WorldWideScience

Sample records for surface-coated cermet cutting

  1. Surface coating metrology of carbides of cutting tools

    Science.gov (United States)

    Parfenov, V. D.; Basova, G. D.

    2017-10-01

    The coatings were studied by their main sign of the micrometric thickness by means of coating destruction and electron microscopical study of cleavage surfaces. Shock stress ruptures of heated carbides of cutting tools were performed. The discovery of the coating technology and creation of the coating structure for nonuniform and nonequilibrium conditions of the cutting process were dealt with. Multifracture microdestruction of nitride coatings, caused by complex external influences, was analysed to reveal the mechanism of interaction of elementary failures. Positive results were obtained in the form of improving the strength and wear resistance of the product, crack resistance increasing.

  2. Microstructural changes during wear by plastic deformation of cemented carbide and cermet cutting inserts

    Science.gov (United States)

    Östberg, Gustaf; Andrén, Hans-Olof

    2006-05-01

    The microstructure of one WC-Co and two Ti(C,N)-WC-Co cutting inserts has been studied before and after plastic deformation, caused by high-speed turning. It was found that after deformation, the binder phase had infiltrated some of the grain boundaries and formed lamellae between the hard phase grains. The infiltration of grain boundaries was assumed to occur by a stress-induced dissolution along the grain boundaries of the hard phase grains as a wide front of binder phase, rather than gradually by Co grain boundary diffusion. Some localized dissolution of the hard phase could also be seen as faceting of grains in WC-Co and at triple points in cermets. It was concluded that the plastic deformation occurs by grain boundary infiltration with simultaneous grain boundary sliding. The rate of deformation is controlled by grain boundary infiltration through dissolution of the hard phase grains.

  3. Nature Inspired Surface Coatings

    Science.gov (United States)

    Rubner, Michael

    2011-04-01

    Materials Scientists more and more are looking to nature for clues on how to create highly functional surface coatings with exceptional properties. The fog harvesting capabilities of the Namib Desert beetle, the beautiful iridescent colors of the hummingbird, and the super water repellant abilities of the Lotus leaf are but a few examples of the amazing properties developed over many years in the natural world. Nature also makes extensive use of the pH-dependent behavior of weak functional groups such as carboxylic acid and amine functional groups. This presentation will explore synthetic mimics to the nano- and microstructures responsible for these fascinating properties. For example, we have demonstrated a pH-induced porosity transition that can be used to create porous films with pore sizes that are tunable from the nanometer scale to the multiple micron scale. The pores of these films, either nano- or micropores, can be reversibly opened and closed by changes in solution pH. The ability to engineer pH-gated porosity transitions in heterostructured thin films has led to the demonstration of broadband anti-reflection coatings that mimic the anti-reflection properties of the moth eye and pH-tunable Bragg reflectors with a structure and function similar to that found in hummingbird wings and the Longhorn beetle. In addition, the highly textured honeycomb-like surfaces created by the formation of micron-scale pores are ideally suited for the creation of superhydrophobic surfaces that mimic the behavior of the self-cleaning lotus leaf. The development of synthetic "backbacks" on immune system cells that may one day ferry drugs to disease sites will also be discussed.

  4. Cermet fuel reactors

    International Nuclear Information System (INIS)

    Cowan, C.L.; Palmer, R.S.; Van Hoomissen, J.E.; Bhattacharyya, S.K.; Barner, J.O.

    1987-09-01

    Cermet fueled nuclear reactors are attractive candidates for high performance space power systems. The cermet fuel consists of tungsten-urania hexagonal fuel blocks characterized by high strength at elevated temperatures, a high thermal conductivity and resultant high thermal shock resistance. Key features of the cermet fueled reactor design are (1) the ability to achieve very high coolant exit temperatures, and (2) thermal shock resistance during rapid power changes, and (3) two barriers to fission product release - the cermet matrix and the fuel element cladding. Additionally, thre is a potential for achieving a long operating life because of (1) the neutronic insensitivity of the fast-spectrum core to the buildup of fission products and (2) the utilization of a high strength refractory metal matrix and structural materials. These materials also provide resistance against compression forces that potentially might compact and/or reconfigure the core. In addition, the neutronic properties of the refractory materials assure that the reactor remains substantially subcritical under conditions of water immersion. It is concluded that cermet fueled reactors can be utilized to meet the power requirements for a broad range of advanced space applications. 4 refs., 4 figs., 3 tabs

  5. Direct metal brazing to cermet feedthroughs

    Science.gov (United States)

    Not Available

    1982-07-29

    An improved method for brazing metallic components to a cermet surface in an alumina substrate eliminates the prior art metallized layer over the cermet via and adjoining alumina surfaces. Instead, a nickel layer is applied over the cermet surface only and metallic components are brazed directly to this nickel coated cermet surface. As a result, heretofore unachievable tensile strength joints are produced. In addition, cermet vias with their brazed metal components can be spaced more closely in the alumina substrate because of the elimination of the prior art metallized alumina surfaces.

  6. Surface Coating of Plastic Parts for Business Machines (Industrial Surface Coating): New Source Performance Standards (NSPS)

    Science.gov (United States)

    Learn more about the new source performance standards (NSPS) for surface coating of plastic parts for business machines by reading the rule summary and history and finding the code of federal regulations as well as related rules.

  7. Investigation on hole manufacture in 42CrMo4 steel using 3-flute carbide drills and 6-flute cermet reamers

    DEFF Research Database (Denmark)

    Müller, Pavel; De Chiffre, Leonardo

    2009-01-01

    An investigation on cutting forces and hole quality using carbide 3-flute self-centering drills and 6-flute cermet reamers was performed on 42CrMo4 alloy steel. Different depths of cuts were analyzed with respect to cutting thrust and cutting torque, hole diameter, form and surface integrity. Goo...

  8. Surface properties of copper based cermet materials

    International Nuclear Information System (INIS)

    Voinea, M.; Vladuta, C.; Bogatu, C.; Duta, A.

    2008-01-01

    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO x cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO x was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components

  9. Surface properties of copper based cermet materials

    Energy Technology Data Exchange (ETDEWEB)

    Voinea, M. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)], E-mail: m.voinea@unitbv.ro; Vladuta, C.; Bogatu, C.; Duta, A. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)

    2008-08-25

    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO{sub x} cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO{sub x} was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components.

  10. Surface coating for prevention of crust formation

    Energy Technology Data Exchange (ETDEWEB)

    Kronberg, J.W.

    1994-05-24

    A flexible surface coating which promotes the removal of deposits as they reach the surface by preventing adhesion and crust formation is disclosed. Flexible layers are attached to each side of a flexible mesh substrate comprising of a plurality of zones composed of one or more neighboring cells, each zone having a different compressibility than its adjacent zones. The substrate is composed of a mesh made of strands and open cells. The cells may be filled with foam. Studs or bearings may also be positioned in the cells to increase the variation in compressibility and thus the degree of flexing of the coating. Surface loading produces varying amounts of compression from point to point causing the coating to flex as deposits reach it, breaking up any hardening deposits before a continuous crust forms. Preferably one or more additional layers are also used, such as an outer layer of a non-stick material such as TEFLON, which may be pigmented, and an inner, adhesive layer to facilitate applying the coating to a surface. 5 figs.

  11. High level waste fixation in cermet form

    International Nuclear Information System (INIS)

    Kobisk, E.H.; Aaron, W.S.; Quinby, T.C.; Ramey, D.W.

    1981-01-01

    Commercial and defense high level waste fixation in cermet form is being studied by personnel of the Isotopes Research Materials Laboratory, Solid State Division (ORNL). As a corollary to earlier research and development in forming high density ceramic and cermet rods, disks, and other shapes using separated isotopes, similar chemical and physical processing methods have been applied to synthetic and real waste fixation. Generally, experimental products resulting from this approach have shown physical and chemical characteristics which are deemed suitable for long-term storage, shipping, corrosive environments, high temperature environments, high waste loading, decay heat dissipation, and radiation damage. Although leach tests are not conclusive, what little comparative data are available show cermet to withstand hydrothermal conditions in water and brine solutions. The Soxhlet leach test, using radioactive cesium as a tracer, showed that leaching of cermet was about X100 less than that of 78 to 68 glass. Using essentially uncooled, untreated waste, cermet fixation was found to accommodate up to 75% waste loading and yet, because of its high thermal conductivity, a monolith of 0.6 m diameter and 3.3 m-length would have only a maximum centerline temperature of 29 K above the ambient value

  12. Molybdenum-base cermet fuel development

    International Nuclear Information System (INIS)

    Gurwell, W.E.; Moss, R.W.; Pilger, J.P.; White, G.D.

    1987-07-01

    Development of a multimegawatt (MMW) space nuclear power system requires identification and resolution of several technical feasibility issues before selecting one or more promising system concepts. Demonstration of reactor fuel fabrication technology is required for cermet-fueled reactor concepts. MMW reactor fuel development activity at Pacific Northwest Laboratory (PNL) is focused on producing a molybdenum-matrix uranium-nitride (UN) fueled cermet. This cermet is to have a high matrix density (≥95%) for high strength and high thermal conductance coupled with a high particle (UN) porosity (∼25%) for retention of released fission gas at high burnup. Fabrication process development involves the use of porous TiN microspheres as surrogate fuel material until porous UN microspheres become available. Process development has been conducted in the areas of microsphere synthesis, particle sealing/coating, and high-energy-rate forming (HERF) and vacuum hot press consolidation techniques. This paper summarizes the status of these activities

  13. Cermet coatings for solar Stirling space power

    International Nuclear Information System (INIS)

    Jaworske, Donald A.; Raack, Taylor

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic, are being considered for the heat inlet surface of a solar Stirling space power convertor. The role of the cermet coating is to absorb as much of the incident solar energy as possible. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition and the solar absorptance of these coatings. Several candidate cermet coatings were created and their solar absorptance was characterized as-manufactured and after exposure to elevated temperatures. Coating composition was purposely varied through the thickness of the coating. As a consequence of changing composition, islands of metal are thought to form in the ceramic matrix. Computer modeling indicated that diffusion of the metal atoms played an important role in island formation while the ceramic was important in locking the islands in place. Much of the solar spectrum is absorbed as it passes through this labyrinth

  14. Toughening behavior in ceramics and cermets

    Energy Technology Data Exchange (ETDEWEB)

    Becher, P.F.; Sun, E.Y.; Hsueh, C.H.; Plucknett, K.P. [Oak Ridge National Lab., TN (United States); Kim, H.D. [Korea Inst. of Machinery and Metals, Changwon (Korea, Republic of); Hirao, K.; Brito, M.E. [Nagoya Industrial Science Research Inst. (Japan)

    1999-03-01

    The development of high strength ({>=}1 GPa), high toughness ({>=}10 MPa{radical}(m)) ceramic systems is being examined using two approaches. In silicon nitride, toughening is achieved by the introduction of large prismatic shaped grains dispersed in a fine grain matrix. For the system examined herein, both the microstructure and the composition must be controlled. A distinctly bimodal distribution of grain diameters combined with controlled yttria to alumina ratio in additives to promote interfacial debonding is required. Using a cermet approach, ductile Ni{sub 3}Al-bonded TiC exhibited toughening due to plastic deformation within the Ni{sub 3}Al binder phase assisted by interfacial debonding and cleavage of TiC grains. The TiC-Ni{sub 3}Al cermets have toughness values equal to those of the WC-Co cermets. Furthermore, the TiC-Ni{sub 3}Al cermets exhibit high strengths that are retained in air to temperatures of {proportional_to}1000 C. (orig.) 17 refs.

  15. Toughening behavior in ceramics and cermets

    Energy Technology Data Exchange (ETDEWEB)

    Becher, P.F.; Sun, E.Y.; Hsueh, C.H.; Plucknett, K.P. [Oak Ridge National Lab., TN (United States); Kim, H.D. [Korean Inst. of Machinery and Materials, Changwon (Korea, Republic of); Hirao, K.; Brito, M. [National Industrial Research Inst., Nagoya (Japan)

    1998-10-01

    The development of high strength ({ge} 1 GPa), high toughness ({ge} 10 MPa {radical}m) ceramic systems is being examined using two approaches. In silicon nitride, toughening is achieved by the introduction of large prismatic shaped grains dispersed in a fine grain matrix. For the system examined herein, both the microstructure and the composition must be controlled. A distinctly bimodal distribution of grain diameters combined with controlled yttria to alumina ratio in additives to promote interfacial debonding is required. Using a cermet approach, ductile Ni{sub 3}Al-bonded TiC exhibited toughening due to plastic deformation within the Ni{sub 3}Al binder phase assisted by interfacial debonding and cleavage of TiC grains. The TiC-Ni{sub 3}Al cermets have toughness values equal to those of the WC-Co cermets. Furthermore, the TiC-Ni{sub 3}Al cermets exhibit high strengths that are retained in air to temperatures of {approximately} 1,000 C.

  16. Quantitation of Surface Coating on Nanoparticles Using Thermogravimetric Analysis.

    Science.gov (United States)

    Dongargaonkar, Alpana A; Clogston, Jeffrey D

    2018-01-01

    Nanoparticles are critical components in nanomedicine and nanotherapeutic applications. Some nanoparticles, such as metallic nanoparticles, consist of a surface coating or surface modification to aid in its dispersion and stability. This surface coating may affect the behavior of nanoparticles in a biological environment, thus it is important to measure. Thermogravimetric analysis (TGA) can be used to determine the amount of coating on the surface of the nanoparticle. TGA experiments run under inert atmosphere can also be used to determine residual metal content present in the sample. In this chapter, the TGA technique and experimental method are described.

  17. Performance of waterborne acrylic surface coatings on wood ...

    Indian Academy of Sciences (India)

    1, February 2011, pp. 113–119. c Indian Academy of Sciences. Performance of waterborne acrylic surface coatings on wood impregnated with Cu-ethanolamine preservatives. M HUMAR, M PAVLI ˇC, D ŽLINDRA†, M TOMAŽI ˇC†† and M PETRI ˇC. ∗. Department of Wood Science and Technology, University of Ljubljana, ...

  18. Current Developments in Antimicrobial Surface Coatings for Biomedical Applications

    NARCIS (Netherlands)

    Swartjes, J. J. T. M.; Sharma, P. K.; van Kooten, T. G.; van der Mei, H. C.; Mahmoudi, M.; Busscher, H. J.; Rochford, E. T. J.

    2015-01-01

    Bacterial adhesion and subsequent biofilm formation on material surfaces represent a serious problem in society from both an economical and health perspective. Surface coating approaches to prevent bacterial adhesion and biofilm formation are of increased importance due to the increasing prevalence

  19. Development and characterization of cermet forms for radioactive waste

    International Nuclear Information System (INIS)

    Aaron, W.S.; Quinby, T.C.; Kobisk, E.H.

    1979-01-01

    Cermets designed to isolate high-level wastes in a solid form are a composite consisting of various ceramic phase particles uniformly dispersed in and microencapsulated by an iron-nickel base alloy matrix. The metal matrix provides this waste form with many advantageous features including excellent thermal conductivity and mechanical strength. These cermets are formed by first dissolving the waste in molten urea, precipitating and calcining all the constituents, compacting the calcine, and sintering and reduction to form the final product. The exact formulation of cermets through additions to the waste is designed to fix most of the fission products in stable, leach resistant ceramic phases which are subsequently microencapsulated by an alloy matrix. The alloy matrix, which is derived primarily from the waste itself and includes the reducible fission and activation products from the waste, can be compositionally adjusted through additions to optimize its corrosion resistance under conditions existing in various disposal environments. The processes by which cermets are formed include several new and unique materials preparation options that are being developed to permit engineering scale-up and to be compatible with remote operations. Cermets formed by alternate processing methods are being characterized. Initially, cermet samples were prepared using a laboratory scale, batch process developed for the preparation of special ceramics having high compositional uniformity and excellent sinterability. The modification of this batch process to one suitable for scale-up and remote operation is the subject of this paper. Cermet characterization is also discussed

  20. LANTHANUM STAINING OF THE SURFACE COAT OF CELLS

    Science.gov (United States)

    Shea, Stephen M.

    1971-01-01

    Among the techniques which have been reported to stain the surface coat of cells, for electron microscopy, is lanthanum staining en bloc. Similarly, the presence of the cationic dye, Alcian blue 8GX, in a primary glutaraldehyde fixative has been reported to improve the preservation of the surface coat of cells of many types; however, the preserved coat is not very electron opaque unless thin sections are counterstained. The present paper shows that for several rat tissues lanthanum staining en bloc is an effective electron stain for the cell surface, giving excellent contrast, if combined sequentially with prefixation in an aldehyde fixative containing Alcian blue. The cationic substance cetylpyridinium chloride was found to have a similar effect to that of Alcian blue in enhancing the lanthanum staining of the surface coat material of the brush border of intestinal epithelial cells. The patterns of lanthanum staining obtained for the tissues studied strikingly resemble those reported in the literature where tissues are stained by several standard methods for demonstrating mucosubstances at the ultrastructural level. This fact and the reproduction of the effect of Alcian blue by cetylpyridinium chloride constitute a persuasive empirical argument that the material visualized is a mucopolysaccharide or mucopolysaccharide-protein complex. PMID:4108476

  1. Fabrication of cermet fuel for fast reactor

    International Nuclear Information System (INIS)

    Mishra, Sudhir; Kumar, Arun; Kutty, T.R.G.; Kamath, H.S.

    2011-01-01

    Mixed oxide (MOX) (U,Pu)O 2 , and metallic (U,Pu ,Zr) fuels are considered promising fuels for the fast reactor. The fuel cycle of MOX is well established. The advantages of the oxide fuel are its easy fabricability, good performance in the reactor and a well established reprocessing technology. However the problems lie in low thermal conductivity , low density of the fuel leading to low breeding ratio and consequently longer doubling time. The metallic fuel has the advantages of high thermal conductivity, higher metal density and higher coefficient of linear expansion. The higher coefficient of linear expansion is good from the safety consideration (negative reactivity factor). Because of higher metal density it offers highest breeding ratio and shortest doubling time. Metallic fuel disadvantages comprise large swelling at high burnup, fuel cladding interaction and lower margin between operating and melting temperature. The optimal solution may lie in cermet fuel (U, PuO 2 ), where PuO 2 is dispersed in U metal matrix and combines the favorable features of both the fuel types. The advantages of this fuel include high thermal conductivity, larger margin between melting and operating temperature, ability to retain fission product etc. The matrix being of high density metal the advantage of high breeding ratio is also maintained. In this report some results of fabrication of cermet pellet comprising of UO 2 /PuO 2 dispersed in U metal powder through classical powder metallurgy route and characterization are presented. (author)

  2. Mechanical behaviour of U3O8-Al cermets

    International Nuclear Information System (INIS)

    Figueredo, A.M. de; Ferreira, I.

    1981-01-01

    Homogeneous, high density U 3 O 8 -Al cermets, containing between 5 W% and 55 Wt% of U 3 ω 8 were fabricated using hot swaging and powder metallurgy technics. Tensile tests were performed at room temperature on specimens obtained from the cermets fabricated. The results show that the ultimate tensile strength (UTS) and elongation to fracture decrease with increasing U 3 O 8 in the cermet. The UTS is shown to be proportional to the minimum matrix load bearing cross-sectional area. The main influence of an increase in the content of U 3 O 8 in the cermet appears to be the decrease in the minimum matrix, load bearing cross-section. (Author) [pt

  3. Current Developments in Antimicrobial Surface Coatings for Biomedical Applications.

    Science.gov (United States)

    Swartjes, J J T M; Sharma, P K; van Kooten, T G; van der Mei, H C; Mahmoudi, M; Busscher, H J; Rochford, E T J

    2015-01-01

    Bacterial adhesion and subsequent biofilm formation on material surfaces represent a serious problem in society from both an economical and health perspective. Surface coating approaches to prevent bacterial adhesion and biofilm formation are of increased importance due to the increasing prevalence of antibiotic resistant bacterial strains. Effective antimicrobial surface coatings can be based on an anti-adhesive principle that prevents bacteria to adhere, or on bactericidal strategies, killing organisms either before or after contact is made with the surface. Many strategies, however, implement a multifunctional approach that incorporates both of these mechanisms. For anti-adhesive strategies, the use of polymer chains, or hydrogels is preferred, although recently a new class of super-hydrophobic surfaces has been described which demonstrate improved anti-adhesive activity. In addition, bacterial killing can be achieved using antimicrobial peptides, antibiotics, chitosan or enzymes directly bound, tethered through spacer-molecules or encased in biodegradable matrices, nanoparticles and quaternary ammonium compounds. Notwithstanding the ubiquitous nature of the problem of microbial colonization of material surfaces, this review focuses on the recent developments in antimicrobial surface coatings with respect to biomaterial implants and devices. In this biomedical arena, to rank the different coating strategies in order of increasing efficacy is impossible, since this depends on the clinical application aimed for and whether expectations are short- or long term. Considering that the era of antibiotics to control infectious biofilms will eventually come to an end, the future for biofilm control on biomaterial implants and devices is likely with surface-associated modifications that are non-antibiotic related.

  4. Cobalt Porphyrin-Polypyridyl Surface Coatings for Photoelectrosynthetic Hydrogen Production.

    Science.gov (United States)

    Beiler, A M; Khusnutdinova, D; Wadsworth, B L; Moore, G F

    2017-10-16

    Hybrid materials that link light capture and conversion technologies with the ability to drive reductive chemical transformations are attractive as components in photoelectrosynthetic cells. We show that thin-film polypyridine surface coatings provide a molecular interface to assemble cobalt porphyrin catalysts for hydrogen evolution onto a visible-light-absorbing p-type gallium phosphide semiconductor. Spectroscopic techniques, including grazing angle attenuated total reflection Fourier transform infrared spectroscopy, confirm that the cobalt centers of the porphyrin macrocycles coordinate to pyridyl nitrogen sites of the organic surface coating. The cobalt porphyrin surface concentration and fraction of pyridyl sites coordinated to a cobalt center are quantified using complementary methods of ellipsometry, inductively coupled plasma mass spectrometry, and X-ray photoelectron spectroscopy. In aqueous solutions under simulated solar illumination the modified cathode is photochemically active for hydrogen production, generating the product gas with near-unity Faradaic efficiency at a rate of ≈10 μL min -1 cm -2 when studied in a three-electrode configuration and polarized at the equilibrium potential of the H + /H 2 couple. This equates to a photoelectrochemical hydrogen evolution reaction activity of 17.6 H 2 molecules s -1 Co -1 , the highest value reported to date for a molecular-modified semiconductor. Key features of the functionalized photocathode include (1) the relative ease of synthetic preparation made possible by application of an organic surface coating that provides molecular recognition sites for immobilizing the cobalt porphyrin complexes at the semiconductor surface and (2) the use of visible light to drive cathodic fuel-forming reactions in aqueous solutions with no added organic acids or sacrificial chemical reductants.

  5. Inhibition of Sulfide Mineral Oxidation by Surface Coating Agents: Batch

    Science.gov (United States)

    Choi, J.; Ji, M. K.; Yun, H. S.; Park, Y. T.; Gee, E. D.; Lee, W. R.; Jeon, B.-H.

    2012-04-01

    Mining activities and mineral industries have impacted on rapid oxidation of sulfide minerals such as pyrite (FeS2) which leads to Acid Mine Drainage (AMD) formation. Some of the abandoned mines discharge polluted water without proper environmental remediation treatments, largely because of financial constraints in treating AMD. Magnitude of the problem is considerable, especially in countries with a long history of mining. As metal sulfides become oxidized during mining activities, the aqueous environment becomes acid and rich in many metals, including iron, lead, mercury, arsenic and many others. The toxic heavy metals are responsible for the environmental deterioration of stream, groundwater and soils. Several strategies to remediate AMD contaminated sites have been proposed. Among the source inhibition and prevention technologies, microencapsulation (coating) has been considered as a promising technology. The encapsulation is based on inhibition of O2 diffusion by surface coating agent and is expected to control the oxidation of pyrite for a long time. Potential of several surface coating agents for preventing oxidation of metal sulfide minerals from both Young-Dong coal mine and Il-Gwang gold mine were examined by conducting batch experiments and field tests. Powdered pyrite as a standard sulfide mineral and rock samples from two mine outcrops were mixed with six coating agents (KH2PO4, MgO and KMnO4 as chemical agents, and apatite, cement and manganite as mineral agents) and incubated with oxidizing agents (H2O2 or NaClO). Batch experiments with Young-Dong coal mine samples showed least SO42- production in presence of KMnO4 (16% sulfate production compared to no surface coating agents) or cement (4%) within 8 days. In the case of Il-Gwang mine samples, least SO42- production was observed in presence of KH2PO4 (8%) or cement (2%) within 8 days. Field-scale pilot tests at Il-Gwang site also showed that addition of KH2PO4 decreased sulfate production from 200 to

  6. Erosion behavior of EEDS cermet coatings

    International Nuclear Information System (INIS)

    Jin Guo; Xu Binshi; Wang Haidou; Yin Liang; Li Qingfen; Wei Shicheng; Cui Xiufang

    2008-01-01

    This paper investigates the erosion performance of electro-thermal explosion directional spraying (EEDS) cermet WC/Co coatings using an air solid particle erosion rig. The influences of the different parameters such as impact angle, impingement velocity, environment temperature, particle diameter, on the erosion property of the coatings were studied. The eroded surfaces were examined by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS) and the erosion mechanisms were discussed. The structure and bond characters of the coatings were also determined by transmission electron microscopy (TEM), X-ray diffraction (XRD) and SEM. The results indicate that the EEDS WC/Co coatings are characterized by fine grain structure, good metallurgical bond and brittle erosion character. The erosion rates of the coatings decrease with temperature increasing and increase with impact angle and impingement velocity increasing. At elevated temperature, the oxidation happens on the coatings surface, which affects the erosion behavior

  7. Fabrication of advanced design (grooved) cermet anodes

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.F. Jr. [Pacific Northwest Lab., Richland, WA (United States); Huettig, F.R. [Ceramic Magnetics, Inc., Fairfield, NJ (United States)

    1993-05-01

    Attempts were made to fabricate full-size anodes with advanced, or grooved, design using isostatic pressing, slip casting injection molding. Of the three approaches, isostatic pressing produced an anode with dimensions nearest to the target specifications, without serious macroscopic flaws. This approach is considered the most promising for making advanced anodes for aluminum smelting. However, significant work still remains to optimize the physical properties and microstructure of the anode, both of which were significantly different from that of previous anodes. Injection molding and slip casting yielded anode materials with serious deficiencies, including cracks and holes. Injection molding gave cermet material with the best intrinsic microstructure, i.e., the microstructure of the material between macroscopic flaws was very similar to that of anodes previously made at PNL. Reason for the similarity may have to do with amount of residual binder in the material prior to sintering.

  8. Teknologi Pembuatan Cermet Du0¬2 - Steel Untuk Wadah Limbah Bahan Bakar Bekas Pwr

    OpenAIRE

    Alimah, Siti; Budiarto, Budiarto

    2005-01-01

    DUO­2-STEEL CERMET MANUFACTURING TECHNOLOGY FOR PWR Spent Nuclear Fuel (SNF) CASKS. Assessment of DU02 - Steel cermet manufacturing technology for PWR SNF casks has been done. DU02 - Steel cermet consisting of DU02 particulates and other particulates, embedded in a steel matrix. Cermet SNF casks have the potential for superior performance compared with casks constructed of other materials. The addition of DU02 ceramic particulates can increase SNF cask capacity, improve of repository performa...

  9. Characterization of magnetron sputtered surface coatings by AES

    International Nuclear Information System (INIS)

    Kahler, C.; Endstrasser, N.; Jaksch, S.; Scheier, P.

    2008-01-01

    Full text: Surface coatings produced by magnetron sputtering are investigated by STM and AES. Thin films of silicon nanoparticles are deposited on highly oriented pyrolytic graphite (HOPG) surfaces by magnetron sputtering. These silicon nanoparticle films are manipulated by means of a variable temperature UHV-STM, to realize lithography on the nanometer scale. Several factors affect the stability of the films and thereby the lifetime of the produced surface structures. To investigate the influence of these parameters, various methods like AFM, AES and XPS have to be applied. The dependence of the surface stability on the grade of oxidation is determined from the ratio between silicon and oxygen. This can be achieved by Auger electron spectroscopy. Our Auger spectrometer was modified in order to allow measuring the time development of the Auger spectrum during the oxidation process. Chemical images are generated by collecting an Auger spectrum at every spot as the primary electron beam is rastered across the sample surface. (author)

  10. Enhanced propellant performance via environmentally friendly curable surface coating

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2017-06-01

    Full Text Available Surface coating of granular propellants is widely used in a multiplicity of propellants for small, medium and large caliber ammunition. All small caliber ball propellants exhibit burning progressivity due to application of effective deterrent coatings. Large perforated propellant grains have also begun utilizing plasticizing and impregnated deterrent coatings with the purpose of increasing charge weights for greater energy and velocity for the projectile. The deterrent coating and impregnation process utilizes volatile organic compounds (VOCs and hazardous air pollutants (HAPs which results in propellants that need to be forced air dried which impacts air quality. Propellants undergo temperature fluctuations during their life. Diffusion coefficients vary exponentially with variations in temperature. A small temperature increase can induce a faster migration, even over a short period of time, which can lead to large deviations in the concentration. This large concentration change in the ammunition becomes a safety or performance liability. The presence of both polymeric deterrents and nitroglycerin(NG in the nitrocellulose matrix and organic solvents leads to higher diffusion rates. This results in continued emissions of VOCs and HAPs. Conventional polymers tend to partition within the propellant matrix. In other words, localized mixing can occur between the polymer and underlying propellant. This is due to solvent induced softening of the polymer vehicle over the propellant grain. In effect this creates a path where migration can occur. Since nitrate esters, like NG, are relatively small, it can exude to the surface and create a highly unstable and dangerous situation for the warfighter. Curable polymers do not suffer from this partitioning due to “melting” because no VOC solvents are present. They remain surface coated. The small scale characterization testing, such as closed bomb testing, small scale sensitivity, thermal stability, and

  11. Thermal repellent properties of surface coating using silica

    Science.gov (United States)

    Lee, Y. Y.; Halim, M. S.; Aminudin, E.; Guntor, N. A.

    2017-11-01

    Extensive land development in urban areas is completely altering the surface profile of human living environment. As cities growing rapidly, impervious building and paved surfaces are replacing the natural landscape. In the developing countries with tropical climate, large masses of building elements, such as brick wall and concrete members, absorb and store large amount of heat, which in turn radiate back to the surrounding air during the night time. This bubble of heat is known as urban heat island (UHI). The use of high albedo urban surfaces is an inexpensive measure that can reduce surrounded temperature. Thus, the main focus of this study is to investigate the ability of silica, SiO2, with high albedo value, to be used as a thermal-repelled surface coating for brick wall. Three different silica coatings were used, namely silicone resin, silicone wax and rain repellent and one exterior commercial paint (jota shield paint) that commercially available in the market were applied on small-scale brick wall models. An uncoated sample also had been fabricated as a control sample for comparison. These models were placed at the outdoor space for solar exposure. Outdoor environment measurement was carried out where the ambient temperature, surface temperature, relative humidity and UV reflectance were recorded. The effect of different type of surface coating on temperature variation of the surface brick wall and the thermal performance of coatings as potential of heat reduction for brick wall have been studied. Based on the results, model with silicone resin achieved the lowest surface temperature which indicated that SiO2 can be potentially used to reduce heat absorption on the brick wall and further retains indoor passive thermal comfortability.

  12. Reflectance variability of surface coatings reveals characteristic eigenvalue spectra

    Science.gov (United States)

    Medina, José M.; Díaz, José A.; Barros, Rui

    2012-10-01

    We have examined the trial-to-trial variability of the reflectance spectra of surface coatings containing effect pigments. Principal component analysis of reflectances was done at each detection angle separately. A method for classification of principal components is applied based on the eigenvalue spectra. It was found that the eigenvalue spectra follow characteristic power laws and depend on the detection angle. Three different subsets of principal components were examined to separate the relevant spectral features related to the pigments from other noise sources. Reconstruction of the reflectance spectra by taking only the first subset indicated that reflectance variability was higher at near-specular reflection, suggesting a correlation with the trial-to-trial deposition of effect pigments. Reconstruction by using the second subset indicates that variability was higher at short wavelengths. Finally, reconstruction by using only the third subset indicates that reflectance variability was not totally random as a function of the wavelength. The methods employed can be useful in the evaluation of color variability in industrial paint application processes.

  13. Thermal Cycling of Uranium Dioxide - Tungsten Cermet Fuel Specimens

    Energy Technology Data Exchange (ETDEWEB)

    Gripshover, P.J.; Peterson, J.H.

    1969-12-08

    In phase I tungsten clad cermet fuel specimens were thermal cycled, to study the effects of fuel loading, fuel particle size, stablized fuel, duplex coatings, and fabrication techniques on dimensional stability during thermal cycling. In phase II the best combination of the factors studies in phase I were combined in one specimen for evaluation.

  14. Structure And Properties Of PVD Coatings Deposited On Cermets

    Directory of Open Access Journals (Sweden)

    Żukowska L.

    2015-06-01

    Full Text Available The main aim of the research is the investigation of the structure and properties of single-layer and gradient coatings of the type (Ti,AlN and Ti(C,N deposited by physical vapour deposition technology (PVD on the cermets substrate.

  15. Development of Low Thermal Expansion Tungsten UO 2 Cermet Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Marlowe, M O; Kaznoff, A I

    1970-03-31

    An attempt was made to develop a tungsten-uranium dioxide cermet of high fue 1 loading with thermal expansion approaching that of tungsten and with good dimensional stability on thermal cycling. These goals were sought through the use of tungsten-coated uranium dioxide particles with sufficient locally available void volume to accommodate the difference in thermal expansion between the uranium dioxide and the tungsten matrix and through limitation of plastic deformation in the particles during fabrication to avoid mechanical keying of the particles and the matrix. The particles were vibratorily compacted prior to hot pressing. The thermal expansion of the cermets was determined and they were thermal cycle tested. The thermal expansion of the cermets was considerably closer to that of tungsten than was observed with previously reported specimens of similar composition. However, the thermal cycling of the cermets resulted in intolerable growth. This growth could be accounted for by the agglomeration of gases trapped in the uranium dioxide particles during deposition of the tungsten coating.

  16. Basic research on cermet nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Hiroshi; Sto, Seichi [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Takano, Masahide; Minato, Kazuo; Fukuda, Kosaku

    1998-01-01

    Production of cermet nuclear fuel having fine uranium dioxide (UO{sub 2}) particles dispersed in matrix metal requires basic property data on the compatibility of matrix metal with fission product compounds. It is thermodynamically suggested that, as burnup increases, cesium in oxide fuel reacts with the fuel, other fission products or cladding pipe and produces cesium uranates, cesium molybdate, or cesium chromate in stainless steel cladding pipe. Attempt was made to measure the thermal expansion coefficient and thermal conductivity of cesium uranates (Cs{sub 2}UO{sub 4} and Cs{sub 2}U{sub 2}O{sub 7}), cesium molybdate (Cs{sub 2}MoO{sub 4}) and cesium chromate (Cs{sub 2}CrO{sub 4}). Thermal expansion was measured by X-ray diffraction and determined by Cohen`s method. Thermal conductivity was obtained by measuring thermal diffusion by laser flash method. The thermal expansion of Cs{sub 2}UO{sub 4} and Cs{sub 2}U{sub 2}O{sub 7} is as low as 1.2% for the former and 1.0% for the latter, up to 1000K. The thermal expansion of Cs{sub 2}MoO{sub 4} is as high as that of Cs{sub 2}CrO{sub 4}, 2.1% for the former and 2.5% for the latter at temperatures from room temperature to 873K. Average thermal expansion in this temperature range is 4.4 x 10{sup -5} K{sup -1} for Cs{sub 2}MoO{sub 4} and 4.2 x 10{sup -5} K{sup -1}. The thermal expansion of Cs{sub 2}CrO{sub 4} is four times higher than that of UO{sub 2} and five times higher than that of Cr{sub 2}O{sub 3}. The thermal conductivity of Cs{sub 2}UO{sub 4} is nearly equal to that of Cs{sub 2}U{sub 2}O{sub 7} in absolute value and temperature dependency. Cs{sub 2}U{sub 2}O{sub 7}, having different thermal conductivity between {alpha} and {beta} phases, shows higher conductivity with {beta} than with {alpha}, about 1/4 of that of UO{sub 2} at 1000K. The thermal conductivity of Cs{sub 2}CrO{sub 4} is nearly equal to that of Cs{sub 2}MoO{sub 4} in absolute value and temperature dependency. (N.H.)

  17. 40 CFR 63.5743 - What standards must I meet for aluminum recreational boat surface coating operations?

    Science.gov (United States)

    2010-07-01

    ... recreational boat surface coating operations? 63.5743 Section 63.5743 Protection of Environment ENVIRONMENTAL... Manufacturing Standards for Aluminum Recreational Boat Surface Coating Operations § 63.5743 What standards must I meet for aluminum recreational boat surface coating operations? (a) For aluminum wipedown solvent...

  18. Surface Coating of Wood Building Products National Emission Standards for Hazardous Air Pollutants (NESHAP) Applicability Flowchart

    Science.gov (United States)

    This page contains a January 2005 document that has a flow chart to help you determine if this National Emission Standards for Hazardous Air Pollutants (NESHAP) rule for Surface Coating of Wood Building Products applies to your facility.

  19. Electrochemical corrosion of cermet coatings in artificial marine water

    International Nuclear Information System (INIS)

    Cabot, P.L.; Fernandez, J.; Guilemany, J.M.

    1998-01-01

    The electrochemical corrosion of different WC+12Co coatings sprayed on 34CrMo4 (UNS-G41350) steel by the high velocity oxygen fuel technique has been studied by corrosion potential and impedance measurements considering previous SEM observations and EDX microanalysis. The experiments were conducted in artificial marine water at 20 C and the impedance spectra were obtained at the corresponding corrosion potentials for the substrate, coating and substrate-coating systems. The impedance diagrams indicated that the electrochemical corrosion of the steel-coating systems is controlled by oxygen diffusion through a porous film of corrosion products, as in the case of the shot-blasted steel. In contrast, the corrosion of the coating appeared to be controlled by diffusion of oxygen through the electrolyte. The impedance diagrams obtained for the steel-coating systems depended on the porosities of the cermet coatings, thus being an useful procedure to characterize metals coated by cermets. (orig.)

  20. Remote micro-encapsulation of curium-gold cermets

    International Nuclear Information System (INIS)

    Coops, M.S.; Voegele, A.L.; Hayes, W.N.; Sisson, D.H.

    1980-01-01

    A technique is described for fabricating minature, high-density capsules of curium-244 oxide contained in three concentric jackets of metallic gold (or silver), with the outer surface being free of alpha contamination. The completed capsules are right circular cylinders 0.2500-inch diameter and 0.125-inch tall, with each level of containment soldered (or brazed) closed. A typical capsule would contain approx. 70 mg of 244 Cm (5.7 Ci) mixed with 120 mg of gold powder in the form of a cermet wafer clad in three concentric, 0.010-inch thick, liquid tight jackets. This method of fabrication eliminates voids between the jackets and produces a minimum size, maximum density capsule. Cermet densities of 11.5 g/cc were obtained, with an overall density of 17.3 g/cc for the finished capsule

  1. Dynamic SEM wear studies of tungsten carbide cermets

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined. Etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the WC and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation. The wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  2. A Science-Based Understanding of Cermet Processing

    Energy Technology Data Exchange (ETDEWEB)

    Cesarano, III, Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roach, Robert Allen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kilgo, Alice C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Susan, Donald Francis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Van Ornum, David J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stuecker, John N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shollenberger, Kimberly A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2006-04-01

    This report is a summary of the work completed in FY01 for science-based characterization of the processes used to fabricate 1) cermet vias in source feedthrus using slurry and paste-filling techniques and 2) cermet powder for dry pressing. Common defects found in cermet vias were characterized based on the ability of subsequent processing techniques (isopressing and firing) to remove the defects. Non-aqueous spray drying and mist granulation techniques were explored as alternative methods of creating CND50, the powder commonly used for dry pressed parts. Compaction and flow characteristics of these techniques were analyzed and compared to standard dry-ball-milled CND50. Due to processing changes, changes in microstructure can occur. A microstructure characterization technique was developed to numerically describe cermet microstructure. Machining and electrical properties of dry pressed parts were also analyzed and related to microstructure using this analytical technique.3 Executive SummaryThis report outlines accomplishments in the science-based understanding of cermet processing up to fiscal year 2002 for Sandia National Laboratories. The three main areas of work are centered on 1) increasing production yields of slurry-filled cermets, 2) evaluating the viability of high-solids-loading pastes for the same cermet components, and 3) optimizing cermet powder used in pressing processes (CND50). An additional development that was created as a result of the effort to fully understand the impacts of alternative processing techniques is the use of analytical methods to relate microstructure to physical properties. Recommendations are suggested at the end of this report. Summaries of these four efforts are as follows:1.Increase Production Yields of Slurry-Filled Cermet Vias Finalized slurry filling criteria were determined based on three designs of experiments where the following factors were analyzed: vacuum time, solids loading, pressure drop across the filter paper

  3. Effect of Mo2C content on the properties of TiC/TiB2 base cermets

    International Nuclear Information System (INIS)

    Takagi, Ken-ichi; Osada, Ken; Koike, Wataru; Fujima, Takuya

    2009-01-01

    The effects of Mo 2 C content on the microstructure and mechanical properties of TiC/TiB 2 base cermets were studied using the model cermets with the compositions of TiC/TiB 2 -(11-17)Mo 2 C-24Ni (mass%). TiC and TiB 2 ratio is set to molar ratio of 59:41 that is near quasi-eutectic composition. As a result, both transverse rupture strength and hardness of the cermets showed maxima for the cermet containing 13% Mo 2 C. The cermet achieved remarkable microstructural refinement and still maintained characteristic core-rim structure of the TiC base cermets. TiC/TiB 2 cermets, in addition to TiCN base cermets, are a good alternative material to cemented carbides.

  4. Cermet Ni-ZrO2 by mechanical alloying

    International Nuclear Information System (INIS)

    Leite, Douglas Will

    2010-01-01

    The ZrO 2 and metallic Ni Cermet obtained by Mechanical Alloying - MA is studied in the present work with the objective to prepare solid oxide fuel cells anodes (SOFC). Metallic Ni is added under three different concentrations: 30, 40 and 50% volume. The millings were conducted in SPEX vibratory mill where the influence of milling time, process control additives efficiency, type and geometry of milling vessels were studied. The study of the influence of these variables was made under particle size analysis, surface area determination and resulting material morphology. The use of teflon vessel causes contamination by carbon. On the other side, steel vessel increases the contamination by metallic impurities. The several geometries projected and analyzed for the vessels showed that vessels with larger bottom radius (R.15) showed the best results. After conformation and sintering at 1300 degree C in argon atmosphere the samples reached densities between 60 and 80% of the theoretical density. Microstructures observed by scanning electron microscopy reveal good homogeneity in the Cermet phases distribution. The mechanical alloying technique was considered a good option to obtain Ni- ZrO 2 Cermet. (author)

  5. Spray pyrolytically grown NiAlOx cermets for solar thermal selective ...

    Indian Academy of Sciences (India)

    -cermet-layer structure, because of the ease of fabrication, is the most suitable for a cermet solar selective absorber [7]. Figure 11. Multilayer structure composed of (60/40) nickel to aluminium (1st layer) and (60/40 + 10/90) nickel to aluminium ( ...

  6. Micro-scale mechanical characterization of Inconel cermet coatings deposited by laser cladding

    Directory of Open Access Journals (Sweden)

    Chao Chang

    2016-07-01

    Full Text Available In this study, an Inconel 625-Cr3C2 cermet coating was deposited on a steel alloy by laser cladding. The elastic and plastic mechanical properties of the cermet matrix were studied by the depth sensing indentation (DSI in the micro scale. These results were compared with those obtained from an Inconel 600 bulk specimen. The values of Young's modulus and hardness of cermet matrix were higher than those of an Inconel 600 bulk specimen. Meanwhile, the indentation stress–strain curve of the cermet matrix showed a strain hardening value which was more than twice the one obtained for the Inconel 600 bulk. Additionally, the mechanical properties of unmelted Cr3C2 ceramic particles, embedded in the cermet matrix were also evaluated by DSI using a spherical indenter.

  7. Micro-scale mechanical characterization of Inconel cermet coatings deposited by laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ch.; Verdi, D.; Garrido, M.A.; Ruiz-Hervias, J.

    2016-07-01

    In this study, an Inconel 625-Cr3C2 cermet coating was deposited on a steel alloy by laser cladding. The elastic and plastic mechanical properties of the cermet matrix were studied by the depth sensing indentation (DSI) in the micro scale. These results were compared with those obtained from an Inconel 600 bulk specimen. The values of Young's modulus and hardness of cermet matrix were higher than those of an Inconel 600 bulk specimen. Meanwhile, the indentation stress–strain curve of the cermet matrix showed a strain hardening value which was more than twice the one obtained for the Inconel 600 bulk. Additionally, the mechanical properties of unmelted Cr3C2 ceramic particles, embedded in the cermet matrix were also evaluated by DSI using a spherical indenter. (Author)

  8. U-PuO2, U-PuC, U-PuN cermet fuel for fast reactor

    Science.gov (United States)

    Mishra, Sudhir; Kaity, Santu; Banerjee, Joydipta; Nandi, Chiranjeet; Dey, G. K.; Khan, K. B.

    2018-02-01

    Cermet fuel combines beneficial properties of both ceramic and metal and attracts global interest for research as a candidate fuel for nuclear reactors. In the present study, U matrix PuC/PuN/PuO2 cermet for fast reactor have been fabricated on laboratory scale by the powder metallurgy route. Characterization of the fuel has been carried out using Dilatometer, Differential Thermal analysis (DTA), X-ray diffractometer and Optical microscope. X ray diffraction study of the fuel reveals presence of different phases. The PuN dispersed cermet was observed to have high solidus temperature as compared to PuC and PuO2 dispersed cermet. Swelling was observed in U matrix PuO2 cermet which also showed higher thermal expansion. Among the three cermets studied, U matrix PuC cermet showed maximum thermal conductivity.

  9. Flank wear study of coating carbides and cermet inserts during the dry high speed turning of AISI 1045 steel; Estudio del desgaste del flanco de carburos recubiertos y cermet durante el torneado de alta velocidad en seco del acero AISI 1045

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Gonzalez, L. W.; Perez-Rodriguez, R.; Zambrano-Robledo, P.; Guerrero-Mata, M.; Dumitrescu, L.

    2011-07-01

    This work deals with the experimental study of the flank wear evolution of two coating carbide inserts and a cermet insert during the dry finishing turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. The results were analyzed using the variance analysis and lineal regression analysis in order to describe the relationship between the flank wear and machining time, obtaining the adjusted model equation. The investigation demonstrated a significant effect of cutting speed and machining time on the flank wear at high speed machining. The three coating layers insert showed the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speeds. (Author) 19 refs.

  10. Ag-Zr(Sc)O{sub 2} cermet cathode for reduced temperature SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, K.; Hosoda, K.; Dokiya, M. [Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Lan, T.N. [Fuel Cell Group, Energy Electronics Institute, National Institute of Advanced Industrial Science and Technology, 1-1-4, Umezono, Tsukuba, Ibaraki (Japan); Yasumoto, K. [Materials Science Research Laboratory, Central Research Institute of Electric Power Industry, 2-6-1 Kagasaka, Yokosuka 240-0196 (Japan); Wang, S. [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Ding-Xi RD. 200050 Shanghai (China)

    2004-10-29

    Polarization characteristics of Ag-(Sc{sub 0.10}Ce{sub 0.01}) Zr{sub 0.89}O{sub 2}, SSZ, cermet cathodes were investigated in order to develop a new cathode for reduced temperature solid oxide fuel cells, SOFCs. Ag-SSZ cermet cathode was prepared by mixing Ag powder with SSZ powder using a high-energy ball mill in a vacuum and pasting the cermet onto yttria-stabilized zirconia, YSZ, electrolyte. An Ag-SSZ cermet cathode achieved as high as 0.8 S/cm{sup 2} of interfacial conductivity, {sigma}{sub E}, at 773 K in air. Morphology and the {sigma}{sub E} of this Ag/SSZ cermet cathode were unchanged at 773 K in air by application of cathodic DC bias of 0.5 V. These results suggest that this Ag-SSZ cermet cathode has enough electrode reactivity and durability for a 773-K operating SOFCs for 700 h. This high-electrode reactivity can be originated from an increase of reaction site and a small activation energy, E{sub a}. These results suggested that an Ag-SSZ might be a suitable cathode material for SOFCs operated at 773 K. These observations show the Ag/SSZ ratio for cathode of SOFCs operated at 773 K, suggesting that morphology of cermet would have a large effect on cathode property.

  11. Characterization of TiC-FeCrMn Cermets Produced by Powder Metallurgy Method

    Directory of Open Access Journals (Sweden)

    Märt Kolnes

    2015-09-01

    Full Text Available TiC-NiMo cermets combine relatively low density with high hardness. Because nickel is known as a toxin and allergen and allergy to nickel is a phenomenon which has assumed growing importance in recent years there has been a flurry of activity to find alternatives to the nickel binder in cermets. It is also the global research and technical development trend in the powder metallurgy cermets industry. In present research TiC-based cermets with FeCrMn binder system were fabricated. Three different sintering conditions were used (vacuum sintering, sinter/HIP and sintering under low Ar pressure. Because of high vapor pressure of manganese different sintering conditions and technologies were investigated to depress the Mn-loss during sintering. Chemical composition of TiC-FeCrMn cermets after different sintering conditions were analyzed by energy-dispersive X-ray spectroscopy (EDS and mechanical properties – hardness and fracture toughness were evaluated on the samples. Results of research showed that Ni-free TiC-based CrMn-steels bonded cermets compare unfavorably with cermets bonded with CrNi austenitic steels in terms of fracture toughness and corrosion resistance. Noticeable Mn-loss during vacuum sintering can be avoided when sintering under low Ar gas pressure.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7364

  12. Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

    Science.gov (United States)

    CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

  13. Cytotoxicity of organic surface coating agents used for nanoparticles synthesis and stability.

    Science.gov (United States)

    Zhang, Ying; Newton, Brandon; Lewis, Eybriunna; Fu, Peter P; Kafoury, Ramzi; Ray, Paresh C; Yu, Hongtao

    2015-06-01

    Impact on health by nanomaterials has become a public concern with the great advances of nanomaterials for various applications. Surface coating agents are an integral part of nanoparticles, but not enough attention has been paid during toxicity tests of nanoparticles. As a result, there are inconsistent toxicity results for certain nanomaterials. In this study, we explored the cytotoxicity of eleven commonly used surface coating agents in two cell lines, human epidermal keratinocyte (HaCaT) and lung fibroblast (CRL-1490) cells, at surface coating agent concentrations of 3, 10, 30, and 100 μM. Two exposure time points, 2 h and 24 h, were employed for the study. Six of the eleven surface coating agents are cytotoxic, especially those surfactants with long aliphatic chains, both cationic (cetyltrimethylammonium bromide, oleylamine, tetraoctylammonium bromide, and hexadecylamine) and anionic (sodium dodecylsulfate). In addition, exposure time and the use of different cell lines also affect the cytotoxicity results. Therefore, factors such as cell lines used and exposure times must be considered when conducting toxicity tests or comparing cytotoxicity results. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. 40 CFR 63.5755 - How do I demonstrate compliance with the aluminum recreational boat surface coating spray gun...

    Science.gov (United States)

    2010-07-01

    ... the aluminum recreational boat surface coating spray gun cleaning work practice standards? 63.5755... surface coating spray gun cleaning work practice standards? You must demonstrate compliance with the aluminum coating spray gun cleaning work practice standards by meeting the requirements of paragraph (a) or...

  15. 16 CFR 1145.2 - Paint (and other similar surface-coating materials) containing lead; toys, children's articles...

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Paint (and other similar surface-coating materials) containing lead; toys, children's articles, and articles of furniture bearing such paint (or... TO OTHER ACTS UNDER THE CONSUMER PRODUCT SAFETY ACT § 1145.2 Paint (and other similar surface-coating...

  16. Cermet based metamaterials for multi band absorbers over NIR to LWIR frequencies

    International Nuclear Information System (INIS)

    Pradhan, Jitendra K; Behera, Gangadhar; Anantha Ramakrishna, S; Agarwal, Amit K; Ghosh, Amitava

    2017-01-01

    Cermets or ceramic-metals are known for their use in solar thermal technologies for their absorption across the solar band. Use of cermet layers in a metamaterial perfect absorber allows for flexible control of infra-red absorption over the short wave infra-red, to long wave infra-red bands, while keeping the visible/near infra-red absorption properties constant. We design multilayered metamaterials consisting of a conducting ground plane, a low metal volume fraction cermet/ZnS as dielectric spacer layers, and a top structured layer of an array of circular discs of metal/high volume metal fraction cermet that give rise to specified absorption bands in the near-infra-red (NIR) frequencies, as well as any specified band at SWIR–LWIR frequencies. Thus, a complete decoupling of the absorption at optical/NIR frequencies and the infra-red absorption behaviour of a structured metamaterial is demonstrated. (paper)

  17. Microstructural characterization of cermet-steel interface in rock drilling tool

    International Nuclear Information System (INIS)

    Ybarra, L.A.C.; Molisani, A.L.; Yoshimura, H.N.

    2010-01-01

    Rock drilling tools basically present a WC cermet bonded to a steel shank. The interface cermet-steel plays fundamental role during drilling operation, since the fracture of this interface is the main failure mode of the tools. In this work, the microstructure of this interface in crown samples (type A), prepared in an industrial like process, was evaluated. In this process, a WC-containing powder was infiltrated with a copper alloy at 1100 deg C in a graphite mold previously mounted with a 1020 steel tube. The powder was characterized by XRD analysis and the cross-section microstructure of cermet-steel was analyzed using SEM-EDS. It was observed that Ni and small amount of Cu from cermet matrix diffused into the superficial region of the steel, and the Cu alloy dissolved and penetrated along the steel grain boundaries, resulting in good metallurgical bonding of the interface.(author)

  18. The Influence of Sintering Temperature of Reactive Sintered (Ti, MoC-Ni Cermets

    Directory of Open Access Journals (Sweden)

    Marek Jõeleht

    2015-09-01

    Full Text Available Titanium-molybdenum carbide nickel cermets ((Ti, MoC-Ni were produced using high energy milling and reactive sintering process. Compared to conventional TiC-NiMo cermet sintering the parameters for reactive sintered cermets vary since additional processes are present such as carbide synthesis. Therefore, it is essential to acquire information about the suitable sintering regime for reactive sintered cermets. One of the key parameters is the final sintering temperature when the liquid binder Ni forms the final matrix and vacancies inside the material are removed. The influence of the final sintering temperature is analyzed by scanning electron microscopy. Mechanical properties of the material are characterized by transverse rupture strength, hardness and fracture toughness.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7179

  19. Electric arc, water jet cutting of metals

    International Nuclear Information System (INIS)

    Bruening, D.

    1991-01-01

    For thermal dismantling and cutting of metallic components, as electric arc, water jet cutting method was developed that can be used for underwater cutting work up to a depth of 20 m. Short-circuiting of a continuously fed electrode wire in contact with the metal generates an electric arc which induces partial melting of the metal, and the water jet surrounding the wire rinses away the molten material, thus making a continuous kerf in the material. The method was also tested and modified to allow larger area, surface cutting and removal of metallic surface coatings. This is achieved by melting parts of the surface with the electric arc and subsequent rinsing by the water jet. The cutting and melting depth for surface removal can be accurately controlled by the operating parameters chosen. (orig./DG) [de

  20. TiO2 Surface Coating of Mn-Zn Dopped Ferrites Study

    DEFF Research Database (Denmark)

    Solný, Tomáš; Ptacek, Petr; Másilko, Jiří

    2016-01-01

    This study deals with TiO2 coating of powder Mn-Zn ferrite in order to recieve photocatalytic layer on the top of these particles, forming core-shell catalyst. Powder catalysts are of great advance over the world due to the high surface area, considering the kinetics proceeds through heterogenous...... phase boundary catalysis. However their withdrawal from cleaning systems often requires energetically and economically demanding processes such as filtration and ultrafiltration. Since the ferrite is magnetic, the advantage of such formed core-shell photocatalyst is easibility of removing from...... photocatalytic decomposition system using external magnetic field. In this study the surface coating is performed, using Ti alkoxides mixtures with nanosized TiO2 particles and C and Au coating to form film layer of TiO2 on the surface of ferrite. XRD, SEM – EDS analyses are employed to study surface coating....

  1. Supramolecular polymers as surface coatings: rapid fabrication of healable superhydrophobic and slippery surfaces.

    Science.gov (United States)

    Wei, Qiang; Schlaich, Christoph; Prévost, Sylvain; Schulz, Andrea; Böttcher, Christoph; Gradzielski, Michael; Qi, Zhenhui; Haag, Rainer; Schalley, Christoph A

    2014-11-19

    Supramolecular polymerization for non-wetting surface coatings is described. The self-assembly of low-molecular-weight gelators (LMWGs) with perfluorinated side chains can be utilized to rapidly construct superhydrophobic, as well as liquid-infused slippery surfaces within minutes. The lubricated slippery surface exhibits impressive repellency to biological li-quids, such as human serum and blood, and very fast self-healing. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Surface coatings of unsaturated polyester resin Kamper wood (Dry obalan ops spp.) by using UV radiation

    International Nuclear Information System (INIS)

    Sugiarto Danu; Yusuf Sudo Hadi; Novi Eka Putri

    1999-01-01

    Kamper wood (Dryobalanops spp.) has high contribution in wood working industry and most of them need surface coating process. Radiation curing of surface coating, especially the use of ultra-violet (UV) light have potential to give contribution in the wood finishing. The experiment on surface coating of kamper wood has been conducted by using UV-radiation. Unsaturated polyester resin with the commercial name of Yucalac type 157 was used as coating materials after being added with styrene monomer, some fillers and radical photoinitiator of 2-hydroxy-2-2-methyl-l- phenyl propanone. Four photoinitiator concentration levels of 1.5 ; 2 ; 2.5 and 3 % by weight of resin were used. The coating materials were coated onto the wood panel samples by using high pressure sprayer. The wood samples were then exposed to irradiation by using 80 Watts/cm UV-source with variable conveyor speed of 3 ; 4 ; 5 and 5.8 m/min. Formulation of coating materials, pendulum hardness, adhesion, and gloss of cured films were evaluated

  3. Behavior of Ag nanoparticles in soil: Effects of particle surface coating, aging and sewage sludge amendment

    International Nuclear Information System (INIS)

    Whitley, Annie R.; Levard, Clément; Oostveen, Emily; Bertsch, Paul M.; Matocha, Chris J.; Kammer, Frank von der; Unrine, Jason M.

    2013-01-01

    This study addressed the relative importance of particle coating, sewage sludge amendment, and aging on aggregation and dissolution of manufactured Ag nanoparticles (Ag MNPs) in soil pore water. Ag MNPs with citrate (CIT) or polyvinylpyrrolidone (PVP) coatings were incubated with soil or municipal sewage sludge which was then amended to soil (1% or 3% sludge (w/w)). Pore waters were extracted after 1 week and 2 and 6 months and analyzed for chemical speciation, aggregation state and dissolution. Ag MNP coating had profound effects on aggregation state and partitioning to pore water in the absence of sewage sludge, but pre-incubation with sewage sludge negated these effects. This suggests that Ag MNP coating does not need to be taken into account to understand fate of AgMNPs applied to soil through biosolids amendment. Aging of soil also had profound effects that depended on Ag MNP coating and sludge amendment. -- Highlights: •Silver nanoparticle coating affects fate in unamended soils. •Citrated coated silver nanoparticles could be found in pore water for up to six months. •Pre-incubation of silver nanoparticles in sewage sludge negated effects of surface coating. •Weathered or reprecipitated particles found in pore water for up to two months in sludge amended soils. •Particle surface coating, sewage sludge amendment and aging all have important impacts. -- Behavior of manufactured silver nanoparticles in soil depends on surface coating, contact with sewage sludge, and aging

  4. Conformal surface coatings to enable high volume expansion Li-ion anode materials.

    Science.gov (United States)

    Riley, Leah A; Cavanagh, Andrew S; George, Steven M; Jung, Yoon Seok; Yan, Yanfa; Lee, Se-Hee; Dillon, Anne C

    2010-07-12

    An alumina surface coating is demonstrated to improve electrochemical performance of MoO(3) nanoparticles as high capacity/high-volume expansion anodes for Li-ion batteries. Thin, conformal surface coatings were grown using atomic layer deposition (ALD) that relies on self-limiting surface reactions. ALD coatings were tested on both individual nanoparticles and prefabricated electrodes containing conductive additive and binder. The coated and non-coated materials were characterized using transmission electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy, and galvanostatic charge/discharge cycling. Importantly, increased stability and capacity retention was only observed when the fully fabricated electrode was coated. The alumina layer both improves the adhesion of the entire electrode, during volume expansion/contraction and protects the nanoparticle surfaces. Coating the entire electrode also allows for an important carbothermal reduction process that occurs during electrode pre-heat treatment. ALD is thus demonstrated as a novel and necessary method that may be employed to coat the tortuous network of a battery electrode.

  5. Estudio del desgaste del flanco de carburos recubiertos y cermet durante el torneado de alta velocidad en seco del acero AISI 1045

    Directory of Open Access Journals (Sweden)

    Hernández-González, L. W.

    2011-06-01

    Full Text Available This work deals with the experimental study of the flank wear evolution of two coating carbide inserts and a cermet insert during the dry finishing turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. The results were analyzed using the variance analysis and lineal regression analysis in order to describe the relationship between the flank wear and machining time, obtaining the adjusted model equation. The investigation demonstrated a significant effect of cutting speed and machining time on the flank wear at high speed machining. The three coating layers insert showed the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speeds.

    El objetivo de este trabajo es el estudio experimental de la evolución del desgaste del flanco respecto al tiempo de dos insertos de carburo recubiertos y un cermet durante el torneado de acabado en seco del acero AISI 1045 con velocidades de corte de 400, 500 y 600 m/min. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión lineal para describir la relación entre el desgaste del flanco y el tiempo de maquinado, obteniéndose la ecuación del modelo ajustado. La investigación demostró un efecto significativo de la velocidad de corte y del tiempo de maquinado en el desgaste del flanco en el maquinado de alta velocidad. El mejor desempeño se obtuvo para el carburo recubierto con tres capas, mientras que el carburo con dos capas sufrió el mayor desgaste a elevadas velocidades de corte.

  6. Final Rule to Reduce Toxic Air Pollutants from Surface Coating of Plastic Parts and Products Fact Sheet

    Science.gov (United States)

    This page contains an August 2004 fact sheet with information regarding the final NESHAP for Surface Coating of Plastic Parts and Products. This document provides a summary of the information for the information for this regulation.

  7. THE SIZE AND SURFACE COATING OF NANOSILVER DIFFERENTIALLY AFFECTS BIOLOGICAL ACTIVITY IN BLOOD BRAIN BARRIER (RBEC4) CELLS.

    Science.gov (United States)

    Linking the physical properties of nanoparticles with differences in their biological activity is critical for understanding their potential toxicity and mode of action. The influence of aggregate size, surface coating, and surface charge on nanosilver's (nanoAg) movement through...

  8. Impact of nanosilver on various DNA lesions and HPRT gene mutations - effects of charge and surface coating

    Czech Academy of Sciences Publication Activity Database

    Huk, A.; Izak-Nau, E.; el Yamani, N.; Uggerud, H.; Vadset, M.; Zasońska, Beata Anna; Duschl, A.; Dusinska, M.

    2015-01-01

    Roč. 12, 24 July (2015), 25_1-25_20 ISSN 1743-8977 Institutional support: RVO:61389013 Keywords : silver nanomaterials * surface charge * surface coating Subject RIV: CD - Macromolecular Chemistry Impact factor: 8.649, year: 2015

  9. High temperature deformation mechanisms of cemented carbides and cermets

    OpenAIRE

    Buss, Katharina

    2004-01-01

    The motivation of this work derives from the need of the cutting tool industry to improve its products in order to support harder and harder working conditions, namely increasing cutting speeds and working on stronger modern materials. The lifetime of the tools is limited by plastic deformation that occurs at the cutting edge under working conditions, which involve high temperatures and stresses. The high temperature deformation of the materials that are used for the production of cutting too...

  10. Study of performance of high speed turning using the volumetric dimension coefficient of resultant cutting force; Estudio del rendimiento del torneado de alta velocidad utilizando el coeficiente de dimension volumetrica de la fuerza de corte resultante

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Gonzalez, L. W.; Perez-Rodriguez, R.; Zambrano-Robledo, P. C.; Siller-Carrillo, H. R.; Toscano-Reyes, H.

    2013-07-01

    This work deals with the experimental study of the resultant cutting force evolution of two coating carbide and a cermet inserts, during the dry turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. A new criterion for machinability study, the coefficient of volumetric dimension of cutting force, it is introduced. The investigation showed a better performance of cermet for moderate and intermediate cutting speeds, while at high cutting speed and final machining time, the three layers coated carbide achieved the best result. The factorial analysis of variance demonstrated a significant effect of machining time on the coefficient of volumetric dimension of resultant cutting force, while the material insert factor and their interaction, for intermediate cutting speed was just significant. (Author)

  11. Thermal properties and thermal shock resistance of liquid phase sintered ZrC-Mo cermets

    International Nuclear Information System (INIS)

    Landwehr, Sean E.; Hilmas, Gregory E.; Fahrenholtz, William G.; Talmy, Inna G.; Wang Hsin

    2009-01-01

    The linear thermal expansion coefficient (CTE), heat capacity, and thermal conductivity, were investigated as a function of temperature for hot pressed ZrC and liquid phase sintered ZrC-Mo cermets. The ZrC and the ZrC-Mo cermets had the same CTE at 50 deg. C (∼5.1-5.5 ppm deg. C -1 ), but the CTE of ZrC increased to ∼12.2 ppm deg. C -1 at 1000 deg. C compared to ∼7.2-8.5 ppm deg. C -1 for the ZrC-Mo cermets. Heat capacity was calculated using a rule of mixtures and previously reported thermodynamic data. Thermal diffusivity was measured with a laser flash method and was, in turn, used to calculate thermal conductivity. Thermal conductivity increased linearly with increasing temperature for all compositions and was affected by solid solution formation and carbon deficiency of the carbide phases. Hot pressed ZrC had the highest thermal conductivity (∼30-37 W m -1 K -1 ). The nominally 20 and 30 vol% Mo compositions of the ZrC-Mo cermets had a lower thermal conductivity, but the thermal conductivity generally increased with increasing Mo content. Water quench thermal shock testing showed that ZrC-30 vol% Mo had a critical temperature difference of 350 deg. C, which was ∼120 deg. C higher than ZrC. This increase was due to the increased toughness of the cermet compared to ZrC.

  12. Microstructural evolution in WC-Co cermet reinforced - A17075 metal matrix composites by stir casting

    Science.gov (United States)

    Gopal Krishna, U. B.; Ranganatha, P.; Auradi, V.; Mahendra Kumar, S.; Vasudeva, B.

    2016-09-01

    Aluminium metal matrix composites (AMMCs) are preferred because of their enhanced properties like high strength to weight ratio, stiffness and wear resistance. In the present work, an attempt is made to develop cermet (WC-Co) reinforced with Al7075 metal matrix composite by stir casting technique. WC-Co cermet is reduced to an average size of 10μm through ball milling using Alumina as grinding media. Ball milled WC-Co Cermet in an amount of 6 wt. % is used as reinforcement in Al7075 matrix. Microstructural characterization of the prepared composites is carried out using SEM/EDX and XRD studies. X-ray diffraction studies have revealed the peaks corresponding to α-Al, WC, Co and minor Al5W phases. SEM/EDX characterization revealed the uniform distribution of cermet in Al matrix. Further studies also revealed that, addition of WC-Co cermet to Al7075 matrix has resulted in improvement in hardness and Densities of Al7075 matrix.

  13. Effect of graphite content on magnetic and mechanical properties of TiC-TiN-Mo-Ni cermets

    Science.gov (United States)

    Zhang, Man; Yang, Qingqing; Xiong, Weihao; Huang, Bin; Ruan, Linji; Mao, Qiao; Li, Shengtao

    2018-04-01

    TiC-10TiN-6Mo-xGr-yNi (mol%, Gr represents graphite, x = 0, 2, 4, 6, 8, and y = 15, 30) cermets were prepared by powder metallurgy method, in order to inverstigate the effect of Gr content on magnetic and mechanical properties of TiC-TiN-Mo-Ni cermets. Room-temperature (RT) saturation magnetization (Ms) and remanence (Mr) of cermets increased with increasing x. This was mainly attributed to that the total content of non-ferromagnetic carbonitride-forming elements Ti and Mo in Ni-based binder phase decreased with increasing x. At the same x, cermets for y = 15 had lower RT Ms and Mr than those for y = 30. Cermets containing more than 2 mol% Gr became ferromagnetic at RT. Bending strength of cermets first increased and then decreased with increasing x. It reached the maximum at x = 2, mainly due to high total content of solutes Ti and Mo in Ni-based binder phase, and moderate thickness of outer rim of Ti(C,N) ceramic grains. Hardness of cermets was not significantly affected by x, mainly due to the combined action of the decrease of the total content of Ti and Mo in binder phase and the increase of the volume fraction of ceramic grains. At the same x, cermets for y = 15 had lower bending strength and higher hardness than those for y = 30.

  14. Surface coating influence on elastic properties of spruce wood by means of holographic vibration mode visualization

    Science.gov (United States)

    Bongova, M.; Urgela, Stanislav

    1999-07-01

    Physicoacoustical properties of wood influenced by surface coating are studied by modal analysis. Resonant spruce plates were coated by stain, nitrocellulose varnish, special violin paint and shellac. The modal testing was performed by electronic speckle pattern interferometry. For this purpose, equipment called VIBROVIZER was used. The collected values of physicoacoustical characteristics (density, Young's modulus, acoustic constant) were compared using the graphic plots of data. The 3D plots help to evaluate wooden plates from a viewpoint of the quality control. This fact offers new opportunity for musical instrument manufacturers.

  15. Creep of MDF panels under constant load and cyclic environmental conditions. Influence of surface coating

    OpenAIRE

    Fernández-Golfín Seco, J. I.; Díez Barra, M. Rafael

    1997-01-01

    Four different strategies of surface coating (based on 80 g m2 melamin impregnated papers) were used on 19 mm thick commercial MDF panels to assess its reological behaviour under cyclic humidity conditions (20ºC 30 % rh-20ºC 90 % rh). Three different levels of stress (20 %, 30 % and 40 %), based on the ultimate load in bending, were used. Tests were conducted by means of the three points load system. For the same stress level, the relative creep of MDF panels was higher than that in par...

  16. Cytotoxicity Induced by Engineered Silver Nanocrystallites Is Dependent on Surface Coatings and Cell Types

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, Anil K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Pelletier, Dale A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Wang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Morrell-Falvey, Jennifer L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Gu, Baohua [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division; Doktycz, Mitchel J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)

    2012-01-04

    Due to their unique antimicrobial properties silver nanocrystallites have garnered substantial recognition and are used extensively in biomedical applications such as wound dressing, surgical instruments and as bone substitute material. They are also released into unintended locations such as the environment or biosphere. Therefore it is imperative to understand the potential interactions, fate and transport of nanoparticles with environmental biotic systems. Although numerous factors including the composition, size, shape, surface charge and capping molecule of nanoparticles are known to influence the cell cytotoxicity, our results demonstrate for the first time that surface coatings are a major determinant in eliciting the potential cytotoxicity and cell interactions of silver nanoparticles. In the present investigation, silver nanocrystallites with nearly uniform size and shape distribution but with different surface coatings, imparting overall high negativity to high positivity, were synthesized. These nanoparticles were poly (diallyldimethylammonium) chloride-Ag, biogenic-Ag, colloidal-Ag (uncoated) and oleate-Ag with zeta potentials +45±5 mV, -12± 2 mV, -42±5 mV and -45±5 mV respectively; the particles were thoroughly purified so as to avoid false cytotoxicity interpretations. A systematic investigation on the cytotoxic effects, cellular response and membrane damage caused by these four different silver nanoparticles were evaluated using multiple toxicity measurements on mouse macrophage (RAW-264.7) and lung epithelial (C-10) cell lines. From a toxicity perspective, our results clearly indicated that the cytotoxicity was depend on various factors such as synthesis procedure, surface coat or surface charge and the cell-type for the different silver nanoparticles that were investigated. Finally, poly (diallyldimethylammonium) chloride -Ag was found to be the most toxic, followed by biogenic-Ag and oleate-Ag, whereas uncoated-Ag was found to be least toxic

  17. Low Cost Nuclear Thermal Rocket Cermet Fuel Element Environment Testing

    Science.gov (United States)

    Bradley, David E.; Mireles, Omar R.; Hickman, Robert R.

    2011-01-01

    Deep space missions with large payloads require high specific impulse (Isp) and relatively high thrust in order to achieve mission goals in reasonable time frames. Conventional, storable propellants produce average Isp. Nuclear thermal rockets (NTR) capable of high Isp thrust have been proposed. NTR employs heat produced by fission reaction to heat and therefore accelerate hydrogen which is then forced through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high temperature hydrogen exposure on fuel elements is limited. The primary concern is the mechanical failure of fuel elements which employ high-melting-point metals, ceramics or a combination (cermet) as a structural matrix into which the nuclear fuel is distributed. It is not necessary to include fissile material in test samples intended to explore high temperature hydrogen exposure of the structural support matrices. A small-scale test bed designed to heat fuel element samples via non-contact RF heating and expose samples to hydrogen is being developed to assist in optimal material and manufacturing process selection without employing fissile material. This paper details the test bed design and results of testing conducted to date.

  18. Fabrication of cermet bearings for the control system of a high temperature lithium cooled nuclear reactor

    Science.gov (United States)

    Yacobucci, H. G.; Heestand, R. L.; Kizer, D. E.

    1973-01-01

    The techniques used to fabricate cermet bearings for the fueled control drums of a liquid metal cooled reference-design reactor concept are presented. The bearings were designed for operation in lithium for as long as 5 years at temperatures to 1205 C. Two sets of bearings were fabricated from a hafnium carbide - 8-wt. % molybdenum - 2-wt. % niobium carbide cermet, and two sets were fabricated from a hafnium nitride - 10-wt. % tungsten cermet. Procedures were developed for synthesizing the material in high purity inert-atmosphere glove boxes to minimize oxygen content in order to enhance corrosion resistance. Techniques were developed for pressing cylindrical billets to conserve materials and to reduce machining requirements. Finishing was accomplished by a combination of diamond grinding, electrodischarge machining, and diamond lapping. Samples were characterized in respect to composition, impurity level, lattice parameter, microstructure and density.

  19. Structure and strength of carbide-steel cermet and their changes during heat treatment

    International Nuclear Information System (INIS)

    Dariel, M.P.; Frage, N.R.; Kaputkina, L.M.; Kaputkin, D.M.; Sverdlova, N.R.

    2004-01-01

    Both homogeneous and 'graded' materials were produced by pressing and sintering of titanium carbide TiC x (0.7 x takes place during the joining. If the titanium carbide is carbon deficient that the carbon goes from the steel binder to TiC x , and this redistribution intensity with the x decreases. So-named graded cermets were produced on controlled distribution of TiC x with different x. An additional flow of carbon from C-rich to C-poor TiC x layers was obtained in these cermets. These changes both in the steel and TiC x compositions result in changes in such processes as austenitization, carbide dissolution and precipitation, and martensitic transformation. Both general strength of the material and the gradient of properties in graded cermets can be increased using kinetic factors of element redistribution and structure changes resulted from the heat treatment. (author)

  20. Characterization of porous texture of cermet electrode for steam electrolysis at intermediate temperature

    International Nuclear Information System (INIS)

    Deslouis, C.; Keddam, M.; Rahmouni, K.; Takenouti, H.; Grasset, F.; Lacroix, O.; Sala, B.

    2011-01-01

    Electrodes designed for PCEC (Proton Conducting Electrolyzing Cell) should ensure both electron and proton conductions and also allowed the supply or the draining of gaseous phase such as steam, hydrogen and oxygen. Porous cermet electrodes fulfil these requirements: percolated metallic phase for electron conduction, ceramic for proton conduction, and pores for transport of reactant and products in gas phase. The electrochemical reactions will take place at boundaries of these three phases, commonly named triple points. Therefore, the cermet electrode has to possess a sufficient open porosity and the expanded metallic surface area exposed to pores as large as possible. In this work, the pore texture of cermet electrodes was characterized by means of Electrochemical Impedance Spectroscopy in aprotic liquid medium. The parameter regression calculation based on de Levie's transmission-line model allowed us to determine the pore texture characterized by expanded surface area, number, mean radius of pores, and open porosity.

  1. Analyzing surface coatings in situ: High-temperature surface film analyzer developed

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Scientists at Argonne National Laboratory (ANL) have devised a new instrument that can analyze surface coatings under operating conditions. The High-Temperature Surface Film Analyzer is the first such instrument to analyze the molecular composition and structure of surface coatings on metals and solids under conditions of high temperature and pressure in liquid environments. Corrosion layers, oxide coatings, polymers or paint films, or adsorbed molecules are examples of conditions that can be analyzed using this instrument. Film thicknesses may vary from a few molecular layers to several microns or thicker. The instrument was originally developed to study metal corrosion in aqueous solutions similar to the cooling water systems of light-water nuclear reactors. The instrument may have use for the nuclear power industry where coolant pipes degrade due to stress corrosion cracking, which often leads to plant shutdown. Key determinants in the occurrence of stress corrosion cracking are the properties and composition of corrosion scales that form inside pipes. The High-Temperature Surface Analyzer can analyze these coatings under laboratory conditions that simulate the same hostile environment of high temperature, pressure, and solution that exist during plant operations. The ability to analyze these scales in hostile liquid environments is unique to the instrument. Other applications include analyzing paint composition, corrosion of materials in geothermal power systems, integrity of canisters for radioactive waste storage, corrosion inhibitor films on piping and drilling systems, and surface scales on condenser tubes in industrial hot water heat exchangers. The device is not patented

  2. Impact of surface coated magnetite used in magnetic drug delivery system on immune response

    Science.gov (United States)

    Oaku, Yoshihiro; Tamada, Junya; Mishima, Fumihito; Akiyama, Yoko; Osako, Mariana Kiomy; Koriyama, Hiroshi; Nakagami, Hironori; Nishijima, Shigehiro

    2015-05-01

    Magnetic drug delivery system (MDDS) is a technique to effectively accumulate drugs, which are combined with ferromagnetic particles, into the affected area using magnetic force control. This study intends to apply MDDS for immunotherapy by enhancing immune responses by a surface treatment of a ferromagnetic particle. The objective of this study is to give the adjuvant effect to a ferromagnetic particle by the surface treatment with alum, which is known as one of the common adjuvants that activates inflammasome pathway. First, magnetite was prepared as a ferromagnetic particle and coated with alum. Alum-coated magnetite increased the expression of caspase-1, which is an activated indicator of inflammasome, in the culture of human monocyte cell (THP-1 cell). To evaluate the potential of the surface coated particles, the particles were subcutaneously injected to mice with a peptide vaccine. As a result, the antibody titer was increased by the surface coated particles as assessed by ELISA. Although a magnetic force has not yet applied in this study, the administration experiment to mice using magnetic force control is our next step. In conclusion, we modified the immune response to magnetite by coating the surface with alum. This can lead to a clinical application for vaccine therapy in future.

  3. Determination of elastic mechanical characteristics of surface coatings from analysis of signals obtained by impulse excitation

    Science.gov (United States)

    Nyaguly, E.; Craştiu, I.; Deac, S.; Gozman-Pop, C.; Drăgănescu, G.; Bereteu, L.

    2018-01-01

    Most of the surface coatings are based on the synthetic polymers, which are substances composed from very large molecules that form tough, flexible, adhesive films when applied to surfaces. The other components of surface coverings materials are pigments that provide colour, opacity, gloss and other properties. Surface coatings are two-phase composite materials: constitute a polymer matrix on the one side, and on the other side of the pigments and additives dispersed in the matrix. Their role is not only aesthetically but also to ensure anticorrosive protection or even improve some mechanical properties of coated surfaces. In this paper it will follow, starting from the mechanical properties of the substrate, the metallic sheet in general, to determine the new properties of the assembly of substrate and the two coating layers, also the determination of mechanical properties of the layers. From the analysis of vibroacoustic signals obtained by the impulse excitation of the sample, one can determine the elasticity modulus. These results come to validate the results based on finite element analysis (FEA) of the same samples.

  4. Surface Coating Constraint Induced Self-Discharging of Silicon Nanoparticles as Anodes for Lithium Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Langli; Zhao, Peng; Yang, Hui; Liu, Borui; Zhang, Jiguang; Cui, Yi; Yu, Guihua; Zhang, Sulin; Wang, Chong M.

    2015-10-01

    One of the key challenges of Si-based anodes for lithium ion batteries is the large volume change upon lithiation and delithiation, which commonly leads to electrochemo-mechanical degradation and subsequent fast capacity fading. Recent studies have shown that applying nanometer-thick coating layers on Si nanoparticle (SiNPs) enhances cyclability and capacity retention. However, it is far from clear how the coating layer function from the point of view of both surface chemistry and electrochemo-mechanical effect. Herein, we use in situ transmission electron microscopy to investigate the lithiation/delithiation kinetics of SiNPs coated with a conductive polymer, polypyrrole (PPy). We discovered that this coating layer can lead to “self-delithiation” or “self-discharging” at different stages of lithiation. We rationalized that the self-discharging is driven by the internal compressive stress generated inside the lithiated SiNPs due to the constraint effect of the coating layer. We also noticed that the critical size of lithiation-induced fracture of SiNPs is increased from ~ 150 nm for bare SiNPs to ~ 380 nm for the PPy-coated SiNPs, showing a mechanically protective role of the coating layer. These observations demonstrate both beneficial and detrimental roles of the surface coatings, shedding light on rational design of surface coatings for silicon to retain high-power and high capacity as anode for lithium ion batteries.

  5. Combustion synthesis of TiB2-based cermets: modeling and experimental results

    International Nuclear Information System (INIS)

    Martinez Pacheco, M.; Bouma, R.H.B.; Katgerman, L.

    2008-01-01

    TiB 2 -based cermets are prepared by combustion synthesis followed by a pressing stage in a granulate medium. Products obtained by combustion synthesis are characterized by a large remaining porosity (typically 50%). To produce dense cermets, a subsequent densification step is performed after the combustion process and when the reacted material is still hot. To design the process, numerical simulations are carried out and compared to experimental results. In addition, physical and electrical properties of the products related to electrical contact applications are evaluated. (orig.)

  6. Induction Heating Model of Cermet Fuel Element Environmental Test (CFEET)

    Science.gov (United States)

    Gomez, Carlos F.; Bradley, D. E.; Cavender, D. P.; Mireles, O. R.; Hickman, R. R.; Trent, D.; Stewart, E.

    2013-01-01

    Deep space missions with large payloads require high specific impulse and relatively high thrust to achieve mission goals in reasonable time frames. Nuclear Thermal Rockets (NTR) are capable of producing a high specific impulse by employing heat produced by a fission reactor to heat and therefore accelerate hydrogen through a rocket nozzle providing thrust. Fuel element temperatures are very high (up to 3000 K) and hydrogen is highly reactive with most materials at high temperatures. Data covering the effects of high-temperature hydrogen exposure on fuel elements are limited. The primary concern is the mechanical failure of fuel elements due to large thermal gradients; therefore, high-melting-point ceramics-metallic matrix composites (cermets) are one of the fuels under consideration as part of the Nuclear Cryogenic Propulsion Stage (NCPS) Advance Exploration System (AES) technology project at the Marshall Space Flight Center. The purpose of testing and analytical modeling is to determine their ability to survive and maintain thermal performance in a prototypical NTR reactor environment of exposure to hydrogen at very high temperatures and obtain data to assess the properties of the non-nuclear support materials. The fission process and the resulting heating performance are well known and do not require that active fissile material to be integrated in this testing. A small-scale test bed; Compact Fuel Element Environmental Tester (CFEET), designed to heat fuel element samples via induction heating and expose samples to hydrogen is being developed at MSFC to assist in optimal material and manufacturing process selection without utilizing fissile material. This paper details the analytical approach to help design and optimize the test bed using COMSOL Multiphysics for predicting thermal gradients induced by electromagnetic heating (Induction heating) and Thermal Desktop for radiation calculations.

  7. High temperature mechanical behaviour of various cermets and hard metals; Comportement mecanique a haute temperature du metal dur et de differents cermets de coupe

    Energy Technology Data Exchange (ETDEWEB)

    Viatte, T. [Stellram SA, Nyon (Switzerland); Bolognini, S.; Feusier, G.; Benoit, W. [Ecole Polytechnique Federale, Lausanne (Switzerland); Cutard, T. [Ecole Nationale Superieure des Mines, 81 - Albi (France)

    1997-12-31

    In the course of development of new cemented carbides, the possibility to join the high toughness properties of WC-Co with the high resistance to plastic deformation of Ti(C,N)-Mo{sub 2}C-Ni cermets remains an important research axis. This paper presents some results of an ongoing project, between Stellram SA-Nyon (Switzerland) and the Swiss Federal Institute of Technology of Lausanne (Switzerland), which is directly inscribed in the field. The aim is to study the effects of several compositional parameters on the microstructure and on the high temperature mechanical behaviour of Ti(C,N)-Mo{sub 2}C-(Ni,Co) cermets and of WC-Co. Microstructures are characterized by conventional and analytical TEM observations and by complementary SEM analysis. The high temperature mechanical behaviour is investigated both by internal friction measurements and by macroscopic three point bend tests. (authors) 16 refs.

  8. Investigation on microstructure and mechanical properties of Mo2FeB2 based cermets with and without PVA

    Science.gov (United States)

    Shen, Yupeng; Huang, Zhifu; Jian, Yongxin; Yang, Ming; Li, Kemin

    2018-03-01

    Mo2FeB2 based cermets with and without PVA have been investigated by x-ray diffractometry (XRD), x-ray photoelectron spectroscope (XPS) and scanning electron microscopy (SEM). The density and transverse rupture strength (TRS) of green compact, relative density, hardness (HRA), fracture toughness (KIC) and TRS of Mo2FeB2 based cermets were also measured. The results indicate that, compared with the Mo2FeB2 based cermets without PVA, the density of green compact with PVA can be improved slightly at the same pressure. However, the much higher TRS is obtained for the green compact without PVA. Meanwhile, Mo2FeB2 particles exhibit the finer and less congruity feature for Mo2FeB2 based cermets without PVA. In addition, the higher relative density, hardness, fracture toughness and TRS can be acquired for the cermets without PVA. Obviously, considering the mechanical properties and preparation period of Mo2FeB2 based cermets, no adding PVA is the optimized process of powder molding in the manufacture of Mo2FeB2 based cermets.

  9. Microstructures of friction surfaced coatings. A TEM study; Gefuege durch Reibauftragschweissen aufgetragener Beschichtungen. Eine TEM-Untersuchung

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Javed; Kalvala, Prasad Rao; Misra, Mano [Utah Univ., Salt Lake City, UT (United States). Dept. of Metallurgical Engineering; Dilip, J. John Samuel [Louisville Univ., KY (United States). Dept. of Industrial Engineering; Pal, Deepankar; Stucker, Brent [Louisville Univ., KY (United States). Dept. of Industrial Engineering; 3D Sim, Park City, UT (United States)

    2016-05-15

    The microstructures of dissimilar metal welds between 9Cr-1Mo (Modified) (P91) and austenitic stainless steel (AISI 304) with Ni-based alloy interlayers (Inconel 625, Inconel 600 and Inconel 800H) are reported. These interlayers were deposited by the friction surfacing method one over the other on P91 alloy, which was finally friction welded to AISI 304. In this paper, the results of microstructural evolution in the friction surfaced coated interlayers (Inconel 625, 600, 800H) are reported. For comparative purposes, the microstructures of consumable rods (Inconel 625, 600, 800H) and dissimilar metal base metals (P91 and AISI 304) were also reported. Friction surfaced coatings exhibited dynamic recrystallization. In friction surfaced coatings, the carbide particles were found to be finer and distributed uniformly throughout the matrix, compared to their rod counterparts.

  10. Preparation and Mechanical Properties of TiC-Fe Cermets and TiC-Fe/Fe Bilayer Composites

    Science.gov (United States)

    Zheng, Yong; Zhou, Yang; Li, Runfeng; Wang, Jiaqi; Chen, Lulu; Li, Shibo

    2017-10-01

    TiC-Fe cermets and TiC-Fe/Fe bilayer composites consisting of a pure Fe layer and a TiC-Fe cermets layer were fabricated by hot-pressing sintering. The pure Fe layer contributes to the toughness of composites, and the TiC-Fe cermets layer endows the composites with an improved tensile strength and hardness. The effect of TiC contents (30-60 vol.%) on the mechanical properties of TiC-Fe cermets and TiC-Fe/Fe bilayer composites was investigated. Among the TiC-Fe cermets, the 40 vol.% TiC-Fe cermets possessed the highest tensile strength of 581 MPa and Vickers hardness of 5.1 GPa. The maximum fracture toughness of 17.0 MPa m1/2 was achieved for the TiC-Fe cermets with 30 vol.% TiC. For the TiC-Fe/Fe bilayer composites, the 40 vol.% TiC-Fe/Fe bilayer composite owns the maximum tensile strength of 588 MPa, which is higher than that of 40 vol.% TiC-Fe cermets. In addition, the 33.5% increment of tensile strength of 30 vol.% TiC-Fe/Fe bilayer composite comparing with the 30 vol.% TiC-Fe cermets, which is attributed to the 30 vol.% TiC-Fe/Fe bilayer composite exhibited the largest interlaminar shear strength of 335 MPa. The bilayer composites are expected to be used as wear resistance components in some heavy wear conditions.

  11. PLASMA SPRAYING OF REFRACTORY CERMETS BY THE WATER-STABILIZED SPRAY (WSP®) SYSTEM

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Brožek, V.; Cheong, D.-I.; Chráska, Pavel

    2009-01-01

    Roč. 54, č. 3 (2009), s. 241-253 ISSN 0001-7043 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma spraying * cermet coatings * microhardness * zirconium carbide * tungsten Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  12. Characterization of Nanometric-Sized Carbides Formed During Tempering of Carbide-Steel Cermets

    Directory of Open Access Journals (Sweden)

    Matus K.

    2016-06-01

    Full Text Available The aim of this article of this paper is to present issues related to characterization of nanometric-sized carbides, nitrides and/or carbonitrides formed during tempering of carbide-steel cermets. Closer examination of those materials is important because of hardness growth of carbide-steel cermet after tempering. The results obtained during research show that the upswing of hardness is significantly higher than for high-speed steels. Another interesting fact is the displacement of secondary hardness effect observed for this material to a higher tempering temperature range. Determined influence of the atmosphere in the sintering process on precipitations formed during tempering of carbide-steel cermets. So far examination of carbidesteel cermet produced by powder injection moulding was carried out mainly in the scanning electron microscope. A proper description of nanosized particles is both important and difficult as achievements of nanoscience and nanotechnology confirm the significant influence of nanocrystalline particles on material properties even if its mass fraction is undetectable by standard methods. The following research studies have been carried out using transmission electron microscopy, mainly selected area electron diffraction and energy dispersive spectroscopy. The obtained results and computer simulations comparison were made.

  13. Plasma spraying of zirconium carbide – hafnium carbide – tungsten cermets

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Ctibor, Pavel; Cheong, D.-I.; Yang, S.-H.

    2009-01-01

    Roč. 9, č. 1 (2009), s. 49-64 ISSN 1335-8987 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma spraying * cermet coatings * microhardness * zirconium carbide * hafnium carbide * tungsten * water stabilized plasma Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  14. Orientation relationship and interfaces in Ni and Co-YSZ cermets prepared from directionally solidified eutectics

    Science.gov (United States)

    Larrea, Angel; Laguna-Bercero, Miguel A.; Peña, José I.; Merino, Rosa I.; Orera, Víctor M.

    2009-06-01

    Textured Ni-YSZ and Co-YSZ (YSZ: cubic yttria stabilized zirconia) cermets prepared by reduction of directionally solidified NiO-YSZ and CoO-YSZ oxide eutectics respectively display a self-organized microstucture formed by ∼400 nm wide alternating lamellae of YSZ and porous metal suitable for electrochemical applications. The electrochemical properties of the cermets depend on their microstructure. We have analyzed the orientation relationships and interfaces both of the oxide composites and cermets using Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray pole figures and Electron Back-Scattering Diffraction. In spite of the similar crystal structure, growth habits and orientation relationships of NiO-YSZ and CoO-YSZ are different. Also the crystallographic behaviour, when cermets are produced, differs. However the metal-YSZ interfaces are about the most stable ones giving good metal-ceramic adhesion. Due to their lamellar microstructure and good metal-ceramic adhesion these composites present long-term stability at working conditions, which makes them good candidates to be used as anodes in solid oxide fuel cells or electrolyzers.

  15. Materials selection of surface coatings in an advanced size reduction facility

    International Nuclear Information System (INIS)

    Briggs, J.L.; Younger, A.F.

    1980-01-01

    A materials selection test program was conducted to characterize optimum interior surface coatings for an advanced size reduction facility. The equipment to be processed by this facility consists of stainless steel apparatus (e.g., glove boxes, piping, and tanks) used for the chemical recovery of plutonium. Test results showed that a primary requirement for a satisfactory coating is ease of decontamination. A closely related concern is the resistance of paint films to nitric acid - plutonium environments. A vinyl copolymer base paint was the only coating, of eight paints tested, with properties that permitted satisfactory decontamination of plutonium and also performed equal to or better than the other paints in the chemical resistance, radiation stability, and impact tests

  16. Nanopore surface coating delivers nanopore size and shape through conductance-based sizing.

    Science.gov (United States)

    Frament, Cameron M; Bandara, Nuwan; Dwyer, Jason R

    2013-10-09

    The performance of nanopore single-molecule sensing elements depends intimately on their physical dimensions and surface chemical properties. These factors underpin the dependence of the nanopore ionic conductance on electrolyte concentration, yet the measured, or modeled, dependence only partially illuminates the details of geometry and surface chemistry. Using the electrolyte-dependent conductance data before and after selective surface functionalization of solid-state nanopores, however, introduces more degrees of freedom and improves the performance of conductance-based nanopore characterizations. Sets of representative nanopore profiles were used to generate conductance data, and the nanopore shape and exact dimensions were identified, through conductance alone, by orders-of-magnitude reductions in the geometry optimization metrics. The optimization framework could similarly be used to evaluate the nanopore surface coating thickness.

  17. PPS-PEG surface coating to reduce thrombogenicity of small diameter ePTFE vascular grafts.

    Science.gov (United States)

    Karrer, L; Duwe, J; Zisch, A H; Khabiri, E; Cikirikcioglu, M; Napoli, A; Goessl, A; Schaffner, T; Hess, O M; Carrel, T; Kalangos, A; Hubbell, J A; Walpoth, B H

    2005-10-01

    Patency failure of small vascular synthetic grafts is still a major problem for coronary and peripheral revascularization. Thus, three new surface coatings of small synthetic grafts were tested in an acute pig model to evaluate their thrombogenicity (extracorporeal arterio-venous shunt) and in a chronic rat model to evaluate the tissue reaction they induced (subcutaneous implantation). In five domestic pigs (25-30 kg) an extracorporeal femoro-femoral arterio-venous shunt model was used. The study protocol included first a non-heparinized perfusion sequence followed by graft perfusion after 10,000 UI iv heparin. Grafts were perfused for 3 and 9 minutes. The following coatings were tested on ePTFE grafts: poly-propylene sulphide (PPS)--poly-ethylene glycol (PEG) (wet and dry applications) as well as carbon. Two sets of control were used, one dry and one wet (vehicle only). After perfusion grafts were examined by scanning electron microscopy for semi-quantitative assessment (score 0-3) of cellular and microthrombi deposition. To assess tissue compatibility, pieces of each material were implanted subcutaneously in 16 Wistar rats. At 2, 4, 8, 12 weeks four animals each were sacrificed for semi-quantitative (score 0-3) histologic evaluation of tissue reaction. In the pig model, cellular deposition and microthrombi formation increased over time. In non- heparinized animals, the coatings did not improve the surface characteristics, since they did not prevent microthrombi formation and cellular deposition. In heparinized animals, thrombogenicity was lowest in coated grafts,especially in PPS -PEG dry (pPPS-PEG dry, but this difference was not statistically significant vs.controls. In the rat model,no significant differences of the tissue reaction could be shown between materials. While all coatings failed to add any benefit for lowering tissue reaction, surface coating with PPS -PEG (dry application) reduced thrombogenicity significantly (in heparinized animals) and thus

  18. Bacteriomimetic poly-γ-glutamic acid surface coating for hemocompatibility and safety of nanomaterials.

    Science.gov (United States)

    Shim, Gayong; Kim, Dongyoon; Kim, Jinyoung; Suh, Min Sung; Kim, Youn Kyu; Oh, Yu-Kyoung

    2017-08-01

    Poly-γ-glutamic acid (PGA), a major component of the bacterial capsule, is known to confer hydrophilicity to bacterial surfaces and protect bacteria from interactions with blood cells. We tested whether applying a bacteriomimetic surface coating of PGA modulates interactions of nanomaterials with blood cells or affects their safety and photothermal antitumor efficacy. Amphiphilic PGA (APGA), prepared by grafting phenylalanine residues to PGA, was used to anchor PGA to reduced graphene oxide (rGO) nanosheets, a model of hydrophobic nanomaterials. Surface coating of rGO with bacterial capsule-like APGA yielded APGA-tethered rGO nanosheets (ArGO). ArGO nanosheets remained stable in serum over 4 weeks, whereas rGO in plain form precipitated in serum within 5 minutes. Moreover, ArGO did not interact with blood cells, whereas rGO in plain form or as a physical mixture with PGA formed aggregates with blood cells. Mice administered ArGO at a dose of 50 mg/kg showed 100% survival and no hepatic or renal toxicity. No mice survived exposure at the same dose of rGO or a PGA/rGO mixture. Following intravenous administration, ArGO showed a greater distribution to tumors and prolonged tumor retention compared with other nanosheet formulations. Irradiation with near-infrared light completely ablated tumors in mice treated with ArGO. Our results indicate that a bacteriomimetic surface modification of nanomaterials with bacterial capsule-like APGA improves the stability in blood, biocompatibility, tumor distribution, and photothermal antitumor efficacy of rGO. Although APGA was used here to coat the surfaces of rGO, it could be applicable to coat surfaces of other hydrophobic nanomaterials.

  19. Applied electric field enhances DRG neurite growth: influence of stimulation media, surface coating and growth supplements

    Science.gov (United States)

    Wood, Matthew D.; Willits, Rebecca Kuntz

    2009-08-01

    Electrical therapies have been found to aid repair of nerve injuries and have been shown to increase and direct neurite outgrowth during stimulation. This enhanced neural growth existed even after the electric field (EF) or stimulation was removed, but the factors that may influence the enhanced growth, such as stimulation media or surface coating, have not been fully investigated. This study characterized neurite outgrowth and branching under various conditions: EF magnitude and application time, ECM surface coating, medium during EF application and growth supplements. A uniform, low-magnitude EF (24 or 44 V m-1) was applied to dissociated chick embryo dorsal root ganglia seeded on collagen or laminin-coated surfaces. During the growth period, cells were either exposed to NGF or N2, and during stimulation cells were exposed to either unsupplemented media (Ca2+) or PBS (no Ca2+). Parallel controls for each experiment included cells exposed to the chamber with no stimulation and cells remaining outside the chamber. After brief electrical stimulation (10 min), neurite length significantly increased 24 h after application for all conditions studied. Of particular interest, increased stimulation time (10-100 min) further enhanced neurite length on laminin but not on collagen surfaces. Neurite branching was not affected by stimulation on any surface, and no preferential growth of neurites was noted after stimulation. Overall, the results of this report suggest that short-duration electric stimulation is sufficient to enhance neurite length under a variety of conditions. While further data are needed to fully elucidate a mechanism for this increased growth, these data suggest that one focus of those investigations should be the interaction between the growth cone and the substrata.

  20. Cermet Fuel Element (FE) on the basis of micro fuel - FE prototype for future power engineering

    International Nuclear Information System (INIS)

    Fedik, I.; Deniskin, V.; Nalivaev, V.; Gavrilin, S.

    2006-01-01

    The FE with ceramic fuel and cladding of E110 alloy under average burnup depth of 43-45MW day/kg U with providing of 3 and 4 year operation periods are used successfully in WWER. The program had been developed for improving of the fuel cycles economical indexes and for further increasing the WWER operational characteristics. In this program the reactor safety increasing has been foreseen and also the coefficient of capacity using (KIUM) at the expense of the average implement of 55-60 MW day/kg U has been achieved. The program foresees also the integration of 5-6 year fuel cycle and other developments. It is planning to solve the pointed problems with help of traditional technical solution, directed to the improving of FE with ceramic fuel. In the present paper the design-engineering and experimental development results have been presented for creation of cermet FE on the basis of micro-fuel with matrix structure (in the further -the cermet FE) for WWER. The works have been carried out over period of the last 10 years in SRI SIA 'Luch' jointly with OKB 'Gidropress', VSRINM Bochvar name, RNTs 'Kurchatovsky institute', FEI and other. During the cermet FE introduction on the basis micro fuel at the NPP, external FE construction constant is kept. That allows installation of the new active zones without any sufficient changing of reactor installations constructions. Using of cermet FE in a new generation of WWER will allow to realize its quality in large volume, in particular, to create the first hermetic contour, to simplify and to reduce the price of safety systems, automatic adjustment, radiation protection, heat transfer purity, etc. The using of cermet FE, for example, in WWER may attach to the installation the exceeded operational properties of safety in different operation conditions, manoeuvrability, vibration strength, FA life time and FE geometrical stability

  1. Neutronic calculations of AFPR-100 reactor based on Spherical Cermet Fuel particles

    International Nuclear Information System (INIS)

    Benchrif, A.; Chetaine, A.; Amsil, H.

    2013-01-01

    Highlights: • AFPR-100 reactor considered as a small nuclear reactor without on-site refueling originally based on TRISO micro-fuel element. • The AFPR-100 reactor was re-designed using the new Spherical Cermet fuel element. • The adoption of the Cermet fuel instead of TRISO fuel reduces the core lifetime operation by 3.1 equivalent full power years. • We discussed the new micro-fuel element candidate for small and medium sized reactors. - Abstract: The Atoms For Peace Reactor (AFPR-100), as a 100 MW(e) without the need of on-site refueling, was originally based on UO2 TRISO fuel coated particles embedded in a carbon matrix directly cooled by light water. AFPR-100 is considered as a small nuclear reactor without open-vessel refueling which is proposed by Pacific Northwest National Laboratory (PNNL). An account of significant irradiation swelling in the silicon carbide fission product barrier coating layer of TRISO fuel element, a Spherical Cermet Fuel element has been proposed. Indeed, the new fuel concept, which was developed by PNNL, consists of changing the pyro-carbon and ceramic coatings that are incompatible with low temperature by Zirconium. The latter was chosen to avoid any potential Wigner energy effect issues in the TRISO fuel element. Actually, the purpose of this study is to assess the goal of AFPR-100 concept using the Cermet fuel; undeniably, the fuel core lifetime prediction may be extended for reasonably long period without on-site refueling. In fact, we investigated some neutronic parameters of reactor core by the calculation code SRAC95. The results suggest that the core fuel lifetime beyond 12 equivalent full power years (EFPYs) is possible. Hence, the adoption of Cermet fuel concept shows a core lifetime decrease of about 3.1 EFPY

  2. Affordable Development and Optimization of CERMET Fuels for NTP Ground Testing

    Science.gov (United States)

    Hickman, Robert R.; Broadway, Jeramie W.; Mireles, Omar R.

    2014-01-01

    CERMET fuel materials for Nuclear Thermal Propulsion (NTP) are currently being developed at NASA's Marshall Space Flight Center. The work is part of NASA's Advanced Space Exploration Systems Nuclear Cryogenic Propulsion Stage (NCPS) Project. The goal of the FY12-14 project is to address critical NTP technology challenges and programmatic issues to establish confidence in the affordability and viability of an NTP system. A key enabling technology for an NCPS system is the fabrication of a stable high temperature nuclear fuel form. Although much of the technology was demonstrated during previous programs, there are currently no qualified fuel materials or processes. The work at MSFC is focused on developing critical materials and process technologies for manufacturing robust, full-scale CERMET fuels. Prototypical samples are being fabricated and tested in flowing hot hydrogen to understand processing and performance relationships. As part of this initial demonstration task, a final full scale element test will be performed to validate robust designs. The next phase of the project will focus on continued development and optimization of the fuel materials to enable future ground testing. The purpose of this paper is to provide a detailed overview of the CERMET fuel materials development plan. The overall CERMET fuel development path is shown in Figure 2. The activities begin prior to ATP for a ground reactor or engine system test and include materials and process optimization, hot hydrogen screening, material property testing, and irradiation testing. The goal of the development is to increase the maturity of the fuel form and reduce risk. One of the main accomplishmens of the current AES FY12-14 project was to develop dedicated laboratories at MSFC for the fabrication and testing of full length fuel elements. This capability will enable affordable, near term development and optimization of the CERMET fuels for future ground testing. Figure 2 provides a timeline of the

  3. The development of fabrication techniques for europia/iron cermet tips for coarse-control arms in DIDO and PLUTO

    International Nuclear Information System (INIS)

    Moore, D.A.; Tarrant, E.A.

    1980-11-01

    The applicability of cermet-fabrication techniques to the production of europia/iron cermets for use as coarse-control arm tips in the materials test reactors DIDO and PLUTO has been investigated. Spheroids of europia were prepared by a dry agglomeration process. These were sintered, dispersed in iron powder and pressed into plates; the plates were then sintered to densify the iron matrix. These stages were optimised to produce a strong cermet with a europia density of >= 2.75 g/cm 3 . The uniformity of distribution of the absorber particles was confirmed by radiography, and adequate neutron-absorption worth by measurements carried out in the GLEEP reactor. An outline flow sheet has been prepared for the manufacture of europia/iron cermet plates suitable for use in the tips of DIDO and PLUTO coarse-control arms. (author)

  4. Modeling and multi-objective optimization of surface roughness and productivity in dry turning of AISI 52100 steel using (TiCN-TiN coating cermet tools

    Directory of Open Access Journals (Sweden)

    Ouahid Keblouti

    2017-01-01

    Full Text Available The present work concerns an experimental study of turning with coated cermet tools with TiCN-TiN coating layer of AISI 52100 bearing steel. The main objectives are firstly focused on the effect of cutting parameters and coating material on the performances of cutting tools. Secondly, to perform a Multi-objective optimization for minimizing surface roughness (Ra and maximizing material removal rate by desirability approach. A mathematical model was developed based on the Response Surface Methodology (RSM. ANOVA method was used to quantify the cutting parameters effects on the machining surface quality and the material removal rate. The results analysis shows that the feed rate has the most effect on the surface quality. The effect of coating layers on the surface quality is also studied. It is observed that a lower surface roughness is obtained when using PVD (TiCN-TiN coated insert when compared with uncoated tool. The values of root mean square deviation and coefficient of correlation between the theoretical and experimental data are also given in this work where the maximum calculated error is 2.65 %.

  5. Zr-ZrO sub 2 cermet solar coatings designed by modelling calculations and deposited by dc magnetron sputtering

    CERN Document Server

    Zhang Qi Chu; Lee, K D; Shen, Y G

    2003-01-01

    High solar performance Zr-ZrO sub 2 cermet solar coatings were designed using a numerical computer model and deposited experimentally. The layer thickness and Zr metal volume fraction for the Zr-ZrO sub 2 cermet solar selective coatings on a Zr or Al reflector with a surface ZrO sub 2 or Al sub 2 O sub 3 anti-reflection layer were optimized to achieve maximum photo-thermal conversion efficiency at 80 deg. C under concentration factors of 1-20 using the downhill simplex method in multi-dimensions in the numerical calculation. The dielectric function and the complex refractive index of Zr-ZrO sub 2 cermet materials were calculated using Sheng's approximation. Optimization calculations show that Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coatings with two cermet layers and three cermet layers have nearly identical solar absorptance, emittance and photo-thermal conversion efficiency that are much better than those for films with one cermet layer. The optimized Al sub 2 O sub 3 /Zr-ZrO sub 2 /Al solar coating film w...

  6. Effect of TaC addition on the microstructures and mechanical properties of Ti(C, N)-based cermets

    International Nuclear Information System (INIS)

    Wu, Peng; Zheng, Yong; Zhao, Yongle; Yu, Haizhou

    2010-01-01

    The microstructures of the prepared Ti(C, N)-based cermets with various TaC additions were studied using X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Mechanical properties such as transverse rupture strength (TRS), fracture toughness (K 1C ) and hardness (HRA) were also measured. The results showed that the grain size of the cermets decreased with increasing TaC addition, but too high TaC addition resulted in agglomeration of the grains. An increasing TaC addition increased the dissolution of tungsten, titanium, molybdenum and tantalum in the binder phase. The hardness of the cermets decreased slightly with increasing TaC addition. The transverse rupture strength was the highest for the cermets with 5 wt.% TaC addition, which was characterized by fine grains, homogeneous microstructure and the moderate thickness of rim phase in the binder. The fracture toughness of the cermets with TaC addition from 0 to 5 wt.% decreased obviously, which resulting from decreased grain size. The further decreasing of fracture toughness for the cermets with 7 wt.% TaC addition was due to increased porosity and interfacial tensile stress.

  7. Surface coating-modulated toxic responses to silver nanoparticles in Wolffia globosa.

    Science.gov (United States)

    Zou, Xiaoyan; Li, Penghui; Lou, Jie; Zhang, Hongwu

    2017-08-01

    With the omnipresence of silver nanoparticles (AgNPs) in our daily consumer products, their release has raised serious concerns. However, the biochemical mechanisms by which plants counteract the toxicity of nanoparticles are largely unknown. This study investigated the exposure of aquatic Wolffia globosa to ATP-nAg (AgNPs coated with adenosine triphosphate), cit-nAg (AgNPs coated with citrate), and Ag + . Hill reaction activity was basically lost in W. globosa treated with 10mg/L ATP-nAg and Ag + , while the activity was still maintained at 38.7%-38.9% of the respective controls at 10mg/L cit-nAg. The reduction of amounts of chlorophyll and soluble protein were shown in response to the Ag stresses. This was accompanied by the accumulation of sugar in W. globosa treated with cit-nAg. By contrast, the depletion of sugar was recorded after 10mg/L ATP-nAg and Ag + treatments. The superoxide dismutase and peroxidase activities were significantly increased after exposure to 10mg/L ATP-nAg and Ag + , which did not occurred in W. globosa treated with cit-nAg. The ratio between NADPH/NADP + was higher after cit-nAg and Ag + stresses than the respective controls. The accumulation of Ag was found to increase in a concentration-dependent manner. Ag + and ATP-nAg inhibited the uptake of P and K, and promoted the uptake of Fe and Cu. In contrast, cit-nAg only promoted the uptake of Cu. Our results implied that surface coating induced different physiological responses of W. globosa to AgNPs. Based on above results, we speculated that after exposure to cit-nAg, citrate possibly could serve as the substrate for the tricarboxylic acid cycle and accumulated sugar may promote pentose phosphate pathways. For ATP-nAg treatments, ATP would act as an exogenous energy source of plant metabolisms. Our findings demonstrate that surface coating regulates the physiological responses of plants to AgNPs through distinct mechanisms. Copyright © 2017. Published by Elsevier B.V.

  8. An Overview of Current and Past W-UO[2] CERMET Fuel Fabrication Technology

    International Nuclear Information System (INIS)

    Douglas E. Burkes; Daniel M. Wachs; James E. Werner; Steven D. Howe

    2007-01-01

    Studies dating back to the late 1940s performed by a number of different organizations and laboratories have established the major advantages of Nuclear Thermal Propulsion (NTP) systems, particularly for manned missions. A number of NTP projects have been initiated since this time; none have had any sustained fuel development work that appreciably contributed to fuel fabrication or performance data from this era. As interest in these missions returns and previous space nuclear power researchers begin to retire, fuel fabrication technologies must be revisited, so that established technologies can be transferred to young researchers seamlessly and updated, more advanced processes can be employed to develop successful NTP fuels. CERMET fuels, specifically W-UO2, are of particular interest to the next generation NTP plans since these fuels have shown significant advantages over other fuel types, such as relatively high burnup, no significant failures under severe transient conditions, capability of accommodating a large fission product inventory during irradiation and compatibility with flowing hot hydrogen. Examples of previous fabrication routes involved with CERMET fuels include hot isostatic pressing (HIPing) and press and sinter, whereas newer technologies, such as spark plasma sintering, combustion synthesis and microsphere fabrication might be well suited to produce high quality, effective fuel elements. These advanced technologies may address common issues with CERMET fuels, such as grain growth, ductile to brittle transition temperature and UO2 stoichiometry, more effectively than the commonly accepted 'traditional' fabrication routes. Bonding of fuel elements, especially if the fabrication process demands production of smaller element segments, must be investigated. Advanced brazing techniques and compounds are now available that could produce a higher quality bond segment with increased ease in joining. This paper will briefly address the history of CERMET

  9. Cutting assembly

    Science.gov (United States)

    Racki, Daniel J.; Swenson, Clark E.; Bencloski, William A.; Wineman, Arthur L.

    1984-01-01

    A cutting apparatus includes a support table mounted for movement toward and away from a workpiece and carrying a mirror which directs a cutting laser beam onto the workpiece. A carrier is rotatably and pivotally mounted on the support table between the mirror and workpiece and supports a conduit discharging gas toward the point of impingement of the laser beam on the workpiece. Means are provided for rotating the carrier relative to the support table to place the gas discharging conduit in the proper positions for cuts made in different directions on the workpiece.

  10. Surface Coating of Oxide Powders: A New Synthesis Method to Process Biomedical Grade Nano-Composites

    Directory of Open Access Journals (Sweden)

    Paola Palmero

    2014-07-01

    Full Text Available Composite and nanocomposite ceramics have achieved special interest in recent years when used for biomedical applications. They have demonstrated, in some cases, increased performance, reliability, and stability in vivo, with respect to pure monolithic ceramics. Current research aims at developing new compositions and architectures to further increase their properties. However, the ability to tailor the microstructure requires the careful control of all steps of manufacturing, from the synthesis of composite nanopowders, to their processing and sintering. This review aims at deepening understanding of the critical issues associated with the manufacturing of nanocomposite ceramics, focusing on the key role of the synthesis methods to develop homogeneous and tailored microstructures. In this frame, the authors have developed an innovative method, named “surface-coating process”, in which matrix oxide powders are coated with inorganic precursors of the second phase. The method is illustrated into two case studies; the former, on Zirconia Toughened Alumina (ZTA materials for orthopedic applications, and the latter, on Zirconia-based composites for dental implants, discussing the advances and the potential of the method, which can become a valuable alternative to the current synthesis process already used at a clinical and industrial scale.

  11. Influence of Surface Coating of Magnetic Nanoparticles on Mechanical Properties of Polymer Nanocomposites

    Science.gov (United States)

    Yarar, Ecem; Karakas, Gizem; Rende, Deniz; Ozisik, Rahmi; Malta, Seyda

    Polymer nanocomposites have emerged as promising materials due to improved properties when compared with conventional bulk polymers. Nanofillers are natural or synthetic organic/inorganic particles that are less than 100 nm in at least one dimension. Even the addition of trace amounts of nanofillers to polymers may lad to unique combinations of properties. Among variety of inorganic nanofillers, iron oxide magnetic nanoparticles are of great interest due to their unique physical and chemical properties, such as low toxicity, biocompatibility, large magnetization and conductivity, owing to their extremely small size and large specific surface area. In this study, approximately 8-10 nm magnetic nanoparticles coated with either citric acid or oleic acid are synthesized and blended with poly(methyl methacrylate) (PMMA) or poly(ethylene oxide) (PEO). The hydrophobicity/hydrophillicity of the polymer and the surface coating on the iron oxide nanoparticles are exploited to control the dispersion state of nanoparticles, and the effect of dispersion on mechanical and thermal properties of the nanocomposite are investigated via experimental methods such as dynamic mechanical analysis and differential scanning calorimetry. This material is based upon work partially supported by the National Science Foundation under Grant No. CMMI-1538730 and TUBITAK 112M666.

  12. Antisoiling technology: Theories of surface soiling and performance of antisoiling surface coatings

    Science.gov (United States)

    Cuddihy, E. F.; Willis, P. B.

    1984-11-01

    Physical examination of surfaces undergoing natural outdoor soiling suggests that soil matter accumulates in up to three distinct layers. The first layer involves strong chemical attachment or strong chemisorption of soil matter on the primary surface. The second layer is physical, consisting of a highly organized arrangement of soil creating a gradation in surface energy from a high associated with the energetic first layer to the lowest possible state on the outer surfce of the second layer. The lowest possible energy state is dictated by the physical nature of the regional atmospheric soiling materials. These first two layers are resistant to removal by rain. The third layer constitutes a settling of loose soil matter, accumulating in dry periods and being removed during rainy periods. Theories and evidence suggest that surfaces that should be naturally resistant to the formation of the first two-resistant layers should be hard, smooth, hydrophobic, free of first-period elements, and have the lowest possible surface energy. These characteristics, evolving as requirements for low-soiling surfaces, suggest that surfaces or surface coatings should be of fluorocarbon chemistry. Evidence for the three-soil-layer concept, and data on the positive performance of candidate fluorocarbon coatings on glass and transparent plastic films after 28 months of outdoor exposure, are presented.

  13. Cyclic fatigue comparison among endodontic instruments with similar cross section and different surface coating.

    Science.gov (United States)

    Pedullà, Eugenio; Plotino, Gianluca; Scibilia, Mauro; Grande, Nicola M; DE Santis, Daniele; Pardo, Alessia; Testarelli, Luca; Gambarini, Gianluca

    2016-11-09

    The aim of this study was to analyze the influence of rotary instruments' geometry and surface titanium-nitride (TiN) treatment on the fatigue fracture, through the comparison of cyclic fatigue resistance of two endodontic systems that have similar cross-sectional design and different surface coating. 130 Mtwo (10/.04; 15/.05; 20/.06; 25/.06; 30/.05; 35/.04; 40/.04) and Easy Shape (15/.04; 20/.05; 25/.06; 30/.05; 35/.04; 40/.04) were tested for cyclic fatigue resistance. Time to fracture (TtF) was determined by counting the seconds of continuous rotation until final fracture in an artificial canal with 60° angle and a 5 mm radius of curve. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). Data were subjected to one-way analysis of variance (ANOVA) and Tukey post-hoc tests. Mtwo perform a significantly (P0,05). Mtwo exhibit a higher NCF thanks to the smaller metal volume contained in their core. Titanium-nitride coating doesn't influence the performance of Easy Shape instruments on static test of cyclic fatigue.

  14. Effect of Anti-Sticking Nanostructured Surface Coating on Minimally Invasive Electrosurgical Device in Brain.

    Science.gov (United States)

    Cheng, Han-Yi; Ou, Keng-Liang; Chiang, Hsi-Jen; Lin, Li-Hsiang

    2015-10-01

    The purpose of the present study was to examine the extent of thermal injury in the brain after the use of a minimally invasive electrosurgical device with a nanostructured copper-doped diamond-like carbon (DLC-Cu) surface coating. To effectively utilize an electrosurgical device in clinical surgery, it is important to decrease the thermal injury to the adjacent tissues. The surface characteristics and morphology of DLC-Cu thin film was evaluated using a contact angle goniometer, scanning electron microscopy, and atomic force microscopy. Three-dimensional biomedical brain models were reconstructed using magnetic resonance images to simulate the electrosurgical procedure. Results indicated that the temperature was reduced significantly when a minimally invasive electrosurgical device with a DLC-Cu thin film coating (DLC-Cu-SS) was used. Temperatures decreased with the use of devices with increasing film thickness. Thermographic data revealed that surgical temperatures in an animal model were significantly lower with the DLC-Cu-SS electrosurgical device compared to an untreated device. Furthermore, the DLC-Cu-SS device created a relatively small region of injury and lateral thermal range. As described above, the biomedical nanostructured film reduced excessive thermal injury with the use of a minimally invasive electrosurgical device in the brain.

  15. Physisorbed surface coatings for poly(dimethylsiloxane) and quartz microfluidic devices

    Science.gov (United States)

    Viefhues, M.; Manchanda, S.; Chao, T.-C.; Anselmetti, D.; Regtmeier, J.; Ros, A.

    2011-01-01

    Surface modifications of microfluidic devices are of essential importance for successful bioanalytical applications. Here, we investigate three different coatings for quartz and poly(dimethylsiloxane) (PDMS) surfaces. We employed a triblock copolymer with trade name F108, poly (l-lysine)-g-poly(ethylene glycol) (PLL-PEG), as well as the hybrid coating n-dodecyl-β-d-maltoside and methyl cellulose (DDM/MC). The impact of these coatings was characterized by measuring the electroosmotic flow (EOF), contact angle, and prevention of protein adsorption. Furthermore, we investigated the influence of static coatings, i.e., the incubation with the coating agent prior to measurements, and dynamic coatings, where the coating agent was present during the measurement. We found that all coatings on PDMS as well as quartz reduced EOF, increased reproducibility of EOF, reduced protein adsorption, and improved the wettability of the surfaces. Among the coating strategies tested, the dynamic coatings with DDM/MC and F108 demonstrated maximal reduction of EOF and protein adsorption and simultaneously best long-term stability concerning EOF. For PLL-PEG, a reversal in the EOF direction was observed. Interestingly, the static surface coating strategy with F108 proved to be as effective to prevent protein adsorption as dynamic coating with this block copolymer. These findings will allow optimized parameter choices for coating strategies on PDMS and quartz microfluidic devices in which control of EOF and reduced biofouling are indispensable. PMID:21847528

  16. Fundamentals of liquid phase for modern cermets and functionally graded cemented carbonitrides (FGCC)

    International Nuclear Information System (INIS)

    Chen, L.; Lengauer, W.; Ettmayer, P.; Dreyer, K.; Daub, H.W.; Kassel, D.

    2001-01-01

    Metallurgical reactions and microstructure developments during sintering of modern cermets and functionally graded cemented carbonitrides (FGCC) were investigated by modern thermal and analytical methods such as mass spectrometer (MS), differential thermal analysis (DTA), differential scanning calorimeter (DSC), dilatometer (DIL), microscopy and analytical electronic microscopy with energy dispersive spectrometer (EDS). The complex phase reactions and phase equilibrium in the multi-component system Ti/Mo/W/Ta/Nb/C,N-Co/Ni were studied. The melting behaviors in the systems of TiC-WC/MoC-Ni/Co, TiC-TiN-WC-Co and TiCN-TaC-WC-Co have been established. By better understanding of the mechanisms that govern the sintering processing and metallurgical reactions, new cermets and different types of functionally graded cemented carbonitrides (FGCC) with desired microstructures and properties were developed and fabricated. (author)

  17. Dynamic SEM wear studies of tungsten carbide cermets. [friction and wear experiments

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Dynamic friction and wear experiments were conducted in a scanning electron microscope. The wear behavior of pure tungsten carbide and composite with 6 and 15 weight percent cobalt binder was examined, and etching of the binder was done to selectively determine the role of the binder in the wear process. Dynamic experiments were conducted as the tungsten carbide (WC) and bonded WC cermet surfaces were transversed by a 50 micron radiused diamond stylus. These studies show that the predominant wear process in WC is fracture initiated by plastic deformation, and the wear of the etched cermets is similar to pure WC. The presence of the cobalt binder reduces both friction and wear. The cementing action of the cobalt reduces granular separation, and promotes a dense polished layer because of its low shear strength film-forming properties. The wear debris generated from unetched surface is approximately the same composition as the bulk.

  18. Corrosion of cermet cores of fuel plates for nuclear research reactor

    International Nuclear Information System (INIS)

    Durazzo, M.; Ramanathan, L.V.

    1984-01-01

    Materials Testing Reactor (MTR) type fuel plates containing U 3 O 8 -Al cores and clad with Al are used in various research reactor. Preliminary investigations, where in the cladding of samples was drilled to simulate conditions of rupture due to pitting attack, revealed that considerable quantities of H 2 was evolved upon exposure of the core to water. The corrosion of cermets cores of different densities was characterized as a function of H 2 evolution that revealed 3 stages. A first stage consisting of an incubation period followed by initiation of H 2 evolution, a second stage with a constant rate of H 2 evolution and a third stage with a low rate of H 2 evolution. All 3 stages were found to vary as a function of cermet density and water temperature. (Author) [pt

  19. The possible use of cermet fuel in the DIDO and PLUTO heavy-water research reactors

    International Nuclear Information System (INIS)

    Kennedy, T.D.A.

    1981-08-01

    As part of a study of the feasibility of using low-enrichment fuels in DIDO and PLUTO reactors the heat transfer and safety aspects involved in replacing the present U/AL-alloy (75% w/w U 235 ) fuel plates with U/AL-cermet (20% w/w U 235 ) plates, having the same outside dimensions to retain the same hydraulic characteristics, have been investigated. (U.K.)

  20. Attenuation of low-frequency sound in Y-Ba-Cu-O cermets

    International Nuclear Information System (INIS)

    Golev, I.M.; Ivanov, O.N.; Shushlebin, I.M.; Gridnev, S.A.; Miloshenko, V.E.

    1989-01-01

    Sound absorption is investigated in YBa 2 Cu 3 O 7± δ cermet within 10-10 3 Hz frequency range. Anomalies of Q -1 internal friction of the given compound are detected at 10,30,55,82,92 and 105K. Q -1 wide anomaly is determined within N-S transition range. It is shown that abrupt increase of Q -1 in superconducting state, caused by the effect of induction currents, occurs at presence of external magnetic fields

  1. Metal-Matrix Hardmetal/Cermet Reinforced Composite Powders for Thermal Spray

    Directory of Open Access Journals (Sweden)

    Dmitri GOLJANDIN

    2012-03-01

    Full Text Available Recycling of materials is becoming increasingly important as industry response to public demands, that resources must be preserved and environment protected. To produce materials competitive in cost with primary product, secondary producers have to pursue new technologies and other innovations. For these purposes different recycling technologies for composite materials (oxidation, milling, remelting etc are widely used. The current paper studies hardmetal/cermet powders produced by mechanical milling technology. The following composite materials were studied: Cr3C2-Ni cermets and WC-Co hardmetal. Different disintegrator milling systems for production of powders with determined size and shape were used. Chemical composition of produced powders was analysed.  To estimate the properties of recycled hardmetal/cermet powders, sieving analysis, laser granulometry and angularity study were conducted. To describe the angularity of milled powders, spike parameter–quadric fit (SPQ was used and experiments for determination of SPQ sensitivity and precision to characterize particles angularity were performed. Images used for calculating SPQ were taken by SEM processed with Omnimet Image Analyser 22. The graphs of grindability and angularity were composed. Composite powders based on Fe- and Ni-self-fluxing alloys for thermal spray (plasma and HVOF were produced. Technological properties of powders and properties of thermal sprayed coatings from studied powders were investigated. The properties of spray powders reinforced with recycled hardmetal and cermet particles as alternatives for cost-sensitive applications were demonstrated.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1348

  2. Determination of thermal conductivity from specific heat and thermal diffusivity measurements of plasma-sprayed cermets

    International Nuclear Information System (INIS)

    Roth, E.P.; Smith, M.F.

    1986-01-01

    The thermal conductivities of three plasma-sprayed cermets have been determined over the temperature range 23-630 degrees C from the measurement of the specific heat, thermal diffusivity, and density. These cermets are mixtures of Al and SiC prepared by plasma spray deposition and are being considered for various applications in magnetic confinement fusion devices. The samples consisted of three compositions: 61 vol% Al/39 vol% SiC, 74 vol% Al/26 vol% SiC, and 83 vol% Al/17 vol% SiC. The specific heat was determined by differential scanning calorimetry through the Al melt transition up to 720 0 C, while the thermal diffusivity was determined using the laser flash technique up to 630 0 C. The linear thermal expansion was measured and used to correct the diffusivity and density values. The thermal diffusivity showed a significant increase after thermal cycling due to a reduction in the intergrain contact resistance, increasing from 0.4 to 0.6 cm /SUP 2./ S -1 at 160 0 C. However, effective medium theory calculations indicated that the thermal conductivities of both the Al and the SiC were below the ideal defect-free limit even after high-temperature cycling. The specific heat measurements showed suppressed melting points in the plasmasprayed cermets. The 39 vol% SiC began a melt endotherm at 577 0 C, which peaked in the 640-650 0 C range depending on the sample thermal history. Chemical and X-ray diffraction analysis indicated the presence of free silicon in the cermet and in the SiC powder, which resulted in a eutectic Al/Si alloy

  3. Metal-Matrix Hardmetal/Cermet Reinforced Composite Powders for Thermal Spray

    OpenAIRE

    Dmitri GOLJANDIN; Heikki SARJAS; Priit KULU; Helmo KÄERDI; Valdek MIKLI

    2012-01-01

    Recycling of materials is becoming increasingly important as industry response to public demands, that resources must be preserved and environment protected. To produce materials competitive in cost with primary product, secondary producers have to pursue new technologies and other innovations. For these purposes different recycling technologies for composite materials (oxidation, milling, remelting etc) are widely used. The current paper studies hardmetal/cermet powders produced by mechanica...

  4. Characterization of nanostructured ceramic and cermet coatings deposited by plasma spraying

    OpenAIRE

    Sánchez Vilches, Enrique Javier; Bannier, Emilie; Vicent, Mónica; Moreno Berto, Arnaldo; Salvador Moya, María Dolores; Bonache Bezares, Victoria; Klyatskina, Elizabeta; Boccaccini, Aldo R.

    2011-01-01

    Industry has a growing need of advanced coatings for a variety of applications (aerospace, special machinery, medicine ...). Nanostructured coatings have the potential of providing novel materials with enhanced properties. This paper describes the results of recent research on wear resistant nanostructured coatings. Cermet (WC- Co) and ceramic (Al2O3-TiO2) coatings were obtained by atmospheric plasma spraying. Coating microstructure and phase composition were characterized using SEM, EDX and ...

  5. Microstructure and thermal conductivity of Mo-TiC cermets processed by hot isostatic pressing

    International Nuclear Information System (INIS)

    Le Flem, Marion; Allemand, Alexandre; Urvoy, Stephane; Cedat, Denis; Rey, Colette

    2008-01-01

    In the scope of refractory material development for structural applications in the core of future nuclear reactors (gas fast reactors working between 500 o C and at least 800 o C in nominal conditions and up to 1650 o C in accidental scenarios), five Mo-TiC cermets, and single-phase TiC and Mo, were processed by hot isostatic pressing. Starting TiC volume contents were 0%, 12.5%, 25%, 37.5%, 50%, 75% and 100%. First, high dense specimens were characterized in terms of microstructure, composition and phase volume fractions. Cermets exhibited two phases in agreement with phase diagram previsions (Mo-TiC 1-2at.% and TiC-Mo 10-15at.% ), and a residual non-reacted TiC-rich phase (TiC-Mo 1at.% ). Second, heat capacity and thermal diffusivity were measured up to 1000 o C which allowed to evaluate the thermal conductivity of each cermet: this lays between TiC conductivity (12-18 W/m K) and Mo conductivity (95-125 W/m K), thermal properties continuously decreasing with starting TiC content. An analytical approach based on the volume fraction and properties of each constituent allowed to highlight the existence of thermal resistance at the interphases at low temperature

  6. Demonstration of Subscale Cermet Fuel Specimen Fabrication Approach Using Spark Plasma Sintering and Diffusion Bonding

    Science.gov (United States)

    Barnes, Marvin W.; Tucker, Dennis S.; Benensky, Kelsa M.

    2018-01-01

    Nuclear thermal propulsion (NTP) has the potential to expand the limits of human space exploration by enabling crewed missions to Mars and beyond. The viability of NTP hinges on the development of a robust nuclear fuel material that can perform in the harsh operating environment (> or = 2500K, reactive hydrogen) of a nuclear thermal rocket (NTR) engine. Efforts are ongoing to develop fuel material and to assemble fuel elements that will be stable during the service life of an NTR. Ceramic-metal (cermet) fuels are being actively pursued by NASA Marshall Space Flight Center (MSFC) due to their demonstrated high-temperature stability and hydrogen compatibility. Building on past cermet fuel development research, experiments were conducted to investigate a modern fabrication approach for cermet fuel elements. The experiments used consolidated tungsten (W)-60vol%zirconia (ZrO2) compacts that were formed via spark plasma sintering (SPS). The consolidated compacts were stacked and diffusion bonded to assess the integrity of the bond lines and internal cooling channel cladding. The assessment included hot hydrogen testing of the manufactured surrogate fuel and pure W for 45 minutes at 2500 K in the compact fuel element environmental test (CFEET) system. Performance of bonded W-ZrO2 rods was compared to bonded pure W rods to access bond line integrity and composite stability. Bonded surrogate fuels retained structural integrity throughout testing and incurred minimal mass loss.

  7. Feasibility of Cathode Surface Coating Technology for High-Energy Lithium-ion and Beyond-Lithium-ion Batteries.

    Science.gov (United States)

    Kalluri, Sujith; Yoon, Moonsu; Jo, Minki; Liu, Hua Kun; Dou, Shi Xue; Cho, Jaephil; Guo, Zaiping

    2017-12-01

    Cathode material degradation during cycling is one of the key obstacles to upgrading lithium-ion and beyond-lithium-ion batteries for high-energy and varied-temperature applications. Herein, we highlight recent progress in material surface-coating as the foremost solution to resist the surface phase-transitions and cracking in cathode particles in mono-valent (Li, Na, K) and multi-valent (Mg, Ca, Al) ion batteries under high-voltage and varied-temperature conditions. Importantly, we shed light on the future of materials surface-coating technology with possible research directions. In this regard, we provide our viewpoint on a novel hybrid surface-coating strategy, which has been successfully evaluated in LiCoO 2 -based-Li-ion cells under adverse conditions with industrial specifications for customer-demanding applications. The proposed coating strategy includes a first surface-coating of the as-prepared cathode powders (by sol-gel) and then an ultra-thin ceramic-oxide coating on their electrodes (by atomic-layer deposition). What makes it appealing for industry applications is that such a coating strategy can effectively maintain the integrity of materials under electro-mechanical stress, at the cathode particle and electrode- levels. Furthermore, it leads to improved energy-density and voltage retention at 4.55 V and 45 °C with highly loaded electrodes (≈24 mg.cm -2 ). Finally, the development of this coating technology for beyond-lithium-ion batteries could be a major research challenge, but one that is viable. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Evaluation of four surface coating treatments for resin to zirconia bonding.

    Science.gov (United States)

    Liu, Dan; Pow, Edmond H N; Tsoi, James Kit-Hon; Matinlinna, Jukka P

    2014-04-01

    To compare the effects of four surface coating methods on resin to zirconia shear bond strength. Eighty pre-sintered zirconia discs were prepared and randomly divided into five study groups according to the corresponding methods of surface treatments as follows: group C (control group, fully sintered without any surface treatment), group S (fully sintered and then sandblasted with silica coated alumina powder), group G (fully sintered and then coated with glazing porcelain followed by acid etching), group Si (pre-coated with silica slurry then fully sintered), and group Z (coated with zirconia particles and then fully sintered). The observation of surface morphology and elemental composition analysis were conducted by SEM and EDX. Self-adhesive resin cement stubs (diameter 3.6mm and height 3mm) were then bonded on the zirconia discs with a cylindrical shape. Both initial and artificial aged (including 30-day water storage, thermal cycling for 3000 and 6000 cycles) shear bond strengths were then evaluated. All the tested coating methods showed significantly higher shear bond strengths than the control group, in both dry and aged conditions. Group S produced the strongest initial zirconia/resin bonding (19.7MPa) and the control group had the lowest value (8.8MPa). However, after thermal cycling, group Z exhibited the highest mean value. All the samples in the control group failed in the thermal cycling. Both different coating methods (ptreatments (pcoating might be a reliable way in enhancing adhesion between resin and zirconia. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Stress response of a clinical Enterococcus faecalis isolate subjected to a novel antimicrobial surface coating.

    Science.gov (United States)

    Clauss-Lendzian, Emanuel; Vaishampayan, Ankita; de Jong, Anne; Landau, Uwe; Meyer, Carsten; Kok, Jan; Grohmann, Elisabeth

    2018-03-01

    Emerging antibiotic resistance among pathogenic bacteria, paired with their ability to form biofilms on medical and technical devices, represents a serious problem for effective and long-term decontamination in health-care environments and gives rise to an urgent need for new antimicrobial materials. Here we present the impact of AGXX ® , a novel broad-spectrum antimicrobial surface coating consisting of micro-galvanic elements formed by silver and ruthenium, on the transcriptome of Enterococcus faecalis. A clinical E. faecalis isolate was subjected to metal stress by growing it for different periods in presence of the antimicrobial coating or silver-coated steel meshes. Subsequently, total RNA was isolated and next-generation RNA sequencing was performed to analyze variations in gene expression in presence of the antimicrobial materials with focus on known stress genes. Exposure to the antimicrobial coating had a large impact on the transcriptome of E. faecalis. After 24min almost 1/5 of the E. faecalis genome displayed differential expression. At each time-point the cop operon was strongly up-regulated, providing indirect evidence for the presence of free Ag + -ions. Moreover, exposure to the antimicrobial coating induced a broad general stress response in E. faecalis. Genes coding for the chaperones GroEL and GroES and the Clp proteases, ClpE and ClpB, were among the top up-regulated heat shock genes. Differential expression of thioredoxin, superoxide dismutase and glutathione synthetase genes indicates a high level of oxidative stress. We postulate a mechanism of action where the combination of Ag + -ions and reactive oxygen species generated by AGXX ® results in a synergistic antimicrobial effect, superior to that of conventional silver coatings. Copyright © 2017 Elsevier GmbH. All rights reserved.

  10. Evaluation of Different Single-Walled Carbon Nanotube Surface Coatings for Single-Particle Tracking Applications in Biological Environments.

    Science.gov (United States)

    Gao, Zhenghong; Danné, Noémie; Godin, Antoine Guillaume; Lounis, Brahim; Cognet, Laurent

    2017-11-16

    Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must be coated using adequate molecular moieties. Yet, the choice of the suspension agent is critical since it influences both the chemical and emission properties of the SWCNTs within their environment. Here, we compare the most commonly used surface coatings for encapsulating photoluminescent SWCNTs in the context of bio-imaging applications. To be applied as single-molecule nanoprobes, encapsulated nanotubes should display low cytotoxicity, and minimal unspecific interactions with cells while still being highly luminescent so as to be imaged and tracked down to the single nanotube level for long periods of time. We tested the cell proliferation and cellular viability of each surface coating and evaluated the impact of the biocompatible surface coatings on nanotube photoluminescence brightness. Our study establishes that phospholipid-polyethylene glycol-coated carbon nanotube is the best current choice for single nanotube tracking experiments in live biological samples.

  11. Cutting Cosmos

    DEFF Research Database (Denmark)

    Mikkelsen, Henrik Hvenegaard

    around which Bugkalot society revolves, but also a reflection on anthropological theory and writing. Focusing on the transgressive acts through which masculinity is performed, this book explores the idea of the cosmic cut, the ritual act that enables the Bugkalot man to momentarily hold still the chaotic......For the first time in over 30 years, a new ethnographic study emerges on the Bugkalot tribe, more widely known as the Ilongot of the northern Philippines. Exploring the notion of masculinity among the Bugkalot, Cutting Cosmos is not only an experimental, anthropological study of the paradoxes...

  12. Interaction of hydrogen sulfide with Zr0.92Y0.08O2-δ/40% Ni cermet

    International Nuclear Information System (INIS)

    Siriwardane, R.V.; Poston, J.A. Jr.; Fisher, E.P.

    2005-01-01

    The interaction of hydrogen sulfide with a cermet composed of zirconium oxide and yttrium oxide doped with metallic nickel (Ni) in the stoichiometric form Zr 0.92 Y 0.08 O 2-δ /40 vol% Ni and a pure nickel metal was studied at 500 and 650 deg. C utilizing high temperature X-ray photoelectron spectroscopy and high-temperature scanning electron microscopy. The hydrogen sulfide (H 2 S) did not appear to interact with the cermet at 500 deg. C with H 2 S exposures of 6 x 10 -5 Torr for 1 h, but interaction of H 2 S with the cermet was observed at 650 deg. C at similar H 2 S exposures. The amount and the rate of reaction of H 2 S were significantly lower with the cermet than with the pure nickel metal at 650 deg. C with similar H 2 S exposures. The dispersion of nickel in the zirconium and yttrium oxide matrix decreased the reaction of H 2 S with nickel in the cermet

  13. Wear Resistant Thermal Sprayed Composite Coatings Based on Iron Self-Fluxing Alloy and Recycled Cermet Powders

    Directory of Open Access Journals (Sweden)

    Heikki SARJAS

    2012-03-01

    Full Text Available Thermal spray and WC-Co based coatings are widely used in areas subjected to abrasive wear. Commercial  cermet thermal spray powders for HVOF are relatively expensive. Therefore applying these powders in cost-sensitive areas like mining and agriculture are hindered. Nowadays, the use of cheap iron based self-fluxing alloy powders for thermal spray is limited. The aim of this research was to study properties of composite powders based on self-fluxing alloys and recycled cermets and to examine the properties of thermally sprayed (HVOF coatings from composite powders based on iron self-fluxing alloy and recycled cermet powders (Cr3C2-Ni and WC-Co. To estimate the properties of  recycled cermet powders, the sieving analysis, laser granulometry and morphology were conducted. For deposition of coatings High Velocity Oxy-Fuel spray was used. The structure and composition of powders and coatings were estimated by SEM and XRD methods. Abrasive wear performance of coatings was determined and compared with wear resistance of coatings from commercial powders. The wear resistance of thermal sprayed coatings from self-fluxing alloy and recycled cermet powders at abrasion is comparable with wear resistance of coatings from commercial expensive spray powders and may be an alternative in tribological applications in cost-sensitive areas.DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1338

  14. Biological effects of carbon black nanoparticles are changed by surface coating with polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Lindner, Karina; Ströbele, Michael; Schlick, Sandra; Webering, Sina; Jenckel, André; Kopf, Johannes; Danov, Olga; Sewald, Katherina; Buj, Christian; Creutzenberg, Otto; Tillmann, Thomas; Pohlmann, Gerhard; Ernst, Heinrich; Ziemann, Christina; Hüttmann, Gereon; Heine, Holger; Bockhorn, Henning; Hansen, Tanja; König, Peter; Fehrenbach, Heinz

    2017-03-21

    Carbon black nanoparticles (CBNP) are mainly composed of carbon, with a small amount of other elements (including hydrogen and oxygen). The toxicity of CBNP has been attributed to their large surface area, and through adsorbing intrinsically toxic substances, such as polycyclic aromatic hydrocarbons (PAH). It is not clear whether a PAH surface coating changes the toxicological properties of CBNP by influencing their physicochemical properties, through the specific toxicity of the surface-bound PAH, or by a combination of both. Printex ® 90 (P90) was used as CBNP; the comparators were P90 coated with either benzo[a]pyrene (BaP) or 9-nitroanthracene (9NA), and soot from acetylene combustion that bears various PAHs on the surface (AS-PAH). Oxidative stress and IL-8/KC mRNA expression were determined in A549 and bronchial epithelial cells (16HBE14o-, Calu-3), mouse intrapulmonary airways and tracheal epithelial cells. Overall toxicity was tested in a rat inhalation study according to Organization for Economic Co-operation and Development (OECD) criteria. Effects on cytochrome monooxygenase (Cyp) mRNA expression, cell viability and mucociliary clearance were determined in acute exposure models using explanted murine trachea. All particles had similar primary particle size, shape, hydrodynamic diameter and ζ-potential. All PAH-containing particles had a comparable specific surface area that was approximately one third that of P90. AS-PAH contained a mixture of PAH with expected higher toxicity than BaP or 9NA. PAH-coating reduced some effects of P90 such as IL-8 mRNA expression and oxidative stress in A549 cells, granulocyte influx in the in vivo OECD experiment, and agglomeration of P90 and mucus release in the murine trachea ex vivo. Furthermore, P90-BaP decreased particle transport speed compared to P90 at 10 μg/ml. In contrast, PAH-coating induced IL-8 mRNA expression in bronchial epithelial cell lines, and Cyp mRNA expression and apoptosis in tracheal epithelial

  15. Creep of MDF panels under constant load and cyclic environmental conditions. Influence of surface coating

    Directory of Open Access Journals (Sweden)

    Fernández-Golfín, J. I.

    1997-06-01

    Full Text Available Four different strategies of surface coating (based on 80 g m2 melamin impregnated papers were used on 19 mm thick commercial MDF panels to assess its reological behaviour under cyclic humidity conditions (20ºC 30 % rh-20ºC 90 % rh. Three different levels of stress (20 %, 30 % and 40 %, based on the ultimate load in bending, were used. Tests were conducted by means of the three points load system. For the same stress level, the relative creep of MDF panels was higher than that in particle boards with similar characteristics. This behaviour was just the opposite than the one exhibited by the panels when the comparison is made based on the same level of load (kg Melamin coating seems to strongly influence the creep behaviour of the raw material, especially when surface and edge coating were combined.

    Cuatro tipos de acabados superficiales distintos, aplicados sobre tableros MDF comerciales de 19 mm de espesor, son empleados en el estudio del comportamiento reológico de los tableros MDF ante condiciones alternantes de humedad relativa (20ºC/30 % hr-20ºC/90 % hr. Para el análisis del comportamiento reológico de los tableros se consideran tres niveles de tensión distintos (20 %, 30 %y 40 %, calculados en función de la carga última de rotura a flexión. Los ensayos son efectuados aplicando la carga en punto medio. La fluencia relativa de los tableros MDF resulta ser superior a la exhibida por los tableros de partículas de similares características, observándose que los revestimientos melamínicos aplicados superficialmente influyen eficazmente en la mejora de su comportamiento reológico. Cuando la comparación entre tableros MDF y de partículas se efectúa considerando idénticos niveles de carga aplicada en vez de tensión, el resultado de la comparación resulta ser, justamente, el contrario.

  16. Spark Plasma Sintering of Load-Bearing Iron-Carbon Nanotube-Tricalcium Phosphate CerMets for Orthopaedic Applications

    Science.gov (United States)

    Montufar, Edgar B.; Horynová, Miroslava; Casas-Luna, Mariano; Diaz-de-la-Torre, Sebastián; Celko, Ladislav; Klakurková, Lenka; Spotz, Zdenek; Diéguez-Trejo, Guillermo; Fohlerová, Zdenka; Dvorak, Karel; Zikmund, Tomáš; Kaiser, Jozef

    2016-04-01

    Recently, ceramic-metallic composite materials (CerMets) have been investigated for orthopaedic applications with promising results. This first generation of bio-CerMets combine the bioactivity of hydroxyapatite with the mechanical stability of titanium to fabricate bioactive, tough and biomechanically more biocompatible osteosynthetic devices. Nonetheless, these first CerMets are not biodegradable materials and a second surgery is required to remove the implant after bone healing. The present work aims to develop the next generation bio-CerMets, which are potential biodegradable materials. The process to produce the new biodegradable CerMet consisted of mixing powder of soluble and osteoconductive alpha tricalcium phosphate with biocompatible and biodegradable iron with consolidation through spark plasma sintering (SPS). The microstructure, composition and mechanical strength of the new CerMet were studied by metallography, x-ray diffraction and diametral tensile strength tests, respectively. The results show that SPS produces CerMet with higher mechanical performance (120 MPa) than the ceramic component alone (29 MPa) and similar mechanical strength to the pure metallic component (129 MPa). Nonetheless, although a short sintering time (10 min) was used, partial transformation of the alpha tricalcium phosphate into its allotropic and slightly less soluble beta phase was observed. Cell adhesion tests show that osteoblasts are able to attach to the CerMet surface, presenting spread morphology regardless of the component of the material with which they are in contact. However, the degradation process restricted to the small volume of the cell culture well quickly reduces the osteoblast viability.

  17. On the processing, microstructure, mechanical and wear properties of cermet/stainless steel layer composites

    International Nuclear Information System (INIS)

    Farid, Akhtar; Guo Shiju

    2007-01-01

    This study deals with layer composites of carbide reinforcements and stainless steel prepared successfully by powder technology. The layer material consisted of two layers. The top layer consisted of reinforcements (TiC and NbC) and 465 stainless steel as the binder material for the carbides. The bottom layer was entirely of binder material (465 stainless steel). The microstructure of the composite was characterized by scanning electron microscopy. The microstructural study revealed that the top layer (TiC-NbC/465 stainless steel) showed the typical core-rim microstructure of conventional steel bonded cermets and the bottom layer showed the structure of sintered steel. An intermediate layer was found with a gradient microstructure, having a higher carbide content towards the cermet layer and lower carbide content towards the stainless steel layer. The bending strength of the layered material measured in the direction perpendicular to the layer alignment was remarkably high. The variation of strength as a function of the thickness of the bottom layer revealed that the character of the material changed from the cermet, to a layer composite and then towards metallic materials. The wear resistance of the top layer was studied against high speed steel. The wear mechanisms were discussed by means of microscopical observations on the worn surfaces. The wear was severe at higher wear loads and lower TiC content. Microploughing of the stainless steel matrix was found to be the dominant wear mechanism. Heavy microploughing and rapid removal of material from the wear surface was observed at high wear load. The fracture morphologies of the top, bottom and intermediate layers are reported

  18. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 - O2 environment

    Science.gov (United States)

    Farrokhzad, M. A.; Khan, T. I.

    2014-06-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al2O3 and TiO2) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO2, 10% O2 and 75% N2. This research investigates the effects of CO2 and O2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings.

  19. The anomalous behaviour of Ag-Al sub 2 O sub 3 Cermet electroformed devices

    CERN Document Server

    Khan, M S R

    2003-01-01

    Cermet coating consisting of silver particles in an aluminium oxide matrix were prepared on glass substrates by vacuum deposition. Variation of the circulating current with potential difference was obtained in evaporated Al/Ag-Al sub 2 O sub 3 /Cu sandwich structures, 100 to 200 nm thick containing 10 wt % Ag. It was observed that the investigated sandwich structures exhibit anomalous behaviour such as electroforming with Voltage-Controlled-Negative Resistance (VCNR) in vacuo of approx 4 x 10 sup - sup 6 torr. The formed characteristics were explained on the basis of filamentary model.

  20. A review on the importance of surface coating of micro/nano-mold in micro/nano-molding processes

    International Nuclear Information System (INIS)

    Saha, Biswajit; Lee, Junghoon; Toh, Wei Quan; Liu, Erjia; Tor, Shu Beng; Hardt, David E

    2016-01-01

    Micro/nano hot-embossing and injection molding are two promising manufacturing processes for the mass production of workpieces bearing micro/nanoscale features. However, both the workpiece and micro/nano-mold are susceptive to structural damage due to high thermal stress, adhesion and friction, which occur at the interface between the workpiece and the mold during these processes. Hence, major constraints of micro/nano-molds are mainly attributed to improper replication and their inability to withstand a prolonged sliding surface contact because of high sidewall friction and/or high adhesion. Consequently, there is a need for proper surface coating as it can improve the surface properties of micro/nano-molds such as having a low friction coefficient, low adhesion and low wear rate. This review deals with the physical, mechanical and tribological properties of various surface coatings and their impact on the replication efficiency and lifetime of micro/nano-molds that are used in micro/nano hot-embossing and injection molding processes. (topical review)

  1. Powder Processing of High Temperature Cermets and Carbides at Marshall Space Flight Center

    Science.gov (United States)

    Salvail, Pat; Panda, Binayak; Hickman, Robert R.

    2007-01-01

    The Materials and Processing Laboratory at NASA Marshall Space Flight Center is developing Powder Metallurgy (PM) processing techniques for high temperature cermet and carbide material consolidation. These new group of materials would be utilized in the nuclear core for Nuclear Thermal Rockets (NTR). Cermet materials offer several advantages for NTR such as retention of fission products and fuels, better thermal shock resistance, hydrogen compatibility, high thermal conductivity, and high strength. Carbide materials offer the highest operating temperatures but are sensitive to thermal stresses and are difficult to process. To support the effort, a new facility has been setup to process refractory metal, ceramic, carbides and depleted uranium-based powders. The facility inciudes inert atmosphere glove boxes for the handling of reactive powders, a high temperature furnace, and powder processing equipment used for blending, milling, and sieving. The effort is focused on basic research to identify the most promising compositions and processing techniques. Several PM processing methods including Cold and Hot Isostatic Pressing are being evaluated to fabricate samples for characterization and hot hydrogen testing.

  2. Optimizing the vacuum plasma spray deposition of metal, ceramic, and cermet coatings using designed experiments

    Science.gov (United States)

    Kingswell, R.; Scott, K. T.; Wassell, L. L.

    1993-06-01

    The vacuum plasma spray (VPS) deposition of metal, ceramic, and cermet coatings has been investigated using designed statistical experiments. Processing conditions that were considered likely to have a significant influence on the melting characteristics of the precursor powders and hence deposition efficiency were incorporated into full and fractional factorial experimental designs. The processing of an alumina powder was very sensitive to variations in the deposition conditions, particularly the injection velocity of the powder into the plasma flame, the plasma gas composition, and the power supplied to the gun. Using a combination of full and fractional factorial experimental designs, it was possible to rapidly identify the important spraying variables and adjust these to produce a deposition efficiency approaching 80 percent. The deposition of a nickel-base alloy metal powder was less sensitive to processing conditions. Generally, however, a high degree of particle melting was achieved for a wide range of spray conditions. Preliminary experiments performed using a tungsten carbide/cobalt cermet powder indicated that spray efficiency was not sensitive to deposition conditions. However, microstructural analysis revealed considerable variations in the degree of tungsten carbide dissolution. The structure and properties of the optimized coatings produced in the factorial experiments are also discussed.

  3. Textured cermets of CeO{sub 2} (or GDC) with Co for solid oxide fuel cells anodes

    Energy Technology Data Exchange (ETDEWEB)

    Ortega-San-Martin, Luis; Pena, Jose Ignacio; Larrea, Angel; Gil, Vanesa; Orera, Victor M. [Instituto de Ciencia de Materiales de Aragon, CSIC-Universidad de Zaragoza, Fac de Ciencias, C/ Pedro Cerbuna 12, 50009-Zaragoza (Spain)

    2010-10-15

    Cermets composed of submicron size alternating lamellae of CeO{sub 2}, or 10% Gadolinia doped Ceria (GDC), and porous-metallic Cobalt have been prepared from eutectic oxide mixtures. A fine eutectic structure was obtained by fast directional solidification of the cobalt oxide-ceria oxide eutectic composite using the Laser Floating Zone (LFZ) technique. The resulting microstructure, with an interphase spacing down to 0.5 {mu}m, was obtained for solidification rates of 750 mm/h. Textured cermets were obtained by subsequent reduction under H{sub 2} containing atmosphere of the eutectic oxide composite. The reduction kinetics was studied in the 550-750 C temperature range and effective diffusion coefficients were obtained. The reduction process does not correspond to a typical thermally activated process. The cermets are composed of ceria lamellae of about 200 nm thickness alternated with porous-metallic cobalt lamellae of {<=}400 nm. The lamellar microstructure of the cermets favours oxygen ion mobility through ceria and its size can be controlled by solidification rate of the eutectic precursor. These materials are proposed as SOFC anodes. (author)

  4. Fabrication method of low f-number microlens arrays by using surface coating and epoxy dispensing technology

    Science.gov (United States)

    Li, Pei; Pei, Jing; Pan, Long-fa; Zappe, Hans

    2014-04-01

    We describe a fabrication method for arrays of microlenses of low f-number by using a surface coating and dispensing technology. We demonstrate how to achieve a low f-number by selectively changing the surface wettability, as well as how to precisely control the f-number through control of the dispensing time. This advance enables the fabrication of arrays of microlenses with diameters varying from 400 to 1400 μm, f-number as low as 0.95. In addition, the optical performance tests indicate that this method is suitable for high performance microlens array fabrication. This dispensing technology may be low cost and allow fast fabrication of high-speed microlens arrays, and may thus be particularly useful for biologically inspired advanced optical systems.

  5. The immobilization of a direct thrombin inhibitor to a polyurethane as a nonthrombogenic surface coating for extracorporeal circulation

    Science.gov (United States)

    Yu, Jane; Brisbois, Elizabeth; Handa, Hitesh; Annich, Gail; Meyerhoff, Mark; Bartlett, Robert; Major, Terry

    2016-01-01

    A biomaterial with both antithrombin and antiplatelet properties is the ideal surface for use in extracorporeal circulation (ECC) as it targets both fibrin generation and platelet adhesion. A hemocompatible surface coating avoids the need for systemic anticoagulation by providing a local anticoagulant effect at the polymer-blood interface. Previous work has demonstrated the potential use of argatroban, a direct thrombin inhibitor, as a nonthrombogenic material for extracorporeal devices. The work reported here focuses on the characterization of argatroban linked to a polyurethane-silicone polymer, CarboSil®. Chemical immobilization, the amount of argatroban, incubation times, and saturation point were evaluated to achieve maximal antithrombin activity at the polymer surface. Cross-linked polymer coatings reacted with 10 and 30 µmole of argatroban were prepared and tested. These coatings resulted in argatroban activity levels of 0.131 µM and 0.446 µM, respectively. After refining the cross-linking process, argatroban activity increased by approximately 3.6 fold. Maintenance of activity and leaching from the polymer surface were also evaluated. Using the refined process for linking argatroban to polymer, the resulting polymer was applied as a surface coating to the inner lumen of poly(vinyl chloride) ECC circuit tubing and its antithrombin effect evaluated using a 4 h rabbit ECC model. Following 4 h of blood exposure, the argatroban circuit demonstrated significantly less thrombus formation compared to the control CarboSil® coating with a 4.1 cm2 thrombus average area for the control coating compared to 1.2 cm2 for the argatroban coating (n=4). There was no significant change in thrombin time from baseline in plasma from animals in which the argatroban coated circuit was used, with a thrombin time of 16.2 s at t=0 and 14.5 s after 4 h. These results demonstrate the potential efficacy of immobilized argatroban as a hemocompatible biomaterial for extracorporeal

  6. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment.

    Science.gov (United States)

    Ellis, Laura-Jayne A; Valsami-Jones, Eugenia; Lead, Jamie R; Baalousha, Mohammed

    2016-10-15

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water - MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV-visible spectrometry (UV-vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96h (4days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Rutile TiO₂ particles exert size and surface coating dependent retention and lesions on the murine brain.

    Science.gov (United States)

    Zhang, Lili; Bai, Ru; Li, Bai; Ge, Cuicui; Du, Jiangfeng; Liu, Ying; Le Guyader, Laurent; Zhao, Yuliang; Wu, Yanchuan; He, Shida; Ma, Yongmei; Chen, Chunying

    2011-11-10

    The rising commercial use and large-scale production of engineered nanoparticles (NPs) may lead to unintended exposure to humans. The central nervous system (CNS) is a potential susceptible target of the inhaled NPs, but so far the amount of studies on this aspect is limited. Here, we focus on the potential neurological lesion in the brain induced by the intranasally instilled titanium dioxide (TiO₂) particles in rutile phase and of various sizes and surface coatings. Female mice were intranasally instilled with four different types of TiO₂ particles (i.e. two types of hydrophobic particles in micro- and nano-sized without coating and two types of water-soluble hydrophilic nano-sized particles with silica surface coating) every other day for 30 days. Inductively coupled plasma mass spectrometry (ICP-MS) were used to determine the titanium contents in the sub-brain regions. Then, the pathological examination of brain tissues and measurements of the monoamine neurotransmitter levels in the sub-brain regions were performed. We found significant up-regulation of Ti contents in the cerebral cortex and striatum after intranasal instillation of hydrophilic TiO₂ NPs. Moreover, TiO₂ NPs exposure, in particular the hydrophilic NPs, caused obvious morphological changes of neurons in the cerebral cortex and significant disturbance of the monoamine neurotransmitter levels in the sub-brain regions studied. Thus, our results indicate that the surface modification of the NPs plays an important role on their effects on the brain. In addition, the difference in neurotoxicity of the two types of hydrophilic NPs may be induced by the shape differences of the materials. The present results suggest that physicochemical properties like size, shape and surface modification of the nanomaterials should be considered when evaluating their neurological effects. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  8. Faradaic current in different mullite materials. Single crystal, ceramic and cermets

    Energy Technology Data Exchange (ETDEWEB)

    Mata-Osoro, Gustavo; Moya, Jose S.; Pecharroman, Carlos [Instituto de Ciencia de Materiales de Madrid (CSIC) (Spain); Morales, Miguel [Universidad de Santiago de Compostela (Spain). LabCaF; Diaz, L. Antonio [Centro de Investigacion en Nanomateriales y Nanotecnologia (CINN-CSIC), Llanera (Spain); Schneider, Hartmut [Koeln Univ. (Germany). Inst. fuer Kristallographie

    2012-04-15

    Faradaic current measurements have been carried out on three different types of mullite: 2: 1 mullite single crystals (E perpendicular to c), 3: 2 ceramics and 11 % mullite/Mo composites. Measurements were carried out on very thin samples (60 {mu}m) at high voltages (500 to 1 000 V). Under these conditions, measurable currents were recorded even at room temperature. Results indicate notable differences between these three samples, which suggest that, although they share the same name and similar crystalline structure, binding energies and defect distributions seem to be very different. Finally, it has been seen that the excellent behaviour against dielectric breakdown of ceramic mullite does not hold for single crystals or mullite based cermets. (orig.)

  9. Boron-carbide-aluminum and boron-carbide-reactive metal cermets

    Science.gov (United States)

    Halverson, Danny C.; Pyzik, Aleksander J.; Aksay, Ilhan A.

    1986-01-01

    Hard, tough, lightweight boron-carbide-reactive metal composites, particularly boron-carbide-aluminum composites, are produced. These composites have compositions with a plurality of phases. A method is provided, including the steps of wetting and reacting the starting materials, by which the microstructures in the resulting composites can be controllably selected. Starting compositions, reaction temperatures, reaction times, and reaction atmospheres are parameters for controlling the process and resulting compositions. The ceramic phases are homogeneously distributed in the metal phases and adhesive forces at ceramic-metal interfaces are maximized. An initial consolidation step is used to achieve fully dense composites. Microstructures of boron-carbide-aluminum cermets have been produced with modulus of rupture exceeding 110 ksi and fracture toughness exceeding 12 ksi.sqroot.in. These composites and methods can be used to form a variety of structural elements.

  10. Multidisciplinary Simulation of Graphite-Composite and Cermet Fuel Elements for NTP Point of Departure Designs

    Science.gov (United States)

    Stewart, Mark E.; Schnitzler, Bruce G.

    2015-01-01

    This paper compares the expected performance of two Nuclear Thermal Propulsion fuel types. High fidelity, fluid/thermal/structural + neutronic simulations help predict the performance of graphite-composite and cermet fuel types from point of departure engine designs from the Nuclear Thermal Propulsion project. Materials and nuclear reactivity issues are reviewed for each fuel type. Thermal/structural simulations predict thermal stresses in the fuel and thermal expansion mis-match stresses in the coatings. Fluid/thermal/structural/neutronic simulations provide predictions for full fuel elements. Although NTP engines will utilize many existing chemical engine components and technologies, nuclear fuel elements are a less developed engine component and introduce design uncertainty. Consequently, these fuel element simulations provide important insights into NTP engine performance.

  11. Self Harm - Cutting

    Science.gov (United States)

    ... a sign that your child has thoughts of suicide. If you are concerned your child is cutting, learn the warning signs, methods of ... your child’s risk of cutting. While thoughts of suicide aren’t common with cutting, your child could accidentally cut deep enough or cut an ...

  12. Plasma arc cutting: speed and cut quality

    International Nuclear Information System (INIS)

    Nemchinsky, V A; Severance, W S

    2009-01-01

    When cutting metal with plasma arc cutting, the walls of the cut are narrower at the bottom than at the top. This lack of squareness increases as the cutting speed increases. A model of this phenomenon, affecting cut quality, is suggested. A thin liquid layer, which separates the plasma from the solid metal to be melted, plays a key role in the suggested model. This layer decreases heat transfer from the plasma to the solid metal; the decrease is more pronounced the higher the speed and the thicker the liquid metal layer. Since the layer is thicker at the bottom of the cut, the heat transfer effectiveness is lower at the bottom. The decrease in heat transfer effectiveness is compensated by the narrowness of the cut. The suggested model allows one to calculate the profile of the cut. The result of the calculations of the cutting speeds for plates of various thicknesses, at which the squareness of the cut is acceptable, agrees well with the speeds recommended by manufacturers. The second effect considered in the paper is the deflection of the plasma jet from the vertical at a high cutting speed. A qualitative explanation of this phenomenon is given. We believe the considerations of this paper are pertinent to other types of cutting with moving heat sources.

  13. Online Coupling of Flow-Field Flow Fractionation and Single Particle Inductively Coupled Plasma-Mass Spectrometry: Characterization of Nanoparticle Surface Coating Thickness and Aggregation State

    Science.gov (United States)

    Surface coating thickness and aggregation state have strong influence on the environmental fate, transport, and toxicity of engineered nanomaterials. In this study, flow-field flow fractionation coupled on-line with single particle inductively coupled plasma-mass spectrometry i...

  14. Li3PO4 surface coating on Ni-rich LiNi0.6Co0.2Mn0.2O2 by a citric acid assisted sol-gel method: Improved thermal stability and high-voltage performance

    Science.gov (United States)

    Lee, Suk-Woo; Kim, Myeong-Seong; Jeong, Jun Hui; Kim, Dong-Hyun; Chung, Kyung Yoon; Roh, Kwang Chul; Kim, Kwang-Bum

    2017-08-01

    A surface coating of Li3PO4 was applied to a Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM) material to improve its thermal stability and electrochemical properties via a citric acid assisted sol-gel method. The addition of citric acid effectively suppressed the instant formation of Li3PO4 in solution, resulting in successful coating of the NCM surface. The improved thermal stability of NCM after Li3PO4 surface coating was demonstrated by differential scanning calorimetry (DSC) analysis and in situ time-resolved X-ray diffraction (TR-XRD). In particular, the TR-XRD results showed that the improved thermal stability after Li3PO4 surface coating originates from suppression of the phase transition of charged NCM at high temperatures. Furthermore, the charge-discharge tests demonstrated that Li3PO4-coated LiNi0.6Co0.2Mn0.2O2 (LP-NCM) has excellent electrochemical properties. LP-NCM exhibited a specific capacity of 192.7 mAh g-1, a capacity retention of 44.1% at 10 C, and a capacity retention of 79.7% after 100 cycles at a high cut-off voltage of 4.7 V; these values represent remarkably improved electrochemical properties compared with those of bare NCM. These improved thermal and electrochemical properties were mainly attributed to the improvement of the structural stability of the material and the suppression of the interface reaction between the cathode and the electrolyte owing to the Li3PO4 coating.

  15. Structural Characteristics and Magnetic Properties of Al2O3 Matrix-Based Co-Cermet Nanogranular Films

    Directory of Open Access Journals (Sweden)

    Giap Van Cuong

    2015-01-01

    Full Text Available Magnetic micro- and nanogranular materials prepared by different methods have been used widely in studies of magnetooptical response. However, among them there seems to be nothing about magnetic nanogranular thin films prepared by a rf cosputtering technique for both metals and insulators till now. This paper presented and discussed preparation, structural characteristics, and magnetic properties of alumina (Al2O3 matrix-based granular Co-cermet thin films deposited by means of the cosputtering technique for both Co and Al2O3. By varying the ferromagnetic (Co atomic fraction, x, from 0.04 to 0.63, several dominant features of deposition for these thin films were shown. Structural characteristics by X-ray diffraction confirmed a cermet-type structure for these films. Furthermore, magnetic behaviours presented a transition from paramagnetic- to superparamagnetic- and then to ferromagnetic-like properties, indicating agglomeration and growth following Co components of Co clusters or nanoparticles. These results show a typical granular Co-cermet feature for the Co-Al2O3 thin films prepared, in which Co magnetic nanogranules are dispersed in a ceramic matrix. Such nanomaterials can be applied suitably for our investigations in future on the magnetooptical responses of spinplasmonics.

  16. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Laura-Jayne A.; Valsami-Jones, Eugenia [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lead, Jamie R., E-mail: Jlead@mailbox.sc.edu [School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia 29208 (United States); Baalousha, Mohammed, E-mail: Mbaalous@mailbox.sc.edu [Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia 29208 (United States)

    2016-10-15

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water – MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV–visible spectrometry (UV–vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28 days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96 h (4 days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. - Highlights: • Aquatic microcosms were used to study the transport and behavior of AgNPs • Experiments were conducted in low

  17. Impact of surface coating and environmental conditions on the fate and transport of silver nanoparticles in the aquatic environment

    International Nuclear Information System (INIS)

    Ellis, Laura-Jayne A.; Valsami-Jones, Eugenia; Lead, Jamie R.; Baalousha, Mohammed

    2016-01-01

    The role of surface coating (polyvinylpyrrolidone (PVP) and citrate) and water chemistry on the fate and behavior of AgNPs in aquatic microcosms is reported in this study. The migration and transformation of the AgNPs was examined in low (ultrapure water-UPW) and high ionic strength (moderately hard water – MHW) preparations, and in the presence of modeled natural organic matter (NOM) of Suwannee River Fulvic Acid (SRFA). The migration and fate of the AgNPs in the microcosms was validated using a sedimentation-diffusion model and the aggregation behavior was monitored by UV–visible spectrometry (UV–vis). Dissolved and particulate Ag concentrations (% Ag) were analyzed by ultrafiltration methods. Imaging of the AgNPs was captured using transmission electron microscopy (TEM). Results indicate that PVP-coated AgNPs (PVP-AgNPs) remained stable for 28 days with similarly distributed concentrations of the PVP-AgNPs throughout the columns in each of the water conditions after approximately 96 h (4 days). The sedimentation-diffusion model confirmed PVP-AgNP stability in each condition, by showing diffusion dominated transport by using the original unaltered AgNP sizes to fit the parameters. In comparison, citrate AgNPs were largely unstable in the more complex water preparations (MHW). In MHW, aggregation dominated behavior followed by sedimentation/dissolution controlled transport was observed. The addition of SRFA to MHW resulted in small stabilizing effects, to the citrate coated AgNPs, producing smaller sized AgNPs (TEM) and mixed sedimentation and diffusion migration compared the studies absent of SRFA. The results suggest that surface coating and solution chemistry has a major impact on AgNP stability, furthermore the corresponding modeling will support the experimental understanding of the overall fate of AgNPs in the environment. - Highlights: • Aquatic microcosms were used to study the transport and behavior of AgNPs • Experiments were conducted in low

  18. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...

  19. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    KAUST Repository

    Louie, Jennifer Sarah

    2011-02-01

    The application of polymer surface coatings to improve the fouling resistance of reverse osmosis membranes tends to increase flow resistance across the membrane. This paper presents a systematic analysis on how membrane properties and performance are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux, which is attributed to wetting of pores in the selective polyamide layer and to changes in the polymer structure. This flux increase was not readily reversible, based on a 300-h water permeation test. Conversely, drying a wetted membrane led to a decrease in water flux, which we hypothesize is caused by increased interchain hydrogen-bonding in the selective layer. This drop in water flux was not permanent; higher flux was observed if the same wetted/dried membrane was then re-soaked in ethanol prior to the water permeation experiment. An ethanol pre-soaking step also increased water flux of a PEBAX-coated membrane by nearly 70%. In contrast to the reduction in water flux caused by the specific treatment sequence of ethanol-swelling followed by drying, this same sequence actually increased gas transport. The eight- to ten-fold increase in Knudsen diffusion-based gas permeance after this pre-treatment was attributed to an increase in the number or size of membrane defects. © 2010 Elsevier B.V.

  20. Proteomics Analysis Reveals Distinct Corona Composition on Magnetic Nanoparticles with Different Surface Coatings: Implications for Interactions with Primary Human Macrophages.

    Directory of Open Access Journals (Sweden)

    Carmen Vogt

    Full Text Available Superparamagnetic iron oxide nanoparticles (SPIONs have emerged as promising contrast agents for magnetic resonance imaging. The influence of different surface coatings on the biocompatibility of SPIONs has been addressed, but the potential impact of the so-called corona of adsorbed proteins on the surface of SPIONs on their biological behavior is less well studied. Here, we determined the composition of the plasma protein corona on silica-coated versus dextran-coated SPIONs using mass spectrometry-based proteomics approaches. Notably, gene ontology (GO enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG pathway analysis revealed distinct protein corona compositions for the two different SPIONs. Relaxivity of silica-coated SPIONs was modulated by the presence of a protein corona. Moreover, the viability of primary human monocyte-derived macrophages was influenced by the protein corona on silica-coated, but not dextran-coated SPIONs, and the protein corona promoted cellular uptake of silica-coated SPIONs, but did not affect internalization of dextran-coated SPIONs.

  1. Osseoconductivity of a Specific Streptavidin-Biotin-Fibronectin Surface Coating of Biotinylated Titanium Implants - A Rabbit Animal Study.

    Science.gov (United States)

    Kämmerer, Peer W; Lehnert, Michael; Al-Nawas, Bilal; Kumar, Vinay V; Hagmann, Sebastien; Alshihri, Abdulmonem; Frerich, Bernhard; Veith, Michael

    2015-10-01

    Biofunctionalized implant surfaces may accelerate bony integration and increase long-term stability. The aim of the study was to evaluate the osseous reaction toward biomimetic titanium implants surfaces coated with quasicovalent immobilized fibronectin in an in vivo animal model. A total of 84 implants (uncoated [control 1, n = 36], streptavidin-biotin coated [test 1, n = 24], streptavidin-biotin-fibronectin coated [test 2, n = 24]) were inserted 1 mm supracortically in the proximal tibia of 12 rabbits. The samples were examined after 3 and 6 weeks. Total bone-implant contact (tBIC; %), bone-implant contact in the cortical (cBIC; %) and in the spongious bone (sBIC; %) as well as the percentage of linear bone fill (PLF; %) were evaluated. After 3 weeks, streptavidin-biotin-fibronectin implants had a significant higher sBIC (p = .043) and PLF (p = .007) compared with the uncoated samples. After 6 weeks, this difference was significant for tBIC (p = .016) and cBIC (p biotin-coated implants showed less bone growth at both time points of all examined parameters when compared with their counterparts (all p biotin-fibronectin system on smooth surface titanium shows a beneficial faster osseous healing in vivo. Besides, an antifouling effect of the streptavidin-biotin coating was proven. © 2015 Wiley Periodicals, Inc.

  2. Effects of particle size and surface coating on cellular uptake of polymeric nanoparticles for oral delivery of anticancer drugs.

    Science.gov (United States)

    Win, Khin Yin; Feng, Si-Shen

    2005-05-01

    This study evaluated cellular uptake of polymeric nanoparticles by using Caco-2 cells, a human colon adenocarcinoma cell line, as an in vitro model with the aim to apply nanoparticles of biodegradable polymers for oral chemotherapy. The feasibility was demonstrated by showing the localization and quantification of the cell uptake of fluorescent polystyrene nanoparticles of standard size and poly(lactic-co-glycolic acid) (PLGA) nanoparticles coated with polyvinyl alcohol (PVA) or vitamin E TPGS. Coumarin-6 loaded PLGA nanoparticles were prepared by a modified solvent extraction/evaporation method and characterized by laser light scattering for size and size distribution, scanning electron microscopy (SEM) for surface morphology, zeta-potential for surface charge, and spectrofluorometry for fluorescent molecule release from the nanoparticles. The effects of particle size and particle surface coating on the cellular uptake of the nanoparticles were quantified by spectrofluorometric measurement. Cellular uptake of vitamin E TPGS-coated PLGA nanoparticles showed 1.4 folds higher than that of PVA-coated PLGA nanoparticles and 4-6 folds higher than that of nude polystyrene nanoparticles. Images of confocal laser scanning microscopy, cryo-SEM and transmission electron microscopy clearly evidenced the internalization of nanoparticles by the Caco-2 cells, showing that surface modification of PLGA nanoparticles with vitamin E TPGS notably improved the cellular uptake. It is highly feasible for nanoparticles of biodegradable polymers to be applied to promote oral chemotherapy.

  3. Microstructural studies on friction surfaced coatings of Ni-based alloys; Gefuegeuntersuchungen an reibgeschweissten Beschichtungen von Ni-Basislegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Javed; Puli, Ramesh; Kalvala, Prasad Rao; Misra, Mano [Utah Univ., Salt Lake City, UT (United States). Dept. of Metallurgical Engineering

    2015-07-01

    Inconel 625, Inconel 600, Inconel 800H were friction surfaced on steel and Inconel substrates. The interface between steel and Ni-based alloys showed intermixing of two alloys while the interface between two Ni-based alloys showed no such intermixing. The XRD results confirmed that this intermixed zone consisted of mechanical mix two separate metals and no intermetallics were noticed. Friction surfaced Inconel coatings were metallurgically bonded to steel and Inconel substrates with out any physical defects such as voids or cracks. Friction surfaced coatings showed equiaxed fine grained microstructures (4-18 μm) compared with their consumable rod counterparts (12 - 85 μm). Scanning electron microscope electron backscattered diffraction results showed that the coatings consisted of mainly high angle grain boundaries indicative of dynamic recrystallization mechanism. The temperatures recorded using Infra Red camera showed that the temperature attained at the interface between rod and the substrate is about 1100 C. The grain size of the consumable rod was relatively fine near the coating/substrate interface and relatively coarser away from interface indicating the change in strain and temperature the rod experienced at or away from the interface.

  4. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    -laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single......The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre...

  5. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    of single mode fiber laser power. Burr free cuts in 1 mm steel and aluminum and in 1 and 2 mm AISI 304 stainless steel is demonstrated over a wide range of cutting rates. The industrial realization of this approach is foreseen to be performed by either beam patterning by diffractive optical elements......The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  6. X-ray photoelectron spectroscopy study of the metal/cermet interface

    International Nuclear Information System (INIS)

    Lu Hua; Shen Dianhong; Xue Qikun

    2001-01-01

    Interfacial reactions between aluminium and polycrystalline cermet TiC 0.6 were investigated using x-ray photo-electron spectroscopy, Auger electron spectroscopy and x-ray diffraction. It was found that titanium exists in two chemical states. The carbide and oxide of titanium can be detected simultaneously, and the atomic ratio of Ti:C:O is 5:3:2. This suggests that TiC 0.6 is a Ti-oxycarbide or oxygenated Tic composite: Ti 5 C 3 O 2 (TiO 2 + 4TiC 0.75 ). When Al is deposited in vacuum on the Ti-oxycarbide surface, the active Al atoms react chemically only with TiO 2 at room temperature, but not with TiC 0.75 in Ti-oxycarbide. The reaction products are Al 2 O 3 and the intermetallic compound Al 3 Ti. Annealing the Al/TiC 0.6 interface at 750 degree C, Al reacts also with TiC 0.75 to form a brittle Al 4 C 3 phase

  7. Re-activation of degraded nickel cermet anodes - Nano-particle formation via reverse current pulses

    Science.gov (United States)

    Hauch, A.; Marchese, M.; Lanzini, A.; Graves, C.

    2018-02-01

    The Ni/yttria-stabilized-zirconia (YSZ) cermet is the most commonly applied fuel electrode for solid oxide cells (SOCs). Loss of Ni/YSZ electrode activity is a key life-time limiting factor of the SOC. Developing means to mitigate this loss of performance or re-activate a fuel electrode is therefore important. In this work, we report a series of five tests on state-of-the-art Ni/YSZ-YSZ-CGObarrier-LSC/CGO cells. All cells were deliberately degraded via gas stream impurities in CO2/CO or harsh steam electrolysis operation. The cells were re-activated via a variety of reverse current treatments (RCTs). Via electrochemical impedance spectroscopy, we found that the Ni/YSZ electrode performance could be recovered via RCT, but not via constant fuel cell operation. For optimized RCT, we obtained a lower Ni/YSZ electrode resistance than the initial resistance. E.g. at 700 °C we measured fuel electrode resistance of 180 mΩ cm2, 390 mΩ cm2, and 159 mΩ cm2 before degradation, after degradation and after re-activation via RCT, respectively. Post-test SEM revealed that the RCT led to formation of nano-particles in the fuel electrode. Besides the remarkable improvement, the results also showed that RCTs can weaken Ni/YSZ interfaces and the electrode/electrolyte interface. This indicates that finding an optimum RCT profile is crucial for achieving maximum benefit.

  8. Corrosion of cermet anodes during low temperature electrolysis of alumina. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kozarek, R.L.; Ray, S.P.; Dawless, R.K.; LaCamera, A.F.

    1997-09-26

    Successful development of inert anodes to replace carbon anodes in Hall cells has the potential benefits of lower energy consumption,lower operating costs, and reduced CO{sub 2} and CO emissions. Using inert anodes at reduced current density and reduced operating temperature (800 C) has potential for decreasing the corrosion rate of inert anodes. It may also permit the use of new materials for containment and insulation. This report describes the fabrication characteristics and the corrosion performance of 5324-17% Cu Cermet anodes in 100 hour tests. Although some good results were achieved, the corrosion rate at low temperature (800 C) is varied and not significantly lower than typical results at high temperature ({approximately} 960 C). This report also describes several attempts at 200 hour tests, with one anode achieving 177 hours of continuous operation and another achieving a total of 235 hours but requiring three separate tests of the same anode. The longest run did show a lower wear rate in the last test; but a high resistance layer developed on the anode surface and forced an unacceptably low current density. It is recommended that intermediate temperatures be explored as a more optimal environment for inert anodes. Other electrolyte chemistries and anode compositions (especially high conductivity anodes) should be considered to alleviate problems associated with lower temperature operation.

  9. Fabrication and Testing of CERMET Fuel Materials for Nuclear Thermal Propulsion

    Science.gov (United States)

    Hickman, Robert; Broadway, Jeramie; Mireles, Omar

    2012-01-01

    A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on Nuclear Thermal Propulsion (NTP) is currently being developed for Advanced Space Exploration Systems. The overall goal of the project is to address critical NTP technology challenges and programmatic issues to establish confidence in the affordability and viability of NTP systems. The current technology roadmap for NTP identifies the development of a robust fuel form as a critical near term need. The lack of a qualified nuclear fuel is a significant technical risk that will require a considerable fraction of program resources to mitigate. Due to these risks and the cost for qualification, the development and selection of a primary fuel must begin prior to Authority to Proceed (ATP) for a specific mission. The fuel development is a progressive approach to incrementally reduce risk, converge the fuel materials, and mature the design and fabrication process of the fuel element. A key objective of the current project is to advance the maturity of CERMET fuels. The work includes fuel processing development and characterization, fuel specimen hot hydrogen screening, and prototypic fuel element testing. Early fuel materials development is critical to help validate requirements and fuel performance. The purpose of this paper is to provide an overview and status of the work at Marshall Space Flight Center (MSFC).

  10. Conceptual Design of a CERMET NTR Fission Core Using Multiphysics Modeling Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jonathan A. Webb; Brian J. Gross; William T. Taitano

    2011-08-01

    An initial pre-conceptual CERMET Nuclear Thermal Propulsion reactor system is investigated within this paper. Reactor configurations are investigated where the fuel consists of 60 vol.% UO2 and 40 vol.% W where the UO2 consists of Gd2O3 concentrations of 5 and 10 mol.%.Gd2O3. The fuel configuration consisting of 5 mol.% UO2 was found to have a total mass of 2761 kg and a thrust to weight ratio of 4.10 and required a coolant channel surface area to fueled volume ratio of approximately 15.0 in order to keep the centerline temperature below 3000 K. The configuration consisting of 10 mol.% Gd2O3 required a surface area to volume ratio of approximately 12.2 to cool the reactor to a peak temperature of 3000 K and had a total mass of 3200 kg and a thrust to weight ratio of 3.54. It is not known yet what concentration of Gd2O3 is required to maintain fuel stability at 3000 K; however, both reactors offer the potential for operations at 25,000 lb, and at a specific impulse which may range from 900 to 950 seconds.

  11. Corrosion of MTR type fuel plates containing U3O8-Al cermet cores

    International Nuclear Information System (INIS)

    Durazzo, M.

    1985-01-01

    The fuel plate samples containing U 3 O 8 -Al cermet cores with concentrations from 10 to 90% of U 3 O 8 weight were fabricated. Samples with 58% of U 3 O 8 eight were fabricated using compacts with densities from 75 to 95% of theoretical density. The influences of U 3 O 8 concentration and porosity of compacted core on porosity and uniformity of core thickness are discussed. The U 3 O 8 -Al cores were submitted to corrosion tests and exposed to deionized water at temperatures of 30, 50, 70 and 90 0 C by cladding deffect produced artificially. The results shown that core corrosion is accompanied by hydrogen release. The total volum of released hydrogen and the time interval to observe the initiation of hydrogen releasing (incubation time) are depending on core pososity and absolute temperature. A mechanism for U 3 O 8 -Al core corrosion process is proposed and discussed. The cladding of fuel plate samples was submitted to corrosion tests under similar conditons of the IAE-R1 reactor operating at 2, 5 and 10 MW. (Author) [pt

  12. Influence of Bond Coat on HVOF-Sprayed Gradient Cermet Coating on Copper Alloy

    Science.gov (United States)

    Ke, Peng; Cai, Fei; Chen, Wanglin; Wang, Shuoyu; Ni, Zhenhang; Hu, Xiaohong; Li, Mingxi; Zhu, Guanghong; Zhang, Shihong

    2017-06-01

    Coatings are required on mold copper plates to prolong their service life through enhanced hardness, wear resistance, and oxidation resistance. In the present study, NiCr-30 wt.%Cr3C2 ceramic-metallic (cermet) layers were deposited by high velocity oxy-fuel (HVOF) spraying on different designed bond layers, including electroplated Ni, HVOF-sprayed NiCr, and double-decker Ni-NiCr. Annealing was also conducted on the gradient coating (GC) with NiCr bond layer to improve the wear resistance and adhesion strength. Coating microstructure was investigated by scanning electron microscopy and x-ray diffraction analysis. Mechanical properties including microhardness, wear resistance, and adhesion strength of the different coatings were evaluated systematically. The results show that the types of metallic bond layer and annealing process had a significant impact on the mechanical properties of the GCs. The GCs with electroplated Ni bond layer exhibited the highest adhesion strength (about 70 MPa). However, the GC with HVOF-sprayed NiCr bond layer exhibited better wear resistance. The wear resistance and adhesion strength of the coating with NiCr metallic bond layer were enhanced after annealing.

  13. Effect of Surface Coating with Magnesium Stearate via Mechanical Dry Powder Coating Approach on the Aerosol Performance of Micronized Drug Powders from Dry Powder Inhalers

    OpenAIRE

    Zhou, Qi (Tony); Qu, Li; Gengenbach, Thomas; Larson, Ian; Stewart, Peter J.; Morton, David A. V.

    2012-01-01

    The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by las...

  14. Surfactant-free carnauba wax dispersion and its use for layer-by-layer assembled protective surface coatings on wood

    Science.gov (United States)

    Lozhechnikova, Alina; Bellanger, Hervé; Michen, Benjamin; Burgert, Ingo; Österberg, Monika

    2017-02-01

    Protection from liquid water and UV radiation are equally important, and a sophisticated approach is needed when developing surface coatings that preserve the natural and well-appreciated aesthetic appearance of wood. In order to prevent degradation and prolong the service life of timber, a protective coating was assembled using carnauba wax particles and zinc oxide nanoparticles via layer-by-layer deposition in water. For this purpose, a facile sonication route was developed to produce aqueous wax dispersion without any surfactants or stabilizers. The suspension was stable above pH 4 due to the electrostatic repulsion between the negatively charged wax particles. The particle size could be controlled by the initial wax concentration with average particle sizes ranging from 260 to 360 nm for 1 and 10 g/L, respectively. The deposition of wax particles onto the surface of spruce wood introduced additional roughness to the wood surface at micron level, while zinc oxide provided nano roughness and UV-absorbing properties. In addition to making wood superhydrophobic, this novel multilayer coating enhanced the natural moisture buffering capability of spruce. Moreover, wood surfaces prepared in this fashion showed a significant reduction in color change after exposure to UV light. A degradation of the wax through photocatalytic activity of the ZnO particles was measured by FTIR, indicating that further studies are required to achieve long-term stability. Nevertheless, the developed coating showed a unique combination of superhydrophobicity and excellent moisture buffering ability and some UV protection, all achieved using an environmentally friendly coating process, which is beneficial to retain the natural appearance of wood and improve indoor air quality and comfort.

  15. Surface coating changes the physiological and biochemical impacts of nano-TiO2 in basil (Ocimum basilicum) plants.

    Science.gov (United States)

    Tan, Wenjuan; Du, Wenchao; Barrios, Ana C; Armendariz, Raul; Zuverza-Mena, Nubia; Ji, Zhaoxia; Chang, Chong Hyun; Zink, Jeffrey I; Hernandez-Viezcas, Jose A; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L

    2017-03-01

    Little is known about the effects of surface coating on the interaction of engineered nanoparticles (ENPs) with plants. In this study, basil (Ocimum basilicum) was cultivated for 65 days in soil amended with unmodified, hydrophobic (coated with aluminum oxide and dimethicone), and hydrophilic (coated with aluminum oxide and glycerol) titanium dioxide nanoparticles (nano-TiO 2 ) at 125, 250, 500, and 750 mg nano-TiO 2 kg -1 soil. ICP-OES/MS, SPAD meter, and UV/Vis spectrometry were used to determine Ti and essential elements in tissues, relative chlorophyll content, carbohydrates, and antioxidant response, respectively. Compared with control, hydrophobic and hydrophilic nano-TiO 2 significantly reduced seed germination by 41% and 59%, respectively, while unmodified and hydrophobic nano-TiO 2 significantly decreased shoot biomass by 31% and 37%, respectively (p ≤ 0.05). Roots exposed to hydrophobic particles at 750 mg kg -1 had 87% and 40% more Ti than the pristine and hydrophilic nano-TiO 2 ; however, no differences were found in shoots. The three types of particles affected the homeostasis of essential elements: at 500 mg kg - 1 , unmodified particles increased Cu (104%) and Fe (90%); hydrophilic increased Fe (90%); while hydrophobic increased Mn (339%) but reduced Ca (71%), Cu (58%), and P (40%). However, only hydrophobic particles significantly reduced root elongation by 53%. Unmodified, hydrophobic, and hydrophilic particles significantly reduced total sugar by 39%, 38%, and 66%, respectively, compared with control. Moreover, unmodified particles significantly decreased reducing sugar (34%), while hydrophobic particles significantly reduced starch (35%). Although the three particles affected basil plants, coated particles impacted the most its nutritional quality, since they altered more essential elements, starch, and reducing sugars. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Impact of surface coating and particle size on the uptake of small and ultrasmall superparamagnetic iron oxide nanoparticles by macrophages.

    Science.gov (United States)

    Saito, Shigeyoshi; Tsugeno, Mana; Koto, Daichi; Mori, Yuki; Yoshioka, Yoshichika; Nohara, Satoshi; Murase, Kenya

    2012-01-01

    Magnetic resonance imaging (MRI) using contrast agents like superparamagnetic iron oxide (SPIO) is an extremely versatile technique to diagnose diseases and to monitor treatment. This study tested the relative importance of particle size and surface coating for the optimization of MRI contrast and labeling efficiency of macrophages migrating to remote inflammation sites. We tested four SPIO and ultrasmall superparamagnetic iron oxide (USPIO), alkali-treated dextran magnetite (ATDM) with particle sizes of 28 and 74 nm, and carboxymethyl dextran magnetite (CMDM) with particle sizes of 28 and 72 nm. Mouse macrophage RAW264 cells were incubated with SPIOs and USPIOs, and the labeling efficiency of the cells was determined by the percentage of Berlin blue-stained cells and by measuring T(2) relaxation times with 11.7-T MRI. We used trypan blue staining to measure cell viability. Analysis of the properties of the nanoparticles revealed that ATDM-coated 74 nm particles have a lower T(2) relaxation time than the others, translating into a higher ability of MRI negative contrast agent. Among the other three candidates, CMDM-coated particles showed the highest T(2) relaxation time once internalized by macrophages. Regarding labeling efficiency, ATDM coating resulted in a cellular uptake higher than CMDM coating, independent of nanoparticle size. None of these particle formulations affected macrophage viability. This study suggests that coating is more critical than size to optimize the SPIO labeling of macrophages. Among the formulations tested in this study, the best MRI contrast and labeling efficiency are expected with ATDM-coated 74 nm nanoparticles.

  17. Effects on cytotoxicity and antibacterial properties of the incorporations of silver nanoparticles into the surface coating of dental alloys.

    Science.gov (United States)

    Shen, Xiao-Ting; Zhang, Yan-Zhen; Xiao, Fang; Zhu, Jing; Zheng, Xiao-Dong

    2017-07-01

    The aim of this study was to research the changes in cytotoxicity and antibacterial properties after silver nanoparticles (AgNPs) were incorporated into the surface coating of dental alloys. AgNPs were attached to cobalt chromium alloys and pure titanium using a hydrothermal method, according to the reaction: AgNO 3 +NaBH 4 → Ag+1/2H 2 +1/2B 2 H 6 +NaNO 3 . A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of the alloys when in contact with osteogenic precursor cells (MC3T3-E1) from mice and mesenchymal stem cells (BMSC) from rats. The antibacterial properties of dental alloys incorporating three different concentrations (10, 4, and 2 μmol/L) of AgNPs were tested on Staphylococcus aureus (SA) and Streptococcus mutans (MS). High cytotoxicity values were observed for all dental alloys that contained 0% of AgNPs (the control groups). The incorporation of AgNPs reduced cytotoxicity values. No significant difference was observed for antibacterial performance when comparing dental alloys containing AgNPs to the respective control groups. The results demonstrated that the cobalt chromium alloys and pure titanium all had cytotoxicity to MC3T3-E1 and BMSC and that the incorporation of AgNPs could reduce this cytotoxicity. The concentrations of AgNPs adopted in this study were found to have no antibacterial action against SA or MS.

  18. Soudage par explosion thermique sous charge de cermets poreux à base de TiC-Ni sur substrat en acier-comportement tribologique Welding of porous TiC–Ni based cermets on substrate steel by thermal explosion under load-tribological behaviour

    Directory of Open Access Journals (Sweden)

    Lemboub Samia

    2013-11-01

    Full Text Available Dans ce travail, nous nous intéressons à l'élaboration de cermets à base de TiC-Ni par dispersion de particules de carbures, oxydes ou borures dans une matrice de nickel, grâce à la technique de l'explosion thermique sous une charge de 20 MPa. La combustion de mélanges actifs (Ti-C-Ni-An où An = Al2O3, MgO, SiC, TiB2, WC, basée sur la réaction de synthèse de TiC (ΔHf298K = −184 kJ/mole, génère des cermets complexes. Un court maintien sous charge du cermet à 1373 K, après l'explosion thermique, permet son soudage sur un substrat en acier XC55. Les cermets obtenus dans ces conditions demeurent poreux et conservent une porosité de l'ordre de 25–35 %. La densité relative du cermet, sa dureté et son comportement tribologique, dépendront de la nature de l'addition dans les mélanges de départ. Porous TiC-Ni based cermets were obtained by dispersion of carbides, oxides or borides particles in a nickel matrix thanks to the thermal explosion technique realized under a load of 20 MPa. The combustion of active mixtures (Ti-C-Ni-An where An = Al2O3, MgO, SiC, TiB2 or WC based on the titanium carbide reaction synthesis (ΔHf = −184 kJ/mol, generates porous complex cermets. After the thermal explosion, a short maintenance under load at 1373 K of the combustion product, allows at the same time the cermets welding on a carbon steel substrate. The obtained cermets under these conditions preserve a porosity of about 25–35%. The relative density, hardness and tribological behaviour of the complex cermets depend on the additions nature (An in the starting mixtures.

  19. Welding and cutting

    International Nuclear Information System (INIS)

    Drews, P.; Schulze Frielinghaus, W.

    1978-01-01

    This is a survey, with 198 literature references, of the papers published in the fields of welding and cutting within the last three years. The subjects dealt with are: weldability of the materials - Welding methods - Thermal cutting - Shaping and calculation of welded joints - Environmental protection in welding and cutting. (orig.) [de

  20. High temperature oxidation behaviour of nanostructured cermet coatings in amixed CO/sub 2/ - O/sub 2/ environment

    International Nuclear Information System (INIS)

    Farrokhzad, M. A.; Khan, T. I.

    2013-01-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (alpha-Al /sub 2/O/sub 3/ and TiO/sub 2/) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500 degree C, 600 degree C and 700 degree C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15 percentage CO/sub 2/, 10 percentage O/sub 2/ and 75 percentage N/sub 2/. This research investigates the effects of CO/sub 2/ and O/sub 2/ partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO/sub 2/ at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO/sub 2/ in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO/sub 2/ acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO/sub 2/ particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Nu i-Tau i compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings. (author)

  1. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 – O2 environment

    International Nuclear Information System (INIS)

    Farrokhzad, M A; Khan, T I

    2014-01-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al 2 O3 and TiO 2 ) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO 2 , 10% O 2 and 75% N 2 . This research investigates the effects of CO 2 and O 2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO 2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO 2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO 2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings

  2. Impact of Reduction Parameters on the Initial Performance and Stability of Ni/(Sc)YSZ Cermet Anodes for SOFCs

    DEFF Research Database (Denmark)

    Ebbehøj, Søren Lyng; Ramos, Tania; Mogensen, Mogens Bjerg

    2012-01-01

    processes for Ni/10Sc1YSZ cells. The Ni/8YSZ cells behaved oppositely with respect to reduction temperature. A hypothesis is proposed relating performance to variations in Ni microstructure, Ni/ceramic contacting and extent of TPB resulting from differences in reduction parameters. Further, the performance......In-situ reduction of Ni cermet anodes produces the porosity and influences the microstructure, performance and stability of the anodes. The impact on initial performance, stability and microstructure of two different reduction procedures currently in use at DTU Energy Conversion with reduction...... stability under high steam conditions was evaluated, and very stable performances and microstructures of the anode layers were observed....

  3. Electrical properties and conduction mechanisms of Ru-based thick-film (cermet) resistors

    International Nuclear Information System (INIS)

    Pike, G.E.; Seager, C.H.

    1977-01-01

    This paper presents an experimental study of the electrical conduction mechanisms in thick-film (cermet) resistor. The resistors were made from one custom and three commercially formulated inks with sheet resistivities ranging from 10 2 to 10 6 Ω/D 7 Alembertian in decade increments. Their microstructure and composition have been examined using optical and scanning electron microscopy, electron microprobe analysis, x-ray diffraction, and various chemical analyses. This portion of our study shows that the resistors are heterogeneous mixtures of metallic metal oxide particles (approx.4 x 10 -5 cm in diameter) and a lead silicate glass. The metal oxide particles are ruthenium containing pyrochlores, and are joined to form a continuous three-dimensional network of chain segments. The principal experimental work reported here is an extensive study of the electrical transport properties of the resistors. The temperature dependence of conductance has been measured from 1.2 to 400 K, and two features common to all resistors are found. There is a pronounced decrease in conductance at low temperatures and a shallow maximum at several hundred Kelvin. Within the same range of temperatures the reversible conductance as a function of electric field from 0 to 28 kV/cm has been studied. The resistors are non-Ohmic at all temperatures, but particularly at cryogenic temperatures for low fields. At higher fields the conductance shows a linear variation with electric field. The thick-film resistors are found to have a small dielectric constant and a (nearly) frequency-independent conductance from dc to 50 MHz. The magnetoresistance to 100 kG, the Hall mobility, and the Seebeck coefficient of most of the resistors have been measured and discovered to be quite small. Many of the electrical transport properties have also been determined for the metal oxide particles which were extracted from the fired resistors

  4. Characterization and High-Temperature Erosion Behaviour of HVOF Thermal Spray Cermet Coatings

    Science.gov (United States)

    Kumar, Pardeep; Sidhu, Buta Singh

    2016-01-01

    High-velocity oxygen fuel (HVOF) thermal spray, carbide-cermet-based coatings are usually employed in high-temperature erosive and erosive-corrosive environments. Extensive literature is available on high-temperature erosion performance of HVOF coatings under moderate to low particle flux and velocities for application in boiler tubes. This research work presents the characterization and high-temperature erosion behaviour of Cr3C2-25NiCr and WC-10Co-4Cr HVOF-sprayed coatings. Coatings were formulated on the substrate steel of type AISI 304, commonly used for the fabrication of pulverized coal burner nozzles (PCBN). Erosion testing was carried out in high-temperature air-jet erosion tester after simulating the conditions akin to that prevailing in PCBN in the boiler furnace. The coatings were tested for erosion behaviour at different angles and temperatures by freezing other test parameters. Brittle erosion behaviour was depicted in erosion testing, and the coatings couldn't restrain the erodent attacks to protect the substrate. High particle velocity and high particle flux were attributed to be the reasons of extensive erosive weight loss of the coatings. The surface morphology of the eroded specimens was analysed from back-scattered electron images to depict the probable mechanism of material removal. The coatings were characterized with optical microscopy, SEM-EDS analysis, XRD analysis, micro-hardness testing, porosity measurements, surface roughness testing and bond strength testing. The work was undertaken to investigate the performance of the selected coatings in highly erosive environment, so as to envisage their application in PCBNs for protection against material degradation. The coatings could only sustain in oblique impact erosion at room temperature and depleted fully under all other conditions.

  5. Small PWR 'PFPWR50' using cermet fuel of Th-Pu particles

    International Nuclear Information System (INIS)

    Hirayama, Takashi; Shimazu, Yoichiro

    2009-01-01

    An innovative concept of PFPWR50 has been studied. The main feature of PFPWR50 has been to adopt TRISO coated fuel particles in a conventional PWR cladding. Coated fuel particle provides good confining ability of fission products. But it is pointed out that swelling of SiC layer at low temperature by irradiation has possibilities of degrading the integrity of coated fuel particle in the LWR environment. Thus, we examined the use of Cermet fuel replacing SiC layer to Zr metal or Zr compound. And the nuclear fuel has been used as fuel compact, which is configured to fix coated fuel particles in the matrix material to the shape of fuel pellet. In the previous study, graphite matrix is adopted as the matrix material. According to the burnup calculations of the several fuel concepts with those covering layers, we decide to use Zr layer embedded in Zr metal base or ZrC layer with graphite matrix. But carbon has the problem at low temperature by irradiation as well as SiC. Therefore, Zr covering layer and Zr metal base are finally selected. The other feature of PFPWR50 concept has been that the excess reactivity is suppressed during a cycle by initially loading burnable poison (gadolinia) in the fuels. In this study, a new loading pattern is determined by combining 7 types of assemblies in which the gadolinia concentration and the number of the fuel rods with gadolinia are different. This new core gives 6.7 equivalent full power years (EFPY) as the core life of a cycle. And the excess reactivity is suppressed to less than 2.0%Δk/k during the cycle. (author)

  6. Device for cutting protrusions

    Science.gov (United States)

    Bzorgi, Fariborz M [Knoxville, TN

    2011-07-05

    An apparatus for clipping a protrusion of material is provided. The protrusion may, for example, be a bolt head, a nut, a rivet, a weld bead, or a temporary assembly alignment tab protruding from a substrate surface of assembled components. The apparatus typically includes a cleaver having a cleaving edge and a cutting blade having a cutting edge. Generally, a mounting structure configured to confine the cleaver and the cutting blade and permit a range of relative movement between the cleaving edge and the cutting edge is provided. Also typically included is a power device coupled to the cutting blade. The power device is configured to move the cutting edge toward the cleaving edge. In some embodiments the power device is activated by a momentary switch. A retraction device is also generally provided, where the retraction device is configured to move the cutting edge away from the cleaving edge.

  7. Food contact surfaces coated with nitrogen-doped titanium dioxide: effect on Listeria monocytogenes survival under different light sources

    International Nuclear Information System (INIS)

    Rodrigues, D.; Teixeira, P.; Tavares, C.J.; Azeredo, J.

    2013-01-01

    Improvement of food safety is a very important issue, and is on the basis of production and application of new/modified food contact surfaces. Titanium dioxide (TiO 2 ) and, more recently, nitrogen-doped titanium dioxide (N-TiO 2 ) coatings are among the possible forms to enhance food contact surfaces performance in terms of higher hygiene and easier sanitation. In this context, the present work aimed at evaluating the bactericidal activity of an N-TiO 2 coating on glass and stainless steel under two different sources of visible light – fluorescent and incandescent – and ultraviolet (UV) irradiation. Listeria monocytogenes was chosen as representative of major foodborne pathogens and its survival was tested on N-TiO 2 coated coupons. In terms of survival percentage, good results were obtained after exposure of coated surfaces to all light types since, apart from the value obtained after exposing glass to fluorescent light (56.3%), survival rates were always below 50%. However, no effective disinfection was obtained, given that for a disinfectant or sanitizing agent to be claimed as effective it needs to be able to promote at least a 3-log reduction of the microbial load, which was not observed for any of the experimental conditions assessed. Even so, UV irradiation was the most successful on eliminating cells on coated surfaces, since the amount of bacteria was reduced to 1.49 × 10 6 CFU/ml on glass and 2.37 × 10 7 on stainless steel. In contrast, both visible light sources had only slightly decreased the amount of viable cells, which remained in the range of 8 log CFU/ml. Hence, although some bactericidal effect was accomplished under visible light, UV was the most effective light source on promoting photocatalytic reactions on N-TiO 2 coated coupons and none of the experimental conditions have reached a satisfactory disinfection level. Thus, this surface coating needs further research and improvement in order to become truly effective against foodborne

  8. Surfactant-free carnauba wax dispersion and its use for layer-by-layer assembled protective surface coatings on wood

    Energy Technology Data Exchange (ETDEWEB)

    Lozhechnikova, Alina [Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, FI-00076, Aalto (Finland); Bellanger, Hervé; Michen, Benjamin; Burgert, Ingo [Institute for Building Materials (IfB), Wood Materials Science, ETH Zürich, Stefano-Franscini-Platz 3, 8093 Zürich (Switzerland); Applied Wood Materials Laboratory, Empa − Swiss Federal Laboratories for Material Testing and Research, 8600 Dübendorf (Switzerland); Österberg, Monika, E-mail: monika.osterberg@aalto.fi [Department of Forest Products Technology, School of Chemical Technology, Aalto University, P.O. Box 16300, FI-00076, Aalto (Finland)

    2017-02-28

    Highlights: • A facile sonication route to produce aqueous wax dispersions is developed. • The wax dispersion is naturally stable and free of surfactants or stabilizers. • Wax and ZnO particles are coated onto wood using layer-by-layer assembly. • The coating brings superhydrophobicity while preserving moisture buffering. • ZnO improves the color stability of wood to UV light. - Abstract: Protection from liquid water and UV radiation are equally important, and a sophisticated approach is needed when developing surface coatings that preserve the natural and well-appreciated aesthetic appearance of wood. In order to prevent degradation and prolong the service life of timber, a protective coating was assembled using carnauba wax particles and zinc oxide nanoparticles via layer-by-layer deposition in water. For this purpose, a facile sonication route was developed to produce aqueous wax dispersion without any surfactants or stabilizers. The suspension was stable above pH 4 due to the electrostatic repulsion between the negatively charged wax particles. The particle size could be controlled by the initial wax concentration with average particle sizes ranging from 260 to 360 nm for 1 and 10 g/L, respectively. The deposition of wax particles onto the surface of spruce wood introduced additional roughness to the wood surface at micron level, while zinc oxide provided nano roughness and UV-absorbing properties. In addition to making wood superhydrophobic, this novel multilayer coating enhanced the natural moisture buffering capability of spruce. Moreover, wood surfaces prepared in this fashion showed a significant reduction in color change after exposure to UV light. A degradation of the wax through photocatalytic activity of the ZnO particles was measured by FTIR, indicating that further studies are required to achieve long-term stability. Nevertheless, the developed coating showed a unique combination of superhydrophobicity and excellent moisture buffering

  9. Food contact surfaces coated with nitrogen-doped titanium dioxide: effect on Listeria monocytogenes survival under different light sources

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, D.; Teixeira, P. [Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Tavares, C.J. [Center of Physics, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); Azeredo, J., E-mail: jazeredo@deb.uminho.pt [Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2013-04-01

    Improvement of food safety is a very important issue, and is on the basis of production and application of new/modified food contact surfaces. Titanium dioxide (TiO{sub 2}) and, more recently, nitrogen-doped titanium dioxide (N-TiO{sub 2}) coatings are among the possible forms to enhance food contact surfaces performance in terms of higher hygiene and easier sanitation. In this context, the present work aimed at evaluating the bactericidal activity of an N-TiO{sub 2} coating on glass and stainless steel under two different sources of visible light – fluorescent and incandescent – and ultraviolet (UV) irradiation. Listeria monocytogenes was chosen as representative of major foodborne pathogens and its survival was tested on N-TiO{sub 2} coated coupons. In terms of survival percentage, good results were obtained after exposure of coated surfaces to all light types since, apart from the value obtained after exposing glass to fluorescent light (56.3%), survival rates were always below 50%. However, no effective disinfection was obtained, given that for a disinfectant or sanitizing agent to be claimed as effective it needs to be able to promote at least a 3-log reduction of the microbial load, which was not observed for any of the experimental conditions assessed. Even so, UV irradiation was the most successful on eliminating cells on coated surfaces, since the amount of bacteria was reduced to 1.49 × 10{sup 6} CFU/ml on glass and 2.37 × 10{sup 7} on stainless steel. In contrast, both visible light sources had only slightly decreased the amount of viable cells, which remained in the range of 8 log CFU/ml. Hence, although some bactericidal effect was accomplished under visible light, UV was the most effective light source on promoting photocatalytic reactions on N-TiO{sub 2} coated coupons and none of the experimental conditions have reached a satisfactory disinfection level. Thus, this surface coating needs further research and improvement in order to become truly

  10. Electrochemical reduction of CerMet fuels for transmutation using surrogate CeO2-Mo pellets

    Science.gov (United States)

    Claux, B.; Souček, P.; Malmbeck, R.; Rodrigues, A.; Glatz, J.-P.

    2017-08-01

    One of the concepts chosen for the transmutation of minor actinides in Accelerator Driven Systems or fast reactors proposes the use of fuels and targets containing minor actinides oxides embedded in an inert matrix either composed of molybdenum metal (CerMet fuel) or of ceramic magnesium oxide (CerCer fuel). Since the sufficient transmutation cannot be achieved in a single step, it requires multi-recycling of the fuel including recovery of the not transmuted minor actinides. In the present work, a pyrochemical process for treatment of Mo metal inert matrix based CerMet fuels is studied, particularly the electroreduction in molten chloride salt as a head-end step required prior the main separation process. At the initial stage, different inactive pellets simulating the fuel containing CeO2 as minor actinide surrogates were examined. The main studied parameters of the process efficiency were the porosity and composition of the pellets and the process parameters as current density and passed charge. The results indicated the feasibility of the process, gave insight into its limiting parameters and defined the parameters for the future experiment on minor actinide containing material.

  11. Phase and crystallite size analysis of (Ti1-xMox)C-(Ni,Cr) cermet obtained by mechanical alloying

    Science.gov (United States)

    Suryana, Anis, Muhammad; Manaf, Azwar

    2018-04-01

    In this paper, we report the phase and crystallite size analysis of (Ti1-xMox)C-(Ni,Cr) with x = 0-0.5 cermet obtained by mechanical alloying of Ti, Mo, Ni, Cr and C elemental powders using a high-energy shaker ball mill under wet condition for 10 hours. The process used toluene as process control agent and the ball to mass ratio was 10:1. The mechanically milled powder was then consolidated and subsequently heated at a temperature 850°C for 2 hours under an argon flow to prevent oxidation. The product was characterized by X-ray diffraction (XRD) and scanning electron microscope equipped with energy dispersive analyzer. Results shown that, by the selection of appropriate condition during the mechanical alloying process, a metastable Ti-Ni-Cr-C powders could be obtained. The powder then allowed the in situ synthesis of TiC-(Ni,Cr) cermet which took place during exposure time at a high temperature that applied in reactive sintering step. Addition to molybdenum has caused shifting the TiC XRD peaks to a slightly higher angle which indicated that molybdenum dissolved in TiC phase. The crystallite size distribution of TiC is discussed in the report, which showing that the mean size decreased with the addition of molybdenum.

  12. Preparation of Ni-YSZ Cermet through Reduction of NiO-YSZ Ceramic for SOFC Anode

    Science.gov (United States)

    Baity, P. S. N.; Budiana, B.; Suasmoro, S.

    2017-07-01

    Research on the synthesis of Nickel-Yttria Stabilized Zirconia (Ni-YSZ) cermet for Solid Oxide Fuel Cell (SOFC) anode has been performed. The preparation was carried out through the reduction process of the Nickel Oxide-Yttria stabilized Zirconia (NiO-YSZ) ceramic. NiO and YSZ were prepared separately, the NiO powder was prepared by calcination of CH4Ni3O7.xH2O at 500°C for 3 hours, while YSZ powder was prepared by calcination of 7mol% Y2O3 and 93mol% ZrO2 mixture at 1350°C for an hour. The NiO-YSZ ceramic preparation was carried outby mixing of YSZ and NiO powder with natural white starch by weight ratio NiO: YSZ: natural white starch = 4:6:1 followed by sintering at 1200°C for 4 hours. The completion of reduction process of NiO-YSZ ceramic was performed at 1000°C in flowing Argon (Ar) containing 10% Hydrogen (H2) up to 4 hours. The characterisations include thermogravimetric analysis (TGA), XRD, SEM-EDX and Impedance Analyzer meter. The synthesised Ni-YSZ cermet at composition 33wt% Ni and 67wt% YSZ, shows relative density 70% and electrical conductivity 10-2 S/cm at 700°C, it qualifies as anode for SOFC.

  13. The effects of microstructure on the corrosion of glycine/nitrate processed cermet inert anodes: A preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Jr, C F; Chick, L A; Maupin, G D; Stice, N D

    1991-07-01

    The Inert Electrodes Program at the Pacific Northwest Laboratory (PNL) is supported by the Office of Industrial Processes of the US Department of Energy and is aimed at improving the energy efficiency of Hall-Heroult cells through the development of inert anodes. The inert anodes currently under the study are composed of a cermet material of the general composition NiO-NiFe{sub 2}O{sub 4}-Cu. The program has three primary objectives: (a) to evaluate the anode material in a scaled-up, pilot cell facility, (b) to investigate the mechanisms of the electrochemical reactions at the anodes surface, and (c) to develop sensors for monitoring various anode and/or electrolyte conditions. This report covers the results of a portion of the studies on anode reaction mechanisms. The anode mechanism studies were focused in four areas in FY 1990 and FY 1991: (a) the determination of whether a film formed on cermet inert anodes and (if it existed) the characterization of this film, (b) the determination of the sources of the anode impedance, (c) the evaluation of the effects of silica and a precorroded state on anode corrosion, and (d) a preliminary study on the effect of microstructure on the corrosion properties of the anodes. This report discusses the results of the microstructure studies. 6 refs., 32 figs., 3 tabs.

  14. Development of UO2/PuO2 dispersed in uranium matrix CERMET fuel system for fast reactors

    International Nuclear Information System (INIS)

    Sinha, V.P.; Hegde, P.V.; Prasad, G.J.; Pal, S.; Mishra, G.P.

    2012-01-01

    CERMET fuel with either PuO 2 or enriched UO 2 dispersed in uranium metal matrix has a strong potential of becoming a fuel for the liquid metal cooled fast breeder reactors (LMR’s). In fact it may act as a bridge between the advantages and disadvantages associated with the two extremes of fuel systems (i.e. ceramic fuel and metallic fuel) for fast reactors. At Bhabha Atomic Research Centre (BARC), R and D efforts are on to develop this CERMET fuel by powder metallurgy route. This paper describes the development of flow sheet for preparation of UO 2 dispersed in uranium metal matrix pellets for three different compositions i.e. U–20 wt%UO 2 , U–25 wt%UO 2 and U–30 wt%UO 2 . It was found that the sintered pellets were having excellent integrity and their linear mass was higher than that of carbide fuel pellets used in Fast Breeder Test Reactor programme (FBTR) in India. The pellets were characterized by X-ray diffraction (XRD) technique for phase analysis and lattice parameter determination. The optical microstructures were developed and reported for all the three different U–UO 2 compositions.

  15. Chronic TiO{sub 2} nanoparticle exposure to a benthic organism, Hyalella azteca: impact of solar UV radiation and material surface coatings on toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Wallis, Lindsay K. [Office of Research and Development, Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Duluth, MN, 55804 (United States); Diamond, Stephen A. [Nanosafe Inc., Blacksburg, VA, 24060 (United States); Ma, Hongbo [University of Wisconsin-Milwaukee, Zilber School of Public Health, Milwaukee, WI, 53211 (United States); Hoff, Dale J. [Office of Research and Development, Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Duluth, MN, 55804 (United States); Al-Abed, Souhail R. [National Risk Management Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, OH 45268 (United States); Li, Shibin, E-mail: lishibinepa@gmail.com [Office of Research and Development, Mid-Continent Ecology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Duluth, MN, 55804 (United States)

    2014-11-15

    There is limited information on the chronic effects of nanomaterials to benthic organisms, as well as environmental mitigating factors that might influence this toxicity. The present study aimed to fill these data gaps by examining various growth endpoints (weight gain, instantaneous growth rate, and total protein content) for up to a 21 d sediment exposure of TiO{sub 2} nanoparticles (nano-TiO{sub 2}) to a representative benthic species, Hyalella azteca. An uncoated standard, P25, and an Al(OH){sub 3} coated nano-TiO{sub 2} used in commercial products were added to sediment at 20 mg/L or 100 mg/L Under test conditions, UV exposure alone was shown to be a greater cause of toxicity than even these high levels of nano-TiO{sub 2} exposure, indicating that different hazards need to be addressed in toxicity testing scenarios. In addition, this study showed the effectiveness of a surface coating on the decreased photoactivity of the material, as the addition of an Al(OH){sub 3} coating showed a dramatic decrease in reactive oxygen species (ROS) production. However, this reduced photoactivity was found to be partially restored when the coating had been degraded, leading to the need for future toxicity tests which examine the implications of weathering events on particle surface coatings. - Highlights: • Chronic toxicity of nano-TiO{sub 2} to a benthic organism (Hyalella azteca) was examined. • Phototoxicity was investigated through exposure of solar simulated radiation (SSR). • The degradation of a surface coating resulted in an increase in photoactivity. • In this testing scenario, UV had a larger impact than chemical exposure in toxicity.

  16. Ultrasonic Cutting of Foods

    Science.gov (United States)

    Schneider, Yvonne; Zahn, Susann; Rohm, Harald

    In the field of food engineering, cutting is usually classified as a mechanical unit operation dealing with size reduction by applying external forces on a bulk product. Ultrasonic cutting is realized by superpositioning the macroscopic feed motion of the cutting device or of the product with a microscopic vibration of the cutting tool. The excited tool interacts with the product and generates a number of effects. Primary energy concentration in the separation zone and the modification of contact friction along the tool flanks arise from the cyclic loading and are responsible for benefits such as reduced cutting force, smooth cut surface, and reduced product deformation. Secondary effects such as absorption and cavitation originate from the propagation of the sound field in the product and are closely related to chemical and physical properties of the material to be cut. This chapter analyzes interactions between food products and ultrasonic cutting tools and relates these interactions with physical and chemical product properties as well as with processing parameters like cutting velocity, ultrasonic amplitude and frequency, and tool design.

  17. Underwater cutting techniques developments

    International Nuclear Information System (INIS)

    Bach, F.-W.

    1990-01-01

    The primary circuit structures of different nuclear powerplants are constructed out of stainless steels, ferritic steels, plated ferritic steels and alloys of aluminium. According to the level of the specific radiation of these structures, it is necessary for dismantling to work with remote controlled cutting techniques. The most successful way to protect the working crew against exposure of radiation is to operate underwater in different depths. The following thermal cutting processes are more or less developed to work under water: For ferritic steels only - flame cutting; For ferritic steels, stainless steels, cladded steels and aluminium alloys - oxy-arc-cutting, arc-waterjet-cutting with a consumable electrode, arc-saw-cutting, plasma-arc-cutting and plasma-arc-saw. The flame cutting is a burning process, all the other processes are melt-cutting processes. This paper explains the different techniques, giving a short introduction of the theory, a discussion of the possibilities with the advantages and disadvantages of these processes giving a view into the further research work in this interesting field. (author)

  18. The structurally effect of surface coated rhamnogalacturonan I on response of the osteoblast-like cell line SaOS-2

    DEFF Research Database (Denmark)

    Svava, Rikke; Gurzawska, Katarzyna; Yihau, Yu

    2014-01-01

    Osseointegration is important when implants are inserted into the bone and can be improved by biochemical surface coating of the implant. In this paper enzymatically modified rhamnogalacturonan I (RG-I) from apple and lupin was used for biochemical coating of aminated surfaces and the importance...... of the quality of RG-I, the nature of the binding, the fine structure of RG-I, and its effect on SaOS-2 cell line cultured on coated surfaces was investigated. SaOS-2 cells are osteoblast-like cells and a well-established in vitro model of bone-matrix forming osteoblasts. Purification by gel filtration could...

  19. Surface coating of siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers: Enhanced gene silencing and reduced adversed effects in vitro

    DEFF Research Database (Denmark)

    Zeng, Xianghui; de Groot, A. M.; Sijts, Alice

    2015-01-01

    giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did...... not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA–peptidomimetic nanocomplex core...

  20. Cutting Class Harms Grades

    Science.gov (United States)

    Taylor, Lewis A., III

    2012-01-01

    An accessible business school population of undergraduate students was investigated in three independent, but related studies to determine effects on grades due to cutting class and failing to take advantage of optional reviews and study quizzes. It was hypothesized that cutting classes harms exam scores, attending preexam reviews helps exam…

  1. Fundamentals of cutting.

    Science.gov (United States)

    Williams, J G; Patel, Y

    2016-06-06

    The process of cutting is analysed in fracture mechanics terms with a view to quantifying the various parameters involved. The model used is that of orthogonal cutting with a wedge removing a layer of material or chip. The behaviour of the chip is governed by its thickness and for large radii of curvature the chip is elastic and smooth cutting occurs. For smaller thicknesses, there is a transition, first to plastic bending and then to plastic shear for small thicknesses and smooth chips are formed. The governing parameters are tool geometry, which is principally the wedge angle, and the material properties of elastic modulus, yield stress and fracture toughness. Friction can also be important. It is demonstrated that the cutting process may be quantified via these parameters, which could be useful in the study of cutting in biology.

  2. Exploring Cu2O/Cu cermet as a partially inert anode to produce aluminum in a sustainable way

    International Nuclear Information System (INIS)

    Feng, Li-Chao; Xie, Ning; Shao, Wen-Zhu; Zhen, Liang; Ivanov, V.V.

    2014-01-01

    Highlights: • Cu 2 O/Cu cermet was used as a candidate partially inert anode material to produce aluminum alloys. • The thermal corrosion behavior of Cu 2 O/Cu was investigated in molten salt at 960 °C. • The corrosion rate is largely governed by the geometrical structures of Cu in the prepared samples. • The corrosion rate increases with decreasing sizes and increasing filling contents of Cu phase. • The corrosion rate was 1.8–9 cm/y and the Cu contents is less than 6.2 wt.% in the produced aluminum. - Abstract: As an energy-intensive process, aluminum production by the Hall–Héroult method accounts for significant emissions of CO 2 and some toxic greenhouse gases. The utilization of an inert anode in place of a carbon anode was considered as a revolutionary technique to solve most of the current environmental problems resulting from the Hall–Héroult process. However, the critical property requirements of the inert anode materials significantly limit the application of this technology. In light of the higher demand for aluminum alloys than for pure aluminum, a partially inert anode was designed to produce aluminum alloys in a more sustainable way. Here, Cu 2 O/Cu cermet was chosen as the material of interest. The thermal corrosion behavior of Cu 2 O/Cu was investigated in Na 3 AlF 6 –CaF 2 –Al 2 O 3 electrolyte at 960 °C to elucidate the corrosion mechanisms of this type of partially inert anode for the production of aluminum or aluminum alloys. Furthermore, the effects of the geometrical structure of the Cu phase on the thermal corrosion behavior of Cu 2 O/Cu cermet in the electrolyte were investigated as well. The thermal corrosion rate was evaluated by the weight loss method and the results show that the samples prepared with branch-like Cu have higher thermal corrosion rate than those prepared with spherical Cu, and the corrosion rate increases with decreasing size and increasing filling content of Cu phase. The calculated corrosion rate

  3. Lung injury induced by TiO2 nanoparticles depends on their structural features: size, shape, crystal phases, and surface coating.

    Science.gov (United States)

    Wang, Jiangxue; Fan, Yubo

    2014-12-03

    With the rapid development of nanotechnology, a variety of engineered nanoparticles (NPs) are being produced. Nanotoxicology has become a hot topic in many fields, as researchers attempt to elucidate the potential adverse health effects of NPs. The biological activity of NPs strongly depends on physicochemical parameters but these are not routinely considered in toxicity screening, such as dose metrics. In this work, nanoscale titanium dioxide (TiO2), one of the most commonly produced and widely used NPs, is put forth as a representative. The correlation between the lung toxicity and pulmonary cell impairment related to TiO2 NPs and its unusual structural features, including size, shape, crystal phases, and surface coating, is reviewed in detail. The reactive oxygen species (ROS) production in pulmonary inflammation in response to the properties of TiO2 NPs is also briefly described. To fully understand the potential biological effects of NPs in toxicity screening, we highly recommend that the size, crystal phase, dispersion and agglomeration status, surface coating, and chemical composition should be most appropriately characterized.

  4. Acute toxicity of two CdSe/ZnSe quantum dots with different surface coating in Daphnia magna under various light conditions.

    Science.gov (United States)

    Lee, Jiyoun; Ji, Kyunghee; Kim, Jungkon; Park, Chansik; Lim, Kook Hee; Yoon, Tae Hyun; Choi, Kyungho

    2010-12-01

    With an increasing use of quantum dots (QDs) in many applications, their potential hazard is of growing concern. However, little is known about their ecotoxicity, especially in vivo. In the present study, we employed freshwater macroinvertebrate, Daphnia magna, to evaluate toxicity characteristics of cadmium selenide/zinc selenide (CdSe/ZnSe) in relation to surface coatings, e.g., mercaptopropionic acid QD ((MPA)QD), and gum arabic/tri-n-octylphosphine oxide QD ((GA/TOPO)QD), and light conditions, i.e., dark, fluorescent light, environmental level of ultraviolet (UV) light, and sunlight. The results of the present study showed that D. magna was more susceptible to (GA/TOPO)QD exposure compared to (MPA)QD. The surface coating of QD appeared to determine the stability of QDs and hence the toxicity, potentially by size change of or the release of toxic components from QDs. However, (GA/TOPO)QD was still less toxic than the equivalent level of CdCl₂. The toxicity of all the tested compounds increased by changing the light condition from dark to white fluorescence to UV-B light, and to natural sunlight. The effect of light condition on QDs toxicity could also be explained by photostability of the QDs, which would affect size of the particle, release of toxic component ions, and generation of reactive oxygen species. Considering increasing use of QDs in various applications, their environmental fates and corresponding toxic potentials deserve further investigation. Copyright © 2009 Wiley Periodicals, Inc.

  5. Determination of poisoning schemes for the innovating fuels reactivity. Application to plutonium CERCER and CERMET control; Determination de schemas d'empoisonnement pour le controle de la reactivite de combustibles innovants. Application au Cercer et Cermet au plutonium

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, St

    2000-03-01

    In the framework of the plutonium production optimization in the PWR, many solutions are studied to decrease or recycle the plutonium of the nuclear fuels. Among these solutions, the inert matrix fuels (IMF) are proposed in this thesis. In seven chapters the author presents, the context and the state of the art, the different matrix, the calculi codes such as APOLLO2 or TRIPOLI4 needed to the neutronic analysis, the different fuel assemblies (CERMET UO{sub 2}, MOX, PuO{sub 2} and PuO{sub 2}-UO{sub 2}), the efficiency of the control rods in the case of the PWR, the cross sections problem, preliminary reflexions on critical accidents. (A.L.B.)

  6. Advanced cutting techniques: laser and fissuration cutting

    International Nuclear Information System (INIS)

    Perrin, J.; Tanis, G.

    1984-01-01

    The aim of this study is to develop a new method for cutting metal components of nuclear power plants, which produces virtually no secondary waste. In this method, a controlled intergranular fissure is produced in a heated area of the component by the addition of a molten material which gives rise to the formation of brittle compounds. With the presence of molten metal, the material or alloys in which we have tension stresses can have a brittle intergranular failure. Generally the failure occurs in a defined temperature range. The tension stresses are created by the thermal gradient induced during the local heating. At the same time, the molten metal is added. Our work has been developed in two directions: Study on the maximum thickness (presently it is potentially possible to cut thick sheets up to 100 mm); dismantling of nuclear parts as tubes, cans, hot cell walls (we are on the beginning of the development in this field of work). (author)

  7. Cutting hospital costs without cutting staff.

    Science.gov (United States)

    Ortiz, John P

    2011-10-01

    A hospital that is seeking ways to cut costs without compromising care should resist the temptation to lay off staff and instead make it a priority to improve efficiencies. This approach requires a formal program to identify and analyze all of the hospital's processes. The focus of the analysis should be to determine which activities are being performed efficiently, which are being performed inefficiently, and which are unnecessary. This effort will achieve the greatest success if it is customer-centric.

  8. Advanced cutting techniques: laser and fissuration cutting

    International Nuclear Information System (INIS)

    Migliorati, B.; Gay, P.

    1984-01-01

    Experimental tests have been performed using CO 2 laser with output power 1 to 15 kW to evaluate the effect of varying the following parameters: material (carbon steel Fe 42 C, stainless steel AISI 304, concrete), laser power, beam characteristics, work piece velocity, gas type and distribution on the laser interaction zone. In the case of concrete, drilling depths of 80 mm were obtained in a few seconds using a 10 kW laser beam. Moreover pieces of 160 mm were cut at 0.01 meters per minute. Results with carbon steel indicated maximum thicknesses of 110 mm, cut at 0.01 meters per minute with 10 kW, depths about 20% lower were obtained with the AISI 304 stainless steel. A parallel investigation was aimed at characterizing particulate emission during the laser cutting process. At the end of the research it was possible to elaborate a preliminary proposal concerning a laser based dismantling system for the application to a typical Nuclear Power Station. (author)

  9. Laser Cutting, Development Trends

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    1999-01-01

    In this paper a short review of the development trends in laser cutting will be given.The technology, which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal, as it will expand in heavy industry and in cutting...... of 3-dimensional shapes.The CO2-laser will also in the near future be the dominating laser source in the market, although the new developments in ND-YAG-lasers opens for new possibilities for this laser type....

  10. Boron-carbide-aluminum and boron-carbide-reactive metal cermets. [B/sub 4/C-Al

    Science.gov (United States)

    Halverson, D.C.; Pyzik, A.J.; Aksay, I.A.

    1985-05-06

    Hard, tough, lighweight boron-carbide-reactive metal composites, particularly boron-carbide-aluminum composites, are produced. These composites have compositions with a plurality of phases. A method is provided, including the steps of wetting and reacting the starting materials, by which the microstructures in the resulting composites can be controllably selected. Starting compositions, reaction temperatures, reaction times, and reaction atmospheres are parameters for controlling the process and resulting compositions. The ceramic phases are homogeneously distributed in the metal phases and adhesive forces at ceramic-metal interfaces are maximized. An initial consolidated step is used to achieve fully dense composites. Microstructures of boron-carbide-aluminum cermets have been produced with modules of rupture exceeding 110 ksi and fracture toughness exceeding 12 ksi..sqrt..in. These composites and methods can be used to form a variety of structural elements.

  11. Cermets Ni-GDC para su uso como ánodos en IT-SOFC basadas en electrolitos GDC

    Directory of Open Access Journals (Sweden)

    Gil, V.

    2008-08-01

    Full Text Available The purpose of this work is to investigate the possible solid state reactions between the NiO-Ce0.9Gd0.1O1.95 (NiO-GDC composites with 50% wt NiO, and cermets Ni- Ce0.9Gd0.1O1.95 (Ni-GDC with 39 vol. % of Ni, and electrolyte solid solutions based on Ce0.9Gd0.1O1.95 (GDC employing the X-ray diffraction technique. At the same time the thermochemical and thermomechanical compatibility between these materials was established. Results obtained from SEM and EDAX analysis showed that the electrolyte based on ceria (GDC and the anode based on nickel-ceria cermet (Ni-GDC present good adhesion and well defined interfaces. No reactive phases and other type of defects were detected. This study showed that both materials, Ni-GDC and GDC are thermochemical and thermomechanically compatible.

    El objetivo de este trabajo es estudiar en un amplio rango de temperaturas (1000-1450ºC y mediante difracción de rayos-X (DRX las posibles reacciones en estado sólido que pueden tener lugar en las regiones interfaciales de sistemas constituidos por composites NiO-Ce0.9Gd0.1O1.95 (NiO-GDC con un 50% en peso de NiO, y de Cermets Ni-Ce0.9Gd0.1O1.95 (Ni-GDC con un 39% en volumen Ni, y electrolitos basados en soluciones sólidas Ce0.9Gd0.1O1.95 (GDC. Y así mismo, estudiar la compatibilidad termoquímica y termomecánica entre los distintos materiales cerámicos que constituyen los sistemas electrolito/ánodo. Se confirma mediante MEB y análisis EDAX que los sistemas cosinterizados entre 1350 y 1400ºC durante 2h y constituidos por un electrolito basado en ceria (GDC y un ánodo basado en un cermet níquel-ceria (Ni-GDC, presentan una buena adherencia entre capas, sin la formación de defectos y sin la presencia de interdifusión de especies a lo

  12. Experimental testing of exchangeable cutting inserts cutting ability

    OpenAIRE

    Čep, Robert; Janásek, Adam; Čepová, Lenka; Petrů, Jana; Hlavatý, Ivo; Car, Zlatan; Hatala, Michal

    2013-01-01

    The article deals with experimental testing of the cutting ability of exchangeable cutting inserts. Eleven types of exchangeable cutting inserts from five different manufacturers were tested. The tested cutting inserts were of the same shape and were different especially in material and coating types. The main aim was both to select a suitable test for determination of the cutting ability of exchangeable cutting inserts and to design such testing procedure that could make it possible...

  13. Short-cut math

    CERN Document Server

    Kelly, Gerard W

    1984-01-01

    Clear, concise compendium of about 150 time-saving math short-cuts features faster, easier ways to add, subtract, multiply, and divide. Each problem includes an explanation of the method. No special math ability needed.

  14. Laser cutting system

    Science.gov (United States)

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  15. Cutting and Self-Harm

    Science.gov (United States)

    ... Your feelings Feeling sad Cutting and self-harm Cutting and self-harm Self-harm, sometimes called self- ... There are many types of self-injury, and cutting is one type that you may have heard ...

  16. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Affonso Lourenco; Evren Ozbayoglu; Lei Zhou

    2002-01-30

    This is the second quarterly progress report for Year 3 of the ACTS project. It includes a review of progress made in: (1) Flow Loop development and (2) research tasks during the period of time between Oct 1, 2001 and Dec. 31, 2001. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 3: Addition of a Cuttings Injection/Collection System), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (d) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (e) Research on instrumentation tasks to measure: Cuttings concentration and distribution in a flowing slurry (Task 11), and Foam properties while transporting cuttings. (Task 12), (f) Development of a Safety program for the ACTS Flow Loop. Progress on a comprehensive safety review of all flow-loop components and operational procedures. (Task 1S). (g) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members.

  17. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Mengjiao Yu; Ramadan Ahmed; Mark Pickell; Len Volk; Lei Zhou; Zhu Chen; Aimee Washington; Crystal Redden

    2003-09-30

    The Quarter began with installing the new drill pipe, hooking up the new hydraulic power unit, completing the pipe rotation system (Task 4 has been completed), and making the SWACO choke operational. Detailed design and procurement work is proceeding on a system to elevate the drill-string section. The prototype Foam Generator Cell has been completed by Temco and delivered. Work is currently underway to calibrate the system. Literature review and preliminary model development for cuttings transportation with polymer foam under EPET conditions are in progress. Preparations for preliminary cuttings transport experiments with polymer foam have been completed. Two nuclear densitometers were re-calibrated. Drill pipe rotation system was tested up to 250 RPM. Water flow tests were conducted while rotating the drill pipe up to 100 RPM. The accuracy of weight measurements for cuttings in the annulus was evaluated. Additional modifications of the cuttings collection system are being considered in order to obtain the desired accurate measurement of cuttings weight in the annular test section. Cutting transport experiments with aerated fluids are being conducted at EPET, and analyses of the collected data are in progress. The printed circuit board is functioning with acceptable noise level to measure cuttings concentration at static condition using ultrasonic method. We were able to conduct several tests using a standard low pass filter to eliminate high frequency noise. We tested to verify that we can distinguish between different depths of sand in a static bed of sand. We tested with water, air and a mix of the two mediums. Major modifications to the DTF have almost been completed. A stop-flow cell is being designed for the DTF, the ACTF and Foam Generator/Viscometer which will allow us to capture bubble images without the need for ultra fast shutter speeds or microsecond flash system.

  18. How Much Surface Coating of Hydrophobic Azithromycin Is Sufficient to Prevent Moisture-Induced Decrease in Aerosolisation of Hygroscopic Amorphous Colistin Powder?

    Science.gov (United States)

    Zhou, Qi Tony; Loh, Zhi Hui; Yu, Jiaqi; Sun, Si-Ping; Gengenbach, Thomas; Denman, John A; Li, Jian; Chan, Hak-Kim

    2016-09-01

    Aerosolisation performance of hygroscopic particles of colistin could be compromised at elevated humidity due to increased capillary forces. Co-spray drying colistin with a hydrophobic drug is known to provide a protective coating on the composite particle surfaces against moisture-induced reduction in aerosolisation performance; however, the effects of component ratio on surface coating quality and powder aerosolisation at elevated relative humidities are unknown. In this study, we have systematically examined the effects of mass ratio of hydrophobic azithromycin on surface coating quality and aerosolisation performance of the co-spray dried composite particles. Four combination formulations with varying drug ratios were prepared by co-spray drying drug solutions. Both of the drugs in each combination formulation had similar in vitro deposition profiles, suggesting that each composite particle comprises two drugs in the designed mass ratio, which is supported by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) data. XPS and ToF-SIMS measurements also revealed that 50% by weight (or 35% by molecular fraction) of azithromycin in the formulation provided a near complete coating of 96.5% (molar fraction) on the composite particle surface, which is sufficient to prevent moisture-induced reduction in fine particle fraction (FPF)recovered and FPFemitted. Higher azithromycin content did not increase coating coverage, while contents of azithromycin lower than 20% w/w did not totally prevent the negative effects of humidity on aerosolisation performance. This study has highlighted that a critical amount of azithromycin is required to sufficiently coat the colistin particles for short-term protection against moisture.

  19. How much surface coating of hydrophobic azithromycin is sufficient to prevent moisture-induced decrease in aerosolisation of hygroscopic colistin powder?

    Science.gov (United States)

    Zhou, Qi (Tony); Loh, Zhi Hui; Yu, Jiaqi; Sun, Si-ping; Gengenbach, Thomas; Denman, John A.; Li, Jian; Chan, Hak-Kim

    2017-01-01

    Aerosolisation performance of hygroscopic particles of colistin could be compromised at elevated humidity due to increased capillary forces. Co-spray drying colistin with a hydrophobic drug is known to provide a protective coating on the composite particle surfaces against moisture-induced reduction in aerosolisation performance; however, the effects of component ratio on surface coating quality and powder aerosolisation at elevated relative humidities are unknown. In this study, we have systematically examined the effects of mass ratio of hydrophobic azithromycin on surface coating quality and aerosolisation performance of the co-spray dried composite particles. Four combination formulations with varying drug ratios were prepared by co-spray drying drug solutions. Both of the drugs in each combination formulation had similar in vitro deposition profiles, suggesting that each composite particle comprise two drugs in the designed mass ratio, which is supported by XPS and ToF-SIMS data. XPS and ToF-SIMS measurements also revealed that 50 % by weight (or 35 % by molecular fraction) of azithromycin in the formulation provided a near-complete coating of 96.5 % (molar fraction) on the composite particle surface, which is sufficient to prevent moisture-induced reduction in FPFrecovered and FPFemitted. Higher azithromycin content did not increase coating coverage, while contents of azithromycin lower than 20 %w/w did not totally prevent the negative effects of humidity on aerosolisation performance. This study has highlighted that a critical amount of azithromycin is required to sufficiently coat the colistin particles for short-term protection against moisture. PMID:27255350

  20. Sequencing and Analysis of the Pseudomonas fluorescens GcM5-1A Genome: A Pathogen Living in the Surface Coat of Bursaphelenchus xylophilus.

    Directory of Open Access Journals (Sweden)

    Kai Feng

    Full Text Available It is known that several bacteria are adherent to the surface coat of pine wood nematode (Bursaphelenchus xylophilus, but their function and role in the pathogenesis of pine wilt disease remains debatable. The Pseudomonas fluorescens GcM5-1A is a bacterium isolated from the surface coat of pine wood nematodes. In previous studies, GcM5-1A was evident in connection with the pathogenicity of pine wilt disease. In this study, we report the de novo sequencing of the GcM5-1A genome. A 600-Mb collection of high-quality reads was obtained and assembled into sequence contigs spanning a 6.01-Mb length. Sequence annotation predicted 5,413 open reading frames, of which 2,988 were homologous to genes in the other four sequenced P. fluorescens isolates (SBW25, WH6, Pf0-1 and Pf-5 and 1,137 were unique to GcM5-1A. Phylogenetic studies and genome comparison revealed that GcM5-1A is more closely related to SBW25 and WH6 isolates than to Pf0-1 and Pf-5 isolates. Towards study of pathogenesis, we identified 79 candidate virulence factors in the genome of GcM5-1A, including the Alg, Fl, Waa gene families, and genes coding the major pathogenic protein fliC. In addition, genes for a complete T3SS system were identified in the genome of GcM5-1A. Such systems have proved to play a critical role in subverting and colonizing the host organisms of many gram-negative pathogenic bacteria. Although the functions of the candidate virulence factors need yet to be deciphered experimentally, the availability of this genome provides a basic platform to obtain informative clues to be addressed in future studies by the pine wilt disease research community.

  1. Improved cutting performance in high power laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    2003-01-01

    Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described.......Recent results in high power laser cutting especially with focus on cutting of mild grade steel types for shipbuilding are described....

  2. A Comparative Study on SiC-B4C-Si Cermet Prepared by Pressureless Sintering and Spark Plasma Sintering Methods

    Science.gov (United States)

    Sahani, P.; Karak, S. K.; Mishra, B.; Chakravarty, D.; Chaira, D.

    2016-06-01

    Silicon carbide (SiC)-boron carbide (B4C) based cermets were doped with 5, 10, and 20 wt pct Silicon (Si) and their sinterability and properties were investigated for conventional sintering at 2223 K (1950 °C) and spark plasma sintering (SPS) at 1623 K (1350 °C). An average particle size of ~3 µm was obtained after 10 hours of milling. There is an enhancement of Vickers microhardness in the 10 wt pct Si sample from 18.10 in conventional sintering to 27.80 GPa for SPS. The relative density, microhardness, and indentation fracture toughness of the composition SiC60(B4C)30Si10 fabricated by SPS are 98 pct, 27.80 GPa, and 3.8 MPa m1/2, respectively. The novelty of the present study is to tailor the wettability and ductility of the cermet by addition of Si into the SiC-B4C matrix. Better densification with improved properties is achieved for cermets consolidated by SPS at lower temperatures than conventional sintering.

  3. Underwater plasma arc cutting

    International Nuclear Information System (INIS)

    Leautier, R.; Pilot, G.

    1991-01-01

    This report describes the work done to develop underwater plasma arc cutting techniques, to characterise aerosols from cutting operations on radioactive and non-radioactive work-pieces, and to develop suitable ventilation and filtration techniques. The work has been carried out in the framework of a contract between CEA-CEN Cadarache and the Commission of European Communities. Furthermore, this work has been carried out in close cooperation with CEA-CEN Saclay mainly for secondary emissions and radioactive analysis. The contract started in May 1986 and was completed in December 1988 by a supplementary agreement. This report has been compiled from several progress reports submitted during the work period, contains the main findings of the work and encloses the results of comparative tests on plasma arc cutting

  4. Theoretical Models for Orthogonal Cutting

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    This review of simple models for orthogonal cutting was extracted from: “L. De Chiffre: Metal Cutting Mechanics and Applications, D.Sc. Thesis, Technical University of Denmark, 1990.”......This review of simple models for orthogonal cutting was extracted from: “L. De Chiffre: Metal Cutting Mechanics and Applications, D.Sc. Thesis, Technical University of Denmark, 1990.”...

  5. Radial cutting torch

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, M.C.

    1997-01-08

    The project`s aim is to complete development of the Radial Cutting Torch, a pyrotechnic cutter, for use in all downhole tubular cutting operations in the petroleum industry. Project objectives are to redesign and pressure test nozzle seals to increase product quality, reliability, and manufacturability; improve the mechanical anchor to increase its temperature tolerance and its ability to function in a wider variety of wellbore fluids; and redesign and pressure test the RCT nozzle for operation at pressures from 10 to 20 ksi. The proposal work statement is included in the statement of work for the grant via this reference.

  6. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Stefan Miska; Troy Reed; Ergun Kuru

    2004-09-30

    The Advanced Cuttings Transport Study (ACTS) was a 5-year JIP project undertaken at the University of Tulsa (TU). The project was sponsored by the U.S. Department of Energy (DOE) and JIP member companies. The objectives of the project were: (1) to develop and construct a new research facility that would allow three-phase (gas, liquid and cuttings) flow experiments under ambient and EPET (elevated pressure and temperature) conditions, and at different angle of inclinations and drill pipe rotation speeds; (2) to conduct experiments and develop a data base for the industry and academia; and (3) to develop mechanistic models for optimization of drilling hydraulics and cuttings transport. This project consisted of research studies, flow loop construction and instrumentation development. Following a one-year period for basic flow loop construction, a proposal was submitted by TU to the DOE for a five-year project that was organized in such a manner as to provide a logical progression of research experiments as well as additions to the basic flow loop. The flow loop additions and improvements included: (1) elevated temperature capability; (2) two-phase (gas and liquid, foam etc.) capability; (3) cuttings injection and removal system; (4) drill pipe rotation system; and (5) drilling section elevation system. In parallel with the flow loop construction, hydraulics and cuttings transport studies were preformed using drilling foams and aerated muds. In addition, hydraulics and rheology of synthetic drilling fluids were investigated. The studies were performed under ambient and EPET conditions. The effects of temperature and pressure on the hydraulics and cuttings transport were investigated. Mechanistic models were developed to predict frictional pressure loss and cuttings transport in horizontal and near-horizontal configurations. Model predictions were compared with the measured data. Predominantly, model predictions show satisfactory agreements with the measured data. As a

  7. Cutting Cakes Carefully

    Science.gov (United States)

    Hill, Theodore P.; Morrison, Kent E.

    2010-01-01

    This paper surveys the fascinating mathematics of fair division, and provides a suite of examples using basic ideas from algebra, calculus, and probability which can be used to examine and test new and sometimes complex mathematical theories and claims involving fair division. Conversely, the classical cut-and-choose and moving-knife algorithms…

  8. Cuts, Scratches, and Scrapes

    Science.gov (United States)

    ... Body Mind Sexual Health Food & Fitness Diseases & Conditions Infections Drugs & Alcohol School & Jobs Sports Expert Answers (Q&A) Staying Safe Videos for Educators Search English Español Cuts, Scratches, and ... Infection Signs of Infection Print en español Cortes, rasguños ...

  9. Petrographic drill cutting analysis

    Energy Technology Data Exchange (ETDEWEB)

    Thom, R. [Core Laboratories Canada Ltd., Calgary, AB (Canada)

    1999-11-01

    Some of the diagnostic tools which are available to determine valuable reservoir rock information from drill cuttings were described. For example, valuable information can be obtained from drill cuttings and petrographic thin sections regarding mineralogy, facies, pore systems, reservoir quality and fluid sensitivity. This paper described the best ways to pick representative drill cuttings from vials. Colour and texture are among the most important determining factors. New guidelines from the Alberta Energy and Utilities Board have made it possible to obtain thin sections from drill cuttings from a competitor`s wells. Up to 12 chips from each vial can be removed for thin section scanning electron microscopy (SEM) analysis. X-ray diffraction (XRD) analysis of drill chips is not recommended because it is usually not possible to obtain enough sample material. Another powerful tool to investigate and characterize pore systems is the Mercury Injection Capillary Pressure technique. This technique makes it possible to characterize the pore system and to determine pore throat size distribution, permeability/porosity, producible reserves, capillary pressure, effective versus non-effective porosity, irreducible water saturation, and height above free water. The most reliable and valuable information is obtained from sandstone and carbonate aggregate chips in which the pore system is preserved. It was also noted that core porosity can be empirically derived if a trend line is constructed using sections prepared from an equivalent cored zone. Permeability can be derived in much the same way. 9 figs.

  10. Simultaneous Cake Cutting

    DEFF Research Database (Denmark)

    Balkanski, Eric; Branzei, Simina; Kurokawa, David

    2014-01-01

    We introduce the simultaneous model for cake cutting (the fair allocation of a divisible good), in which agents simultaneously send messages containing a sketch of their preferences over the cake. We show that this model enables the computation of divisions that satisfy proportionality — a popular...

  11. On the nature of groundwater flow paths: Observations at fractures and fracture coating at road-cuts

    International Nuclear Information System (INIS)

    Lindberg, A.; Hellmuth, K.-H.

    2001-01-01

    Preliminary investigations were conducted at fractures and their surface coatings exposed along recently quarried road-cuts to the north and east of Helsinki. While (sub)horizontal fractures were usually rare at depths more than a few meters, (sub)vertical fractures were dominating. Fracture fillings/coatings were mostly absent in the formers and generally thin in the latters. Often these fillings/coatings were representative for processes which occurred in the far past at conditions others than present ambient ones. But, on the other hand only a few cases of more intense rock matrix alteration in connection with these processes were observed. Post-glacial weathering has caused at many of the investigated sites surficial oxidation of Fe(II)-rich minerals which has led to mostly thin coatings of fracture surfaces by soft amorphous Fe(III)-oxyhydroxides. Surface coatings were generally homogeneous with fairly even surface structures. It was found that at road-cuts huge areas of undamaged fracture surfaces were accessable to investigations. These can serve for demonstration purposes for the nature of contact surface between groundwater and rock. Despite some oxidation, these exposures give a fairly representative impression of the situation at greater depth where similar fracture types were reported in repository site investigations. (orig.)

  12. Core Cutting Test with Vertical Rock Cutting Rig (VRCR)

    Science.gov (United States)

    Yasar, Serdar; Osman Yilmaz, Ali

    2017-12-01

    Roadheaders are frequently used machines in mining and tunnelling, and performance prediction of roadheaders is important for project economics and stability. Several methods were proposed so far for this purpose and, rock cutting tests are the best choice. Rock cutting tests are generally divided into two groups which are namely, full scale rock cutting tests and small scale rock cutting tests. These two tests have some superiorities and deficiencies over themselves. However, in many cases, where rock sampling becomes problematic, small scale rock cutting test (core cutting test) is preferred for performance prediction, since small block samples and core samples can be conducted to rock cutting testing. Common problem for rock cutting tests are that they can be found in very limited research centres. In this study, a new mobile rock cutting testing equipment, vertical rock cutting rig (VRCR) was introduced. Standard testing procedure was conducted on seven rock samples which were the part of a former study on cutting rocks with another small scale rock cutting test. Results showed that core cutting test can be realized successfully with VRCR with the validation of paired samples t-test.

  13. Influence of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires

    Science.gov (United States)

    Asiry, Moshabab A.; AlShahrani, Ibrahim; Almoammar, Salem; Durgesh, Bangalore H.; Kheraif, Abdulaziz A. Al; Hashem, Mohamed I.

    2018-02-01

    Aim. To investigate the effect of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires Methods. Three different coated (Epoxy, polytetrafluoroethylene (PTFE) and rhodium) and one uncoated Ni-Ti archwires were evaluated in the present study. Surface roughness (Ra) was assessed using a non-contact surface profilometer. The mechanical properties (nano-hardness and elastic modulus) were measured using a nanoindenter. Bacterial adhesion assays were performed using Streptococcus mutans (MS) and streptococcus sobrinus (SS) in an in-vitro set up. The data obtained were analyzed using analyses of variance, Tukey’s post hoc test and Pearson’s correlation coefficient test. Result. The highest Ra values (1.29 ± 0.49) were obtained for epoxy coated wires and lowest Ra values (0.29 ± 0.16) were obtained for the uncoated wires. No significant differences in the Ra values were observed between the rhodium coated and uncoated archwires (P > 0.05). The highest nano-hardness (3.72 ± 0.24) and elastic modulus values (61.15 ± 2.59) were obtained for uncoated archwires and the lowest nano-hardness (0.18 ± 0.10) and elastic modulus values (4.84 ± 0.65) were observed for epoxy coated archwires. No significant differences in nano-hardness and elastic modulus values were observed between the coated archwires (P > 0.05). The adhesion of Streptococcus mutans (MS) to the wires was significantly greater than that of streptococcus sobrinus (SS). The epoxy coated wires demonstrated an increased adhesion of MS and SS and the uncoated wires demonstrated decreased biofilm adhesion. The Spearman correlation test showed that MS and SS adhesion was positively correlated with the surface roughness of the wires. Conclusion. The different surface coatings significantly influence the roughness, nano-mechanical properties and biofilm adhesion parameters of the archwires. The

  14. Experimental investigations of the frictional and wear behavior of tungsten carbide cermet ball bearings under axial load in liquid sodium

    International Nuclear Information System (INIS)

    Kleefeldt, K.W.

    1976-01-01

    The paper describes part of the R and D work performed on ball bearings operated in a liquid sodium environment and tested under conditions which are felt to be representative for high precision mechanisms in LMFBR's. After a short introduction, mainly dealing with the experimental results of other authors, a description will be given of the test facility, the test procedure, the ball bearings and the basis for the selection of the materials. The paper covers the experimental phase, which has been carried out in two steps. In the first phase material screening tests demonstrated the tungsten-carbide-cobalt cermet to be superior to the other materials tested with respect to friction and wear. This material, therefore, was selected for a more detailed parameter test programme during phase 2. Up to now a series of tests have been performed with bearing load and speed as parameters, indicating that fatigue is the life limiting factor. It shows that a life-load relationship, similar to that known for conventional ball bearing technology, also seems appropriate for the test conditions and environment investigated here

  15. Laser nanostructured Co nanocylinders-Al{sub 2}O{sub 3} cermets for enhanced & flexible solar selective absorbers applications

    Energy Technology Data Exchange (ETDEWEB)

    Karoro, A., E-mail: angela@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Nuru, Z.Y.; Kotsedi, L.; Bouziane, Kh. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa); Mothudi, B.M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Physics Dept., University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Western Cape (South Africa)

    2015-08-30

    Highlights: • Co-Al{sub 2}O{sub 3} was synthesized by electrodeposition & femtosecond laser structuring. • The ultrafast laser structuring significantly increases the solar absorption. • Co-Al{sub 2}O{sub 3} exhibited 0.98 solar absorptance and 0.03 thermal emittance. - Abstract: We report on the structural and optical properties of laser surface structured Co nanocylinders-Al{sub 2}O{sub 3} cermets on flexible Aluminium substrate for enhanced solar selective absorbers applications. This new family of solar selective absorbers coating consisting of Co nanocylinders embedded into nanoporous alumina template which were produced by standard electrodeposition and thereafter submitted to femtosecond laser surface structuring. While their structural and chemical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and atomic force microscopy, their optical characteristics were investigated by specular & diffuse reflectance. The optimized samples exhibit an elevated optical absorptance α(λ) above 98% and an emittance ε(λ) ∼0.03 in the spectral range of 200–1100 nm. This set of values was suggested to be related to several surface and volume phenomena such as light trapping, plasmon surface effect as well as angular dependence of light reflection induced by the ultrafast laser multi-scale structuring.

  16. Microscopic Examination of Cold Spray Cermet Sn+In2O3 Coatings for Sputtering Target Materials

    Directory of Open Access Journals (Sweden)

    M. Winnicki

    2017-01-01

    Full Text Available Low-pressure cold spraying is a newly developed technology with high application potential. The aim of this study was to investigate potential application of this technique for producing a new type of transparent conductive oxide films target. Cold spraying technique allows the manufacture of target directly on the backing plate; therefore the proposed sputtering target has a form of Sn+In2O3 coating sprayed onto copper substrate. The microstructure and properties of the feedstock powder prepared using three various methods as well as the deposited ones by low-pressure cold spraying coatings were evaluated, compared, and analysed. Produced cermet Sn+In2O3 targets were employed in first magnetron sputtering process to deposit preliminary, thin, transparent conducting oxide films onto the glass substrates. The resistivity of obtained preliminary films was measured and allows believing that fabrication of TCO (transparent conducting oxide films using targets produced by cold spraying is possible in the future, after optimization of the deposition conditions.

  17. Cutting to the chase

    International Nuclear Information System (INIS)

    Snieckus, D.

    2001-01-01

    This article reports on the development of the cost effective abrasive cutting Sabre system which came as a result of UWG's work on the decommissioning of the Phillips' Maureen wells and adds to UWG's 'total severance solution' tools. The advantages of the system are highlighted and include the ability to operate from a platform or diving support vessel, to cut internal cases, and to eliminate the use of environmentally damaging explosives and the need to operate from a rig. The new Mark II version of the Sabre designed to work at greater depths of water, the range of the severance tools, UWG's well abandonment hole assembly system, and its aim to enter the Gulf of Mexico market are discussed. Details are given of the decommissioning of the Schwedeneck-See platforms in Kiel Bay off Germany and the Phillips' UK decommissioning plans for the Maureen platform

  18. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Ergun Kuru; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira; Neelima Godugu

    2000-07-30

    ACTS flow loop is now operational under elevated pressure and temperature. Currently, experiments with synthetic based drilling fluids under pressure and temperature are being conducted. Based on the analysis of Fann 70 data, empirical correlations defining the shear stress as a function of temperature, pressure and the shear rate have been developed for Petrobras synthetic drilling fluids. PVT equipment has been modified for testing Synthetic oil base drilling fluids. PVT tests with Petrobras Synthetic base mud have been conducted and results are being analyzed Foam flow experiments have been conducted and the analysis of the data has been carried out to characterize the rheology of the foam. Comparison of pressure loss prediction from the available foam hydraulic models and the test results has been made. Cuttings transport experiments in horizontal annulus section have been conducted using air, water and cuttings. Currently, cuttings transport tests in inclined test section are being conducted. Foam PVT analysis tests have been conducted. Foam stability experiments have also been conducted. Effects of salt and oil concentration on the foam stability have been investigated. Design of ACTS flow loop modification for foam and aerated mud flow has been completed. A flow loop operation procedure for conducting foam flow experiments under EPET conditions has been prepared Design of the lab-scale flow loop for dynamic foam characterization and cuttings monitoring instrumentation tests has been completed. The construction of the test loop is underway. As part of the technology transport efforts, Advisory Board Meeting with ACTS-JIP industry members has been organized on May 13, 2000.

  19. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Mark Pickell; Len Volk; Mike Volk; Lei Zhou; Zhu Chen; Crystal Redden; Aimee Washington

    2003-07-30

    This Quarter has been divided between running experiments and the installation of the drill-pipe rotation system. In addition, valves and piping were relocated, and three viewports were installed. Detailed design work is proceeding on a system to elevate the drill-string section. Design of the first prototype version of a Foam Generator has been finalized, and fabrication is underway. This will be used to determine the relationship between surface roughness and ''slip'' of foams at solid boundaries. Additional cups and rotors are being machined with different surface roughness. Some experiments on cuttings transport with aerated fluids have been conducted at EPET. Theoretical modeling of cuttings transport with aerated fluids is proceeding. The development of theoretical models to predict frictional pressure losses of flowing foam is in progress. The new board design for instrumentation to measure cuttings concentration is now functioning with an acceptable noise level. The ultrasonic sensors are stable up to 190 F. Static tests with sand in an annulus indicate that the system is able to distinguish between different sand concentrations. Viscometer tests with foam, generated by the Dynamic Test Facility (DTF), are continuing.

  20. Vortex cutting in superconductors

    Science.gov (United States)

    Vlasko-Vlasov, Vitalii K.; Koshelev, Alexei E.; Glatz, Andreas; Welp, Ulrich; Kwok, Wai-K.

    2015-03-01

    Unlike illusive magnetic field lines in vacuum, magnetic vortices in superconductors are real physical strings, which interact with the sample surface, crystal structure defects, and with each other. We address the complex and poorly understood process of vortex cutting via a comprehensive set of magneto-optic experiments which allow us to visualize vortex patterns at magnetization of a nearly twin-free YBCO crystal by crossing magnetic fields of different orientations. We observe a pronounced anisotropy in the flux dynamics under crossing fields and the filamentation of induced supercurrents associated with the staircase vortex structure expected in layered cuprates, flux cutting effects, and angular vortex instabilities predicted for anisotropic superconductors. At some field angles, we find formation of the vortex domains following a type-I phase transition in the vortex state accompanied by an abrupt change in the vortex orientation. To clarify the vortex cutting scenario we performed time-dependent Ginzburg-Landau simulations, which confirmed formation of sharp vortex fronts observed in the experiment and revealed a left-handed helical instability responsible for the rotation of vortices. This work was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering Division.

  1. Cutting forces during turning with variable depth of cut

    Directory of Open Access Journals (Sweden)

    M. Sadílek

    2016-03-01

    The proposed research for the paper is an experimental work – measuring cutting forces and monitoring of the tool wear on the cutting edge. It compares the turning where standard roughing cycle is used and the turning where the proposed roughing cycle with variable depth of cut is applied.

  2. Performance Testing of Cutting Fluids

    DEFF Research Database (Denmark)

    Belluco, Walter

    The importance of cutting fluid performance testing has increased with documentation requirements of new cutting fluid formulations based on more sustainable products, as well as cutting with minimum quantity of lubrication and dry cutting. Two sub-problems have to be solved: i) which machining...... tests feature repeatability, reproducibility and sensitivity to cutting fluids, and ii) to what extent results of one test ensure relevance to a wider set of machining situations. The present work is aimed at assessing the range of validity of the different testing methods, investigating correlation...... within the whole range of operations, materials, cutting fluids, operating conditions, etc. Cutting fluid performance was evaluated in turning, drilling, reaming and tapping, and with respect to tool life, cutting forces, chip formation and product quality (dimensional accuracy and surface integrity...

  3. Effect of surface coating with magnesium stearate via mechanical dry powder coating approach on the aerosol performance of micronized drug powders from dry powder inhalers.

    Science.gov (United States)

    Zhou, Qi Tony; Qu, Li; Gengenbach, Thomas; Larson, Ian; Stewart, Peter J; Morton, David A V

    2013-03-01

    The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency.

  4. Investigation of the extent of surface coating via mechanofusion with varying additive levels and the influences on bulk powder flow properties.

    Science.gov (United States)

    Zhou, Qi Tony; Qu, Li; Gengenbach, Thomas; Denman, John A; Larson, Ian; Stewart, Peter J; Morton, David A V

    2011-07-15

    The objective of this study was to investigate if the coating extent created by a mechanofusion process corresponded with observed changes in bulk powder properties. A fine lactose powder (approximate median diameter 20 μm) was dry coated with magnesium stearate using from 0.1 to 5% (w/w) content. An ultra-thin coating layer of magnesium stearate was anticipated, but previous attempts to determine such thin layers on these fine particles have had limited success, with poor resolution. In this study, the surface coating was examined using the state-of-the-art XPS and ToF-SIMS systems. The powder flow was characterized by Carr index and shear cell testing. XPS was successfully applied to demonstrate variations in surface coverage, as a function of additive levels, and indicated near complete coating coverage at additive levels of 1% (w/w) and above. ToF-SIMS results supported such coating coverage assessment, and indicated coating uniformly across the fine particle surfaces. The flow metrics employed could then be related to the coating coverage metrics. The mechanofusion process also modified the apparent surface roughness observed by SEM and BET. It was suggested that the changes in the surface chemical composition exerted a more evident and direct impact on the powder cohesion and flow characteristics than the changes in the surface morphological properties after the mechanofusion in this study. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Capillary electrophoresis coupled with inductively coupled mass spectrometry as an alternative to cloud point extraction based methods for rapid quantification of silver ions and surface coated silver nanoparticles.

    Science.gov (United States)

    Qu, Haiou; Mudalige, Thilak K; Linder, Sean W

    2016-01-15

    Speciation and accurate quantification of ionic silver and metallic silver nanoparticles are critical to investigate silver toxicity and to determine the shelf-life of products that contain nano silver under various storage conditions. We developed a rapid method for quantification of silver ions and silver nanoparticles using capillary electrophoresis (CE) interfaced with inductively-coupled plasma mass spectrometry (ICPMS). The addition of 2-mercaptopropionylglycine (tiopronin) to the background electrolyte was used to facilitate the chromatographic separation of ionic silver and maintain the oxidation state of silver. The obtained limits of detection were 0.05 μg kg(-1) of silver nanoparticles and 0.03 μg kg(-1) of ionic silver. Nanoparticles of varied sizes (10-110 nm) with different surface coating, including citrate acid, lipoic acid, polyvinylpyrrolidone and bovine serum albumin (BSA) were successfully analyzed. Particularly good recoveries (>93%) were obtained for both ionic silver and silver nanoparticle in the presence of excess amount of BSA. The method was further tested with six commercially available dietary supplements which varied in concentration and matrix components. The summed values of silver ions and silver nanoparticles correlated well with the total silver concentration determined by ICPMS after acid digestion. This method can serve as an alternative to cloud point extraction technique when the extraction efficiency for protein coated nanoparticles is low. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Remote Laser Cutting of CFRP: Improvements in the Cut Surface

    Science.gov (United States)

    Stock, Johannes; Zaeh, Michael F.; Conrad, Markus

    In the automotive industry carbon fibre reinforced plastics (CFRP) are considered as a future key material to reduce the weight of the vehicle. Therefore, capable production techniques are required to process this material in mass industry. E.g., state of the art methods for cutting are limited by the high tool wear or the feasible feed rate. Laser cutting processes are still under investigation. This paper presents detailed new studies on remote laser cutting of CFRP focusing on the influence of the material properties and the quality of the cut surface. By adding light absorbing soot particles to the resin of the matrix, the cutting process is improved and fewer defects emerge.

  7. Photochemical cutting of fabrics

    Science.gov (United States)

    Piltch, Martin S.

    1994-01-01

    Apparatus for the cutting of garment patterns from one or more layers of fabric. A laser capable of producing laser light at an ultraviolet wavelength is utilized to shine light through a pattern, such as a holographic phase filter, and through a lens onto the one or more layers of fabric. The ultraviolet laser light causes rapid photochemical decomposition of the one or more layers of fabric, but only along the pattern. The balance of the fabric of the one or more layers of fabric is undamaged.

  8. ADVANCED CUTTINGS TRANSPORT STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Stefan Miska; Nicholas Takach; Kaveh Ashenayi

    2004-07-31

    We have tested the loop elevation system. We raised the mast to approximately 25 to 30 degrees from horizontal. All went well. However, while lowering the mast, it moved laterally a couple of degrees. Upon visual inspection, severe spalling of the concrete on the face of the support pillar, and deformation of the steel support structure was observed. At this time, the facility is ready for testing in the horizontal position. A new air compressor has been received and set in place for the ACTS test loop. A new laboratory has been built near the ACTS test loop Roughened cups and rotors for the viscometer (RS300) were obtained. Rheologies of aqueous foams were measured using three different cup-rotor assemblies that have different surface roughness. The relationship between surface roughness and foam rheology was investigated. Re-calibration of nuclear densitometers has been finished. The re-calibration was also performed with 1% surfactant foam. A new cuttings injection system was installed at the bottom of the injection tower. It replaced the previous injection auger. A mechanistic model for cuttings transport with aerated mud has been developed. Cuttings transport mechanisms with aerated water at various conditions were experimentally investigated. A total of 39 tests were performed. Comparisons between the model predictions and experimental measurements show a satisfactory agreement. Results from the ultrasonic monitoring system indicated that we could distinguish between different sand levels. We also have devised ways to achieve consistency of performance by securing the sensors in the caps in exactly the same manner as long as the sensors are not removed from the caps. A preliminary test was conducted on the main flow loop at 100 gpm flow rate and 20 lb/min cuttings injection rate. The measured bed thickness using the ultrasonic method showed a satisfactory agreement with nuclear densitometer readings. Thirty different data points were collected after the test

  9. Cutting the Cord-2

    Science.gov (United States)

    2004-01-01

    This animation shows the view from the rear hazard avoidance cameras on the Mars Exploration Rover Spirit as the rover turns 45 degrees clockwise. This maneuver is the first step in a 3-point turn that will rotate the rover 115 degrees to face west. The rover must make this turn before rolling off the lander because airbags are blocking it from exiting from the front lander petal. Before this crucial turn took place, engineers instructed the rover to cut the final cord linking it to the lander. The turn took around 30 minutes to complete.

  10. Cutting the Cord

    Science.gov (United States)

    2004-01-01

    This animation shows the view from the front hazard avoidance cameras on the Mars Exploration Rover Spirit as the rover turns 45 degrees clockwise. This maneuver is the first step in a 3-point turn that will rotate the rover 115 degrees to face west. The rover must make this turn before rolling off the lander because airbags are blocking it from exiting off the front lander petal. Before this crucial turn could take place, engineers instructed the rover to cut the final cord linking it to the lander. The turn took around 30 minutes to complete.

  11. Can You Cut It?

    DEFF Research Database (Denmark)

    Kjær, Tina; Lillelund, Christoffer Bredo; Moth-Poulsen, Mie

    2017-01-01

    The advent of affordable virtual reality (VR) displays and 360◦ video cameras has sparked an interest in bringing cinematic experiences from the screen and into VR. However, it remains uncertain whether traditional approaches to filmmaking can be directly applied to cinematic VR. Historically......’ sense of disorientation and their ability to follow the story, during exposure to fictional 360◦ films experienced using a head-mounted display. The results revealed no effects of increased cut frequency which leads us to conclude that editing need not pose a problem in relation to cinematic VR, as long...

  12. Detailed impedance characterization of a well performing and durable Ni:CGO infiltrated cermet anode for metal-supported solid oxide fuel cells

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Klemensø, Trine; Blennow Tullmar, Peter

    2012-01-01

    Further knowledge of the novel, well performing and durable Ni:CGO infiltrated cermet anode for metal supported fuel cells has been acquired by means of a detailed impedance spectroscopy study. The anode impedance was shown to consist of three arcs. Porous electrode theory (PET) represented as a ...... of the infiltrated submicron sized particles was surprisingly robust. TEM analysis revealed the nano sized Ni particles to be trapped within the CGO matrix, which along the self limiting grain growth of the CGO seem to be able to stabilize the submicron structured anode....

  13. A study of the microstructure and optical properties of thin lead-dielectric cermet films. Ph.D. Thesis - Va. Polytechnic Inst. and State Univ.

    Science.gov (United States)

    Owen, R. B.

    1972-01-01

    A transmission electron microscopy study involving direct and replicating techniques is directed to a definition of the microstructure of radio frequency-sputtered, thin lead-dielectric cermet films. Once defined, this microstructure is used to obtain theoretical film refractive indices. The Maxwell Garnett theory provides a basis for the theoretical results. Measurements of film transmission and reflectivity are used to obtain rough experimental values for film refractive indices by the Tekucheva method. More exact values are obtained via ellipsometry. The rough Tekucheva values are used to determine the range over which computer calculations interpreting the ellipsometric results must be made. This technique yields accurate values for the film refractive indices.

  14. Tribology and Tribo-Corrosion Aspects of Thermal Sprayed Nanostructured Cermet Coatings (Tribologie en tribocorrosie van thermisch gespoten nanogestructureerde hardmetaal deklagen)

    OpenAIRE

    Basak, Animesh

    2009-01-01

    Table of contents Chapter 1: Introduction 1 1.1 Aim of the study 5 1.2 Outline of the thesis 6 Bibliography 9 Chapter 2: Nanostructured coating: State-of-the-art 11 2.1 Advanced nanostructured coatings for engineering applications 12 2.2 Role of nanostructuring: Grain size dependence on properties 15 2.2.1 Intrinsic properties: Strength and hardness 15 2.2.2 Extrinsic properties: Friction, wear and corrosion 22 2.3 Nanostructured cermet co...

  15. CO2 laser cutting

    CERN Document Server

    Powell, John

    1998-01-01

    The laser has given manufacturing industry a new tool. When the laser beam is focused it can generate one of the world's most intense energy sources, more intense than flames and arcs, though similar to an electron beam. In fact the intensity is such that it can vaporise most known materials. The laser material processing industry has been growing swiftly as the quality, speed and new manufacturing possibilities become better understood. In the fore of these new technologies is the process of laser cutting. Laser cutting leads because it is a direct process substitu­ tion and the laser can usually do the job with greater flexibility, speed and quality than its competitors. However, to achieve these high speeds with high quality con­ siderable know how and experience is required. This information is usually carefully guarded by the businesses concerned and has to be gained by hard experience and technical understanding. Yet in this book John Powell explains in lucid and almost non­ technical language many o...

  16. Leptogenesis: The other cuts

    International Nuclear Information System (INIS)

    Garbrecht, Bjoern

    2011-01-01

    For standard leptogenesis from the decay of singlet right-handed neutrinos, we derive source terms for the lepton asymmetry that are present in a finite density background but absent in the vacuum. These arise from cuts through the vertex correction to the decay asymmetry, where in the loop either the Higgs boson and the right-handed neutrino or the left-handed lepton and the right-handed neutrino are simultaneously on-shell. We evaluate the source terms numerically and use them to calculate the lepton asymmetry for illustrative points in parameter space, where we consider only two right-handed neutrinos for simplicity. Compared to calculations where only the standard cut through the propagators of left-handed lepton and Higgs boson is included, sizable corrections arise when the masses of the right-handed neutrinos are of the same order, but the new sources are found to be most relevant when the decaying right-handed neutrino is heavier than the one in the loop. In that situation, they can yield the dominant contribution to the lepton asymmetry.

  17. Adhesion of Porphyromonas gingivalis and Tannerella forsythia to dentin and titanium with sandblasted and acid etched surface coated with serum and serum proteins - An in vitro study.

    Science.gov (United States)

    Eick, Sigrun; Kindblom, Christian; Mizgalska, Danuta; Magdoń, Anna; Jurczyk, Karolina; Sculean, Anton; Stavropoulos, Andreas

    2017-03-01

    To evaluate the adhesion of selected bacterial strains incl. expression of important virulence factors at dentin and titanium SLA surfaces coated with layers of serum proteins. Dentin- and moderately rough SLA titanium-discs were coated overnight with human serum, or IgG, or human serum albumin (HSA). Thereafter, Porphyromonas gingivalis, Tannerella forsythia, or a six-species mixture were added for 4h and 24h. The number of adhered bacteria (colony forming units; CFU) was determined. Arg-gingipain activity of P. gingivalis and mRNA expressions of P. gingivalis and T. forsythia proteases and T. forsythia protease inhibitor were measured. Coating specimens never resulted in differences exceeding 1.1 log10 CFU, comparing to controls, irrespective the substrate. Counts of T. forsythia were statistically significantly higher at titanium than dentin, the difference was up to 3.7 log10 CFU after 24h (p=0.002). No statistically significant variation regarding adhesion of the mixed culture was detected between surfaces or among coatings. Arg-gingipain activity of P. gingivalis was associated with log10 CFU but not with the surface or the coating. Titanium negatively influenced mRNA expression of T. forsythia protease inhibitor at 24h (p=0.026 uncoated, p=0.009 with serum). The present findings indicate that: a) single bacterial species (T. forsythia) can adhere more readily to titanium SLA than to dentin, b) low expression of T. forsythia protease inhibitor may influence the virulence of the species on titanium SLA surfaces in comparison with teeth, and c) surface properties (e.g. material and/or protein layers) do not appear to significantly influence multi-species adhesion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Air formaldehyde and solvent concentrations during surface coating with acid-curing lacquers and paints in the woodworking and furniture industry.

    Science.gov (United States)

    Thorud, Syvert; Gjolstad, Merete; Ellingsen, Dag G; Molander, Paal

    2005-06-01

    An investigation of contemporary exposure to formaldehyde and organic solvents has been carried out during surface coating with acid-curing lacquers and paints in the Norwegian woodworking and furniture industry over a period of 3 years. The investigation covered 27 factories of different sizes and with different types of production, and totally 557 parallel formaldehyde and solvent samples were collected. The formaldehyde concentration (geometric mean) was 0.15 ppm (range 0.01-1.48 ppm) with about 10% of the samples exceeding the Norwegian occupational exposure limit of 0.5 ppm. The solvent concentration as additive effect (geometric mean) was 0.13 (range 0.0004-5.08) and about 5% of the samples exceeded the Norwegian occupational exposure limit. The most frequently occurring solvents from acid-curing lacquers were n-butyl acetate, ethanol, ethyl acetate and 1-butanol, which were found in 88-98% of the samples. Toluene, n-butyl acetate and 1-butanol were the only solvents with maximum concentrations exceeding their respective occupational exposure limits. Curtain painting machine operators were exposed to the highest concentrations of both formaldehyde (geometric mean 0.51 ppm, range 0.08-1.48 ppm) and organic solvents (additive effect, geometric mean 1.18, range 0.02-5.08). Other painting application work tasks such as automatic and manual spray-painting, manual painting and dip painting, showed on average considerably lower concentrations of both formaldehyde (geometric means 0.07-0.16 ppm) and organic solvents (additive effect, geometric mean 0.02-0.18). Non-painting work tasks also displayed moderate concentrations of formaldehyde (geometric means 0.11-0.17 ppm) and organic solvents (additive effect, geometric mean 0.04-0.07).

  19. After the Ribbon Cutting

    DEFF Research Database (Denmark)

    Hodge, Graeme A.; Boulot, Emille; Duffield, Colin

    2017-01-01

    - to long-term governance arrangements. It finds that although industry interviewees agreed PPP governance had improved significantly, they had differing views on how capable Australian states were in governing PPP and how well this task was being undertaken. They were also split on the adequacy......Much attention has gone towards ‘up-front’ processes when delivering infrastructure public–private partnerships (PPPs), but less on how to best govern after the ribbon is cut and the infrastructure built. This paper identifies the primary contractual and institutional governance challenges arising...... in the medium to long term of PPP concession contracts and explores these governance challenges through interviews with high-level PPP industry insiders. The paper presents new findings on the importance of good public administration for successful PPP operation, and on the interesting evolution of medium...

  20. Manufacturing of zirconia microspheres doped with erbia, yttria and ceria by internal gelation process as a part of a cermet fuel

    International Nuclear Information System (INIS)

    Idemitsu, K.; Arima, T.; Inagaki, Y.; Torikai, S.; Pouchon, M.A.

    2003-01-01

    Zirconium oxide is an inert matrix candidate for the transmutation of plutonium in light water reactor (LWR). The thermal conductivity of cubic zirconia is however lower than the conductivities of UO 2 and MOX. Special designs are therefore necessary to avoid high peaking temperatures close to the melting point in the zirconia pellet. Cermet would be a favorable design to improve the thermal conductivity. The suggested cermet fuel consists of fine plutonium doped stabilized zirconia particles dispersed in a metallic inert matrix. Manufacturing tests on cubic zirconia microspheres were carried out by using the internal gelation process developed at the Paul Scherrer Institute. Gelation was conducted successfully and the sintered spheres had a homogeneous single cubic structure. The lattice parameter of the cubic zirconia was estimated as a function of the Er, Y and Ce atomic fraction using a simplified semi-quantitative formula. On the experimental side, it is necessary to further investigate the ideal fabrication conditions, because some gel spheres were opaque and fragile and most of the sintered spheres were cracked, nicked and porous

  1. The diffuse cut-off

    International Nuclear Information System (INIS)

    2014-09-01

    After having recalled the interest of cut-off practices when consumption is higher than production (a cut-off operator turns out some sources of consumption), this publication more particularly addresses the practice of cut-off in the residential sector, also called diffused cut-off. This practice is based on a temporary reduction of electricity consumption in a great number of small sites (for example, a brief interruption of the electricity supply of radiators, hot water tanks, air conditioning devices in dwellings to reduce the total demand of an area). The three main modalities of valorisation of this cut-off power by the operator are presented. Advantages and drawbacks are discussed, and more particularly the impact of cut-off on thermal comfort

  2. Tungsten monocrystal cutting without distortion

    International Nuclear Information System (INIS)

    Dudkin, A.Yu.; Matveev, I.V.; Cheremisin, S.M.

    1982-01-01

    Electrolyte with high electric current localization, containing 1-3 % KOH and 2-10 % NH 3 , is suggested to use for electrochemical cutting of tungsten. A cutting device is described which includes a cathode feed mechanism based on electric heating and a circuit of automatic control of an interelectrode gap. Laue patterns obtained from a cut surface are practically the same as ones from the initial monocrystal

  3. Laser Cutting of Different Materials

    Directory of Open Access Journals (Sweden)

    Kadir ÇAVDAR

    2013-08-01

    Full Text Available In this paper; in general potential developments and trends of a particular machining field by extensively evaluating present studies of laser beam machining have been discussed. As it is indicated below, technical literatures have been subsumed under five major headlines: Experimental studies, reviews, optimization researches of the cutting parameters, theoretical modelling studies of laser beam cutting and academic studies relating to laser cutting

  4. In vitro and in vivo evaluation of biologically synthesized silver nanoparticles for topical applications: effect of surface coating and loading into hydrogels.

    Science.gov (United States)

    Mekkawy, Aml I; El-Mokhtar, Mohamed A; Nafady, Nivien A; Yousef, Naeima; Hamad, Mostafa A; El-Shanawany, Sohair M; Ibrahim, Ehsan H; Elsabahy, Mahmoud

    2017-01-01

    In the present study, silver nanoparticles (AgNPs) were synthesized via biological reduction of silver nitrate using extract of the fungus Fusarium verticillioides (green chemistry principle). The synthesized nanoparticles were spherical and homogenous in size. AgNPs were coated with polyethylene glycol (PEG) 6000, sodium dodecyl sulfate (SDS), and β-cyclodextrin (β-CD). The averaged diameters of AgNPs were 19.2±3.6, 13±4, 14±4.4, and 15.7±4.8 nm, for PEG-, SDS-, and β-CD-coated and uncoated AgNPs, respectively. PEG-coated AgNPs showed greater stability as indicated by a decreased sedimentation rate of particles in their water dispersions. The antibacterial activities of different AgNPs dispersions were investigated against Gram-positive bacteria (methicillin-sensitive and methicillin-resistant Staphylococcus aureus ) and Gram-negative bacteria ( Escherichia coli ) by determination of the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). MIC and MBC values were in the range of 0.93-7.5 and 3.75-15 µg/mL, respectively, which were superior to the reported values in literature. AgNPs-loaded hydrogels were prepared from the coated-AgNPs dispersions using several gelling agents (sodium carboxymethyl cellulose [Na CMC], sodium alginate, hydroxypropylmethyl cellulose, Pluronic F-127, and chitosan). The prepared formulations were evaluated for their viscosity, spreadability, in vitro drug release, and antibacterial activity, and the combined effect of the type of surface coating and the polymers utilized to form the gel was studied. The in vivo wound-healing activity and antibacterial efficacy of Na CMC hydrogel loaded with PEG-coated AgNPs in comparison to the commercially available silver sulfadiazine cream (Dermazin ® ) were evaluated. Superior antibacterial activity and wound-healing capability, with normal skin appearance and hair growth, were demonstrated for the hydrogel formulations, as compared to the silver

  5. A plan to reduce volatile organic compound emissions from consumer products in Canada (excluding windshield washer fluid and surface coatings) : final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    This report highlights the recommendations made by the Canadian Council of Ministers of the Environment for the development of a guideline to provide a means by which to reduce (VOC) emissions from consumer products (excluding windshield washer fluid and surface coatings) in Canada. VOCs and nitrogen oxides react photochemically in the presence of sunlight to create ground-level ozone, a primary component of urban smog which has a detrimental effect on human health, agricultural crops and building materials. In recent years, most urban areas of Canada have shown an annual increase in the maximum acceptable air quality levels for ground level ozone. Reducing emissions of volatile organic compounds (VOCs) from consumer products was first suggested in 1990 by the Canadian Council of Ministers of the Environment in phase one of their program entitled the 'Management plan for nitrogen oxides and volatile organic compounds'. Phase 2 of the program was implemented in 1997 to harmonize the emissions reduction program with the United States Environmental Protection Agency regulations. The Canadian Environmental Protection Agency (CEPA) recommended the following control options: (1) a CEPA guideline should be developed which states the maximum VOC and high-volatility organic compound (HVOC) content in Canadian consumer products including hair care products, herbicides, insecticides, air fresheners, deodorants, fungicides, surface cleaners, fragrance products, anti-microbial agents, laundry products and automotive detailing products. These limits should be identical to those found in the 1998 U.S. Final Rule for Consumer Products, (2) the CEPA guideline should require that records specifying VOC content in weight-per cent be maintained for a period of three years, (3) the CEPA guideline should include a declaration procedure for Canadian importers and manufacturers of consumer products to report to Environment Canada regarding the VOC content of their products, and

  6. Cutting concrete with abrasion jet

    International Nuclear Information System (INIS)

    Yie, G.G.

    1982-01-01

    Fluidyne Corporation has developed a unique process and apparatus that allow selected abrasives to be introduced into high-speed waterjet to produce abrasive-entrained waterjet that has high material-cutting capabilities, which is termed by Fluidyne as the Abrasion Jet. Such Abrasion Jet has demonstrated capability in cutting hard rock and concrete at a modest pressure of less than 1360 bars (20,000 psi) and a power input of less than 45 kW (60 horsepower). Abrasion Jet cutting of concrete is characterized by its high rate of cutting, flexible operation, good cut quality, and relatively low costs. This paper presents a general description of this technology together with discussions of recent test results and how it could be applied to nuclear decontamination and decommissioning work. 8 references

  7. Exploring Cu{sub 2}O/Cu cermet as a partially inert anode to produce aluminum in a sustainable way

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Li-Chao [School of Mechanical Engineering, Huaihai Institute of Technology and Jiangsu Province R and D Institute of Marine Resources, Lianyungang 222005 (China); School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xie, Ning, E-mail: xiening@hit.edu.cn [School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shao, Wen-Zhu, E-mail: wzshao@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhen, Liang [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ivanov, V.V. [Physical Chemistry Department, Siberian Federal University, Krasnoyarsk 660041 (Russian Federation)

    2014-10-15

    Highlights: • Cu{sub 2}O/Cu cermet was used as a candidate partially inert anode material to produce aluminum alloys. • The thermal corrosion behavior of Cu{sub 2}O/Cu was investigated in molten salt at 960 °C. • The corrosion rate is largely governed by the geometrical structures of Cu in the prepared samples. • The corrosion rate increases with decreasing sizes and increasing filling contents of Cu phase. • The corrosion rate was 1.8–9 cm/y and the Cu contents is less than 6.2 wt.% in the produced aluminum. - Abstract: As an energy-intensive process, aluminum production by the Hall–Héroult method accounts for significant emissions of CO{sub 2} and some toxic greenhouse gases. The utilization of an inert anode in place of a carbon anode was considered as a revolutionary technique to solve most of the current environmental problems resulting from the Hall–Héroult process. However, the critical property requirements of the inert anode materials significantly limit the application of this technology. In light of the higher demand for aluminum alloys than for pure aluminum, a partially inert anode was designed to produce aluminum alloys in a more sustainable way. Here, Cu{sub 2}O/Cu cermet was chosen as the material of interest. The thermal corrosion behavior of Cu{sub 2}O/Cu was investigated in Na{sub 3}AlF{sub 6}–CaF{sub 2}–Al{sub 2}O{sub 3} electrolyte at 960 °C to elucidate the corrosion mechanisms of this type of partially inert anode for the production of aluminum or aluminum alloys. Furthermore, the effects of the geometrical structure of the Cu phase on the thermal corrosion behavior of Cu{sub 2}O/Cu cermet in the electrolyte were investigated as well. The thermal corrosion rate was evaluated by the weight loss method and the results show that the samples prepared with branch-like Cu have higher thermal corrosion rate than those prepared with spherical Cu, and the corrosion rate increases with decreasing size and increasing filling

  8. Preferences of cut flowers consumers

    Directory of Open Access Journals (Sweden)

    Sylwia Kierczyńska

    2010-01-01

    Full Text Available The results of interviews suggest that majority of the cut flowers’ consumers has favourite kind of flower, among which most frequently pointed one was the rose. More than half of the interviewed favour the uniform colour of cut flowers and red colour was the most favourite one. The subtle smell of flowers was the most preferable one but the intensive fragrance was favoured for more consumers than odourless flowers. The data from selected florists’ confirm the information from interviews – in spite of the occasion, roses were the most demanded cut flowers.

  9. Laser cutting of Kevlar laminates

    Energy Technology Data Exchange (ETDEWEB)

    VanCleave, R.A.

    1977-09-01

    An investigation has been conducted of the use of laser energy for cutting contours, diameters, and holes in flat and shaped Kevlar 49 fiber-reinforced epoxy laminates as an alternate to conventional machining. The investigation has shown that flat laminates 6.35 mm thick may be cut without backup by using a high-powered (1000-watt) continuous wave CO/sub 2/ laser at high feedrates (33.87 mm per second). The cut produced was free of the burrs and delaminations resulting from conventional machining methods without intimate contact backup. In addition, the process cycle time was greatly reduced.

  10. Regge cuts in inclusive reactions

    International Nuclear Information System (INIS)

    Paige, F.E.; Trueman, T.L.

    1975-01-01

    The contribution of Regge cuts to single-particle inclusive processes is analyzed using the techniques of Gribov. The dependence of these contributions on the polarization state of the target is emphasized. A general formula is obtained and certain contributions to it are calculated. It is not possible, however, to reduce this to a simple, powerful formula expressing the total cut contribution in terms of other measurable quantities, as can be done for the cut contribution to the total cross section. The reasons for this are discussed in detail. The single-particle intermediate states, analogous to the absorption model for elastic scattering, are explicitly calculated as an illustration

  11. Application of Multi-Species Microbial Bioassay to Assess the Effects of Engineered Nanoparticles in the Aquatic Environment: Potential of a Luminous Microbial Array for Toxicity Risk Assessment (LumiMARA on Testing for Surface-Coated Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    YounJung Jung

    2015-07-01

    Full Text Available Four different manufactured surface-coated silver nanoparticles (AgNPs with coating of citrate, tannic acid, polyethylene glycol, and branched polyethylenimine were used in this study. The toxicity of surface-coated AgNPs was evaluated by a luminous microbial array for toxicity risk assessment (LumiMARA using multi-species of luminescent bacteria. The salt stability of four different AgNPs was measured by UV absorbance at 400 nm wavelength, and different surface-charged AgNPs in combination with bacteria were observed using scanning electron microscopy (SEM. Both branched polyethylenimine (BPEI-AgNPs and polyethylene glycol (PEG-AgNPs were shown to be stable with 2% NaCl (non-aggregation, whereas both citrate (Cit-AgNPs and tannic acid (Tan-AgNPs rapidly aggregated in 2% NaCl solution. The values of the 50% effective concentration (EC50 for BPEI-AgNPs in marine bacteria strains (1.57 to 5.19 mg/L were lower than those for the other surface-coated AgNPs (i.e., Cit-AgNPs, Tan-AgNPs, and PEG-AgNPs. It appears that the toxicity of AgNPs could be activated by the interaction of positively charged AgNPs with the negatively charged bacterial cell wall from the results of LumiMARA. LumiMARA for toxicity screening has advantageous compared to a single-species bioassay and is applicable for environmental samples as displaying ranges of assessment results.

  12. Effect of Fe on the phases and microstructure of TiC-Fe cermets by combustion synthesis/quasi-isostatic pressing

    International Nuclear Information System (INIS)

    Zhang Weifang; Zhang Xinghong; Wang Jianli; Hong Changqing

    2004-01-01

    Fully dense TiC-Fe cermets (x = 10, 20, 30, and 40 wt.%) were produced from Ti-C-Fe powder mixtures by combustion synthesis with quasi-isostatic pressing. The effect of Fe content on combustion temperature, combustion wave velocity, and final product density was investigated. The final product was characterized by XRD, SEM, and TEM. The combustion temperature and wave velocity decreased with increasing Fe content. Product density increased with increasing Fe content (96% at 30 wt.%). X-ray diffraction and transmission electron microscopy (TEM) revealed the final product to contain TiC, Fe phases, lath martensite, and Fe 2 Ti. The TiC particle size decreased with increasing Fe content. In addition, a low density of dislocations was observed in both the TiC particles and Fe binder, indicative of annealing and recrystallization, respectively

  13. High Temperature Oxidation of Nickel-based Cermet Coatings Composed of Al2O3 and TiO2 Nanosized Particles

    Science.gov (United States)

    Farrokhzad, M. A.; Khan, T. I.

    2014-09-01

    New technological challenges in oil production require materials that can resist high temperature oxidation. In-Situ Combustion (ISC) oil production technique is a new method that uses injection of air and ignition techniques to reduce the viscosity of bitumen in a reservoir and as a result crude bitumen can be produced and extracted from the reservoir. During the in-situ combustion process, production pipes and other mechanical components can be exposed to air-like gaseous environments at extreme temperatures as high as 700 °C. To protect or reduce the surface degradation of pipes and mechanical components used in in-situ combustion, the use of nickel-based ceramic-metallic (cermet) coating produced by co-electrodeposition of nanosized Al2O3 and TiO2 have been suggested and earlier research on these coatings have shown promising oxidation resistance against atmospheric oxygen and combustion gases at elevated temperatures. Co-electrodeposition of nickel-based cermet coatings is a low-cost method that has the benefit of allowing both internal and external surfaces of pipes and components to be coated during a single electroplating process. Research has shown that the volume fraction of dispersed nanosized Al2O3 and TiO2 particles in the nickel matrix which affects the oxidation resistance of the coating can be controlled by the concentration of these particles in the electrolyte solution, as well as the applied current density during electrodeposition. This paper investigates the high temperature oxidation behaviour of novel nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in a nickel matrix and produced by coelectrodeposition technique as a function of the concentration of these particles in the electrolyte solution and applied current density. For this purpose, high temperature oxidation tests were conducted in dry air for 96 hours at 700 °C to obtain mass changes (per unit of area) at specific time

  14. Influence of the shielding effect on the formation of a micro-texture on the cermet with nanosecond pulsed laser ablation.

    Science.gov (United States)

    Yuan, Jiandong; Liang, Liang; Jiang, Lelun; Liu, Xin

    2018-04-01

    The degree of laser pulse overlapping in a laser scanning path has a significant impact on the ablation regime in the laser machining of a micro-texture. In this Letter, a nanosecond pulsed laser is used to prepare the micro-scaled groove on WC-8Co cermet under different scanning speeds. It is observed that as the scanning speed increases, the ablated trace morphology in the first scanning pass transits from a succession of intermittent deep dimples to the consecutive overlapped shallow pits. The test result also indicates that ablated trace morphology with respect to the low scanning speed stems from a plume shielding effect. Moreover, the ablation regime considering the shielding effect in micro-groove formation process is clarified. The critical scanning speed that can circumvent the shielding effect is also summarized with respect to different laser powers.

  15. Inactivation of Vegetative Cells, but Not Spores, of Bacillus anthracis, B. cereus, and B. subtilis on Stainless Steel Surfaces Coated with an Antimicrobial Silver- and Zinc-Containing Zeolite Formulation

    Science.gov (United States)

    Galeano, Belinda; Korff, Emily; Nicholson, Wayne L.

    2003-01-01

    Stainless steel surfaces coated with paints containing a silver- and zinc-containing zeolite (AgION antimicrobial) were assayed in comparison to uncoated stainless steel for antimicrobial activity against vegetative cells and spores of three Bacillus species, namely, B. anthracis Sterne, B. cereus T, and B. subtilis 168. Under the test conditions (25°C and 80% relative humidity), the zeolite coating produced approximately 3 log10 inactivation of vegetative cells within a 5- to 24-h period, but viability of spores of the three species was not significantly affected. PMID:12839825

  16. In vitro and in vivo evaluation of biologically synthesized silver nanoparticles for topical applications: effect of surface coating and loading into hydrogels

    Directory of Open Access Journals (Sweden)

    Mekkawy AI

    2017-01-01

    -AgNPs dispersions using several gelling agents (sodium carboxymethyl cellulose [Na CMC], sodium alginate, hydroxypropylmethyl cellulose, Pluronic F-127, and chitosan. The prepared formulations were evaluated for their viscosity, spreadability, in vitro drug release, and antibacterial activity, and the combined effect of the type of surface coating and the polymers utilized to form the gel was studied. The in vivo wound-healing activity and antibacterial efficacy of Na CMC hydrogel loaded with PEG-coated AgNPs in comparison to the commercially available silver sulfadiazine cream (Dermazin® were evaluated. Superior antibacterial activity and wound-healing capability, with normal skin appearance and hair growth, were demonstrated for the hydrogel formulations, as compared to the silver sulfadiazine cream. Histological examination of the treated skin was performed using light microscopy, whereas the location of AgNPs in the skin epidermal layers was visualized using transmission electron microscopy. Keywords: silver nanoparticles, green synthesis, coating agents, hydrogel, wound healing, antibacterial activity

  17. An Investigation on the Wear and Corrosion Behavior of HVOF-Sprayed WC-12Co-Al2O3 Cermet Coating

    Science.gov (United States)

    Chakradhar, R. P. S.; Prasad, G.; Venkateswarlu, K.; Srivastava, Meenu

    2018-03-01

    The aim of the present study is to develop thermally sprayable WC-12Co and WC-12Co- xAl2O3 ( x = 10 and 15 wt.%) cermet coatings on steel substrate (SS 304) by high-velocity oxy fuel (HVOF) method. Influence of Al2O3 addition on the wear and corrosion behavior of WC-12Co coating has been studied. The microstructure and chemical composition of the coatings were analyzed using field emission scanning electron microscope (FESEM), and phase identification was carried out using x-ray diffraction (XRD) studies. The morphology of the coating appears as coarse granular structure. The XRD studies revealed the presence of hexagonal WC phase along with η-Co6W6C phase. It has been observed from the microhardness measurements, that the values gradually increase from 950 to 1300 HK with the addition of Al2O3 from 0 to 15 wt.%. The wear rate of WC-12Co-15Al2O3 (3.19 × 10-6 mm3/Nm) and WC-12Co-10Al2O3 (5.26 × 10-6 mm3/Nm) coatings was seen to be one order of magnitude lower than that of WC-12Co (2.9 × 10-5 mm3/Nm) coating. The polarization studies revealed that WC-12Co-15Al2O3 cermet coating showed superior corrosion protection than that of WC-12Co-10Al2O3 and WC-12Co coatings. This has been attributed to the gradual decrease in the porosity levels with an increase in Al2O3 content which is supported by morphology studies. The microhardness and wear behavior of WC-12Co-Al2O3 coatings are equivalent to those of hard chrome suggesting the possibility of its replacement.

  18. Preferences of cut flowers consumers

    OpenAIRE

    Sylwia Kierczyńska

    2010-01-01

    The results of interviews suggest that majority of the cut flowers’ consumers has favourite kind of flower, among which most frequently pointed one was the rose. More than half of the interviewed favour the uniform colour of cut flowers and red colour was the most favourite one. The subtle smell of flowers was the most preferable one but the intensive fragrance was favoured for more consumers than odourless flowers. The data from selected florists’ confirm the information from interviews – in...

  19. Interactive cutting path analysis programs

    Science.gov (United States)

    Weiner, J. M.; Williams, D. S.; Colley, S. R.

    1975-01-01

    The operation of numerically controlled machine tools is interactively simulated. Four programs were developed to graphically display the cutting paths for a Monarch lathe, Cintimatic mill, Strippit sheet metal punch, and the wiring path for a Standard wire wrap machine. These programs are run on a IMLAC PDS-ID graphic display system under the DOS-3 disk operating system. The cutting path analysis programs accept input via both paper tape and disk file.

  20. Economic technology of laser cutting

    Science.gov (United States)

    Fedin, Alexander V.; Shilov, Igor V.; Vassiliev, Vladimir V.; Malov, Dmitri V.; Peskov, Vladimir N.

    2000-02-01

    The laser cutting of color metals and alloys by a thickness more than 2 mm has significant difficulties due to high reflective ability and large thermal conduction. We made it possible to raise energy efficiency and quality of laser cutting by using a laser processing system (LPS) consisting both of the YAG:Nd laser with passive Q-switching on base of LiF:F2- crystals and the CO2 laser. A distinctive feature of the LPS is that the radiation of different lasers incorporated in a coaxial beam has simultaneously high level of peak power (more than 400 kW in a TEM00 mode) and significant level of average power (up to 800 W in a TEM01 mode of the CO2 laser). The application of combined radiation for cutting of an aluminum alloy of D16 type made it possible to decrease the cutting energy threshold in 1.7 times, to increase depth of treatment from 2 up to 4 mm, and velocity from 0.015 up to 0.7 m/min, and also to eliminate application of absorptive coatings. At cutting of steels the velocity of treatment was doubled, and also an oxygen flow was eliminated from the technological process and replaced by the air. The obtained raise of energy efficiency and quality of cutting is explained by an essential size reducing of a formed penetration channel and by the shifting of a thermal cutting mode from melting to evaporation. The evaluation of interaction efficiency of a combined radiation was produced on the basis of non-stationary thermal-hydrodynamic model of a heating source moving as in the cutting direction, and also into the depth of material.

  1. Twice cutting method reduces tibial cutting error in unicompartmental knee arthroplasty.

    Science.gov (United States)

    Inui, Hiroshi; Taketomi, Shuji; Yamagami, Ryota; Sanada, Takaki; Tanaka, Sakae

    2016-01-01

    Bone cutting error can be one of the causes of malalignment in unicompartmental knee arthroplasty (UKA). The amount of cutting error in total knee arthroplasty has been reported. However, none have investigated cutting error in UKA. The purpose of this study was to reveal the amount of cutting error in UKA when open cutting guide was used and clarify whether cutting the tibia horizontally twice using the same cutting guide reduced the cutting errors in UKA. We measured the alignment of the tibial cutting guides, the first-cut cutting surfaces and the second cut cutting surfaces using the navigation system in 50 UKAs. Cutting error was defined as the angular difference between the cutting guide and cutting surface. The mean absolute first-cut cutting error was 1.9° (1.1° varus) in the coronal plane and 1.1° (0.6° anterior slope) in the sagittal plane, whereas the mean absolute second-cut cutting error was 1.1° (0.6° varus) in the coronal plane and 1.1° (0.4° anterior slope) in the sagittal plane. Cutting the tibia horizontally twice reduced the cutting errors in the coronal plane significantly (Pcutting the tibia horizontally twice using the same cutting guide reduced cutting error in the coronal plane. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Extensions of cutting problems: setups

    Directory of Open Access Journals (Sweden)

    Sebastian Henn

    2013-08-01

    Full Text Available Even though the body of literature in the area of cutting and packing is growing rapidly, research seems to focus on standard problems in the first place, while practical aspects are less frequently dealt with. This is particularly true for setup processes which arise in industrial cutting processes whenever a new cutting pattern is started (i.e. a pattern is different from its predecessor and the cutting equipment has to be prepared in order to meet the technological requirements of the new pattern. Setups involve the consumption of resources and the loss of production time capacity. Therefore, consequences of this kind must explicitly be taken into account for the planning and control of industrial cutting processes. This results in extensions to traditional models which will be reviewed here. We show how setups can be represented in such models, and we report on the algorithms which have been suggested for the determination of solutions of the respective models. We discuss the value of these approaches and finally point out potential directions of future research.

  3. Cutting inlays with a laser

    Science.gov (United States)

    Swaczyna, Irena; Grabczewski, Zbigniew

    1995-03-01

    To cut inlay from a stack of glued veneer a CO2 HEBAR-1A laser was used. For setting optimal working parameters of the set used in industrial production of inlay the following elements were defined: the shape and dimensions of the cutting fissure, the dependence between the width of the cutting fissure and the speed with which the laser beam moves and the total thickness of the stack of veneer sheets, the application of the laser for cutting various patterns. Computer aided designing and computer steering of the laser beam enables fast and precise production of large numbers of inlay elements not only from wood but also from other materials like glass, stone, metal, etc. Taking into consideration the high running cost of such a laser set and its very big production only few factories or even one factory in the given area could produce inlay ready for gluing. Further investigation should be carried out on this field particularly considering the lowering of costs not only in inlay production but generally where cutting of wood is concerned.

  4. Model-supported interpretation of the electrochemical characteristics of solid oxide fuel cells with Ni/YSZ cermet anodes; Modellgestuetzte Interpretation der elektrochemischen Charakteristik von Festoxid-Brennstoffzellen mit Ni/YSZ-Cermetanoden

    Energy Technology Data Exchange (ETDEWEB)

    Gewies, Stefan

    2009-01-29

    This work presents the development, validation and application of a multiscale model for the detailed description of a solid oxide fuel cell (SOFC) with a Ni/YSZ (nickel/yttria-stabilized zirconia) cermet anode. The aim of the study is the identification of the physico-chemical loss processes, as seen in impedance spectra and polarization curves. The model consists of an elementary kinetic description of the electrochemistry including the development of an electrical double layer at the electrode/electrolyte interface of the cermet anode, a homogenized description of charge and gas-phase transport in the electrodes as well as a macroscopic description of convective and diffusive mass transport in the gas phase above the electrodes. For the rst time this study allows for a complete description of the impedance spectra of a diffusively fuel-supplied cermet anode. By comparing simulations with experiments on symmetrical cells (University of Karlsruhe) three dominant loss processes could be identified. The model was extended to account for the description of segmented SOFCs. In correspondence with experimental data (German Aerospace Center) the simulations show strong gradients in current densities and gas concentrations. (orig.)

  5. The Cutting Process, Chips and Cutting Forces in Machining CFRP

    DEFF Research Database (Denmark)

    Koplev, A.; Lystrup, Aage; Vorm, T.

    1983-01-01

    The cutting of unidirectional CFRP, perpendicular as well as parallel to the fibre orientation, is examined. Shaping experiments, ‘quick-stop’ experiments, and a new chip preparation technique are used for the investigation. The formation of the chips, and the quality of the machined surface...

  6. Equilibrium Analysis in Cake Cutting

    DEFF Research Database (Denmark)

    Branzei, Simina; Miltersen, Peter Bro

    2013-01-01

    Cake cutting is a fundamental model in fair division; it represents the problem of fairly allocating a heterogeneous divisible good among agents with different preferences. The central criteria of fairness are proportionality and envy-freeness, and many of the existing protocols are designed...... of the simplest and most elegant continuous algorithms -- the Dubins-Spanier procedure, which guarantees a proportional allocation of the cake -- and study its equilibria when the agents use simple threshold strategies. We show that given a cake cutting instance with strictly positive value density functions...

  7. Cutting temperature measurement and material machinability

    Directory of Open Access Journals (Sweden)

    Nedić Bogdan P.

    2014-01-01

    Full Text Available Cutting temperature is very important parameter of cutting process. Around 90% of heat generated during cutting process is then away by sawdust, and the rest is transferred to the tool and workpiece. In this research cutting temperature was measured with artificial thermocouples and question of investigation of metal machinability from aspect of cutting temperature was analyzed. For investigation of material machinability during turning artificial thermocouple was placed just below the cutting top of insert, and for drilling thermocouples were placed through screw holes on the face surface. In this way was obtained simple, reliable, economic and accurate method for investigation of cutting machinability.

  8. Clustering by Minimum Cut Hyperplanes.

    Science.gov (United States)

    Hofmeyr, David P

    2017-08-01

    Minimum normalised graph cuts are highly effective ways of partitioning unlabeled data, having been made popular by the success of spectral clustering. This work presents a novel method for learning hyperplane separators which minimise this graph cut objective, when data are embedded in Euclidean space. The optimisation problem associated with the proposed method can be formulated as a sequence of univariate subproblems, in which the optimal hyperplane orthogonal to a given vector is determined. These subproblems can be solved in log-linear time, by exploiting the trivial factorisation of the exponential function. Experimentation suggests that the empirical runtime of the overall algorithm is also log-linear in the number of data. Asymptotic properties of the minimum cut hyperplane, both for a finite sample, and for an increasing sample assumed to arise from an underlying probability distribution are discussed. In the finite sample case the minimum cut hyperplane converges to the maximum margin hyperplane as the scaling parameter is reduced to zero. Applying the proposed methodology, both for fixed scaling, and the large margin asymptotes, is shown to produce high quality clustering models in comparison with state-of-the-art clustering algorithms in experiments using a large collection of benchmark datasets.

  9. How Can I Stop Cutting?

    Science.gov (United States)

    ... some relaxing yoga exercises Things to Help You Express the Pain and Deep Emotion Some people cut because the emotions that they ... may be hard for them to recognize these emotions for what they are — like anger, ... songs or poetry to express what you're feeling listen to music that ...

  10. Brazilian science faces swingeing cuts

    Science.gov (United States)

    Ivanissevich, Alicia

    2017-05-01

    A number of “big-science” projects in Brazil could be hit if the government pushes through a 44% cut to the R5bn (£1.28bn) budget of the Ministry of Science, Technology, Innovations and Communications (MCTIC).

  11. The Cutting-Edge Challenge

    Science.gov (United States)

    Share, Joani

    2005-01-01

    In a time of educational budget cuts, the arts seem to take the major brunt of the financial ax. Fine arts programs are often pitted against one another for survival. The music industry and supporting corporations, such as American Express, campaign to have instruments donated or purchased to keep educational programs alive. The visual arts do not…

  12. Why I like power cuts...

    CERN Multimedia

    Computer Security Team

    2012-01-01

    Accidental power cuts - a permanent nuisance when running accelerators or computing services, since it takes a lot of time to recover from them. While I feel very sorry for those who are under pressure to get their service running again and deeply regret the loss of down-time and availability, I must admit that I like power cuts: power cuts make computers reboot! And rebooting computers at CERN means all the pending software patches are automatically applied.   But don’t think I am egotistic enough to endorse power cuts. Not necessarily! I am already happy if you regularly patch your computer(s) yourself, where regularly means at least once a month: · If you run a centrally or locally managed Windows computer, give that small orange blinking “CMF” icon in the taskbar a chance in the evening to apply all the pending patches. Also, let it initiate a reboot at the end! · If you have a personal computer with your own Windows operating system, ...

  13. Geometry of Cuts and Metrics

    NARCIS (Netherlands)

    M. Deza; M. Laurent (Monique)

    1997-01-01

    htmlabstractCuts and metrics are well-known objects that arise - independently, but with many deep and fascinating connections - in diverse fields: in graph theory, combinatorial optimization, geometry of numbers, combinatorial matrix theory, statistical physics, VLSI design etc. This book offers a

  14. Cutting and Preserving Whole Turkey

    OpenAIRE

    Brennand, Charlotte P.

    1995-01-01

    There are more uses for a turkey than roasting it whole for holiday occasions. The least expensive way to have turkey pieces, especially if the turkey is purchased on sale, is to cut it up yourself. The following is to serve as a butchering and processing guide.

  15. Research on the Effect of Cutting Parameters on Chip Formation and Cutting Force in Elliptical Vibration Cutting Process

    Science.gov (United States)

    Lin, Jieqiong; Guan, Liang; Lu, Mingming; Han, Jinguo; Feng, Da

    2017-12-01

    Elliptical vibration cutting (EVC) has been widely concerned since it was proposed, and its unique characteristics such as friction reversal and intermittent cutting can effectively extend the tool life, improve the machined surface roughness and so on. The objective of this paper was to predict the behavior of cutting force. A method of predicting the behavior of cutting force based on the chip thickness under various cutting conditions is proposed. Based on the established tool motion model, the chip model was founded. By numerical simulation, the effects of cutting parameters on cutting force under various cutting conditions were studied. The results show that the chip thickness can be used to predict the behavior of cutting force.

  16. Wedge cutting of mild steel by CO 2 laser and cut-quality assessment in relation to normal cutting

    Science.gov (United States)

    Yilbas, B. S.; Karatas, C.; Uslan, I.; Keles, O.; Usta, Y.; Yilbas, Z.; Ahsan, M.

    2008-10-01

    In some applications, laser cutting of wedge surfaces cannot be avoided in sheet metal processing and the quality of the end product defines the applicability of the laser-cutting process in such situations. In the present study, CO 2 laser cutting of the wedge surfaces as well as normal surfaces (normal to laser beam axis) is considered and the end product quality is assessed using the international standards for thermal cutting. The cut surfaces are examined by the optical microscopy and geometric features of the cut edges such as out of flatness and dross height are measured from the micrographs. A neural network is introduced to classify the striation patterns of the cut surfaces. It is found that the dross height and out of flatness are influenced significantly by the laser output power, particularly for wedge-cutting situation. Moreover, the cut quality improves at certain value of the laser power intensity.

  17. Effect of H{sub 2}S on the thermodynamic stability and electrochemical performance of Ni cermet-type of anodes for solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Venkateswara Rao, M.

    2006-11-15

    For SOFCs to be main means of power generation, they should be able to exploit wide variety of fuels. Among Ni-cermets, Ni-YSZ is the state-of-the-art materials for SOFC-anode which is the fuel electrode. But sulphur impurity present in different gaseous fuels (e.g Biogas), depending on its concentration, is highly poisonous to the stability and electrochemical performance of the Ni catalyst in the cermet anodes. Thus in this study the microstructural stability of Ni-YSZ, Ni-CGO and Ni-LSGM cermets in H{sub 2}S-containing hydrogen gas is studied in the intermediate temperature range of SOFC operation. Thermodynamic modelling of Ni-S-O-H quaternary system was performed for the calculation of thermodynamic stability and sulphur-tolerance limit of Ni in the gaseous atmosphere made up of H, O and S. The effect of presence H{sub 2}S in fuel gas, in the concentrations well below the thermodynamic tolerance limit, on the electrochemical performance of the anodes is studied by using model Ni-patterned electrodes on YSZ and LSGM. Thermodynamic modelling of the Ni-S-O-H quaternary was performed by employing CALPHAD methodology. The modelling of Ni-S binary phase diagram was performed by using sublattice models for the non-stoichiometric phases. The optimised binaries of Ni-O, and Ni-H were taken from the literature. The Ni-O-S and Ni-O-H ternaries were extrapolated from the lower order binaries. In Ni-O-S ternary, NiSO{sub 4} is the only ternary compound present. The ternary compounds, Ni(OH){sub 2} and NiOOH in the Ni-O-H ternary were considered as stoichiometric line compounds. The model parameters of the ternary compounds were optimised using the experimental data. The Ni-S-O-H quaternary was calculated by extrapolation method as employed in the CALPHAD methodology. Inorder to understand the H{sub 2}-oxidation mechanism and the role played by the electrolyte in the reaction mechanism, symmetrical cells of Ni-patterned YSZ single crystals with different crystallographic

  18. Analysis of changes in paper cutting forces during the cutting cycle in single-knife guillotine

    OpenAIRE

    Rusin, Agnieszka; Petriaszwili, Georgij

    2013-01-01

    Paper presents the results of changes in the three components of cutting forces of paper stacks cutting during the cutting cycle in single-knife guillotine. The changes of the three components of cutting force at different stages of cutting cycle were analyzed.

  19. Cutting

    Science.gov (United States)

    ... depression, bipolar disorder , eating disorders, obsessive thinking, or compulsive behaviors. It can also be a sign of mental ... can be habit forming. It can become a compulsive behavior — meaning that the more a person does it, ...

  20. Enhancing Properties and Performance of Cellulose Acetate/Polyethylene Glycol (CA/PEG Membrane with the addition of Titanium Dioxide (TiO2 by Using Surface Coating Method

    Directory of Open Access Journals (Sweden)

    Nurkhamidah Siti

    2018-01-01

    Full Text Available In this study, cellulose acetate/polyethylene glycol (CA/PEG membrane with composition 80/20 was prepared by phase inversion method. Titanium dioxide with different number has been added by using surface coating. Hydrophilicity, morphology, flux permeate and salt rejection of membranes has been studied. The hydrophilicity is determined by Fourier-Transformed Infra-Red (FTIR spectra and contact angle analysis. Surface and fractured morphology are identified by using Scanning Electron Microscopy (SEM. The experiment results show that hydrophilicity of CA/PEG membrane increases with the addition and the increasing of TiO2 contents. However, with further increasing of TiO2, hydrophilicity of CPT membrane decreases. The optimum membrane is CA/PEG/TiO2 80/20/1,25 g/L solvent (CPT 3 with flux permeate of 111,82 L.m-2h-1 and salt rejection of 48,30%.

  1. Water-Cut Sensor System

    KAUST Repository

    Karimi, Muhammad Akram

    2018-01-11

    Provided in some embodiments is a method of manufacturing a pipe conformable water-cut sensors system. Provided in some embodiments is method for manufacturing a water-cut sensor system that includes providing a helical T-resonator, a helical ground conductor, and a separator at an exterior of a cylindrical pipe. The helical T-resonator including a feed line, and a helical open shunt stub conductively coupled to the feed line. The helical ground conductor including a helical ground plane opposite the helical open shunt stub and a ground ring conductively coupled to the helical ground plane. The feed line overlapping at least a portion of the ground ring, and the separator disposed between the feed line and the portion of the ground ring overlapped by the feed line to electrically isolate the helical T-resonator from the helical ground conductor.

  2. Performance of Ni/ScSZ cermet anode modified by coating with Gd0.2Ce0.8O2 for a SOFC

    International Nuclear Information System (INIS)

    Huang Bo; Ye, X.F.; Wang, S.R.; Nie, H.W.; Liu, R.Z.; Wen, T.L.

    2007-01-01

    A Ni/scandia-stabilized zirconia (ScSZ) cermet anode was modified by coating with nano-sized gadolinium-doped ceria (GDC, Gd 0.2 Ce 0.8 O 2 ) within the pores of the anode for a solid oxide fuel cell (SOFC). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed in the anode characterizations. Open circuit voltages (OCVs) increased from 1.027 to 1.078 V, and the maximum power densities increased from 238 to 825 mW/cm 2 , as the operating temperature of a SOFC with 2.0 wt.%GDC-coated Ni/ScSZ anode was increased from 700 to 850 deg. C in humidified hydrogen. The coating of nano-sized Gd 0.2 Ce 0.8 O 2 particle within the pores of the porous Ni/ScSZ anode significantly improved the performance of anode supported cell. Electrochemical impedance spectra (EIS) illustrated that the cell with Ni/ScSZ anode exhibited far greater impedances than the cell with 2.0 wt.%GDC-coated Ni/ScSZ anode. Consequently, 2.0 wt.%GDC-coated Ni/ScSZ anode could be used as a novel anode material for a SOFC due to better electrochemical performance

  3. Tribological properties of B{sub 4}C-TiB{sub 2}-TiC-Ni cermet coating produced by HVOF

    Energy Technology Data Exchange (ETDEWEB)

    Rafiei, Mahdi [Islamic Azad Univ., Najafabad (Iran, Islamic Republic of). Dept. of Materials Engineering; Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Depr. of Materials Engineering; Shamanian, Morteza; Salehi, Mehdi [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of). Depr. of Materials Engineering; Mostaan, Hossein [Arak Univ., Arak (Iran, Islamic Republic of). Dept. of Materials and Metallurgical Engineering

    2017-08-15

    In this study, B{sub 4}C-TiB{sub 2}-TiC-Ni coating was sprayed on the surface of 4130 steel by high velocity oxy-fuel torch. The tribological behavior of samples was studied by ball on disk wear testing. Structural evolution of the coating was analyzed by X-ray diffractometry. The microstructure of the coating, wear track and Al{sub 2}O{sub 3} ball was investigated by scanning electron microscopy, field emission scanning electron microscopy and optical microscopy. Elemental analysis of the wear track was done by energy dispersive X-ray spectroscopy. It was found that a cermet coating containing B{sub 4}C, TiB{sub 2}, TiC and Ni phases with good bonding to the 4130 steel substrate with no sign of any cracking or pores was formed. The wear mechanism of the composite coating was delamination. The friction coefficient of samples was decreased with increasing load because of higher frictional heat and creation of more oxide islands.

  4. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical report, January 14, 1997--August 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Schorr, B.S.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1997-08-31

    Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. Bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. Also, to deposit model Ni-Al{sub 2}O{sub 3} coatings, an electrodeposition technique was developed and coatings with various volume fractions (0-35%) of Al{sub 2}O{sub 3} were produced. The powder and electrodeposition processing of Ni-Al{sub 2}O{sub 3} Composites provide the ability to produce two phase microstructure without changing the microstructure of the matrix material. Therefore, the effect of hard second phase particles size and volume fraction on erosion resistance could be analyzed.

  5. Method of cutting radioactivated metal structures

    International Nuclear Information System (INIS)

    Takimoto, Yoshinori; Sakota, Kotaro; Hamamoto, Noboru; Harada, Keizo.

    1985-01-01

    Purpose: To improve the cutting performance to a level as comparable with that in air, as well as prevent the scattering of the radioactive materials upon cutting to the level as that in water cutting. Method: After igniting a gas cutting torch automatically, water spray by the local water sprayer is started by the actuation of a submerged pump, while a gas cutting manipulator is operated to cut the nuclear reactor pressure vessel. In this way, cutting exhaust gases resulted from the gas cutting torch are water-washed by the spray from the local water sprayer and falls within the nuclear rector pressure vessel in the form of water streams or droplets along the inner wall surface of the pressure vessel. Further, water is fed again to the local water sprayer by the submerged pump. (Kawakami, Y.)

  6. European labs fight back against cuts

    CERN Multimedia

    König, R

    1997-01-01

    Germany's 1997 budget contains cuts amounting to 3.7% in funding of domestic research programs and in contributions to international labs. Contributions will be cut to the European Space Agency, the European Synchrotron facility and CERN.

  7. Effects of heat on cut mark characteristics.

    OpenAIRE

    Waltenberger, L.; Schutkowski, Holger

    2017-01-01

    Cut marks on bones provide crucial information about tools used and their mode of application, both in archaeological and forensic contexts. Despite a substantial amount of research on cut mark analysis and the influence of fire on bones (shrinkage, fracture pattern, recrystallisation), there is still a lack of knowledge in cut mark analysis on burnt remains. This study provides information about heat alteration of cut marks and whether consistent features can be observed that allow direct in...

  8. The size effect in metal cutting

    Indian Academy of Sciences (India)

    and when the size of the material removed decreases, the probability of encountering a stress-reducing defect decreases. Since the shear stress and strain in metal cutting is unusually high, discontinuous microcracks usually form on the metal-cutting shear plane. If the material being cut is very brittle, or the compressive ...

  9. Optical Cutting Interruption Sensor for Fiber Lasers

    Directory of Open Access Journals (Sweden)

    Benedikt Adelmann

    2015-09-01

    Full Text Available We report on an optical sensor system attached to a 4 kW fiber laser cutting machine to detect cutting interruptions. The sensor records the thermal radiation from the process zone with a modified ring mirror and optical filter arrangement, which is placed between the cutting head and the collimator. The process radiation is sensed by a Si and InGaAs diode combination with the detected signals being digitalized with 20 kHz. To demonstrate the function of the sensor, signals arising during fusion cutting of 1 mm stainless steel and mild steel with and without cutting interruptions are evaluated and typical signatures derived. In the recorded signals the piercing process, the laser switch on and switch off point and waiting period are clearly resolved. To identify the cutting interruption, the signals of both Si and InGaAs diodes are high pass filtered and the signal fluctuation ranges being subsequently calculated. Introducing a correction factor, we identify that only in case of a cutting interruption the fluctuation range of the Si diode exceeds the InGaAs diode. This characteristic signature was successfully used to detect 80 cutting interruptions of 83 incomplete cuts (alpha error 3.6% and system recorded no cutting interruption from 110 faultless cuts (beta error of 0. This particularly high detection rate in combination with the easy integration of the sensor, highlight its potential for cutting interruption detection in industrial applications.

  10. The size effect in metal cutting

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The size effect in metal cutting. 877. Figure 3. Variation of shear stress on shear plane when cutting. SAE 1112 steel (after Backer et al. 1952). Horizontal and vertical forces were measured for a number of depths of cut(t)when machining the same-sized surface as in grinding. The shear stress on the shear plane (τ) was ...

  11. Simulation of stationary sheet metal cutting processes

    NARCIS (Netherlands)

    Wisselink, H.H.; Huetink, Han

    1998-01-01

    In stationary sheet metal cutting processes, like guillotining and slitting, the sheet is cut progressively from one end to the other. This in contrary with transient processes (blanking) where the sheet is cut at once. Where transient shearing processes can be modelled in 2-D (plain strain or

  12. Air in xylem vessels of cut flowers

    NARCIS (Netherlands)

    Nijsse, J.; Meeteren, van U.; Keijzer, C.J.

    2000-01-01

    Until now all studies on the role of air emboli in the water uptake of cut flowers describe indirect methods to demonstrate the presencFe of air in the plant tissues. Using cut chrysanthemum flowers, this report is the first one that directly visualises both air and water in xylem ducts of cut

  13. The size effect in metal cutting

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    stress and strain in metal cutting is unusually high, discontinuous microcracks usually form on the metal-cutting shear plane. If the material being cut is very brittle, or the compressive stress on the shear plane is relatively low, microcracks grow into gross cracks giving rise to discontinuous chip formation. When discontinuous.

  14. Free-piston cutting machine

    Science.gov (United States)

    Ciccarelli, Gaby; Subudhi, Manomohan; Hall, Robert E.

    2000-01-01

    A cutting machine includes a gun barrel for receiving a projectile. A compression tube is disposed in flow communication with the barrel and includes a piston therein. A reservoir is disposed in flow communication with the tube and receives a first gas under pressure. A second gas fills the compression tube on a front face of the piston. And, the pressurized first gas is discharged into the tube on a back face of the piston to accelerate the piston through the tube for compressing the second gas, and in turn launching the projectile through the barrel to impact a workpiece.

  15. Laser Cutting of Carbon Fiber Fabrics

    Science.gov (United States)

    Fuchs, A. N.; Schoeberl, M.; Tremmer, J.; Zaeh, M. F.

    Due to their high weight-specific mechanical stiffness and strength, parts made from carbon fiber reinforced polymers (CFRP) are increasingly used as structural components in the aircraft and automotive industry. However, the cutting of preforms, as with most automated manufacturing processes for CFRP components, has not yet been fully optimized. This paper discusses laser cutting, an alternative method to the mechanical cutting of preforms. Experiments with remote laser cutting and gas assisted laser cutting were carried out in order to identify achievable machining speeds. The advantages of the two different processes as well as their fitness for use in mass production are discussed.

  16. Effect of Type of Cutting Tips on Cutting Forces in Turning

    Directory of Open Access Journals (Sweden)

    Polák Pavel

    2014-10-01

    Full Text Available The aim of this article is to demonstrate the efect of cutting materials and geometry of cutting tips on cutting forces in turning as well as the quality and precision of machined surface. The experiment focuses on measuring cutting forces when turning a sample of steel 11 523 at a constant feed rate and cut depth and at varying speeds of a spindle. Measurements were made using exchangeable cutting tips of diferent types. The results will be evaluated in terms of the impact of diferent characteristics of cutting tips and variable spindle speeds.

  17. Rooting of stem cuttings of ixora

    Directory of Open Access Journals (Sweden)

    Aline De Souza Silva

    2015-08-01

    Full Text Available The ixora is ornamental plant widely used in landscaping. In order to maximize the propagation of cuts, we evaluated the concentrations of auxin (indolbutiric acid and the presence of leaves on the rooting in cuts of Ixora coccinea L. The experiment was conducted in randomized block design, in factorial design 3x4, with three types of cuts (without leaf, with two or four leaves, four concentrations of indolbutiric acid (0, 1000, 2000 and 4000 mg L-1, with four replications and 10 cuts in each experimental unit. After 53 days of implantation the experiment, evaluated the survival(%, rooting(%, sprouting(%, formation of callus(%, number, length and biomass of roots formed. The interaction of the type of cuts with concentrations of auxin was not significant for any of the variables analyzed. The survival of cuttings was not influenced by the treatments. Cuts with two or four leaves presented rooting and length of roots above the cuttings without leaves. The application of auxin does not substitute the presence of leaf in cuts of ixora in vegetative propagation. The vegetative propagation by cut of ixora can be made without application of auxin, and the leaves must be maintained in the cuttings.

  18. Research of cutting power with cutting chipboards with different properties by circular saw

    Directory of Open Access Journals (Sweden)

    Stanojević Damjan M.

    2015-01-01

    Full Text Available In this paper elaborates the process of measuring cutting power which occurred during cutting six types of particle board. Chipboards with different physical and mechanical properties were cut in order to find some correlation with the cutting power ie to be able to determine the effect of moisture, density and bending strength of the plate to the cutting power. Measuring power cut was made in the workshop of the Faculty of Forestry, Belgrade, measuring the moisture and density in the laboratory for testing particle board, and the bending strength was performed in the laboratory for testing the properties of wood. During the cutting speed are changed auxiliary movements to determine the influence of the machining parameters on cutting power. Overall, it was concluded that with increasing moisture content of the work-piece cutting power decreases with increasing velocity displacement, density and bending strength of the board, required cutting power increases.

  19. Cutting method and cutting device for spent fuel rod of nuclear reactor

    International Nuclear Information System (INIS)

    Komatsu, Masahiko; Ose, Toshihiko.

    1996-01-01

    A control rod transferred under water in a vertically suspended state is postured horizontally at such a water depth that radiations can be shielded, and then it is cut to a dropping speed limiting portion and a cross-like main body. The separated cross-like main body portion is further cut in the longitudinal direction and separated into a pair of cut pieces each having an L-shaped cross section. A disk like metal saw is used as a cutting tool. Alternatively, a plasma jet cutter or a melting-type water jet cutter is used as a cutting tool. Then, since the spent control rod to be cut is postured horizontally under water, the water depth for the cutting position can be reduced. As a result, the cutting state using the cutting tool can be observed by naked eyes from the position above the water surface thereby enabling to perform the cutting operation reliably. (N.H.)

  20. The center-cut solution.

    Science.gov (United States)

    Firnstahl, T W

    1993-01-01

    Timothy Firnstahl owns five successful restaurants in Seattle, but he recently came very close to owning none. In the early 1990s, he found himself, like so many restauranteurs, facing rising costs, inefficient management, and a recession. Confronting financial annihilation, Firnstahl had to act quickly: since he had no peripherals to trim, he cut off the head of his company. Remarkably, it worked. Firnstahl's problem was his new and innovative restaurant, Sharps Fresh Roasting. The heart of the Sharps concept was a unique long-roasting technique that made lean, inexpensive meats taste as juicy and delicious as fattier, expensive cuts. The process also lent itself to faster service and lower labor costs. But it wasn't working. Sharps wasn't breaking even, and his other restaurants couldn't make up the difference. He needed a solution fast. Firnstahl got his answer from Mikhail Gorbachev: slash the centralized command and liberate the company. In doing so, he would also transfer virtually all power and responsibility to his line managers. And after five months of intensive study and planning, he accomplished what he set out to do. He fired most of his corporate staff, empowered his restaurant managers with "100% Power and Responsibility," and, finally, undertook a massive promotion campaign. A year later, Sharps Fresh Roasting is the gold mine Firnstahl always believed it could be. He's done away with bureaucracy and turned business around in a down market. All this because his managers are managing themselves.

  1. Effects of heat on cut mark characteristics.

    Science.gov (United States)

    Waltenberger, Lukas; Schutkowski, Holger

    2017-02-01

    Cut marks on bones provide crucial information about tools used and their mode of application, both in archaeological and forensic contexts. Despite a substantial amount of research on cut mark analysis and the influence of fire on bones (shrinkage, fracture pattern, recrystallisation), there is still a lack of knowledge in cut mark analysis on burnt remains. This study provides information about heat alteration of cut marks and whether consistent features can be observed that allow direct interpretation of the implemented tools used. In a controlled experiment, cut marks (n=25) were inflicted on pig ribs (n=7) with a kitchen knife and examined using micro-CT and digital microscopy. The methods were compared in terms of their efficacy in recording cut marks on native and heat-treated bones. Statistical analysis demonstrates that floor angles and the maximum slope height of cuts undergo significant alteration, whereas width, depth, floor radius, slope, and opening angle remain stable. Micro-CT and digital microscopy are both suitable methods for cut mark analysis. However, significant differences in measurements were detected between both methods, as micro-CT is less accurate due to the lower resolution. Moreover, stabbing led to micro-fissures surrounding the cuts, which might also influence the alteration of cut marks. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  2. New Modelling Strategies For Metal Cutting

    International Nuclear Information System (INIS)

    Rosa, Pedro A. R.; Martins, Paulo A. F.; Atkins, Anthony G.

    2007-01-01

    This paper draws from the 'plasticity and friction only' view of metal cutting to the presentation of new modelling strategies based on the interaction between finite elements and modern ductile fracture mechanics. The overall presentation is supported by specially designed orthogonal metal cutting experiments that were performed on Lead test specimens under laboratory-controlled conditions. Comparisons between theoretical predictions and experimental results comprise a wide range of topics such as material flow, cutting forces and specific cutting pressure. The paper demonstrates that while material flow and chip formation can be successfully modelled by traditional 'plasticity and friction only' analyses, the contribution of the fracture work involved in the formation of new surfaces is essential for obtaining good estimates of cutting forces and of the specific cutting pressure

  3. Dual-layer surface coating of PLGA-based nanoparticles provides slow-release drug delivery to achieve metronomic therapy in a paclitaxel-resistant murine ovarian cancer model.

    Science.gov (United States)

    Amoozgar, Zohreh; Wang, Lei; Brandstoetter, Tania; Wallis, Samuel S; Wilson, Erin M; Goldberg, Michael S

    2014-11-10

    Development of drug resistance is a central challenge to the treatment of ovarian cancer. Metronomic chemotherapy decreases the extent of drug-free periods, thereby hindering development of drug resistance. Intraperitoneal chemotherapy allows for treatment of tumors confined within the peritoneum, but achieving sustained tumor-localized chemotherapy remains difficult. We hypothesized that modulating the surface properties of poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles could enhance their drug retention ability and extend their release profile, thereby enabling metronomic, localized chemotherapy in vivo. Paclitaxel was encapsulated in particles coated with a layer of polydopamine and a subsequent layer of poly(ethylene glycol) (PEG). These particles achieved a 3.8-fold higher loading content compared to that of nanoparticles formulated from linear PLGA-PEG copolymers. In vitro release kinetic studies and in vivo drug distribution profiles demonstrate sustained release of paclitaxel. Although free drug conferred no survival advantage, low-dose intraperitoneal administration of paclitaxel-laden surface-coated nanoparticles to drug-resistant ovarian tumor-bearing mice resulted in significant survival benefits in the absence of any apparent systemic toxicity.

  4. Ceramic cutting tools materials, development and performance

    CERN Document Server

    Whitney, E Dow

    1994-01-01

    Interest in ceramics as a high speed cutting tool material is based primarily on favorable material properties. As a class of materials, ceramics possess high melting points, excellent hardness and good wear resistance. Unlike most metals, hardness levels in ceramics generally remain high at elevated temperatures which means that cutting tip integrity is relatively unaffected at high cutting speeds. Ceramics are also chemically inert against most workmetals.

  5. Application of response surface methodology for determining cutting ...

    Indian Academy of Sciences (India)

    by software Minitab (multiple linear regression and response surface methodology) in order to express the influence degree of the main cutting variables such as cutting speed, feed rate and depth of cut on cutting force components. These models would be helpful in selecting cutting variables for optimization of hard cutting ...

  6. Underwater laser cutting of metallic structures

    International Nuclear Information System (INIS)

    Alfille, J.P.; Schildknecht, J.; Ramaswami, V.S.

    1993-01-01

    In the frame of an european contract, the feasibility of the underwater cutting with a CO 2 laser power is studied. The aim of this work is the dismantling metallic structures of reactors pools. The paper analyzes the general concept of the experimental device, the underwater cutting head, the experimenting vessel, examples of cuttings in dismantling situation with a 500 W CO 2 laser, and examples of cuttings with a 5 kW CO 2 laser. (author). 2 refs., 9 figs., 2 tabs

  7. A cutting force model for micromilling applications

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2006-01-01

    In micro milling the maximum uncut chip thickness is often smaller than the cutting edge radius. This paper introduces a new cutting force model for ball nose micro milling that is capable of taking into account the effect of the edge radius.......In micro milling the maximum uncut chip thickness is often smaller than the cutting edge radius. This paper introduces a new cutting force model for ball nose micro milling that is capable of taking into account the effect of the edge radius....

  8. Machining Challenges: Macro to Micro Cutting

    Science.gov (United States)

    Shunmugam, M. S.

    2016-04-01

    Metal cutting is an important machining operation in the manufacture of almost all engineering components. Cutting technology has undergone several changes with the development of machine tools and cutting tools to meet challenges posed by newer materials, complex shapes, product miniaturization and competitive environments. In this paper, challenges in macro and micro cutting are brought out. Conventional and micro end-milling are included as illustrative examples and details are presented along with discussion. Lengthy equations are avoided to the extent possible, as the emphasis is on the basic concepts.

  9. Technology development for cutting a reactor pressure vessel using a mechanical cutting technique

    International Nuclear Information System (INIS)

    Watanabe, Masaaki; Miyasaka, Yasuhiko; Miyao, Hidehiko; Ooki, Arahiko; Ninomiya, Toshiaki; Koiwai, Masami

    2001-01-01

    On decommissioning of nuclear facilities, the thermal cutting technique such as an oxygen-acetylene gas cutting and a plasma arc cutting are generally used for cutting massive and thick steel structures in consideration with cutting speed and control performance. These techniques generate dust, smoke, aerosol and a large quantity of secondary waste. Mechanical cutting technique has an advantage of small amount of secondary waste, and the metal chips from the kerf recovered easily compared with these thermal cutting technique. The remote mechanical cutting system for highly activated RPV has been developed with the manner which achieves the safety and cost effectiveness. The development has been performed on consignment to RANDEC from the Science and Technology Agency of Japan. (author)

  10. Experimental research on the durability cutting tools for cutting-off steel profiles

    Directory of Open Access Journals (Sweden)

    Cristea Alexandru

    2017-01-01

    Full Text Available The production lines used for manufacturing U-shaped profiles are very complex and they must have high productivity. One of the most important stages of the fabrication process is the cutting-off. This paper presents the experimental research and analysis of the durability of the cutting tools used for cutting-off U-shaped metal steel profiles. The results of this work can be used to predict the durability of the cutting tools.

  11. 27 CFR 6.92 - Newspaper cuts.

    Science.gov (United States)

    2010-04-01

    ... OF THE TREASURY LIQUORS âTIED-HOUSEâ Exceptions § 6.92 Newspaper cuts. Newspaper cuts, mats, or engraved blocks for use in retailers' advertisements may be given or sold by an industry member to a retailer selling the industry member's products. [T.D. ATF-364, 60 FR 20423, Apr. 26, 1995] ...

  12. Automated harvesting of flowers and cuttings

    NARCIS (Netherlands)

    Rosier, J.C.; Snel, R.; Goedvolk, E.J.

    1996-01-01

    The harvesting of flowers and cuttings can be considered as a skilled task. It takes weeks of training for the pickers to harvest quality cutting at the required production rate of one per second. The skill of the pickers is the ability to execute a number of functions within a short time. The

  13. Electroencephalographic responses to neck cut and exsanguination ...

    African Journals Online (AJOL)

    user

    2016-12-09

    Dec 9, 2016 ... The data of EEG from 60-second blocks prior to neck cut to 90-second blocks post neck cut were taken for statistical analysis based on the time to .... reported an initial increase in total EEG power in lambs of different ages undergoing rubber-ring castration. In these cases, the increase in total EEG power ...

  14. Postharvest: Cut flowers and potted plants

    Science.gov (United States)

    In the past fifty years, the cut flower market has changed dramatically, from a local market with growers located on city outskirts, to a global one; flowers and cut foliage sourced from throughout the world are sold as bunches or combined into arrangements and bouquets in the major target markets. ...

  15. Cost of cutting grapevines before logging

    Science.gov (United States)

    H. Clay Smith; Paul M. Smithson

    1975-01-01

    To reduce damage to hardwood stems by grapevines, it is recommended that grapevines be cut near ground level several years before the harvest cutting. Cost of completing this practice on 117 acres supporting 22 vines per acre was found to be about $3.50 per acre.

  16. Experimental investigation of cutting parameters influence on ...

    Indian Academy of Sciences (India)

    This experimental investigation was conducted to determine the effects of cutting conditions on surface roughness and cutting forces in hard turning of X38CrMoV5-1. This steel was hardened at 50 HRC and machined with CBN tool. This is employed for the manufacture of helicopter rotor blades and forging dies. Combined ...

  17. Cutting Watermelon: Lessons in Instructional Coaching

    Science.gov (United States)

    Sandstead, Martha

    2016-01-01

    Literacy coordinator Martha Sandstead finds inspiration for her coaching work in a quote from civil rights organizer Lawrence Guyot: "Let's say you're riding past a picnic, and people are cuttin' watermelons. You don't immediately go and say, "stop the watermelon cutting" and let's talk. … You cut some watermelons, or you help…

  18. Laser cutting - trends in the development,

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    2002-01-01

    Since the laser was invented in 1960, the industrial applications of this tool has grown and grown. And - since the beginning of the 1980'ies, the major industrial application of lasers in production has been laser cutting. In this paper a short review of the development of the laser cutting...

  19. Drilling subsurface wellbores with cutting structures

    Science.gov (United States)

    Mansure, Arthur James; Guimerans, Rosalvina Ramona

    2010-11-30

    A system for forming a wellbore includes a drill tubular. A drill bit is coupled to the drill tubular. One or more cutting structures are coupled to the drill tubular above the drill bit. The cutting structures remove at least a portion of formation that extends into the wellbore formed by the drill bit.

  20. In the suppression of regge cut contributions

    International Nuclear Information System (INIS)

    Chia, S.P.

    1975-07-01

    It is shown that contributions of reggeon-pomeron cuts are suppressed in amplitudes with opposite natural to the reggeon. This suppression grows logarithmically with energy. The suppression in the πP cut is, however, found to be weak. Consequence on conspiracy is discussed

  1. Experimental investigation of cutting parameters influence on ...

    Indian Academy of Sciences (India)

    Abstract. This experimental investigation was conducted to determine the effects of cutting conditions on surface roughness and cutting forces in hard turning of. X38CrMoV5-1. This steel was hardened at 50 HRC and machined with CBN tool. This is employed for the manufacture of helicopter rotor blades and forging dies.

  2. Performance Enhancement of Abrasive Waterjet Cutting

    NARCIS (Netherlands)

    2008-01-01

    Abrasive Waterjet (AWJ) Machining is a recent non-traditional machining process. This technology is widely used in industry for cutting difficult-to-machine-materials, milling slots, polishing hard materials etc. AWJ machining has many advantages, e.g. it can cut net-shape parts, no heat is

  3. High precision tungsten cutting for optics

    International Nuclear Information System (INIS)

    Reglero, V.; Velasco, T.; Rodrigo, J.; Gasent, L.J.; Alamo, J.; Chato, R.; Ruiz Urien, I.; Santos, I.; Zarauz, J.; Clemente, G.; Sanz-Tudanca, C.; Lopez, J.L.

    2001-01-01

    The results obtained during the INTEGRAL masks development program an implementing the HURA and MURA codes on tungsten plates of different thickness are presented. Hard scientific requirements on pixels size and location tolerances (tenths of microns over large areas -1 m 2 - and thickness from 0.5 mm to 60 mm) required the set up of a dedicated program for testing cutting technologies: laser, photochemical milling, spark machining and electro discharge wire cutting. After a very intensive test campaign the wire cutting process was selected as the optimum technology for code manufacturing . Accuracies achieved an the code cutting fulfill scientific requirements. In fact, they are 5 times better than required. Pixel size and centroids location accuracies of 0.01 mm over a 1 m 2 area have been obtained for the 10,000 pixels on IBIS, 100 pixels on SPI and 24000 pixels on JEM-X masks. Comparative results among different cutting technologies are also discussed. (author)

  4. Cutting as a continuous business process

    Directory of Open Access Journals (Sweden)

    Miro Gradišar

    2009-11-01

    Full Text Available A review of state-of-the-art methods for cutting stock problem optimisation shows that the current methods lead to near-optimum results for the instantaneous optimisation of trim loss. Further optimisation of this activity would not bring a considerable improvement. Therefore, the paper treats cutting stock as a continuous business process and not as an isolated activity. An exact method for a general one-dimensional cutting stock problem is presented and tested. The method is mainly suitable for smaller orders. It is then applied to continuous cutting and used to develop a method for assessing cutting costs in consecutive time periods. The modified method finds a good solution over the whole time-span, rather than just local optima.

  5. Effects of Cutting Tool Parameters on Vibration

    Directory of Open Access Journals (Sweden)

    Ince Mehmet Alper

    2016-01-01

    Full Text Available This paper presents of the influence on vibration of Co28Cr6Mo medical alloy machined on a CNC lathe based on cutting parameters (rotational speed, feed rate, depth of cut and tool tip radius. The influences of cutting parameters have been presented in graphical form for understanding. To achieve the minimum vibration, the optimum values obtained for rpm, feed rate, depth of cut and tool tip radius were respectively, 318 rpm, 0.25 mm/rev, 0.9 mm and 0.8 mm. Maximum vibration has been revealed the values obtained for rpm, feed rate, depth of cut and tool tip radius were respectively, 636 rpm, 0.1 mm/rev, 0,5 mm and 0.8 mm.

  6. Changing cultural attitudes towards female genital cutting.

    Science.gov (United States)

    Vogt, Sonja; Mohmmed Zaid, Nadia Ahmed; El Fadil Ahmed, Hilal; Fehr, Ernst; Efferson, Charles

    2016-10-27

    As globalization brings people with incompatible attitudes into contact, cultural conflicts inevitably arise. Little is known about how to mitigate conflict and about how the conflicts that occur can shape the cultural evolution of the groups involved. Female genital cutting is a prominent example. Governments and international agencies have promoted the abandonment of cutting for decades, but the practice remains widespread with associated health risks for millions of girls and women. In their efforts to end cutting, international agents have often adopted the view that cutting is locally pervasive and entrenched. This implies the need to introduce values and expectations from outside the local culture. Members of the target society may view such interventions as unwelcome intrusions, and campaigns promoting abandonment have sometimes led to backlash as they struggle to reconcile cultural tolerance with the conviction that cutting violates universal human rights. Cutting, however, is not necessarily locally pervasive and entrenched. We designed experiments on cultural change that exploited the existence of conflicting attitudes within cutting societies. We produced four entertaining movies that served as experimental treatments in two experiments in Sudan, and we developed an implicit association test to unobtrusively measure attitudes about cutting. The movies depart from the view that cutting is locally pervasive by dramatizing members of an extended family as they confront each other with divergent views about whether the family should continue cutting. The movies significantly improved attitudes towards girls who remain uncut, with one in particular having a relatively persistent effect. These results show that using entertainment to dramatize locally discordant views can provide a basis for applied cultural evolution without accentuating intercultural divisions.

  7. Development of a dynamic in vitro model of a stented blood vessel to evaluate the effects of stent strut material selection and surface coating on smooth muscle cell response

    Science.gov (United States)

    Winn, Bradley Huegh

    formation of this new tissue, primarily consisting of VSMCs of the synthetic phenotype and their subsequent extracellular matrix, is the sole causation of in-stent restenosis since the stent serves to prevent elastic recoil and negative remodeling. This doctoral research program is focused on endovascular stent biomaterials science and engineering. Overall, this doctoral project is founded on the hypothesis that smooth muscle cell hyperplasia, as an important causative factor for vascular restenosis following endovascular stent deployment, is triggered by the various effects of stent strut contact on the vessel wall including contact forces and material biocompatibility. In this program, a dynamic in vitro model of a stented blood vessel aimed at evaluating the effect of stent strut material selection, and surface coating on smooth muscle cell response was developed. The in vitro stented artery model was validated through the proliferation of VSMC in contact with stent struts. Additionally, it was demonstrated that, with respect to known biocompatible materials such as Nitinol and 316L stainless steel, DNA synthesis and alpha-actin expression, as indicators of VSMC phenotype, are independent of stent material composition. Furthermore, hydroxyapatite was shown to be a biocompatible stent surface coating with acceptable post-strain integrity. This coating was shown in a feasibility study to be capable of serving as a favorable drug delivery platform able to reliably deliver locally therapeutic doses of bisphosphonates, such as alendronate, to control VSMC proliferation in an in vitro model of a stented blood vessel. This stent coating/drug combination may be effective for reducing restenosis as a result of VSMC hyperplasia in vivo.

  8. Surface coating for blood-contacting devices

    Science.gov (United States)

    Nair, Ajit Kumar Balakrishnan

    The major problems always encountered with the blood-contacting surfaces are their compatibility, contact blood damage, and thrombogenicity. Titanium nitride (TiN) is a hard, inert, ceramic material that is widely used in the engineering industry. TiN has been proven to be a good biomaterial in its crystalline form, in orthopedic, and in tissue implant applications. This dissertation describes a method to coat amorphous TiN on the blood-contacting surfaces of certain medical devices using the room-temperature sputtering process and to characterize, to test, and to evaluate the coating for a reliable, durable, and compatible blood-contacting surface The blood-compatibility aspects were evaluated with standard, established protocols and procedures to prove the feasibility. An amorphous TiN coating is developed, characterized, tested, and blood compatibility evaluated by applying to the blood-contacting surfaces of stainless steel, catheters, and blood filters. The flexibility characteristics were proven by applying it to the diaphragms of the pulsatile pneumatic ventricular assist device. The results show that amorphous titanium nitride is flexible and adherent to polymeric substrates like polyurethane and polyester. Blood compatibility evaluation showed comparable results with catheters and superior behavior with stainless steel and polyester filters. It is concluded that amorphous titanium nitride can be considered to be applied to the surfaces of some of the medical devices in order to improve blood compatibility.

  9. Superhydrophobic Surface Coatings for Microfluidics and MEMs.

    Energy Technology Data Exchange (ETDEWEB)

    Branson, Eric D.; Singh, Seema [Sandia National Laboratories, Livermore, CA; Houston, Jack E.; van Swol, Frank B.; Brinker, C. Jeffrey

    2006-11-01

    Low solid interfacial energy and fractally rough surface topography confer to Lotus plants superhydrophobic (SH) properties like high contact angles, rolling and bouncing of liquid droplets, and self-cleaning of particle contaminants. This project exploits the porous fractal structure of a novel, synthetic SH surface for aerosol collection, its self-cleaning properties for particle concentration, and its slippery nature 3 to enhance the performance of fluidic and MEMS devices. We propose to understand fundamentally the conditions needed to cause liquid droplets to roll rather than flow/slide on a surface and how this %22rolling transition%22 influences the boundary condition describing fluid flow in a pipe or micro-channel. Rolling of droplets is important for aerosol collection strategies because it allows trapped particles to be concentrated and transported in liquid droplets with no need for a pre-defined/micromachined fluidic architecture. The fluid/solid boundary condition is important because it governs flow resistance and rheology and establishes the fluid velocity profile. Although many research groups are exploring SH surfaces, our team is the first to unambiguously determine their effects on fluid flow and rheology. SH surfaces could impact all future SNL designs of collectors, fluidic devices, MEMS, and NEMS. Interfaced with inertial focusing aerosol collectors, SH surfaces would allow size-specific particle populations to be collected, concentrated, and transported to a fluidic interface without loss. In microfluidic systems, we expect to reduce the energy/power required to pump fluids and actuate MEMS. Plug-like (rather than parabolic) velocity profiles can greatly improve resolution of chip-based separations and enable unprecedented control of concentration profiles and residence times in fluidic-based micro-reactors. Patterned SH/hydrophilic channels could induce mixing in microchannels and enable development of microflow control elements. Acknowledgements This work was funded by Sandia National Laboratory's Laboratory Directed Research & Development program (LDRD). Some coating processes were conducted in the cleanroom facility located at the University of New Mexico's Center for High Technology Materials (CHTM). SEM images were performed at UNM's Center for Micro-Engineering on equipment funded by a NSF New Mexico EPSCoR grant. 4

  10. Evaporated Lithium Surface Coatings in NSTX

    International Nuclear Information System (INIS)

    Kugel, H.W.; Mansfield, D.; Maingi, Rajesh; Bell, M.G.; Bell, R.E.; Allain, J.P.; Gates, D.; Gerhardt, S.P.; Kaita, R.; Kallman, J.; Kaye, S.; LeBlanc, B.P.; Majeski, R.; Menard, J.; Mueller, D.; Ono, M.; Paul, S.; Raman, R.; Roquemore, A.L.; Ross, P.W.; Sabbagh, S.A.; Schneider, H.; Skinner, C.H.; Soukhanovskii, V.; Stevenson, T.; Timberlake, J.; Wampler, W.R.; Wilgen, John B.; Zakharov, L.E.

    2009-01-01

    Two lithium evaporators were used to evaporate more than 100 g of lithium on to the NSTX lower divertor region. Prior to each discharge, the evaporators were withdrawn behind shutters, where they also remained during the subsequent HeGDC applied for periods up to 9.5 min. After the HeGDC, the shutters were opened and the LITERs were reinserted to deposit lithium on the lower divertor target for 10 min, at rates of 10-70 mg/min, prior to the next discharge. The major improvements in plasma performance from these lithium depositions include: (1) plasma density reduction as a result of lithium deposition; (2) suppression of ELMs; (3) improvement of energy confinement in a low-triangularity shape; (4) improvement in plasma performance for standard, high-triangularity discharges: (5) reduction of the required HeGDC time between discharges; (6) increased pedestal electron and ion temperature; (7) reduced SOL plasma density; and (8) reduced edge neutral density.

  11. Evaporated Lithium Surface Coatings in NSTX

    International Nuclear Information System (INIS)

    Kugel, H.W.; Mansfield, D.; Maingi, R.; Bel, M.G.; Bell, R.E.; Allain, J.P.; Gates, D.; Gerhardt, S.; Kaita, R.; Kallman, J.; Kaye, S.; LeBlanc, B.; Majeski, R.; Menard, J.; Mueller, D.; Ono, M.

    2009-01-01

    Two lithium evaporators were used to evaporate more than 100 g of lithium on to the NSTX lower divertor region. Prior to each discharge, the evaporators were withdrawn behind shutters, where they also remained during the subsequent HeGDC applied for periods up to 9.5 min. After the HeGDC, the shutters were opened and the LITERs were reinserted to deposit lithium on the lower divertor target for 10 min, at rates of 10-70 mg/min, prior to the next discharge. The major improvements in plasma performance from these lithium depositions include: (1) plasma density reduction as a result of lithium deposition; (2) suppression of ELMs; (3) improvement of energy confinement in a low-triangularity shape; (4) improvement in plasma performance for standard, high-triangularity discharges; (5) reduction of the required HeGDC time between discharges; (6) increased pedestal electron and ion temperature; (7) reduced SOL plasma density; and (8) reduced edge neutral density

  12. Stresses and Cracks in Surface Coatings

    DEFF Research Database (Denmark)

    Horsewell, Andy

    2000-01-01

    This extended abstract of the talk to be given at the Danish Metallurgical Society, Winter Meeting 1999, gives an outline of the areas of interest in current projects in wear and corrosion resistant coatings at Materials Technology, Technical University of Denmark (IPT, Materialeteknologi, DTU......). It also briefly describes our method of approach in analysing new coating / substrate combinations or new materials processing techniques for producing a given coating. We strive to combine, often in collaboration with others, a fundamental understanding of microstructure, mechanical properties...

  13. Surface coatings deposited by CVD and PVD

    International Nuclear Information System (INIS)

    Gabriel, H.M.

    1982-01-01

    The demand for wear and corrosion protective coatings is increasing due to economic facts. Deposition processes in gas atmospheres like the CVD and PVD processes attained a tremendous importance especially in the field of the deposition of thin hard refractory and ceramic coatings. CVD and PVD processes are reviewed in detail. Some examples of coating installations are shown and numerous applications are given to demonstrate the present state of the art. (orig.) [de

  14. Laser circular cutting of Kevlar sheets: Analysis of thermal stress filed and assessment of cutting geometry

    Science.gov (United States)

    Yilbas, B. S.; Akhtar, S. S.; Karatas, C.

    2017-11-01

    A Kevlar laminate has negative thermal expansion coefficient, which makes it difficult to machine at room temperaures using the conventional cutting tools. Contararily, laser machining of a Kevlar laminate provides advantages over the conventional methods because of the non-mechanical contact between the cutting tool and the workpiece. In the present study, laser circular cutting of Kevlar laminate is considered. The experiment is carried out to examine and evaluate the cutting sections. Temperature and stress fields formed in the cutting section are simulated in line with the experimental study. The influence of hole diameters on temperature and stress fields are investigated incorporating two different hole diameters. It is found that the Kevlar laminate cutting section is free from large size asperities such as large scale sideways burnings and attachemnt of charred residues. The maximum temperature along the cutting circumference remains higher for the large diameter hole than that of the small diameter hole. Temperature decay is sharp around the cutting section in the region where the cutting terminates. This, in turn, results in high temperature gradients and the thermal strain in the cutting region. von Mises stress remains high in the region where temperature gradients are high. von Mises stress follows similar to the trend of temperature decay around the cutting edges.

  15. Modeling and analysis of the chip formation and transient cutting force during elliptical vibration cutting process

    Science.gov (United States)

    Lin, Jieqiong; Guan, Liang; Lu, Mingming; Han, Jinguo; Kan, Yudi

    2017-12-01

    In traditional diamond cutting, the cutting force is usually large and it will affect tool life and machining quality. Elliptical vibration cutting (EVC) as one of the ultra-precision machining technologies has a lot of advantages, such as reduces cutting force, extend tool life and so on. It's difficult to predict the transient cutting force of EVC due to its unique elliptical motion trajectory. Study on chip formation will helpfully to predict cutting force. The geometric feature of chip has important effects on cutting force, however, few scholars have studied the chip formation. In order to investigate the time-varying cutting force of EVC, the geometric feature model of chip is established based on analysis of chip formation, and the effects of cutting parameters on the geometric feature of chip are analyzed. To predict transient force quickly and effectively, the geometric feature of chip is introduced into the cutting force model. The calculated results show that the error between the predicted cutting force in this paper and that in the literature is less than 2%, which proves its feasibility.

  16. Modeling and analysis of the chip formation and transient cutting force during elliptical vibration cutting process

    Directory of Open Access Journals (Sweden)

    Jieqiong Lin

    2017-12-01

    Full Text Available In traditional diamond cutting, the cutting force is usually large and it will affect tool life and machining quality. Elliptical vibration cutting (EVC as one of the ultra-precision machining technologies has a lot of advantages, such as reduces cutting force, extend tool life and so on. It’s difficult to predict the transient cutting force of EVC due to its unique elliptical motion trajectory. Study on chip formation will helpfully to predict cutting force. The geometric feature of chip has important effects on cutting force, however, few scholars have studied the chip formation. In order to investigate the time-varying cutting force of EVC, the geometric feature model of chip is established based on analysis of chip formation, and the effects of cutting parameters on the geometric feature of chip are analyzed. To predict transient force quickly and effectively, the geometric feature of chip is introduced into the cutting force model. The calculated results show that the error between the predicted cutting force in this paper and that in the literature is less than 2%, which proves its feasibility.

  17. Restraining and neck cutting or stunning and neck cutting of veal calves.

    Science.gov (United States)

    Lambooij, E; van der Werf, J T N; Reimert, H G M; Hindle, V A

    2012-05-01

    Brain and heart activities were measured in 31 veal calves during restraining and rotating followed by neck cutting with or without stunning to evaluate welfare. After neck cutting correlation dimension analyses and %power of EEG beta wave fraction decreased gradually to lower values resulting in an induction of unconsciousness lasting on average 80s. Corneal reflex response ceased 135±57s after neck cutting. The CD scores and the %power of beta waves fell immediately after post-cut captive bolt and pre-cut electrical stunning to levels indicating unconsciousness. Heart rate in lairage increased upon entrance to the restrainer and again after rotation, heart rate variability decreased. Rotating the restrainer 90°, 120° or 180° compromised veal calf welfare and should be avoided. It is recommended to use post-cut captive bolt stunning or pre-cut electrical stunning inducing immediate unconsciousness. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Mist, substrate water potential and cutting water potential influence rooting of stem cuttings of loblolly pine.

    Science.gov (United States)

    Lebude, Anthony V; Goldfarb, Barry; Blazich, Frank A; Wise, Farrell C; Frampton, John

    2004-07-01

    We investigated the influence of cutting water potential (Psicut) on rooting of juvenile hardwood (dormant) and softwood (succulent) stem cuttings of loblolly pine (Pinus taeda L.) propagated under varying substrate water potentials (Psisub) and volumes of mist application. Mist treatment and Psisub contributed to the Psicut of unrooted stem cuttings. When Psisub was held constant across mist treatments, mist treatment contributed strongly to Psicut. Substrate water potential affected rooting percentage when mist treatment was sub-optimal or excessive, otherwise mist treatment had a stronger effect than Psisub on rooting percentage. Cuttings rooted best when subjected to moderate cutting water potentials (-0.5 to -1.2 MPa) during the initial 4 or 5 weeks of the rooting period. Cuttings experiencing either severe water deficit or no water deficit rooted poorly. We conclude that the rooting environment should impose a moderate water stress on loblolly pine stem cuttings to achieve optimum rooting. Copyright 2004 Heron Publishing

  19. Laser cutting of sheets for Tailored Blanks

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1999-01-01

    Over the past few years there has been an enormous increase in the use of tailored blanks, especially in the automotive industry. Often the sheets for tailored blanks are shear cut, but results have been reported that the allowable sheet gap distance should not exceed 0.1 mm in order to obtain...... sound welds. Laser cutting the sheets may therefore be an alternative to shear cutting, if the cut kerf squareness can be kept below 0.05 mm.In a number of systematic laboratory experiments the effects of the major process parameters in laser cutting have been investigated. Each cut was quantified...... by the squareness, the surface roughness and the burr height. Mild steel as well as high strength steel with and with out galvanisation with thickness' of 0.7(5) and 1.25 were used.In the tests the difference in cut quality between a 5" and a 7.5" focusing lens were tested and the effect of using pulsed mode laser...

  20. Deferment cutting in Appalachian hardwoods: the what, whys, and hows

    Science.gov (United States)

    H. Clay Smith; Gary W. Miller

    1991-01-01

    Deferment cutting is a regeneration practice that resembles a seed-tree or shelterwood cutting. The difference is that residual trees are not cut when the reproduction becomes established. Instead, residual trees are left until new reproduction matures to sawtimber size, and another regeneration cut is the silvicultural objective. Hence, with deferment cutting specific...

  1. Reachability cuts for the vehicle routing problem with time windows

    DEFF Research Database (Denmark)

    Lysgaard, Jens

    2004-01-01

    This paper introduces a class of cuts, called reachability cuts, for the Vehicle Routing Problem with Time Windows (VRPTW). Reachability cuts are closely related to cuts derived from precedence constraints in the Asymmetric Traveling Salesman Problem with Time Windows and to k-path cuts...

  2. Mining Eclipse for CrossCutting

    OpenAIRE

    Breu, Silvia; Zimmermann, Thomas; Lindig, Christian

    2007-01-01

    Software may contain functionality that does not align with its architecture. Such cross-cutting concerns do not exist from the beginning but emerge over time. By analysing where developers add code to a program, our history-based mining identifies cross-cutting concerns in a two-step process. First, we mine CVS archives for sets of methods where a call to a specific single method was added. In a second step, simple cross-cutting concerns are combined to complex cross-...

  3. Reconfigurable manufacturing execution system for pipe cutting

    Science.gov (United States)

    Yin, Y. H.; Xie, J. Y.

    2011-08-01

    This article presents a reconfigurable manufacturing execution system (RMES) filling the gap between enterprise resource planning and resource layer for pipe-cutting production with mass customisation and rapid adaptation to dynamic market, which consists of planning and scheduling layer and executive control layer. Starting from customer's task and process requirements, the cutting trajectories are planned under generalised mathematical model able to reconfigure in accordance with various intersecting types' joint, and all tasks are scheduled by nesting algorithm to maximise the utilisation rate of rough material. This RMES for pipe cutting has been effectively implemented in more than 100 companies.

  4. Cut elimination in multifocused linear logic

    DEFF Research Database (Denmark)

    Guenot, Nicolas; Brock-Nannestad, Taus

    2015-01-01

    We study cut elimination for a multifocused variant of full linear logic in the sequent calculus. The multifocused normal form of proofs yields problems that do not appear in a standard focused system, related to the constraints in grouping rule instances in focusing phases. We show that cut...... elimination can be performed in a sensible way even though the proof requires some specific lemmas to deal with multifocusing phases, and discuss the difficulties arising with cut elimination when considering normal forms of proofs in linear logic....

  5. Laser cutting with chemical reaction assist

    Science.gov (United States)

    Gettemy, Donald J.

    1992-01-01

    A method for cutting with a laser beam where an oxygen-hydrocarbon reaction is used to provide auxiliary energy to a metal workpiece to supplement the energy supplied by the laser. Oxygen is supplied to the laser focus point on the workpiece by a nozzle through which the laser beam also passes. A liquid hydrocarbon is supplied by coating the workpiece along the cutting path with the hydrocarbon prior to laser irradiation or by spraying a stream of hydrocarbon through a nozzle aimed at a point on the cutting path which is just ahead of the focus point during irradiation.

  6. Cutting metals with a water jet

    International Nuclear Information System (INIS)

    Ehlbeck, U.; Corin, C.O.

    1986-01-01

    By the use of solid matter as additives in cutting tooths it is now also possible to cut metals (steel, high-alloy steel, titanium, aluminium, lead). The same standard high-pressure elements for the generation of a water jet are used to cut metals, glass, and ceramics. But within the tool the water jet first of all enters a mixer chamber where it takes in a predosed abrasive by the action of an injector. At the exit end of the mixer chamber, the jet is concentrated again. New applications of this 'Paser' system (particle-stream-erosion cutting process, a registered trade mark), which is also called abrasive jet process, are in aviation and space travel, nuclear technology and so forth. (orig./HP) [de

  7. Spending and cutting are two different worlds

    DEFF Research Database (Denmark)

    Houlberg, Kurt; Olsen, Asmus Leth; Pedersen, Lene Holm

    2016-01-01

    This article investigates politicians’ preferences for cutting and spending. The research questions are where do politicians prefer to cut, where do they prefer to spend and how is this influenced by political ideology? These questions are investigated in a large-scale survey experiment fielded...... to Danish local councillors, who are randomly assigned to a decision-making situation, where the block grant provided to their municipality is either increased or reduced. The results show that the politicians’ preferences for cutting and spending are asymmetric, in the sense that the policy areas, which...... are assigned the least cuts when the grant is reduced, are rarely the ones which are assigned extra money when the grant is increased. Areas with well-organised interests and a target group which is perceived as deserving are granted more money, whereas policy areas where the target group is perceived as less...

  8. Experimental investigation of cutting parameters influence on ...

    Indian Academy of Sciences (India)

    38, Part 3, June 2013, pp. 429–445. c Indian Academy of Sciences. Experimental investigation of cutting parameters influence on surface roughness and cutting forces in hard turning of X38CrMoV5-1 with CBN tool. H AOUICI1,2,∗. , M A YALLESE2, A BELBAH2, M F AMEUR1 and M ELBAH2. 1ENST-ex CT siège DG. SNVI ...

  9. Development of a tuneable channel cut crystal

    Science.gov (United States)

    Treimer, W.; Strobl, M.; Hilger, A.

    2001-10-01

    We have developed the first tuneable channel cut crystal for ultra small angle neutron scattering and neutron optical experiments. The Darwin range of a perfect crystal can be reduced down to a fraction of its natural width. This “Darwin reduction” was realised without any change of the beam geometry which yields an intensity gain relative to conventional asymmetric Bragg diffraction. With such tuneable channel cut crystal peaks nearly δ-peaks can experimentally be realised.

  10. Preparation of one-step NiO/Ni-CGO composites using factorial design; Efeitos do processamento e do teor de formador de poros na microestrutura de cermets Ni-CGO

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.J.M. de; Sousa, A R.O. de; Camposa, L.F.A.; Macedo, D.A. [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Loureiro, F. J.A.; Fagg, D.P., E-mail: allanjp1993@hotmail.com [Universidade de Aveiro (Portugal)

    2016-07-01

    This work deals with the synthesis, processing and characterization of NiO/Ni- CGO composite materials as potential solid oxide fuel cell (SOFC) anodes. The particulate materials were obtained by a one-step synthesis method and characterized by thermal analysis (prior to calcination) and X-ray diffraction (calcined powder). The ceramic processing of samples containing from 30 to 70 wt.% NiO was carried out by factorial design. Besides the NiO content controlled during the chemical synthesis, the impacts of the pore-former content (citric acid, used in proportions of 0, 7.5 and 15 wt.%) and the sintering temperature (1300, 1350 and 1400 °C) were also investigated. The open porosity of NiO-CGO composites and reduced Ni-CGO cermets was modeled as a function of factors (NiO content, citric acid content and sintering temperature) and interaction of factors. (author)

  11. Development of cutting technique of magnetic alloys core

    International Nuclear Information System (INIS)

    Nomura, Masahiro; Tamura, Fumihiko; Schnase, Alexander; Yamamoto, Masanobu; Anami, Shozo; Ezura, Eizi; Hara, Keigo; Ohmori, Chihiro; Takagi, Akira; Yoshii, Masahito

    2005-01-01

    A new type of rf cavity using a high permeability magnetic alloy (MA) will be used for the J-PARC high intense proton synchrotrons. The cut core configuration has been adopted to get the optimum Q-value of MA core. We observed the cut surface of MA cores obtained by water jet and grind stone cut. The results show that the roughness of the cut surfaces by grind stone cut is much smaller than by water jet cut so that the cut core by grind stone cut has a possibility to reduce the temperature rise around the cut surface. We developed a grind stone cutting machine for large core and cut large cores by using this machine. High power test of those cores have been performed and we did not observe the temperature rise around the cut surface. (author)

  12. Microstructure and thermal stability of Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coatings

    Science.gov (United States)

    Meng, Jian-ping; Guo, Rui-rui; Li, Hu; Zhao, Lu-ming; Liu, Xiao-peng; Li, Zhou

    2018-05-01

    Solar selective absorbing coatings play a valuable role in photo-thermal conversion for high efficiency concentrating solar power systems (CSP). In this paper, a novel Cu/Zr0.3Al0.7N/Zr0.2Al0.8N/Al34O60N6 cermet-based solar selective absorbing coating was successfully deposited by ion beam assisted deposition. The optical properties, microstructure and element distribution in depth were investigated by spectroscopic ellipsometry, UV-vis-NIR spectrophotometer, transmission electron microscope (TEM) and Auger electron spectroscopy (AES), respectively. A high absorptance of 0.953 and a low thermal emittance of 0.079 at 400 °C are obtained by the integral computation according to the whole reflectance from 300 nm to 28,800 nm. After annealing treatment at 400 °C (in vacuum) for 192 h, the deposited coating exhibits the high thermal stability. Whereas, the photothermal conversion efficiency decreases from 12.10 to 6.86 due to the emittance increase after annealing at 600 °C for 192 h. Meanwhile, the nitrogen atom in the Zr0.3Al0.7N sub-layer diffuses toward the adjacent sub-layer due to the spinodal decomposition of metastable c-ZrAlN and the phase transition from c-AlN to h-AlN, which leads to the composition of the Zr0.3Al0.7N sub-layer deviates the initial design. This phenomenon has a guide effect for the thermal-stability improvement of cermet coatings. Additionally, a serious diffusion between copper and silicon substrate also contributes to the emittance increase.

  13. Under water cutting of metallic materials by laser

    International Nuclear Information System (INIS)

    Jha, S.K.; Ghosal, Swati; Goswami, G.L.

    1994-01-01

    A laser cutting assembly has been made which allows laser beam to be focused on a job submerged under water, even though the laser head remains outside water. Under water cutting will be very useful for cutting of radioactive materials inside pool or storage bay. This can also be used for reactive materials like uranium etc which otherwise are difficult to cut in open atmosphere as they catch fire. The effect of cutting parameters on the cut quality and also comparison between under-water cutting and open air-cutting is discussed. (author). 2 refs., 1 tab

  14. Cutting meat with bone using an ultrahigh pressure abrasive waterjet.

    Science.gov (United States)

    Wang, J; Shanmugam, D K

    2009-04-01

    An experimental study of abrasive waterjet (AWJ) cutting of beef, pork and lamb meat with and without bone is presented. Salt particles were used as the abrasives. It has been found that an AWJ could significantly increase the depth of cut with much improved cut quality in cutting pure meat as compared to plain (or pure) waterjet cutting, while a plain waterjet was incapable of cutting bone satisfactorily. The study shows that AWJ cutting produced a very narrow kerf of less than 1mm and hence resulted in mush less meat loss than the traditional cutting processes, and meat can be cut at room temperature to eliminate the freezing or chilling costs. It is shown that a traverses speed of 20mm/s can be used to cut through 44mm thick beef rib bones with good cut quality. When slicing pure meat of 150mm thickness, the traverse speed of 66.67mm/s can yield very good cut quality. It is suggested that AWJ cutting is a viable technology for meat cutting. Plausible trends for the depth of cut, cutting rate and cut quality with respect to the process variables are discussed. Recommendations are finally made for the selection of the most appropriate process parameters for cutting meat of a given thickness.

  15. Laser cutting of various materials: Kerf width size analysis and life cycle assessment of cutting process

    Science.gov (United States)

    Yilbas, Bekir Sami; Shaukat, Mian Mobeen; Ashraf, Farhan

    2017-08-01

    Laser cutting of various materials including Ti-6Al-4V alloy, steel 304, Inconel 625, and alumina is carried out to assess the kerf width size variation along the cut section. The life cycle assessment is carried out to determine the environmental impact of the laser cutting in terms of the material waste during the cutting process. The kerf width size is formulated and predicted using the lump parameter analysis and it is measured from the experiments. The influence of laser output power and laser cutting speed on the kerf width size variation is analyzed using the analytical tools including scanning electron and optical microscopes. In the experiments, high pressure nitrogen assisting gas is used to prevent oxidation reactions in the cutting section. It is found that the kerf width size predicted from the lump parameter analysis agrees well with the experimental data. The kerf width size variation increases with increasing laser output power. However, this behavior reverses with increasing laser cutting speed. The life cycle assessment reveals that material selection for laser cutting is critical for the environmental protection point of view. Inconel 625 contributes the most to the environmental damages; however, recycling of the waste of the laser cutting reduces this contribution.

  16. Basic study on cermet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Takano, Kimihide; Sato, Seichi; Ohashi, Hiroshi [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering; Minato, Kazuo; Fukuda, Kosaku

    1996-01-01

    Cesium is a major nuclear fission product which is volatile and corrosive and it is able to interact with fuels, cladding tubes and/or other fission products resulting in productions of various compounds. The presence of those compounds may give rise to physical and chemical interactions between fuels and the cladding tube, resulting in changes in their heat transfer coefficients. In this study, some cesium uranates were prepared in the laboratory. Then, Cs{sub 2}UO{sub 4}, Cs{sub 2}U{sub 2}O{sub 7} and Cs{sub 2}U{sub 4}O{sub 12} were thermodynamically analyzed by phase equilibrium calculation using the calculation code, CHEMSAGE. And physicochemical properties of these compounds were investigated. The reaction conditions for producing the three compounds were determined. The equilibrium diagram revealed that Cs{sub 2}UO{sub 4} is stable in a wider range for the partial pressures of oxygen and cesium than Cs{sub 2}U{sub 2}O{sub 7} or Cs{sub 2}U{sub 4}O{sub 12}. Some orange colored product was obtained from the reaction of Cs{sub 2}CO{sub 3} and U{sub 3}O{sub 8} in an electric furnace and Cs{sub 2}U{sub 2}O{sub 7} but not Cs{sub 2}UO{sub 4} was identified by X-ray diffraction of the product. (M.N.)

  17. Identification of cutC and cutF (nlpE) genes involved in copper tolerance in Escherichia coli.

    OpenAIRE

    Gupta, S D; Lee, B T; Camakaris, J; Wu, H C

    1995-01-01

    It has been suggested previously that copper transport in Escherichia coli is mediated by the products of at least six genes, cutA, cutB, cutC, cutD, cutE, and cutF. A mutation in one or more of these genes results in an increased copper sensitivity (D. Rouch, J. Camakaris, and B. T. O. Lee, p. 469-477, in D. H. Hamer and D. R. Winge, ed., Metal Ion Homeostasis: Molecular Biology and Chemistry, 1989). Copper-sensitive cutC and cutF mutants were transformed with a genomic library of E. coli, a...

  18. Characterisation of aerosols produced by laser cutting

    International Nuclear Information System (INIS)

    Fauvel, S.; Pilot, G.; Dinechin, G. de; Gosse, X.; Arnaud, P.

    2007-01-01

    Powerful lasers represent a promising alternative solution to traditional cutting processes used in dismantling nuclear equipments. The use of optical fibers has an unquestionable advantage when dealing with airtight workshops. A study funded by COGEMA Marcoule was undertaken by IRSN/SERAC in collaboration with GIP/GERAILP in order to characterise the aerosols emitted by the cutting of evaporators elements with a 4 kW continuous wave Nd:YAG laser. For this study, laser cutting has been carried out in a tight room of 35 m 3 connected to a particle sampling pipe. Iso-kinetic samplers allowed the measurement of the aerosol concentration. A diffusional and inertial spectrometer (SDI 2001) - an Andersen impinger coupled to a diffusion battery - provided the size distribution. An electrostatic filter used upstream a HEPA filter, itself placed before the extractor fan, collected the majority of the emitted aerosol. Its efficiency was measured and controlled throughout the experiments. The results show the influence of the cutting conditions on the characteristics of the aerosol, and allow a comparison with other cutting tools. (authors)

  19. Budget Cuts: Financial Aid Offices Face Budget Cuts and Increasing Workload. Quick Scan Survey Results

    Science.gov (United States)

    National Association of Student Financial Aid Administrators (NJ1), 2010

    2010-01-01

    The majority of college financial aid offices have seen cuts to their operating budgets this year compared to the 2007-08 academic year when the recession began, according to the National Association of Student Financial Aid Administrator's latest QuickScan Survey. Sixty-two percent of financial aid offices reported operating budget cuts this year…

  20. Effects of cutting and maturity on antioxidant activity of fresh-cut tomatoes

    NARCIS (Netherlands)

    Moreira Lana, M.; Tijskens, L.M.M.

    2006-01-01

    To investigate the changes in total antioxidant activity of fresh-cut tomato during storage, tomato fruits harvested at three different stages of maturity were cut into 7-mm thick slices and stored at 5 °C. Intact fruits were stored in the same conditions as a control. The antioxidant activity was

  1. COMPUTER AIDED DESIGN OF CUTTING TOOLS

    Directory of Open Access Journals (Sweden)

    Jakub Matuszak

    2015-11-01

    Full Text Available Correct and stable machining process requires an appropriate cutting tool. In most cases the tool can be selected by using special tool catalogs often available in online version. But in some cases there is a need to design unusual tools, for special treatment, which are not available in tool manufacturers’ catalogs. Proper tool design requires strength and geometric calculations. Moreover, in many cases specific technical documentation is required. By using Computer Aided Design of cutting tools this task can be carried out quickly and with high accuracy. Cutting tool visualization in CAD programs gives a clear overview of the design process. Besides, these programs provide the ability to simulate real machining process. Nowadays, 3D modeling in CAD programs is a fundamental tool for engineers. Therefore, it is important to use them in the education process.

  2. Imaging, cutting, and collecting instrument and method

    Science.gov (United States)

    Tench, R.J.; Siekhaus, W.J.; Balooch, M.; Balhorn, R.L.; Allen, M.J.

    1995-10-31

    Instrumentation and techniques are described to image small objects, such as but not limited to individual human chromosomes, with nanometer resolution. This instrument and method are also used to cut-off identified parts of objects, to move around and manipulate the cut-off parts on the substrate on which they are being imaged to predetermined locations on the substrate, and to remove the cut-off parts from the substrate. This is accomplished using an atomic force microscope (AFM) and by modification of the conventional cantilever stylus assembly of an AFM. The plural cantilevers are used with either sharp-tips or knife-edges. In addition, the invention can be utilized for measuring the hardness of materials. 10 figs.

  3. Basics of cutting and abrasive processes

    CERN Document Server

    Toenshoff, Hans Kurt

    2013-01-01

    Manufacturing is the basic industrial activity generating real value. Cutting and abrasive technologies are the backbone of precision production in machine, automotive and aircraft building as well as of production of consumer goods. We present the knowledge of modern manufacturing in these technologies on the basis of scientific research. The theory of cutting and abrasive processes and the knowledge about their application in industrial practice are a prerequisite for the studies of manufacturing science and an important part of the curriculum of the master study in German mechanical engineering. The basis of this book is our lecture “Basics of cutting and abrasive processes” (4 semester hours/3 credit hours) at the Leibniz University Hannover, which we offer to the diploma and master students specializing in manufacturing science.

  4. Experimental analysis of cut welding in aluminium

    DEFF Research Database (Denmark)

    Dorph, Pernille; De Chiffre, Leonardo; Bay, Niels

    1993-01-01

    Cut welding is a newly developed cold pressure welding process. In the present work, an experimental investigation was carried out analyzing the mechanisms involved in cut welding of a block to a strip. Experiments were carried out in technically pure aluminium. The investigation has involved...... tensile testing and metallographic investigations of the welds. The results show that this variant of cut welding is a very reproducible process giving a weld strength equal to 30-40% the strength of the parent material. The experiments have shown that the reason for this relatively low strength...... is an uneven pressure distribution along the weld due to a wave formed during sliding. Attempts to alter the material flow during sliding are presented....

  5. Cutting: unraveling the mystery behind the marks.

    Science.gov (United States)

    Hart, Beverly G

    2007-04-01

    Self-mutilation or cutting is not uncommon and may be detected in the workplace. It stems from an underlying psychological illness, specifically borderline personality disorder (BPD). Individuals diagnosed with BPD are usually attempting to handle negative childhood experiences and feelings of abandonment. They often overreact to social stress and engage in cutting to alleviate uncomfortable feelings. A small percentage go on to attempt suicide. Dialectical behavior therapy (DBT) is the preferred treatment modality for individuals with BPD. Occupational health nurses are in a pivotal position to identify workers who cut and to refer them to appropriate treatment options. In addition, occupational health nurses can learn to reinforce the social skills learned in DBT.

  6. Metal Cutting for Large Component Removal

    International Nuclear Information System (INIS)

    Hulick, Robert M.

    2008-01-01

    Decommissioning of commercial nuclear power plants presents technological challenges. One major challenge is the removal of large components mainly consisting of the reactor vessel, steam generators and pressurizer. In order to remove and package these large components nozzles must be cut from the reactor vessel to precise tolerances. In some cases steam generators must be segmented for size and weight reduction. One innovative technology that has been used successfully at several commercial nuclear plant decommissioning is diamond wire sawing. Diamond wire sawing is performed by rotating a cable with diamond segments attached using a flywheel approximately 24 inches in diameter driven remotely by a hydraulic pump. Tension is provided using a gear rack drive which also takes up the slack in the wire. The wire is guided through the use of pulleys keeps the wire in a precise location. The diamond wire consists of 1/4 inch aircraft cable with diamond beads strung over the cable separated by springs and brass crimps. Standard wire contains 40 diamond beads per meter and can be made to any length. Cooling the wire and controlling the spread of contamination presents significant challenges. Under normal circumstances the wire is cooled and the cutting kerf cleaned by using water. In some cases of reactor nozzle cuts the use of water is prohibited because it cannot be controlled. This challenge was solved by using liquid Carbon Dioxide as the cooling agent. The liquid CO 2 is passed through a special nozzle which atomizes the liquid into snowflakes which is introduced under pressure to the wire. The snowflakes attach to the wire keeping it cool and to the metal shavings. As the CO 2 and metal shavings are released from the wire due to its fast rotation, the snowflakes evaporate leaving only the fine metal shavings as waste. Secondary waste produced is simply the small volume of fine metal shavings removed from the cut surface. Diamond wire sawing using CO 2 cooling has

  7. Flow stress model in metal cutting

    Science.gov (United States)

    Black, J. T.

    1978-01-01

    A model for the plastic deformation that occurs in metal cutting, based on dislocation mechanics, is presented. The model explains the fundamental deformation structure that develops during machining and is based on the well known Cottrell-Stokes Law, wherein the flow stress is partitioned into two parts; an athermal part which occurs in the shear fronts (or shear bands); and a thermal part which occurs in the lamella regions. The deformation envokes the presence of a cellular dislocation distribution which always exists in the material ahead of the shear process. This 'alien' dislocation distribution either exists in the metal prior to cutting or is produced by the compressive stress field which operates in front of the shear process. The magnitude of the flow stress and direction of the shear are shown to be correlated to the stacking fault energy of the metal being cut. The model is tested with respect to energy consumption rates and found to be consistent with observed values.

  8. Laser cutting of concretes with various ballasts

    International Nuclear Information System (INIS)

    Hamasaki, Masanobu; Katsumura, Munehide; Utsumi, Hiroaki

    1985-01-01

    The biological shield concrete and the radiation shield concrete which construct a part of the atomic reactor must be demolished with the decommissioning of the atomic reactor plants. In a case, the demolition using a laser is expected as one of excellent method for the decommissioning of these radioactive concretes. The fundamental cuttings of a mortar, the concretes with andesite, lime stone and gray wacke as ballast and a concrete reinforced with mild steel rods were therefore carried out using a 5 kW output CO 2 laser. As the results of experiment, it was cleared that cutting results varied with ballasts, 100 mm thick reinforced concrete could be cut, safety was high because few dross and few fume were produced. (author)

  9. ENVIRONMENTALLY REDUCING OF COOLANTS IN METAL CUTTING

    Directory of Open Access Journals (Sweden)

    Veijo KAUPPINEN

    2012-11-01

    Full Text Available Strained environment is a global problem. In metal industries the use of coolant has become more problematic in terms of both employee health and environmental pollution. It is said that the use of coolant forms approximately 8 - 16 % of the total production costs.The traditional methods that use coolants are now obviously becoming obsolete. Hence, it is clear that using a dry cutting system has great implications for resource preservation and waste reduction. For this purpose, a new cooling system is designed for dry cutting. This paper presents the new eco-friendly cooling innovation and the benefits gained by using this method. The new cooling system relies on a unit for ionising ejected air. In order to compare the performance of using this system, cutting experiments were carried out. A series of tests were performed on a horizontal turning machine and on a horizontal machining centre.

  10. Robust Design Based Optimisation of Waterjet Cutting

    Directory of Open Access Journals (Sweden)

    Deaconescu Tudor

    2016-01-01

    Full Text Available The most important input quantities of waterjet cutting are the jet pressure, feed speed, stand-off distance, abrasive graining, mass flow, etc. Other quantities contributing to machining efficiency are the type of utilized abrasive or the tilt of the jet. Each of these quantities can be assigned different set points. The roughness of the machined surfaces and the thickness of the cut part are output quantities of the system, their values depending on the input parameters and the influence of various disturbing factors (noises. The paper discusses surface roughness obtained consequently to abrasive jet cutting. Optimisation of the machining system was achieved by intervening on five selected input quantities (factors, with two set points considered for each. Upon applying Taguchi methods, eventually the combination of factor set points was determined that ensures robust behaviour of the system.

  11. Dispersion analysis of arbitrarily cut orthorhombic crystals.

    Science.gov (United States)

    Höfer, Sonja; Ivanovski, Vladimir; Uecker, Reinhard; Kwasniewski, Albert; Popp, Jürgen; Mayerhöfer, Thomas G

    2017-06-05

    We developed a measurement and evaluation scheme to perform dispersion analysis on arbitrarily cut orthorhombic crystals based on the schemes developed for triclinic and uniaxial crystals. As byproduct of dispersion analysis the orientations of the crystal axes are found. In contrast to the spectra of arbitrarily cut uniaxial crystals, where the fit routine has to separate two independent principal spectra, the spectra of arbitrarily cut orthorhombic crystals are a combination of three independent spectra and the evaluation scheme gets more complex. Dispersion analysis is exemplary performed on two different crystals, which show different spectral features and different levels of difficulties to evaluate. Neodymium gallate (NdGaO 3 ) has broad overlapping reflections bands while topaz (Al 2 SiO 4 [F, OH] 2 ) has a quite high total number of infrared active bands. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Trim cut machining and surface integrity analysis of Nimonic 80A alloy using wire cut EDM

    Directory of Open Access Journals (Sweden)

    Amitesh Goswami

    2017-02-01

    Full Text Available This present work deals with the features of trim cut wire EDM machining of Nimonic 80A in terms of machining parameters, to predict material removal rate (MRR, surface roughness (Ra, wire wear ratio (WWR and microstructure analysis. Trim cut is performed after rough cut to remove the rough layer deposited after machining due to melting and re-solidification of the eroded metal from workpiece as well as from wire electrode. Taguchi’s design of experiments methodology has been used for planning and designing the experiments. The relative significance of various factors has also been evaluated and analyzed using ANOVA. The results clearly indicate trim cut potential for high surface finish compared to rough cut machining.

  13. ITER lip seal welding and cutting developments

    Energy Technology Data Exchange (ETDEWEB)

    Levesy, B.; Cordier, J.J.; Jokinen, T. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kujanpää, V.; Karhu, M. [VTT Technical Research Centre of Finland (Finland); Le Barbier, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Määttä, T. [VTT Technical Research Centre of Finland (Finland); Martins, J.P.; Utin, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2015-10-15

    Highlights: • Different TIG and Laser welding techniques are tested. • Twin spot laser welding techniques is the best. • Limited heat input gives a stable weld pool in all positions. • Penetrations is achieved. • Lip seal welding and cutting with a robotic arm is successfully performed on a representative mock-up. - Abstract: The welded lip seals form part of the torus primary vacuum boundary in between the port plugs and the vacuum vessel, and are classified as Protection Important Component. In order to refurbish the port plugs or the in-vessel components, port plugs have to be removed from the machine. The lip seal design must enable up to ten opening of the vacuum vessel during the life time operation of the ITER machine. Therefore proven, remote reliable cutting and re-welding are essential, as these operations need to be performed in the port cells in a nuclear environment, where human presence will be restricted. Moreover, the combination of size of the components to be welded (∼10 m long vacuum compatible thin welds) and the congested environment close to the core of the machine constraint the type and size of tools to be used. This paper describes the lip seal cutting and welding development programme performed at the VTT Technical Research Centre, Finland. Potential cutting and welding techniques are analyzed and compared. The development of the cutting, TIG and laser welding techniques on samples are presented. Effects of lip seal misalignments and optimization of the 2 welding processes are discussed. Finally, the manufacturing and test of the two 1.2 m × 1 m representative mock-ups are presented. The set-up and use of a robotic arm for the mock-up cutting and welding operations are also described.

  14. A framework for cut-over management

    Directory of Open Access Journals (Sweden)

    Guido Nageldinger

    2015-11-01

    Full Text Available The purpose of this paper is to provide a governance structure for IT-related projects in order to assure a safeguarded and timely transition to a productive environment. This transitioning, which rarely exceeds a weekend, is colloquially called ‘cut-over’, ‘rollout’ or ‘deployment’. The governance structure is defined in accordance with a set of project-specific deliverables for a cascade-type procedural project-management model, which is integrated within an Information Technology Infrastructure Library (ITIL-orientated service organization. This integration is illustrated by the use of a semi-agile release model. Due to the release model selected, which is particularly characterized by its bundling of projects for a release-specific rollout (as it is referred to in the project documentation, a new definition and interpretation of deployment from a generic ITIL perspective is required. The facilitated release model requires a distinction between a project-specific cut-over and a release-specific rollout. This separation gives rise to two types of go-live scenarios: one for each participating project and one for each release. Additionally, an interplay between cut-over planning for a project and rollout planning for a release becomes apparent. Projects should already incorporate cut-over related deliverables in the initial planning phase. Even though consulting methodologies such as ASAP (Accelerated SAP, recommend scattered, project-specific deliverables useful for cut-over planning, this publication offers an integrated approach on how to prepare systematically for a project-specific cut-over with all required deliverables. The framework provided maps out ITIL’s release and deployment process by means of IT projects; furthermore it allows IT projects to interface easily with the ITIL change-management process.

  15. Stability analysis of multipoint tool equipped with metal cutting ceramics

    Science.gov (United States)

    Maksarov, V. V.; Khalimonenko, A. D.; Matrenichev, K. G.

    2017-10-01

    The article highlights the issues of determining the stability of the cutting process by a multipoint cutting tool equipped with cutting ceramics. There were some recommendations offered on the choice of parameters of replaceable cutting ceramic plates for milling based of the conducted researches. Ceramic plates for milling are proposed to be selected on the basis of value of their electrical volume resistivity.

  16. Shoot multiplication of Paphiopedilum orchid through in vitro cutting ...

    African Journals Online (AJOL)

    In this study, the effect of in vitro cutting methods and medium composition on efficient shoot multiplication of Paphiopedilum Hsinying Rubyweb was investigated. Among three different in vitro stem cutting methods used, vertical cutting was able to produce more new shoots than horizontal and cross cutting when cultured on ...

  17. Material testing of copper by extrusion-cutting

    DEFF Research Database (Denmark)

    Segalina, F.; De Chiffre, Leonardo

    2017-01-01

    was developed and implemented on a CNC lathe. An investigation was carried out extrusion-cutting copper discs using high-speed-steel cutting tools at 100 m/min cutting speed. Flow stress values for copper under machining-relevant conditions were obtained from measurement of the extrusion-cutting force...

  18. Modified atmosphere packaging for fresh-cut fruits and vegetables

    Science.gov (United States)

    The latest development in and different aspects of modified atmosphere packaging for fresh-cut fruits and vegetables are reviewed in the book. This book provides all readers, including fresh-cut academic researchers, fresh-cut R&D personnel, and fresh-cut processing engineers, with unique, essential...

  19. Influence of cutting conditions on chip side curl

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo

    2004-01-01

    The paper describes the influence of local variations of contact length, cutting speed and material constraint, showing the effect of lubrication, on the side curl of the chip. The following examples are illustrated by experiments: cutting of a tube vs. cutting of a bar; cutting using a tool...

  20. 49 CFR 213.352 - Torch cut rail.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  1. 7 CFR 58.413 - Cutting and packaging rooms.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cutting and packaging rooms. 58.413 Section 58.413....413 Cutting and packaging rooms. When small packages of cheese are cut and wrapped, separate rooms... outward to minimize the entrance of unfiltered air into the cutting and packaging room. The waste...

  2. Recent results in mirror based high power laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Nielsen, Jakob Skov; Elvang, Mads

    2004-01-01

    In this paper, recent results in high power laser cutting, obtained in reseach and development projects are presented. Two types of mirror based focussing systems for laser cutting have been developed and applied in laser cutting studies on CO2-lasers up to 12 kW. In shipyard environment cutting...

  3. 21 CFR 882.4275 - Dowel cutting instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dowel cutting instrument. 882.4275 Section 882...) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4275 Dowel cutting instrument. (a) Identification. A dowel cutting instrument is a device used to cut dowels of bone for bone grafting. (b...

  4. Development of underwater laser cutting technique for steel and ...

    Indian Academy of Sciences (India)

    metal vapour from the cut kerf is spread in air. In cutting of irradiated material, debris and metal vapour creates airborne activity, which may be harmful for people working nearby, whereas, underwater cutting is advantageous in terms of a narrow. HAZ adjacent to the laser cut surface providing better samples for the analysis.

  5. A sharp cutting liposuction cannula for gynecomastia.

    Science.gov (United States)

    Hamas, R S; Williams, C W

    1998-01-01

    Liposuction is often used for the treatment of gynecomastia. Blunt liposuction cannulas can remove the fat but are not very effective in fibrous breast tissue, which requires open excision. Ultrasound-assisted lipoplasty has been advocated for gynecomastia because it effectively removes the fat from fibrous areas. An alternative treatment is a sharp cutting liposuction cannula that easily penetrates and removes the fibrous breast tissue along with the fatty component. The early experience of 22 surgeons who used this cannula in 88 cases of gynecomastia is reported. For 19 of the 22 surgeons, liposuction with sharp cutting cannulas alone gave a satisfactory result in 81% of their patients.

  6. Cut Locus Construction using Deformable Simplicial Complexes

    DEFF Research Database (Denmark)

    Misztal, Marek Krzysztof; Bærentzen, Jakob Andreas; Anton, François

    2011-01-01

    In this paper we present a method for appproximating cut loci for a given point p on Riemannian 2D manifolds, closely related to the notion of Voronoi diagrams. Our method finds the cut locus by advecting a front of points equally distant from p along the geodesics originating at p and finding...... the lines of self-intersections of the front in the parametric space. This becomes possible by using the deformable simplicial complexes (DSC, [1]) method for deformable interface tracking. DSC provide a simple collision detection mechanism, allows for interface topology control, and does not require...

  7. Designing for hot-blade cutting

    DEFF Research Database (Denmark)

    Brander, David; Bærentzen, Jakob Andreas; Clausen, Kenn

    2016-01-01

    by authors of the paper, which facilitates high-speed production of doubly-curved foam moulds. Complementary to design rationalisation, in which arbitrary surfaces are translated to hot-blade-cuttable geometries, the presented method enables architects and designers to design directly with the non......-trivial constraints of blade-cutting in a bottom-up fashion, enabling an exploration of the unique architectural potential of this fabrication approach. The method is implemented as prototype design tools in MatLAB, C++, GhPython, and Python and demonstrated through cutting of expanded polystyrene foam design...

  8. On Non-Abelian Symplectic Cutting

    DEFF Research Database (Denmark)

    Martens, Johan; Thaddeus, Michael

    2012-01-01

    We discuss symplectic cutting for Hamiltonian actions of non-Abelian compact groups. By using a degeneration based on the Vinberg monoid we give, in good cases, a global quotient description of a surgery construction introduced by Woodward and Meinrenken, and show it can be interpreted in algebro......-geometric terms. A key ingredient is the `universal cut' of the cotangent bundle of the group itself, which is identified with a moduli space of framed bundles on chains of projective lines recently introduced by the authors....

  9. On the Cutting Performance of Segmented Diamond Blades when Dry-Cutting Concrete.

    Science.gov (United States)

    Sánchez Egea, A J; Martynenko, V; Martínez Krahmer, D; López de Lacalle, L N; Benítez, A; Genovese, G

    2018-02-09

    The objective of the present study is to analyze and compare the cutting performance of segmented diamond blades when dry-cutting concrete. A cutting criteria is proposed to characterize the wear of the blades by measuring the variation of the external diameter and the weight loss of the blade. The results exhibit the cutting blade SB-A, which has twice the density of diamonds and large contact area, exhibits less wear even though the material removal rate is higher compared with the other two cutting blades. Additionally, the surface topography of the different blades is evaluated to examine the impact of wear depending on the surface profile and the distribution of the diamonds in the blade's matrix. Large number of diamonds pull-out are found in blades type SB-C, which additionally shows the worst wear resistant capability. As a conclusion, the cutting efficiency of the blade is found to be related to the density of embedded diamonds and the type of the surface profile of the cutting blade after reaching the stop criteria.

  10. Status on underwater plasma arc cutting in KHI, 3

    International Nuclear Information System (INIS)

    Abe, Tadashi; Aota, Toshiichi; Nishizaki, Tadashi; Nakayama, Shigeru; Yamashita, Seiji

    1983-01-01

    In Kawasaki Heavy Industries, Ltd., the development of a remote dismantling system by underwater plasma arc cutting process has been advanced, expecting its application to the dismantling and removal of nuclear reactor facilities. In the previous two reports, the fundamental experimental results such as the comparison of the cutting capability in air and in water were shown, but this time, the remote automatic cutting of wedge-shaped specimens was carried out, using a newly installed manipulator for underwater works, therefore its outline is reported. Also the cutting experiment by overhead position and vertical position was performed by using the same equipment, and comparison was made with the cutting capability by downhand and horizontal positions. It is important to grasp the cutting characteristics in the case of upward advancing and downward advancing cuttings by overhead and vertical positions when the cutting of pressure vessels and horizontal pipes into rings is supposed. The experimental apparatus, the cutting conditions, the testing method and the test results of the cutting capability test, the test of changing direction during cutting, and the remote cutting of pipes into rings are described. The underwater plasma arc cutting can cut all metals, the cutting speed is relatively high, and the apparatus is simple and compact. (Kako, I.)

  11. Hot Blade Cuttings for the Building Industries

    DEFF Research Database (Denmark)

    Brander, David; Bærentzen, Jakob Andreas; Evgrafov, Anton

    2016-01-01

    . The project aims to reduce the amount of manual labour as well as production time by applying robots to cut expanded polystyrene (EPS) moulds for the concrete to form doubly curved surfaces. The scheme is based upon the so-called Hot Wire or Hot Blade technology where the surfaces are essentially swept out...

  12. Optimal Wafer Cutting in Shuttle Layout Problems

    DEFF Research Database (Denmark)

    Nisted, Lasse; Pisinger, David; Altman, Avri

    2011-01-01

    . The shuttle layout problem is frequently solved in two phases: first, a floorplan of the shuttle is generated. Then, a cutting plan is found which minimizes the overall number of wafers needed to satisfy the demand of each die type. Since some die types require special production technologies, only compatible...

  13. The size effect in metal cutting

    Indian Academy of Sciences (India)

    When discontinuous microcracks form on the shear plane they weld and reform as strain proceeds, thus joining the transport of dislocations in accounting for the total slip of the shear plane. In the presence of a contaminant, such as CCl4 vapour at a low cutting speed, the rewelding of microcracks decreases, resulting in ...

  14. A Dictatorship Theorem for Cake Cutting

    DEFF Research Database (Denmark)

    Branzei, Simina; Miltersen, Peter Bro

    2015-01-01

    We consider discrete protocols for the classical Steinhaus cake cutting problem. Under mild technical conditions, we show that any deterministic strategy-proof protocol in the standard Robertson-Webb query model is dictatorial, that is, there is a fixed agent to which the protocol allocates the e...

  15. Female Genital Cutting in Contemporary Eritrea: Determinants ...

    African Journals Online (AJOL)

    Abstract. The observation that about 90% of Eritrean women were circumcised in 2002 increased interest to understand the trends, determinants, and consequences of female genital cutting (FGC). The study used data from the 2002 EDHS and the 2003 Female Genital Mutilation Survey to consider factors that influence the ...

  16. Regge cuts in γγ scattering

    International Nuclear Information System (INIS)

    Jackson, C.P.

    1976-01-01

    It is shown that the Pomeron-Pomeron cut in γγ scattering has natural C parity and conspires, in contrast to the Pomeron pole which is evasive, and has natural parity and C parity. The constraints this places upon the invariant amplitudes are analyzed

  17. Cern faces 260m euro budget cuts

    CERN Multimedia

    Banks, Michael

    2010-01-01

    "The Cern particle-physics lab near Geneva is to slash about 260m euro ($340m) from its budget for 2011-2015. The cut, which was approved by Cern's council last month, will require the lab to scale back research into future particles accelerators" (0.5 page)

  18. Indirect Revelation Mechanisms for Cake Cutting

    DEFF Research Database (Denmark)

    Branzei, Simina; Miltersen, Peter Bro

    We consider discrete protocols for the classical Steinhaus cake cutting problem. Under mild technical conditions, we show that any deterministic strategy-proof protocol in the standard Robertson-Webb query model is dictatorial, that is, there is a fixed agent to which the protocol allocates...

  19. The cutting of metals via plastic buckling.

    Science.gov (United States)

    Udupa, Anirudh; Viswanathan, Koushik; Ho, Yeung; Chandrasekar, Srinivasan

    2017-06-01

    The cutting of metals has long been described as occurring by laminar plastic flow. Here we show that for metals with large strain-hardening capacity, laminar flow mode is unstable and cutting instead occurs by plastic buckling of a thin surface layer. High speed in situ imaging confirms that the buckling results in a small bump on the surface which then evolves into a fold of large amplitude by rotation and stretching. The repeated occurrence of buckling and folding manifests itself at the mesoscopic scale as a new flow mode with significant vortex-like components-sinuous flow. The buckling model is validated by phenomenological observations of flow at the continuum level and microstructural characteristics of grain deformation and measurements of the folding. In addition to predicting the conditions for surface buckling, the model suggests various geometric flow control strategies that can be effectively implemented to promote laminar flow, and suppress sinuous flow in cutting, with implications for industrial manufacturing processes. The observations impinge on the foundations of metal cutting by pointing to the key role of stability of laminar flow in determining the mechanism of material removal, and the need to re-examine long-held notions of large strain deformation at surfaces.

  20. Cutting work in thick section cryomicrotomy.

    Science.gov (United States)

    Saubermann, A J; Riley, W D; Beeuwkes, R

    1977-09-01

    The forces during cryosectioning were measured using miniature strain gauges attached to a load cell fitted to the drive arm of the Porter-Blum MT-2 cryomicrotome. Work was calculated and the data normalized to a standard (1 mm X 1 mm X 0.5 micrometer) section. Thermal energy generated was also calculated. Five parameters were studied: cutting angle, thickness, temperature, hardness, and block shape. Force patterns could be divided into three major groups thought to represent cutting (Type I), large fracture planes greater than 10 micrometer in length (Type II), and small fracture planes less than 10 micrometer in length (Type III). Type I and Type II produced satisfactory sections. Work in cutting ranged from an average of 78.4 muJ to 568.8 muJ. Cutting angle and temperature had the greatest effect on sectioning. Heat generated would be sufficient to cause through-section melting for 0.5 micrometer thick sections assuming the worst possible case, namely that all heat went into the section without loss. Presence of a Type II pattern (large fracture pattern) is thought to be presumptive evidence against thawing.

  1. Automatic Generation of Minimal Cut Sets

    Directory of Open Access Journals (Sweden)

    Sentot Kromodimoeljo

    2015-06-01

    Full Text Available A cut set is a collection of component failure modes that could lead to a system failure. Cut Set Analysis (CSA is applied to critical systems to identify and rank system vulnerabilities at design time. Model checking tools have been used to automate the generation of minimal cut sets but are generally based on checking reachability of system failure states. This paper describes a new approach to CSA using a Linear Temporal Logic (LTL model checker called BT Analyser that supports the generation of multiple counterexamples. The approach enables a broader class of system failures to be analysed, by generalising from failure state formulae to failure behaviours expressed in LTL. The traditional approach to CSA using model checking requires the model or system failure to be modified, usually by hand, to eliminate already-discovered cut sets, and the model checker to be rerun, at each step. By contrast, the new approach works incrementally and fully automatically, thereby removing the tedious and error-prone manual process and resulting in significantly reduced computation time. This in turn enables larger models to be checked. Two different strategies for using BT Analyser for CSA are presented. There is generally no single best strategy for model checking: their relative efficiency depends on the model and property being analysed. Comparative results are given for the A320 hydraulics case study in the Behavior Tree modelling language.

  2. Optimisation of the Laser Cutting Process

    DEFF Research Database (Denmark)

    Dragsted, Birgitte; Olsen, Flemmming Ove

    1996-01-01

    The problem in optimising the laser cutting process is outlined. Basic optimisation criteria and principles for adapting an optimisation method, the simplex method, are presented. The results of implementing a response function in the optimisation are discussed with respect to the quality as well...

  3. Evaluation of alternative snow plow cutting edges.

    Science.gov (United States)

    2009-05-01

    With approximately 450 snow plow trucks, the Maine Department of Transportation (MaineDOT) uses in : excess of 10,000 linear feet of plow cutting edges each winter season. Using the 2008-2009 cost per linear : foot of $48.32, the Departments total co...

  4. Cuts of Feynman Integrals in Baikov representation

    International Nuclear Information System (INIS)

    Frellesvig, Hjalte; Papadopoulos, Costas G.

    2017-01-01

    Based on the Baikov representation, we present a systematic approach to compute cuts of Feynman Integrals, appropriately defined in d dimensions. The information provided by these computations may be used to determine the class of functions needed to analytically express the full integrals.

  5. Vase Life of Alstereomeria Cut Flowers

    African Journals Online (AJOL)

    Effects of Plant Growth Regulators on Postharvest Quality and. Vase Life of Alstereomeria Cut Flowers. Emongor*, V.E., T.M. Mutui and M.l .. Hutchinson. Department of Crop Science. University of Nairobi, P.O.BOX 29053, Nairobi, Kenya. Abstract. The objective of the experiment was to investigate the response of ...

  6. Science Funding cuts threaten scientific research

    CERN Multimedia

    2008-01-01

    Page 1 of 3 Researchers are in uproar after a recently established quango unveiled a series of cuts and abandoned some projects altogether because of an estimated 80m funding shortfall. Martin Rees, the Astronomer Royal, argues that Britain will pay a far higher price if it scraps vital projects now

  7. Rooting experiments with cuttings of Salix caprea

    Energy Technology Data Exchange (ETDEWEB)

    Ericsson, T.

    1981-01-01

    The ability of the following external factors on inducing root formation on leafless cuttings of Salix caprea L. was investigated: root promoting hormones, centrifugation, diffusate (plant sap), and planting substrates. The greatest number of rooted Salix caprea cuttings was obtained after treatment with 40 ppM IBA during 24 hours. However, the young root systems were very susceptile to fungal infections. Thus, the initial positive effect of the root promoting hormone was neutralized by the low survival among the test plants. Neither centrifugation nor diffusate treatment of the cuttings increased the rooting percentage further. Hormone treatment of young shoots or buds grown in water resulted in vigorous root formation on all stem sections placed below the water surface. Practically all vegetative buds on each sprout gave rise to new plants. Planting in coarse sand (3 mm) resulted in healthier plants and stronger root systems compared with cuttings rooted in peat-sand mixture (75/25 vol %), agar, and fine grained sand. Roots developed in coarse sand were spread along a longer stem section compared with roots formed in a compact substrat. Plants with a despersed root system tended to be less harmed by fungal infections than plants with all roots concentrated at the base. It is concluded that the main problem associated with vegetative propagation of Salix caprea, in the traditional manner, is the susceptibility of the hormontreated cuttings against fungal infections and not the root formations step in it self. Hormone treatment of young shoots or buds is proposed as one conceivable solution on this problem.

  8. Environments for rooting of guava trees multiplied by softwood cuttings or mini-cuttings

    Directory of Open Access Journals (Sweden)

    Leonardo Muniz Aziz Milhem

    2015-05-01

    Full Text Available The goal of this study was to evaluate highmoisture saturation environments for rootingcuttings from guava. The experiment was carriedout in randomized complete block design infactorial scheme composed by guava tree cultivars(Paluma and Cortibel 6, types of cuttings(softwood cuttings and minicuttings, androoting environments (conventional chamberwith intermittent nebulization and minichambers constituted of plastic containers. Fourrepetitions were used and the experimental plotswere composed by ten softwood cuttings or minicuttings.Rooting of ‘Paluma’ ranged between77.5 and 97.5 % and of ‘Cortibel 6’ between2.5 and 57.5%, depending on the environmentand the propagation technique.

  9. Experimental Investigation on Cutting Characteristics in Nanometric Plunge-Cutting of BK7 and Fused Silica Glasses.

    Science.gov (United States)

    An, Qinglong; Ming, Weiwei; Chen, Ming

    2015-03-27

    Ductile cutting are most widely used in fabricating high-quality optical glass components to achieve crack-free surfaces. For ultra-precision machining of brittle glass materials, critical undeformed chip thickness (CUCT) commonly plays a pivotal role in determining the transition point from ductile cutting to brittle cutting. In this research, cutting characteristics in nanometric cutting of BK7 and fused silica glasses, including machined surface morphology, surface roughness, cutting force and specific cutting energy, were investigated with nanometric plunge-cutting experiments. The same cutting speed of 300 mm/min was used in the experiments with single-crystal diamond tool. CUCT was determined according to the mentioned cutting characteristics. The results revealed that 320 nm was found as the CUCT in BK7 cutting and 50 nm was determined as the size effect of undeformed chip thickness. A high-quality machined surface could be obtained with the undeformed chip thickness between 50 and 320 nm at ductile cutting stage. Moreover, no CUCT was identified in fused silica cutting with the current cutting conditions, and brittle-fracture mechanism was confirmed as the predominant chip-separation mode throughout the nanometric cutting operation.

  10. Test tube systems with cutting/recombination operations

    Energy Technology Data Exchange (ETDEWEB)

    Freund, R. [Technische Universitaet Wien (Austria); Csuhaj-Varju, E. [Computer and Automation Institute, Budapest (Hungary); Wachtler, F. [Universitaet Wien (Austria)

    1996-12-31

    We introduce test tube systems based on operations that are closely related to the splicing operations, i.e. we consider the operations of cutting a string at a specific site into two pieces with marking them at the cut ends and of recombining two strings with specifically marked endings. Whereas in the splicing of two strings these strings are cut at specific sites and the cut pieces are recombined immediately in a crosswise way, in CR(cutting/recombination)-schemes cutting can happen independently from recombining the cut pieces. Test tube systems based on these operations of cutting and recombination turn out to have maximal generative power even if only very restricted types of input filters for the test tubes are used for the redistribution of the contents of the test tubes after a period of cuttings and recombinations in the test tubes. 10 refs.

  11. Comparison of CO2 Laser Cutting with Different Laser Sources

    DEFF Research Database (Denmark)

    Ketting, Hans-Ole; Olsen, Flemmming Ove

    1996-01-01

    This paper contains CO2 laser cutting results in mild and stainless steel with different laser sources. The main factors which affect the cutting speed and quality are the power, the cutting gas and focal point conditions. Keeping the power and cutting gas constant, the focal point conditions have...... is proven at least for oxyfuel cutting of mild steel, whereas fusion cutting of stainless steel is more complicated.Cutting results from 7 different indus-trial laser sources connected to different moving systems, were used to get information about the importance of the Beam Quality Number K and focal spot...... size,for the maximum cutting speed. One of the 7 laser sources with different focal length and thus different minimum spot size, was then used to investigate more in details the importance of the focal spot size cutting stainless steel with high pressure nitrogen. It looks as if there is a strong...

  12. Commissioning a hobby cutting device for radiochromic film preparation.

    Science.gov (United States)

    Zolfaghari, Somayeh; Francis, Kirby E; Kairn, Tanya; Crowe, Scott B

    2017-06-01

    In addition to a high spatial resolution and well characterised dose response, one of the major advantages of radiochromic film as a dosimeter is that sheets of film can be cut into pieces suitable for use as calibration films, and for in vivo and phantom measurements. The cutting of film is typically done using scissors or a guillotine, and this process can be time-consuming, limited in precision, requires extensive handling and does not allow holes to be cut from the film without cutting from an existing edge. This study investigated the use of a Brother ScanNCut hobby cutting system for EBT3 film preparation. The optimal operating parameters (blade size, pressure, speed) that resulted in precise cuts with minimal delamination at cut edges were identified using test cutting patterns. These parameters were then used to cut a large film insert for a stereotactic head phantom for comparison against an insert cut with scissors. While the hobby cutting system caused a wider region of delamination at the film edge (1.8 mm) compared to scissors (1 mm), the hobby cutting system was found to be able to produce reproducible cuts more efficiently and more accurately than scissors. The use of the hobby cutting system is recommended for complex phantom inserts (containing sharp corners or holes for alignment rods) or in situations where large numbers of film pieces need to be prepared.

  13. Identification of cutC and cutF (nlpE) genes involved in copper tolerance in Escherichia coli.

    Science.gov (United States)

    Gupta, S D; Lee, B T; Camakaris, J; Wu, H C

    1995-08-01

    It has been suggested previously that copper transport in Escherichia coli is mediated by the products of at least six genes, cutA, cutB, cutC, cutD, cutE, and cutF. A mutation in one or more of these genes results in an increased copper sensitivity (D. Rouch, J. Camakaris, and B. T. O. Lee, p. 469-477, in D. H. Hamer and D. R. Winge, ed., Metal Ion Homeostasis: Molecular Biology and Chemistry, 1989). Copper-sensitive cutC and cutF mutants were transformed with a genomic library of E. coli, and copper-tolerant transformants were selected. Two distinct clones were identified, each of which partially restores copper tolerance in both the cutC and cutF mutants of E. coli. Subcloning, physical mapping, and sequence analysis have revealed that the cutC gene is located at 42.15 min on the E. coli genome and encodes a cytoplasmic protein of 146 amino acids and that the cutF gene is located at 4.77 min on the E. coli genome and is allelic to the nlpE gene independently identified by Silhavy and coworkers (W. B. Snyder, L. J. B. Davis, P. N. Danese, C. L. Cosma, and T. J. Silhavy, J. Bacteriol. 177:4216-4223, 1995). Results from the genetic mapping of the copper-sensitive mutations in the cutF mutant and sequencing of the cutC and cutF (nlpE) alleles from both cutC and cutF mutants indicate that both the cutC and cutF mutants are in fact double mutants altered in these two genes, and mutations in both the genes appear to be required for the copper-sensitive phenotype in each mutant.

  14. Tenderness charactherization of ostrich meat commercial cuts

    Directory of Open Access Journals (Sweden)

    Janaina Conte Hadlich

    2012-12-01

    Full Text Available The ostrich meat has become an interesting source of protein as well as being an alternative to red meat, because of its healthy fatty acid profile, with a high content of polyunsaturated fatty acids and low content of intramuscular fat, which arouses the interest of people who want a low animal fat diet. Ostrich meat is also appreciated by the tenderness, since it is one of the larger impact characteristics on the acceptance of a meat product for consumers. The aim of this study was to evaluate the tenderness of different ostrich meat commercial cuts and certificate that all studied cuts present tenderness acceptable by consumers. The laboratory tests were performed at the Laboratory of Biochemistry of Proteins (FMVZ, being measured shear force of seven commercial cuts of ostrich meat. The cuts were: internal thigh, external thigh, filet plan, filet out, filet small, rump and filet fan. The samples were boiled in water bath controlled by time and temperature. After chilling, fragments of 1.0 x 1.0 x 3.0 cm were removed from samples. Shear force measurements were performed using a mechanical Warner-Bratzler Shear Force equipment. The shear force means were: internal thigh (3.5 kg, external thigh (2.8 kg, filet plan (2.4 kg, filet out (1.6 kg, filet small (3.5 kg, rump (3.3 kg and filet fan (2.0 kg. All the commercial cuts evaluated had very low values of shear force, denoting meat extremely tender. The classification of meat tenderness is based on shear force values, being values below 4.6 kg considered meat with desirable tenderness. All ostrich meat commercial cuts analyzed had shear force values lower than 4.6 kg, being classified as meat of extreme tenderness. The results found in this work allow concluding that ostrich meat can be considered tender. These findings lead us to consider the ostrich meat as an interesting alternative to red meat, in relation to tenderness and healthy fatty acid profile, being favorable for people suffering from

  15. Respiration rate and ethylene production of fresh cut lettuce as affected by cutting grade

    Directory of Open Access Journals (Sweden)

    J. MARTÍNEZ

    2008-12-01

    Full Text Available For designing optimal polymeric films for modified atmosphere packaging of whole heads as well as for minimally fresh processed (fresh-cut Iceberg lettuce ‘Coolguard’, the effect of several cutting grades on respiration rate (RR and ethylene production at 5ºC was studied. According to common industrial practices cutting grades less than 0.5 cm, between 0.5 and 1 cm, and 2 cm length were selected. Results from four experiments were compared to those obtained for whole heads in which a homogenous range of 6 to 8 ml CO2 kg-1 h-1 in RR was found. Compared to whole heads, in fresh-cut lettuce the RR was 2-fold higher. The lowest cutting grade showed the highest respiration rate, and no significant differences in RR among lettuce pieces of intermediate and the highest grades were found. No ethylene production was detected in whole heads, while in minimally processed lettuce pieces only traces were found. For avoiding risks of anaerobic respiration and excessive CO2 levels within packages containing fresh-cut lettuce pieces lower than 0.5 cm length, films with relatively high O2 permeability like standard polypropylene or low-density polyethylene must be selected.;

  16. ANALYSIS OF CUTTING FORCES ON CNC LATHES EXPERIMENTAL APPROACH

    Directory of Open Access Journals (Sweden)

    Erdem Koç

    1996-01-01

    Full Text Available Objective of this study is to make use easy programming of CNC lathes and to achieve the optimization of part program prepared considering the limiting parameters of the machine. In the present study, a BOXFORD 250 B CNC lathe has been used for experiment and optimization process. The measurement of cutting forces exerted on the cutting tool of CNC lathe has been performed. The cutting forces occurring during the turning operation have been determined for different depth of" cut, feed rate and cutting speed as well as different cutting tools and related data base has been obtained.

  17. Development of lathe tool dynamometer and finding cutting forces using negative and positive rake angle cutting tool

    International Nuclear Information System (INIS)

    Zeb, M.A.; Irfan, M.A.

    2005-01-01

    Most output parameters in machining, such as cutting forces, temperatures, strains and the work-hardening of the chip material, are directly related to the chip formation process. The characteristics of machining processes can be well understood if the forces and strains during chip formation are known. In this research a lathe tool dynamometer was used to measure cutting forces involved in machining of Steel 1045 and Aluminum 2219 T62. High Speed Steel (HSS), cutting tools with positive and negative rake angles were used. It was observed that more cutting forces are experienced by the cutting tool with positive rake angle as compared to the forces experienced by the cutting tool with negative rake angle. For steel 1045 the cutting forces using positive rake angle cutting tool were much higher. This suggested that for harder materials using a negative rake angle is more suitable for cutting. (author)

  18. Keeping the Lights on While Cutting Costs.

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1998-08-01

    In 1992, the Bonneville Power Administration spent $361 million in capital on a system to transmit electricity. By 1998, it was spending about one-third that amount: $123 million. In 1992, BPA`s expenses for managing, operating and maintaining the transmission system ran $160 million. By 1998, BPA had cut expenses to $128 million. Maintenance costs alone were cut 28%. In 1992, management of the grid was split into six organizations. Today, there is one. About 2,900 people worked for transmission in October 1992. By February 1998, the Transmission Business Line (TBL) employed 1,855. Transmission in 1992 for the most part meant new towers, lines and substations. Today it means computers, digital communications and electronic controls.

  19. Riemannian and Lorentzian flow-cut theorems

    Science.gov (United States)

    Headrick, Matthew; Hubeny, Veronika E.

    2018-05-01

    We prove several geometric theorems using tools from the theory of convex optimization. In the Riemannian setting, we prove the max flow-min cut (MFMC) theorem for boundary regions, applied recently to develop a ‘bit-thread’ interpretation of holographic entanglement entropies. We also prove various properties of the max flow and min cut, including respective nesting properties. In the Lorentzian setting, we prove the analogous MFMC theorem, which states that the volume of a maximal slice equals the flux of a minimal flow, where a flow is defined as a divergenceless timelike vector field with norm at least 1. This theorem includes as a special case a continuum version of Dilworth’s theorem from the theory of partially ordered sets. We include a brief review of the necessary tools from the theory of convex optimization, in particular Lagrangian duality and convex relaxation.

  20. Female genital mutilation/cutting: an update.

    Science.gov (United States)

    Rouzi, A A; Alturki, F

    2015-01-01

    Female genital mutilation/cutting (FGM/C) is a cultural practice involving several types of external female genitalia cutting. FGM/C is known to occur in all parts of the world but is most prevalent in 28 countries in Africa and the Middle East and among immigrant communities in Europe, Australia, New Zealand, Canada, and the United States. Studies of FGM/C suffer from many methodological problems including inadequate analysis and an unclear reporting of results. The evidence to link FGM/C to infertility is weak. The management of epidermal clitoral inclusion cysts includes expensive investigations like comprehensive endocrinology tests and MRI resulting in unnecessary anxiety due to delay in surgical treatment. Similarly, unnecessary cesarean sections or rupture of the infibulation scar continue to occur because of the inadequate use of intrapartum defibulation. A significant amount of efforts is required to improve and correct the inadequate care of FGM/C women and girls.

  1. Cut-constructible part of QCD amplitudes

    International Nuclear Information System (INIS)

    Britto, Ruth; Feng Bo; Mastrolia, Pierpaolo

    2006-01-01

    Unitarity cuts are widely used in analytic computation of loop amplitudes in gauge theories such as QCD. We expand upon the technique introduced in hep-ph/0503132 to carry out any finite unitarity cut integral. This technique naturally separates the contributions of bubble, triangle and box integrals in one-loop amplitudes and is not constrained to any particular helicity configurations. Loop momentum integration is reduced to a sequence of algebraic operations. We discuss the extraction of the residues at higher-order poles. Additionally, we offer concise algebraic formulas for expressing coefficients of three-mass triangle integrals. As an application, we compute all remaining coefficients of bubble and triangle integrals for nonsupersymmetric six-gluon amplitudes

  2. Mounting the cutting mark on the microfiche

    International Nuclear Information System (INIS)

    Koike, Kunio; Habara, Tadashi; Narui, Shigeko

    1979-01-01

    The Japanese National Center of INIS has been submitting MF to the INIS Headquarters since 1971. In 1977, the center was requested to mount a cutting mark on the master MF on the basis of the NMA-MS-5 Standard which had never been adopted in Japan. Its new method was investigated in the collaboration with the microfilming companies. Consequently the best way was found by exposing the light on a spot of the film at photographing. But it took much time to make them in use, therefore, its tentative way was taken by painting the black ink manually on the master fiche. While the microfilming companies made an effort to adapt the camera to put marks other than former one. After bringing to completion, the cutting marks satisfied with the standard came to be automatically mounted on the master fiches. (author)

  3. Researches regarding cutting tool condition monitoring

    Directory of Open Access Journals (Sweden)

    Inţă Marinela

    2017-01-01

    Full Text Available The paper main purpose is monitoring of tool wear in metal cutting using neural networks due to their ability of learning and adapting their self, based on experiments. Monitoring the cutting process is difficult to perform on-line because of the complexity of tool wear process, which is the most important parameter that defines the tool state at a certain moment. Most of the researches appraise the tool wear by indirect factors such as forces, consumed power, vibrations or the surface quality. In this case, it is important to combine many factors for increasing the accuracy of tool wear prediction and establish the admissible size of wear. For this, paper both the theoretical data obtained from FEM analyze and experimental ones are used and compared in order to appreciate the reliability of the results.

  4. Prototype arc saw design and cutting trials

    International Nuclear Information System (INIS)

    Allison, G.S.

    1980-09-01

    A program was initiated to develop the arc saw as a tool capable of removing the end fittings from spent nuclear fuel bundles. A special arc saw for this purpose was designed, installed at the Pacific Northwest Laboratory and satisfactorily operated to remove end fittings from simulated, nonradioactive fuel bundles. The design of the arc saw included consideration of the cutting environment, power supply size, control equipment, and work piece size. Several simulated fuel bundles were cut to demonstrate that the arc saw met design specifications. Although the arc saw development program was curtailed before significant performance data could be collected, tests indicate that the arc saw is a good means of cropping spent fuel bundles and is well suited to remote operation and maintenance

  5. Cutting the cornea with a waterjet keratome.

    Science.gov (United States)

    Lipshitz, I; Bass, R; Loewenstein, A

    1996-01-01

    Waterjet cutting is an advanced technology. It consists of a cutting tool that uses a very thin stream of ultra-high-pressure water forced at high velocity through a very small nozzle, creating a very sharp knife. We report on the first experimental use of waterjet technology to reshape the cornea. The system was used in vitro on 10 bovine eyes, and in vivo on 10 albino rabbit eyes. Using the waterjet keratome (Lipshitz-Bass knife, LBK) lamellar corneal incisions were performed. Histological examinations were performed. A waterjet stream was found to be capable of incising corneas at relatively low energy levels (4000 PSI). Good surface quality could be obtained, and there was no collateral damage to the remaining portion of the cornea, lens, or retina. In the in vivo experiments, the epithelium healed within 48 hours. These preliminary experiments suggest that waterjet technology can be an effective instrument for reshaping the cornea.

  6. REGION MERGING VIA GRAPH-CUTS

    Directory of Open Access Journals (Sweden)

    Jean Stawiaski

    2011-05-01

    Full Text Available In this paper, we discuss the use of graph-cuts to merge the regions of the watershed transform optimally. Watershed is a simple, intuitive and efficient way of segmenting an image. Unfortunately it presents a few limitations such as over-segmentation and poor detection of low boundaries. Our segmentation process merges regions of the watershed over-segmentation by minimizing a specific criterion using graph-cuts optimization. Two methods will be introduced in this paper. The first is based on regions histogram and dissimilarity measures between adjacent regions. The second method deals with efficient approximation of minimal surfaces and geodesics. Experimental results show that these techniques can efficiently be used for large images segmentation when a pre-computed low level segmentation is available. We will present these methods in the context of interactive medical image segmentation.

  7. Alternative Metal Hot Cutting Operations for Opacity

    Science.gov (United States)

    2014-11-01

    Principal Investigator NAVFAC Engineering and Expeditionary Warfare Center, EV11 Date Reviewed By: Name Internal Reviewer(optional) Date: Reviewed...is the oxy- fuel metal cutting, a hot combustion process that forms visible particulate matter (PM) emissions. Since the beginning of its program in...generation of the alternative fuel is created from virgin methanol instead of the original virgin ethylene glycol. The reason for this switch was because

  8. Promotion Signal: Proxy for a Price Cut?

    OpenAIRE

    Inman, J Jeffrey; McAlister, Leigh; Hoyer, Wayne D

    1990-01-01

    Evidence suggests that some consumers react to promotion signals without considering relative price information. We adopt Petty and Cacioppo's Elaboration Likelihood Model (ELM) to explain this behavior in terms of the ELM's peripheral route to pursuasion in which the promotion signal is taken as a cue for a price cut. Experimental results show that low need for cognition individuals react to the simple presence of a promotion signal whether or not the price of the promoted brand is reduced, ...

  9. 'Quick win' approach to cutting energy use.

    Science.gov (United States)

    O'Leary, John

    2010-05-01

    Among the many challenges the NHS currently faces is an urgent need to cut its burgeoning energy costs and, in specialist building management system manufacturer Trend Control Systems' words, its "massive carbon footprint". Part of the solution, the company argues, lies in making better use of existing building energy management systems (BEMS). Optimising their operation and performance can, key account manager John O'Leary explains, bring substantial savings without the need for additional investment.

  10. Concrete Cutting Refinement for Crater Repair

    Science.gov (United States)

    2015-08-01

    case scenarios for saw cutting due to their hardness. By definition, hardness is the abrasion resistance of aggregate, which is usually measured...loaders (CTL), or skid steers, are high- flow, rubber-tracked machines with quick disconnect fittings that are used for numerous tasks in the current...between the rates was 57 percent. This is not surprising as chert is much harder and more abrasion resistant than limestone. The Vermeer CC1531 with

  11. Laser welding, cutting and surface treatment

    International Nuclear Information System (INIS)

    Crafer, R.C.

    1984-01-01

    Fourteen articles cover a wide range of laser applications in welding, cutting and surface treatment. Future trends are covered as well as specific applications in shipbuilding, the manufacture of heart pacemakers, in the electronics industry, in automobile production and in the aeroengine industry. Safety with industrial lasers and the measurement of laser beam parameters are also included. One article on 'Lasers in the Nuclear Industry' is indexed separately. (U.K.)

  12. Quality assessment of forest cutting with chainsaw

    Directory of Open Access Journals (Sweden)

    Octávio Barbosa Plaster

    2012-06-01

    Full Text Available This research evaluated the quality of forest harvest using chainsaw, in farms in the south of Espirito Santo state, Brazil, considering aspects of quality and loss of wood left in the strains. A total of 250 m² plots were launched to collect data of forest cut with chainsaw, for evaluating the quality of the cut related mto: presence of skewers; crack damage; strains burst range nonstandard; strains without the notch directional, and the remaining height of the strain, in order to measure the loss of wood held in the strains. The main results were: the spike was present in 21.9% of the strains, the cracks in 17.2% of the strains, non-standard strains in 44.6% of them and unnotched directional strains in 34.5% of the evaluations. To check the influence of the realization of the directional notch on the height of the strains t-test, at 5% probability, has shown that there is an increased contribution to height of the strains, where the cut was made without the directional notch. The amount of wood held in the strains above the recommended maximum was, on average, 2.43 m³.ha-1, representing a loss of R$ 172.53 ha-1. It was verified that the loss of timber remaining in eucalyptus strains was higher in places where, for the logging, there was not done the directional notch. The items evaluated showed uneven quality, indicating the need to improve cutting with chainsaw.

  13. Evaluating optical hazards from plasma arc cutting.

    Science.gov (United States)

    Glassford, Eric; Burr, Gregory

    2018-01-01

    The Health Hazard Evaluation Program of the National Institute for Occupational Safety and Health evaluated a steel building materials manufacturer. The employer requested the evaluation because of concerns about optical radiation hazards from a plasma arc cutting system and the need to clarify eye protection requirements for plasma operators, other employees, and visitors. The strength of the ultraviolet radiation, visible radiation (light), and infrared radiation generated by the plasma arc cutter was measured at various distances from the source and at different operating amperages. Investigators also observed employees performing the plasma arc cutting. Optical radiation above safe levels for the unprotected eyes in the ultraviolet-C, ultraviolet-B, and visible light ranges were found during plasma arc cutting. In contrast, infrared and ultraviolet-A radiation levels during plasma arc cutting were similar to background levels. The highest non-ionizing radiation exposures occurred when no welding curtains were used. A plasma arc welding curtain in place did not eliminate optical radiation hazards to the plasma arc operator or to nearby employees. In most instances, the measured intensities for visible light, UV-C, and UV-B resulted in welding shade lens numbers that were lower than those stipulated in the OSHA Filter Lenses for Protection Against Radiant Energy table in 29 CFR 1910.133(a)(5). [1] Investigators recommended using a welding curtain that enclosed the plasma arc, posting optical radiation warning signs in the plasma arc cutter area, installing audible or visual warning cues when the plasma arc cutter was operating, and using welding shades that covered the plasma arc cutter operator's face to protect skin from ultraviolet radiation hazards.

  14. Shroud cutting techniques and collection systems for secondary radioactivity release

    International Nuclear Information System (INIS)

    Yokoi, H.; Watanabe, A.; Uetake, N.; Shimura, T.; Omote, T.; Adachi, H.; Murakami, S.; Kobayashi, H.; Gotoh, M.

    2001-01-01

    Replacement of in-core shroud has been conducted as part of the preventive maintenance program in Tsuruga-1. The EDM (electric discharged machining) and plasma cutting methods were applied to in-core shroud cutting and secondary cutting in the DSP (dryer/separator pool), respectively. The cutting systems were improved in order to decrease radioactive secondary products. 1) Fundamental EDM cutting tests: fundamental EDM cutting tests were carried out in order to study secondary products. It could be presumed that volatile Co-carbonyl compound was generated by using a carbon electrode. The Ag/W electrode was effective as EDM electrode for in-core shroud cutting to prevent generation of Co-carbonyl compound and to decrease the total amount of secondary products. 2) In-core shroud cutting in RPV (reactor pressure vessel): EDM cutting system with the Ag/W electrode and collection system could keep a good environment during in-core shroud cutting in Tsuruga-1. Activity concentration was lower value than limitation of mask charge level, 4E-6 Bq/cm 3 , even near the water surface. 3) Secondary plasma cutting in DSP: the secondary cutting work was successful in the point of reduction of working period and radiation exposure. The amount of radiation exposure was reduced to 60% of the planned value, because of adequate decontamination of the working environment and reduction of number of torch maintenance tasks by improvements of the underwater cutting device

  15. Multiplication of Patio roses by cutting

    Directory of Open Access Journals (Sweden)

    Denysko Iryna Leonidivna

    2013-12-01

    Full Text Available The experiment involved plants of 10 Patio rose cultivars of the National Dendrological Park "Sofiyivka" collection. The methods of propagation by cuttings worked out by Moscow Timiryazev Agricultural Academy were assumed as a basis. Callogenesis and regenerative capacity were estimated in accordance with Z.J. Ivanova scale (1982. The fact is ascertained that the success of rooting substantially depends on particularities of certain Patio rose cultivar. It is advisable to use cuttings from basal and medial parts of stems, with remaining leaves, taken within the last ten-day period of May – the first ten-day period of June. The pretreatment with rhizogenic medium "Kornevin" (reactant — indolebutyric acid is the most effective for rooting cuttings. The optimal for rooting is the two-layered substrate: the lower layer is a multicomponent soil compound of peat, perlite, sod soil and humus in ratio 1:1:1:1; the upper layer consists of sand. Seedlings of Patio roses cultivated in open ground during vegetation period form stems 1.8 times more vigorously than ones grown on the same place where they were rooted. The optimal period to transfer into bed is May. It is reasonable to use top removal in order to form vigorous stem system.

  16. Sinuous Flow in Cutting of Metals

    Science.gov (United States)

    Yeung, Ho; Viswanathan, Koushik; Udupa, Anirudh; Mahato, Anirban; Chandrasekar, Srinivasan

    2017-11-01

    Using in situ high-speed imaging, we unveil details of a highly unsteady plastic flow mode in the cutting of annealed and highly strain-hardening metals. This mesoscopic flow mode, termed sinuous flow, is characterized by repeated material folding, large rotation, and energy dissipation. Sinuous flow effects a very large shape transformation, with local strains of ten or more, and results in a characteristic mushroomlike surface morphology that is quite distinct from the well-known morphologies of metal-cutting chips. Importantly, the attributes of this unsteady flow are also fundamentally different from other well-established unsteady plastic flows in large-strain deformation, like adiabatic shear bands. The nucleation and development of sinuous flow, its dependence on material properties, and its manifestation across material systems are demonstrated. Plastic buckling and grain-scale heterogeneity are found to play key roles in triggering this flow at surfaces. Implications for modeling and understanding flow stability in large-strain plastic deformation, surface quality, and preparation of near-strain-free surfaces by cutting are discussed. The results point to the inadequacy of the widely used shear-zone models, even for ductile metals.

  17. Multidimensional Brain MRI segmentation using graph cuts

    International Nuclear Information System (INIS)

    Lecoeur, Jeremy

    2010-01-01

    This thesis deals with the segmentation of multimodal brain MRIs by graph cuts method. First, we propose a method that utilizes three MRI modalities by merging them. The border information given by the spectral gradient is then challenged by a region information, given by the seeds selected by the user, using a graph cut algorithm. Then, we propose three enhancements of this method. The first consists in finding an optimal spectral space because the spectral gradient is based on natural images and then inadequate for multimodal medical images. This results in a learning based segmentation method. We then explore the automation of the graph cut method. Here, the various pieces of information usually given by the user are inferred from a robust expectation-maximization algorithm. We show the performance of these two enhanced versions on multiple sclerosis lesions. Finally, we integrate atlases for the automatic segmentation of deep brain structures. These three new techniques show the adaptability of our method to various problems. Our different segmentation methods are better than most of nowadays techniques, speaking of computation time or segmentation accuracy. (authors)

  18. High pressure waterjet cutting industrial needs survey

    Science.gov (United States)

    Klavuhn, John; Baker, Bruce

    1989-08-01

    The results are presented of a survey conducted by personnel of the National Center for Excellence in Metalworking Technology (NCEMT) to assess the industrial needs in high pressure water jet cutting (WJC) technology. Survey forms were mailed to approximately 1400 individuals obtained from three mailing lists. The respondents included approximately 200 individuals associated with a variety of industries: 12 percent were WJC equipment suppliers, 40 percent were WJC users, and 48 percent were neither suppliers nor users. The survey addressed five specific areas of WJC technology: research and development, standards, systems, new products, and training and service. Results show that the need having the highest priority is the establishment of a database on WJC that contains the cutting parameters for a wide range of materials. Associated with this objective is the expressed need for an independent demonstration and test center for testing, data generation and operator training. A further need was found for establishing organized efforts in hardware development and research in mechanisms of cutting.

  19. Family planning funding cuts and teen childbearing.

    Science.gov (United States)

    Packham, Analisa

    2017-09-01

    Publicly funded family planning clinics provide low-cost and free contraception to nearly 1.5 million teens each year. In recent years, several states have considered legislation to defund family planning services, although little is known about how these cuts affect teen pregnancy. This paper fills this knowledge gap by exploiting a policy change in Texas that reduced funding for family planning services by 67% and resulted in over 80 clinic closures. I estimate the effects of the funding cuts on teen health outcomes using a difference-in-differences approach that compares the changes in teen birth rates in Texas counties that lost family planning funding to changes in counties outside of Texas with publicly funded clinics. I find that reducing funding for family planning services in Texas increased teen birth rates by approximately 3.4% over four years with effects concentrated 2-3 years after the initial cuts. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Heat-Affected Zone Studies Of Thermally Cut Structural Steels

    Science.gov (United States)

    1994-12-01

    KEYWORDS: : RESEARCH AND DEVELOPMENT : THERMAL CUTTING IS A PROCEDURE THAT IS INTEGRAL TO THE MANUFACTURE AND FABRICATION OF STEEL. THERMAL CUTTING IS PARTICULARLY IMPORTANT IN THE PRODUCTION OF PLATE STEELS, WHERE IT IS COMMONLY USED FOR TRIMMING TH...

  1. Cutting force simulation in milling with multi-edges cutter

    Science.gov (United States)

    Tamura, Shoichi; Matsumura, Takashi

    2017-10-01

    In the aircraft parts, the portion of titanium alloy, one of the light-weight and high mechanical strength materials, has been increased in terms of the fuel efficiency. Therefore, the effective technologies in cutting of titanium alloy should be established to promote the material removal rate with high production quality. Multi-edges milling cutters, on which many inserts are helically aligned, have been commercially available for millings of deep sinking in large axial depth of cuts. The paper presents an analytical prediction model to control the cutting force with alignment and geometry of the insert. In the model, three dimensional chip flow on each insert is interpreted as a piling up of the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities, where the chip flow direction is determined to minimize the cutting energy. Then, the cutting force is predicted in the determined chip flow model. The cutting tests were conducted to validate the force model.

  2. Local graph cut criterion for supervised dimensionality reduction

    Science.gov (United States)

    Zhang, Xiangrong; Zhou, Sisi; Jiao, Licheng

    2009-10-01

    Graph cut criterion has been proven to be robust and applicable in clustering problems. In this paper the graph cut criterion is applied to construct a supervised dimensionality reduction. A new graph cut, scaling cut, is proposed based on the classical normalized cut. Scaling cut depicts the relationship between samples, which makes it can handle the heteroscedastic and multimodel data in which LDA fails. Meanwhile, the solution to scaling cut is global optimal for it is a generalized eigenvalue problem. To obtain a more reasonable projection matrix and reduce the computational complexity as well, the localized k-nearest neighbor graph is introduced in, which leads to equivalent or better results compared with scaling cut.

  3. Non-Poissonian photon statistics from macroscopic photon cutting materials.

    Science.gov (United States)

    de Jong, Mathijs; Meijerink, Andries; Rabouw, Freddy T

    2017-05-24

    In optical materials energy is usually extracted only from the lowest excited state, resulting in fundamental energy-efficiency limits such as the Shockley-Queisser limit for single-junction solar cells. Photon-cutting materials provide a way around such limits by absorbing high-energy photons and 'cutting' them into multiple low-energy excitations that can subsequently be extracted. The occurrence of photon cutting or quantum cutting has been demonstrated in a variety of materials, including semiconductor quantum dots, lanthanides and organic dyes. Here we show that photon cutting results in bunched photon emission on the timescale of the excited-state lifetime, even when observing a macroscopic number of optical centres. Our theoretical derivation matches well with experimental data on NaLaF 4 :Pr 3+ , a material that can cut deep-ultraviolet photons into two visible photons. This signature of photon cutting can be used to identify and characterize new photon-cutting materials unambiguously.

  4. Finite pure integer programming algorithms employing only hyperspherically deduced cuts

    Science.gov (United States)

    Young, R. D.

    1971-01-01

    Three algorithms are developed that may be based exclusively on hyperspherically deduced cuts. The algorithms only apply, therefore, to problems structured so that these cuts are valid. The algorithms are shown to be finite.

  5. Influence of cutting parameters on the depth of subsurface deformed layer in nano-cutting process of single crystal copper.

    Science.gov (United States)

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Su, Hao; Wang, Zhiguo; Xie, Wenkun

    2015-12-01

    Large-scale molecular dynamics simulation is performed to study the nano-cutting process of single crystal copper realized by single-point diamond cutting tool in this paper. The centro-symmetry parameter is adopted to characterize the subsurface deformed layers and the distribution and evolution of the subsurface defect structures. Three-dimensional visualization and measurement technology are used to measure the depth of the subsurface deformed layers. The influence of cutting speed, cutting depth, cutting direction, and crystallographic orientation on the depth of subsurface deformed layers is systematically investigated. The results show that a lot of defect structures are formed in the subsurface of workpiece during nano-cutting process, for instance, stair-rod dislocations, stacking fault tetrahedron, atomic clusters, vacancy defects, point defects. In the process of nano-cutting, the depth of subsurface deformed layers increases with the cutting distance at the beginning, then decreases at stable cutting process, and basically remains unchanged when the cutting distance reaches up to 24 nm. The depth of subsurface deformed layers decreases with the increase in cutting speed between 50 and 300 m/s. The depth of subsurface deformed layer increases with cutting depth, proportionally, and basically remains unchanged when the cutting depth reaches over 6 nm.

  6. Performances of cutting fluids in turning. Formulated oil - E

    DEFF Research Database (Denmark)

    Axinte, Dragos A.; Steffanato, Simone

    Tool life is a parameter closely connected to the lubricating effect of a cutting fluid. Long tool life in turning corresponds to good lubrication and a process with good lubrication is preferred, since it normally results in lower tool wear and better surface quality. Cutting forces are mainly...... important for understanding the mechanism of the cutting process itself and to perform in this way data about the influence of the cutting fluids....

  7. CO2 Laser Cutting of Hot Stamping Boron Steel Sheets

    OpenAIRE

    Pasquale Russo Spena

    2017-01-01

    This study investigates the quality of CO2 laser cutting of hot stamping boron steel sheets that are employed in the fabrication of automotive body-in-white. For this purpose, experimental laser cutting tests were conducted on 1.2 mm sheets at varying levels of laser power, cutting speed, and oxygen pressure. The resulting quality of cut edges was evaluated in terms of perpendicularity tolerance, surface irregularity, kerf width, heat affected zone, and dross extension. Experimental tests wer...

  8. Cutting Forces Prediction in the Dry Slotting of Aluminium Stacks

    OpenAIRE

    SALGUERO, Jorge; CALAMAZ, Madalina; BATISTA, Moises; GIROT, Franck; MARCOS, Mariano

    2014-01-01

    International audience; Cutting forces are one of the inherent phenomena and a very significant indicator of themetal cutting process. The work presented in this paper is an investigation of the prediction of these parameters in slotting processes of UNS A92024-T3 (Al-Cu) stacks. So, cutting speed (V) and feed per tooth (fz) based parametric models, for experimental components of cutting force, F(fz,V) have been proposed. These models have been developed from the individual models extracted f...

  9. Performance of clonal olive tree gardens in successive cuts aiming cutting propagation

    Directory of Open Access Journals (Sweden)

    João Vieira Neto

    2011-03-01

    Full Text Available This work evaluated the performance of clonal olive tree gardens in successive cuts aiming cutting propagation. The clonal garden was installed in March 2006, in grooves 40 cm deep. Two cultivars (Ascolano 315 and Arbequina were evaluated and cut in 2007, 2008 and 2009. The test was carried out in split plot in time in a randomized block design with five replications. The plots were composed of three lines, one meter spaced between them, three plants in each line, spaced 0,5 m from each other, totaling nine plants per plot, being evaluated only the three most vigorous plants. For evaluation, three plants were pruned 20 cm height above soil, after 12 months of cultivation, it was evaluated the yield of cuttings with four knots and two pairs of leaves; plants height (m, torso diameter the 20 cm height of the soil (cm; branches length (m; and total green mass accumulated (kg. In most features evaluated, the best results were observed in the ‘Ascolano 315’. The successive cuts may be extended over a three year period. The parameter estimates indicate that plants of both cultivars y responded satisfactorily to regrowth.

  10. Study on optimal surface property of WC-Co cutting tool for aluminium alloy cutting

    International Nuclear Information System (INIS)

    Nizar, Mohd; Arimatsu, Naoya; Kawamitsu, Hiroshi; Takai, Kazuteru; Fukumoto, Masahiro

    2016-01-01

    The light weight property as well as high corrosion resistance of aluminium alloy has increased their demand especially in automobile industries. Aluminium alloy as a matter of fact has a low melting point and high ductility that severely adhere to the cutting tool surface and cause deterioration of chip evacuation. This problem often resulting in tools breakage. In this paper, in order to impart functions of anti-adhesion, we propose a technique by controlling the grinding marks micro texture on the tool surface by using the blast polishing treatment without any coating technologies. The results show that the tool which underwent polishing treatment reduces the cutting force as well as the aluminium adherence during the initial cutting process, and become worst as the process cutting continues. These results indicate that grinding mark texture improves the anti-adhesion by reducing the contact area during cutting and provide storage for the lubricant. In addition, too much polishing on the tool surface may remove these textures and resultantly worsen the tool performance. (paper)

  11. Materials Comparison of Cutting Tools Functional Parts for Cutting of Electrical Engineering Sheets

    Directory of Open Access Journals (Sweden)

    Jan ZLÁMALÍK

    2012-06-01

    Full Text Available Paper concerns the comparison of functional materials parts of cutting tools used for the production of stator and rotor sheets in the electrical industry from point of view of their life. Alternatives and the properties of metal used for the production of stator and rotor components in electrical rotating machines are analysed. The main factors affecting the life of cutting tools of functional parts are analysed, one of the most important is the cutting tool functional parts material itself. Comparison of three variants of the cuttong tool funkcional parts material – 19 436 tool steel (chrome steel according to the Czech State Standard 41 9436, 19 830 high speed steel according to the Czech State Standard 41 9830 and a special powder metallurgy product – ledeburite tool steel Vanadis 10. Useful lifes of the functional components of individual cutting tools performances can be calculated from the theoretical lifes by their multiplying the coefficients of the tool design and the cutting edges shape complexity.

  12. Study on optimal surface property of WC-Co cutting tool for aluminium alloy cutting

    Science.gov (United States)

    Nizar, Mohd; Arimatsu, Naoya; Kawamitsu, Hiroshi; Takai, Kazuteru; Fukumoto, Masahiro

    2016-02-01

    The light weight property as well as high corrosion resistance of aluminium alloy has increased their demand especially in automobile industries. Aluminium alloy as a matter of fact has a low melting point and high ductility that severely adhere to the cutting tool surface and cause deterioration of chip evacuation. This problem often resulting in tools breakage. In this paper, in order to impart functions of anti-adhesion, we propose a technique by controlling the grinding marks micro texture on the tool surface by using the blast polishing treatment without any coating technologies. The results show that the tool which underwent polishing treatment reduces the cutting force as well as the aluminium adherence during the initial cutting process, and become worst as the process cutting continues. These results indicate that grinding mark texture improves the anti-adhesion by reducing the contact area during cutting and provide storage for the lubricant. In addition, too much polishing on the tool surface may remove these textures and resultantly worsen the tool performance.

  13. Short Communication Effect of species, cutting position and ...

    African Journals Online (AJOL)

    Effect of the cutting position, terminal and subterminal, and rooting substance on the rooting of cuttings of two Cyclopia species (Cyclopia genistoides and C. intermedia) taken in winter, spring or summer was studied under controlled glasshouse conditions. Cuttings taken in summer, irrespective of the species, rooted better ...

  14. Inner tubes cutting method by electrical arc saw

    International Nuclear Information System (INIS)

    Thome, P.

    1990-01-01

    The research program deals on the definition of tools used for dismantling steam generator tubes bundle of PWR and on tool used for cutting pipes of great diameter by using the process of cutting by electrical arc saw. The remote tools are used for cutting by the interior pipes of contamined circuits [fr

  15. 7 CFR 318.13-23 - Cut flowers from Hawaii.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Cut flowers from Hawaii. 318.13-23 Section 318.13-23... SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated Articles From Hawaii and the Territories § 318.13-23 Cut flowers from Hawaii. (a) Except for cut blooms and leis...

  16. An Experimental Study of the Cutting Forces in Metal Turning

    Directory of Open Access Journals (Sweden)

    Zoltan Iosif Korka

    2013-09-01

    Full Text Available Cutting forces are classified among the most important technological parameters in machining process. Cutting forces are the background for the evaluation of the necessary machining power, as well as for dimensioning of the tools. Cutting forces are also having a major influence on the deformation of the work piece machined, its dimensional accuracy, and machining system stability.

  17. Correlation of cutting fluid performance in different machining operations

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Belluco, Walter

    2001-01-01

    An analysis of cutting fluid performance in different metal cutting operations is presented, based on experimental investigations in which type of operation, performance criteria, work material, and fluid type are considered. Cutting fluid performance was evaluated in turning, drilling, reaming a...

  18. Functional anatomy of the water transport system in cut chrysanthemum

    NARCIS (Netherlands)

    Nijsse, J.

    2001-01-01

    Cut flowers show a wide variance of keepability. The market demands more and more a guaranteed quality. Therefore, methods must be developed to predict vase life of cut flowers. Chrysanthemum ( Dendranthema x grandiflorum Tzvelev) and some other cut flowers suffer from

  19. Validation of the standardized and simplified cutting bill

    Science.gov (United States)

    Urs Buehlmann; D. Earl Kline; Janice K. Wiedenbeck; R., Jr. Noble

    2008-01-01

    This research validated the framework for the standardized and simplified cutting bill presented in an earlier paper. The cutting bill validation was carried out in two ways. First, all 20 of the cutting bill's part groups were examined to determine if significant yield influences resulted from changing specific part sizes within the boundaries of a given part...

  20. 49 CFR 213.122 - Torch cut rail.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Torch cut rail. 213.122 Section 213.122..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.122 Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used in Classes 3 through 5...

  1. Cavity cutting efficiency of a Bioglass TM and alumina powder ...

    Indian Academy of Sciences (India)

    Thirty human enamel blocks and microscope glass slides of 0.5mm thickness were randomly divided into these three groups. The time taken to cut a hole through the glass slide and for the cutting of human enamel blocks was recorded, the cutting time was fixed at 15 s. The depths of the cavities were measured using a ...

  2. Laser cutting, State of the art and technological trends

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    1999-01-01

    In this paper a short review of the development trends in laser cutting will be given. The technoloty which is the fastest expanding industrial production technology will develop in both its core market segment: Flat bed cutting of sheet metal as it will expand in heavy industry and in cutting of 3...

  3. 21 CFR 872.4120 - Bone cutting instrument and accessories.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4120 Bone cutting instrument and accessories. (a) Identification. A bone cutting instrument and accessories is a metal device intended for use... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone cutting instrument and accessories. 872.4120...

  4. Hollow needle used to cut metal honeycomb structures

    Science.gov (United States)

    Gregg, E. A.

    1966-01-01

    Hollow needle tool cuts metal honeycomb structures without damaging adjacent material. The hollow needle combines an electrostatic discharge and a stream of oxygen at a common point to effect rapid, accurate metal cutting. The tool design can be varied to use the hollow needle principle for cutting a variety of shapes.

  5. 21 CFR 886.4150 - Vitreous aspiration and cutting instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vitreous aspiration and cutting instrument. 886.4150 Section 886.4150 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... cutting instrument. (a) Identification. A vitreous aspiration and cutting instrument is an electrically...

  6. 21 CFR 882.4190 - Clip forming/cutting instrument.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Clip forming/cutting instrument. 882.4190 Section 882.4190 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES.../cutting instrument. (a) Identification. A clip forming/cutting instrument is a device used by the...

  7. 7 CFR 58.726 - Cutting and grinding.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections of...

  8. Stabilization/solidification of synthetic Nigerian drill cuttings | Opete ...

    African Journals Online (AJOL)

    Stabilization/solidification of synthetic Nigerian drill cuttings. SEO Opete, IA Mangibo, ET Iyagba. Abstract. In the Nigerian oil and gas industry, large quantities of oily and synthetic drill cuttings are produced annually. These drill cuttings are heterogeneous wastes which comprises of hydrocarbons, heavy metals and ...

  9. 29 CFR 1926.351 - Arc welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Arc welding and cutting. 1926.351 Section 1926.351 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Welding and Cutting § 1926.351 Arc welding and... for arc welding and cutting, and are of a capacity capable of safely handling the maximum rated...

  10. 29 CFR 1915.56 - Arc welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Arc welding and cutting. 1915.56 Section 1915.56 Labor... § 1915.56 Arc welding and cutting. The provisions of this section shall apply to ship repairing... specifically designed for arc welding and cutting and are of a capacity capable of safely handling the maximum...

  11. Successful natural regeneration cuttings in California true firs.

    Science.gov (United States)

    Donald T. Gordon

    1979-01-01

    In stands of mixed white and red fir in northeastern California, cuttings for natural regeneration became well stocked with seedlings within 2 to 5 years after cutting. Seed tree and shelterwood cuttings, clearcut strips not more than 3 chains (60 m) wide, and patches not exceeding 4 chains (80 m) width were studied. Incidence of damage among residual trees in or...

  12. Development of underwater laser cutting technique for steel and ...

    Indian Academy of Sciences (India)

    Laser cutting; underwater laser cutting; fibre optic beam delivery; Nd:YAG laser; material processing; heat affected zone; microstructure. PACS Nos 42.62.Cf; 42.62.-b; 42.55.Rz; 42.81.Ai; 42.81.-i. 1. Introduction. Underwater laser cutting and welding has many applications in nuclear facilities and shiping industry and is a ...

  13. Investigation of cutting-induced damage in CMC bend bars

    Directory of Open Access Journals (Sweden)

    Neubrand A.

    2015-01-01

    Full Text Available Ceramic matrix composites (“CMC” with a strong fibre-matrix interface can be made damage-tolerant by introducing a highly porous matrix. Such composites typically have only a low interlaminar shear strength, which can potentially promote damage when preparing specimens or components by cutting. In order to investigate the damage induced by different cutting methods, waterjet cutting with and without abrasives, laser-cutting, wire eroding and cutoff grinding were used to cut plates of two different CMCs with a matrix porosity up to 35 vol.-%. For each combination of cutting method and composite, the flexural and interlaminar shear strength of the resulting specimens was determined. Additionally, the integrity of the regions near the cut surfaces was investigated by high-resolution x-ray computer tomography. It could be shown that the geometrical quality of the cut is strongly affected by the cutting method employed. Laser cut and waterjet cut specimens showed damage and delaminations near the cut surface leading to a reduced interlaminar shear strength of short bend bars in extreme cases.

  14. Cold storage of rooted and non-rooted carnation cuttings

    African Journals Online (AJOL)

    USER

    2010-06-14

    Jun 14, 2010 ... The specific objectives of this study were to evaluate the effect of storage duration on the survival rate of rooted cuttings and to determine the rooting and survival rates of non-rooted cuttings for two standard carnation cultivars (that is., Dianora and Vittorio). The survival rates of rooted cuttings showed ...

  15. Minimizing waste (off-cuts using cutting stock model: The case of one dimensional cutting stock problem in wood working industry

    Directory of Open Access Journals (Sweden)

    Gbemileke A. Ogunranti

    2016-09-01

    Full Text Available Purpose: The main objective of this study is to develop a model for solving the one dimensional cutting stock problem in the wood working industry, and develop a program for its implementation. Design/methodology/approach: This study adopts the pattern oriented approach in the formulation of the cutting stock model. A pattern generation algorithm was developed and coded using Visual basic.NET language. The cutting stock model developed is a Linear Programming (LP Model constrained by numerous feasible patterns. A LP solver was integrated with the pattern generation algorithm program to develop a one - dimensional cutting stock model application named GB Cutting Stock Program. Findings and Originality/value: Applying the model to a real life optimization problem significantly reduces material waste (off-cuts and minimizes the total stock used. The result yielded about 30.7% cost savings for company-I when the total stock materials used is compared with the former cutting plan. Also, to evaluate the efficiency of the application, Case I problem was solved using two top commercial 1D-cutting stock software.  The results show that the GB program performs better when related results were compared. Research limitations/implications: This study round up the linear programming solution for the number of pattern to cut. Practical implications: From Managerial perspective, implementing optimized cutting plans increases productivity by eliminating calculating errors and drastically reducing operator mistakes. Also, financial benefits that can annually amount to millions in cost savings can be achieved through significant material waste reduction. Originality/value: This paper developed a linear programming one dimensional cutting stock model based on a pattern generation algorithm to minimize waste in the wood working industry. To implement the model, the algorithm was coded using VisualBasic.net and linear programming solver called lpsolvedll (dynamic

  16. Immune defense in leaf-cutting ants

    DEFF Research Database (Denmark)

    Armitage, Sophie A O; Broch, Jens F; Marín, Hermogenes Fernández

    2011-01-01

    -fostering experiment designed to address the influences of genotype and social rearing environment upon individual and social immune defenses. We used a multiply mating leaf-cutting ant, enabling us to test for patriline effects within a colony, as well as cross-colony matriline effects. The worker's father influenced...... social defense, a Pseudonocardia bacteria that helps to control pathogens in the ants' fungus garden, showed a significant colony of origin by rearing environment interaction, whereby ants that acquired the bacteria of a foster colony obtained a less abundant cover of bacteria: one explanation...

  17. High pressure water jet cutting and stripping

    Science.gov (United States)

    Hoppe, David T.; Babai, Majid K.

    1991-01-01

    High pressure water cutting techniques have a wide range of applications to the American space effort. Hydroblasting techniques are commonly used during the refurbishment of the reusable solid rocket motors. The process can be controlled to strip a thermal protective ablator without incurring any damage to the painted surface underneath by using a variation of possible parameters. Hydroblasting is a technique which is easily automated. Automation removes personnel from the hostile environment of the high pressure water. Computer controlled robots can perform the same task in a fraction of the time that would be required by manual operation.

  18. High Performance Grinding and Advanced Cutting Tools

    CERN Document Server

    Jackson, Mark J

    2013-01-01

    High Performance Grinding and Advanced Cutting Tools discusses the fundamentals and advances in high performance grinding processes, and provides a complete overview of newly-developing areas in the field. Topics covered are grinding tool formulation and structure, grinding wheel design and conditioning and applications using high performance grinding wheels. Also included are heat treatment strategies for grinding tools, using grinding tools for high speed applications, laser-based and diamond dressing techniques, high-efficiency deep grinding, VIPER grinding, and new grinding wheels.

  19. Sensitiveness of jasmine cuttings to gamma radiation

    International Nuclear Information System (INIS)

    Devaiah, K.A.; Srivastava, H.C.

    1989-01-01

    Half lethal dose (LD 50 ) gamma radiation for five genotypes of jasmine and the effect of such radiation on their rooting parameters were studied. The LD 50 was close to 2.5 krad for Jasminum grandiflorum var. Pink Pin, 0.5 krad for var. Pink Thrum, 2.5 krad for J. flexile Valh., 1 krad for J. calophyllum Wall and 2 krad for J. sambac Ait var. 'Gundumalli'. Percentage of rooting, number of roots per cutting, length and thickness of roots decreased with increase in intensity of gamma irradiation. (author) 8 refs.; 4 tabs

  20. Evaluation of Cutting Fluids in Multiple Reaming of Stainless Steel

    DEFF Research Database (Denmark)

    Belluco, Walter; Zeng, Z.; De Chiffre, Leonardo

    2001-01-01

    An investigation on the effect of different cutting fluids in reaming is presented. The performance of three water based cutting fluids and one cutting oil was compared to that of a reference water based commercial product by measurement of cutting forces, surface roughness and part accuracy. Three...... subsequent reaming operations were carried out on austenitic stainless steel using high-speed-steel and solid carbide tools. The tested fluids were all significantly different from the reference fluid in at least some of the tested conditions. Significant differences down to 2 percent in cutting forces and 6...