3Al varied in a complex manner. The microstructural evolution affecting the tensile behavior of directionally solidified Ni3Al alloy specimens with different solidification rates and Al contents is discussed.

  1. 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.

  2. Microstructure Control of Columnar-Grained Silicon Substrate Solidified from Silicon Melts Using Gas Pressure

    Directory of Open Access Journals (Sweden)

    Jun-Kyu Lee

    2015-01-01

    Full Text Available A silicon substrate with the dimensions of 100 × 140 × 0.3 mm was grown directly from liquid silicon with gas pressure. The silicon melt in the sealed melting part was injected into the growth part at applied pressure of 780–850 Torr. The solidified silicon substrate was then transferred by the pull of the cooled dummy bar. A desirable structure with a liquid-solid interface perpendicular to the pulling direction was formed when the mold temperature in the solidification zone of the growth part was much higher than that of the dummy bar, as this technique should be able to overcome thermal loss through the molds and the limited heat flux derived from the very narrow contact area between the silicon melt and the dummy bar. In addition, because the metallic impurities and expansion of volume during solidification are preferably moved to a liquid phase, a high-quality silicon substrate, without defects such as cracks and impurities in the substrate, could be manufactured in the interface structure. The present study reports the experimental findings on a new and direct growth system for obtaining silicon substrates characterized by high quality and productivity, as a candidate for alternate routes for the fabrication of silicon substrates.

  3. High-temperature performance evaluation of adirectionally solidified nickel-base superalloy

    Science.gov (United States)

    Woodford, D. A.; Stiles, D.

    1997-08-01

    The application of a new approach, design for performance, for high-temperature alloy development, design analysis, and remaining life assessment, based on short-time high-precision testing, is described in this paper. The material tested was a directionally solidified nickel-base alloy, GTD111. It was found that the creep strength at 850 °C was indeed superior to that of a competitive alloy, IN738, but was not necessarily enhanced by the preferred alignment of grain boundaries and crystal orientation. In contrast, the fracture resistance at 800 °C was improved in the longitudinal direction compared with transverse and diagonal orientations in terms of susceptibility to gas phase embrittlement (GPE) by oxygen. Specimens cut transversely and diagonally to the growth direction were more sensitive to GPE than specimens taken from conventionally cast IN738. The new conceptual framework allows account to be taken of GPE and other embrittling phenomena, which may develop in service, leading to rational life management decisions for gas turbine users. Additionally, straightforward design analysis procedures can be developed from the test data, which for the first time allow separate measurements of creep strength and fracture resistance to be used for performance evaluation.

  4. Massive, solidified bone in the wing of a volant courting bird.

    Science.gov (United States)

    Bostwick, Kimberly S; Riccio, Mark L; Humphries, Julian M

    2012-10-23

    One pervasive morphological feature of tetrapods is the pipe-like, often marrow-filled, structure of the limb or long bones. This 'hollow' form maximizes flexural strength and stiffness with the minimum amount of bony material, and is exemplified by truly hollow (air-filled), or pneumatic, humeri in many modern birds. High-resolution microCT scans of the wings of two male club-winged manakins (Machaeropterus deliciosus) uncovered a notable exception to the hollow-tube rule in terrestrial vertebrates; males exhibited solidified ulnae more than three times the volume of birds of comparable body size, with significantly higher tissue mineral densities. The humeri exhibited similar (but less extreme) modifications. Each of the observed osteological modifications increases the overall mass of the bone, running counter to pervasive weight-reducing optimizations for flight in birds. The club-winged manakin is named for a pair of unique wing feathers found in adult males; these enlarged feathers attach directly to the ulna and resonate to produce a distinctive sound used in courtship displays. Given that the observed modifications probably assist in sound production, the club-winged manakin represents a case in which sexual selection by female choice has generated an ecologically 'costly' forelimb morphology, unique in being specialized for sound production at a presumed cost in flight efficiency.

  5. Primary arm spacing in directionally solidified Pb-10 wt pct Sn alloys

    Science.gov (United States)

    Chopra, M. A.; Tewari, S. N.

    1990-01-01

    The dependence of primary arm spacings on growth speed was investigated for cellular and dendritic arrays in Pb-10 wt percent Sn samples directionally solidified under a constant positive thermal gradient in the melt. The gradient of constitutional supercooling was varied from almost zero (near the break-down of the planar liquid-solid interface at small growth speeds, cellular morphology) to near unity (large growth speeds, dendritic morphology). The spatial arrangements of cells and dendrites, as given by their coordination number, are not very different from each other. It appears that primary arm spacing maxima and the cell to dendrite transition are strongly influenced by the magnitude of the solute partition coefficient. The planar to cellular bifurction is supercritical in Pb-Sn which has a high partition coefficient, as compared to the subcritical behavior reported in Al-Cu and succinonitrile-acetone, both of which have low partition coefficients. The primary arm spacing model due to Hunt agrees with the experimentally observed trend for the whole growth regime. There is a good quantitative agreement at higher grdients of supercooling. However, the model overpredicts the primary arm spacings at low gradients of constitutional supercooling.

  6. 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.

  7. Multi-scale Constitutive Model of Solidifying Cementitious Composites and Application to Cracking Assessment of a Concrete Structure

    OpenAIRE

    石田, 哲也; 浅本, 晋吾; 前川, 宏一

    2006-01-01

    A multi-scale constitutive model of solidifying cementitious materials is presented based on a systematic knowledge coupling structural mechanics with chemo-physical phenomena. The model can reasonably simulate time-dependent deformations such as autogenous/drying shrinkage and basic/drying creep in laboratory tests under arbitrary environmental and loading conditions. Shrinkage induced cracking in an actual PRC bridge structure was examined by the analytical system, which reveals that large ...

  8. 46 CFR 153.1108 - Heated prewash for solidifying NLS, high viscosity NLS and required prewashes of NLS whose...

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Heated prewash for solidifying NLS, high viscosity NLS and required prewashes of NLS whose viscosity exceeds 25 mPa sec at 20 °C: Categories A, B, and C. 153.1108 Section 153.1108 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID,...

  9. Synthesis, structural and morphological characterization of Ca{sub 0}.45Eu{sub 0}.05Zr{sub 2}(PO{sub 4}){sub 3} nano phosphors; Sintesis, caracterizacion estructural y morfologica de nanofosforos Ca {sub 0},45Eu{sub 0},05Zr{sub 2}(PO{sub 4}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, L.; Isasi, J.; Peiteado, M.; Cabalero, A.

    2015-07-01

    Ca{sub 0}.45Eu{sub 0}.05Zr{sub 2}(PO{sub 4}){sub 3} samples were synthesized by a preparation process in two step: a sol-gel method using two pH values, acid (pH ∼ 2) and basic pH (∼ 10), and a subsequent treatment of the precursor powders in a N{sub 2}:H{sub 2} (90:10) flow in order to stabilized 2+ oxidation state of europium. X-ray diffraction patterns exhibit diffraction maxima typical of NASICON type structure of rhombohedral symmetry and space group R-3. Most intense diffraction maxima are seen for the samples prepared in a basic reaction medium. Magnetic measurements confirm 2+ oxidation state of europium cations in the synthesized samples. Microscopy images show particles of spherical shape and nano metric size according to X-ray diffraction results, indicating that these samples may be useful in certain luminescent devices. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, R.D.; Hamilton, M.A.; Veeh, R.H.; McConnell, J.W. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1994-12-31

    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.

  11. Studies on uniformity of the active ingredients in acetaminophen suppositories re-solidified after melting under high temperature conditions.

    Science.gov (United States)

    Yamamoto, Yoshihisa; Fukami, Toshiro; Koide, Tatsuo; Onuki, Yoshinori; Suzuki, Toyofumi; Katori, Noriko; Tomono, Kazuo

    2015-01-01

    The target of the present pharmaceutical study was the antipyretic analgesic, acetaminophen; its suppository form is usually split when used in pediatric patients. We focused on the active ingredient uniformity in these products, which were re-solidified after melting under high temperature condition. When sections of the cut surfaces of the seven acetaminophen suppository products (SUP-A-G) commercially available in Japan were visualized by polarized microscopy, acetaminophen crystals that were dispersed in the base were identified. The results of the quantitative determination of agent concentration for each cut portion (mg/g) suggested uniform dispersion of these crystals in the base of each product. The agent concentration in each portion of the suppositories that was re-solidified after melting at high temperatures was measured. Segregation of the active ingredient was observed in four products at a temperature of 40°C for 1 h, while active ingredient uniformity was maintained in the other three products (SUP-C, SUP-F and SUP-G). The latter three products also showed high viscosity at 40°C. At 50°C for 4 h, only the uniformity of the active ingredient in SUP-C was maintained. These results suggest that the uniformity of the active ingredient is lost in some acetaminophen suppositories that were re-solidified after melting under high temperature conditions. The degree of loss varies depending on the product.

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

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Hema, E-mail: hhasija@gmail.com [TERI University, Plot No. 10, Institutional Area, Vasant Kunj, New Delhi (India); Pandey, Suneel [Centre for Regulatory and Policy Research, The Energy and Resources Institute (TERI), India Habitat Centre, New Delhi (India)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Stabilization/solidification of chemical sludge from textile wastewater treatment plants using Portland Pozzolona Cement (PPC) containing fly ash. Black-Right-Pointing-Pointer Physical engineering (compressive strength and block density) indicates that sludge has potential to be reused for construction purpose after stabilization/solidification. Black-Right-Pointing-Pointer Leaching of heavy metals from stabilized/solidified materials were within stipulated limits. Black-Right-Pointing-Pointer 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{sup 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.

  13. The relationship of microstructure to fracture and corrosion behavior of a directionally solidified superalloy

    Science.gov (United States)

    Trexler, Matthew D.

    GTD-111 DS is a directionally solidified superalloy currently used in turbine engines. To accurately predict the life of engine components it is essential to examine and characterize the microstructural evolution of the material and its effects on material properties. The as-cast microstructure of GTD-111 is highly inhomogeneous as a result of coring. The current post-casting heat treatments do not effectively eliminate the inhomogeneity. This inhomogeneity affects properties including tensile strength, fracture toughness, fracture path, and corrosion behavior, primarily in terms of the number of grains per specimen. The goal of this work was to link microstructural features to these properties. Quantitative fractography was used to determine that the path of cracks during failure of tensile specimens is influenced by the presence of carbides, which are located in the interdendritic regions of the material as dictated by segregation. The solvus temperature of the precipitate phase, Ni3(Al, Ti), was determined to be 1200°C using traditional metallography, differential thermal analysis, and dilatometry. A heat-treatment was designed to homogenize the microstructure for tensile testing that isolates the carbide by dissolving all of the "eutectic" Ni3(Al, Ti) precipitate phase, which is also found in the interdendritic areas. High temperature oxidation/sulfidation tests were conducted to investigate the corrosion processes involved when GTD-111 DS is utilized in steam and gas combustion turbine engines. The kinetics of corrosion in both oxidizing and sulfidizing atmospheres were determined using thermogravimetric analysis. Additionally, metallography of these samples after TGA revealed a correlation between the presence of grain boundaries and sulfur attack, which led to catastrophic failure of the material under stress-free conditions in a sulfur bearing environment. In summary, this work correlates the inhomogeneous microstructure of GTD-111 DS to tensile fracture

  14. Microstructural evolution of directionally solidified DZ125 superalloy castings with different solidification methods

    Directory of Open Access Journals (Sweden)

    Ge Bingming

    2013-01-01

    Full Text Available The properties of Ni-base superalloy castings are closely related to the uniformity of their as-cast microstructure, and different solidification methods have serious effect on microstructural uniformity. In this paper, the influences of high rate solidification (HRS process (with or without superheating and liquid metal cooling (LMC process on the microstructure of DZ125 superalloy were investigated. Blade-shape castings were solidified at rates of 40 μm·s-1 to 110 μm·s-1 using HRS process and a comparative experiment was carried out at a rate of 70 μm·s-1 by LMC process. The optical microscope (OM, scanning electron microscope (SEM were used to observe the microstructure and the grain size was analyzed using electron back scattered diffraction (EBSD technique. Results show that for the castings by either HRS or LMC process, the primary dendrite arm spacing and size of γ' precipitates decrease with increasing the withdrawal rate; the dendrites and γ' precipitates at the upper section of the blade are coarser than those in the middle, especially for the HRS castings without high superheating technique. When the withdrawal rate is 70 μm·s-1, the castings by HRS with high superheating technique have the smallest PDAS with fine γ' precipitates; while the size distribution of γ' precipitates is more homogenous in LMC castings, and the number of larger grains in LMC castings is smaller than that in the HRS castings. Moreover, high superheating technique yields smaller grains in the castings. Both the LMC method and HRS with high superheating technique can be used to prepare castings with reduced maximum grain size.

  15. 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

  16. Thermoelectric properties of TiNiSn and Zr{sub 0.5}Hf{sub 0.5}NiSn thin films and superlattices with reduced thermal conductivities

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Tino

    2013-08-21

    Rising energy costs and enhanced CO{sub 2} emission have moved research about thermoelectric (TE) materials into focus. The suitability of a material for usage in TE devices depends on the figure of merit ZT and is equal to α{sup 2}σTκ{sup -1} including Seebeck coefficient α, conductivity σ, temperature T and thermal conductivity κ. Without affecting the power factor α{sup 2}σ, using nanostructuring, ZT should here be increased by a depressed thermal conductivity. As half-Heusler (HH) bulk materials, the TE properties of TiNiSn and Zr{sub 0.5}Hf{sub 0.5}NiSn have been extensively studied. Here, semiconducting TiNiSn and Zr{sub 0.5}Hf{sub 0.5}NiSn thin films were fabricated for the first time by dc magnetron sputtering. On MgO (100) substrates, strongly textured polycrystalline films were obtained at substrate temperatures of about 450 C. The film consisted of grains with an elongation perpendicular to the surface of 55 nm. These generated rocking curves with FWHMs of less than 1 . Structural analyses were performed by X ray diffraction (XRD). Having deposition rates of about 1 nms{sup -1} within shortest time also films in the order of microns were fabricated. For TiNiSn the highest in-plane power factor of about 0.4 mWK{sup -2}m{sup -1} was measured at about 550 K. In addition, at room temperature a cross-plane thermal conductivity of 2.8 Wm{sup -1}K{sup -1} was observed by the differential 3ω method. Because the reduction of thermal conductivity by mass fluctuation is well-known and interface scattering of phonons is expected, superlattices (SL) were fabricated. Therefore, TiNiSn and Zr{sub 0.5}Hf{sub 0.5}NiSn were successively deposited. While the sputter cathodes were continuously running, for fabrication of SLs the substrates were moved from one to another. The high crystal quality of the SLs and the sharp interfaces were proven by satellite peaks (XRD) and Scanning Transmission Electron Microscopy (STEM). For a SL with a periodicity of 21 nm (Ti

  17. Structure of the RbTi{sub 0.98}Zr{sub 0.02}OPO{sub 4} single crystal at temperatures of 293 and 105 K

    Energy Technology Data Exchange (ETDEWEB)

    Alekseeva, O. A., E-mail: olalex@ns.crys.ras.ru; Dudka, A. P.; Novikova, N. E.; Sorokina, N. I. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Agapova, E. I.; Voronkova, V. I. [Lomonosov Moscow State University (Russian Federation)

    2008-07-15

    This paper reports on the results of precision X-ray structural investigations of a RbTi{sub 0.98}Zr{sub 0.02}OPO{sub 4} single crystal at temperatures of 293 and 105 K. It is established that the observed decrease in the temperature of the ferroelectric phase transition in RbTiOPO{sub 4} crystals doped with zirconium is associated with the increase in the Rb-O bond lengths. The structural factors responsible for the decrease in the electrical conductivity in these crystals are revealed. An analysis is made of the structure of the helical channels which in crystals of this family are considered to be a decisive factor for the manifestation of superionic conduction. It is shown that, in structures of the KTiOPO{sub 4} (KTP) type, the migration of ions in channels is most hindered inside the cavities.

  18. 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)

  19. 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.

  20. Mechanical behavior and microstructure of Ti{sub 20}Hf{sub 20}Zr{sub 20}Ta{sub 20}Nb{sub 20} high-entropy alloy loaded under quasi-static and dynamic compression conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dirras, G., E-mail: dirras@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, LSPM-CNRS, UPR 3407, 99 avenue JB Clément, 93430 Villetaneuse (France); Couque, H. [Nexter-munitions, 7 Route de Guerry, 18200 Bourges (France); Lilensten, L. [Université Paris Est, ICMPE (UMR 7182), CNRS, UPEC, 94320 Thiais (France); Heczel, A. [Department of Materials Physics, Eötvös Loránd University, Budapest, P.O.B. 32, H-1518 (Hungary); Tingaud, D. [Université Paris 13, Sorbonne Paris Cité, LSPM-CNRS, UPR 3407, 99 avenue JB Clément, 93430 Villetaneuse (France); Couzinié, J.-P.; Perrière, L. [Université Paris Est, ICMPE (UMR 7182), CNRS, UPEC, 94320 Thiais (France); Gubicza, J. [Department of Materials Physics, Eötvös Loránd University, Budapest, P.O.B. 32, H-1518 (Hungary); Guillot, I. [Université Paris Est, ICMPE (UMR 7182), CNRS, UPEC, 94320 Thiais (France)

    2016-01-15

    The microstructure and the mechanical behavior of equimolar Ti{sub 20}Hf{sub 20}Zr{sub 20}Ta{sub 20}Nb{sub 20} high-entropy alloy in a wide range of initial strain rates between ~ 10{sup −3} s{sup −1} and ~ 3.4 × 10{sup 3} s{sup −1} were studied. A significant increment in the yield strength with increasing strain rate was observed. The yield strength at ~ 3.4 × 10{sup 3} s{sup −1} was about 40% higher than that measured at ~ 10{sup −3} s{sup −1}. Analysis by electron backscatter diffraction shows that in the low strain rate regime (up to ~ 10 s{sup −1}) the deformation occurs mainly in evenly distributed bands, while in the dynamic regime the deformation is strongly localized in macroscopic shear bands accompanied by softening even after the onset of yielding. The Kernel Average Misorientation technique reveals a high level of lattice rotation within these bands that also carries intense shear. In addition, X-ray diffraction line profile analysis indicates that the sharp increase in the flow stress is mostly related to an increase of the dislocation density. - Highlights: • Strain rate effect on the plastic behavior of Ti{sub 20}Hf{sub 20}Zr{sub 20}Ta{sub 20}Nb{sub 20} HEA was studied. • Low strain rate regime was characterized by a continuous hardening. • At high strain rates softening occurred shortly after the onset of yielding. • Intense strain localization in shear bands occurred in the high strain rate regime. • High dislocation density explained the upturn of flow stress at high strain rates.

  1. Microstructural investigation of plastically deformed Ti{sub 20}Zr{sub 20}Hf{sub 20}Nb{sub 20}Ta{sub 20} high entropy alloy by X-ray diffraction and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dirras, G., E-mail: dirras@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, LSPM (UPR 3407) CNRS, 99 avenue JB Clément, 93430 Villetaneuse (France); Gubicza, J.; Heczel, A. [Department of Materials Physics, Eötvös Loránd University, Budapest, P.O. Box 32, H-1518 (Hungary); Lilensten, L.; Couzinié, J.-P.; Perrière, L.; Guillot, I. [Université Paris Est, ICMPE (UMR 7182), CNRS, UPEC, 94320 Thiais (France); Hocini, A. [Université Paris 13, Sorbonne Paris Cité, LSPM (UPR 3407) CNRS, 99 avenue JB Clément, 93430 Villetaneuse (France)

    2015-10-15

    The microstructure evolution in body-centered cubic (bcc) Ti{sub 20}Zr{sub 20}Hf{sub 20}Nb{sub 20}Ta{sub 20} high entropy alloy during quasi-static compression test was studied by X-ray line profile analysis (XLPA) and transmission electron microscopy (TEM). The average lattice constant and other important parameters of the microstructure such as the mean crystallite size, the dislocation density and the edge/screw character of dislocations were determined by XLPA. The elastic anisotropy factor required for XLPA procedure was determined by nanoindentation. XLPA shows that the crystallite size decreased while the dislocation density increased with strain during compression, and their values reached about 39 nm and 15 × 10{sup 14} m{sup −2}, respectively, at a plastic strain of ~ 20%. It was revealed that with increasing strain the dislocation character became more screw. This can be explained by the reduced mobility of screw dislocations compared to edge dislocations in bcc structures. These observations are in line with TEM investigations. The development of dislocation density during compression was related to the yield strength evolution. - Highlights: • Ti{sub 20}Zr{sub 20}Hf{sub 20}Nb{sub 20}Ta{sub 20} high entropy alloy was processed by arc-melting. • The mechanical was evaluated by RT compression test. • The microstructure evolution was studied by XLPA and TEM. • With increasing strain the dislocation character became more screw. • The yield strength was related to the development of the dislocation density.

  2. Preparation and characterization of Ce{sub 0.95}Zr{sub 0.05}O{sub 2} nanopowders obtained by sol-gel and template methods

    Energy Technology Data Exchange (ETDEWEB)

    Isasi, J., E-mail: isasi@quim.ucm.es [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Perez, M. [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Castillo, J.F. [Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Aldama, I.; Arevalo, P.; Carbajo, M.C. [Departamento de Quimica Inorganica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain)

    2012-09-14

    Ce{sub 0.95}Zr{sub 0.05}O{sub 2} nanopowders have been prepared by a standard Pechini-type sol-gel process and by using polymethyl methacrylate (PMMA) colloidal crystals as template. The effects of these different synthesis routes, on the structure and microstructural features of the nanopowders, were evaluated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area measurements. For both preparation routes, the XRD analysis has shown that a cubic fluorite structure is formed with a crystallite size of {approx}45-50 nm. The SEM images indicate that the powder obtained by the sol-gel Pechini-type process, is constituted by aggregated nanoparticles with relatively uniform shape and size, whereas the powder synthesized as inverse opal exhibits the formation of macropores with a mean size of {approx}130 nm. The specific surface areas of the powder samples obtained by the Pechini-type sol-gel and inverse opal methods are {approx}56 m{sup 2} g{sup -1} and {approx}90 m{sup 2} g{sup -1} respectively. Additionally, the thermoluminescence (TL) signal of the synthetized samples has been measured in order to examine its potential application in the field of dosimetry of ionizing radiations. -- Highlights: Black-Right-Pointing-Pointer Ce{sub 0.95}Zr{sub 0.05}O{sub 2} nanopowders synthesized by sol-gel and template methods. Black-Right-Pointing-Pointer Influence of the synthesis method on structural and microstructural features. Black-Right-Pointing-Pointer Analysis of the thermoluminescence response. Black-Right-Pointing-Pointer Study of application on dosimetry field.

  3. Reuse of cement-solidified municipal incinerator fly ash in cement mortars: physico-mechanical and leaching characteristics.

    Science.gov (United States)

    Cinquepalmi, Maria Anna; Mangialardi, Teresa; Panei, Liliana; Paolini, Antonio Evangelista; Piga, Luigi

    2008-03-01

    The reuse of cement-solidified Municipal Solid Waste Incinerator (MSWI) fly ash (solidified/stabilised (S/S) product) as an artificial aggregate in Portland cement mortars was investigated. The S/S product consisted of a mixture of 48 wt.% washed MSWI fly ash, 20 wt.% Portland cement and 32 wt.% water, aged for 365 days at 20 degrees C and 100% RH. Cement mortars (water/cement weight ratio=0.62) were made with Portland cement, S/S product and natural sand at three replacement levels of sand with S/S product (0%, 10% and 50% by mass). After 28 days of curing at 20 degrees C and 100% RH, the mortar specimens were characterised for their physico-mechanical (porosity, compressive strength) and leaching behaviour. No retardation in strength development, relatively high compressive strengths (up to 36 N/mm2) and low leaching rates of heavy metals (Cr, Cu, Pb and Zn) were always recorded. The leaching data from sequential leach tests on monolithic specimens were successfully elaborated with a pseudo-diffusional model including a chemical retardation factor related to the partial dissolution of contaminant.

  4. Directionally Solidified NiAl-Based Alloys Studied for Improved Elevated-Temperature Strength and Room-Temperature Fracture Toughness

    Science.gov (United States)

    Whittenberger, J. Daniel; Raj, Sai V.; Locci, Ivan E.; Salem, Jonathan A.

    2000-01-01

    Efforts are underway to replace superalloys used in the hot sections of gas turbine engines with materials possessing better mechanical and physical properties. Alloys based on the intermetallic NiAl have demonstrated potential; however, they generally suffer from low fracture resistance (toughness) at room temperature and from poor strength at elevated temperatures. Directional solidification of NiAl alloyed with both Cr and Mo has yielded materials with useful toughness and elevated-temperature strength values. The intermetallic alloy NiAl has been proposed as an advanced material to extend the maximum operational temperature of gas turbine engines by several hundred degrees centigrade. This intermetallic alloy displays a lower density (approximately 30-percent less) and a higher thermal conductivity (4 to 8 times greater) than conventional superalloys as well as good high-temperature oxidation resistance. Unfortunately, unalloyed NiAl has poor elevated temperature strength (approximately 50 MPa at 1027 C) and low room-temperature fracture toughness (about 5 MPa). Directionally solidified NiAl eutectic alloys are known to possess a combination of high elevated-temperature strength and good room-temperature fracture toughness. Research has demonstrated that a NiAl matrix containing a uniform distribution of very thin Cr plates alloyed with Mo possessed both increased fracture toughness and elevated-temperature creep strength. Although attractive properties were obtained, these alloys were formed at low growth rates (greater than 19 mm/hr), which are considered to be economically unviable. Hence, an investigation was warranted of the strength and toughness behavior of NiAl-(Cr,Mo) directionally solidified at faster growth rates. If the mechanical properties did not deteriorate with increased growth rates, directional solidification could offer an economical means to produce NiAl-based alloys commercially for gas turbine engines. An investigation at the NASA Glenn

  5. Flow-induced morphological instabilities due to temporally-modulated stagnation-point flow. [in single crystals growth by directionally-solidifying interface

    Science.gov (United States)

    Merchant, G. J.; Davis, S. H.

    1989-01-01

    The influence of periodically-modulated planar stagnation-point flow on the morphological stability of a directionally-solidifying interface is presently considered with a view to the effect of unsteady nonparallel flows on single-crystal growth. The modeling of the system assumes that the viscous boundary layer thickness is much greater than that of the solute boundary layer, and that the modulation frequency is much smaller than the strength of plane stagnation-point flow. The solidifying interface is either stabilized or destabilized depending on the ratio of the period of modulation to the solute-diffusion time.

  6. Microstructural development of rapid solidification in Al-Si powder

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Feng [Iowa State Univ., Ames, IA (United States)

    1995-09-26

    The microstructure and the gradient of microstructure that forms in rapidly solidificated powder were investigated for different sized particles. High pressure gas atomization solidification process has been used to produce a series of Al-Si alloys powders between 0.2 μm to 150 μm diameter at the eutectic composition (12.6 wt pct Si). This processing technique provides powders of different sizes which solidify under different conditions (i.e. interface velocity and interface undercooling), and thus give different microstructures inside the powders. The large size powder shows dendritic and eutectic microstructures. As the powder size becomes smaller, the predominant morphology changes from eutectic to dendritic to cellular. Microstructures were quantitatively characterized by using optical microscope and SEM techniques. The variation in eutectic spacing within the powders were measured and compared with the theoretical model to obtain interface undercooling, and growth rate during the solidification of a given droplet. Also, nucleation temperature, which controls microstructures in rapidly solidified fine powders, was estimated. A microstructural map which correlates the microstructure with particle size and processing parameters is developed.

  7. 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.

  8. 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

  9. Effect of a weak transverse magnetic field on the morphology and orientation of directionally solidified Al-Ni alloys

    Science.gov (United States)

    Li, Hanxiao; Fautrelle, Yves; Hou, Long; Du, Dafan; Zhang, Yikun; Ren, Zhongming; Lu, Xionggang; Moreau, Rene; Li, Xi

    2016-02-01

    The influence of a weak transverse magnetic field on the morphology and orientation of Al3Ni dendrites in directionally solidified Al-12 wt% Ni alloys was investigated. The experimental results indicated that the magnetic field caused segregation. It was also found that the application of a magnetic field decreased the primary dendrite spacing. By means of electronic backscatter diffraction (EBSD) analysis, the orientation of the Al3Ni dendrite was studied. In the case of no magnetic field, the crystal direction of the Al3Ni crystal was oriented along the solidification direction. When a transverse magnetic field was applied, the crystal direction rotated to the magnetic field direction, whereas the crystal direction remained oriented along the solidification direction. The above experimental results are discussed in the context of thermoelectric magnetic convection (TEMC) and crystal anisotropy.

  10. Influence of Growth Rate on Microstructural Length Scales in Directionally Solidified NiAl-Mo Hypo-Eutectic Alloy

    Science.gov (United States)

    Zhang, Jianfei; Ma, Xuewei; Ren, Huiping; Chen, Lin; Jin, Zili; Li, Zhenliang; Shen, Jun

    2016-01-01

    In this article, the Ni-46.1Al-7.8Mo (at.%) alloy was directionally solidified at different growth rates ranging from 15 μm/s to 1000 μm/s under a constant temperature gradient (334 K/cm). The dependence of microstructural length scales on the growth rate was investigated. The results show that, with the growth rate increasing, the primary dendritic arm spacings (PDAS) and secondary dendritic arm spacings (SDAS) decreased. There exists a large distribution range in PDAS under directional solidification conditions at a constant temperature gradient. The average PDAS and SDAS as a function of growth rate can be given as λ1 = 848.8967 V-0.4509 and λ2 = 64.2196 V-0.4140, respectively. In addition, a comparison of our results with the current theoretical models and previous experimental results has also been made.

  11. Effect of Sr content on porosity formation in directionally solidified Al-12.3wt.%Si alloy

    Directory of Open Access Journals (Sweden)

    Liao Hengcheng

    2014-09-01

    Full Text Available The influence of Sr addition on pore formation in directionally solidified Al-12.3wt.% alloy was investigated using X-ray detection, optical microscope, and SEM-EDX. Results indicate that addition of Sr significantly increases the number density and volume fraction of porosity. The considerable rise in volume fraction of porosity is attributed to the remarkable increase in the numbers of pores formed. It is found that Sr solute in liquid Al-Si alloy can diffuse into the oxide inclusions to form loose oxide aggregations which have more activity as the nucleation sites for porosity. Adding more Sr considerably increases the numbers of active nucleation sites. There is an obvious fluctuation of pore number density during steady state solidification, which is believed to be related to a fluctuation of local hydrogen supersaturation induced by the competition of pore nucleation and growth for hydrogen solute supplement.

  12. Numerical simulation of non-dendritic structure formation in Mg-Al alloy solidified with ultrasonic field.

    Science.gov (United States)

    Feng, Xiaohui; Zhao, Fuze; Jia, Hongmin; Li, Yingju; Yang, Yuansheng

    2018-01-01

    The formation of non-dendritic structure of Mg alloy solidified with ultrasonic treatment was investigated by numerical simulation and experiment. The models of nucleation and crystal growth involved the effects of ultrasonic cavitation and acoustic streaming were built. Based on the models, the grain refinement and the microstructure change from dendrite to non-dendritic structure of a Mg-Al alloy were numerically simulated by cellular automata method. The simulation and experimental results indicated that the ultrasonic cavitation strongly contributes to the grain refinement by improving nucleation, while the acoustic streaming is mainly responsible for the formation of non-dendritic structure. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Solidifying agent and processing of blood used for the larval diet affect screwworm (Diptera: Calliphoridae) life-history parameters.

    Science.gov (United States)

    Chaudhury, M F; Skoda, S R; Sagel, A

    2011-06-01

    Spray-dried whole bovine blood and a sodium polyacrylate polymer gel as a bulking and solidifying agent are among the constituents of the current larval diet for mass rearing screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae). Locally available, inexpensive dietary materials could reduce rearing cost and address an uncertain commercial supply of spray-dried blood. We compared efficacy of diet prepared from fresh bovine blood after decoagulation with sodium citrate or ethylenediaminetetraacetic acid (EDTA) or after mechanical defibrination, with the diet containing spray-dried blood using either gel or cellulose fiber as the bulking and solidifying agent. Several life-history parameters were compared among insects reared on each of the blood and bulking agent diets combination. Diets containing citrated blood yielded the lightest larval and pupal weights and fewest pupae. EDTA-treated blood with the gel also caused reductions. EDTA-treated blood with fiber yielded screwworms that were heavier and more numerous than those from the diet with citrated blood but lighter than those from the control diet using spray-dried blood. A reduction in percentage of adults emerging from pupae occurred from diets with both bulking agents using citrated blood and the diet using EDTA mixed with the gel bulking agent. As a group, the cellulose-fiber diets performed better than the gel diets. Larval diet did not affect adult longevity, weight of the eggs deposited by the females that emerged or subsequent egg hatch. Parameter measurements of insects from both defibrinated blood diets were similar to those from the spray-dried blood diets, indicating that fresh, defibrinated bovine blood can successfully replace the dry blood in the screwworm rearing medium.

  14. Advanced powder metallurgy aluminum alloys via rapid solidification technology

    Science.gov (United States)

    Ray, R.

    1984-01-01

    Aluminum alloys containing 10 to 11.5 wt. pct. of iron and 1.5 to 3 wt. pct. of chromium using the technique of rapid solidification powder metallurgy were studied. Alloys were prepared as thin ribbons (.002 inch thick) rapidly solidified at uniform rate of 10(6) C/second by the melt spinning process. The melt spun ribbons were pulverized into powders (-60 to 400 mesh) by a rotating hammer mill. The powders were consolidated by hot extrusion at a high reduction ratio of 50:1. The powder extrusion temperature was varied to determine the range of desirable processing conditions necessary to yield useful properties. Powders and consolidated alloys were characterized by SEM and optical metallography. The consolidated alloys were evaluated for (1) thermal stability, (2) tensile properties in the range, room temperature to 450 F, and (3) notch toughness in the range, room temperature to 450 F.

  15. Rapid Prototyping

    Science.gov (United States)

    1999-01-01

    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  16. 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

  17. Time exponent suppression of growth of the Zr–Sn diffusion layers between amorphous Zr{sub 55}Cu{sub 30}Al{sub 10}Ni{sub 5} and Sn

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Kan [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Lin, Tiesong, E-mail: hitjoining@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); He, Peng [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Sun, Jianfei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-10-15

    The growth kinetics of the diffusion layer between molten Sn and Zr{sub 55}Cu{sub 30}Al{sub 10}Ni{sub 5} bulk metallic glass (BMG) substrate were examined by isothermal aging at the temperature range between 513 and 633 K with 30 K temperature interval. The aged samples were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The growth of the diffusion layer is mainly controlled by a diffusion-controlled mechanism over the temperature range at stage I, and the value of the time exponent is approximately 1/2 by fitting the experiment data. As well as there is unusual stage II, whose time exponent of the growth is suppressed to 1/3. Based on phenomenological description, it could deduced that phase transition such like nucleation and coalescence occur in vicinity of the interface of diffusion layer at the late stage of clusters growth processes similar to Ostwald ripening. - Highlights: • Linear fitting of all experiment data of the thickness derivate the time exponent n be suppressed from 0.52 to 0.36. • There is the value of the time exponent following two stages by fitting the data segmentations. • The value of the time exponent is 1/2 at stage I, and 1/3 at stage II. • Phase transition such like nucleation, coalescence occur in vicinity of the interface of diffusion layer at stage II.

  18. Fabrication of amorphous Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} thin films by ion beam sputtering and their corrosion behavior in SBF for bio implants

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, B., E-mail: bsmanian@ceceri.res.in [CSIR – Central Electrochemical Research Institute, Karaikudi 630 006 (India); Yugeswaran, S.; Kobayashi, Akira [Joining and Welding Research Institute, Osaka University, Osaka 567-0047 (Japan); Jayachandran, M. [CSIR – Central Electrochemical Research Institute, Karaikudi 630 006 (India)

    2013-09-25

    Highlights: •The deposited alloys were shown to have amorphous structure. •Coated specimen had higher corrosion resistance in SBF. •Coatings were non-cytotoxic in nature. -- Abstract: The growth of multi component amorphous Zr{sub 48}Cu{sub 36}Al{sub 8}Ag{sub 8} thin film metallic glasses (TFMGs) using single target ion beam sputtering has been systematically investigated. The as prepared sputtering target was crystalline in nature. The presence of the constituent elements was identified from EPMA and AES analysis. An atomically disordered structure was observed by micro X-ray diffraction, electron diffraction and high resolution transmission electron microscopy. Glassy films with atomically smooth surfaces of the order of 0.4 nm with higher nanohardness of 9.33 GPa and Young’s modulus of 117 GPa compared to their crystalline substrate was observed from nanoindentation analysis. The study of in vitro corrosion of these coatings on implantable 316L stainless steel substrate in simulated body fluid (SBF) indicated that the as sputtered specimen had higher corrosion resistance without any localized pitting.

  19. Systematic studies of the fundamental chemistry of pyrochlore oxides. An{sub 2}Zr{sub 2}O{sub 7} [An=Pu, Am, Cm, Bk and Cf

    Energy Technology Data Exchange (ETDEWEB)

    Haire, R.G.; Assefa, Z. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Raison, P.E. [Commissariat a l' Energie Atomique, CEA-Cadarache DRN/DEC/SPUA/LACA (France)

    2002-11-01

    Our efforts to pursue the fundamental science of actinide pyrochlore oxides, An{sub 2}Zr{sub 2}O{sub 7}, (An=plutonium through californium), are presented. We have addressed their structural and chemical behavior via X-ray diffraction, Raman spectroscopy and by considering the pseudo-oxidation potentials of the actinides. The structure, fundamental chemistry, ionic radii and the electronic configuration of the specific actinide involved in these oxide systems all have a significant impact on their science. We are also exploring a calculational approach based on valence-bond relationships to assess the position of the oxygen atoms located at the general crystallographic position. The oxygen position is important regarding the chemical behavior and thermal stability of these materials. Also considered is the structural stability of the materials regarding self-irradiation, and with some compounds, their resistance towards oxidation. These aspects will be discussed using a systematic evaluation of the five-actinide systems together with comparable lanthanide systems studied. (author)

  20. 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.

  1. 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.

  2. TRLFS of Eu{sup 3+} and Cm{sup 3+} doped La{sub 2}Zr{sub 2}O{sub 7}: A comparison of defect fluorite to pyrochlore structures

    Energy Technology Data Exchange (ETDEWEB)

    Holliday, Kiel, E-mail: holliday7@llnl.gov [Karlsruhe Institut für Technologie, Institut für Nukleare Entsorgung, P.O. Box 3640, D-76021 Karlsruhe (Germany); Lawrence Livermore National Lab, 7000 East Ave., Livermore, CA 94550 (United States); Finkeldei, Sarah; Neumeier, Stefan [Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Walther, Clemens [Karlsruhe Institut für Technologie, Institut für Nukleare Entsorgung, P.O. Box 3640, D-76021 Karlsruhe (Germany); Leibniz Universität Hannover, Institut für Radioökologie und Strahlenschutz, D-30419 Hannover (Germany); Bosbach, Dirk [Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Forschungszentrum Jülich GmbH, D-52425 Jülich (Germany); Stumpf, Thorsten [Karlsruhe Institut für Technologie, Institut für Nukleare Entsorgung, P.O. Box 3640, D-76021 Karlsruhe (Germany); Karlsruhe Institut für Technologie, Institut für Anorganische Chemie, D-76131 Karlsruhe (Germany)

    2013-02-15

    Time-resolved laser fluorescence spectroscopy (TRLFS) was used to probe the local environment of Eu{sup 3+} and Cm{sup 3+} doped into La{sub 2}Zr{sub 2}O{sub 7} in both the defect fluorite and pyrochlore structures. It is evident that each structure has a dominant environment for the trivalent dopant ion. This makes it possible to characterize the fluorescence emission spectrum and lifetime for each Eu{sup 3+} and Cm{sup 3+} species. This data can be used for a relative quantification of the Eu{sup 3+} or Cm{sup 3+} in each local environment. This technique has application to verifying single phase material and probing radiation damage, and has been shown to be more sensitive than the current evaluation method of X-ray diffraction. The defect fluorite structure has a poorly defined site due to random oxygen vacancies and a short fluorescence lifetime, while the pyrochlore structure has a well defined emission and long fluorescence lifetime. The Cm{sup 3+} fluorescence from the pyrochlore structure was found to have a greater bathochromic shift (red shift) and larger ground state splitting of the {sup 8}S{sub 7/2} than previously reported in any system.

  3. Lead-free Ba{sub 0.8}Ca{sub 0.2}(Zr{sub x}Ti{sub 1−x})O{sub 3} ceramics with large electrocaloric effect

    Energy Technology Data Exchange (ETDEWEB)

    Asbani, B. [LPMC, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cédex (France); LMCN, F.S.T.G. Université Cadi Ayyad, BP 549 Marrakech (Morocco); Dellis, J.-L.; Lahmar, A.; Gagou, Y.; El Marssi, M., E-mail: mimoun.elmarssi@u-picardie.fr [LPMC, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cédex (France); Courty, M.; Djellab, K. [LRCS, UMR7314, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens Cédex (France); Amjoud, M.; Mezzane, D. [LMCN, F.S.T.G. Université Cadi Ayyad, BP 549 Marrakech (Morocco); Kutnjak, Z. [Jozef Stefan Institute, Jamova cesta 39, 1000 Ljubljana (Slovenia)

    2015-01-26

    The electrocaloric effect was investigated in lead-free Zr doped Ba{sub 0.8}Ca{sub 0.2}(Zr{sub x}Ti{sub 1−x})O{sub 3} (BCTZ) ceramics synthesized by a conventional sintering process. Room-temperature x-ray diffraction analysis showed that the tetragonal structure is obtained in BCTZ for x ≤ 0.08 and a pseudo cubic phase for x > 0.08. The dielectric spectroscopy and calorimetry revealed that the Curie temperature decreases as a consequence of Zr doping and that the BCTZ exhibits a first order ferroelectric phase transition. The electrocaloric effect was determined by the calculation of the electrocaloric change of temperature (ΔT) using the Maxwell relation based on the P–E hysteresis loops measured at different temperatures. A large electrocaloric responsivity ΔT/ΔE = 0.34 × 10{sup −6 }Km/V was found for x = 0.04, which significantly exceeds of values found so far in other lead-free electrocaloric materials.

  4. 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.

  5. 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.

  6. Microstructure evolution of Zr{sub 65}Al{sub 7.5}Cu{sub 12.5}Ni{sub 10}Ag{sub 5} bulk metallic glass due to rolling and its influence on the thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.J., E-mail: yanzhijie74@sohu.com [School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024 (China); Yan, J.; Hu, Y.; Hao, W.X. [School of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024 (China)

    2012-02-05

    X-ray diffraction (XRD), differential scanning calorimetry (DSC) and high-resolution transmission electron microscopy (HRTEM) are employed to investigate the microstructure evolution of Zr{sub 65}Al{sub 7.5}Cu{sub 12.5}Ni{sub 10}Ag{sub 5} bulk metallic glass subjected to rolling at room temperature. The strain rates are controlled to be 10{sup -4}-10{sup -3} s{sup -1}. The results show that the plastic deformation during rolling behaves as an inhomogeneous mode with the characteristic of shear bands, which results in the two-state characteristic of atomic movement from competition between the ordering and disordering processes. The icosahedron-like clusters precipitate in the transition regions between the shear bands and the amorphous matrix, and they tend to aggregate into nano-sized orders. The results of DSC indicate that the onset precipitation temperature of I-phase during heating of the metallic glass obviously decreases due to rolling. However, the time window for the completion of amorphous-to-icosahedral phase transformation is evidently lengthened. The microstructure evolution during rolling and its influence on the thermal stability are discussed.

  7. The enhancing performance of (Ba{sub 0.85}Ca{sub 0.15}Ti{sub 0.90}Zr{sub 0.10})O{sub 3} ceramics by tuning anatase–rutile phase structure

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Xiaolian, E-mail: chaoxl@snnu.edu.cn [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an, 710062, Shaanxi (China); Wang, Juanjuan [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an710048, Shaanxi (China); Wang, Zhongming; Zhang, Ting [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an, 710062, Shaanxi (China); Yang, Zupei, E-mail: yangzp@snnu.edu.cn [Key Laboratory for Macromolecular Science of Shaanxi Province, Shaanxi Engineering Lab for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an, 710062, Shaanxi (China); Li, Guangzhao [School of Materials Science and Engineering, Xi’an University of Technology, Xi’an710048, Shaanxi (China)

    2016-04-15

    Graphical abstract: Titanium dioxide (TiO{sub 2}) with different phase structure had interesting influence on the crystal structure, microstructure, the sintering temperature and electrical properties. - Highlights: • BCZT ceramics were prepared using either anatase or rutile structures as Ti source. • Orthorhombic and tetragonal mixture structure was exhibited by adjusting Ti source. • The optimal properties were observed in BCZT ceramics with rutile titanium dioxide. - Abstract: To research effect of raw materials TiO{sub 2} with the phase structures on the crystal structure, microstructure and electrical properties of lead-free (Ba{sub 0.85}Ca{sub 0.15})(Ti{sub 0.90}Zr{sub 0.10})O{sub 3} (BCZT) ceramics, BCZT ceramics using either anatase or rutile as Ti source were synthesized by solid-state reaction. Titanium dioxide (TiO{sub 2}) with anatase/rutile phase structures had interesting influence on the crystal structure, microstructure and the sintering temperature by the X-ray diffraction and SEM, which also played an important role in improved electrical properties. The BCZT ceramics with rutile titanium dioxide demonstrated optimal piezoelectric and dielectric properties: d{sub 33} = 590 pC/N, k{sub p} = 0.46, ε{sub r} = 2810, tanδ = 0.014 and T{sub c} = 91 °C, which was obviously superior to BCZT ceramics with anatase titanium dioxide.

  8. Characterization of the Ni-45wt% Ti shape memory alloy rapidly solidified; Caracterizacao da liga Ni-45wt%Ti com efeito de memoria de forma solidificadas rapidamente

    Energy Technology Data Exchange (ETDEWEB)

    Anselmo, G.C.S.; Castro, W.B. de; Araujo, C.J. de, E-mail: walman@dem.ufcg.edu.b [Universidade Federal de Campina Grande (UAEM/UFCG), PB (Brazil). Unidade Academica de Engenharia Mecanica

    2010-07-01

    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)

  9. A novel extraction method for β-carotene and other carotenoids in fruit juices using air-assisted, low-density solvent-based liquid-liquid microextraction and solidified floating organic droplets.

    Science.gov (United States)

    Sricharoen, Phitchan; Limchoowong, Nunticha; Techawongstien, Suchila; Chanthai, Saksit

    2016-07-15

    Green extraction using air-assisted, low-density solvent-based liquid-liquid microextraction and solidified floating organic droplets (AA-LDS-LLME-SFOD) prior to spectrophotometry was successfully applied for quantitation of carotenoids in fruit juices. Under optimal conditions, β-carotene could be quantified with a linear response up to a concentration of 60 μg mL(-1). The procedure was performed in a microcentrifuge tube with 40 μL of 1-dodecanol as the extraction solvent and a 1.0 mL juice sample containing 8% NaCl under seven extraction cycles of air pumping by syringe. This method was validated based on linearity (0.2-30 μg mL(-1), R(2) 0.998), limit of detection (0.04 μg mL(-1)) and limit of quantification (0.13 μg mL(-1)). The precision, expressed as the relative standard deviation (RSD) of the calibration curve slope (n=12), for inter-day and intra-day analysis was 4.85% and 7.92%, respectively. Recovery of β-carotene was in the range of 93.6-101.5%. The newly proposed method is simple, rapid and environmentally friendly, particularly as a useful screening test for food analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Detachment of secondary dendrite arm in a directionally solidified Sn-Ni peritectic alloy under deceleration growth condition

    Science.gov (United States)

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

    2016-06-01

    In order to better understand the detachment mechanism of secondary dendrite arm during peritectic solidification, the detachment of secondary dendrite arm from the primary dendrite arms in directionally solidified Sn-36at.%Ni peritectic alloys is investigated at different deceleration rates. Extensive detachment of secondary dendrite arms from primary stem is observed below peritectic reaction temperature TP. And an analytical model is established to characterize the detachment process in terms of the secondary dendrite arm spacing λ2, the root radius of detached arms and the specific surface area (SV) of dendrites. It is found that the detachment mechanism is caused by not only curvature difference between the tips and roots of secondary branches, but also that between the thicker secondary branches and the thinner ones. Besides, this detachment process is significantly accelerated by the temperature gradient zone melting (TGZM) effect during peritectic solidification. It is demonstrated that the reaction constant (f) which is used to characterize the kinetics of peritectic reaction is crucial for the determination of the detachment process. The value of f not only changes with growth rate but also with solidification time at a given deceleration rate. In conclusion, these findings help the better understanding of the detachment mechanism.

  11. Determination of molybdenum in plants by vortex-assisted emulsification solidified floating organic drop microextraction and flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Oviedo, Jenny A.; Fialho, Lucimar L.; Nóbrega, Joaquim A., E-mail: djan@terra.com.br

    2013-08-01

    A fast and sensitive procedure for extraction and preconcentration of molybdenum in plant samples based on solidified floating organic drop microextraction combined with flame atomic absorption spectrometry and discrete nebulization was developed. 8-Hydroxyquinoline (8-HQ) was used as complexing agent. The experimental conditions established were: 0.5% m v{sup −1} of 8-HQ, 60 μL of 1-undecanol as the extractant phase, 2 min vortex extraction time, centrifugation for 2 min at 2000 rpm, 10 min into an ice bath and discrete nebulization by introducing 200 μL of solution. The calibration curve was linear from 0.02 to 4.0 mg L{sup −1} with a limit of detection of 4.9 μg L{sup −1} and an enhancement factor of 67. The relative standard deviations for ten replicate measurements of 0.05 and 1.0 mg L{sup −1} Mo were 6.0 and 14.5%, respectively. The developed procedure was applied for determining molybdenum in corn samples and accuracy was proved using certified reference materials. - Highlights: ► Molybdenum was determined in plants by flame AAS. ► Flame AAS sensitivity was improved using microextraction and discrete nebulization. ► The developed procedure can be easily implemented in routine analysis. ► Green chemistry principles are followed.

  12. Modeling the growth of Byssochlamys fulva and Neosartorya fischeri on solidified apple juice by measuring colony diameter and ergosterol content.

    Science.gov (United States)

    Tremarin, Andréia; Longhi, Daniel Angelo; Salomão, Beatriz de Cassia Martins; Aragão, Gláucia Maria Falcão

    2015-01-16

    Byssochlamys fulva and Neosartorya fischeri are heat-resistant fungi which are a concern to food industries (e.g. apple juice industry) since their growth represents significant economic liabilities. Although the most common method used to assess fungal growth in solid substrates is by measuring the colony's diameter, it is difficult to apply this method to food substrates. Alternatively, ergosterol contents have been used to quantify fungal contamination in some types of food. The current study aimed at modeling the growth of the heat-resistant fungi B. fulva and N. fischeri by measuring the colony diameter and ergosterol content, fitting the Baranyi and Roberts model to the results, and finally establishing a correlation between the parameters of the two analytical methods. Whereas the colony diameter was measured daily, the quantification of ergosterol was performed when the colonies reached diameters of 30, 60, 90, 120 and 150 mm. Results showed that B. fulva and N. fischeri were able to grow successfully on solidified apple juice at 10, 15, 20, 25 and 30 °C, and the Baranyi and Roberts model showed good ability to describe growth data. The correlation curves between the parameters of colony diameter and ergosterol content were obtained with satisfactory statistical indexes. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Surface NH2-rich nanoparticles: Solidifying ionic-liquid electrolytes and improving the performance of dye-sensitized solar cells

    Science.gov (United States)

    Fang, Yanyan; Ma, Pin; Fu, Nianqing; Zhou, Xiaowen; Fang, Shibi; Lin, Yuan

    2017-12-01

    The surface properties of nanoparticles have a significant influence on the properties of the gel electrolytes. Herein, the surface NH2-rich nanoparticle (A-SiO2), with a tightening network, is synthesized by silanizing SiO2 nanoparticles with pre-polymerized aminopropyltriethoxysilane, which is further employed to prepare ionic-liquid gel electrolytes for dye-sensitized solar cells. The addition of a small amount of A-SiO2 can effectively solidify the ionic-liquid, whereas a large number of NH2 groups on the SiO2 surface leads to a large negative shift of the TiO2 conduction band edge, and can react with I3- in the form of a Lewis complex, resulting in an increase in the concentration of I- and a decrease in the concentration of I3- in the electrolyte. In addition, the ionic-liquid gel electrolyte possesses thixotropic behavior, which allows it to easily penetrate into the inner part of the TiO2 mesoporous film. As a result, large improvements of the photovoltage from 695 mV to 785 mV and of the photocurrent from 13.3 mA cm-2 to 14.9 mA cm-2 are achieved. This leads to significant enhancement of the power conversion efficiency, from 6.2% to 8.1%, for the cell with A-SiO2 compared to that of the pristine ionic-liquid electrolyte.

  14. 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.

  15. Effects of Growth Rates and Compositions on Dendrite Arm Spacings in Directionally Solidified Al-Zn Alloys

    Science.gov (United States)

    Acer, Emine; Çadırlı, Emin; Erol, Harun; Kaya, Hasan; Gündüz, Mehmet

    2017-12-01

    Dendritic spacing can affect microsegregation profiles and also the formation of secondary phases within interdendritic regions, which influences the mechanical properties of cast structures. To understand dendritic spacings, it is important to understand the effects of growth rate and composition on primary dendrite arm spacing ( λ 1) and secondary dendrite arm spacing ( λ 2). In this study, aluminum alloys with concentrations of (1, 3, and 5 wt pct) Zn were directionally solidified upwards using a Bridgman-type directional solidification apparatus under a constant temperature gradient (10.3 K/mm), resulting in a wide range of growth rates (8.3-165.0 μm/s). Microstructural parameters, λ 1 and λ 2 were measured and expressed as functions of growth rate and composition using a linear regression analysis method. The values of λ 1 and λ 2 decreased with increasing growth rates. However, the values of λ 1 increased with increasing concentration of Zn in the Al-Zn alloy, but the values of λ 2 decreased systematically with an increased Zn concentration. In addition, a transition from a cellular to a dendritic structure was observed at a relatively low growth rate (16.5 μm/s) in this study of binary alloys. The experimental results were compared with predictive theoretical models as well as experimental works for dendritic spacing.

  16. High Rate of N2 Fixation by East Siberian Cryophilic Soil Bacteria as Determined by Measuring Acetylene Reduction in Nitrogen-Poor Medium Solidified with Gellan Gum▿ †

    Science.gov (United States)

    Hara, Shintaro; Hashidoko, Yasuyuki; Desyatkin, Roman V.; Hatano, Ryusuke; Tahara, Satoshi

    2009-01-01

    For evaluating N2 fixation of diazotrophic bacteria, nitrogen-poor liquid media supplemented with at least 0.5% sugar and 0.2% agar are widely used for acetylene reduction assays. In such a soft gel medium, however, many N2-fixing soil bacteria generally show only trace acetylene reduction activity. Here, we report that use of a N2 fixation medium solidified with gellan gum instead of agar promoted growth of some gellan-preferring soil bacteria. In a soft gel medium solidified with 0.3% gellan gum under appropriate culture conditions, bacterial microbiota from boreal forest bed soils and some free-living N2-fixing soil bacteria isolated from the microbiota exhibited 10- to 200-fold-higher acetylene reduction than those cultured in 0.2% agar medium. To determine the N2 fixation-activating mechanism of gellan gum medium, qualitative differences in the colony-forming bacterial components from tested soil microbiota were investigated in plate cultures solidified with either agar or gellan gum for use with modified Winogradsky's medium. On 1.5% agar plates, apparently cryophilic bacterial microbiota showed strictly distinguishable microbiota according to the depth of soil in samples from an eastern Siberian Taiga forest bed. Some pure cultures of proteobacteria, such as Pseudomonas fluorescens and Burkholderia xenovorans, showed remarkable acetylene reduction. On plates solidified with 1.0% gellan gum, some soil bacteria, including Luteibacter sp., Janthinobacterium sp., Paenibacillus sp., and Arthrobacter sp., uniquely grew that had not grown in the presence of the same inoculants on agar plates. In contrast, Pseudomonas spp. and Burkholderia spp. were apparent only as minor colonies on the gellan gum plates. Moreover, only gellan gum plates allowed some bacteria, particularly those isolated from the shallow organic soil layer, to actively swarm. In consequence, gellan gum is a useful gel matrix to bring out growth potential capabilities of many soil diazotrophs and

  17. High rate of N2 fixation by East Siberian cryophilic soil bacteria as determined by measuring acetylene reduction in nitrogen-poor medium solidified with gellan gum.

    Science.gov (United States)

    Hara, Shintaro; Hashidoko, Yasuyuki; Desyatkin, Roman V; Hatano, Ryusuke; Tahara, Satoshi

    2009-05-01

    For evaluating N(2) fixation of diazotrophic bacteria, nitrogen-poor liquid media supplemented with at least 0.5% sugar and 0.2% agar are widely used for acetylene reduction assays. In such a soft gel medium, however, many N(2)-fixing soil bacteria generally show only trace acetylene reduction activity. Here, we report that use of a N(2) fixation medium solidified with gellan gum instead of agar promoted growth of some gellan-preferring soil bacteria. In a soft gel medium solidified with 0.3% gellan gum under appropriate culture conditions, bacterial microbiota from boreal forest bed soils and some free-living N(2)-fixing soil bacteria isolated from the microbiota exhibited 10- to 200-fold-higher acetylene reduction than those cultured in 0.2% agar medium. To determine the N(2) fixation-activating mechanism of gellan gum medium, qualitative differences in the colony-forming bacterial components from tested soil microbiota were investigated in plate cultures solidified with either agar or gellan gum for use with modified Winogradsky's medium. On 1.5% agar plates, apparently cryophilic bacterial microbiota showed strictly distinguishable microbiota according to the depth of soil in samples from an eastern Siberian Taiga forest bed. Some pure cultures of proteobacteria, such as Pseudomonas fluorescens and Burkholderia xenovorans, showed remarkable acetylene reduction. On plates solidified with 1.0% gellan gum, some soil bacteria, including Luteibacter sp., Janthinobacterium sp., Paenibacillus sp., and Arthrobacter sp., uniquely grew that had not grown in the presence of the same inoculants on agar plates. In contrast, Pseudomonas spp. and Burkholderia spp. were apparent only as minor colonies on the gellan gum plates. Moreover, only gellan gum plates allowed some bacteria, particularly those isolated from the shallow organic soil layer, to actively swarm. In consequence, gellan gum is a useful gel matrix to bring out growth potential capabilities of many soil

  18. The effect of thermal cycling on the structure and properties of a Co, Cr, Ni-TaC directionally solidified eutectic composite

    Science.gov (United States)

    Dunlevey, F. M.; Wallace, J. F.

    1973-01-01

    The effect of thermal cycling on the structure and properties of a cobalt, chromium, nickel, tantalum carbide directionally solidified eutectic composite is reported. It was determined that the stress rupture properties of the alloy were decreased by the thermal cycling. The loss in stress rupture properties varied with the number of cycles with the loss in properties after about 200 cycles being relatively high. The formation of serrations and the resulting changes in the mechanical properties of the material are discussed.

  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. 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.

  1. 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)

  2. Microstructure refinement and hardening of Ag–20 wt.%Cu alloy by rapid solidification

    Energy Technology Data Exchange (ETDEWEB)

    Lussana, Danilo, E-mail: danilo.lussana@unito.it [Dipartimento di Chimica and NIS, Università di Torino, Torino (Italy); Castellero, Alberto [Dipartimento di Chimica and NIS, Università di Torino, Torino (Italy); Vedani, Maurizio [Dipartimento di Meccanica, Politecnico di Milano, Milano (Italy); Ripamonti, Dario; Angella, Giuliano [Istituto IENI-CNR, Unità territoriale di Milano, Milano (Italy); Baricco, Marcello [Dipartimento di Chimica and NIS, Università di Torino, Torino (Italy)

    2014-12-05

    Highlights: • Ag80–Cu20 alloy were rapidly solidified by planar flow casting technique. • A significant refinement of the eutectic microstructure has been obtained. • A refinement of the primary silver-rich phase has been achieved with high cooling rate. • The hardness increases up to the 150% of the value of an annealed sample. - Abstract: Ag–20 wt.%Cu (wt%) hypoeutectic alloy has been rapidly solidified by means of planar flow casting technique. Two fcc solid solutions have been identified by X-ray diffraction. Microstructures have been observed by electron microscopy. A refinement of the eutectic microstructure, as well as of the Ag-rich primary phase, has been observed for high quenching rates, leading to a hardness value up to 235 Vickers. The lattice parameter and phase fraction of the Ag-rich solid solution increase as a function of quenching rates (i.e. wheel speed). The solidification processes occurring during rapid quenching have been described on the basis of thermodynamic and kinetic arguments.

  3. Structural changes in helium implanted Zr{sub 0.8}Y{sub 0.2}O{sub 1.9} single crystals characterized by atomic force microscopy and EXAFS spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kuri, G. [LWV, NES, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)], E-mail: goutam.kuri@psi.ch; Gavillet, D. [LWV, NES, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Doebeli, M. [Ion Beam Physics, Paul Scherrer Institute and ETH Zurich, CH-8093 Zurich (Switzerland); Novikov, D. [HASYLAB at Deutsches Elektronen-Synchrotron DESY, D-22603 Hamburg (Germany)

    2008-04-15

    The present work is devoted to investigate the local atomic environment (of Zr, Y and O) as well as surface modifications associated with excess helium in the cubic phase of (1 0 0)-oriented Zr{sub 0.8}Y{sub 0.2}O{sub 1.9} single crystal substrates. Commercially available oxide crystals have been implanted at various fluences in the range 0.15-2.0 x 10{sup 16} He-atoms/cm{sup 2} using a 2.74 MeV He{sup +} ion beam passing through a 8.0 {mu}m Al foil. The microstructure and surface morphology of the irradiated surface are examined using atomic force microscopy (AFM). The local atomic environments of Zr, Y and O in the implanted layer are studied using synchrotron radiation and by extended X-ray absorption fine structure (EXAFS) measured at glancing angles to probe the implanted layer. From AFM studies it was observed that the surface roughness increases as fluence increases and above a critical fluence stage, small blister-like structures originating from helium bubbles are scattered on the irradiated surface. The radial distribution functions (RDFs), derived from EXAFS data at the Zr K-edge, have been found to evolve continuously as a function of ion fluence describing the atomic scale structural modifications in YSZ by helium implantation. From the pristine data, long range order (beyond the first- and second-shell) is apparent in the RDF spectrum. It shows several nearest neighbour peaks at about 2.1, 3.6, 4.3 and 5.4 A. In the implanted specimens, all these peaks are greatly reduced in magnitude and their average positions are changed, typical of damaged material. A simple model taking into account only the existence of lattice vacancies has been used for the interpretation of measured EXAFS spectra.

  4. 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.

  5. Effect of an alkaline environment on the engineering behavior of cement-stabilized/solidified Zn-contaminated soils.

    Science.gov (United States)

    Liu, Jingjing; Zha, Fusheng; Deng, Yongfeng; Cui, Kerui; Zhang, Xueqin

    2017-10-12

    Although the stabilization/solidification method has been widely used for remediation of heavy metal-contaminated soils in recent decades, the engineering behavior and mobility of heavy metal ions under alkaline groundwater conditions are still unclear. Therefore, the unconfined compressive strength test (UCS) combined with toxicity characteristic leaching procedure (TCLP) and general acid neutralization capacity (GANC) was used to investigate the effects of alkalinity (using NaOH to simulate alkalinity in the environment) on the mechanical and leaching characteristics of cement-solidified/stabilized (S/S) Zn-contaminated soils. Moreover, the microstructure was analyzed using the scanning electron microscope (SEM) technology. The results indicated that alkaline environment could accelerate the UCS development compared with specimens without soaking in NaOH solution,, regardless of whether the specimens contained Zn2+ or not. And the UCS varied obviously attributed to the variations of both NaOH concentration and soaking time. Except for the specimens soaked for 90 days, the leached Zn2+ concentrations were higher than that of without soaking. However, the leachability of Zn2+ in all the stabilized specimens is in the regulatory level. ANC results indicated that the Zn2+ leaching behavior can be divided into three stages related to the initial leachate pH. Moreover, SEM results proved that the alkaline environment could actually facilitate the cement hydration process. The results proved in the present paper could be useful in treating the heavy metal-contaminated soils involved in the solidification/stabilization technology under alkaline environment.

  6. Structural, dielectric and magnetic studies of (x) Mg{sub 0.2}Cu{sub 0.3}Zn{sub 0.5}Fe{sub 2}O{sub 4} + (1-x) Ba{sub 0.8}Zr{sub 0.2}TiO{sub 3} magnetoelectric composites

    Energy Technology Data Exchange (ETDEWEB)

    Khader, S. Abdul, E-mail: khadersku@gmail.com; Sankarappa, T., E-mail: sankarappa@rediffmail.com [Department of Physics, Gulbarga University, Gulbarga-585106, Karnataka (India); Giridharan, N. V. [Department of Physics, National Institute of Technology, Tiruchirapalli-620015 (India); Chaudhuri, Arka [Department of Applied Science, Haldia Institute of Technology, Haldia-721657 (India)

    2016-05-06

    The Magneto-electric composites (x) Mg{sub 0.2}Cu{sub 0.3}Zn{sub 0.5}Fe{sub 2}O{sub 4} + (1-x) Ba{sub 0.8}Zr{sub 0.2}TiO{sub 3} (x=15%,30%,45%) were synthesized by sintering mixtures of highly ferroelectric Ba{sub 0.8}Zr{sub 0.2}TiO{sub 3} (BZT) and highly magneto-strictive component Mg{sub 0.2}Cu{sub 0.3}Zn{sub 0.5}Fe{sub 2}O{sub 4} (MCZF). The presences of two phases in magneto-electric composites were probed by X-ray diffraction (XRD) studies. The peaks observed in the XRD spectrum indicated spinel cubic structure for MCZF ferrite and tetragonal perovskite structure for BZT and, both spinel and pervoskite structures for synthesized composites. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM). Frequency dependent dielectric properties of synthesized composites were measured from 100 Hz to 1 MHz at RT using HIOKI LCR HI-TESTER. The dielectric dispersion is observed at lower frequencies for the synthesized ME composites. The magnetic properties of synthesized composites were analyzed using a Vibrating Sample Magnetometer (VSM). It is observed that the values of saturation magnetization increases along with the ferrite content.

  7. Stabilization/solidification of a porous waste by an hydraulic binder. Effects of grain size on the quality of the solidified product. Industrial test; Stabilisation/solidification d`un dechet poreux par un liant hydraulique influence de la granulometrie sur la qualite du produit solidifie, test industriel

    Energy Technology Data Exchange (ETDEWEB)

    Eyraud, P.; Teniere, C. [Groupement de Recherches de Lacq, 64 (France)

    1997-12-31

    The solidification of a porous and highly reactive waste (a catalyst that has been used for sulfuric acid) by the mean of a hydraulic binder, has been studied. Three different grain size distributions have been tested in order to determine if grinding is required before stabilization/solidification. The solidified waste is then evaluated through the SRETIE protocol. Site tests allowed for the optimization of an industrial scale implementation

  8. Improved textured La{sub 2}Zr{sub 2}O{sub 7} buffer on La{sub 3}TaO{sub 7} seed for all-MOD Buffer/YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Parans Paranthaman, M. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States)], E-mail: paranthamanm@ornl.gov; Bhuiyan, M.S.; Sathyamurthy, S. [Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6100 (United States); Heatherly, L.; Cantoni, C.; Goyal, A. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6116 (United States)

    2008-09-15

    The overall purpose of this research is to develop a potentially low-cost, high throughput, high yield, manufacturing process for buffer deposition, and to gain a fundamental understanding of buffer layers required for an all metal-organic deposition (MOD) based chemical solution approach. This understanding is critical to the development of a reliable, robust, low-cost, long-length manufacturing process of 2G wires. The standard RABiTS architectures consists of a starting template of biaxially textured Ni-W (5 at.%) substrate with a seed layer of Y{sub 2}O{sub 3}, a barrier layer of YSZ, and a CeO{sub 2} cap. In this three-layer architecture, all the buffers are deposited using reactive sputtering. We have recently demonstrated that the barrier properties and the performance of MOD La{sub 2}Zr{sub 2}O{sub 7} (LZO) match that of sputtered YSZ layers. In this work, the texture of MOD LZO was also improved by inserting a sputtered Y{sub 2}O{sub 3} seed layer on which LZO grows without any degradation of texture. Significant improvement in the texture of sputtered Y{sub 2}O{sub 3} seeds on NiW substrates is usually observed which is then transferred to the LZO layer. A key challenge for an all-solution approach is to replace the sputtered seed layer with a possible MOD seed layer with improved texture and on which no degradation of LZO texture occurs. Very recently, we have grown MOD La{sub 3}TaO{sub 7} (LTO) seeds directly on biaxially textured Ni-W (3 at.%) with improved texture. In this study, we report a systematic investigation of the growth MOD LZO barrier layer on MOD LTO seeds. Preliminary results show that it is possible to grow MOD LZO with improved texture on MOD LTO seeds. This approach could be potentially used for future all MOD buffer/YBCO coated conductors.

  9. Rapid solidification of an Al-5Ni alloy processed by spray forming

    Directory of Open Access Journals (Sweden)

    Conrado Ramos Moreira Afonso

    2012-10-01

    Full Text Available Recently, intermetallic compounds have attracted much attention due to their potential technological applications as high-temperature materials. In particular the intermetallic compounds, associated with the Al-Ni binary system stand out as promising candidates for high-temperature materials for the use in harsh environments. It is expected that a bulk Al-Ni alloy may exceed the strength of many commercial materials. The great challenge in developing these alloys is to manipulate the solidification thermal parameters in order to obtain the desired microstructural features. One of the indicated routes to obtain very refined intermetallic phases dispersed in the microstructure is the spray forming process. The dendritic and eutectic growth dependences on cooling rate are already known for directionally solidified (DS hypoeutectic Al-Ni alloys. In the case of rapidly solidified (RS samples, extrapolations of such experimental laws are needed, which can be very helpful to estimate realistic values of high cooling rates imposed during the spray forming process. The present study aims to compare directionally solidified and spray-formed Al-5wt. (%Ni alloy samples with a view to providing a basis for understanding how to control solidification parameters and the as-cast microstructure. The Al-5.0wt. (%Ni alloy was shown to have a cellular morphology for the overspray powder size range examined (up to 500 µm. The mean cell spacing decreased from 5.0 to 1.1 µm with the decrease in the powder average diameter. It was found that the experimental cooling rates imposed during the atomization step of the overspray powder solidification varied from 10³ to 2.10(4 K/s. The DSC trace depicted a crystallization peak of an amorphous structure fraction in the smallest Al-5.0wt. (%Ni alloy powder size range (<32 µm estimating a 15 µm critical diameter of amorphous powder in the binary Al97.5Ni2.5 (at% alloy.

  10. Interconnection between microstructure and microhardness of directionally solidified binary Al-6wt.%Cu and multicomponent Al-6wt.%Cu-8wt.%Si alloys.

    Science.gov (United States)

    Vasconcelos, Angela J; Kikuchi, Rafael H; Barros, André S; Costa, Thiago A; Dias, Marcelino; Moreira, Antonio L; Silva, Adrina P; Rocha, Otávio L

    2016-05-31

    An experimental study has been carried out to evaluate the microstructural and microhardness evolution on the directionally solidified binary Al-Cu and multicomponent Al-Cu-Si alloys and the influence of Si alloying. For this purpose specimens of Al-6wt.%Cu and Al-6wt.%Cu-8wt.%Si alloys were prepared and directionally solidified under transient conditions of heat extraction. A water-cooled horizontal directional solidification device was applied. A comprehensive characterization is performed including experimental dendrite tip growth rates (VL) and cooling rates (TR) by measuring Vickers microhardness (HV), optical microscopy and scanning electron microscopy with microanalysis performed by energy dispersive spectrometry (SEM-EDS). The results show, for both studied alloys, the increasing of TR and VL reduced the primary dendrite arm spacing (l1) increasing the microhardness. Furthermore, the incorporation of Si in Al-6wt.%Cu alloy to form the Al-6wt.%Cu-8wt.%Si alloy influenced significantly the microstructure and consequently the microhardness but did not affect the primary dendritic growth law. An analysis on the formation of the columnar to equiaxed transition (CET) is also performed and the results show that the occurrence of CET is not sharp, i.e., the CET in both cases occurs in a zone rather than in a parallel plane to the chill wall, where both columnar and equiaxed grains are be able to exist.

  11. 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 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.

  12. Release of radionuclides and chelating agents from cement-solidified decontamination low-level radioactive waste collected from the Peach Bottom Atomic Power Station Unit 3

    Energy Technology Data Exchange (ETDEWEB)

    Akers, D.W.; Kraft, N.C.; Mandler, J.W. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1994-03-01

    As part of a study being performed for the Nuclear Regulatory Commission (NRC), small-scale waste-form specimens were collected during a low oxidation-state transition-metal ion (LOMI)-nitric permanganate (NP)-LOMI solidification performed in October 1989 at the Peach Bottom Atomic Power Station Unit 3. The purpose of this program was to evaluate the performance of cement-solidified decontamination waste to meet the low-level waste stability requirements defined in the NRC`s ``Technical Position on Waste Form,`` Revision 1. The samples were acquired and tested because little data have been obtained on the physical stability of actual cement-solidified decontamination ion-exchange resin waste forms and on the leachability of radionuclides and chelating agents from those waste forms. The Peach Bottom waste-form specimens were subjected to compressive strength, immersion, and leach testing in accordance with the NRC`s ``Technical Position on Waste Form,`` Revision 1. Results of this study indicate that the specimens withstood the compression tests (>500 psi) before and after immersion testing and leaching, and that the leachability indexes for all radionuclides, including {sup 14}C, {sup 99}{Tc}, and {sup 129}I, are well above the leachability index requirement of 6.0, required by the NRC`s ``Technical Position on Waste Form,`` Revision 1.

  13. Compression and immersion tests and leaching of radionuclides, stable metals, and chelating agents from cement-solidified decontamination waste collected from nuclear power stations

    Energy Technology Data Exchange (ETDEWEB)

    Akers, D.W.; Kraft, N.C.; Mandler, J.W. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1994-06-01

    A study was performed for the Nuclear Regulatory Commission (NRC) to evaluate structural stability and leachability of radionuclides, stable metals, and chelating agents from cement-solidified decontamination ion-exchange resin wastes collected from seven commercial boiling water reactors and one pressurized water reactor. The decontamination methods used at the reactors were the Can-Decon, AP/Citrox, Dow NS-1, and LOMI processes. Samples of untreated resin waste and solidified waste forms were subjected to immersion and compressive strength testing. Some waste-form samples were leach-tested using simulated groundwaters and simulated seawater for comparison with the deionized water tests that are normally performed to assess waste-form leachability. This report presents the results of these tests and assesses the effects of the various decontamination methods, waste form formulations, leachant chemical compositions, and pH of the leachant on the structural stability and leachability of the waste forms. Results indicate that releases from intact and degraded waste forms are similar and that the behavior of some radionuclides such as {sup 55}Fe, {sup 60}Co, and {sup 99}Tc were similar. In addition, the leachability indexes are greater than 6.0, which meets the requirement in the NRC`s ``Technical Position on Waste Form,`` Revision 1.

  14. Inactivation efficiency and mechanism of UV-TiO2photocatalysis against murine norovirus using a solidified agar matrix.

    Science.gov (United States)

    Park, Daseul; Shahbaz, Hafiz Muhammad; Kim, Sun-Hyoung; Lee, Mijin; Lee, Wooseong; Oh, Jong-Won; Lee, Dong-Un; Park, Jiyong

    2016-12-05

    Human norovirus (HuNoV) is the primary cause of viral gastroenteritis worldwide. Fresh blueberries are among high risk foods associated with norovirus related outbreaks. Therefore, it is important to assess intervention strategies to reduce the risk of foodborne illness. The disinfection efficiency of decontamination methods is difficult to evaluate for fruits and vegetables due to an inconsistent degree of contamination and irregular surface characteristics. The inactivation efficiency and mechanism of murine norovirus 1 (MNV-1, a surrogate for HuNoV) was studied on an experimentally prepared solidified agar matrix (SAM) to simulate blueberries using different wavelengths (A, B, C) of UV light both with and without TiO 2 photocatalysis (TP). MNV-1 was inoculated on exterior and interior of SAM and inactivation efficiencies of different treatments were investigated using a number of assays. Initial inoculum levels of MNV-1 on the SAM surface and interior were 5.2logPFU/mL. UVC with TiO 2 (UVC-TP) achieved the highest level of viral reduction for both externally inoculated and internalized MNV-1. Externally inoculated MNV-1 was reduced to non-detectable levels after UVC-TP treatment for 5min while there was still a 0.9 log viral titer after UVC alone. For internalized MNV-1, 3.2 log and 2.7 log reductions were obtained with UVC-TP and UVC alone treatments for 10min, respectively. The Weibull model was applied to describe the inactivation behavior of MNV-1, and the model showed a good fit to the data. An excellent correlation between the steady-state concentration of OH radicals ([OH] ss ) and viral inactivation was quantified using a para-chlorobenzoic acid (pCBA) probe compound, suggesting that OH radicals produced in the UV-TP reaction were the major species for MNV-1 inactivation. Transmission electron microscopy images showed that the structure of viral particles was completely disrupted with UVC-TP and UVC alone. SDS-PAGE analysis showed that the major capsid

  15. Effect of Growth Rate on Elevated Temperature Plastic Flow and Room Temperature Fracture Toughness of Directionally Solidified NiAl-31Cr-3Mo

    Science.gov (United States)

    Whittenberger, J. Daniel; Raj, S. V.; Locci, I. E.; Salem, J. A.

    1999-01-01

    The eutectic system Ni-33Al-31Cr-3Mo was directionally solidified at rates ranging from 7.6 to 508 mm/h. Samples were examined for microstructure and alloy chemistry, compression tested at 1200 and 1300 K, and subjected to room temperature fracture toughness measurements. Lamellar eutectic grains were formed at 12.7 mm/h; however cellular structures with a radial eutectic pattern developed at faster growth rates. Elevated temperature compression testing between 10(exp -4) to 10(exp -7)/s did not reveal an optimum growth condition, nor did any single growth condition result in a significant fracture toughness advantage. The mechanical behavior, taken together, suggests that Ni-33Al-31Cr-3Mo grown at rates from 25.4 to 254 mm/h will have nominally equivalent properties.

  16. Solidified Floating Organic Drop Microextraction for the Detection of Trace Amount of Lead in Various Samples by Electrothermal Atomic Absorption Spectrometry

    Directory of Open Access Journals (Sweden)

    Oya Aydın Urucu

    2017-01-01

    Full Text Available A novel method was developed for determination of trace amounts of lead in water and food samples. Solidified floating organic drop microextraction was used to preconcentrate the lead ion. After the analyte was complexed with 1-(2-pyridylazo-2-naphthol, undecanol and acetonitrile were added as extraction and dispersive solvent, respectively. Variables such as pH, volumes of extraction and dispersive solvents, and concentration of chelating agent were optimized. Under the optimum conditions, the detection limit of Pb (II was determined as 0.042 µg L−1 with an enrichment factor of 300. The relative standard deviation is <10%. Accuracy of the developed procedure was evaluated by the analysis of certified reference material of human hair (NCS DC 73347 and wastewater (SPS-WW2 with satisfactory results. The developed procedure was then successfully applied to biscuit and water samples for detection of Pb (II ions.

  17. Development of a Fluid-Particle Model in Simulating the Motion of External Solidified Crystals and the Evolution of Defect Bands in High-Pressure Die Casting

    Science.gov (United States)

    Bi, Cheng; Xiong, Shoumei; Li, Xiaobo; Guo, Zhipeng

    2016-04-01

    A numerical fluid-particle model was developed to simulate the motion of external solidified crystals (ESCs) in the melt during the filling process of high-pressure die casting (HPDC). Simulation results on a tensile bar casting with two types of ingates (semi-circle and circle) revealed that for a long time scale the ESCs tended to distribute in a ring pattern around the specimen center, whereas for a short time scale the ESC distribution changed constantly from the ring pattern to either the center pattern or the ring-center pattern. It was proposed that the defect bands would form at these areas where two solidification fronts met (where solidification shrinkage occurred), including one originating from the skin layer of the specimen and the other from the ESC region. Accordingly, three types of defect band patterns, which were commonly observed in HPDC experiment, could be successfully simulated and explained using this model.

  18. Experimental investigation of influence of acid rain on leaching and hydraulic characteristics of cement-based solidified/stabilized lead contaminated clay.

    Science.gov (United States)

    Du, Yan-Jun; Jiang, Ning-Jun; Shen, Shui-Long; Jin, Fei

    2012-07-30

    Remediation of contaminated lands in China urban areas is of great concern. Degradation of construction facilities caused by acid rain is a serious environmental pollution issue in China. This paper presents an investigation of the effects of acid rain on leaching and hydraulic properties of cement-based solidified/stabilized lead contaminated soil. Laboratory tests including infiltration test and soaking test are conducted. It is found that the soil hydraulic conductivity decreases with increase in the pore volume of flow of permeant liquids (acid rain and distilled water). The decreasing rate in the case of the acid rain is lower than that in the case of the distilled water. The soaking test results show that pH and the presence of sulfate ions of acid rain have considerable influence on the leached concentrations and leaching rate of calcium. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Microstructural Characterization of a Directionally-Solidified Ni-33 (at. %)Al-31Cr-3Mo Eutectic Alloy as a Function of Withdrawal Rate

    Science.gov (United States)

    Raj, S. V.; Locci, I. E.; Whittenberger, J. D.; Salem, J. A.

    2000-01-01

    The Ni-33 (at. %)Al-3lCr-3Mo eutectic alloy was directionally-solidified (DS) at different rates, V(sub I), varying between 2.5 to 508 mm/ h. Detailed qualitative and quantitative metallographic and chemical analyses were conducted on the directionally-solidified rods. The microstructures consisted of eutectic colonies with parallel lamellar NiAl/(Cr,Mo) plates for solidification rates at and below 12.7 mm/ h. Cellular eutectic microstructures were observed at higher solidification rates, where the plates exhibited a radial pattern. The microstructures were demonstrated to be fairly uniform throughout a 100 mm length of the DS zone by quantitative metallography. The average cell size, bar-d, decreased with increasing growth rate to a value of 125 microns at 508 mm/ h according to the relation bar-d (microns) approx. = 465 V(sup -0.22, sub I), where V(sub I) is in mm/ h. Both the average NiAl plate thickness, bar-Delta(sub NiAl), and the interlamellar spacing, bar-lambda, were observed to be constant for V(sub I) less than or = 50.8 mm/ h but decreased with increasing growth rate above this value as 0.93 bar-Delta(sub NiAl)(microns) = 61.2 V(sup -0.93, sub I) and bar-lambda (microns) = 47.7 V(sup -0.64, sub I), respectively. The present results are detailed on a microstructural map. Keywords Optical microscopy, microstructure, compounds intermetallic, directional solidification

  20. 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.

  1. Simultaneously fabrication of free and solidified N, S-doped graphene quantum dots via a facile solvent-free synthesis route for fluorescent detection.

    Science.gov (United States)

    Xia, Chang; Hai, Xin; Chen, Xu-Wei; Wang, Jian-Hua

    2017-06-01

    A facile one-step solvent-free synthesis approach is proposed for the simultaneous fabrication of free and solidified N, S-doped graphene quantum dots (N, S-GQDs) by using citric acid as precursor and L-cysteine as dopant. Graphene nucleus is firstly formed via the intermolecular dehydration of citric acid. N and S are then incorporated into the graphene structure by attacking the margin of graphene nucleus. The cross-linking among the graphene nucleus via the intermolecular condensation leads to the generation of free N, S-GQDs, while the intermolecular amidation between L-cysteine molecules and graphene nucleuses contributes to the solid-state fluorescence graphene quantum dots (SSF-GQDs). The free N, S-GQDs exhibit favorable photoluminescence behaviors such as high fluorescent quantum yield of 74.5%, stable photoluminescence within a wide range of pH and high tolerance to external ionic strength of up to 1.0molL-1 NaCl, making it excellent fluorescence probe for the sensitive detection of Fe3+ with a linear range of 0.01-3μM and a detection limit of 3.3nM. The solidification of GQDs prevents the aggregation of GQDs efficiently and offers the solidified N, S-GQDs yellow-green fluorescence, with a fluorescence quantum yield of 10.6%. This proposed protocol provides a novel avenue to fabricate diverse fluorescent graphene materials for different practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Ultra-fast in-situ X-ray studies of evolving columnar dendrites in solidifying steel weld pools

    OpenAIRE

    Mirihanage, W.U.; Di Michiel, M.; Mathiesen, R.H.

    2015-01-01

    High-brilliance polychromatic synchrotron radiation has been used to conduct in-situ studies of the solidification microstructure evolution during simulated welding. The welding simulations were realized by rapidly fusing ~ 5 mm spot in Fe-Cr-Ni steel. During the solid- liquid-solid phase transformations, a section of the weld pool was placed in an incident 50-150 keV polychromatic synchrotron X-ray beam, in a near-horizontal position at a very low inclination angle. Multiple high-resolution ...

  3. Rapid Prototyping Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The ARDEC Rapid Prototyping (RP) Laboratory was established in December 1992 to provide low cost RP capabilities to the ARDEC engineering community. The Stratasys,...

  4. Improved stress corrosion cracking resistance of a novel biodegradable EW62 magnesium alloy by rapid solidification, in simulated electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Hakimi, O.; Aghion, E. [Department of Materials Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Goldman, J., E-mail: jgoldman@mtu.edu [Biomedical Engineering Department, Michigan Technological University, Houghton, MI, 49931 (United States)

    2015-06-01

    The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg–6%Nd–2%Y–0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd{sub 2}O{sub 3} content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications. - Highlights: • Here we have evaluated the corrosion resistance of a novel Mg alloy (EW62). • Rapid solidification reduces the hydrogen gas evolution and hydrogen embrittlement. • Rapid solidification increases the stress corrosion cracking resistance of EW62. • Improvement is due to enrichment with supersaturated Nd in the external oxide film. • Rapidly solidified and extruded EW62 may serve as a biodegradable medical implant.

  5. On the Nonequilibrium Interface Kinetics of Rapid Coupled Eutectic Growth

    Science.gov (United States)

    Dong, H.; Chen, Y. Z.; Shan, G. B.; Zhang, Z. R.; Liu, F.

    2017-08-01

    Nonequilibrium interface kinetics (NEIK) is expected to play an important role in coupled growth of eutectic alloys, when solidification velocity is high and intermetallic compound or topologically complex phases form in the crystallized product. In order to quantitatively evaluate the effect of NEIK on the rapid coupled eutectic growth, in this work, two nonequilibrium interface kinetic effects, i.e., atom attachment and solute trapping at the solid-liquid interface, were incorporated into the analyses of the coupled eutectic growth under the rapid solidification condition. First, a coupled growth model incorporating the preceding two nonequilibrium kinetic effects was derived. On this basis, an expression of kinetic undercooling (∆ T k), which is used to characterize the NEIK, was defined. The calculations based on the as-derived couple growth model show good agreement with the reported experimental results achieved in rapidly solidified eutectic Al-Sm alloys consisting of a solid solution phase ( α-Al) and an intermetallic compound phase (Al11Sm3). In terms of the definition of ∆ T k defined in this work, the role of NEIK in the coupled growth of the Al-Sm eutectic system was analyzed. The results show that with increasing the coupled growth velocity, ∆ T k increases continuously, and its ratio to the total undercooling reaches 0.32 at the maximum growth velocity for coupled eutectic growth. Parametric analyses on two key alloy parameters that influence ∆ T k, i.e., interface kinetic parameter ( μ i ) and solute distribution coefficient ( k e ), indicate that both μ i and k e influence the NEIK significantly and the decrease of either these two parameters enhances the NEIK effect.

  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. Rapid Airplane Parametric Input Design (RAPID)

    Science.gov (United States)

    Smith, Robert E.

    1995-01-01

    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool

  8. Rapid shallow breathing

    Science.gov (United States)

    ... the smallest air passages of the lungs in children ( bronchiolitis ) Pneumonia or other lung infection Transient tachypnea of the newborn Anxiety and panic Other serious lung disease Home Care Rapid, shallow breathing should not be treated at home. It is ...

  9. Rapid Strep Test

    Science.gov (United States)

    ... worse than normal. Your first thoughts turn to strep throat. A rapid strep test in your doctor’s office ... your suspicions.Viruses cause most sore throats. However, strep throat is an infection caused by the Group A ...

  10. Rapid Solidification of AB{sub 5} Hydrogen Storage Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gulbrandsen-Dahl, Sverre

    2002-01-01

    thesis the changes of the crystal structure and the grain structure of La{sub 0.60}Ce{sub 0.29}Pr{sub 0.04}Nd{sub 0.07}Ni{sub 3.37}Co{sub 0.79}Mn{sub 0.25}Al{sub 0.7}= cooling rate during chill-block melt spinning are described. Totally, the material was rapidly solidified at 9 different cooling rates. The grain structure, crystallographic texture and the lattice parameters were studied by means of electron microscopy and powder X-ray diffraction. Additionally, the density of the rapidly solidified materials was measured by a gas pycnometer. All these properties were found to change with increasing cooling rate. The grain size decreased continuously with increasing cooling rate and was in the range of 1-5 {mu}m. The strength of the crystallographic texture first increased and then decreased with increasing cooling rate. Transmission electron microscopy studies revealed that the grains contained a large amount of crystallographic twins and that the solidification morphology changed from cellular to plane front at a cooling rate during solidification of approximately 6*10{sup 4} Ks{sup -1}. The unit cell volume and the density followed the same pattern with increasing cooling rate and decreased within each solidification morphology, but at the cooling rate from which the morphology changed, both these parameters suddenly increased. The identical variations in the unit cell volume and the density is explained by formation of excess lattice vacancies during rapid solidification. In Part IV of the thesis rapid solidification of the materials La{sub 0.60}Ce{sub 0.27}Pr{sub 0.04}Nd{sub 0.09}Ni{sub 4.76}Sn{sub 0.24} and LaNi{sub 4.76}Sn different cooling rates are described. The materials were analysed by means of electron microscopy and powder X-ray diffraction. The grain structures of both alloys were found to be in the nanometer range, and the grain sizes were almost invariant with increasing cooling rate. Furthermore, the lattice parameters of these materials were almost

  11. RAPID3? Aptly named!

    Science.gov (United States)

    Berthelot, J-M

    2014-01-01

    The RAPID3 score is the sum of three 0-10 patient self-report scores: pain, functional impairment on MDHAQ, and patient global estimate. It requires 5 seconds for scoring and can be used in all rheumatologic conditions, although it has mostly been used in rheumatoid arthritis where cutoffs for low disease activity (12/30) have been set. A RAPID3 score of ≤ 3/30 with 1 or 0 swollen joints (RAPID3 ≤ 3 + ≤ SJ1) provides remission criteria comparable to Boolean, SDAI, CDAI, and DAS28 remission criteria, in far less time than a formal joint count. RAPID3 performs as well as the DAS28 in separating active drugs from placebos in clinical trials. RAPID3 also predicts subsequent structural disease progression. RAPID3 can be determined at short intervals at home, allowing the determination of the area under the curve of disease activity between two visits and flare detection. However, RAPID3 should not be seen as a substitute for DAS28 and face to face visits in routine care. Monitoring patient status with only self-report information without a rheumatologist's advice (including joints and physical examination, and consideration of imaging and laboratory tests) may indeed be as undesirable for most patients than joint examination without a patient questionnaire. Conversely, combining the RAPID3 and the DAS28 may consist in faster or more sensitive confirmation that a medication is effective. Similarly, better enquiring of most important concerns of patients (pain, functional status and overall opinion on their disorder) should reinforces patients' confidence in their rheumatologist and treatments.

  12. Columnar-to-Equiaxed Transition and Equiaxed Grain Alignment in Directionally Solidified Ni3Al Alloy Under an Axial Magnetic Field

    Science.gov (United States)

    Liu, Huan; Xuan, Weidong; Xie, Xinliang; Li, Chuanjun; Wang, Jiang; Yu, Jianbo; Li, Xi; Zhong, Yunbo; Ren, Zhongming

    2017-09-01

    The effect of an axial magnetic field on the solidification structure in directionally solidified Ni-21.5Al-0.4Zr-0.1B (at. pct) alloy was investigated. The experimental results indicated that the application of a high magnetic field caused the deformation of dendrites and the occurrence of columnar-to-equiaxed transition (CET). The magnetic field tended to orient the 〈001〉 crystal direction of the equiaxed grains along the magnetic field direction. The bulk solidification experiment under a high magnetic field showed that the crystal exhibited magnetic crystalline anisotropy. Further, the thermoelectric (TE) magnetic force and TE magnetic convention were analyzed by three-dimensional (3-D) numerical simulations. The results showed that the maximum value of TE magnetic force localized in the vicinity of the secondary dendrite arm root, which should be responsible for the dendrite break and CET. Based on the high-temperature creep mechanism, a simple model was proposed to describe the magnetic field intensity needed for CET: B ≥ kG^{ - 1.5} R^{1.25} . The model is in good agreement with the experiment results. The experimental results should be attributed to the combined action of TE magnetic effects and the magnetic moment.

  13. Effects of Withdrawal Rate and Temperature Gradient on the Microstructure Evolution in Directionally Solidified NiAl-36Cr-6Mo Hypereutectic Alloy

    Science.gov (United States)

    Shang, Zhao; Shen, Jun; Zhang, Jian-Fei; Wang, Lei; Qin, Ling; Fu, Heng-Zhi

    2014-09-01

    The effects of withdrawal rate and temperature gradient on the microstructure and growth interface morphology in directionally solidified Ni-29Al-36Cr-6Mo(at.%) hypereutectic alloy were investigated. Under the temperature gradient of 250 K/cm, well-aligned eutectic microstructure with lamellar morphology was obtained at the withdrawal rate of 6 μm/s. When the withdrawal rate was 10 μm/s, the microstructure changed to Cr(Mo) dendrites + eutectic lamellae. With the increasing withdrawal rate, the interdendritic eutectic growth interface changed from planar to cellular, the number of primary Cr(Mo) dendrites became greater, and the microstructure was refined. When the temperature gradient increased to 600 K/cm, the coupled eutectic growth zone of NiAl-Cr(Mo) alloy was expanded; a well-aligned eutectic microstructure could be obtained at higher rate of 10 μm/s. Furthermore, the planar/cellular transition rate of the interdendritic eutectic growth interface increased. Even at the same withdrawal rate, the number of primary Cr(Mo) dendrites was less and the microstructure was finer under the temperature gradient of 600 K/cm.

  14. Novel solidified reverse micellar solution-based mucoadhesive nano lipid gels encapsulating miconazole nitrate-loaded nanoparticles for improved treatment of oropharyngeal candidiasis.

    Science.gov (United States)

    Kenechukwu, Franklin Chimaobi; Attama, Anthony Amaechi; Ibezim, Emmanuel Chinedum

    2017-09-01

    To develop and evaluate solidified-reverse-micellar-solution (SRMS)-based oromucosal nano lipid gels for improved localised delivery of miconazole nitrate (MN). Phospholipon ® 90G and Softisan ® 154 (3:7) were used to prepare SRMS by fusion. Solid lipid nanoparticles (SLNs, 0.25-1.0% w/w MN) formulated with the SRMS by high shear homogenisation were employed to prepare mucoadhesive nano lipid gels. Physicochemical characterisation, drug release in simulated salivary fluid (SSF) (pH 6.8) and anti-candidal activity were carried out. The SLNs were spherical nanoparticles, had mean size of 133.8 ± 6.4 to 393.2 ± 14.5 nm, low polydispersity indices, good encapsulation efficiency (EE) (51.96 ± 2.33-67.12 ± 1.65%) and drug loading (DL) (19.05 ± 2.44-24.93 ± 1.98%). The nano lipid gels were stable, spreadable, pseudoplastic viscoelastic mucoadhesive systems that exhibited better prolonged release and anti-candidal properties than marketed formulation (Daktarin ® oral gel) (p < 0.05). This study has shown that SRMS-based nano lipid gels could be employed to prolong localised oromucosal delivery of MN.

  15. Coupling Effects of Melt Treatment and Ultrasonic Treatment on Solidifying Microstructure and Mechanical Performance of Ti44Al6Nb1Cr Alloy

    Science.gov (United States)

    Deshuang, Zheng; Ruirun, Chen; Tengfei, Ma; Hongsheng, Ding; Yanqing, Su; Jingjie, Guo; Hengzhi, Fu

    2018-02-01

    The coupling effects of melt treatment and ultrasonic treatment on the solidifying microstructure and mechanical performance of Ti44Al6Nb1Cr alloy are investigated. During melt treatment, a low superheat degree is beneficial for microstructure refinement, with the lamellar colony size decreasing from 512 to 243 μm, while a low cooling rate leads to the microstructure coarsening as the lamellar colony size enlarges from 458 to 615 μm. After coupling with ultrasonic treatment, under moderate superheat degree and cooling rate, the original coarse lamellar colony size is significantly refined to 56 and 38 μm, the compressive strength is improved by 60.71 and 47.89 pct, and the compressive strain is enlarged by 80.19 and 112.33 pct, respectively. It is found that the ultrasonic refining efficiency is dominated by the melt temperature, and there is an optimum temperature range near the crystallization temperature: a too-high temperature leads to the remelting of crystal nuclei, impairing the refining efficiency, whereas a too-low temperature results in high viscosity, hindering the ultrasonic effects. Under ultrasonic treatment, the melt supercooling is increased, leading to an extended constitutional supercooling region, which will enlarge the crystal nucleation; the solute enrichment is enhanced, forming a quasi-steady state with a higher solution concentration gradient, which improves the crystal growth velocity.

  16. 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.

  17. 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...

  18. 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®.

  19. Determination of Cadmium by Electrothermal Atomic Absorption Spectrometry after its Separation and Preconcentration by Syringe to Syringe Dispersive Liquid Phase Microextraction-Solidified Floating Organic Drop

    Directory of Open Access Journals (Sweden)

    Mohammad Asadi

    2017-12-01

    Full Text Available The application of syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop was extended for the separation and preconcentration of trace amounts of cadmium ions from water and cereal samples. The extracted cadmium was quantified by electrothermal atomic absorption spectrometry. Factors affecting the complex formation as well as microextraction efficiency such as the concentration of dithizone as the chelating agent, sample pH, type and volume of the extractant, number of injections, ionic strength and sample volume were optimized. Under optimized conditions, the calibration curve was linear in the range of 1.0-14.0 ng L-1 with the coefficient of determination of 0.9994. The limit of detection and quantification were found to be 0.25 and 0.85 ng L-1, respectively. The inter-day and intra-day precision at two concentration levels (3.0 and 10.0 ng L-1 were in the range of 3.9-9.2%. The accuracy of the developed method was evaluated through recovery experiments and the analysis of certified reference material (SLRS-6.

  20. Speciation of antimony(III) and antimony(V) by electrothermal atomic absorption spectrometry after ultrasound-assisted emulsification of solidified floating organic drop microextraction.

    Science.gov (United States)

    Wen, Shengping; Zhu, Xiashi

    2013-10-15

    A simple, sensitive and efficient method of ultrasound-assisted emulsification of solidified floating organic drop microextraction (USE-SFODME) coupled to electrothermal atomic absorption spectrometry for the speciation of antimony at different oxidation state Sb(III)/Sb(V) in environmental samples was established. In this method, the hydrophobic complex of Sb(III) with sodium diethyldithiocarbamate (DDTC) is extracted by 1-undecanol at pH 9.0, while Sb(V) remains in aqueous phase. Sb(V) content can be calculated by subtracting Sb(III) from the total antimony after reducing Sb(V) to Sb(III) by l-cysteine. Various factors affecting USE-SFODME including pH, extraction solvent and its volume, concentration of DDTC, sonication time, and extraction temperature were investigated. Under the optimized conditions, the calibration curve was linear in the range from 0.05 to 10.0 ng mL(-1), with the limit of detection (3σ) 9.89 ng L(-1) for Sb(III). The relative standard deviation for Sb(III) was 4.5% (n=9, c=1.0 ng mL(-1)). This method was validated against the certified reference materials (GSB 07-1376-2001, GBW07441), and applied to the speciation of antimony in environmental samples (soil and water samples) with satisfactory results. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Inverse steptoes in Las Bombas volcano, as an evidence of explosive volcanism in a solidified lava flow field. Southern Mendoza-Argentina

    Science.gov (United States)

    Risso, Corina; Prezzi, Claudia; Orgeira, María Julia; Nullo, Francisco; Margonari, Liliana; Németh, Karoly

    2015-11-01

    Here we describe the unusual genesis of steptoes in Las Bombas volcano- Llancanelo Volcanic Field (LVF) (Pliocene - Quaternary), Mendoza, Argentina. Typically, a steptoe forms when a lava flow envelops a hill, creating a well-defined stratigraphic relationship between the older hill and the younger lava flow. In the Llancanelo Volcanic Field, we find steptoes formed with an apparent normal stratigraphic relationship but an inverse age-relationship. Eroded remnants of scoria cones occur in ;circular depressions; in the lava field. To express the inverse age-relationship between flow fields and depression-filled cones here we define this landforms as inverse steptoes. Magnetometric analysis supports this inverse age relationship, indicating reverse dipolar magnetic anomalies in the lava field and normal dipolar magnetization in the scoria cones (e.g. La Bombas). Negative Bouguer anomalies calculated for Las Bombas further support the interpretation that the scoria cones formed by secondary fracturing on already solidified basaltic lava flows. Advanced erosion and mass movements in the inner edge of the depressions created a perfectly excavated circular depression enhancing the ;crater-like; architecture of the preserved landforms. Given the unusual genesis of the steptoes in LVF, we prefer the term inverse steptoe for these landforms. The term steptoe is a geomorphological name that has genetic implications, indicating an older hill and a younger lava flow. Here the relationship is reversed.

  2. Leaching behavior and effectiveness of curing days (7& 28) of solidified/stabilized fly ash based geopolymer (multi-metal bearing sludge): experimental and modeling study.

    Science.gov (United States)

    Chaudhary, Rubina; Khaleb, Divya; Badur, Smita

    2012-04-01

    This paper presents the study of the immobilization of heavy metals like Pb, Fe, Mn, Cu and Zn by fly ash based geopolymers. The purpose of this study was to investigate the effectiveness of fly ash based geopolymeric solidification/stabilization technology. For S/S of waste, geopolymer as a binding agent was mixed with waste at different ratios. For initial waste characterization, contaminants concentration and some physical waste characterization such as dry density, bulk density, specific gravity, porosity, moisture holding capacity, and moisture content were determined. Waste and geopolymer mixture were cured for 7 and 28 days to study the effect of curing days on the solidified/ stabilized product. Diffusion leaching test was performed on the geopolymers containing industrial sludge to determine the leaching mechanism of binders to entrap the waste constituents within their matrix. Movement of the elements was identified with the help of leachability index. S/S through geopolymer was found to be effective in immobilizing toxic metals present in the sludge. Zn was 100% and other metals like Pb, Fe, Mn and Cu were in the range 80-99% immobilized. The order of fixation of metals was Zn >Cu > Fe > Mn > Pb.

  3. Influence of cooling rate on microstructure formation during rapid solidification of binary TiAl alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kenel, C., E-mail: Christoph.Kenel@empa.ch; Leinenbach, C.

    2015-07-15

    Highlights: • Rapid solidification studies with varying cooling rates were realized for Ti–Al. • Experiments were combined with finite element simulations of heat transfer. • The resulting microstructure of Ti–Al alloys is strongly dependent on the Al content. • The microstructure and phase transformation behavior can be predicted. • The method allows alloy development for processes involving rapid solidification. - Abstract: Titanium aluminides as structural intermetallics are possible candidates for a potential weight reduction and increased performance of high temperature components. A method for the characterization of the microstructure formation in rapidly solidified alloys was developed and applied for binary Ti–(44–48)Al (at.%). The results show a strong dependency of the microstructure on the Al content at cooling rates between 6 ⋅ 10{sup 2} and 1.5 ⋅ 10{sup 4} K s{sup −1}. The formation of α → α{sub 2} ordering, lamellar α{sub 2} + γ colonies and interdendritic TiAl γ-phase were observed, depending on the Al amount. Based on thermodynamic calculations the observed microstructure can be explained using the CALPHAD approach taking into account the non-equilibrium conditions. The presented method provides a useful tool for alloy development for processing techniques involving rapid solidification with varying cooling rates.

  4. Development of solid SEDDS, III: application of Acconon® C-50 and Gelucire® 50/13 as both solidifying and emulsifying agents for medium chain triglycerides

    Directory of Open Access Journals (Sweden)

    Nrupa Patel

    2012-06-01

    Full Text Available Solid self-emulsifying drug delivery systems (SEDDS for medium chain triglycerides (Captex® 355, ABITEC were developed using stearoyl polyoxyl glycerides (Acconon® C-50, ABITEC and Gelucire® 50/13, Gattefosse as both solidifying and emulsifying agents. Different mixtures of the lipid and each solidifying agent were heated to 65ºC until homogenously mixed clear liquids were formed. Probucol was dissolved as the model drug. The molten mass was then filled into hard gelatin capsules, which upon cooling to room temperature converted to a solid mass inside capsules. The triglyceride could be incorporated into the system to a concentration as high as 80% w/w, still maintaining the solid or semisolid consistency of the system. Powder XRD, DSC, microscopy (cross-polarization and confocal fluorescence techniques, dispersion test and particle size analysis of the solid systems with, and without, drug were conducted to characterize different formulations. The solidifying agents maintained their crystallinity in solid systems, while the lipids were interspersed in between crystalline regions. The drug remained solubilized in the lipid phase. The formulations dispersed almost completely in 2 hours with particle size of the dispersed lipid in the range of 250 to 500 nm when the lipid content in the formulation was up to 50% w/w. Thus, a novel method of developing solid formulations of liquid triglycerides by incorporating lipids in stearoyl polyoxyl glycerides has been developed.

  5. Rapid small lot manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, R.W.

    1998-05-09

    The direct connection of information, captured in forms such as CAD databases, to the factory floor is enabling a revolution in manufacturing. Rapid response to very dynamic market conditions is becoming the norm rather than the exception. In order to provide economical rapid fabrication of small numbers of variable products, one must design with manufacturing constraints in mind. In addition, flexible manufacturing systems must be programmed automatically to reduce the time for product change over in the factory and eliminate human errors. Sensor based machine control is needed to adapt idealized, model based machine programs to uncontrolled variables such as the condition of raw materials and fabrication tolerances.

  6. Rapid Cycling and Its Treatment

    Science.gov (United States)

    ... Announcements Public Service Announcements Partnering with DBSA Rapid Cycling and its Treatment What is bipolar disorder? Bipolar ... to Depression and Manic Depression . What is rapid cycling? Rapid cycling is defined as four or more ...

  7. Temperature-dependent stability of energy storage properties of Pb{sub 0.97}La{sub 0.02}(Zr{sub 0.58}Sn{sub 0.335}Ti{sub 0.085})O{sub 3} antiferroelectric ceramics for pulse power capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhen; Chen, Xuefeng; Peng, Wei; Xu, Chenhong; Dong, Xianlin; Cao, Fei; 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)

    2015-06-29

    The dielectric properties and electrical hysteresis behaviors of Pb{sub 0.97}La{sub 0.02}(Zr{sub 0.58}Sn{sub 0.335}Ti{sub 0.085})O{sub 3} antiferroelectric (AFE) ceramics were investigated in this work with an emphasis on energy storage properties. Three phase transition points can be detected as temperature increases. AFE and paraelectric phases are found to coexist from 100 °C to 170 °C. The room temperature recoverable energy density is 1.37 J/cm{sup 3} at 8.6 kV/mm. With increasing temperature (from 20 °C to 100 °C) and frequency (from 0.01 to 100 Hz) under 8.6 kV/mm, the variation of recoverable energy density was less than 15%, all higher than 1.2 J/cm{sup 3}. All the corresponding energy efficiencies were no less than 75%. The high energy density, high energy efficiency, and their weak dependence on temperature and frequency during a wide scope indicate that these antiferroelectric ceramics are quite promising to be used for pulse power capacitors applications.

  8. Hemispherical total emissivity and specific heat capacity of deeply undercooled Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10.0}Be{sub 22.5} melts

    Energy Technology Data Exchange (ETDEWEB)

    Busch, R.; Kim, Y.J.; Johnson, W.L. [W. M. Keck Laboratory of Engineering Materials, California Institute of Technology, Pasadena, California 91125 (United States); Rulison, A.J.; Rhim, W.K. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States); Isheim, D. [Institut fuer Metallphysik der Universitaet Goettingen, Hospitalstrasse 3-7, 37073 Goettingen (Germany)

    1995-06-05

    High-temperature high-vacuum electrostatic levitation (HTHVESL) and differential scanning calorimetry (DSC) were combined to determine the hemispherical total emissivity {epsilon}{sub {ital T}}, and the specific heat capacity {ital c}{sub {ital p}}, of the undercooled liquid and throughout the glass transition of the Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10.0}Be{sub 22.5} bulk metallic glass forming alloy. The ratio of {ital c}{sub {ital p}}/{epsilon}{sub {ital T}} as a function of undercooling was determining from radiative cooling curves measured in the HTHVESL. Using specific heat capacity data obtained by DSC investigations close to the glass transition and above the melting point, {epsilon}{sub {ital T}} and {ital c}{sub {ital p}} were separated and the specific heat capacity of the whole undercooled liquid region was determined. Furthermore, the hemispherical total emissivity of the liquid was found to be about 0.22 at 980 K. On undercooling the liquid, the emissivity decreases to approximately 0.18 at about 670 K, where the undercooled liquid starts to freeze to a glass. No significant changes of the emissivity are observed as the alloy undergoes the glass transition. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  9. 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.

  10. (abstract) Determination of the Specific Heat and Total Hemispherical Total Emissivity of the Highly Undercooled Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) Alloy

    Science.gov (United States)

    Busch, R.; Kim, Y. J.; Johnson, W. L.; Rulison, A. J.; Rhim, W. K.

    1995-01-01

    High temperature high vacuum electrostatic levitation was combined with DSC experiments to determine the specific heat C(sub p) of the undercooled Zr(sub 41.2)Ti(sub 13.8)Cu(sub 12.5)Ni(sub 10.0)Be(sub 22.5) liquid as a function of temperature. The containerless approach made it possible to undercool the melt to the glass transition temperature without inducing nucleation. Because the cooling process was purely radiative, noncontact temperature measurement techniques could be used to determine the specific heat to total hemispherical emissivity ratio, C(sub p)/epsilon(sub t), for the undercooled liquid region. Using C(sub p) values which were independently obtained by DSC, epsilon(sub t) could be determined. With knowledge of C(sub p) of the undercooled liquid it was possible to determine other thermodynamic properties such as Gibbs free energy and entropy as a function of undercooling.

  11. Rapid manufacturing for microfluidics

    CSIR Research Space (South Africa)

    Land, K

    2012-10-01

    Full Text Available . Microfluidics is at the forefront of developing solutions for drug discovery, diagnostics (from glucose tests to malaria and TB testing) and environmental diagnostics (E-coli monitoring of drinking water). In order to quickly implement new designs, a rapid...

  12. Rapid Prototyping in PVS

    Science.gov (United States)

    Munoz, Cesar A.; Butler, Ricky (Technical Monitor)

    2003-01-01

    PVSio is a conservative extension to the PVS prelude library that provides basic input/output capabilities to the PVS ground evaluator. It supports rapid prototyping in PVS by enhancing the specification language with built-in constructs for string manipulation, floating point arithmetic, and input/output operations.

  13. Rapid Prototyping Reconsidered

    Science.gov (United States)

    Desrosier, James

    2011-01-01

    Continuing educators need additional strategies for developing new programming that can both reduce the time to market and lower the cost of development. Rapid prototyping, a time-compression technique adapted from the high technology industry, represents one such strategy that merits renewed evaluation. Although in higher education rapid…

  14. Dendritic Arm Spacing Affecting Mechanical Properties and Wear Behavior of Al-Sn and Al-Si Alloys Directionally Solidified under Unsteady-State Conditions

    Science.gov (United States)

    Cruz, Kleber S.; Meza, Elisangela S.; Fernandes, Frederico A. P.; Quaresma, José M. V.; Casteletti, Luiz C.; Garcia, Amauri

    2010-04-01

    Alloys of Al-Sn and Al-Si are widely used in tribological applications such as cylinder liners and journal bearings. Studies of the influence of the as-cast microstructures of these alloys on the final mechanical properties and wear resistance can be very useful for planning solidification conditions in order to permit a desired level of final properties to be achieved. The aim of the present study was to contribute to a better understanding about the relationship between the scale of the dendritic network and the corresponding mechanical properties and wear behavior. The Al-Sn (15 and 20 wt pct Sn) and Al-Si (3 and 5 wt pct Si) alloys were directionally solidified under unsteady-state heat flow conditions in water-cooled molds in order to permit samples with a wide range of dendritic spacings to be obtained. These samples were subjected to tensile and wear tests, and experimental quantitative expressions correlating the ultimate tensile strength (UTS), yield tensile strength, elongation, and wear volume to the primary dendritic arm spacing (DAS) have been determined. The wear resistance was shown to be significantly affected by the scale of primary dendrite arm spacing. For Al-Si alloys, the refinement of the dendritic array improved the wear resistance, while for the Al-Sn alloys, an opposite effect was observed, i.e., the increase in primary dendrite arm spacing improved the wear resistance. The effect of inverse segregation, which is observed for Al-Sn alloys, on the wear resistance is also discussed.

  15. Alloy composition dependence of formation of porous Ni prepared by rapid solidification and chemical dealloying

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhen [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Zhang Zhonghua [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)], E-mail: zh_zhang@sdu.edu.cn; Jia Haoling [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China); Qu Yingjie [Shandong Labor Occupational Technology College, Jingshi Road 388, Jinan 250022 (China); Liu Guodong; Bian Xiufang [Key Laboratory of Liquid Structure and Heredity of Materials, Shandong University, Jingshi Road 73, Jinan 250061 (China)

    2009-03-20

    In this paper, the effect of alloy composition on the formation of porous Ni catalysts prepared by chemical dealloying of rapidly solidified Al-Ni alloys has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and N{sub 2} adsorption experiments. The experimental results show that rapid solidification and alloy composition have a significant effect on the phase constituent and microstructure of Al-Ni alloys. The melt spun Al-20 at.% Ni alloy consists of {alpha}-Al, NiAl{sub 3} and Ni{sub 2}Al{sub 3}, while the melt spun Al-25 and 31.5 at.% Ni alloys comprise NiAl{sub 3} and Ni{sub 2}Al{sub 3}. Moreover, the formation and microstructure of the porous Ni catalysts are dependent upon the composition of the melt spun Al-Ni alloys. The morphology and size of Ni particles in the Ni catalysts inherit from those of grains in the melt spun Al-Ni alloys. Rapid solidification can extend the alloy composition of Al-Ni alloys suitable for preparation of the Ni catalysts, and obviously accelerate the dealloying process of the Al-Ni alloys.

  16. Rapid manufacturing facilitated customisation

    OpenAIRE

    Tuck, Christopher John; Hague, Richard; Ruffo, Massimiliano; Ransley, Michelle; Adams, Paul Russell

    2008-01-01

    Abstract This paper describes the production of body-fitting customised seat profiles utilising the following digital methods: three dimensional laser scanning, reverse engineering and Rapid Manufacturing (RM). The seat profiles have been manufactured in order to influence the comfort characteristics of an existing ejector seat manufactured by Martin Baker Aircraft Ltd. The seat, known as Navy Aircrew Common Ejection Seat (NACES), was originally designed with a generic profile. ...

  17. Rapid Detection of Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    David Perlin

    2005-08-14

    Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development

  18. 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

  19. Tiber Personal Rapid Transit

    Directory of Open Access Journals (Sweden)

    Diego Carlo D'agostino

    2011-02-01

    Full Text Available The project “Tiber Personal Rapid Transit” have been presented by the author at the Rome City Vision Competition1 2010, an ideas competition, which challenges architects, engineers, designers, students and creatives individuals to develop visionary urban proposals with the intention of stimulating and supporting the contemporary city, in this case Rome. The Tiber PRT proposal tries to answer the competition questions with the definition of a provocative idea: a Personal Rapid transit System on the Tiber river banks. The project is located in the central section of the Tiber river and aims at the renewal of the river banks with the insertion of a Personal Rapid Transit infrastructure. The project area include the riverbank of Tiber from Rome Transtevere RFI station to Piazza del Popolo, an area where main touristic and leisure attractions are located. The intervention area is actually no used by the city users and residents and constitute itself a strong barrier in the heart of the historic city.

  20. Giant magnetoimpedance intrinsic impedance and voltage sensitivity of rapidly solidified Co{sub 66}Fe{sub 2}Cr{sub 4}Si{sub 13}B{sub 15} amorphous wire for highly sensitive sensors applications

    Energy Technology Data Exchange (ETDEWEB)

    Das, Tarun K.; Mandal, Sushil K. [CSIR - National Metallurgical Laboratory, NDE and Magnetic Materials Group, MST Division, Jamshedpur (India); Banerji, Pallab [Indian Institute of Technology, Kharagpur, Materials Science Centre, Kharagpur (India)

    2016-11-15

    We report a systematic study of the influence of wire length, L, dependence of giant magneto-impedance (GMI) sensitivity of Co{sub 66}Fe{sub 2}Cr{sub 4}Si{sub 13}B{sub 15} soft magnetic amorphous wire of diameter ∝ 100 μm developed by in-water quenching technique. The magnetization behaviour (hysteresis loops) of the wire with different length (L = 1, 2, 3, 5, 8 and 10 cm) has been evaluated by fuxmetric induction method. It was observed that the behaviour of the hysteresis loops change drastically with the wire length, being attributed to the existence of a critical length, L{sub C}, found to be around 3 cm. GMI measurements have been taken using automated GMI measurement system and the GMI sensitivities in terms of intrinsic impedance sensitivity (S{sub Ω/Am}{sup -1}) and voltage sensitivity (S{sub V/Am}{sup -1}) of the wire have been evaluated under optimal bias field and excitation current. It was found that the maximum (S{sub Ω/Am}{sup -1}){sub max} ∼ 0.63 Ω/kAm{sup -1}/cm and (S{sub V/Am}{sup -1}){sub max} ∼ 3.10 V/kAm{sup -1}/cm were achieved at a critical length L{sub C} ∝ 3 cm of the wire for an AC current of 5 mA and a frequency of 5 MHz. These findings provide crucial insights for optimization of the geometrical dimensions of magnetic sensing elements and important practical guidance for designing high sensitive GMI sensors. The relevant combinations of magnetic material parameters and operating conditions that optimize the sensitivity are highlighted. (orig.)

  1. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  2. Rapid prototype and test

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, D.L.; Hansche, B.D.

    1996-06-01

    In order to support advanced manufacturing, Sandia has acquired the capability to produce plastic prototypes using stereolithography. Currently, these prototypes are used mainly to verify part geometry and ``fit and form`` checks. This project investigates methods for rapidly testing these plastic prototypes, and inferring from prototype test data actual metal part performance and behavior. Performances examined include static load/stress response, and structural dynamic (modal) and vibration behavior. The integration of advanced non-contacting measurement techniques including scanning laser velocimetry, laser holography, and thermoelasticity into testing of these prototypes is described. Photoelastic properties of the epoxy prototypes to reveal full field stress/strain fields are also explored.

  3. Right-Rapid-Rough

    Science.gov (United States)

    Lawrence, Craig

    2003-01-01

    IDEO (pronounced 'eye-dee-oh') is an international design, engineering, and innovation firm that has developed thousands of products and services for clients across a wide range of industries. Its process and culture attracted the attention of academics, businesses, and journalists around the world, and are the subject of a bestselling book, The Art of Innovation by Tom Kelley. One of the keys to IDEO's success is its use of prototyping as a tool for rapid innovation. This story covers some of IDEO's projects, and gives reasons for why they were successful.

  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

    Electron Spin Resonance spectroscopy (ESR) was used to measure the mobility of the spin probe TEMPO in O/W-emulsions. This allowed determination of temperature-dependent microviscosity of the liquid fraction in lipid globules. Six hydrogenated palm kernel oil (HPKO) based emulsions containing...... 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...

  5. Rapid mineralocorticoid receptor trafficking.

    Science.gov (United States)

    Gekle, M; Bretschneider, M; Meinel, S; Ruhs, S; Grossmann, C

    2014-03-01

    The mineralocorticoid receptor (MR) is a ligand-dependent transcription factor that physiologically regulates water-electrolyte homeostasis and controls blood pressure. The MR can also elicit inflammatory and remodeling processes in the cardiovascular system and the kidneys, which require the presence of additional pathological factors like for example nitrosative stress. However, the underlying molecular mechanism(s) for pathophysiological MR effects remain(s) elusive. The inactive MR is located in the cytosol associated with chaperone molecules including HSP90. After ligand binding, the MR monomer rapidly translocates into the nucleus while still being associated to HSP90 and after dissociation from HSP90 binds to hormone-response-elements called glucocorticoid response elements (GREs) as a dimer. There are indications that rapid MR trafficking is modulated in the presence of high salt, oxidative or nitrosative stress, hypothetically by induction or posttranslational modifications. Additionally, glucocorticoids and the enzyme 11beta hydroxysteroid dehydrogenase may also influence MR activation. Because MR trafficking and its modulation by micro-milieu factors influence MR cellular localization, it is not only relevant for genomic but also for nongenomic MR effects. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Rapid response manufacturing (RRM)

    Energy Technology Data Exchange (ETDEWEB)

    Cain, W.D. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Waddell, W.L. [National Centers for Manufacturing Sciences, Ann Arbor, MI (United States)

    1997-02-18

    US industry is fighting to maintain its competitive edge in the global market place. Today markets fluctuate rapidly. Companies, to survive, have to be able to respond with quick-to-market, improved, high quality, cost efficient products. The way products are developed and brought to market can be improved and made more efficient through the proper incorporation of emerging technologies. The RRM project was established to leverage the expertise and resources of US private industries and federal agencies to develop, integrate, and deploy new technologies that meet critical needs for effective product realization. The RRM program addressed a needed change in the US Manufacturing infrastructure that will ensure US competitiveness in world market typified by mass customization. This project provided the effort needed to define, develop and establish a customizable infrastructure for rapid response product development design and manufacturing. A major project achievement was the development of a broad-based framework for automating and integrating the product and process design and manufacturing activities involved with machined parts. This was accomplished by coordinating and extending the application of feature-based product modeling, knowledge-based systems, integrated data management, and direct manufacturing technologies in a cooperative integrated computing environment. Key technological advancements include a product model that integrates product and process data in a consistent, minimally redundant manner, an advanced computer-aided engineering environment, knowledge-based software aids for design and process planning, and new production technologies to make products directly from design application software.

  7. 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.

  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. Phosphate Ca{sub 1/4}Sr{sub 1/4}Zr{sub 2}(PO{sub 4}){sub 3} of the NaZr{sub 2}(PO{sub 4}){sub 3} structure type: Synthesis of a dense ceramic material and its radiation testing

    Energy Technology Data Exchange (ETDEWEB)

    Orlova, A.I., E-mail: albina.orlova@inbox.ru [N.I. Lobachevsky State University of Nizhny Novgorod, Gagarina Ave. 23, 603950 Nizhny Novgorod (Russian Federation); Volgutov, V.Yu.; Mikhailov, D.A.; Bykov, D.M. [N.I. Lobachevsky State University of Nizhny Novgorod, Gagarina Ave. 23, 603950 Nizhny Novgorod (Russian Federation); Skuratov, V.A. [Joint Institute for Nuclear Research, Joliot-Curie St. 6, 141980 Dubna (Russian Federation); Chuvil’deev, V.N.; Nokhrin, A.V.; Boldin, M.S.; Sakharov, N.V. [Physico-Technical Research Institute of the State University of Nizhny Novgorod, Gagarina Ave. 23, b. 3, 603950 Nizhny Novgorod (Russian Federation)

    2014-03-15

    Highlights: •High density ceramics with NZP structure were prepared by Spark Plasma Sintering. •Ceramic materials were irradiated in cyclotron by Xe ions with fluences 6 × 10{sup 10} to 1 × 10{sup 13} ions/cm{sup 2}. •The conditions of transformation from metamict to crystalline state have been found. -- Abstract: The powder of phosphate Ca{sub 1/4}Sr{sub 1/4}Zr{sub 2}(PO{sub 4}){sub 3} was synthesized by sol–gel processes in the presence of citric acid and ethylene glycol. Ceramic samples were prepared from this powder by Spark Plasma Sintering (SPS), their relative densities were found to be 99.5 ± 0.3% after the isothermal treatment at 860 °S for 3 min. Sintered disc-shaped ceramic samples (d = 10 mm, h = 4 mm) were bombarded at 300 K by 167 MeV Xe{sup 26+} ions with fluences ranging from 6 ⋅ 10{sup 10} to 1 ⋅ 10{sup 13} ions/cm{sup 2}. It was found that exposure to the highest fluence (10{sup 13} ion/cm{sup 2}) led to a complete amorphization of the irradiated layer. The observed phase transition is ascribed to the formation of amorphous latent tracks via dense electronic excitations. Postradiation heat treatment revealed that the transformation from metamict to crystalline form took place after annealing at T = 200, 300, 400, 500, 600 and 800 °S and t = 3, 13, 11, 5, 17 and 15 h, respectively.

  10. 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.

  11. Rapid Refresh (RAP) [13 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  12. Rapid Refresh (RAP) [20 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Refresh (RAP) numerical weather model took the place of the Rapid Update Cycle (RUC) on May 1, 2012. Run by the National Centers for Environmental...

  13. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  14. Microstructure Formation and Resistivity Change in CuCr during Rapid Solidification

    Directory of Open Access Journals (Sweden)

    Ulla Hauf

    2017-11-01

    Full Text Available The formation of the surface-near microstructure after a current interruption of CuCr contact materials in a vacuum interrupter is characterized by a fast heating and subsequently rapid solidification process. In the present article, we reveal and analyse the formation of two distinct microstructural regions that result from the heat, which is generated and dissipated during interruption. In the topmost region, local and global texture, as well as the resulting microstructure, indicate that both Cu and Cr were melted during rapid heating and solidification whereas in the region underneath, only Cu was melted and elongated Cu-grains solidified with the <001>-direction perpendicularly aligned to the surface. By analysing the lattice parameter of the Cu solid solution, a supersaturation of the solid solution with about 2.25 at % Cr was found independent if Cu was melted solely or together with the Cr. The according reduction of electrical conductivity in the topmost region subsequent to current interruption and the resulting heat distribution are discussed based on these experimental results.

  15. Rapid solidification mechanism of highly undercooled ternary Cu40Sn45Sb15 alloy

    Science.gov (United States)

    Zhai, W.; Wang, B. J.; Lu, X. Y.; Wei, B.

    2015-10-01

    The rapid solidification of ternary Cu40Sn45Sb15 peri-eutectic type alloy was realized by glass fluxing and drop tube methods, and the corresponding maximum undercoolings are 185 K (0.22 T L) and 321 K (0.39 T L), respectively. The phase constitution of Cu40Sn45Sb15 alloy in these two rapid solidification experiments deviates from the two equilibrium phases (Sn + Cu6Sn5). In glass fluxing method, the structural morphology of Cu40Sn45Sb15 alloy is mainly characterized by a three-layer lamellar structure, which is comprised by an inner layer of long strips of primary ɛ(Cu3Sn) phase, an intermediate layer of η(Cu6Sn5) phase and an outer layer of β(SnSb) phase. As undercooling rises, this lamellar structure is remarkably refined. When small alloy droplets are containerlessly solidified during free fall in drop tube, the primary ɛ(Cu3Sn) phase grows by non-faceted mode into dendrites as droplet diameter decreases. Especially, solidification path alters in the smallest droplet with 50 μm diameter, in which η(Cu6Sn5) and Sn3Sb2 phases form directly from the metastable liquid phase by suppressing the primary ɛ phase formation and the following peri-eutectic transformation.

  16. Selective laser sintering: application of a rapid prototyping method in craniomaxillofacial reconstructive surgery.

    Science.gov (United States)

    Aung, S C; Tan, B K; Foo, C L; Lee, S T

    1999-09-01

    Advances in technology have benefited the medical world in many ways and a new generation of computed tomography (CT) scanners and three-dimensional (3-D) model making rapid prototyping systems (RPS) have taken craniofacial surgical planning and management to new heights. With the development of new rapid prototyping systems and the improvements in CT scan technology, such as the helical scanner, biomedical modelling has improved considerably and accurate 3-D models can now be fabricated to allow surgeons to visualise and physically handle a 3-D model on which simulation surgery can be performed. The principle behind this technology is to first acquire digital data (CT scan data) which is then imported to the RPS to fabricate fine layers or cuts of the model which are gradually built up to form the 3-D models. Either liquid resin or nylon powder or special paper may be used to make these models using the various RPS available today. Selective laser sintering (SLS), which employs a CO2 laser beam to solidify special nylon powder and build up the model in layers is described in this case report, where a 23-year old Chinese female with panfacial fracture and a skull defect benefited from SLS biomodelling in the preoperative workup.

  17. Building a rapid response team.

    Science.gov (United States)

    Halvorsen, Lisa; Garolis, Salomeja; Wallace-Scroggs, Allyson; Stenstrom, Judy; Maunder, Richard

    2007-01-01

    The use of rapid response teams is a relatively new approach for decreasing or eliminating codes in acute care hospitals. Based on the principles of a code team for cardiac and/or respiratory arrest in non-critical care units, the rapid response teams have specially trained nursing, respiratory, and medical personnel to respond to calls from general care units to assess and manage decompensating or rapidly changing patients before their conditions escalate to a full code situation. This article describes the processes used to develop a rapid response team, clinical indicators for triggering a rapid response team call, topics addressed in an educational program for the rapid response team members, and methods for evaluating effectiveness of the rapid response team.

  18. Problems of rapid growth.

    Science.gov (United States)

    Kim, T D

    1980-01-01

    South Korea's export-oriented development strategy has achieved a remarkable growth record, but it has also brought 2 different problems: 1) since the country's exports accounted for about 1% of total world export volume, the 1st world has become fearful about Korea's aggressive export drive; and 2) the fact that exports account for over 30% of its total gross national product (GNP) exposes the vulnerability of South Korea's economy itself. South Korea continues to be a poor nation, although it is rated as 1 of the most rapidly growing middle income economies. A World Bank 1978 report shows Korea to be 28th of 58 middle income countries in terms of per capita GNP in 1976. Of 11 newly industrializing countries (NIC), 5 in the European continent are more advanced than the others. A recent emphasis on the basic human needs approach has tended to downgrade the concept of GNP. Korea has only an abundant labor force and is without any natural resources. Consequently, Korea utilized an export-oriented development strategy. Oil requirements are met with imports, and almost all raw materials to be processed into exportable products must be imported. To pay import bills Korea must export and earn foreign exchange. It must be emphasized that foreign trade must always be 2-way traffic. In order to export more to middle income countries like Korea, the countries of the 1st world need to ease their protectionist measures against imports from developing countries.

  19. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  20. Rapidly rotating red giants

    Science.gov (United States)

    Gehan, Charlotte; Mosser, Benoît; Michel, Eric

    2017-10-01

    Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, wich behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the identification of mode crossings is precise and efficient. The determination of the mean core rotation directly derives from the precise measurement of the asymptotic period spacing ΔΠ1 and of the frequency at which the crossing of the rotational components is observed.

  1. Thermal and mechanical effect during rapid heating of astroloy for improving structural integrity

    Energy Technology Data Exchange (ETDEWEB)

    Popoolaa, A.P.I., E-mail: popoolaapi@tut.ac.za [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Oluwasegun, K.M. [Department of Materials Science and Engineering, Obafemi Awolowo University (Nigeria); Olorunniwo, O.E., E-mail: segun_nniwo@yahoo.com [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Materials Science and Engineering, Obafemi Awolowo University (Nigeria); Atanda, P.O. [Department of Materials Science and Engineering, Obafemi Awolowo University (Nigeria); Aigbodion, V.S. [Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria (South Africa); Department of Metallurgical and Materials Engineering, University of Nigeria, Nsukka (Nigeria)

    2016-05-05

    The behaviour of γ′ phase to thermal and mechanical effects during rapid heating of Astroloy(Turbine Disc alloy) a Powder metallurgy (PM) nickel base superalloy has been investigated. The thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ) microstructure of an inertia friction welded Astroloy were simulated using a Gleeble thermo-mechanical simulation system. Detailed microstructural examination of the simulated TMAZ and HAZ and those present in actual inertial friction welded specimens showed that γ′ particles persisted during rapid heating up to a temperature where the formation of liquid is thermodynamically favoured, and subsequently re-solidified eutectically. The result obtained showed that forging during the thermo-mechanical simulation significantly enhanced resistance to weld liquation cracking of the alloy. This is attributable to strain-induced rapid isothermal dissolution of the constitutional liquation products within 150 μm from the centre of the forged sample. This was not observed in purely thermally simulated samples. The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens. - Highlights: • The behaviour of γ′ phase to thermal and mechanical effects during rapid heating of Astrology • The thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ). • significantly enhanced resistance to weld liquation cracking of the alloy. • This was not observed in purely thermally simulated samples. • The microstructure within the TMAZ of the as-welded alloy is similar to the microstructure in the forged Gleeble specimens.

  2. Rapid mixing kinetic techniques.

    Science.gov (United States)

    Martin, Stephen R; Schilstra, Maria J

    2013-01-01

    Almost all of the elementary steps in a biochemical reaction scheme are either unimolecular or bimolecular processes that frequently occur on sub-second, often sub-millisecond, time scales. The traditional approach in kinetic studies is to mix two or more reagents and monitor the changes in concentrations with time. Conventional spectrophotometers cannot generally be used to study reactions that are complete within less than about 20 s, as it takes that amount of time to manually mix the reagents and activate the instrument. Rapid mixing techniques, which generally achieve mixing in less than 2 ms, overcome this limitation. This chapter is concerned with the use of these techniques in the study of reactions which reach equilibrium; the application of these methods to the study of enzyme kinetics is described in several excellent texts (Cornish-Bowden, Fundamentals of enzyme kinetics. Portland Press, 1995; Gutfreund, Kinetics for the life sciences. Receptors, transmitters and catalysis. Cambridge University Press, 1995).There are various ways to monitor changes in concentration of reactants, intermediates and products after mixing, but the most common way is to use changes in optical signals (absorbance or fluorescence) which often accompany reactions. Although absorbance can sometimes be used, fluorescence is often preferred because of its greater sensitivity, particularly in monitoring conformational changes. Such methods are continuous with good time resolution but they seldom permit the direct determination of the concentrations of individual species. Alternatively, samples may be taken from the reaction volume, mixed with a chemical quenching agent to stop the reaction, and their contents assessed by techniques such as HPLC. These methods can directly determine the concentrations of different species, but are discontinuous and have a limited time resolution.

  3. Rapid Active Sampling Package

    Science.gov (United States)

    Peters, Gregory

    2010-01-01

    A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni

  4. Rapid Robot Design Validation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies will create a comprehensive software infrastructure for rapid validation of robotic designs. The software will support push-button validation...

  5. Rapid Robot Design Validation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Energid Technologies will create a comprehensive software infrastructure for rapid validation of robot designs. The software will support push-button validation...

  6. Rapid prototyping in medical sciences

    Directory of Open Access Journals (Sweden)

    Ákos Márk Horváth

    2015-09-01

    Full Text Available Even if it sound a bit incredible rapid prototyping (RPT as production method has been used for decades in other professions. Nevertheless medical science just started discover the possibilities of this technology and use the offered benefits of 3D printing. In this paper authors have investigated the pharmaceutical usage of rapid prototyping.

  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. Subchondral pre-solidified chitosan/blood implants elicit reproducible early osteochondral wound-repair responses including neutrophil and stromal cell chemotaxis, bone resorption and repair, enhanced repair tissue integration and delayed matrix deposition

    Science.gov (United States)

    2013-01-01

    Background In this study we evaluated a novel approach to guide the bone marrow-driven articular cartilage repair response in skeletally aged rabbits. We hypothesized that dispersed chitosan particles implanted close to the bone marrow degrade in situ in a molecular mass-dependent manner, and attract more stromal cells to the site in aged rabbits compared to the blood clot in untreated controls. Methods Three microdrill hole defects, 1.4 mm diameter and 2 mm deep, were created in both knee trochlea of 30 month-old New Zealand White rabbits. Each of 3 isotonic chitosan solutions (150, 40, 10 kDa, 80% degree of deaceylation, with fluorescent chitosan tracer) was mixed with autologous rabbit whole blood, clotted with Tissue Factor to form cylindrical implants, and press-fit in drill holes in the left knee while contralateral holes received Tissue Factor or no treatment. At day 1 or day 21 post-operative, defects were analyzed by micro-computed tomography, histomorphometry and stereology for bone and soft tissue repair. Results All 3 implants filled the top of defects at day 1 and were partly degraded in situ at 21 days post-operative. All implants attracted neutrophils, osteoclasts and abundant bone marrow-derived stromal cells, stimulated bone resorption followed by new woven bone repair (bone remodeling) and promoted repair tissue-bone integration. 150 kDa chitosan implant was less degraded, and elicited more apoptotic neutrophils and bone resorption than 10 kDa chitosan implant. Drilled controls elicited a poorly integrated fibrous or fibrocartilaginous tissue. Conclusions Pre-solidified implants elicit stromal cells and vigorous bone plate remodeling through a phase involving neutrophil chemotaxis. Pre-solidified chitosan implants are tunable by molecular mass, and could be beneficial for augmented marrow stimulation therapy if the recruited stromal cells can progress to bone and cartilage repair. PMID:23324433

  9. How Rapid is Rapid Prototyping? Analysis of ESPADON Programme Results

    Directory of Open Access Journals (Sweden)

    Ian D. Alston

    2003-05-01

    Full Text Available New methodologies, engineering processes, and support environments are beginning to emerge for embedded signal processing systems. The main objectives are to enable defence industry to field state-of-the-art products in less time and with lower costs, including retrofits and upgrades, based predominately on commercial off the shelf (COTS components and the model-year concept. One of the cornerstones of the new methodologies is the concept of rapid prototyping. This is the ability to rapidly and seamlessly move from functional design to the architectural design to the implementation, through automatic code generation tools, onto real-time COTS test beds. In this paper, we try to quantify the term “rapid” and provide results, the metrics, from two independent benchmarks, a radar and sonar beamforming application subset. The metrics show that the rapid prototyping process may be sixteen times faster than a conventional process.

  10. Containerless processing and rapid solidification of Nb-Si alloys of hypereutectic composition

    Science.gov (United States)

    Hofmeister, W. H.; Bayuzick, R. J.; Robinson, M. B.; Bertero, G. A.

    1991-01-01

    A combination of bulk undercooling in an electromagnetic levitation apparatus and splat quenching between two copper plates is used to process Nb-Si alloys in order to maximize rapid solidification conditions and minimize the effects of recalescence, with emphasis on the solidification of characteristics of alloys in the 21 to 27 at. pct Si range of composition. SEM and TEM as well as X-ray diffraction are used to characterize the microstructures of the processed samples. In the range of compositions studied, the splat-quenched drops always formed the tetragonal Nb3Si phase directly from the liquid. Drops solidified in the coil were characterized by the presence of the primary intermetallic Nb5Si3 and the absence of both peritectic Nb3Si and the equilibrium eutectic. In these cases, a metastable alpha-Nb + beta-Nb5Si3 eutectic formed. The results are discussed in terms of possible metastable configurations of the Nb-Si phase diagram as well as concepts of nucleation and growth kinetics applied to the Nb3Si and Nb5Si3 intermetallics.

  11. Recyclable bio-reagent for rapid and selective extraction of contaminants from soil

    Energy Technology Data Exchange (ETDEWEB)

    Lomasney, H.L. [ISOTRON Corp., New Orleans, LA (United States)

    1997-10-01

    This Phase I Small Business Innovation Research program is confirming the effectiveness of a bio-reagent to cost-effectively and selectively extract a wide range of heavy metals and radionuclide contaminants from soil. This bioreagent solution, developed by ISOTRON{reg_sign} Corporation (New Orleans, LA), is flushed through the soil and recycled after flowing through an electrokinetic separation module, also developed by ISOTRON{reg_sign}. The process is ex situ, and the soil remains in its transport container through the decontamination process. The transport container can be a fiberglass box, or a bulk bag or {open_quotes}super sack.{close_quotes} Rocks, vegetation, roots, etc. need not be removed. High clay content soils are accommodated. The process provides rapid injection of reagent solution, and when needed, sand is introduced to speed up the heap leach step. The concentrated waste form is eventually solidified. The bio-reagent is essentially a natural product, therefore any solubizer residual in soil is not expected to cause regulatory concern. The Phase I work will confirm the effectiveness of this bio-reagent on a wide range of contaminants, and the engineering parameters that are needed to carry out a full-scale demonstration of the process. ISOTRON{reg_sign} scientists will work with contaminated soil from Los Alamos National Laboratory. LANL is in the process of decontaminating and decommissioning more than 300 sites within its complex, many of which contain heavy metals or radionuclides; some are mixed wastes containing TCE, PCB, and metals.

  12. A Rapid Coliform Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC, in collaboration with Lucigen, proposes a rapid genetic detector for spaceflight water systems to enable real-time detection of E-coli with minimal...

  13. Rapid Multiplex Microbial Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC, in collaboration with Lucigen, proposes a rapid nucleic acid-based detector for spaceflight water systems to enable simultaneous quantification of multiple...

  14. Improved stress corrosion cracking resistance of a novel biodegradable EW62 magnesium alloy by rapid solidification, in simulated electrolytes.

    Science.gov (United States)

    Hakimi, O; Aghion, E; Goldman, J

    2015-06-01

    The high corrosion rate of magnesium (Mg) and Mg-alloys precludes their widespread acceptance as implantable biomaterials. Here, we investigated the potential for rapid solidification (RS) to increase the stress corrosion cracking (SCC) resistance of a novel Mg alloy, Mg-6%Nd-2%Y-0.5%Zr (EW62), in comparison to its conventionally cast (CC) counterpart. RS ribbons were extrusion consolidated in order to generate bioimplant-relevant geometries for testing and practical use. Microstructural characteristics were examined by SEM. Corrosion rates were calculated based upon hydrogen evolution during immersion testing. The surface layer of the tested alloys was analyzed by X-ray photoelectron spectroscopy (XPS). Stress corrosion resistance was assessed by slow strain rate testing and fractography. The results indicate that the corrosion resistance of the RS alloy is significantly improved relative to the CC alloy due to a supersaturated Nd enrichment that increases the Nd2O3 content in the external oxide layer, as well as a more homogeneous structure and reduced grain size. These improvements contributed to the reduced formation of hydrogen gas and hydrogen embrittlement, which reduced the SCC sensitivity relative to the CC alloy. Therefore, EW62 in the form of a rapidly solidified extruded structure may serve as a biodegradable implant for biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. TEM Studies of Boron-Modified 17Cr-7Ni Precipitation-Hardenable Stainless Steel via Rapid Solidification Route

    Science.gov (United States)

    Gupta, Ankur; Bhargava, A. K.; Tewari, R.; Tiwari, A. N.

    2013-09-01

    Commercial grade 17Cr-7Ni precipitation-hardenable stainless steel has been modified by adding boron in the range 0.45 to 1.8 wt pct and using the chill block melt-spinning technique of rapid solidification (RS). Application of RS has been found to increase the solid solubility of boron and hardness of 17Cr-7Ni precipitation-hardenable stainless steel. The hardness of the boron-modified rapidly solidified alloys has been found to increase up to ~280 pct after isochronal aging to peak hardness. A TEM study has been carried out to understand the aging behavior. The presence of M23(B,C)6 and M2(B,C) borocarbides and epsilon-carbide in the matrix of austenite and ferrite with a change in heat treatment temperature has been observed. A new equation for Creq is also developed which includes the boron factor on ferrite phase stability. The study also emphasizes that aluminum only takes part in ferrite phase stabilization and remains in the solution.

  16. Effect of rapid quenching on the magnetic state, electrical resistivity and thermomagnetic properties of Gd{sub 3}Co

    Energy Technology Data Exchange (ETDEWEB)

    Shishkin, D.A., E-mail: shishkin@imp.uran.ru [Institute of Metal Physics, Russian Academy of Sciences, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences, Ural Federal University, 620083 Ekaterinburg (Russian Federation); Proshkin, A.V. [Institute of Metal Physics, Russian Academy of Sciences, 620137 Ekaterinburg (Russian Federation); Selezneva, N.V. [Institute of Natural Sciences, Ural Federal University, 620083 Ekaterinburg (Russian Federation); Gerasimov, E.G.; Terentev, P.B. [Institute of Metal Physics, Russian Academy of Sciences, 620137 Ekaterinburg (Russian Federation); Chirkova, A.M. [IFW Dresden, PO Box 270118, 01171 Dresden (Germany); Institute of Metal Physics, Russian Academy of Sciences, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences, Ural Federal University, 620083 Ekaterinburg (Russian Federation); Nenkov, K.; Schultz, L. [IFW Dresden, PO Box 270118, 01171 Dresden (Germany); Baranov, N.V. [Institute of Metal Physics, Russian Academy of Sciences, 620137 Ekaterinburg (Russian Federation); Institute of Natural Sciences, Ural Federal University, 620083 Ekaterinburg (Russian Federation)

    2015-10-25

    The ac-susceptibility, magnetization, electrical resistivity and specific heat measurements have been performed to study the changes in the magnetic state and physical properties of the antiferromagnetic Gd{sub 3}Co compound after rapid quenching from the liquid melt. It has been observed that the amorphization of Gd{sub 3}Co modifies the magnetic state from antiferromagnetic to a soft-ferromagnetic like behavior, increases the magnetic ordering temperature (by about 30%) and leads to substantial changes in the specific heat and electrical resistivity. A considerable enhancement of the exchange interactions in the rapidly solidified Gd{sub 3}Co is ascribed to the appearance of a magnetic moment on Co atoms up to 1.6 μ{sub B}. - Highlights: • The compound Gd{sub 3}Co has been amorphized by the melt-spinning technique. • Amorphization of Gd{sub 3}Co increases the magnetic ordering temperature by 30%. • Gd{sub 3}Co is supposed to exhibit a ferrimagnetic order after amorphization. • A magnetic moment on Co atoms is suggested to appear after amorphization of Gd{sub 3}Co. • Amorphization substantially modifies the resistivity and specific heat of Gd{sub 3}Co.

  17. Composites by rapid prototyping technology

    CSIR Research Space (South Africa)

    Kumar, S

    2010-02-01

    Full Text Available powder is a fiber, problems of manufacturing occur. The method has also been used to make Metal Matrix Composite (MMC), e.g Fe and graphite [17], WC-Co [18,19], WC-Co and Cu [20,21], Fe, Ni and TiC [22] etc and Ceramic Matrix Composite (CMC) e.g. Si... of various materials used. Key words: : Rapid Prototyping (RP), Laser, Composites 1 Introduction Rapid Prototyping (RP) initially focussed on polymers. These were later re- placed/supplemented by ceramics, metals and composites. Composites are used in RP...

  18. NIAAA's Rapid Response to College Drinking Problems Initiative: Reinforcing the Use of Evidence-Based Approaches in College Alcohol Prevention*

    Science.gov (United States)

    DeJong, William; Larimer, Mary E.; Wood, Mark D.; Hartman, Roger

    2009-01-01

    Objective: The National Institute on Alcohol Abuse and Alcoholism (NIAAA) created the Rapid Response to College Drinking Problems initiative so that senior college administrators facing an alcohol-related crisis could get assistance from well-established alcohol researchers and NIAAA staff. Method: Based on a competitive grant process, NIAAA selected five teams of research scientists with expertise in college drinking research. NIAAA then invited college administrators to propose interventions to address a recently experienced alcohol-related problem. Between September 2004 and September 2005, NIAAA selected 15 sites and paired each recipient college with a scientific team. Together, each program development/evaluation team, working closely with NIAAA scientific staff, jointly designed, implemented, and evaluated a Rapid Response project. Results: This supplement reports the results of several Rapid Response projects, plus other findings of interest that emerged from that research. Eight articles present evaluation findings for prevention and treatment interventions, which can be grouped by the individual, group/interpersonal, institutional, and community levels of the social ecological framework. Additional studies provide further insights that can inform prevention and treatment programs designed to reduce alcohol-related problems among college students. This article provides an overview of these findings, placing them in the context of the college drinking intervention literature. Conclusions: College drinking remains a daunting problem on many campuses, but evidence-based strategies—such as those described in this supplement—provide hope that more effective solutions can be found. The Rapid Response initiative has helped solidify the necessary link between research and practice in college alcohol prevention and treatment. PMID:19538907

  19. Developmental evolution facilitates rapid adaptation.

    Science.gov (United States)

    Lin, Hui; Kazlauskas, Romas J; Travisano, Michael

    2017-11-21

    Developmental evolution has frequently been identified as a mode for rapid adaptation, but direct observations of the selective benefits and associated mechanisms of developmental evolution are necessarily challenging to obtain. Here we show rapid evolution of greatly increased rates of dispersal by developmental changes when populations experience stringent selection. Replicate populations of the filamentous fungus Trichoderma citrinoviride underwent 85 serial transfers, under conditions initially favoring growth but not dispersal. T. citrinoviride populations shifted away from multicellular growth toward increased dispersal by producing one thousand times more single-celled asexual conidial spores, three times sooner than the ancestral genotype. Conidia of selected lines also germinated fifty percent faster. Gene expression changed substantially between the ancestral and selected fungi, especially for spore production and growth, demonstrating rapid evolution of tight regulatory control for down-regulation of growth and up-regulation of conidia production between 18 and 24 hours of growth. These changes involved both developmentally fixed and plastic changes in gene expression, showing that complex developmental changes can serve as a mechanism for rapid adaptation.

  20. Multigrade Teaching Rapid Appraisal Procedure.

    Science.gov (United States)

    Nielsen, Dean

    Multigrade classes have been recognized as part of elementary education for many years, but their special needs have been largely ignored. This manual focuses on the survey research that should predate the design of instructional management strategies in multigrade classrooms. It describes rapid and reliable ways to collect information about the…

  1. Rapid thermal processing of semiconductors

    CERN Document Server

    Borisenko, Victor E

    1997-01-01

    Rapid thermal processing has contributed to the development of single wafer cluster processing tools and other innovations in integrated circuit manufacturing environments Borisenko and Hesketh review theoretical and experimental progress in the field, discussing a wide range of materials, processes, and conditions They thoroughly cover the work of international investigators in the field

  2. Furnace for rapid thermal processing

    NARCIS (Netherlands)

    Roozeboom, F.; Duine, P.A.; Sluis, P. van der

    2001-01-01

    A Method (1) for Rapid Thermal Processing of a wafer (7), wherein the wafer (7) is heated by lamps (9), and the heat radiation is reflected by an optical switching device (15,17) which is in the reflecting state during the heating stage. During the cooling stage of the wafer (7), the heat is

  3. Rapid Energy Modeling Workflow Demonstration

    Science.gov (United States)

    2013-10-31

    BIM Building Information Modeling BPA Building Performance Analysis BTU British Thermal Unit CBECS Commercial Building ...geometry, orientation, weather, and materials, generates 3D Building Information Models ( BIM ) guided by satellite views of building footprints and...Rapid Energy Modeling (REM) workflows that employed building information modeling ( BIM ) approaches and conceptual energy analysis.

  4. Portable Diagnostics and Rapid Germination

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Zachary Spencer [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-12-01

    In the Bioenergy and Defense Department of Sandia National Laboratories, characterization of the BaDx (Bacillus anthracis diagnostic cartridge) was performed and rapid germination chemistry was investigated. BaDx was tested with complex sample matrixes inoculated with Bacillus anthracis, and the trials proved that BaDx will detect Bacillus anthracis in a variety of the medium, such as dirt, serum, blood, milk, and horse fluids. The dimensions of the device were altered to accommodate an E. coli or Listeria lateral flow immunoassay, and using a laser printer, BaDx devices were manufactured to identify E. coli and Listeria. Initial testing with E. coli versions of BaDx indicate that the device will be viable as a portable diagnostic cartridge. The device would be more effective with faster bacteria germination; hence studies were performed the use of rapid germination chemistry. Trials with calcium dipicolinic acid displayed increased cell germination, as shown by control studies using a microplate reader. Upon lyophilization the rapid germination chemistry failed to change growth patterns, indicating that the calcium dipicolinic acid was not solubilized under the conditions tested. Although incompatible with the portable diagnostic device, the experiments proved that the rapid germination chemistry was effective in increasing cell germination.

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

    McManus, R.W. [SOUND Environmental Services, Inc., Dallas, TX (United States); Grajczak, P. [ARCO, Los Angeles, CA (United States); Wilcoxson, J.C. [ARCO, Plano, TX (United States); Webster, S.D. [Environmental Protection Agency, Dallas, TX (United States)

    1997-12-31

    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.

  6. Dual extraction based on solid phase extraction and solidified floating organic drop microextraction for speciation of arsenic and its distribution in tea leaves and tea infusion by electrothermal vaporization ICP-MS.

    Science.gov (United States)

    Chen, Shizhong; Li, Jianfen; Lu, Dengbo; Zhang, Yan

    2016-11-15

    A dual extraction based on solid phase extraction (SPE) and solidified floating organic drop microextraction (SFODME) was developed for As species in tea leaves and tea infusion by electrothermal vaporization inductively coupled plasma mass spectrometry, including total, suspended, soluble, organic and inorganic As as well as As(III) and As(V). In SPE step, titanium dioxide nanotubes were used for preconcentration of analytes and removal of sample matrix. Elution solution from SPE was employed for further preconcentration and separation of analytes with SFODME. Under optimal conditions, detection limits of this method were 0.046 and 0.072pgmL(-1) with relative standard deviations of 6.3% and 5.8% for As(III) and As(V) (n=9, c=1.0ngmL(-1)), respectively. A preconcentration factor of 500-fold was achieved for As(III) and As(V). This method was successfully applied for analysis of speciation of arsenic and its distribution in tea leaves, tea infusion and certified reference material of tea leaves. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Strength of roadbeds built of solidified coal ash or foamed asphalt. Application thereof to temporary roads for construction work in Tachibanawan power plant site; Sekitanbai kokatai roban to formed asphalt roban no kyodo tokusei. Tachibanawan hatsudensho konai kari doro eno tekiyo jirei to hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Suesawa, H.; Iwahara, H.; Isakura, M. [Shikoku Electric Power Co., Inc., Kagawa (Japan)

    1998-11-05

    For the construction of a solidified coal ash roadbed, desulfurized gypsum and a small amount of slaked lime are added to coal ash that is the main material, moisture is adjusted, the resultant moist powder is mixed in a screw-type mixer and transported aboard a dump truck to the construction site, and then solidified by rollers. The material is easy to install, and the roadbed is high in serviceability. With no serious damage occurring in the paved surface for nine months after the placement, the road keeps on functioning satisfactorily as a provisional road for use in the execution of the construction work. Foamed asphalt is prepared by adding water to asphalt in the liquid state at high temperature for the formation of fine foam for a 10-15 times expansion of the asphalt volume. Such asphalt is lower in surface tension and enhanced in adhesiveness to other materials, and mixes completely with the road materials at normal temperature for the construction of a reinforced roadbed. The foamed asphalt covers only fine aggregate but not coarse aggregate, and the latter is tightly solidified by bitumen etc. by tamping for the realization of a strong structure. Foamed asphalt is a material that works effectively when used for a road where dynamic load is dominant. 8 refs., 18 figs., 7 tabs.

  8. Rapid scenarios and observed intensities

    OpenAIRE

    Franco Pettenati; Livio Sirovich

    2012-01-01

    After a destructive earthquake, national Governments need to know the approximate amount of damage, the number of casualties, and the financial losses as soon as possible. Rapid scenarios are also used to inform the general public; see the widely used Shakemap package [Wald et al. 1999, 2006] of the US Geological Survey (USGS) and the one modified by the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology), which is reproduced for Figure 1. T...

  9. Rapid synthesis of beta zeolites

    Science.gov (United States)

    Fan, Wei; Chang, Chun -Chih; Dornath, Paul; Wang, Zhuopeng

    2015-08-18

    The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.

  10. Rapid scenarios and observed intensities

    Directory of Open Access Journals (Sweden)

    Franco Pettenati

    2012-10-01

    Full Text Available After a destructive earthquake, national Governments need to know the approximate amount of damage, the number of casualties, and the financial losses as soon as possible. Rapid scenarios are also used to inform the general public; see the widely used Shakemap package [Wald et al. 1999, 2006] of the US Geological Survey (USGS and the one modified by the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology, which is reproduced for Figure 1. The general matter of the use of intensities in damage scenarios was discussed in a special session at the 2008 Annual Meeting of the Seismological Society of America (http://www.seismosoc.org/meetings/2008/specialsessions.html, and was also discussed in the NIS-1 session of the European Congress in Moscow, in August 2012 (http://www.esc2012-moscow.org/esc_thematicareas.html. The purposes of the present report are to: (i compare different types of intensities; (ii check two rapid scenarios of intensity; and (iii understand whether the KF formula [Sirovich 1996, Sirovich et al. 2009] can be used as a new 'attenuation' relationship to improve rapid scenarios. […

  11. Rapid diagnosis of mycobacterial infections

    Directory of Open Access Journals (Sweden)

    Michel Drancourt

    2015-01-01

    Full Text Available While pulmonary tuberculosis (PTB remains an important public health issue worldwide, there is an emerging interest in non-tuberculous mycobacteria (NTM which is responsible for opportunistic infections of the respiratory tract as well as other anatomical sites in both developed and developing countries. In this context the one goal of the clinical mycobacteriology laboratories is to provide physicians with an accurate identification of the mycobacterium as rapidly as possible. During the last ten years, several lines of laboratory tools have been developed in order to speed the isolation and identification of mycobacteria from clinical specimens. Chiefly, the composition of culture medium was renewed along with the protocol of incubation in order to recover Mycobacterium tuberculosis (MTB micro-colonies as soon as 48 h after the inoculation of the specimen. MALDI-TOF rapid identification is clearly the tool to be implemented in the laboratory for the rapid identification of the micro-colonies. Also, molecular tools and genomics are necessary in order to depict new mycobacteria species, including those of the Mycobacterium abscessus complex and the Mycobacterium avium complex. All these tools and their connections will be presented during this conference.

  12. Stirring-controlled solidified floating solid-liquid drop microextraction as a new solid phase-enhanced liquid-phase microextraction method by exploiting magnetic carbon nanotube-nickel hybrid.

    Science.gov (United States)

    Ghazaghi, Mehri; Mousavi, Hassan Zavvar; Shirkhanloo, Hamid; Rashidi, Alimorad

    2017-01-25

    A specific technique is introduced to overcome limitations of classical solidification of floating organic drop microextraction, such as tedious and time-consuming centrifuge step and using disperser solvent, by facile and efficient participation of solid and liquid phases. In this proposed method of stirring-controlled solidified floating solid-liquid drop microextraction (SC-SF-SLDME), magnetic carbon nanotube-nickel hybrid (MNi-CNT) as a solid part of the extractors are dispersed ultrasonically in sample solution, and the procedure followed by dispersion of liquid phase (1-undecanol) through high-rate stirring and easily recollection of MNi-CNT in organic solvent droplets through hydrophobic force. With the reduction in speed of stirring, one solid-liquid drop is formed on top of the solution. MNi-CNT acts as both extractor and the coalescence helper between organic droplets for a facile recollection. MNi-CNT was prepared by spray pyrolysis of nickel oleate/toluene mixture at 1000 °C. Four tyrosine kinase inhibitors were selected as model analytes and the effecting parameters were investigated. The results confirmed that magnetic nanoadsorbent has an important role in the procedure and complete collection of dispersed solvent is not achieved in the absence of the solid phase. Also, short extraction time exhibited success of the proposed method and effect of dispersed solid/liquid phases. The limits of quantification (LOQs) for imatinib, sunitinib, erlotinib, and nilotinib were determined to be as low as 0.7, 1.7, 0.6, and 1.0 μg L(-1), respectively. The intra-day precisions (RSDs) were lower than 4.5%. Method performance was investigated by determination of mentioned tyrosine kinase inhibitors (TKIs) in human serum and cerebrospinal fluid samples with good recoveries in the range of 93-98%. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Wyoming Basin Rapid Ecoregional Assessment

    Science.gov (United States)

    Carr, Natasha B.; Melcher, Cynthia P.

    2015-08-28

    The Wyoming Basin Rapid Ecoregional Assessment was conducted in partnership with the Bureau of Land Management (BLM). The overall goals of the BLM Rapid Ecoregional Assessments (REAs) are to identify important ecosystems and wildlife habitats at broad spatial scales; identify where these resources are at risk from Change Agents, including development, wildfire, invasive species, disease and climate change; quantify cumulative effects of anthropogenic stressors; and assess current levels of risk to ecological resources across a range of spatial scales and jurisdictional boundaries by assessing all lands within an ecoregion. There are several components of the REAs. Management Questions, developed by the BLM and stakeholders for the ecoregion, identify the regionally significant information needed for addressing land-management responsibilities. Conservation Elements represent regionally significant species and ecological communities that are of management concern. Change Agents that currently affect or are likely to affect the condition of species and communities in the future are identified and assessed. REAs also identify areas that have high conservation potential that are referred to as “large intact areas.” At the ecoregion level, the ecological value of large intact areas is based on the assumption that because these areas have not been greatly altered by human activities (such as development), they are more likely to contain a variety of plant and animal communities and to be resilient and resistant to changes resulting from natural disturbances such as fire, insect outbreaks, and disease.

  14. Rapid self-healing hydrogels

    Science.gov (United States)

    Phadke, Ameya; Zhang, Chao; Arman, Bedri; Hsu, Cheng-Chih; Mashelkar, Raghunath A.; Lele, Ashish K.; Tauber, Michael J.; Arya, Gaurav; Varghese, Shyni

    2012-01-01

    Synthetic materials that are capable of autonomous healing upon damage are being developed at a rapid pace because of their many potential applications. Despite these advancements, achieving self-healing in permanently cross-linked hydrogels has remained elusive because of the presence of water and irreversible cross-links. Here, we demonstrate that permanently cross-linked hydrogels can be engineered to exhibit self-healing in an aqueous environment. We achieve this feature by arming the hydrogel network with flexible-pendant side chains carrying an optimal balance of hydrophilic and hydrophobic moieties that allows the side chains to mediate hydrogen bonds across the hydrogel interfaces with minimal steric hindrance and hydrophobic collapse. The self-healing reported here is rapid, occurring within seconds of the insertion of a crack into the hydrogel or juxtaposition of two separate hydrogel pieces. The healing is reversible and can be switched on and off via changes in pH, allowing external control over the healing process. Moreover, the hydrogels can sustain multiple cycles of healing and separation without compromising their mechanical properties and healing kinetics. Beyond revealing how secondary interactions could be harnessed to introduce new functions to chemically cross-linked polymeric systems, we also demonstrate various potential applications of such easy-to-synthesize, smart, self-healing hydrogels. PMID:22392977

  15. Rapid generalization in phonotactic learning

    Directory of Open Access Journals (Sweden)

    Tal Linzen

    2017-10-01

    Full Text Available Speakers judge novel strings to be better potential words of their language if those strings consist of sound sequences that are attested in the language. These intuitions are often generalized to new sequences that share some properties with attested ones: Participants exposed to an artificial language where all words start with the voiced stops [b] and [d] will prefer words that start with other voiced stops (e.g., [g] to words that start with vowels or nasals. The current study tracks the evolution of generalization across sounds during the early stages of artificial language learning. In Experiments 1 and 2, participants received varying amounts of exposure to an artificial language. Learners rapidly generalized to new sounds: In fact, following short exposure to the language, attested patterns were not distinguished from unattested patterns that were similar in their phonological properties to the attested ones. Following additional exposure, participants showed an increasing preference for attested sounds, alongside sustained generalization to unattested ones. Finally, Experiment 3 tested whether participants can rapidly generalize to new sounds based on a single type of sound. We discuss the implications of our results for computational models of phonotactic learning.

  16. Rapid ISS Power Availability Simulator

    Science.gov (United States)

    Downing, Nicholas

    2011-01-01

    The ISS (International Space Station) Power Resource Officers (PROs) needed a tool to automate the calculation of thousands of ISS power availability simulations used to generate power constraint matrices. Each matrix contains 864 cells, and each cell represents a single power simulation that must be run. The tools available to the flight controllers were very operator intensive and not conducive to rapidly running the thousands of simulations necessary to generate the power constraint data. SOLAR is a Java-based tool that leverages commercial-off-the-shelf software (Satellite Toolkit) and an existing in-house ISS EPS model (SPEED) to rapidly perform thousands of power availability simulations. SOLAR has a very modular architecture and consists of a series of plug-ins that are loosely coupled. The modular architecture of the software allows for the easy replacement of the ISS power system model simulator, re-use of the Satellite Toolkit integration code, and separation of the user interface from the core logic. Satellite Toolkit (STK) is used to generate ISS eclipse and insulation times, solar beta angle, position of the solar arrays over time, and the amount of shadowing on the solar arrays, which is then provided to SPEED to calculate power generation forecasts. The power planning turn-around time is reduced from three months to two weeks (83-percent decrease) using SOLAR, and the amount of PRO power planning support effort is reduced by an estimated 30 percent.

  17. KEPLER RAPIDLY ROTATING GIANT STARS

    Energy Technology Data Exchange (ETDEWEB)

    Costa, A. D.; Martins, B. L. Canto; Bravo, J. P.; Paz-Chinchón, F.; Chagas, M. L. das; Leão, I. C.; Oliveira, G. Pereira de; Silva, R. Rodrigues da; Roque, S.; Oliveira, L. L. A. de; Silva, D. Freire da; De Medeiros, J. R., E-mail: renan@dfte.ufrn.br [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Campus Universitário, Natal RN (Brazil)

    2015-07-10

    Rapidly rotating giant stars are relatively rare and may represent important stages of stellar evolution, resulting from stellar coalescence of close binary systems or accretion of substellar companions by their hosting stars. In the present Letter, we report 17 giant stars observed in the scope of the Kepler space mission exhibiting rapid rotation behavior. For the first time, the abnormal rotational behavior for this puzzling family of stars is revealed by direct measurements of rotation, namely from photometric rotation period, exhibiting a very short rotation period with values ranging from 13 to 55 days. This finding points to remarkable surface rotation rates, up to 18 times the rotation of the Sun. These giants are combined with six others recently listed in the literature for mid-infrared (IR) diagnostics based on Wide-field Infrared Survey Explorer information, from which a trend for an IR excess is revealed for at least one-half of the stars, but at a level far lower than the dust excess emission shown by planet-bearing main-sequence stars.

  18. Rapid starting methanol reactor system

    Science.gov (United States)

    Chludzinski, Paul J.; Dantowitz, Philip; McElroy, James F.

    1984-01-01

    The invention relates to a methanol-to-hydrogen cracking reactor for use with a fuel cell vehicular power plant. The system is particularly designed for rapid start-up of the catalytic methanol cracking reactor after an extended shut-down period, i.e., after the vehicular fuel cell power plant has been inoperative overnight. Rapid system start-up is accomplished by a combination of direct and indirect heating of the cracking catalyst. Initially, liquid methanol is burned with a stoichiometric or slightly lean air mixture in the combustion chamber of the reactor assembly. The hot combustion gas travels down a flue gas chamber in heat exchange relationship with the catalytic cracking chamber transferring heat across the catalyst chamber wall to heat the catalyst indirectly. The combustion gas is then diverted back through the catalyst bed to heat the catalyst pellets directly. When the cracking reactor temperature reaches operating temperature, methanol combustion is stopped and a hot gas valve is switched to route the flue gas overboard, with methanol being fed directly to the catalytic cracking reactor. Thereafter, the burner operates on excess hydrogen from the fuel cells.

  19. Rapidly Developing Toxic Epidermal Necrolysis

    Directory of Open Access Journals (Sweden)

    Viktoria Oline Barrios Poulsen

    2013-01-01

    Full Text Available Severe cutaneous reactions with potentially fatal outcomes can have many different causes. The Stevens-Johnson syndrome (SJS and toxic epidermal necrolysis (TEN are rare. They are characterized by a low incidence but high mortality, and drugs are most commonly implicated. Urgent active therapy is required. Prompt recognition and withdrawal of suspect drug and rapid intervention can result in favourable outcome. No further international guidelines for treatment exist, and much of the treatment relies on old or experimental concepts with no scientific evidence. We report on a 54-year-old man experiencing rapidly developing drug-induced severe TEN and presented multiorgan failure involving the respiratory and circulatory system, coagulopathy, and renal insufficiency. Detachment counted 30% of total body surface area (TBSA. SCORTEN = 5, indicating a mortality rate >90%. The patient was sedated and mechanically ventilated, supported with fluids and inotropes to maintain a stable circulation. Component therapy was guided by thromboelastography (TEG. The patient received plasmapheresis, and shock reversal treatment was initiated. He was transferred to a specialized intensive care burn unit within 24 hours from admittance. The initial care was continued, and hemodialysis was started. Pulmonary, circulatory, and renal sequelae resolved with intensive care, and re-epithelialization progressed slowly. The patient was discharged home on hospital day 19.

  20. Rapid Adaptation in Digital Transformation

    DEFF Research Database (Denmark)

    Hansen, Anne Mette; Kræmmergaard, Pernille; Mathiassen, Lars

    2011-01-01

    the organization’s digitization approach. We demonstrate in detail how the leaders within these two organizations were engaged and offer recommendations for how other organizations can use the PPM to rapidly adapt their approaches to digital transformation through more effective IS leadership roles.......In today’s highly dynamic environments, organizational leaders need to quickly adapt existing approaches to digital transformation. However, without a shared mindset between IS and business leaders, it is difficult to adopt new approaches in response to changes in the competitive and technology...... landscape. In this article, we share insights gained from two public sector organizations in which IS and business leaders used the Participatory Process Model (PPM) designed by the authors to share their assumptions about IS leadership, challenge existing IT strategies and collaboration patterns and adapt...

  1. Moved by a Rapid Transit

    Science.gov (United States)

    Bueter, C.

    2013-04-01

    Enticing by virtue of its predictability, historical utility, and spectacle, the transit of Venus is a niche event among astronomical phenomena. Though the value of a transit for scientific purposes is now diminished, the brief appearance of Venus silhouetted against the background of the Sun in 2004 moved the artistic community to celebrate the rare alignment. Artists of all ages combined old traditions with fresh technology to create a 21st-century tapestry of music, sculpture, paintings, glasswork, quilts, sky shows, and digital imagery. A full catalog of transit-related art generated over the centuries would feature the sampling of entries presented here and at the Moved by a Rapid Transit website.

  2. [Rapid diagnostic test for malaria].

    Science.gov (United States)

    Houzé, S

    2017-02-01

    The rapid diagnostic tests (RDTs) whose main interest lies in their implementation without special equipment by unskilled personnel have grown significantly over the past fifteen years to diagnose malaria. They rely on the detection of specific Plasmodium proteins, PfHRP2, pLDH and aldolase. If the detection of PfHRP2 has very good sensitivity for the diagnosis of Plasmodium falciparum malaria, the detection of pLDH or aldolase is less efficient for other species, leaving its place to the reference microscopic diagnosis. RDT could not generally be used to monitor therapeutic efficacy because they can remain positive after clinical and parasitological cure. Furthermore, the development of the use of these tests has highlighted the need for quality assurance programs to monitor their production as their use.

  3. Rapid Solidification of Magnetic Oxides

    Science.gov (United States)

    Kalonji, G.; Deguire, M. R.

    1985-01-01

    The enhanced control over microstructural evolution inherent in rapid solidification processing techniques are exploited to create novel ceramic magnetic materials. The great sensitivity of magnetic properties to local structure provides a powerful probe both for the study of structure and of microscopic solidification mechanisms. The first system studied is the SrO-Fe2O3 binary, which contains the commercially important hard magnetic compound strontium hexaferrite. The products were analyzed by transmission electron microscopy, Mossbauer spectroscopy, magnetic measurements, and differential thermal analysis. As-quenched ribbons contain high concentrations of super-paramagnetic particles, 80 to 250 Angstroms in diameter, in a glassy matrix. This suggests the possibility of crystallizing monodomain strontium hexaferrite during subsequent heat treatment, with a resulting increase in coercivity over conventionally processed ferrite magnets. That magnetic properties can be controlled in solidification processing by varying the quench rate is demonstrated.

  4. Ceramic microfabrication by rapid prototyping process chains

    Indian Academy of Sciences (India)

    To avoid high tooling costs in product development, a rapid prototyping process chain has been established that enables rapid manufacturing of ceramic microcomponents from functional models to small lot series within a short time. This process chain combines the fast and inexpensive supply of master models by rapid ...

  5. Rapid Prototyping in Instructional Design: Creating Competencies

    Science.gov (United States)

    Fulton, Carolyn D.

    2010-01-01

    Instructional designers working in rapid prototyping environments currently do not have a list of competencies that help to identify the knowledge, skills, and attitudes (KSAs) required in these workplaces. This qualitative case study used multiple cases in an attempt to identify rapid prototyping competencies required in a rapid prototyping…

  6. Rapid Tooling via Investment Casting and Rapid Prototype Patterns

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Michael D.

    1999-06-01

    The objective of this work to develop the materials processing and design technologies required to reduce the die development time for metal mold processes from 12 months to 3 months, using die casting of Al and Mg as the example process. Sandia demonstrated that investment casting, using rapid prototype patterns produced from Stereo lithography or Selective laser Sintering, was a viable alternative/supplement to the current technology of machining form wrought stock. A demonstration die insert (ejector halt) was investment cast and subsequently tested in the die casting environment. The stationary half of the die insert was machined from wrought material to benchmark the cast half. The two inserts were run in a die casting machine for 3,100 shots of aluminum and at the end of the run no visible difference could be detected between the cast and machined inserts. Inspection concluded that the cast insert performed identically to the machined insert. Both inserts had no indications of heat checking or degradation.

  7. Double-sided electromagnetic pump with controllable normal force for rapid solidification of liquid metals

    Science.gov (United States)

    Kuznetsov, Stephen B.

    1987-01-01

    A system for casting liquid metals is provided with an electromagnetic pump which includes a pair of primary blocks each having a polyphase winding and being positioned to form a gap through which a movable conductive heat sink passes. A solidifying liquid metal sheet is deposited on the heat sink and the heat sink and sheet are held in compression by forces produced as a result of current flow through the polyphase windings. Shaded-pole interaction between the primary windings, heat sink and solidifying strip produce transverse forces which act to center the strip on the heat sink.

  8. Design and construction of the work for spoil bank of Tachibana Bay Power Station. Strength property of solidified soil and cost reduction by quality control; Tachibana Wan Htsudensho doshajo koji no sekkei to seko. Kokado no kyodo tokusei to hinshitsu kanri ni yoru kosuto teigen

    Energy Technology Data Exchange (ETDEWEB)

    Suesawa, H.; Okada, H.; Tachikawa, T. [Shikoku Electric Power Co., Inc., Takamatsu (Japan)

    1996-11-05

    The construction work of the spoil bank of Tachibana Bay Power Station, Tokushima Prefecture, is a high banking work of the total volume of banked soil of about 2.2 million m{sup 3} reaching about 50m in height, and out of the above volume of soil, about 1.2 million m{sup 3} is the soil dredged from the sea bottom generated from levee construction, etc.. Concerning this work of spoil bank, it is required to accept a great quantity of surplus soil and solidified soil at the same time while securing stability of the entire banking, and maintenance of the construction process and construction costs are very much affected by whether or not this accepting work can be promoted smoothly. Hence, securing of accepting capacity, reduction of the effects on the environment and cost reduction have been the important issues. In view of this, a core type zoning has been adopted which has compounded dimensionally the surplus soil from the power station and the solidified soil. Also in order to make the high banking of the solidified soil economical and highly reliable, it is an indispensable condition that the design uniaxial compressive strength of each zone is secured at the constant reliability, and for this purpose, the measurement of percentage of water content of the dredged soil, the quality control system to control the volume of supply of the dredged soil and cement, and the method of controlling the strength of the dredged soil have been conducted. 7 refs., 22 figs., 2 tabs.

  9. Wyoming Basin Rapid Ecoregional Assessment

    Science.gov (United States)

    Carr, Natasha B.; Means, Robert E.

    2013-01-01

    The overall goal of the Wyoming Basin Rapid Ecoregional Assessment (REA) is to provide information that supports regional planning and analysis for the management of ecological resources. The REA provides an assessment of baseline ecological conditions, an evaluation of current risks from drivers of ecosystem change (including energy development, fire, and invasive species), and a predictive capacity for evaluating future risks (including climate change). Additionally, the REA may be used for identifying priority areas for conservation or restoration and for assessing cumulative effects of multiple land uses. The Wyoming Basin REA will address Management Questions developed by the Bureau of Land Management and other agency partners for 8 major biomes and 19 species or species assemblages. The maps developed for addressing Management Questions will be integrated into overall maps of landscape-level ecological values and risks. The maps can be used to address the goals of the REA at a number of levels: for individual species, species assemblages, aquatic and terrestrial systems, and for the entire ecoregion. This allows flexibility in how the products of the REA are compiled to inform planning and management actions across a broad range of spatial scales.

  10. Rapid purification of recombinant histones.

    Directory of Open Access Journals (Sweden)

    Henrike Klinker

    Full Text Available The development of methods to assemble nucleosomes from recombinant histones decades ago has transformed chromatin research. Nevertheless, nucleosome reconstitution remains time consuming to this day, not least because the four individual histones must be purified first. Here, we present a streamlined purification protocol of recombinant histones from bacteria. We termed this method "rapid histone purification" (RHP as it circumvents isolation of inclusion bodies and thereby cuts out the most time-consuming step of traditional purification protocols. Instead of inclusion body isolation, whole cell extracts are prepared under strongly denaturing conditions that directly solubilize inclusion bodies. By ion exchange chromatography, the histones are purified from the extracts. The protocol has been successfully applied to all four canonical Drosophila and human histones. RHP histones and histones that were purified from isolated inclusion bodies had similar purities. The different purification strategies also did not impact the quality of octamers reconstituted from these histones. We expect that the RHP protocol can be readily applied to the purification of canonical histones from other species as well as the numerous histone variants.

  11. Rapid typing of Coxiella burnetii.

    Directory of Open Access Journals (Sweden)

    Heidie M Hornstra

    Full Text Available Coxiella burnetii has the potential to cause serious disease and is highly prevalent in the environment. Despite this, epidemiological data are sparse and isolate collections are typically small, rare, and difficult to share among laboratories as this pathogen is governed by select agent rules and fastidious to culture. With the advent of whole genome sequencing, some of this knowledge gap has been overcome by the development of genotyping schemes, however many of these methods are cumbersome and not readily transferable between institutions. As comparisons of the few existing collections can dramatically increase our knowledge of the evolution and phylogeography of the species, we aimed to facilitate such comparisons by extracting SNP signatures from past genotyping efforts and then incorporated these signatures into assays that quickly and easily define genotypes and phylogenetic groups. We found 91 polymorphisms (SNPs and indels among multispacer sequence typing (MST loci and designed 14 SNP-based assays that could be used to type samples based on previously established phylogenetic groups. These assays are rapid, inexpensive, real-time PCR assays whose results are unambiguous. Data from these assays allowed us to assign 43 previously untyped isolates to established genotypes and genomic groups. Furthermore, genotyping results based on assays from the signatures provided here are easily transferred between institutions, readily interpreted phylogenetically and simple to adapt to new genotyping technologies.

  12. Rapid Response Flood Water Mapping

    Science.gov (United States)

    Policelli, Fritz; Brakenridge, G. R.; Coplin, A.; Bunnell, M.; Wu, L.; Habib, Shahid; Farah, H.

    2010-01-01

    Since the beginning of operation of the MODIS instrument on the NASA Terra satellite at the end of 1999, an exceptionally useful sensor and public data stream have been available for many applications including the rapid and precise characterization of terrestrial surface water changes. One practical application of such capability is the near-real time mapping of river flood inundation. We have developed a surface water mapping methodology based on using only bands 1 (620-672 nm) and 2 (841-890 nm). These are the two bands at 250 m, and the use of only these bands maximizes the resulting map detail. In this regard, most water bodies are strong absorbers of incoming solar radiation at the band 2 wavelength: it could be used alone, via a thresholding procedure, to separate water (dark, low radiance or reflectance pixels) from land (much brighter pixels) (1, 2). Some previous water mapping procedures have in fact used such single band data from this and other sensors that include similar wavelength channels. Adding the second channel of data (band 1), however, allows a band ratio approach which permits sediment-laden water, often relatively light at band 2 wavelengths, to still be discriminated, and, as well, provides some removal of error by reducing the number of cloud shadow pixels that would otherwise be misclassified as water.

  13. Characterization of Directionally Solidified Gray Iron

    Science.gov (United States)

    Rivera, Elis A.; Christiansen, Tyler; Genau, Amber L.; Catalina, Adrian

    Even with decades of study, the complex development of solidification microstructures in cast iron is incompletely understood. Because Fe-C eutectic can produce different morphologies, and even different phases, depending on growth velocities and composition, understanding the conditions under which each forms is important. Directional solidification was used to investigate the effects of alloying additions and solidification velocity on graphite spacing in gray iron. Average and minimum spacing for five compositions, containing varied amounts of Si and Mn, and velocities from 0.5 to 5 µm/s are reported. A critical velocity of around 1 µm/s was observed, above which the graphite structure loses directionality and austenite dendrites appear. A semi-automated MATLAB code was developed for quickly and objectively measuring graphite spacing. The automated results compare favorably with traditional manual measurements, and will allow for more robust measurement of eutectic spacing in systems where the spacing is highly irregular.

  14. The Application Trends of Rapid Prototyping Manufacturing

    Directory of Open Access Journals (Sweden)

    Qiu Xiao Lin

    2016-01-01

    characteristics of laser stero lithography (LSL selective laser sintering (SLS, three-dimensional printing (DP, fused deposition modeling (FDM, computer numerical control (CNC and other rapid prototyping technologies. After discussed these five rapid prototyping technology materials, we presented the hotspot and direction of rapid prototyping technology and look forward to the development of its technique, the expansion of its field and the progress of its academic ideology.

  15. Rapid Automated Mission Planning System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is an automated UAS mission planning system that will rapidly identify emergency (contingency) landing sites, manage contingency routing, and...

  16. WIST: toolkit for rapid, customized LIMS development

    National Research Council Canada - National Science Library

    Huang, Y Wayne; Arkin, Adam P; Chandonia, John-Marc

    2011-01-01

    Workflow Information Storage Toolkit (WIST) is a set of application programming interfaces and web applications that allow for the rapid development of customized laboratory information management systems (LIMS...

  17. JIEDDO Experience Provides Rapid Acquisition Insights

    National Research Council Canada - National Science Library

    James P Craft

    2015-01-01

    .... JIDA's rapid acquisition capabilities were preserved by transitioning the expedient organization that received supplemental funding into the Defense Department's newest combat support agency (CSA...

  18. In Situ Synchrotron X-Ray Diffraction and Small Angle X-Ray Scattering Studies on Rapidly Heated and Cooled Ti-Al and Al-Cu-Mg Alloys Using Laser-Based Heating

    Science.gov (United States)

    Kenel, C.; Schloth, P.; Van Petegem, S.; Fife, J. L.; Grolimund, D.; Menzel, A.; Van Swygenhoven, H.; Leinenbach, C.

    2016-03-01

    Beam-based additive manufacturing (AM) typically involves high cooling rates in a range of 103-104 K/s. Therefore, new techniques are required to understand the non-equilibrium evolution of materials at appropriate time scales. Most technical alloys have not been optimized for such rapid solidification, and microstructural, phase, and elemental solubility behavior can be very different. In this work, the combination of complementary in situ synchrotron micro-x-ray diffraction (microXRD) and small angle x-ray scattering (SAXS) studies with laser-based heating and rapid cooling is presented as an approach to study alloy behavior under processing conditions similar to AM techniques. In rapidly solidified Ti-48Al, the full solidification and phase transformation sequences are observed using microXRD with high temporal resolution. The high cooling rates are achieved by fast heat extraction. Further, the temperature- and cooling rate-dependent precipitation of sub-nanometer clusters in an Al-Cu-Mg alloy can be studied by SAXS. The sensitivity of SAXS on the length scales of the newly formed phases allows their size and fraction to be determined. These techniques are unique tools to help provide a deeper understanding of underlying alloy behavior and its influence on resulting microstructures and properties after AM. Their availability to materials scientists is crucial for both in-depth investigations of novel alloys and also future production of high-quality parts using AM.

  19. Test plan for the Rapid Geophysical Surveyor

    Energy Technology Data Exchange (ETDEWEB)

    Roybal, L.G.

    1993-06-01

    This document describes the test plant for demonstrating and testing a set of optically pumped cesium-based total field magnetometers using the Rapid Geophysical Surveyor platform. The proposed testing will be used to assess the function of these magnetometers as deployed on the Rapid Geophysical Surveyor and evaluate the practical utility of high resolution magnetic data for supporting waste retrieval efforts.

  20. Rapid eye movement sleep behavior disorder

    DEFF Research Database (Denmark)

    Schenck, C H; Montplaisir, J Y; Frauscher, B

    2013-01-01

    We aimed to provide a consensus statement by the International Rapid Eye Movement Sleep Behavior Disorder Study Group (IRBD-SG) on devising controlled active treatment studies in rapid eye movement sleep behavior disorder (RBD) and devising studies of neuroprotection against Parkinson disease (PD...

  1. Rapid Prototyping of Mobile Learning Games

    Science.gov (United States)

    Federley, Maija; Sorsa, Timo; Paavilainen, Janne; Boissonnier, Kimo; Seisto, Anu

    2014-01-01

    This position paper presents the first results of an on-going project, in which we explore rapid prototyping method to efficiently produce digital learning solutions that are commercially viable. In this first phase, rapid game prototyping and an iterative approach was tested as a quick and efficient way to create learning games and to evaluate…

  2. Rapid methods for detection of bacteria

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Andersen, B.Ø.; Miller, M.

    2006-01-01

    Traditional methods for detection of bacteria in drinking water e.g. Heterotrophic Plate Counts (HPC) or Most Probable Number (MNP) take 48-72 hours to give the result. New rapid methods for detection of bacteria are needed to protect the consumers against contaminations. Two rapid methods...

  3. Effect of massive transformation on formation of acicular structure in austenitic stainless steel weld metal solidified as ferritic single phase. Report 5. Study on solidification and subsequent transformation of Cr-Ni stainless steel weld metals; Feraito tanso de gyokosuru osutenaito kei sutenresu ko yosetsu kinzoku ni okeru ashikyura jo soshiki no keisei ni oyobosu masshibu hentai no eikyo.5. Cr-Ni kei sutenresu ko yosetsu kinzoku no gyoko/hentai ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, H.; Koseki, T.; Okita, S.; Fuji, M. [Nippon Steel Corp., Tokyo (Japan)

    1997-05-05

    The authors clarified that massive transformation occurs at two phase region under To temperature and there is K-S relation between the massive formation phase and base phase using {gamma} stainless steel that solidifies at F mode and forms acicular structure at room temperature structure. There is a possibility of massive transformation in weld metals because the cooling rate below the high temperature To was high even for normal welding process. Thereupon, in this report, whether the massive transformation effects the formation of acicular structure or not was studied as for {gamma} stainless steel weld metal that solidifies at F mode and room temperature structure becomes acicular form of two {delta} and {gamma} phase. As a result, it was clarified that massive transformation occurs at two phase region with temperature below To, and the room temperature structure was acicular form structure irrespective to massive transformation in case of composition with small Cr/Ni ratio even in case of stainless steel that solidifies at F mode. 20 refs., 15 figs., 1 tab.

  4. TEM Characterization and Properties of Cu-1 wt.% TiB2 Nanocomposite Prepared by Rapid Solidification and Subsequent Heat Treatment

    Directory of Open Access Journals (Sweden)

    M. Sobhani

    2012-12-01

    Full Text Available Copper matrix composite reinforced by 1wt.% TiB2 particles was prepared using in situ reaction of Cu-1.4wt.% Ti and Cu-0.7wt.% B by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºC. High-resolution transmission electron microscopy (HRTEM characterization showed that primary TiB2 particles were formed in liquid copper. Heat treatment of as-solidified samples led to the formation of secondary TiB2 particles via spinodal decomposition of titanium-rich zone inside the grains. Mechanical properties (after 50% reduction in area as well as electrical conductivity of composite were evaluated after heat treatment and were compared with those of pure copper. The results indicated that, due to the formation of secondary TiB2 particles in the matrix, electrical conductivity increased along with hardness up to 10 hrs of heat treatment and reached 65% IACS and 155 HV, respectively. Moreover, the maximum ultimate (i.e. 580 MPa and yield (i.e. 555 MPa strengths of composite were achieved at this time.

  5. A new method for rapid Canine retraction

    Directory of Open Access Journals (Sweden)

    "Khavari A

    2001-06-01

    Full Text Available Distraction osteogenesis method (Do in bone lengthening and rapid midpalatal expansion have shown the great ability of osteognic tissues for rapid bone formation under distraction force and special protocol with optimum rate of one millimeter per day. Periodontal membrane of teeth (PDM is the extension of periostium in the alveolar socked. Orthodontic force distracts PDM fibers in the tension side and then bone formation will begin.Objects: Rapid retraction of canine tooth into extraction space of first premolar by DO protocol in order to show the ability of the PDM in rapid bone formation. The other objective was reducing total orthodontic treatment time of extraction cases.Patients and Methods: Tweleve maxillary canines in six patients were retracted rapidly in three weeks by a custom-made tooth-born appliance. Radiographic records were taken to evaluate the effects of heavy applied force on canine and anchorage teeth.Results: Average retraction was 7.05 mm in three weeks (2.35 mm/week. Canines rotated distal- in by mean 3.5 degrees.Anchorage loss was from 0 to 0.8 mm with average of 0.3 mm.Root resorption of canines was negligible, and was not significant clinically. Periodontium was normal after rapid retraction. No hazard for pulp vitality was observed.Discussion: PDM responded well to heavy distraction force by Do protocol. Rapid canine retraction seems to be a safe method and can considerabely reduce orthodontic time.

  6. Risks and Benefits of Rapid Clozapine Titration.

    Science.gov (United States)

    Lochhead, Jeannie D; Nelson, Michele A; Schneider, Alan L

    2016-05-18

    Clozapine is often considered the gold standard for the treatment of schizophrenia. Clinical guidelines suggest a gradual titration over 2 weeks to reduce the risks of adverse events such as seizures, hypotension, agranulocytosis, and myocarditis. The slow titration often delays time to therapeutic response. This raises the question of whether, in some patients, it may be safe to use a more rapid clozapine titration. The following case illustrates the potential risks associated with the use of multiple antipsychotics and rapid clozapine titration. We present the case of a young man with schizophrenia who developed life threatening neuroleptic malignant syndrome (NMS) during rapid clozapine titration and treatment with multiple antipsychotics. We were unable to find another case in the literature of NMS associated with rapid clozapine titration. This case is meant to urge clinicians to carefully evaluate the risks and benefits of rapid clozapine titration, and to encourage researchers to further evaluate the safety of rapid clozapine titration. Rapid clozapine titration has implications for decreasing health care costs associated with prolonged hospitalizations, and decreasing the emotional suffering associated with uncontrolled symptoms of psychosis. Clozapine is considered the most effective antipsychotic available thus efforts should focus on developing strategies that would allow for safest and most efficient use of clozapine to encourage its utilization for treatment resistance schizophrenia.

  7. Risks and benefits of rapid clozapine titration

    Directory of Open Access Journals (Sweden)

    Jeannie D. Lochhead

    2016-05-01

    Full Text Available Clozapine is often considered the gold standard for the treatment of schizophrenia. Clinical guidelines suggest a gradual titration over 2 weeks to reduce the risks of adverse events such as seizures, hypotension, agranulocytosis, and myocarditis. The slow titration often delays time to therapeutic response. This raises the question of whether, in some patients, it may be safe to use a more rapid clozapine titration. The following case illustrates the potential risks associated with the use of multiple antipsychotics and rapid clozapine titration. We present the case of a young man with schizophrenia who developed life threatening neuroleptic malignant syndrome (NMS during rapid clozapine titration and treatment with multiple antipsychotics. We were unable to find another case in the literature of NMS associated with rapid clozapine titration. This case is meant to urge clinicians to carefully evaluate the risks and benefits of rapid clozapine titration, and to encourage researchers to further evaluate the safety of rapid clozapine titration. Rapid clozapine titration has implications for decreasing health care costs associated with prolonged hospitalizations, and decreasing the emotional suffering associated with uncontrolled symptoms of psychosis. Clozapine is considered the most effective antipsychotic available thus efforts should focus on developing strategies that would allow for safest and most efficient use of clozapine to encourage its utilization for treatment resistance schizophrenia.

  8. A scoping review of rapid review methods.

    Science.gov (United States)

    Tricco, Andrea C; Antony, Jesmin; Zarin, Wasifa; Strifler, Lisa; Ghassemi, Marco; Ivory, John; Perrier, Laure; Hutton, Brian; Moher, David; Straus, Sharon E

    2015-09-16

    Rapid reviews are a form of knowledge synthesis in which components of the systematic review process are simplified or omitted to produce information in a timely manner. Although numerous centers are conducting rapid reviews internationally, few studies have examined the methodological characteristics of rapid reviews. We aimed to examine articles, books, and reports that evaluated, compared, used or described rapid reviews or methods through a scoping review. MEDLINE, EMBASE, the Cochrane Library, internet websites of rapid review producers, and reference lists were searched to identify articles for inclusion. Two reviewers independently screened literature search results and abstracted data from included studies. Descriptive analysis was conducted. We included 100 articles plus one companion report that were published between 1997 and 2013. The studies were categorized as 84 application papers, seven development papers, six impact papers, and four comparison papers (one was included in two categories). The rapid reviews were conducted between 1 and 12 months, predominantly in Europe (58 %) and North America (20 %). The included studies failed to report 6 % to 73 % of the specific systematic review steps examined. Fifty unique rapid review methods were identified; 16 methods occurred more than once. Streamlined methods that were used in the 82 rapid reviews included limiting the literature search to published literature (24 %) or one database (2 %), limiting inclusion criteria by date (68 %) or language (49 %), having one person screen and another verify or screen excluded studies (6 %), having one person abstract data and another verify (23 %), not conducting risk of bias/quality appraisal (7 %) or having only one reviewer conduct the quality appraisal (7 %), and presenting results as a narrative summary (78 %). Four case studies were identified that compared the results of rapid reviews to systematic reviews. Three studies found that the conclusions between

  9. Implementation of rapid diagnostics with antimicrobial stewardship.

    Science.gov (United States)

    Minejima, Emi; Wong-Beringer, Annie

    2016-11-01

    Antimicrobial stewardship (ASP) is an intervention-based program to improve patient outcomes to infection while limiting spread of resistance and unintended consequences. Many rapid diagnostic tools are now FDA cleared for clinical use, with three evaluated across multiple settings: Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry, Verigene, and FilmArray. Areas covered: This review will focus on studies published that evaluated ASP intervention with rapid diagnostic implementation on outcomes of infection. A description of the key ASP personnel, rapid diagnostic notification methods, hours of notification, and scope of ASP intervention is summarized. Expert commentary: It is critical that ASPs continually re-evaluate and evolve with technological advances. Rapid diagnostic tools are powerful in their ability to identify organisms quickly. A trained clinician is needed to evaluate the results and interact with the providers to educate them on result interpretation and optimal antimicrobial selection to maximize treatment success.

  10. Rapid Update Cycle (RUC) [20 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Update Cycle (RUC) weather forecast model was developed by the National Centers for Environmental Prediction (NCEP). On May 1, 2012, the RUC was replaced...

  11. Rapid Update Cycle (RUC) [13 km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Rapid Update Cycle (RUC) weather forecast model was developed by the National Centers for Environmental Prediction (NCEP). On May 1, 2012, the RUC was replaced...

  12. Rapid Chemical Exposure and Dose Research

    Science.gov (United States)

    EPA evaluates the potential risks of the manufacture and use of thousands of chemicals. To assist with this evaluation, EPA scientists developed a rapid, automated model using off the shelf technology that predicts exposures for thousands of chemicals.

  13. Innovative rapid construction/reconstruction methods.

    Science.gov (United States)

    2005-07-01

    Innovative construction and reconstruction methods provide the opportunity to significantly reduce the time of roadway projects while maintaining the necessary quality of workmanship. The need for these rapid methods stems from the increase in ...

  14. Colorado Plateau Rapid Ecoregion Assessment Data Catalog

    Data.gov (United States)

    Bureau of Land Management, Department of the Interior — Datasets used in the analysis of the Colorado Plateau (COP) Rapid Ecoregion Assessment (REA).They can be downloaded via a layer package (lpk, similar to a zip file...

  15. Development of a Rapid Thermoplastic Impregnation Device

    NARCIS (Netherlands)

    Weustink, A.P.D.

    2007-01-01

    A melt impregnation device for rapid thermoplastic impregnation of fiber bundles has been developed through modeling and experiments. The basic principles behind the thermoplastic impregnation process are investigated and the properties needed for a successful thermoplastic impregnation device are

  16. Practical implications of rapid development methodologies

    CSIR Research Space (South Africa)

    Gerber, A

    2007-11-01

    Full Text Available Rapid development methodologies are popular approaches for the development of modern software systems. The goals of these methodologies are the inclusion of the client into the analysis, design and implementation activities, as well...

  17. The Rapid Perceptual Impact of Emotional Distractors.

    Directory of Open Access Journals (Sweden)

    Briana L Kennedy

    Full Text Available The brief presentation of an emotional distractor can temporarily impair perception of a subsequent, rapidly presented target, an effect known as emotion-induced blindness (EIB. How rapidly does this impairment unfold? To probe this question, we examined EIB for targets that immediately succeeded ("lag-1" emotional distractors in a rapid stream of items relative to EIB for targets at later serial positions. Experiments 1 and 2 suggested that emotional distractors interfere with items presented very soon after them, with impaired target perception emerging as early as lag-1. Experiment 3 included an exploratory examination of individual differences, which suggested that EIB onsets more rapidly among participants scoring high in measures linked to negative affect.

  18. Rapidly curable electrically conductive clear coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Mark P.; Anderson, Lawrence G.; Post, Gordon L.

    2018-01-16

    Rapidly curable electrically conductive clear coatings are applied to substrates. The electrically conductive clear coating includes to clear layer having a resinous binder with ultrafine non-stoichiometric tungsten oxide particles dispersed therein. The clear coating may be rapidly cured by subjecting the coating to infrared radiation that heats the tungsten oxide particles and surrounding resinous binder. Localized heating increases the temperature of the coating to thereby thermally cure the coating, while avoiding unwanted heating of the underlying substrate.

  19. Rapidly separating microneedles for transdermal drug delivery.

    Science.gov (United States)

    Zhu, Dan Dan; Wang, Qi Lei; Liu, Xu Bo; Guo, Xin Dong

    2016-09-01

    The applications of polymer microneedles (MNs) into human skin emerged as an alternative of the conventional hypodermic needles. However, dissolving MNs require many minutes to be dissolved in the skin and typically have difficulty being fully inserted into the skin, which may lead to the low drug delivery efficiency. To address these issues, we introduce rapidly separating MNs that can rapidly deliver drugs into the skin in a minimally invasive way. For the rapidly separating MNs, drug loaded dissolving MNs are mounted on the top of solid MNs, which are made of biodegradable polylactic acid which eliminate the biohazardous waste. These MNs have sufficient mechanical strength to be inserted into the skin with the drug loaded tips fully embedded for subsequent dissolution. Compared with the traditional MNs, rapidly separating MNs achieve over 90% of drug delivery efficiency in 30s while the traditional MNs needs 2min to achieve the same efficiency. With the in vivo test in mice, the micro-holes caused by rapidly separating MNs can heal in 1h, indicating that the rapidly separating MNs are safe for future applications. These results indicate that the design of rapidly separating dissolvable MNs can offer a quick, high efficient, convenient, safe and potentially self-administered method of drug delivery. Polymer microneedles offer an attractive, painless and minimally invasive approach for transdermal drug delivery. However, dissolving microneedles require many minutes to be dissolved in the skin and typically have difficulty being fully inserted into the skin due to the skin deformation, which may lead to the low drug delivery efficiency. In this work we proposed rapidly separating microneedles which can deliver over 90% of drug into the skin in 30s. The in vitro and in vivo results indicate that the new design of these microneedles can offer a quick, high efficient, convenient and safe method for transdermal drug delivery. Copyright © 2016 Acta Materialia Inc

  20. Exploring data with RapidMiner

    CERN Document Server

    Chisholm, Andrew

    2013-01-01

    A step-by-step tutorial style using examples so that users of different levels will benefit from the facilities offered by RapidMiner.If you are a computer scientist or an engineer who has real data from which you want to extract value, this book is ideal for you. You will need to have at least a basic awareness of data mining techniques and some exposure to RapidMiner.

  1. Transverse vetoes with rapidity cutoff in SCET

    Science.gov (United States)

    Hornig, Andrew; Kang, Daekyoung; Makris, Yiannis; Mehen, Thomas

    2017-12-01

    We consider di-jet production in hadron collisions where a transverse veto is imposed on radiation for (pseudo-)rapidities in the central region only, where this central region is defined with rapidity cutoff. For the case where the transverse measurement (e.g., transverse energy or min p T for jet veto) is parametrically larger relative to the typical transverse momentum beyond the cutoff, the cross section is insensitive to the cutoff parameter and is factorized in terms of collinear and soft degrees of freedom. The virtuality for these degrees of freedom is set by the transverse measurement, as in typical transverse-momentum dependent observables such as Drell-Yan, Higgs production, and the event shape broadening. This paper focuses on the other region, where the typical transverse momentum below and beyond the cutoff is of similar size. In this region the rapidity cutoff further resolves soft radiation into (u)soft and soft-collinear radiation with different rapidities but identical virtuality. This gives rise to rapidity logarithms of the rapidity cutoff parameter which we resum using renormalization group methods. We factorize the cross section in this region in terms of soft and collinear functions in the framework of soft-collinear effective theory, then further refactorize the soft function as a convolution of the (u)soft and soft-collinear functions. All these functions are calculated at one-loop order. As an example, we calculate a differential cross section for a specific partonic channel, qq ' → qq ' , for the jet shape angularities and show that the refactorization allows us to resum the rapidity logarithms and significantly reduce theoretical uncertainties in the jet shape spectrum.

  2. Energy: solidifying natural gas for storage; Energie: stocker le gaz naturel en le solidifiant

    Energy Technology Data Exchange (ETDEWEB)

    Lepetit, V.

    2003-05-01

    Mitsubishi Heavy Industries and Mitsui Engineering companies (Japan) are carrying out two competitive projects of natural gas solidification for its storage and transport. The principle consists in changing natural gas into solid hydrates which are stable between -15 and +5 deg. C at atmospheric pressure and can be handled easily (1 m{sup 3} of hydrate represents 160 m{sup 3} of gas at the atmospheric pressure). The solidification method is simple: methane bubbles are introduced in a pressure vessel filled with water at a temperature of 3-5 deg. C and under a pressure of 50 bars. The mixture is shacked and the pressure is progressively lowered down to the atmospheric pressure. Flakes of ice-gas mixture occur in the vessel are are subsequently transformed into 20 mm diameter bars of high density more tolerant to temperature changes and more easily transportable. Short paper. (J.S.)

  3. Prostate treatments, 1MRT o RapidArc; Tratamiento de prostata, IMART o RapidArc?

    Energy Technology Data Exchange (ETDEWEB)

    Castro novais, J.; Ruiz Maqueda, S.; Pardo Perez, E.; Molina Lopez, M. Y.; Cerro Penalver, E.

    2015-07-01

    Techniques that modulate the dose (as IMRT or RapidArcTM) improve dose homogeneity within the target volume decreasing the dose in healthy organs. The aim of this work is to study the dosimetric differences in prostate radiotherapy treatments with IMRT and RapidArcTM. The results of the 109 patients studied show that plans to RapidArcTM have better coverage, compliance and dose gradient outside the target volume. (Author)

  4. An Exponential Regulator for Rapidity Divergences

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ye [Fermilab; Neill, Duff [MIT, Cambridge, CTP; Zhu, Hua Xing [MIT, Cambridge, CTP

    2016-04-01

    Finding an efficient and compelling regularization of soft and collinear degrees of freedom at the same invariant mass scale, but separated in rapidity is a persistent problem in high-energy factorization. In the course of a calculation, one encounters divergences unregulated by dimensional regularization, often called rapidity divergences. Once regulated, a general framework exists for their renormalization, the rapidity renormalization group (RRG), leading to fully resummed calculations of transverse momentum (to the jet axis) sensitive quantities. We examine how this regularization can be implemented via a multi-differential factorization of the soft-collinear phase-space, leading to an (in principle) alternative non-perturbative regularization of rapidity divergences. As an example, we examine the fully-differential factorization of a color singlet's momentum spectrum in a hadron-hadron collision at threshold. We show how this factorization acts as a mother theory to both traditional threshold and transverse momentum resummation, recovering the classical results for both resummations. Examining the refactorization of the transverse momentum beam functions in the threshold region, we show that one can directly calculate the rapidity renormalized function, while shedding light on the structure of joint resummation. Finally, we show how using modern bootstrap techniques, the transverse momentum spectrum is determined by an expansion about the threshold factorization, leading to a viable higher loop scheme for calculating the relevant anomalous dimensions for the transverse momentum spectrum.

  5. Rapid, generalized adaptation to asynchronous audiovisual speech.

    Science.gov (United States)

    Van der Burg, Erik; Goodbourn, Patrick T

    2015-04-07

    The brain is adaptive. The speed of propagation through air, and of low-level sensory processing, differs markedly between auditory and visual stimuli; yet the brain can adapt to compensate for the resulting cross-modal delays. Studies investigating temporal recalibration to audiovisual speech have used prolonged adaptation procedures, suggesting that adaptation is sluggish. Here, we show that adaptation to asynchronous audiovisual speech occurs rapidly. Participants viewed a brief clip of an actor pronouncing a single syllable. The voice was either advanced or delayed relative to the corresponding lip movements, and participants were asked to make a synchrony judgement. Although we did not use an explicit adaptation procedure, we demonstrate rapid recalibration based on a single audiovisual event. We find that the point of subjective simultaneity on each trial is highly contingent upon the modality order of the preceding trial. We find compelling evidence that rapid recalibration generalizes across different stimuli, and different actors. Finally, we demonstrate that rapid recalibration occurs even when auditory and visual events clearly belong to different actors. These results suggest that rapid temporal recalibration to audiovisual speech is primarily mediated by basic temporal factors, rather than higher-order factors such as perceived simultaneity and source identity. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  6. Rapid penetration into granular media visualizing the fundamental physics of rapid earth penetration

    CERN Document Server

    Iskander, Magued

    2015-01-01

    Rapid Penetration into Granular Media: Visualizing the Fundamental Physics of Rapid Earth Penetration introduces readers to the variety of methods and techniques used to visualize, observe, and model the rapid penetration of natural and man-made projectiles into earth materials. It provides seasoned practitioners with a standard reference that showcases the topic's most recent developments in research and application. The text compiles the findings of new research developments on the subject, outlines the fundamental physics of rapid penetration into granular media, and assembles a com

  7. Polyjet technology applications for rapid tooling

    Directory of Open Access Journals (Sweden)

    Udroiu Razvan

    2017-01-01

    Full Text Available Polymer Jetting (PolyJet has proved to be one of the most accurate additive manufacturing technologies, in order to manufacture rapid tools. Rapid Tooling (RT is different from conventional tooling as follow: manufacturing time is shorter, the cost is much less, but the tool life is shorter and tolerances are wider. The purpose of this paper is to make a comparative study between the soft tools (silicon moulds and hard tools (acrylic thermoplastic moulds based on the Polymer Jetting technology. Thus, two types of moulds have been made in order to manufacture a test part. Reaction injection moulding (RIM and casting techniques were used to fill these moulds with resins that simulate the plastic injection materials. Rapid tooling applications, such as indirect tooling and direct tooling, based on PolyJet technology were experimentally investigated.

  8. Rapid Hepatitis B Vaccination in Adults

    Directory of Open Access Journals (Sweden)

    Mansur Özcan

    2004-01-01

    Full Text Available Vaccination is a very important method in prevention of HBV.Especially rapid immunization takes an important place in subjects at highrisk. We have injected HBV vaccine to health workers who are attending inour hospital by rapid immunisation programme (at 0, 1 and 2 months andaimed to identify it’s efficiacy. Eighty seven subjects (69% male, 31%female were included to our study. Median age was 34 for male and 32 forwomen. We obtained 90% achievement of immunity rate after theprogramme finished. There were no significant difference between maleend female groups, and age groups. The non-responder rate was 11.6% inmale, and 7.4% in female. This rate was 6% in under 40 years old group,and 22.7% in 40 or older group. This difference was significant in twogroups statistically (p=0.02. The rapid immunization programme, weperformed has nearly the same success results as in standard programme.

  9. Effect of titanium content and cooling rate on the microstructure and martensitic transformation of rapidly solidified Ti-Ni shape memory alloys; Influencia do Ti e da taxa de resfriamento na microestrutura e na temperatura M{sub S} em ligas Ni-Ti com EMF solidificadas rapidamente

    Energy Technology Data Exchange (ETDEWEB)

    Anselmo, George Carlos dos Santos; Castro, Walman Benicio de, E-mail: georgeanselmo@yahoo.com.br, E-mail: walman.castro@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2017-01-15

    One important challenge of microsystems design is the implementation of efficient principles of miniaturized actuation at the micro-scale. Shape memory alloys (SMAs) have early 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 micro-scale processed. Alloys of composition Ni-44,8wt%Ti and Ni- 45,3wt%Ti were produced using the melt spinning method in air atmosphere. Ribbons obtained in this process showed martensitic grain size between 5 and 30 μm, depending on the alloy composition and the linear velocity of the wheel. (author)

  10. Rapid serial visual presentation design for cognition

    CERN Document Server

    Spence, Robert

    2013-01-01

    A powerful new image presentation technique has evolved over the last twenty years, and its value demonstrated through its support of many and varied common tasks. Conceptually, Rapid Serial Visual Presentation (RSVP) is basically simple, exemplified in the physical world by the rapid riffling of the pages of a book in order to locate a known image. Advances in computation and graphics processing allow RSVP to be applied flexibly and effectively to a huge variety of common tasks such as window shopping, video fast-forward and rewind, TV channel selection and product browsing. At its heart is a

  11. Accuracy of rapid disposition by emergency clinicians.

    Science.gov (United States)

    Backay, Andrew; Bystrzycki, Adam; Smit, De Villiers; Keogh, Martin; O'Reilly, Gerard; Mitra, Biswadev

    2017-05-01

    Objectives Rapid disposition protocols are increasingly being considered for implementation in emergency departments (EDs). Among patients presenting to an adult tertiary referral hospital, this study aimed to compare prediction accuracy of a rapid disposition decision at the conclusion of history and examination, compared with disposition following standard assessment. Methods Prospective observational data were collected for 1 month between October and November 2012. Emergency clinicians (including physicians, registrars, hospital medical officers, interns and nurse practitioners) filled out a questionnaire within 5min of obtaining a history and clinical examination for eligible patients. Predicted patient disposition (representing 'rapid disposition') was compared with final disposition (determined by 'standard assessment'). Results There were 301 patient episodes included in the study. Predicted disposition was correct in 249 (82.7%, 95% confidence interval (CI) 78.0-86.8) cases. Accuracy of predicting discharge to home appeared highest among emergency physicians at 95.8% (95% CI 78.9-99.9). Overall accuracy at predicting admission was 79.7% (95% CI 67.2-89.0). The remaining 20.3% (95% CI 11.0-32.8) were not admitted following standard assessment. Conclusion Rapid disposition by ED clinicians can predict patient destination accurately but was associated with a potential increase in admission rates. Any model of care using rapid disposition decision making should involve establishment of inpatient systems for further assessment, and a culture of timely inpatient team transfer of patients to the most appropriate treating team for ongoing patient management. What is known about the topic? In response to the National Emergency Access Targets, there has been widespread adoption of rapid-disposition-themed care models across Australia. Although there is emerging data that clinicians can predict disposition accurately, this data is currently limited. What does this

  12. Rapidly destructive osteoarthritis can mimic infection

    Directory of Open Access Journals (Sweden)

    Gavin Hart, MD

    2016-03-01

    Full Text Available The intraoperative appearance of rapidly destructive osteoarthritis and septic arthritis can be similar. Three patients at our institution demonstrated preoperative or intraoperative findings potentially consistent with infection during primary total hip arthroplasty; however, none of these patients were found to have an actual infection. One of these patients underwent an unnecessary 2-stage total hip arthroplasty secondary to the intraoperative appearance of their joint fluid. We advocate performing an infection workup preoperatively when patients present with rapid degenerative changes of their hip joint to diminish the uncertainty of proceeding with arthroplasty.

  13. Corrosion of metal samples rapidly measured

    Science.gov (United States)

    Maskell, C. E.

    1966-01-01

    Corrosion of a large number of metal samples that have been exposed to controlled environment is accurately and rapidly measured. Wire samples of the metal are embedded in clear plastic and sectioned for microexamination. Unexposed wire can be included in the matrix as a reference.

  14. Morphological Transition in Rapidly Expanding Magmas

    Science.gov (United States)

    Kolinski, J.; Chakraborty, P.; Gioia, G.; Kieffer, S. W.

    2008-12-01

    Many explosive eruptions are initiated by rapid decompression of bubbly magma, which behaves as an elastic material during the decompression and fragments into discrete pieces following the decompression. To emulate the rapid decompression of bubbly magma, we subject a two-dimensional foam of soap bubbles to quasi-static expansion. A recent theory predicts that where a two-dimensional foam of soap bubbles is first subjected to expansion, the foam expands homogeneously. After a critical value of expansion is attained, the foam undergoes a morphological transition and separates into a large number of small bubbles immersed in a background of a few large bubbles [Vainchtein and Aref, Physics of Fluids 13, 2001]. In our experiments we verify the phenomenon of morphological transition under area expansion. We verity the predictions of Vainchtein and Aref, compare our results with the experimental results on rapidly expanding bubble-bearing viscoelastic fluids reported by [Namiki and Manga, Earth and Planetary Science Letters 236, 2005], and discuss the implications of our results for the rapid decompression of magmas.

  15. Rapid resistome mapping using nanopore sequencing

    DEFF Research Database (Denmark)

    van der Helm, Eric; Imamovic, Lejla; Ellabaan, Mostafa M Hashim

    2017-01-01

    of bacterial infections. Yet, rapid workflows for resistome characterization are lacking. To address this challenge we developed the poreFUME workflow that deploys functional metagenomic selections and nanopore sequencing to resistome mapping. We demonstrate the approach by functionally characterizing the gut...

  16. Rapid Targeted Genomics in Critically Ill Newborns

    NARCIS (Netherlands)

    van Diemen, Cleo C; Kerstjens-Frederikse, Wilhelmina S; Bergman, Klasien A; de Koning, Tom J; Sikkema-Raddatz, Birgit; van der Velde, Joeri K; Abbott, Kristin M; Herkert, Johanna C; Löhner, Katharina; Rump, Patrick; Meems-Veldhuis, Martine T; Neerincx, Pieter B T; Jongbloed, Jan D H; van Ravenswaaij-Arts, Conny M; Swertz, Morris A; Sinke, Richard J; van Langen, Irene M; Wijmenga, Cisca

    2017-01-01

    BACKGROUND: Rapid diagnostic whole-genome sequencing has been explored in critically ill newborns, hoping to improve their clinical care and replace time-consuming and/ or invasive diagnostic testing. A previous retrospective study in a research setting showed promising results with diagnoses in

  17. Cognitive Predictors of Rapid Picture Naming

    Science.gov (United States)

    Decker, Scott L.; Roberts, Alycia M.; Englund, Julia A.

    2013-01-01

    Deficits in rapid automatized naming (RAN) have been found to be a sensitive cognitive marker for children with dyslexia. However, there is a lack of consensus regarding the construct validity and theoretical neuro-cognitive processes involved in RAN. Additionally, most studies investigating RAN include a narrow range of cognitive measures. The…

  18. Utilizing Information Technology to Facilitate Rapid Acquisition

    Science.gov (United States)

    2006-06-01

    ordering systems to facilitate streamlined commercial item acquisitions that reap the benefits of improved efficiency, reduced overall costs, and...PAGES 109 14. SUBJECT TERMS Rapid Acquisition, eCommerce , eProcurement, Information Technology, Contracting, Global Information Network...streamlined commercial item acquisitions that reap the benefits of improved efficiency, reduced overall costs, and timeliness. This thesis

  19. A rapidly enlarging cutaneous hemangioma in pregnancy

    Directory of Open Access Journals (Sweden)

    Marwan Ma’ayeh

    2014-10-01

    Full Text Available This is a case of a rapidly enlarging cutaneous pedunculated tumor on a patient’s thumb during her pregnancy. This was excised and identified as a hemangioma. A literature search identified a possible hormonal factor in causing an accelerated growth of this tumor.

  20. Preparation, Evaluation and Optimization of Rapidly Disintegrating ...

    African Journals Online (AJOL)

    The unit dose content uniformity, dissolution rate, assay values and other tablet characteristics evaluated were all within the acceptable limits. Thus, it was possible to formulate an RDT of artemether-lumefantrine FDC using CPVP as a disintegrant and camphor as a pore forming agent. Keywords: rapidly disintegrating tablet ...

  1. Ceramic microfabrication by rapid prototyping process chains

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    fast and inexpensive supply for polymer master models and a ceramic shaping method that enables the replication of the RP model into multiple ceramic materials within a short time. (Knitter et al 1999). 2. Rapid prototyping process chains. The manufacturing of ceramic microparts presented here set out with the 3D-CAD ...

  2. RESEARCH NOTE Rapid isolation and characterization of ...

    Indian Academy of Sciences (India)

    fraser c

    2017-10-25

    Oct 25, 2017 ... Rapid isolation and characterization of microsatellites in the critically endangered Mountain Bongo (Tragelaphus eurycerus isaaci). Authors: Fraser J Combe1, Evelyn Taylor-Cox1, Graeme Fox1, Tommy Sandri1,3, Nick Davis2, Martin J Jones1, Bradly Cain1, David. Mallon1, W Edwin Harris1*. 1. Division of ...

  3. A rapidly enlarging cutaneous hemangioma in pregnancy.

    LENUS (Irish Health Repository)

    Ma'ayeh, Marwan

    2014-06-18

    This is a case of a rapidly enlarging cutaneous pedunculated tumor on a patient\\'s thumb during her pregnancy. This was excised and identified as a hemangioma. A literature search identified a possible hormonal factor in causing an accelerated growth of this tumor.

  4. Short Communication: Rapid Visual Assessment of Fish ...

    African Journals Online (AJOL)

    Short Communication: Rapid Visual Assessment of Fish Communities on Selected Reefs in the Bazaruto Archipelago. ... the Bazaruto reef types to provide a basis for their sound management and conservation. Keywords: Bazaruto Archipelago, Mozambique, ichthyofauna, fish surveys, underwater visual census, coral reefs.

  5. Rapid response systems in The Netherlands

    NARCIS (Netherlands)

    Ludikhuize, Jeroen; Hamming, Annette; de Jonge, Evert; Fikkers, Bernard G.

    2011-01-01

    Sixty-three (approximately 80%) of the 81 hospitals that responded to a survey sent to all hospitals in The Netherlands with nonpediatric intensive care units had a rapid response system (RRS) in place or were in the final process of starting one. Among many other findings regarding RRS

  6. Rapid micropropagation of three elite Sugarcane (Saccharum ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-04

    Jul 4, 2008 ... For rapid multiplication the regenerated shoots were transferred on liquid Murashige and Skoog medium containing 2% sucrose, supplemented with. BAP in combinations with GA3. Optimum multiplication was observed at 1 mg/l BAP in combination with. 0.1 mg/l GA3 for variety HSF-240. Best response of ...

  7. Rapid micropropagation of Boesenbergia rotunda (L.) Mansf ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... A rapid multiplication method is required to supply sufficient disease-free plant material for large scale cultivation using in vitro propa- gation. In vitro propagation of Zingiberaceae has already been reported, for example Alpinia galanga (Inden and. Asahir, 1988) and Zingiber officinale (Hosoki and Sagawa,.

  8. The RapidEye mission design

    Science.gov (United States)

    Tyc, George; Tulip, John; Schulten, Daniel; Krischke, Manfred; Oxfort, Michael

    2005-01-01

    The RapidEye mission is a commercial remote sensing mission by the German Company RapidEye AG. The RapidEye mission will deliver information products for various customers in the agricultural insurance market, large producers, international institutions and cartography. The mission consists of a constellation of five identical small satellites and a sophisticated ground infrastructure based on proven systems. The five satellites will be placed in a single sun-synchronous orbit of approximately 620 km, with the satellites equally spaced over the orbit. The RapidEye system has the unique ability to image any area on earth once per day and can also provide large area coverage within 5 days. The satellites will each carry a 5 band multi-spectral optical imager with a ground sampling distance of 6.5 m at nadir and a swath width of 80 km. These capabilities along with the processing throughput of the ground segment allows the system to deliver the information products needed by the customers reliably and in a time frame that meets their specific needs.

  9. Integrating Rapid Prototyping into Graphic Communications

    Science.gov (United States)

    Xu, Renmei; Flowers, Jim

    2015-01-01

    Integrating different science, technology, engineering, and mathematics (STEM) areas can help students learn and leverage both the equipment and expertise at a single school. In comparing graphic communications classes with classes that involve rapid prototyping (RP) technologies like 3D printing, there are sufficient similarities between goals,…

  10. Rapid Energy Modeling Workflow Demonstration Project

    Science.gov (United States)

    2014-01-01

    BIM Building Information Model BLCC building life cycle costs BPA Building Performance Analysis CAD computer assisted...utilizes information on operations, geometry, orientation, weather, and materials, generating Three-Dimensional (3D) Building Information Models ( BIM ...executed a demonstration of Rapid Energy Modeling (REM) workflows that employed building information modeling ( BIM ) approaches and

  11. Rapid high performance liquid chromatographic determination of ...

    African Journals Online (AJOL)

    Rapid high performance liquid chromatographic determination of chlorpropamide in human plasma. MTB Odunola, IS Enemali, M Garba, OO Obodozie. Abstract. Samples were extracted with dichloromethane and the organic layer evaporated to dryness. The residue was dissolved in methanol, and 25 ìl aliquot injected ...

  12. Rapidly progressive post-transplant lymphoproliferative disease ...

    African Journals Online (AJOL)

    Sirolimus, a potent inhibitor of B- and T-cell activation, is a commonly used immunosuppressant after renal transplantation. Withdrawal of sirolimus from the immunosuppression regimen may reduce B-cell surveillance. We present a case of rapidly progressive central nervous system (CNS) polymorphic Epstein-Barr virus ...

  13. Diffraction and rapidity gap measurements with ATLAS

    CERN Document Server

    Kus, V; The ATLAS collaboration

    2014-01-01

    Two diffraction related measurements of proton-proton collisions in the ATLAS experiment of the Large Hadron Collider at $\\surd s$ = 7 TeV centre-of-mass energy are reviewed. First of them is a fraction of diffractive contribution to the inelastic cross section. Second measurement is dedicated to the identification of Single Diffractive interactions with large pseudo-rapidity gaps using early 2010 data sample of integrated luminosity 7.1 $\\mu b^{-1}$. Differential cross sections of largest forward areas of the ATLAS detector starting at its most forward edges $\\eta = \\pm 4.9$ without any particle activity above different transverse momentum thresholds are measured. Results are compared to several distinctive Monte Carlo models resulting in constraint of Pomeron intercept value in triple Pomeron based approach. Furthermore, proton-proton interactions in small pseudo-rapidity gap region test qualitatively a description of different hadronisation models as well as statistical fluctuations during hadronisation pr...

  14. To Internationalize Rapidly from Inception: Crowdsource

    Directory of Open Access Journals (Sweden)

    Nirosh Kannangara

    2012-10-01

    Full Text Available Technology entrepreneurs continuously search for tools to accelerate the internationalization of their startups. For the purpose of internationalizing rapidly from inception, we propose that technology startups use crowdsourcing to internalize the tacit knowledge embodied in members of a crowd distributed across various geographies. For example, a technology startup can outsource to a large crowd the definition of a customer problem that occurs across various geographies, the development of the best solution to the problem, and the identification of attractive business expansion opportunities. In this article, we analyze how three small firms use crowdsourcing, discuss the benefits of crowdsourcing, and offer six recommendations to technology entrepreneurs interested in using crowdsourcing to rapidly internationalize their startups from inception.

  15. Rapid-Cycling Bubble-Chamber, details

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Parts of the hydraulic expansion system of the Rapid-Cycling Bubble-Chamber (RCBC). RCBC was the largest of 3 rapid-cycling bubble-chambers (the others were LEBC and HOLEBC), used as target- and vertex-detectors within the European Hybrid Spectrometer (EHS) in the SPS North Area (EHN1). RCBC contained 250 l of liquid hydrogen and was located inside a 3 T superconducting magnet. It was designed for 30 expansions/s (100 times faster than BEBC), the system shown here allowed 50 expansions/s. RCBC operated from 1981 to 1983 for experiments NA21, NA22 and NA23 at a rate of 15 expansions/s, clocking up a total of over 4 million. In the rear, at left, is bearded Lucien Veillet; Augustin Didona is at the right. See also 8001009. The installation of the piston assembly in the RCBC chamber body is shown in the Annual Report 1980, p.65.

  16. Rapid quenching effects in PVC films

    Science.gov (United States)

    Lee, H. D.; Mandell, J. F.; Mcgarry, F. J.

    1981-01-01

    Using a specially constructed microbalance for hydrostatic weighing, density changes in PVC thin films (with no additives, 30-100 micrometers thick), due to rapid quenching (approximately 300 C/sec) through the glass transition temperature, have been observed. The more severe the quench, the greater is the free volume content. Isobaric volume recovery of PVC has also been studied by volume dilatometry. Both show aging of relaxing molecular rearrangements takes place as a linear function of logarithmic aging time at room temperature. Distribution of retardation times and Primak's distributed activation energy spectra have been applied to the volume recovery data. The concomitant changes in mechanical properties of PVC after quenching have been monitored by tensile creep and stress-strain to failure. All reflect the presence of excess free volume content, due to rapid quenching.

  17. Rapid parapatric speciation on holey adaptive landscapes

    CERN Document Server

    Gavrilets, S; Vose, M D; Gavrilets, Sergey; Li, Hai; Vose, Michael D.

    1998-01-01

    A classical view of speciation is that reproductive isolation arises as a by-product of genetic divergence. Here, individual-based simulations are used to evaluate whether the mechanisms implied by this view may result in rapid speciation if the only source of genetic divergence are mutation and random genetic drift. Distinctive features of the simulations are the consideration of the complete process of speciation (from initiation until completion), and of a large number of loci, which was only one order of magnitude smaller than that of bacteria. It is demonstrated that rapid speciation on the time scale of hundreds of generations is plausible without the need for extreme founder events, complete geographic isolation, the existence of distinct adaptive peaks or selection for local adaptation. The plausibility of speciation is enhanced by population subdivision. Simultaneous emergence of more than two new species from a subdivided population is highly probable. Numerical examples relevant to the theory of ce...

  18. Rapid prototyping: An innovative technique in dentistry

    Directory of Open Access Journals (Sweden)

    Shakeba Quadri

    2017-01-01

    Full Text Available Emergence of advanced digital technology has opened up new perspectives for design and production in the field of dentistry. Rapid prototyping (RP is a technique to quickly and automatically construct a three-dimensional (3D model of a part or product using 3D printers or stereolithography machines. RP has various dental applications, such as fabrication of implant surgical guides, zirconia prosthesis and molds for metal castings, maxillofacial prosthesis and frameworks for fixed and removable partial dentures, wax patterns for the dental prosthesis and complete denture. Rapid prototyping presents fascinating opportunities, but the process is difficult as it demands a high level of artistic skill, which means that the dental technicians should be able to work with the models obtained after impression to form a mirror image and achieve good esthetics. This review aims to focus on various RP methods and its application in dentistry.

  19. Rapid eye movement sleep in breath holders.

    Science.gov (United States)

    Kohyama, J; Hasegawa, T; Shimohira, M; Fukumizu, M; Iwakawa, Y

    2000-07-01

    One-night polysomnography was performed on seven subjects suffering from breath-holding spells, including one whose death was suggested to be a consequence of a breath-holding spell. The fatal case showed no rapid eye movements (REMs) during REM sleep, although he exhibited REMs during wakefulness. The average numbers of both REMs and bursts of REMs in REM sleep in the other six breath holders were significantly lower than those in age-matched controls. The breath holders showed no airway obstruction, desaturation, or sleep fragmentation. Since the rapid ocular activity in REM sleep is generated in the brain stem, we hypothesized that a functional brainstem disturbance is involved in the occurrence of breath-holding spells.

  20. Rapidly moving contact lines and damping contributions

    Science.gov (United States)

    Xia, Yi; Daniel, Susan; Steen, Paul

    2017-11-01

    Contact angle varies dynamically with contact line (CL) speed when a liquid moves across a solid support, as when a liquid spreads rapidly. For sufficiently rapid spreading, inertia competes with capillarity to influence the interface shape near the support. We use resonant-mode plane-normal support oscillations of droplets to drive lateral contact-line motion. Reynolds numbers based on CL speeds are high and capillary numbers are low. These are inertial-capillary motions. By scanning the driving frequency, we locate the frequency at peak amplification (resonance), obtain the scaled peak height (amplification factor) and a measure of band-width (damping ratio). We report how a parameter for CL mobility depends on these scanning metrics, with the goal of distinguishing contributions from the bulk- and CL-dissipation to overall damping.

  1. Organizational Design for USSOCOM Rapid Acquisition

    Science.gov (United States)

    2017-03-31

    2 Ibid., 249. 25 of the programs.3 In rapid innovation , it is important for Program Executive Officers to ensure that technical...organizational learning is what the company does in order to create innovative products and survive. They note that, “interviewees emphasized the importance ...14. ABSTRACT USSOCOM Special Operations Forces (SOF) Acquisition, Technology and Logistics (AT&L) struggles to keep pace with technology innovation

  2. Rapid determination of capsaicinoids by colorimetric method

    OpenAIRE

    Ryu, Wang-Kyun; Kim, Hee-Woong; Kim, Geun-Dong; Rhee, Hae-Ik

    2016-01-01

    Capsaicinoids, the pungent component of chili peppers, are generally analyzed by precise analytical techniques, such as gas chromatography and high-performance liquid chromatography (HPLC), but these are not practical for the mass analyses of samples. To analyze mass samples rapidly, a colorimetric method was suggested. In this work, pigments and capsaicinoids were efficiently separated from chili pepper extract by sequential solid–liquid extraction and liquid–liquid extraction in test tubes ...

  3. Rapid Set Materials for Advanced Spall Repair

    Science.gov (United States)

    2010-08-01

    compressive strength, tensile strength, modulus of rupture, and the coefficient of thermal expansion. pavement , spall repair, airfield damage repair...expediency and quality. Rapid repairs extend the life of a pavement using more forgiving methods than those used in traditional repairs, but...cement-based polymer -cement mortar and concrete • Magnesium-ammonium-phosphate-cement mortar and concrete • Polymer -based mortar and concrete

  4. Rapid Hydraulic Assessment for Stream Restoration

    Science.gov (United States)

    2016-02-01

    governing equations are often used in conjunction with each other to define the flow characteristics of a given hydraulic phenomenon. The energy equation...Approved for public release; distribution is unlimited. ERDC TN-EMRRP-SR-48 February 2016 Rapid Hydraulic Assessment for Stream Restoration...account the hydraulic conditions of the stream being restored. This is true whether the project involves a few feet of bank stabilization or several

  5. Development and tendency of rapid prototyping technology

    Science.gov (United States)

    Yan, Yongnian; Hong, Guodong

    1998-08-01

    The definition of the rapid prototyping is given in this paper. Various RP processes, which build the prototypes with 2.5 or 3 dimensional layers, are introduced. The relative techniques of RP and the differences between RP technique and CNC manufacturing are analyzed. The paper discusses the RP's applied fields and methods and presents the RP development in the world. According to the idea that requirements determine the developing, the RP's tendency is discussed.

  6. Rapid and highly fieldable viral diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Timothy E.

    2016-12-20

    The present invention relates to a rapid, highly fieldable, nearly reagentless diagnostic to identify active RNA viral replication in a live, infected cells, and more particularly in leukocytes and tissue samples (including biopsies and nasal swabs) using an array of a plurality of vertically-aligned nanostructures that impale the cells and introduce a DNA reporter construct that is expressed and amplified in the presence of active viral replication.

  7. Removable partial dentures: use of rapid prototyping.

    Science.gov (United States)

    Lima, Julia Magalhaes Costa; Anami, Lilian Costa; Araujo, Rodrigo Maximo; Pavanelli, Carlos A

    2014-10-01

    The CAD/CAM technology associated with rapid prototyping (RP) is already widely used in the fabrication of all-ceramic fixed prostheses and in the biomedical area; however, the use of this technology for the manufacture of metal frames for removable dentures is new. This work reports the results of a literature review conducted on the use of CAD/CAM and RP in the manufacture of removable partial dentures. © 2014 by the American College of Prosthodontists.

  8. Diffraction and rapidity gap measurements in ATLAS

    CERN Document Server

    Bernat, P; The ATLAS collaboration

    2012-01-01

    The early data recorded by the ATLAS detector during 2010 presents a great opportunity to study diffraction cross section in proton-proton collision. The differential cross section of diffractive dissociation is studied as a function of the maximum rapidity gap, up to 8 in rapidity units. Data are compared to different models of diffractive dynamics in standard event generators. A rise at large rapidity gaps is interpreted with a triple pomeron based approach, using Pythia 8 prediction (with a Donnachie-Landshoff model). A pomeron intercept of 1.058 ± 0.003(stat) +0.034-0.039 (syst) is found. A measurement of the dijet production with a jet veto on additional central activity using 2010 data is also presented. The use of a veto scale at 20 GeV allows to measure the jet activity in dijet events. As the veto scale is much larger than Lambda_s different QCD phenomena can be studied. Moreover, ATLAS data explores regions of the phase space for the first time. The main observable in this analysis is the fraction ...

  9. Rapidly progressive young-onset dementia.

    Science.gov (United States)

    Kelley, Brendan J; Boeve, Bradley F; Josephs, Keith A

    2009-03-01

    To characterize a cohort of individuals who have experienced rapidly progressive dementia with onset before age 45. Very little data regarding the clinical features or clinical spectrum of rapidly progressive young-onset dementia (RP-YOD) is available, primarily consisting of case reports or small series. A search of the Mayo Clinic medical record was employed to identify patients who had onset before age 45 of rapidly progressive dementia. All available medical records, laboratory data, neuroimaging studies, and pathologic data were reviewed. Twenty-two patients met the predefined inclusion and exclusion criteria. Behavioral and affective disorders, cerebellar dysfunction, and visual and/or oculomotor dysfunction were common early clinical features within the cohort, as were clinical features often associated with Creutzfeldt-Jakob disease. Diagnostic testing identified an etiology in most patients. Presentations of RP-YOD result from a variety of etiologies and significant overlap in clinical features is observed. Clinical features often associated with Creutzfeldt-Jakob disease seem to be common within the entire cohort of RP-YOD patients. Diagnostic studies aided in establishing a diagnosis in most patients, however 5 had uncertain diagnoses despite exhaustive evaluation.

  10. Rapid Prototyping and its Application in Dentistry

    Directory of Open Access Journals (Sweden)

    V. N. V. Madhav

    2013-01-01

    Full Text Available Medical implants and biological models have three main characteristics: low volume, complex shape, and can be customized. These characteristics suit very well with Rapid Prototyping (RP and Rapid Manufacturing (RM processes. RP/RM processes are fabricated part layer- by-layer until complete shape finished from 3D model. Biocompatible materials, such as Titanium and Titanium alloy, Zirconium, Cobalt Chromium, PEEK, etc, are used for fabrication process. Reverse Engineering (RE technology greatly affects RP/RM processes. RE is used to capture or scan image of the limb, cranium, tooth, and other biological objects. Three common methods to get the image are 3D laser scanning, Computer Tomography (CT, and Magnetic Resonance Imaging (MRI. Main RP/RM techniques used in Dentistry are Stereotype Lithography Apparatus (SLA, Fused Deposition Modeling (FDM, Selective Laser Sintering (SLS, and ink jet printing. This article reviews the changing scenario of technology in dentistry with special emphasis on Rapid Prototyping and its various applications in Dentistry.

  11. The genomic landscape of rapid repeated evolutionary ...

    Science.gov (United States)

    Atlantic killifish populations have rapidly adapted to normally lethal levels of pollution in four urban estuaries. Through analysis of 384 whole killifish genome sequences and comparative transcriptomics in four pairs of sensitive and tolerant populations, we identify the aryl hydrocarbon receptor–based signaling pathway as a shared target of selection. This suggests evolutionary constraint on adaptive solutions to complex toxicant mixtures at each site. However, distinct molecular variants apparently contribute to adaptive pathway modification among tolerant populations. Selection also targets other toxicity-mediatinggenes and genes of connected signaling pathways; this indicates complex tolerance phenotypes and potentially compensatory adaptations. Molecular changes are consistent with selection on standing genetic variation. In killifish, high nucleotide diversityhas likely been a crucial substrate for selective sweeps to propel rapid adaptation. This manuscript describes genomic evaluations that contribute to our understanding of the ecological and evolutionary risks associated with chronic contaminant exposures to wildlife populations. Here, we assessed genetic patterns associated with long-term response to an important class of highly toxic environmental pollutants. Specifically, chemical-specific tolerance has rapidly and repeatedly evolved in an estuarine fish species resident to estuaries of the Atlantic U.S. coast. We used laboratory studies to ch

  12. Management of Infections with Rapidly Growing

    Directory of Open Access Journals (Sweden)

    Jong Hwan Kim

    2012-01-01

    Full Text Available Background Infection caused by rapidly growing mycobacteria (RGM is not uncommon, andthe prevalence of RGM infection has been increasing. Clinical diagnosis is difficult becausethere are no characteristic clinical features. There is also no standard antibiotic regimenfor treating RGM infection. A small series of patients with RGM infections was studied toexamine their treatments and outcomes.Methods A total of 5 patients who had developed postoperative infections from January2009 to December 2010 were retrospectively reviewed. Patients were initially screened using amycobacteria rapid screening test (polymerase chain reaction [PCR]-reverse blot hybridizationassay. To confirm mycobacterial infection, specimens were cultured for nontuberculousmycobacteria and analyzed by 16 S ribosomal RNA and rpoB gene PCR.Results The patients were treated with intravenous antibiotics during hospitalization,and oral antibiotics were administered after discharge. The mean duration of follow-upwas 9 months, and all patients were completely cured of infection with a regimen of acombination of antibiotics plus surgical treatment. Although none of the patients developedrecurrence, there were complications at the site of infection, including hypertrophic scarring,pigmentation, and disfigurement.Conclusions Combination antibiotic therapy plus drainage of surgical abscesses appeared tobe effective for the RGM infections seen in our patients. Although neither the exact dosagenor a standardized regimen has been firmly established, we propose that our treatment canprovide an option for the management of rapidly growing mycobacterial infection.

  13. Rapid Column Extraction method for SoilRapid Column Extraction method for Soil

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod, L. III; Culligan, Brian K.

    2005-11-07

    The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu) neptunium (Np), uranium (U), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha spectrometry. The method combines a rapid fusion step for total dissolution to dissolve refractory analytes and matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.

  14. Rapid Response in Psychological Treatments for Binge-Eating Disorder

    Science.gov (United States)

    Hilbert, Anja; Hildebrandt, Thomas; Agras, W. Stewart; Wilfley, Denise E.; Wilson, G. Terence

    2015-01-01

    Objective Analysis of short- and long-term effects of rapid response across three different treatments for binge-eating disorder (BED). Method In a randomized clinical study comparing interpersonal psychotherapy (IPT), cognitive-behavioral guided self-help (CBTgsh), and behavioral weight loss (BWL) treatment in 205 adults meeting DSM-IV criteria for BED, the predictive value of rapid response, defined as ≥ 70% reduction in binge-eating by week four, was determined for remission from binge-eating and global eating disorder psychopathology at posttreatment, 6-, 12-, 18-, and 24-month follow-up. Results Rapid responders in CBTgsh, but not in IPT or BWL, showed significantly greater rates of remission from binge-eating than non-rapid responders, which was sustained over the long term. Rapid and non-rapid responders in IPT and rapid responders in CBTgsh showed a greater remission from binge-eating than non-rapid responders in CBTgsh and BWL. Rapid responders in CBTgsh showed greater remission from binge-eating than rapid responders in BWL. Although rapid responders in all treatments had lower global eating disorder psychopathology than non-rapid responders in the short term, rapid responders in CBTgsh and IPT were more improved than those in BWL and non-rapid responders in each treatment. Rapid responders in BWL did not differ from non-rapid responders in CBTgsh and IPT. Conclusions Rapid response is a treatment-specific positive prognostic indicator of sustained remission from binge-eating in CBTgsh. Regarding an evidence-based stepped care model, IPT, equally efficacious for rapid and non-rapid responders, could be investigated as a second-line treatment in case of non-rapid response to first-line CBTgsh. PMID:25867446

  15. Rapidly progressive periodontitis. A distinct clinical condition.

    Science.gov (United States)

    Page, R C; Altman, L C; Ebersole, J L; Vandesteen, G E; Dahlberg, W H; Williams, B L; Osterberg, S K

    1983-04-01

    We report radiographic, clinical, historical, and laboratory observations on seven patients selected to illustrate the features and characteristics of rapidly progressive periodontitis, with the aim of establishing this disease as a distinct clinical entity. This form of periodontitis is seen most commonly in young adults in their twenties, but it can occur in postpubertal individuals up to approximately 35 years of age. During the active phase, the gingival tissues are extremely inflamed and there is hemorrhage, proliferation of the marginal gingiva, and exudation. Destruction is very rapid, with loss of much of the alveolar bone occurring within a few weeks or months. This phase may be accompanied by general malaise, weight loss, and depression, although these symptoms are not seen in all patients. The disease may progress, without remission, to tooth loss, or alternatively, it may subside and become quiescent with or without therapy. The quiescent phase is characterized by the presence of clinically normal gingiva that may be tightly adapted to the roots of teeth with very advanced bone loss and deep periodontal pockets. The quiescent phase may be permanent, it may persist for an indefinite period, or the disease activity may return. Most patients with rapidly progressive periodontitis have serum antibodies specific for various species of Bacteroides, Actinobacillus, or both, and manifest defects in either neutrophil or monocyte chemotaxis. Affected patients generally respond favorably to treatment by scaling and open or closed curettage, especially when accompanied by standard doses of antibiotics for conventional time periods. A small minority of patients do not respond to any treatment, including antibiotics, and the disease progresses inexorably to tooth loss even in the presence of aggressive periodontal therapy and maintenance. At the present time it is not possible to distinguish prior to treatment which individuals will respond to therapy and which will

  16. Intraperitoneal Glucose Sensing is Sometimes Surprisingly Rapid

    Directory of Open Access Journals (Sweden)

    Anders Lyngvi Fougner

    2016-04-01

    Full Text Available Rapid, accurate and robust glucose measurements are needed to make a safe artificial pancreas for the treatment of diabetes mellitus type 1 and 2. The present gold standard of continuous glucose sensing, subcutaneous (SC glucose sensing, has been claimed to have slow response and poor robustness towards local tissue changes such as mechanical pressure, temperature changes, etc. The present study aimed at quantifying glucose dynamics from central circulation to intraperitoneal (IP sensor sites, as an alternative to the SC location. Intraarterial (IA and IP sensors were tested in three anaesthetized non-diabetic pigs during experiments with intravenous infusion of glucose boluses, enforcing rapid glucose level excursions in the range 70--360 mg/dL (approximately 3.8--20 mmol/L. Optical interferometric sensors were used for IA and IP measurements. A first-order dynamic model with time delay was fitted to the data after compensating for sensor dynamics. Additionally, off-the-shelf Medtronic Enlite sensors were used for illustration of SC glucose sensing. The time delay in glucose excursions from central circulation (IA to IP sensor location was found to be in the range 0--26 s (median: 8.5 s, mean: 9.7 s, SD 9.5 s, and the time constant was found to be 0.5--10.2 min (median: 4.8 min, mean: 4.7 min, SD 2.9 min. IP glucose sensing sites have a substantially faster and more distinctive response than SC sites when sensor dynamics is ignored, and the peritoneal fluid reacts even faster to changes in intravascular glucose levels than reported in previous animal studies. This study may provide a benchmark for future, rapid IP glucose sensors.

  17. Rapid response manufacturing (RRM). Final CRADA report

    Energy Technology Data Exchange (ETDEWEB)

    Cain, W.D. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States); Waddell, W.L. [National Centers for Manufacturing Sciences, Ann Arbor, MI (United States)

    1998-02-10

    US industry is fighting to maintain its competitive edge in the global market place. Markets fluctuate rapidly. Companies have to be able to respond quickly with improved, high quality, cost efficient products. Because companies and their suppliers are geographically distributed, rapid product realization is dependent on the development of a secure integrated concurrent engineering environment operating across multiple business entities. The way products are developed and brought to market can be improved and made more efficient through the proper incorporation of emerging technologies implemented in a secure environment. This documents the work done under this CRADA to develop capabilities, which permit the effective application, incorporation, and use of advanced technologies in a secure environment to facilitate the product realization process. Lockheed Martin Energy Systems (LMES), through a CRADA with the National Center for Manufacturing Sciences (NCMS), worked within a consortium of major industrial firms--Ford, General Motors, Texas Instruments, United Technologies, and Eastman Kodak--and several small suppliers of advanced manufacturing technology--MacNeal-Schwendler Corp., Teknowledge Corp., Cimplex Corp., Concentra, Spatial Technology, and Structural Dynamics Research Corp. (SDRC)--to create infrastructure to support the development and implementation of secure engineering environments for Rapid Response Manufacturing. The major accomplishment achieved under this CRADA was the demonstration of a prototypical implementation of a broad-based generic framework for automating and integrating the design-to-manufacturing activities associated with machined parts in a secure NWC compliant environment. Specifically, methods needed to permit the effective application, incorporation, and use of advanced technologies in a secure environment to facilitate the product realization process were developed and demonstrated. An important aspect of this demonstration was

  18. Rapid visual colorimetry of peritoneal lavage fluid.

    Science.gov (United States)

    Tandberg, D; Reitmeyer, S T; Cheney, P R

    1990-11-01

    That visual colorimetry can be used to rapidly and precisely estimate the erythrocyte count of 1:5 dilutions of simulated peritoneal lavage fluid. Fifty-four normal adult human subjects. The automated or chamber RBC count is often used on fluid obtained by peritoneal lavage in patients with abdominal trauma to help determine the need for surgery. Unfortunately, this method sometimes results in excessive delay. We designed and built a simple colorimeter that facilitated rapid direct visual comparison of unknown samples with known color standards. A radiograph view box was used as a light source. Standards were prepared in 16-mm glass tubes to simulate peritoneal lavage fluid with RBC counts ranging from 0 to 140,000 in 10,000 cell/microL increments; 1:5 dilutions with water were used throughout to reduce opacity. Thimerosal was added to unknowns and standards to stabilize color; all samples were kept refrigerated at 4 C when not in use. In a double-blind in-vitro study, each subject matched 20 randomly distributed unknowns ranging from 12,000 to 131,000 erythrocytes/microL to the nearest standard. The mean absolute error for all 1,080 determinations was 3,560 RBC/microL (95% CI = 4,290-4,830; SD = 4,560; t = 39.6; df = 1,079; P less than .001). This method correctly predicted the RBC count to within 9,000 cells/microL 95% of the time. Visual comparison of 1:5 dilutions of simulated peritoneal lavage fluid with known color standards can be used to rapidly and precisely estimate the erythrocyte count.

  19. Sheet metal forming using rapid prototyped tooling

    Science.gov (United States)

    Park, Young-Bin

    The demand for rapid, low-cost die fabrication and modification technology is greater than ever in sheet metal forming industry. One category of rapid tooling technology involves the application of advanced polymers and composites to fabricate metal forming dies. Despite their advantages in lead time and cost reductions, polymer dies for sheet metal forming applications have several drawbacks. Due to their lack of strength as compared to conventional die materials, the use of polymer dies is often limited to prototype or short-run production. In addition, because the mechanisms by which they fail are not fully understood, the dies are designed on the basis of experience and intuition. The research (1) characterized the mechanical behavior of an advanced polymer composite tooling material, (2) developed a method to predict the failure mode and the life of a polymer die, and (3) established optimal die design guidelines. The focus was on rapid prototyped, aluminum trihydrate(ATH)-filled, polyurethane-based dies in sheet metal forming. The study involved the determination of dominant process parameters based on the finite element analyses of 90° V-die bending and cylindrical cup drawing processes. The effects of process parameters on stress distribution in the die provided guidelines to the modification of die design for achieving the desired die life. The presented parametric study lays the groundwork for providing reliable tool failure prediction and design optimization guidelines for advanced polymer tooling materials in metal forming. In addition, the failure mechanisms were investigated to predict the failure mode and the fatigue life of the die. To establish a fundamental understanding of the fatigue behavior of the polyurethane-based die material, extensive material tests were performed, the microstructure was studied, and the fatigue properties were identified experimentally. The test data were incorporated into the local stress-based fatigue analysis to

  20. CFD Script for Rapid TPS Damage Assessment

    Science.gov (United States)

    McCloud, Peter

    2013-01-01

    This grid generation script creates unstructured CFD grids for rapid thermal protection system (TPS) damage aeroheating assessments. The existing manual solution is cumbersome, open to errors, and slow. The invention takes a large-scale geometry grid and its large-scale CFD solution, and creates a unstructured patch grid that models the TPS damage. The flow field boundary condition for the patch grid is then interpolated from the large-scale CFD solution. It speeds up the generation of CFD grids and solutions in the modeling of TPS damages and their aeroheating assessment. This process was successfully utilized during STS-134.