Sample records for black powder substitutes

  1. Coal as a Substitute for Carbon Black

    NASA Technical Reports Server (NTRS)

    Kushida, R. O.

    1982-01-01

    New proposal shows sprayed coal powder formed by extrusion of coal heated to plastic state may be inexpensive substitute for carbon black. Carbon black is used extensively in rubber industry as reinforcing agent in such articles as tires and hoses. It is made from natural gas and petroleum, both of which are in short supply.

  2. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Resources 1 2010-07-01 2010-07-01 false Black powder. 56.6901 Section 56.6901 Mineral... Explosives General Requirements § 56.6901 Black powder. (a) Black powder shall be used for blasting only when a...

  3. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  4. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  5. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  6. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  7. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  8. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  9. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  10. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...6901 Black powder. (a) Black powder shall be used for...stone. (b) Containers of black powder shall be— (1) Nonsparking...of this section. (c) Black powder shall be transferred...damaged explosives. (f) Holes shall not be reloaded for...

  11. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Resources 1 2010-07-01 2010-07-01 false Black powder. 57.6901 Section 57.6901 Mineral...Requirements-Surface and Underground § 57.6901 Black powder. (a) Black powder shall be used for blasting only when a...

  12. Preparation of substituted barium ferrite powders

    Microsoft Academic Search

    A. Grusková; J. Sláma; M. Michalíková; J. Lipka; I. Tóth; P. Kabos

    1991-01-01

    Pure and (Co, Ti)-substituted Ba ferrites, produced by the citration process with the initial Fe to Ba ratio equal to 11.2, have been studied. The substitution x in Ba(Co, Ti)xFe12-xO19 has been varied from 0 to 1.1. The mechanism of the magnetic structure formation has been controlled by Mössbauer and infrared spectroscopy combined with magnetic susceptibility measurements. The substitution x

  13. 49 CFR 173.170 - Black powder for small arms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2 2010-10-01 2010-10-01 false Black powder for small arms. 173.170 Section 173...Materials Other Than Class 1 and Class 7 § 173.170 Black powder for small arms. Black powder for small arms that has been...

  14. Black powder handgun deaths remain an uncommon event.

    PubMed

    Hartwig, Sven; Tsokos, Michael; Byard, Roger W

    2009-12-01

    Although it was predicted that there would be an increase in the use of black powder guns due to their greater ease of procurement with less government control on sales, this does not seem to have been the general experience. To determine the rate of use of black powder handguns in shooting deaths in Berlin, Germany, review of the files of the Institute of Legal Medicine and Forensic Sciences, Charité-Universitätsmedizin Berlin was conducted over a 10-year period from 1997 to 2006. Out of total 85 gunshot deaths, there were only 3 where black powder handguns were used (3.5%). The cases involved 3 males aged 55, 62, and 63 years, respectively, all of whom had committed suicide with black powder percussion handguns, using 0.45, 0.56, and 0.36 caliber weapons. The source of the guns could not be determined. Wounds were characterized by excessive soot and propellant soiling and tattooing. The low number of fatalities involving black powder guns in a large forensic institution in Berlin, Germany, suggests that limiting access to such weapons would have little effect on total numbers of gunshot deaths. Simple loading mechanisms and reliability appear to be more important features influencing the choice of a handgun, rather than mere availability. PMID:19901807

  15. 40 CFR 721.10150 - Carbon black, (4-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Carbon black, (4-methylphenyl)-modified, substituted...Chemical Substances § 721.10150 Carbon black, (4-methylphenyl)-modified, substituted...substance identified generically as carbon black,...

  16. 40 CFR 721.10149 - Carbon black, (3-methylphenyl)-modified, substituted (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Carbon black, (3-methylphenyl)-modified, substituted...Chemical Substances § 721.10149 Carbon black, (3-methylphenyl)-modified, substituted...substance identified generically as carbon black,...

  17. Sintering Behavior of Magnesium-Substituted Fluorapatite Powders Prepared by Hydrothermal Method

    PubMed Central

    Nasr, S.; Bouzouita, K.

    2011-01-01

    Magnesium-substituted fluorapatite powders were synthesized by hydrothermal method, and their sintering behavior was investigated by dilatometry in the temperature range 25–1100°C. Analysis of the obtained powders by X-ray diffraction and 31P NMR spectroscopy showed that the powders consisted of a single apatite phase and no amorphous phase has been formed. Compared to pure fluorapatite, the shrinkage of the substituted samples occurred in two steps and the temperature at which the sintering rate was maximum is lower. In addition, the shrinkage was interrupted by an expansion of the samples due to the formation of a liquid phase. The latter phase led to the crystallization of needle-crystals by a dissolution-diffusion-reprecipitation process. PMID:21577315

  18. Polyolefin backbone substitution in binders for low temperature powder injection moulding feedstocks.

    PubMed

    Hausnerova, Berenika; Kuritka, Ivo; Bleyan, Davit

    2014-01-01

    This paper reports the substitution of polyolefin backbone binder components with low melting temperature carnauba wax for powder injection moulding applications. The effect of various binder compositions of Al?O? feedstock on thermal degradation parameters is investigated by thermogravimetric analysis. Within the experimental framework 29 original feedstock compositions were prepared and the superiority of carnauba wax over the polyethylene binder backbone was demonstrated in compositions containing polyethylene glycol as the initial opening agent and governing the proper mechanism of the degradation process. Moreover, the replacement of synthetic polymer by the natural wax contributes to an increase of environmental sustainability of modern industrial technologies. PMID:24583880

  19. Influence of Mg-substitution on the physicochemical properties of calcium phosphate powders

    SciTech Connect

    Marchi, J. [University of Erlangen-Nuernberg, Department of Materials Science-Biomaterials, Henkestr. 91, D-91052 Erlangen (Germany); Institute of Energetic and Nuclear Research (IPEN), Centre of Science and Materials Technology, Department of Ceramics, Av. Prof. Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil); Dantas, A.C.S. [University of Erlangen-Nuernberg, Department of Materials Science-Biomaterials, Henkestr. 91, D-91052 Erlangen (Germany); Greil, P. [University of Erlangen-Nuernberg, Department of Materials Science-Biomaterials, Henkestr. 91, D-91052 Erlangen (Germany); Bressiani, J.C. [Institute of Energetic and Nuclear Research (IPEN), Centre of Science and Materials Technology, Department of Ceramics, Av. Prof. Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil); Bressiani, A.H.A. [Institute of Energetic and Nuclear Research (IPEN), Centre of Science and Materials Technology, Department of Ceramics, Av. Prof. Lineu Prestes, 2242, 05508-000 Sao Paulo, SP (Brazil); Mueller, F.A. [University of Erlangen-Nuernberg, Department of Materials Science-Biomaterials, Henkestr. 91, D-91052 Erlangen (Germany)]. E-mail: Frank.Mueller@ww.uni-erlangen.de

    2007-06-05

    Tricalcium phosphate based ceramics (TCP) are bioresorbable and thereby considered to be promising bone replacement materials. The differences in crystal structure between {alpha} and {beta}-TCP phases gives rise for different dissolution rates in vitro and in vivo, which may alter the bioresorbable behavior of TCP ceramics. It is suggested that the addition of magnesium ions, which are also present in biological tissues, stabilizes {beta}-phase to higher temperatures and thus enables the sintering of {beta}-TCP at elevated temperatures compared to Mg free TCP. In this paper, Mg-substituted TCP, with the general formula (Ca{sub 1-x}Mg {sub x}){sub 3}(PO{sub 4}){sub 2} and 0.01 {<=} x {<=} 0.045, were produced by wet chemical synthesis from Ca(OH){sub 2}, H{sub 3}PO{sub 4} and MgO, after calcinations at three different temperatures between 750 and 1050 deg. C. The influence of different amounts of Mg substitution on the physical properties, microstructure, and sintering behavior of calcium phosphate powders was evaluated. Thermal analytical techniques, together with X-ray diffraction analysis, were successfully combined in order to characterize the occurring phase transformations during annealing of the powders. The results show that the addition of small amounts of Mg (up to 1.5 mol%) are adequate to postpone the {beta}-{alpha} TCP phase transformation to 1330 deg. C and to accelerate the densification process during sintering of {beta}-TCP ceramics.

  20. Direct 3D powder printing of biphasic calcium phosphate scaffolds for substitution of complex bone defects.

    PubMed

    Castilho, Miguel; Moseke, Claus; Ewald, Andrea; Gbureck, Uwe; Groll, Jürgen; Pires, Inês; Teßmar, Jörg; Vorndran, Elke

    2014-03-01

    The 3D printing technique based on cement powders is an excellent method for the fabrication of individual and complex bone substitutes even in the case of large defects. The outstanding bone remodeling capacity of biphasic calcium phosphates (BCPs) containing hydroxyapatite (HA) as well as tricalcium phosphate (TCP) in varying ratios makes the adaption of powder systems resulting in BCP materials to this fabrication technique a desirable aim. This study presents the synthesis and characterization of a novel powder system for the 3D printing process, intended for the production of complexly shaped BCP scaffolds by a hydraulic setting reaction of calcium carbonate and TCP with phosphoric acid. The HA/TCP ratio in the specimens could be tailored by the calcium/phosphate ratio of the starting powder. The scaffolds could be fabricated with a dimensional accuracy of >96.5% and a minimal macro pore size of 300 µm. Independent of the phase composition the printed specimens showed a microporosity of approximately 68%, while the compressive strength strongly depended on the chemical composition and increased with rising TCP content in the scaffolds to a maximum of 1.81 MPa. Post-treatment of the scaffolds with a polylactic-co-glycolic acid-solution enhanced the mechanical properties by a factor of 8. In vitro studies showed that all BCP scaffolds were cytocompatible and enhanced the cell viability as well as the cell proliferation, as compared with pure TCP. Cell proliferation is even better on BCP when compared to HA and cell viability is in a similar range on these materials. PMID:24429776

  1. Structure, Stoichiometry, and Phase Purity of Calcium Substituted Lanthanum Manganite Powders

    NASA Astrophysics Data System (ADS)

    Faaland, S.; Knudsen, K. D.; Einarsrud, M.-A.; Rørmark, L.; Høier, R.; Grande, T.

    1998-11-01

    Calcium-doped lanthanum manganite La 1- xCa xMnO 3, synthesized by the glycine/nitrate method, was characterized by high resolution synchrotron X-ray powder diffraction, electron diffraction, and infrared spectroscopy. A strong correlation was observed between the cooling rate from the calcination temperature and the powder quality, indicating the importance of a homogeneous oxygen stoichiometry. The structure refinement reveals that La 1- xCa xMnO 3with x=0.2, 0.3, 0.4, and 0.6 has orthorhombic symmetry with space group Pnma. The MnO 6octahedra are fairly symmetrical, but the octahedra are tilted about 20° relative to the ideal perovskite structure. Infrared spectroscopy revealed that only the O-Mn-O bending mode is significantly influenced by the substitution of La with Ca. In La 0.8Ca 0.2MnO 3we found diffraction evidence of a superstructure in domains in some of the grains. We propose that the superstructure in La 0.8Ca 0.2MnO 3is due to ordering of Ca 2+ions on A(La 3+) sites in the perovskite ABO 3structure.

  2. Structure, stoichiometry, and phase purity of calcium substituted lanthanum manganite powders

    SciTech Connect

    Faaland, S.; Einarsrud, M.A.; Roermark, L.; Hoeier, R.; Grande, T. [Norwegian Univ. of Science and Technology, Trondheim (Norway)] [Norwegian Univ. of Science and Technology, Trondheim (Norway); Knudsen, K.D. [ESRF, Grenoble (France)] [ESRF, Grenoble (France)

    1998-11-01

    Calcium-doped lanthanum manganite La{sub 1{minus}x}Ca{sub x}MnO{sub 3}, synthesized by the glycine/nitrate method, was characterized by high resolution synchrotron X-ray powder diffraction, electron diffraction, and infrared spectroscopy. A strong correlation was observed between the cooling rate from the calcination temperature and the powder quality, indicating the importance of a homogeneous oxygen stoichiometry. The structure refinement reveals that La{sub 1{minus}x}Ca{sub x}MnO{sub 3} with x = 0.2, 0.3, 0.4, and 0.6 has orthorhombic symmetry with space group Pnma. The MnO{sub 6} octahedra are fairly symmetrical, but the octahedra are tilted about 20{degree} relative to the ideal perovskite structure. Infrared spectroscopy revealed that only the O-Mn-O bending mode is significantly influenced by the substitution of La with Ca. In La{sub 0.8}Ca{sub 0.2}MnO{sub 3} the authors found diffraction evidence of a superstructure in domains in some of the grains. They propose that the superstructure in La{sub 0.8}Ca{sub 0.2}MnO{sub 3} is due to ordering of Ca{sup 2+} ions on A (La{sup 3+}) sites in the perovskite ABO{sub 3} structure.

  3. Carbon Powders Prepared by Ultrasonic Spray Pyrolysis of Substituted Alkali Benzoates Sara E. Skrabalak and Kenneth S. Suslick*

    E-print Network

    Suslick, Kenneth S.

    Carbon Powders Prepared by Ultrasonic Spray Pyrolysis of Substituted Alkali Benzoates Sara E Ultrasonic spray pyrolysis (USP) has been used to prepare carbon spheres from aqueous solutions limiting their utility. Ultrasonic spray pyrolysis (USP) is well-suited for the continuous production

  4. Synthesis of SiC Powders by Carbothermal Reduction of Enriched Brown Sepiolite with Carbon Black

    NASA Astrophysics Data System (ADS)

    Ba?ci, Cengiz; Arik, Halil

    2013-04-01

    Ultrafine ?-silicon carbide (?-SiC) powders were successfully synthesized by carbothermal-reduction reaction (CRR) of sepiolite. Sepiolite of Turkish deposits as a silica (SiO2) precursor and carbon black as a reducing agent were mixed with constant C/SiO2 molar ratio of 4. Mixed powders were subjected to CRR at temperatures of 1450, 1500, and 1550 °C for 1 h in an atmosphere-controlled tube furnace under argon flow of 5 cm3/min. The precursor and resultant powder products were characterized by XRD, SEM, and EDX. Phase transformation was observed in powder products after CRR as a function of the reaction temperature. The results show that the cotton-like nature of sepiolite makes it an effective mineral precursor for synthesis of SiC powders, and that SiC transformation was optimized at 1550 °C with a particle size of approximately 200 nm.

  5. Organo-montmorillonite as substitute of carbon black in natural rubber compounds

    Microsoft Academic Search

    M Arroyo; M. A López-Manchado; B Herrero

    2003-01-01

    The use of octadecylamine modified montmorillonite as substitute of carbon black in natural rubber (NR) compounds is studied. Rubber with 10 parts per hundred resin (phr) of pristine (clay) and octadecylamine modified montmorillonite (organoclay) were compared with 10 and 40phr carbon black as filler. The modified silicate is analysed by X-ray, FTIR and thermogravimetric analysis. Vulcametric curves show that the

  6. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1985-01-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  7. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted...Chemical Substances § 721.10075 Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted...substance identified generically as carbon black, 4-[[2-(Sulfooxy)...

  8. Investigation of Ga substitution in ZnO powder and opto-electronic properties.

    PubMed

    Serier, Hélène; Demourgues, Alain; Gaudon, Manuel

    2010-08-01

    Two sets of Ga-doped ZnO powders were synthesized via solid-state and Pechini routes with a substitution rate varying from 0 to 4 mol %. The gallium solubility limit is strongly dependent on the synthesis history. Indeed, a low temperature annealing allows incorporating about 1.5 mol % (X-ray diffraction (XRD), inductive coupled plasma spectroscopy (ICP), optical properties) whereas under 0.1% of dopant is introduced after thermal treatment at high temperature: 1500 degrees C (from XRD and pellets conductivity). The incorporation of gallium leads to an anisotropic distortion of the zincite crystal lattice (a and c parameters increase and decrease, respectively, versus the Ga content leading to a decrease of the c/a ratio) which can be explained from the valence bond model. XRD analysis, chemical titration by ICP, and conductivity measurements (on pellets obtained at high temperature) allow determining accurately the maximum Ga content in the zincite. The optical properties (IR absorption efficiency) linked to electron carriers are directly correlated to the gallium rate introduced in ZnO oxide; nevertheless, the non linear correlation between these two parameters tends to show that the concentration of charge carriers in the system is not equal to the amount of Ga(3+) atoms inserted per ZnO volume unit. A saturation regime is observed and was here explained once again on the basis of the valence band model by the increase of inhibiting p type defects with the increase of (n-type donors) Ga(3+) concentration. PMID:20593782

  9. Organic geochemistry and petroleum potential of Pennsylvanian black shales, Powder River and Denver basins

    SciTech Connect

    Clayton, J.L.; Lubeck, C.M.; King, J.D.; Daws, T.A.

    1987-05-01

    Thin, Middle Pennsylvanian organic-rich black shales (cumulative thickness generally less than 7 m) underlie much of the northern Denver basin and the southeastern Powder River basin. In the Powder River basin, these shales are part of the middle member of the Minnelusa Formation. During Desmoinesian time, the present-day area of the southeastern Powder River basin and the Nebraska panhandle was a shallow, at times highly saline restricted sea. In contrast, the black shales were deposited in a marine environment with normal salinity in the present-day area of northeastern Colorado, which was probably continuous with the Mid-Continent Pennsylvanian sea. Total organic carbon content of all the black shales is high (up to 20 wt. %) except along the margins of the ancient seaway and along the boundary between the open sea and the restricted basin (TOC < 2 wt. %). Extractable organic matter in the black shales is predominantly of marine origin. Evidence for marine organic material includes a predominance of low-molecular-weight alkanes (< C20) and absence of long-chain alkanes (> C25), very low saturated/aromatic hydrocarbon ratios (avg. 0.5), and relatively low pristane/phytane ratios (0.7-1.3). Although the black shales were apparently deposited in uniformly low-oxygen marine conditions, the restricted basin and open marine environments can be differentiated by organic geochemical analysis. Chloroform extracts from black shales from the restricted basin environment contain abundant red pigments, most likely derived from bacteria or algae requiring high salinity for growth. In contrast, extracts from the open marine shales, although equally organic rich, are devoid of pigments, suggesting depositional under conditions of normal seawater salinity. In bulk, organic matter in black shales from both environments is type II and has good potential for generation of liquid hydrocarbons during catagenesis.

  10. Evaluating Renewable Cornstarch/biochar Fillers as Potential Substitutes for Carbon Black in SBR Composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The continually growing demand for fossil fuels coupled with the potential risk of relying on foreign sources for these fuels strengthens the need to find renewable substitutes for petroleum products. Carbon black is a petroleum product that dominates the rubber composite filler market. Agricultur...

  11. Preparation of yellowish-red Al-substituted ?-Fe2O3 powders and their thermostability in color.

    PubMed

    Hashimoto, Hideki; Nakanishi, Makoto; Asaoka, Hiroshi; Maeda, Tomoaki; Kusano, Yoshihiro; Fujii, Tatsuo; Takada, Jun

    2014-11-26

    Inspired by the traditional Japanese pigment Fukiya bengala, nanocomposite materials were synthesized using a polymer complex method, comprising Al-substituted ?-Fe2O3 (hematite) particles with diameters ranging from 40 to 100 nm and ultrafine Fe-substituted ?-Al2O3 (corundum) particles smaller than 10 nm in diameter. The obtained powders exhibited a vivid yellowish-red color and high thermostability, making them attractive as potential overglaze enamels on porcelain. Quantitative color measurements revealed that, when heated to 700, 800, and 900 °C, samples displayed high lightness (L*) and color-opponent dimensions (a* and b*) at 10 mol % Al. For the same particle size samples, L*, a*, and b* values increased with the Al molar ratio, revealing that Al substitution in the hematite structure intrinsically enhances lightness and chroma in hematite color. These samples mostly retained their color upon reheating at 900 °C, indicating their high thermostability. This thermostability should originate from the Al substitution-induced enhancement in lightness and chroma in hematite color, which should counter color fading caused by particle growth. These composite materials are expected to find application in the porcelain industry, cosmetics, and nanotechnology. PMID:25313688

  12. Structure, Stoichiometry, and Phase Purity of Calcium Substituted Lanthanum Manganite Powders

    Microsoft Academic Search

    S. Faaland; K. D. Knudsen; M.-A. Einarsrud; L. Rørmark; R. Høier; T. Grande

    1998-01-01

    Calcium-doped lanthanum manganite La1?xCaxMnO3, synthesized by the glycine\\/nitrate method, was characterized by high resolution synchrotron X-ray powder diffraction, electron diffraction, and infrared spectroscopy. A strong correlation was observed between the cooling rate from the calcination temperature and the powder quality, indicating the importance of a homogeneous oxygen stoichiometry. The structure refinement reveals that La1?xCaxMnO3withx=0.2, 0.3, 0.4, and 0.6 has orthorhombic

  13. A study of Sm-substituted SrM magnets sintered using hydrothermally synthesised powders

    NASA Astrophysics Data System (ADS)

    Wang, J. F.; Ponton, C. B.; Harris, I. R.

    2006-03-01

    Anisotropic SrM magnets with Sm substitution, which is observed to have the largest beneficial effect both on the coercivity and on the inhibition of grain growth at high temperature among the other elements such as La, Nd and Pr, were investigated. The average grain size of the samples decreases with increasing Sm/Sr ratio. All the magnets with Sm additions exhibit a bigger coercivity and remanence than those of the SrM magnet without Sm and the coercivity of the magnets increases with increasing Sm/Sr ratio. EDX quantitative analysis suggests that the solubility of Sm 3+ in the SrM-type structure is very small and that the Sm 3+ preferably goes into SrFeO 3-x, which is probably located around the SrM grain boundaries. The coercivity mechanism of the magnets is nucleation controlled. The formation and the distribution of the SrFeO 3-x phase around the SrM grain boundraies probably provides the inhibition of SrM grain growth, the reduction of the reverse domain nucleation at the grain surface and the isolation of the SrM grains. All these factors would contribute to the improvements of the coercivity of the magnets with Sm additions.

  14. Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

    PubMed

    Clack, Herek L

    2012-07-01

    The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions. PMID:22663136

  15. Influence of setting liquid composition and liquid-to-powder ratio on properties of a Mg-substituted calcium phosphate cement.

    PubMed

    Pina, S; Olhero, S M; Gheduzzi, S; Miles, A W; Ferreira, J M F

    2009-05-01

    The influence of four variables on various properties of a Mg-substituted calcium phosphate cement (CPC) was investigated. The variables were the heat treatment temperature of the precipitated powders, the composition of the setting liquid, the liquid-to-powder ratio (LPR), and the time over which hardened specimens were cured in air. The properties analysed were the phase composition of the starting powder, the initial setting time, the evolution of the storage shear modulus (G') and the loss shear modulus (G'') with the cement paste curing time (t), and the compressive strength. The presence of alpha-TCP in CPC facilitated the setting and hardening properties due to its progressive dissolution and the formation of brushite crystals. As far as the liquid composition is concerned, in cases where citric acid was used, adding a rheology modifier (10 wt.% polyethylene glycol or 0.5 wt.% hydroxyl propylmethylcellulose) to the acid led to an increase in the initial setting time, while an increase in the acid concentration led to a decrease in the initial setting time. The initial setting time showed to be very sensitive towards the LPR. The evolution of G' and G'' with curing time reflected the internal structural changes of cement pastes during the setting process. The compressive strength of the wet-hardened cement specimens with and without Mg increased with curing time increasing, being slightly higher in the case of Mg-substituted CPC. The results suggest that Mg-substituted CPC holds a promise for uses in orthopaedic and trauma surgery such as for filling bone defects. PMID:19121609

  16. Magnetic properties of Ce-substituted yttrium iron garnet ferrite powders fabricated using a sol-gel method

    Microsoft Academic Search

    Jun Sig Kum; Sam Jin Kim; In-Bo Shim; Chul Sung Kim

    2004-01-01

    Y2.9Ce0.1Fe5O12 powders which were annealed above 1200°C had only a single phase garnet cubic structure and showed ferrimagnetic behaviors. Powders annealed below 1200°C had mixed phases of garnet, alpha-Fe2O3, and YFeO3 structures. The magnetic behavior of Y2.9Ce0.1Fe5O12 powders annealed above 800°C showed that an increase of the annealing temperature yielded decrease in the coercivity; however, opposite tendency was shown in

  17. Magnetic properties of Ce-substituted yttrium iron garnet ferrite powders fabricated using a sol–gel method

    Microsoft Academic Search

    Jun Sig Kum; Sam Jin Kim; In-Bo Shim; Chul Sung Kim

    2004-01-01

    Y2.9Ce0.1Fe5O12 powders which were annealed above 1200°C had only a single phase garnet cubic structure and showed ferrimagnetic behaviors. Powders annealed below 1200°C had mixed phases of garnet, ?-Fe2O3, and YFeO3 structures. The magnetic behavior of Y2.9Ce0.1Fe5O12 powders annealed above 800°C showed that an increase of the annealing temperature yielded decrease in the coercivity; however, opposite tendency was shown in

  18. Large scale production of yolk-shell ?-tricalcium phosphate powders, and their bioactivities as novel bone substitutes.

    PubMed

    Cho, Jung Sang; Lee, Jong-Heun; Kang, Yun Chan

    2014-08-28

    This paper proposes the production of yolk-shell structured ?-tricalcium phosphate (?-TCP) powders using a spray-drying method, suitable for commercial scale production. Spray-dried precursor powders, consisting of calcium-phosphate salts and each of the various carbon source materials, are combusted in an oxygen atmosphere to obtain a yolk-shell structure. Only dextrin among the carbon source materials investigated shows promise in the production of ?-TCP yolk-shell powders. By evaluating their apatite-forming capacity in simulated body fluid, the outstanding bioactivity of ?-TCP yolk-shell powders is confirmed: numerous acicular and newly formed hydroxyl carbonate apatite crystals cover the entire ?-TCP surface after a single day of soaking. These crystals are observed on both the outer and inner surfaces of the shells, and on the outer surface of the core, which is encouraging for its potential use as a bone grafting material. PMID:25005151

  19. Synthesis of Black and Red Mercury Sulfide Nano-Powder by Traditional Indian Method for Biomedical Application

    NASA Astrophysics Data System (ADS)

    Padhi, Payodhar; Sahoo, G.; Das, K.; Ghosh, Sudipto; Panigrahi, S. C.

    2008-10-01

    The use of metals and minerals in the traditional Indian system of medicine known as aired is very common and is practiced since seventh century B.C. Metals were reduced to calcined powder form for medicinal purpose. For detoxification, a further step of purification of the metals and minerals with different vegetable extracts was practiced. The people of East India were using mercury and its sulfide as medicine. Gradually this secret was leaked to Arabic physicians who used mercury in skin ointment. Subsequently Italian Physicians adopted Arabic prescriptions of mercurial ointments for skin diseases. In the olden days, metals and minerals were impregnated with decoction and juice of vegetables and animal products like milk and fat for purification. These were then reduced to fine particles by milling with a pestle and mortar. It was known by then that the fineness of the powder had a significant influence on the color, texture, and medicinal properties as is cited by Charak. Nagarjun studied in detail the processing of metals and minerals, particularly mercury and the influence of the processing parameters on the medicinal values. Mercury is unique in many aspects. Indian alchemy developed a wide variety a chemical processes for the ostensible transmutation of metals and preparation of elixir of life, in which mercury occupied a prime position .The present investigation attempts to use the traditional methods as prescribed in the ancient texts to prepare mercury sulfide in both red and black form for medicinal use. XRD, SEM and HRTEM investigations of the sulfides obtained shows that the ancient Indians were able to produce nano-sized powders. Possibly this may be taken as the earliest application of the production and use of nano powder. The study proves that even in ancient time the knowledge of nano particle synthesis was prevalent and used to enhance effectiveness of medicines. Further mercury in the free form is not acceptable in medicines. The ancient physicians could get rid of free mercury by milling and proper choice of the ratio of ingredients as is shown in the investigation by X-ray diffraction studies. In the traditional method for synthesis of mercury sulfide, mercury and pure sulfur were taken and milled in a mortar and pastel. During milling process, the white mercury and yellow sulfur yielded to a gray black colored sulfide. Synthesis of red sulfide of mercury required additional steps of heating and subsequent milling. For therapeutically application, the sulfide thus obtained needed detoxification, which was done using organic extracts. In the present investigation, the same method was followed to synthesize the sapphires and the product was characterized using modern methods like XRD, SEM and HRTEM. With increase in milling time the fineness of the powder increases, which increases the efficacy of the medicine, and free mercury, which is not desirable for medicinal application is found to decrease. The powder obtained at the end of 48 hours of milling is found to be of a size finer than l0nm.

  20. N vacancy, substitutional O, and Al defects in the bandgap of composition-tunable nonstoichiometric AlN powder

    NASA Astrophysics Data System (ADS)

    Zhang, Dian; Liu, Fa-Min; Cai, Lu-Gang

    2014-06-01

    AlN powders are prepared by direct nitridation via Al liquid and vapor phases in mixed atmospheres of N2 and NH3 with different NH3/N2 ratios. The reaction analysis reveals that NH3 acts as catalyst for N2 dissociation and the transportations of N, O, and Al in the liquid phase are different from those in the vapor phase. Accordingly, the products are Al-rich and composition-tunable nonstoichiometric AlN in which N, O, and Al content values change with nitridation atmosphere and temperature, leading to the variation of the relevant defect concentration. Therefore, the AlN powders exhibit prominent absorption bands around 5.30, 3.40, and 1.50 eV, which are tentatively assigned to VN, ON donors, and AlN acceptor respectively. Furthermore, a new donor named [VN—ON] complex is predicted at 4.40 eV within the 5.90 eV bandgap. It is demonstrated that the optical spectra of nonstoichiometric AlN are preferable to the nominal stoichimometric one for the identification of the defects energy level.

  1. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...substituted] phenyl- modified, sodium salts (generic). 721.10075 Section 721...substituted] phenyl- modified, sodium salts (generic). (a) Chemical substance...substituted] phenyl-modified, sodium salts (PMN P-05-722) is subject to...

  2. 40 CFR 721.10075 - Carbon black, 4-[[2-(Sulfooxy) ethyl]substituted] phenyl- modified, sodium salts (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...substituted] phenyl- modified, sodium salts (generic). 721.10075 Section 721...substituted] phenyl- modified, sodium salts (generic). (a) Chemical substance...substituted] phenyl-modified, sodium salts (PMN P-05-722) is subject to...

  3. Hole doping by Li substitution and antiferromagnetism in YBa Cu O studied by neutron powder diffraction measurements

    NASA Astrophysics Data System (ADS)

    Maury, F.; Mirebeau, I.; Nicolas-Francillon, M.; Bourée, F.

    2002-06-01

    The magnetic structure of tetragonal insulating YBa2Cu3-xLixOy has been studied as a function of x and y. The Néel temperature and the mean ordered magnetic moment on the Cu2 sites were determined by neutron powder diffraction measurements. The decrease of these two parameters as compared to YBa2Cu3O6 is much stronger for lithium than for zinc substitution. The difference is quantitatively explained by the presence of holes created in the CuO2 planes. These holes arise from the substitution of plane Cu2+ by Li+. We suggest an explanation why such holes are not seen for the same substitution of plane Cu2+ by Li+ in orthorhombic superconducting YBa2Cu3-xLixO 7 - ?.

  4. Effect of Cu{sup 2+} and Ni{sup 2+} substitution at the Mn site in (La{sub 0.63}Ca{sub 0.37})MnO{sub 3}: A neutron powder diffraction investigation

    SciTech Connect

    Martinelli, A., E-mail: alberto.martinelli@spin.cnr.it [CNR-SPIN, C.so Perrone 24, 16152 Genova (Italy); Ferretti, M. [CNR-SPIN, C.so Perrone 24, 16152 Genova (Italy); Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Castellano, C. [Università degli Studi di Milano, Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Via G. Venezian 21, 20133 Milano (Italy); Cimberle, M.R. [IMEM-CNR, Via Dodecaneso 33, 16146 Genova (Italy); Ritter, C. [Institute Laue—Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France)

    2013-04-15

    The crystal and magnetic structures of the (La{sub 0.63}Ca{sub 0.37})(Mn{sub 1?x}TM{sub x})O{sub 3} compounds (x=0.00, 0.03, 0.08; TM=Cu{sup 2+}, Ni{sup 2+}) were investigated between 5 K and 300 K by means of dc magnetic measurements and neutron powder diffraction analysis followed by Rietveld refinement. Both substituting cations lead to a reduction of the long range ferromagnetic ordering temperature; ferromagnetism is strongly suppressed in the 8% Cu-substituted sample, where long- and short-range FM magnetic orders coexist together with short-range A-type AFM order. This particular feature can be related to the Jahn–Teller character of Cu{sup 2+}, absent in Ni{sup 2+}, and suggests the occurrence of a quantum critical point in the (La{sub 0.63}Ca{sub 0.37})(Mn{sub 1?x}Cu{sub x})O{sub 3} system. - Graphical abstract: Rietveld refinement plot of (La{sub 0.63}Ca{sub 0.37})(Mn{sub 0.92}Cu{sub 0.08})O{sub 3} showing in the inset the coexistence of broad A-type AFM peaks with FM ones. Highlights: ? (La{sub 0.63}Ca{sub 0.37})MnO{sub 3} was substituted with Ni and Cu. ? Neutron powder diffraction and Rietveld refinement were carried out. ? A quantum critical point possibly occurs in the (La{sub 0.63}Ca{sub 0.37})(Mn{sub 1?x}Cu{sub x})O{sub 3} system.

  5. Fatal contact shot to the chest caused by the gas jet from a muzzle-loading pistol discharging only black powder and no bullet: case study and experimental simulation of the wounding effect.

    PubMed

    Große Perdekamp, Markus; Glardon, Matthieu; Kneubuehl, Beat P; Bielefeld, Lena; Nadjem, Hadi; Pollak, Stefan; Pircher, Rebecca

    2015-01-01

    In modern medico-legal literature, only a small number of publications deal with fatal injuries from black powder guns. Most of them focus on the morphological features such as intense soot soiling, blast tattooing and burn effects in close-range shots or describe the wound ballistics of spherical lead bullets. Another kind of "unusual" and potentially lethal weapons are handguns destined for firing only blank cartridges such as starter and alarm pistols. The dangerousness of these guns is restricted to very close and contact range shots and results from the gas jet produced by the deflagration of the propellant. The present paper reports on a suicide committed with a muzzle-loading percussion pistol cal. 45. An unusually large stellate entrance wound was located in the precordial region, accompanied by an imprint mark from the ramrod and a faint greenish discoloration (apparently due to the formation of sulfhemoglobin). Autopsy revealed an oversized powder cavity, multiple fractures of the anterior thoracic wall as well as ruptures of the heart, the aorta, the left hepatic lobe and the diaphragm. In total, the zone of mechanical destruction had a diameter of approx. 15 cm. As there was no exit wound and no bullet lodged in the body, the injury was caused exclusively by the inrushing combustion gases of the propellant (black powder) comparable with the gas jet of a blank cartridge gun. In contact shots to ballistic gelatine using the suicide's pistol loaded with black powder but no projectile, the formation of a nearly spherical cavity could be demonstrated by means of a high-speed camera. The extent of the temporary cavity after firing with 5 g of black powder roughly corresponded to the zone of destruction found in the suicide's body. PMID:25119685

  6. Improving the electrical conductivity by forming Ni powder chains in a shape-memory polymer filled with carbon black

    NASA Astrophysics Data System (ADS)

    Lan, Xin; Huang, Wei Min; Liu, Na; Phee, Sy; Leng, Jin Song; Du, Shan Yi

    2008-03-01

    We demonstrate a simple approach to significantly reduce the electrical resistivity of thermo-responsive shape-memory polymers (SMPs), so that they can be easily triggered for shape recovery by Joule heating at a low electrical voltage. After adding a small amount of Ni micro particles into a polyurethane SMP filled with carbon black (CB), the electrical resistivity is slightly reduced. However, if these Ni particles are aligned into chains (by applying a low magnetic field on SMP/CB/Ni solution and then drying to fix the conductive chains), the drop of electrical resistivity is significant. This kind of SMP composites is suitable for cyclic operation as only micro/nano particles are used. A sample (40×15×1mm) with 10vol% of CB and 0.5vol% of chained Ni can be heated to 80°C for shape recovery at 30 V (1.2 W) of power. This approach is generic and applicable for producing other conductive polymers.

  7. Cheap, Gram-Scale Fabrication of BN Nanosheets via Substitution Reaction of Graphite Powders and Their Use for Mechanical Reinforcement of Polymers

    PubMed Central

    Liu, Fei; Mo, Xiaoshu; Gan, Haibo; Guo, Tongyi; Wang, Xuebin; Chen, Bin; Chen, Jun; Deng, Shaozhi; Xu, Ningsheng; Sekiguchi, Takashi; Golberg, Dmitri; Bando, Yoshio

    2014-01-01

    As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5?nm to 40?nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300?nm to 500?nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56?GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials. PMID:24572725

  8. Effects of Black Pepper (Piper Nigrum), Turmeric Powder (Curcuma Longa) and Coriander Seeds (Coriandrum Sativum) and Their Combinations as Feed Additives on Growth Performance, Carcass Traits, Some Blood Parameters and Humoral Immune Response of Broiler Chickens

    PubMed Central

    Abou-Elkhair, R.; Ahmed, H. A.; Selim, S.

    2014-01-01

    Different herbs and spices have been used as feed additives for various purposes in poultry production. This study was conducted to assess the effect of feed supplemented with black pepper (Piper nigrum), turmeric powder (Curcuma longa), coriander seeds (Coriandrum sativum) and their combinations on the performance of broilers. A total of 210 (Cobb) one-d-old chicks were divided into seven groups of 30 birds each. The treatments were: a control group received no supplement, 0.5% black pepper (T1), 0.5% turmeric powder (T2), 2% coriander seeds (T3), a mixture of 0.5% black pepper and 0.5% turmeric powder (T4), a mixture of 0.5% black pepper and 2% coriander seed (T5), and a mixture of 0.5% black pepper, 0.5% turmeric powder and 2% coriander seeds (T6). Higher significant values of body weight gain during the whole period of 5 weeks (p<0.001) were observed in broilers on T1, T3, T5, and T6 compared to control. Dietary supplements with T1, T2, T3, and T6 improved the cumulative G:F of broilers during the whole period of 5 weeks (p<0.001) compared with control. The dressing percentage and edible giblets were not influenced by dietary supplements, while higher values of relative weight of the liver (p<0.05) were obtained in T5 and T6 compared to control. The addition of feed supplements in T5 and T6 significantly increased serum total protein and decreased serum glucose, triglycerides and alkaline phosphatase concentrations compared with the control group (p<0.05). Broilers on T6 showed significant decrease in the serum glutamate pyruvate transaminase concentration (p<0.05) compared to control. The broilers having T5 and T6 supplemented feed had relatively greater antibody titre (p<0.001) at 35 d of age than control. It is concluded that dietary supplements with black pepper or coriander seeds or their combinations enhanced the performance and health status of broiler chickens. PMID:25050023

  9. Effects of black pepper (piper nigrum), turmeric powder (curcuma longa) and coriander seeds (coriandrum sativum) and their combinations as feed additives on growth performance, carcass traits, some blood parameters and humoral immune response of broiler chickens.

    PubMed

    Abou-Elkhair, R; Ahmed, H A; Selim, S

    2014-06-01

    Different herbs and spices have been used as feed additives for various purposes in poultry production. This study was conducted to assess the effect of feed supplemented with black pepper (Piper nigrum), turmeric powder (Curcuma longa), coriander seeds (Coriandrum sativum) and their combinations on the performance of broilers. A total of 210 (Cobb) one-d-old chicks were divided into seven groups of 30 birds each. The treatments were: a control group received no supplement, 0.5% black pepper (T1), 0.5% turmeric powder (T2), 2% coriander seeds (T3), a mixture of 0.5% black pepper and 0.5% turmeric powder (T4), a mixture of 0.5% black pepper and 2% coriander seed (T5), and a mixture of 0.5% black pepper, 0.5% turmeric powder and 2% coriander seeds (T6). Higher significant values of body weight gain during the whole period of 5 weeks (p<0.001) were observed in broilers on T1, T3, T5, and T6 compared to control. Dietary supplements with T1, T2, T3, and T6 improved the cumulative G:F of broilers during the whole period of 5 weeks (p<0.001) compared with control. The dressing percentage and edible giblets were not influenced by dietary supplements, while higher values of relative weight of the liver (p<0.05) were obtained in T5 and T6 compared to control. The addition of feed supplements in T5 and T6 significantly increased serum total protein and decreased serum glucose, triglycerides and alkaline phosphatase concentrations compared with the control group (p<0.05). Broilers on T6 showed significant decrease in the serum glutamate pyruvate transaminase concentration (p<0.05) compared to control. The broilers having T5 and T6 supplemented feed had relatively greater antibody titre (p<0.001) at 35 d of age than control. It is concluded that dietary supplements with black pepper or coriander seeds or their combinations enhanced the performance and health status of broiler chickens. PMID:25050023

  10. Mystery Powders

    NSDL National Science Digital Library

    American Chemical Society

    2000-01-01

    In this activity on page 2 of the PDF, learners conduct chemical tests on certain powders used in cooking. After completing the tests, learners try to figure out the identity of a mystery powder. Learners record their observations on a chart. Note: you will need an adult helper for this activity.

  11. Magnetic properties of substituted barium ferrite powders

    SciTech Connect

    Gruskova, A. [Slovak Univ. of Technology, Bratislava (Slovakia). Dept. of Electrotechnology] [Slovak Univ. of Technology, Bratislava (Slovakia). Dept. of Electrotechnology

    1994-03-01

    Hexagonal barium ferrites were prepared using the citrate method. Cobalt and titanium were added in the amounts x from 0.2 to 1.1 ion/f.u. related to the formula BaCo{sub x}Ti{sub x}Fe{sub 12{minus}2x}O{sub 19}. The heat treatment has been applied in three steps of 550 C/5 hrs, 850 C/2 hrs and 1,100 C/2 hrs. The following magnetic properties have been achieved: H{sub c} {approximately} 80 kA/m, J{sub s} {approximately} 120 {times} 10{sup {minus}6} Tkg{sup {minus}1} m{sup 3}, and J{sub r} {approximately} 60 {times} 10{sup {minus}6} Tkg{sup {minus}1} m{sup 3} in the composition for which x is equal to 0.5 ion/f.u. The magnetic parameters have been measured by the vibration magnetometer.

  12. Powder Particulars

    NSDL National Science Digital Library

    2012-04-08

    In this introductory activity and demonstration, learners are introduced to the concept that different substances react chemically in characteristic ways. First learners compare the way baking soda and baking powder react with vinegar. Then they see dramatic color changes when red cabbage indicator is added to cream of tartar and laundry detergent. From this, learners are ready to identify unknown powders based on their reactive properties.

  13. Photocatalytic degradation of dye naphthol blue black in the presence of zirconia-supported Ti-substituted Keggin-type polyoxometalates

    SciTech Connect

    Jiang Chunjie; Guo Yihang; Hu Changwen; Wang Chungang; Li Danfeng

    2004-02-02

    Zirconia-supported Ti-substituted Keggin-type polyoxometalates, Li{sub 5}PW{sub 11}TiO{sub 40}/ZrO{sub 2} (PW{sub 11}Ti/ZrO{sub 2}) and K{sub 7}PW{sub 10}Ti{sub 2}O{sub 40}/ZrO{sub 2} (PW{sub 10}Ti{sub 2}/ZrO{sub 2}), were prepared by incorporating PW{sub 11}Ti and PW{sub 10}Ti{sub 2} cluster into a zirconia matrix via a sol-gel technique. These insoluble and readily separable composites were characterized by DR-UV (DR: diffuse reflectance) and FT-IR spectra, {sup 31}P MAS NMR, ICP-AES, and nitrogen adsorption determination, indicating that the clusters were chemically attached to the zirconia supports, and the primary Keggin structure remained intact. The photocatalytic activity of the supported PW{sub 11}Ti and PW{sub 10}Ti{sub 2} was tested via degradation of an aqueous dye naphthol blue black (NBB). It indicated that the dye NBB can be degraded totally and mineralized into the inorganic products such as CO{sub 2}, NH{sub 4}{sup +}, NO{sub 3}{sup -}, and SO{sub 4}{sup 2-} ions by irradiating the composite slurry in the near-UV area. Dropped of PW{sub 11}Ti or PW{sub 10}Ti{sub 2} cluster from the zirconia matrix into the reaction system was hardly observed during the photocatalytic tests, attributed to the strong chemical interactions between the Keggin units and the zirconia support.

  14. Hot-gas ignition of powders

    Microsoft Academic Search

    V. E. Zarko; V. F. Mikheev; A. I. Sukhinin; S. S. Khlevnoi

    1971-01-01

    In this paper we present the results of a study of the ignition of pyroxylin No. 1 and nitroglycerine powder (N powder) containing 1% carbon black by a hot gas. The gas was heated by a piece of tungsten foil (50 # thick, area 10  45 ram) parallel to the surface of the sample (Fig. 1). The foil was

  15. Chemical characterization of some substituted hydroxyapatites

    PubMed Central

    2011-01-01

    Synthetic multi-substituted hydroxyapatite nano powders containing silicon and or carbonate prepared by a wet chemical method. The process parameters are set up to allow the simultaneous substitution of carbonate and silicon ions in the place of phosphorus. The chemical and structural characterizations of the prepared powders are determined with the aid of; XRF, ICP, XRD and FTIR. The results show that, the ion substitution in the crystal lattice of HA caused a change in the unit cell dimensions and affected the degree of crystallization of the produced powders. The apatite formation abilityy of the prepared discs from the synthesized powders is determined by immersing in SBF solution for different periods. The degree of ion release was determined in the obtained solutions. The examined surface of the immersed discs under SEM and analyzed by CDS showed a more dense HA layer than those of un-substituted ones. The HA with the substituted silicon and carbonate ions, showed the highest solubility with greater rate of ion release, compared with carbonate-free powder. All prepared powders took sodium ion from the SBF solution during immersion, which was not recorded before. PMID:22122971

  16. Skin Substitutes

    PubMed Central

    Howe, Nicole; Cohen, George

    2014-01-01

    In a relatively short timespan, a wealth of new skin substitutes made of synthetic and biologically derived materials have arisen for the purpose of wound healing of various etiologies. This review article focuses on providing an overview of skin substitutes including their indications, contraindications, benefits, and limitations. The result of this overview was an appreciation of the vast array of options available for clinicians, many of which did not exist a short time ago. Yet, despite the rapid expansion this field has undergone, no ideal skin substitute is currently available. More research in the field of skin substitutes and wound healing is required not only for the development of new products made of increasingly complex biomolecular material, but also to compare the existing skin substitutes. PMID:25371771

  17. Energetic powder

    DOEpatents

    Jorgensen, Betty S. (Jemez Springs, NM); Danen, Wayne C. (Los Alamos, NM)

    2003-12-23

    Fluoroalkylsilane-coated metal particles. The particles have a central metal core, a buffer layer surrounding the core, and a fluoroalkylsilane layer attached to the buffer layer. The particles may be prepared by combining a chemically reactive fluoroalkylsilane compound with an oxide coated metal particle having a hydroxylated surface. The resulting fluoroalkylsilane layer that coats the particles provides them with excellent resistance to aging. The particles can be blended with oxidant particles to form energetic powder that releases chemical energy when the buffer layer is physically disrupted so that the reductant metal core can react with the oxidant.

  18. Influence of moisture content on inactivation of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium in powdered red and black pepper spices by radio-frequency heating.

    PubMed

    Jeong, Seul-Gi; Kang, Dong-Hyun

    2014-04-17

    The influence of moisture content during radio-frequency (RF) heating on heating rate, dielectric properties, and inactivation of foodborne pathogens was investigated. The effect of RF heating on the quality of powdered red and black pepper spices with different moisture ranges was also investigated. Red pepper (12.6%, 15.2%, 19.1%, and 23.3% dry basis, db) and black pepper (10.1%, 17.2%, 23.7%, and 30.5% db) inoculated with Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium were treated in a RF heating system with 27.12 MHz. The heating rate of the sample was dependent on moisture content up to 19.1% (db) of red pepper and 17.2% (db) of black pepper, but there was a significant decrease in the heating rate when the moisture content was increased beyond these levels. The dielectric properties of both samples increased with a rise in moisture content. As the moisture content increased, treatment time required to reduce E. coli O157:H7 and S. Typhimurium by more than 7 log CFU/g (below the detection limit, 1 log CFU/g) decreased and then increased again without affecting product quality when the moisture content exceeded a level corresponding to the peak heating rate. RF treatment significantly (P<0.05) reduced moisture content of both spices. These results suggest that RF heating can be effectively used to not only control pathogens but also reduce moisture levels in spices and that the effect of inactivation is dependent on moisture content. PMID:24555992

  19. X-ray powder diffraction, vibration and thermal studies of [A{sub 0.92}(NH{sub 4}){sub 0.08}]{sub 2}TeCl{sub 4}Br{sub 2} with A = Cs, Rb: Influence of mixed cationic and anionic substitutions

    SciTech Connect

    Aribia, W. Ben; Abdelmouleh, M. [Laboratoire des Sciences des Materiaux et de l'environnement, Universite de Sfax, Faculte des Sciences de Sfax, 3018 (Tunisia)] [Laboratoire des Sciences des Materiaux et de l'environnement, Universite de Sfax, Faculte des Sciences de Sfax, 3018 (Tunisia); Kabadou, A., E-mail: kabadouahlem@yahoo.fr [Laboratoire des Sciences des Materiaux et de l'environnement, Universite de Sfax, Faculte des Sciences de Sfax, 3018 (Tunisia); Van Der Lee, A. [Institut Europeen des Membranes (UMR 5635), Universite de Montpellier II, cc 047, Place E. Montpellier (France)] [Institut Europeen des Membranes (UMR 5635), Universite de Montpellier II, cc 047, Place E. Montpellier (France)

    2012-05-15

    Graphical abstract: The structures of [A{sub 0.92}(NH{sub 4}){sub 0.08}]{sub 2}TeCl{sub 4}Br{sub 2} with A = Cs, Rb belong to the tetragonal {beta}-K{sub 2}SnCl{sub 6} structure type. Highlights: Black-Right-Pointing-Pointer The two new compound crystallises in P4/mnc tetragonal space group. Black-Right-Pointing-Pointer The structure is considered as isolated octahedred TeCl{sub 4}Br{sup 2-}. Black-Right-Pointing-Pointer The octahedra connected by ionic and hydrogen bonding through the Cs/Rb or N atoms. Black-Right-Pointing-Pointer A DTA/TGA experiment reveals one endothermic peak at 780 K for these compounds. Black-Right-Pointing-Pointer One endothermic peak is detected at around 213 K by DSC experiment. -- Abstract: The crystal structures of [A{sub 0.92}(NH{sub 4}){sub 0.08}]{sub 2}TeCl{sub 4}Br{sub 2} with A = Cs, Rb have been determined using X-ray powder diffraction techniques. The two compounds crystallize in the tetragonal space group P4/mnc, with the unit cell parameters: a = 7.452(1) Angstrom-Sign , c = 10.544(3) Angstrom-Sign , Z = 2 and a = 7.315(2) Angstrom-Sign , c = 10.354(4) Angstrom-Sign , Z = 2 in the presence of Cs and Rb, respectively. These two compounds have an antifluorite-type arrangement of NH{sub 4}{sup +}/Rb{sup +}/Cs{sup +} and octahedral TeCl{sub 4}Br{sub 2}{sup 2-} anions. The stability of these structure is by ionic and hydrogen bonding contacts: A Midline-Horizontal-Ellipsis Cl, A Midline-Horizontal-Ellipsis Br and N-H Midline-Horizontal-Ellipsis Cl, N-H Midline-Horizontal-Ellipsis Br. The different vibrational modes of these powders were analysed by FTIR and Raman spectroscopic studies. A DTA/TGA experiment reveals one endothermic peak at 780 K implicating the decomposition of the sample. At low temperature, one endothermic peak in thermal behavior is detected at around 213 K by DSC experiment. This transition was confirmed by dielectric measurements.

  20. Pinwheel patterns and powder diffraction

    E-print Network

    Michael Baake; Dirk Frettlöh; Uwe Grimm

    2006-10-06

    Pinwheel patterns and their higher dimensional generalisations display continuous circular or spherical symmetries in spite of being perfectly ordered. The same symmetries show up in the corresponding diffraction images. Interestingly, they also arise from amorphous systems, and also from regular crystals when investigated by powder diffraction. We present first steps and results towards a general frame to investigate such systems, with emphasis on statistical properties that are helpful to understand and compare the diffraction images. We concentrate on properties that are accessible via an alternative substitution rule for the pinwheel tiling, based on two different prototiles. Due to striking similarities, we compare our results with the toy model for the powder diffraction of the square lattice.

  1. Monoalphabetic Substitution

    NSDL National Science Digital Library

    O\\'Bryant, Kevin

    This applet, created by Kevin O'Bryant of the University of California - San Diego, illustrates the monoalphabetic substitution codebreaking process using a chi-squared process. The author explains how and why this encryption method is used. Overall, it is a wonderful example of how probability and statistics can be applied to real world situations.

  2. Solvent substitution

    SciTech Connect

    Not Available

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  3. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it`s usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  4. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it's usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  5. Characterization of Fine Powders

    NASA Astrophysics Data System (ADS)

    Krantz, Matthew; Zhang, Hui; Zhu, Jesse

    Fine powders are used in many applications and across many industries such as powdered paints and pigments, ceramics, petrochemicals, plastics, pharmaceuticals, and bulk and fine chemicals, to name a few. In addition, fine powders must often be handled as a waste by-product, such as ash generated in combustion and gasification processes. In order to correctly design a process and process equipment for application and handling of powders, especially fine powders, it is essential to understand how the powder would behave. Many characterization techniques are available for determining the flow properties of powders; however, care must be taken in selecting the most appropriate technique(s).

  6. Preparation of titanium diboride powder

    DOEpatents

    Brynestad, Jorulf (Oak Ridge, TN); Bamberger, Carlos E. (Oak Ridge, TN)

    1985-01-01

    Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

  7. Substitute Teachers

    NSDL National Science Digital Library

    C. Jill Swango

    2003-01-01

    Our lives are ones of uncertainty and surprise, yin and yang existences. Some things we can control and others we are powerless to command, even with the best intentions. Teachers are not exempt from emergencies, jury duty, and illness. Luckily, most schools plan for such incidents by having willing substitutes on hand. Teachers need to follow the Scout's motto to "be prepared" and keep the classroom running smoothly and efficiently for students and subs.

  8. Composite powder particles

    NASA Technical Reports Server (NTRS)

    Parker, Donald S. (Inventor); MacDowell, Louis G. (Inventor)

    2009-01-01

    A liquid coating composition including a coating vehicle and composite powder particles disposed within the coating vehicle. Each composite powder particle may include a magnesium component, a zinc component, and an indium component.

  9. Aluminum powder metallurgy processing

    SciTech Connect

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  10. Dustiness of Fine and Nanoscale Powders

    PubMed Central

    Evans, Douglas E.; Baron, Paul A.

    2013-01-01

    Dustiness may be defined as the propensity of a powder to form airborne dust by a prescribed mechanical stimulus; dustiness testing is typically intended to replicate mechanisms of dust generation encountered in workplaces. A novel dustiness testing device, developed for pharmaceutical application, was evaluated in the dustiness investigation of 27 fine and nanoscale powders. The device efficiently dispersed small (mg) quantities of a wide variety of fine and nanoscale powders, into a small sampling chamber. Measurements consisted of gravimetrically determined total and respirable dustiness. The following materials were studied: single and multiwalled carbon nanotubes, carbon nanofibers, and carbon blacks; fumed oxides of titanium, aluminum, silicon, and cerium; metallic nanoparticles (nickel, cobalt, manganese, and silver) silicon carbide, Arizona road dust; nanoclays; and lithium titanate. Both the total and respirable dustiness spanned two orders of magnitude (0.3–37.9% and 0.1–31.8% of the predispersed test powders, respectively). For many powders, a significant respirable dustiness was observed. For most powders studied, the respirable dustiness accounted for approximately one-third of the total dustiness. It is believed that this relationship holds for many fine and nanoscale test powders (i.e. those primarily selected for this study), but may not hold for coarse powders. Neither total nor respirable dustiness was found to be correlated with BET surface area, therefore dustiness is not determined by primary particle size. For a subset of test powders, aerodynamic particle size distributions by number were measured (with an electrical low-pressure impactor and an aerodynamic particle sizer). Particle size modes ranged from approximately 300nm to several micrometers, but no modes below 100nm, were observed. It is therefore unlikely that these materials would exhibit a substantial sub-100nm particle contribution in a workplace. PMID:23065675

  11. Dustiness of fine and nanoscale powders.

    PubMed

    Evans, Douglas E; Turkevich, Leonid A; Roettgers, Cynthia T; Deye, Gregory J; Baron, Paul A

    2013-03-01

    Dustiness may be defined as the propensity of a powder to form airborne dust by a prescribed mechanical stimulus; dustiness testing is typically intended to replicate mechanisms of dust generation encountered in workplaces. A novel dustiness testing device, developed for pharmaceutical application, was evaluated in the dustiness investigation of 27 fine and nanoscale powders. The device efficiently dispersed small (mg) quantities of a wide variety of fine and nanoscale powders, into a small sampling chamber. Measurements consisted of gravimetrically determined total and respirable dustiness. The following materials were studied: single and multiwalled carbon nanotubes, carbon nanofibers, and carbon blacks; fumed oxides of titanium, aluminum, silicon, and cerium; metallic nanoparticles (nickel, cobalt, manganese, and silver) silicon carbide, Arizona road dust; nanoclays; and lithium titanate. Both the total and respirable dustiness spanned two orders of magnitude (0.3-37.9% and 0.1-31.8% of the predispersed test powders, respectively). For many powders, a significant respirable dustiness was observed. For most powders studied, the respirable dustiness accounted for approximately one-third of the total dustiness. It is believed that this relationship holds for many fine and nanoscale test powders (i.e. those primarily selected for this study), but may not hold for coarse powders. Neither total nor respirable dustiness was found to be correlated with BET surface area, therefore dustiness is not determined by primary particle size. For a subset of test powders, aerodynamic particle size distributions by number were measured (with an electrical low-pressure impactor and an aerodynamic particle sizer). Particle size modes ranged from approximately 300 nm to several micrometers, but no modes below 100 nm, were observed. It is therefore unlikely that these materials would exhibit a substantial sub-100 nm particle contribution in a workplace. PMID:23065675

  12. Multiple feed powder splitter

    DOEpatents

    Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

    2002-01-01

    A device for providing uniform powder flow to the nozzles when creating solid structures using a solid fabrication system such as the directed light fabrication (DLF) process. In the DLF process, gas entrained powders are passed through the focal point of a moving high-power laser light which fuses the particles in the powder to a surface being built up in layers. The invention is a device providing uniform flow of gas entrained powders to the nozzles of the DLF system. The device comprises a series of modular splitters which are slidably interconnected and contain an integral flow control mechanism. The device can take the gas entrained powder from between one to four hoppers and split the flow into eight tubular lines which feed the powder delivery nozzles of the DLF system.

  13. Multiple feed powder splitter

    DOEpatents

    Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

    2001-01-01

    A device for providing uniform powder flow to the nozzles when creating solid structures using a solid fabrication system such as the directed light fabrication (DLF) process. In the DLF process, gas entrained powders are passed through the focal point of a moving high-power laser light which fuses the particles in the powder to a surface being built up in layers. The invention is a device providing uniform flow of gas entrained powders to the nozzles of the DLF system. The device comprises a series of modular splitters which are slidably interconnected and contain an integral flow control mechanism. The device can take the gas entrained powder from between one to four hoppers and split the flow into eight tubular lines which feed the powder delivery nozzles of the DLF system.

  14. Powder metallurgy in 1995

    SciTech Connect

    White, D.G. [Metal Powder Industries Federation, Princeton, NJ (United States)

    1995-08-01

    The powder metallurgy industry has enjoyed extraordinary growth during the last three years, based on progress in materials, processes, and equipment. Total metal powder shipments increased 18% in 1994 to 426,050 tons. For the first time, North American iron powder shipments went beyond 338,000 tons in 1994, a 17.4% increase over 1993. The copper and copper-base powder markets in 1994 reached 23,000 tons, growing slightly less than 3% over 1993. The parts segment of this market reached 19,670 tons, almost flat with 1993 because of the sharply rising price of copper on world commodity markets. This article will discuss advances in steel powders and processing, the range of iron powder applications, advanced particulate materials, equipment improvements, and standards development.

  15. Gas-Phase Production of Titanium Nitride and Carbide Powders

    NASA Astrophysics Data System (ADS)

    Harbuck, Donna D.; Davidson, Charles F.; Shirts, Monte B.

    1986-09-01

    The Bureau of Mines investigated a procedure to produce fine-sized titanium nitride, carbide, and carbonitride powders. These powders, because of their high hardness and abrasion resistance, can be substituted for tungsten carbide in some cutting tool applications. Titanium nitride and carbide powders can be cemented together with nickel. The investigated approach produces titanium nitride by reducing titanium tetrachloride with magnesium or sodium vapor in a nitrogen atmosphere at temperatures between 750 and 1,050°C (1,382 and 1,922°F). Titanium carbide and titanium carbonitride can be formed by adding methane to the nitrogen atmosphere. Titanium tetrachloride reduction efficiencies as high as 98% are achieved. X-ray diffraction analyses showed that the powders contain no major impurities. Because the reactions occur in the gas phase, powders finer than 1 ?m are produced.

  16. Magnetic fingerprint powder from a mineral indigenous to Thailand.

    PubMed

    Thonglon, Thatsanee; Chaikum, Nopadol

    2010-09-01

    A study was conducted to investigate whether natural magnetite (Fe3O4), which is an abundant mineral in Thailand, could be used as a magnetic powder in the detection of latent fingerprints. Because of the presence of impurities, powdered magnetite is only weakly attracted by a magnet and cannot be used as a magnetic fingerprint powder by itself. Mixing a small amount of magnetite powder with nickel powder greatly enhances the magnetic attraction. A mixture of magnetite powder and nickel powder in a mass ratio of approximately 1:100 was found to be suitable for use as a magnetic fingerprint powder. Fingerprints developed using the magnetite/nickel mixture on nonporous surfaces were found to exhibit good adherence and clarity. Using an automated fingerprint identification system, the number of minutiae detected in fingerprints developed by using the prepared powder on nonporous surfaces was found to be comparable to those detected in fingerprints developed by using a commercial black magnetic powder. The cost is lowered by more than 60%. PMID:20487149

  17. Structural and magnetic characterisation of CoSb{sub 2}O{sub 4}, and the substitution of Pb{sup 2+} for Sb{sup 3+}

    SciTech Connect

    Laune, Benjamin P. de [School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom); Greaves, Colin, E-mail: c.greaves@bham.ac.uk [School of Chemistry, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2012-03-15

    The nuclear and magnetic structures of the synthetic schafarzikite related material CoSb{sub 2}O{sub 4} have been determined from neutron powder diffraction data. The compound is tetragonal (P4{sub 2}/mbc) with refined lattice constants at 300 K of, a=8.49340(9) A, c=5.92387(8) A. The magnetic ordering is shown to be consistent with a C mode with moments aligned along [0 0 1]. Magnetic susceptibility measurements indicate a canted antiferromagnetic ground state, for which the ferromagnetic component shows unusually high coercivity. The thermal stability of CoSb{sub 2}O{sub 4} in air is reported. The substitution of Pb{sup 2+} for Sb{sup 3+} has been investigated and found to cause oxidation of both Co{sup 2+} to Co{sup 3+} and Sb{sup 3+} to Sb{sup 5+}. - Graphical Abstract: Structural changes on substitution of Pb{sup 2+} ions for Sb{sup 3+} ions in CoSb{sub 2}O{sub 4}. Highlights: Black-Right-Pointing-Pointer The structural details of CoSb{sub 2}O{sub 4} are reported for the first time. Black-Right-Pointing-Pointer The magnetic structure of CoSb{sub 2}O{sub 4} are reported for the first time. Black-Right-Pointing-Pointer The ordered magnetic structure has a canted antiferromagnetic arrangement. Black-Right-Pointing-Pointer The ferromagnetic component of the ordered arrangement has high coercivity. Black-Right-Pointing-Pointer Pb{sup 2+} can substitute for Sb{sup 3+} and oxidation of both Co{sup 2+} and Sb{sup 3+} occurs.

  18. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-05

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  19. Morphology and composition of Ni-Co electrodeposited powders

    SciTech Connect

    Maksimovic, V.M., E-mail: vesnam@vinca.rs [Institute of Nuclear Sciences, 'Vinca', University of Belgrade, 11001 Belgrade, P. O. Box 522 (Serbia); Lacnjevac, U.C. [Institute for Multidisciplinary research, University of Belgrade, P.O. Box 33, 11030 Belgrade (Serbia); Stoiljkovic, M.M. [Institute of Nuclear Sciences, 'Vinca', University of Belgrade, 11001 Belgrade, P. O. Box 522 (Serbia); Pavlovic, M.G. [Institute of Electrochemistry, ICTM, University of Belgrade, 11000 Belgrade, Njegoseva 12 (Serbia); Jovic, V.D. [Institute for Multidisciplinary research, University of Belgrade, P.O. Box 33, 11030 Belgrade (Serbia)

    2011-12-15

    The morphology, phase and chemical composition of Ni-Co alloy powders electrodeposited from an ammonium sulfate-boric acid containing electrolyte with different ratio of Ni/Co ions were investigated. The ratios of Ni/Co ions were 1/1, 1/2 and 1/3. The morphology, chemical composition and phase composition of the electrodeposited alloy powders were investigated using AES, SEM, EDS and XRD analysis. Composition of the electrolyte, i.e. the ratio of Ni/Co concentrations was found to influence both, the alloy phase composition and the morphology of Ni-Co alloy powders. At the highest ratio of Ni/Co = 1/1 concentrations typical 2D fern-like dendritic particles were obtained. With a decrease of Ni/Co ions ratio among 2D fern-like dendrites, 3D dendrites and different agglomerates were obtained. X-ray diffraction studies showed that the alloy powders mainly consisted of the face-centered cubic {alpha}-nickel phase and hexagonal close-packed {epsilon}-cobalt phase and minor proportions of face-centered cubic {alpha}-cobalt phase. The occurrence of the latter phase was observed only in the alloy powder with the higher cobalt concentration in electrolyte. The electrodeposition of Ni-Co powders occurred in an anomalous manner. - Highlights: Black-Right-Pointing-Pointer Ni-Co alloys powders were successfully electrodeposited. Black-Right-Pointing-Pointer Composition of the electrolyte (Ni/Co ions ratio) was found to influence on morphology of powders. Black-Right-Pointing-Pointer The electrodeposition of Ni-Co powders occurred in an anomalous manner.

  20. Photocatalytic and Antibacterial Activity of Titanium, Fluorine and Silver Co-Substituted Hydroxyapatite

    NASA Astrophysics Data System (ADS)

    Sandhyarani, M.; Rameshbabu, N.; Venkateswarlu, K.; Ravisankar, K. V.; Ashok, M.; Anandan, S.

    Synthetic hydroxyapatite (HA), an analogue of the mineral component of bone tissue has been widely used in medicine as bone replacing material. To impart specific properties, HA can be chemically modified by anionic and cationic substitutions during synthesis. Thus the present study was focused in synthesizing nanocrystalline Ti, Ag and F co-substituted HA by microwave synthesis. The prepared powders were characterized by XRD and FTIR for their crystal size, cystallinity and functional groups respectively. XRD spectra reveal that crystal size of prepared powders was in the range of 21-25 nm in as synthesized condition and 45-51 nm in 900 ?C heat-treated condition. Complete decomposition of HA to tri calcium phosphate was observed for Ti substituted HA powder after heat-treatment. Addition of F improved the thermal stability of Ti substituted HA as indicated by predominant phase of HA after heat-treatment. The photocatalytic activity of co-substituted HA powders was examined by degradation of methylene blue (5 × 10-5 M concentration) under visible light irradiation and the results were compared with pure HA. The degradation efficiency of co-substituted HA with respect to methylene blue was twice as high as that of pure HA. Ti and Ag has improved the visible light photocatalytic activity of HA, further F co-substitution has not affected the photocatalytic activity of substituted HA. The antibacterial effect of prepared powders was observed against 1 × 105 cells/mL of Escherichia coli using spread plate method at 24 h incubation period. Ag co-substituted HA showed complete inhibition of growth of Escherichia coli. Thus, among Ti, Ti-F, Ti-F-Ag substituted HA powders, Ti-F-Ag co-substituted HA with excellent visible light photocatalytic activity and anti-bacterial property is expected to be a potential candidate for biomedical applications.

  1. An examination of the H/D isotope substitution effect on selectivity and activity in the cavitating ultrasound hydrogenation of aqueous 3-buten-2-ol and 1,4-pentadien-3-ol on Pd-black

    SciTech Connect

    Boyles, Kelly R.; Chajkowski, Sarah M.; Disselkamp, Robert S.; Peden, Charles HF

    2006-05-24

    An H/D isotope effect study of the (H2 versus D2) hydrogenation of the aqueous substrates 3-buten-2-ol (3B2OL) and 1,4-pentadien-3-ol (14PD3OL) was performed using Pd-black catalyst. Either H2O or D2O solvents were employed (for alcohol H/D isotope substitution). Two experimental processing conditions of cavitating ultrasound (CUS) and stirred/silent (SS) methods were used. Products formed include 2-butanol and 2-butanone for the former, and 3-pentanol and 3-pentanone for the latter. The observed selectivity and pseudo-first order reaction rate coefficients (e.g., activity) to these products enabled a mechanistic interpretation of the various reaction conditions to be proposed. Experiments utilized a 50 mL batch reactor maintained at 298 K, employed 5.4 atm of H2 or D2 gas, while seven aliquots were collected during the course of the reaction. We have utilized 1-propanol as an inert dopant in all experiments to enable the rapid onset of cavitation in the CUS systems as described earlier [R.S. Disselkamp et al., J. Catal., 227, 552 (2004)]. The following conclusions were noted. First, the activity of the CUS compared to SS processing were ~100-fold larger. Second, variable catalyst loading experiments for stirred/silent D2 hydrogenation processing indicated that mass transfer of hydrogen gas to the Pd-surface played a role such that higher catalyst loading reduced surface D-atom concentrations and reduced saturated alcohol formation (e.g., via reduced H-addition to surface alkyl radicals). Third, for CUS processing the ketone selectivities for experiments employing water compared to D2O indicated that 3B2OL were twice as large, whereas for 14PD3OL they were comparable. This suggests, somewhat surprisingly, that for 3B2OL enol tautomerization to ketone is a slow, and possibly rate-controlling, process. Finally, again for CUS processing, the similarity in ketone selectivities (all ~17%) for H2 compared to D2 hydrogenation for both 3B2OL and 14PD3OL suggest that both H/D isotopes have rapid surface diffusion and hence give rise to nearly equal selectivies. Restated, the thermal or cavitating ultrasound activation is much greater than the surface H/D diffusion barrier.

  2. Sintering titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-09-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press-and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics, with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  3. Compaction of Titanium Powders

    SciTech Connect

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  4. Ceramic powder compaction

    SciTech Connect

    Glass, S.J.; Ewsuk, K.G. [Sandia National Labs., Albuquerque, NM (United States); Mahoney, F.M. [Norton Co., Worcester, MA (United States)

    1995-12-31

    With the objective of developing a predictive model for ceramic powder compaction we have investigated methods for characterizing density gradients in ceramic powder compacts, reviewed and compared existing compaction models, conducted compaction experiments on a spray dried alumina powder, and conducted mechanical tests and compaction experiments on model granular materials. Die filling and particle packing, and the behavior of individual granules play an important role in determining compaction behavior and should be incorporated into realistic compaction models. These results support the use of discrete element modeling techniques and statistical mechanics principals to develop a comprehensive model for compaction, something that should be achievable with computers with parallel processing capabilities.

  5. The Black Body Function.

    ERIC Educational Resources Information Center

    Lawson, D. A.

    1998-01-01

    Discusses using black body function for radiative heat transfer, which can be used in a real-life application in a number of different topics in A-level and first-year undergraduate mathematical methods courses such as differentiation, solving nonlinear equations, and integration by substitution. (ASK)

  6. POWDER COAT APPLICATIONS

    EPA Science Inventory

    The report discusses an investigation of critical factors that affect the use of powder coatings on the environment, cost, quality, and production. The investigation involved a small business representative working with the National Defense Center for Environmental Excellence (ND...

  7. Pyrotechnic filled molding powder

    DOEpatents

    Hartzel, Lawrence W. (Dayton, OH); Kettling, George E. (Cincinnati, OH)

    1978-01-01

    The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

  8. Mystery Powder Investigation

    NSDL National Science Digital Library

    Rachel HallettNjuguna

    2012-07-27

    Students will use their skills as scientists to identify a mystery white powder. This lesson is a hands-on, engaging way to build students' understanding of physical and chemical properties of several common compounds.

  9. [Otologic diagnosis: powder technique].

    PubMed

    Tolsdorff, P

    2011-06-01

    The otologic diagnostic powder test with grape - sugar simple will be performed with a powder - blower. It permits a good differentiation between dry squamous epithelium and wet mucosa. In our opinion this test therefore is unrenouncable in microscopic differentiation between mucosa in central perforations on one hand and atrophic scars, retraction pockets or adhesive epithelium of the drum or complete atelectasis of the tympanic cavity on the other hand. PMID:21626473

  10. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction...

  11. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction...

  12. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction...

  13. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction product...substituted triazine amino substituted benezenesulfonic acid reaction...

  14. Synthesis and characterization of hydroxyapatite, fluoride-substituted hydroxyapatite and fluorapatite

    Microsoft Academic Search

    M. Wei; J. H. Evans; T. Bostrom; L. Grøndahl

    2003-01-01

    Powders of hydroxyapatite (HA), partially fluoride-substituted hydroxyapatite (fHA), and fluorapatite (FA) were synthesized in house using optimum methods to achieve relatively pure powders. These powders were assessed by the commonly used bulk techniques of X-ray diffraction (XRD), Fourier transform infra-red (FTIR) and FT-Raman spectroscopies, inductively coupled plasma atomic emission spectroscopy (ICP-AES), and F-selective electrode. In addition, the current study has

  15. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-28

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  16. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-19

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  17. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  18. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goval, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-06-07

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  19. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-14

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  20. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-01-25

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  1. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-05-10

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  2. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  3. Black Eye

    MedlinePLUS

    ... Eye Health News Consumer Alerts What Is a Black Eye? Tweet Black eye is a phrase used to describe bruising ... dark bruising in the tissue. What Is a Black Eye? Black Eye Symptoms What Causes a Black ...

  4. Stable powders made from photosensitive polycrystalline complexes of heterocyclic monomers and their polymers

    NASA Technical Reports Server (NTRS)

    Hodko, Dalibor (Inventor); Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

    1999-01-01

    The present invention relates to a low electronic conductivity polymer composition having well dispersed metal granules, a stable powder made from photosensitive polycrystalline complexes of pyrrole, or its substituted derivatives and silver cations for making the polymer composition, and methods of forming the stable powder and polymer composition, respectively. A polycrystalline complex of silver and a monomer, such as pyrrole, its substituted derivatives or combinations thereof, is precipitated in the form of a stable photosensitive powder upon addition of the monomer to a solvent solution, such as toluene containing an electron acceptor. The photosensitive powder can be stored in the dark until needed. The powder may be dissolved in a solvent, cast onto a substrate and photopolymerized.

  5. A study of La-substituted strontium hexaferrite by hydrothermal synthesis

    Microsoft Academic Search

    J. F Wang; C. B Ponton; R Grössinger; I. R Harris

    2004-01-01

    The possibility of replacing Sr by La and Fe by Co and the subsequent improvement of the magnetic properties of the M-type ferrite stimulated our interest in studying other rare-earth ion substitutions. We have found that Sm and Nd substitutions can increase the coercivity of the hydrothermally synthesised Sr hexaferrite powder without causing any significant fall in the saturation magnetisation.

  6. A study of Pr-substituted strontium hexaferrite by hydrothermal synthesis

    Microsoft Academic Search

    J. F. Wang; C. B. Ponton; I. R. Harris

    2005-01-01

    The possibility of replacing Sr by La and Fe by Co and the subsequent improvement of the magnetic properties of the M-type ferrite stimulated our interest in studying other rare-earth ion substitutions. We have found that Sm and Nd substitutions can increase the coercivity of the hydrothermally synthesised Sr hexaferrite powder without causing any significant fall in the saturation magnetisation.

  7. Synthesis of high surface area ZnO powder by continuous precipitation

    SciTech Connect

    Boz, Ismail, E-mail: ismailb@istanbul.edu.tr [Istanbul University, Faculty of Engineering, Department of Chemical Engineering, Avcilar, Istanbul 34320 (Turkey)] [Istanbul University, Faculty of Engineering, Department of Chemical Engineering, Avcilar, Istanbul 34320 (Turkey); Kaluza, Stefan [Laboratory of Industrial Chemistry, Ruhr-University Bochum, Universitaetsstr. 150, Bochum 44780 (Germany)] [Laboratory of Industrial Chemistry, Ruhr-University Bochum, Universitaetsstr. 150, Bochum 44780 (Germany); Boroglu, Mehtap Safak [Istanbul University, Faculty of Engineering, Department of Chemical Engineering, Avcilar, Istanbul 34320 (Turkey)] [Istanbul University, Faculty of Engineering, Department of Chemical Engineering, Avcilar, Istanbul 34320 (Turkey); Muhler, Martin [Laboratory of Industrial Chemistry, Ruhr-University Bochum, Universitaetsstr. 150, Bochum 44780 (Germany)] [Laboratory of Industrial Chemistry, Ruhr-University Bochum, Universitaetsstr. 150, Bochum 44780 (Germany)

    2012-05-15

    Graphical abstract: High surface area ZnO powders are synthesized by a low temperature continuous precipitation under ultrasonication. Urea is used as precipitating agent so that no contamination of ZnO powder emanating from precipitating agent, such as, alkalis, is observed. pH and type of precursor greatly affects the surface area and other properties. In this manuscript, we report a very simple and effective continuous precipitation to synthesize high surface area ZnO powder. Highlights: Black-Right-Pointing-Pointer The synthesis of high surface area ZnO powder was achieved at 90 Degree-Sign C in a continuous precipitation unit. Black-Right-Pointing-Pointer Continuous precipitation unit was ultrasonicated to improve final product homogeneity. Black-Right-Pointing-Pointer Precipitation intermediate, hydrozincite, was led to high surface area ZnO powder. Black-Right-Pointing-Pointer The synthesized ZnO nanoparticles had a rather uniform mesoporous structure. -- Abstract: Synthesis of high surface area ZnO powder was achieved by continuous precipitation using zinc ions and urea at low temperature of 90 Degree-Sign C. The powder precipitated resulted in high-purity single-phase ZnO powder when calcined at 280 Degree-Sign C for 3 h in air. The solution pH and the precipitation duration strongly affected the surface area of the calcined ZnO powder. Detailed structural characterizations demonstrated that the synthesized ZnO powder were single crystalline with wurtzite hexagonal phase. The powdered samples precipitated by homogeneous precipitation crystallized directly to hydrozincite without any intermediate phase formation. The phase structures, morphologies and properties of the final ZnO powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering particle size analysis (DLS), and nitrogen physisorption in order to determine the specific surface area (BET) and the pore size distribution (BJH).

  8. Co-substitution at the Mn-site in YMnO{sub 3}: Structural stability and physical properties

    SciTech Connect

    Malo, S., E-mail: sylvie.malo@ensicaen.fr [CNRS - UMR 6508-CRISMAT, 14050 Caen (France); ENSICAEN - UMR 6508-CRISMAT, 14050 Caen (France); Universite de Caen Basse-Normandie - UMR 6508-CRISMAT, 14050 Caen (France); Maignan, A. [CNRS - UMR 6508-CRISMAT, 14050 Caen (France) [CNRS - UMR 6508-CRISMAT, 14050 Caen (France); ENSICAEN - UMR 6508-CRISMAT, 14050 Caen (France); Universite de Caen Basse-Normandie - UMR 6508-CRISMAT, 14050 Caen (France)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Solid state synthesis of several series of hexagonal co-substituted YMn{sub 1-x}(M Prime ,M Double-Prime ){sub x}O{sub 3}. Black-Right-Pointing-Pointer Evidencing the critical parameters which govern the stabilization of the hexagonal phase. Black-Right-Pointing-Pointer Inducing a decrease of the antiferromagnetic ordering temperature by co-substitutions. -- Abstract: The YMnO{sub 3} oxide, crystallizing in the P6{sub 3}cm space group is one of the most studied multiferroic material. While these properties can be modified by substitutions at the Mn-site, the peculiar fivefold coordination appears to limit the M solubility range in YMn{sub 1-x}M{sub x}O{sub 3}. This motivated the preparation by solid state reaction of several series of co-substituted YMn{sub 1-x}(M Prime ,M Double-Prime ){sub x}O{sub 3}, which were studied using both powder X-ray diffraction and transmission electron microscopy. The cation pairs have been chosen for their ability to adopt a fivefold coordination similar to that of Mn{sup 3+} in YMnO{sub 3}, to keep a constant average trivalent oxidation state and to maintain an average cationic radius similar to that of Mn{sup 3+}. For YMn{sub 1-x}(Cu{sub 1/2}Ti{sub 1/2}){sub x}O{sub 3}, a complete solid solution is observed without cation ordering. For all other studied cation pairs, the solubility range is always reaching a minimum value of 25% for the Zn containing pairs (Zn{sub 2/3}V{sub 1/3} and Zn{sub 3/4}Mo{sub 1/4}), a maximum of 50% being reached for the Cu containing pairs (Cu{sub 2/3}V{sub 1/3}, Cu{sub 2/3}Nb{sub 1/3} and Cu{sub 3/4}W{sub 1/4}). Interestingly, the non-centrosymmetric P6{sub 3}cm space group is retained within the solubility range without generating cation ordering phenomena. These co-substitutions at the Mn{sup 3+} are found to induce a decrease of the antiferromagnetic ordering temperature, the T{sub N} variations being similar to the temperature decrease of the dielectric anomaly. Thus, these oxides are interesting candidates for the study of the multiferroic behavior of YMnO{sub 3} derivatives.

  9. Ultrafine hydrogen storage powders

    DOEpatents

    Anderson, Iver E. (Ames, IA); Ellis, Timothy W. (Doylestown, PA); Pecharsky, Vitalij K. (Ames, IA); Ting, Jason (Ames, IA); Terpstra, Robert (Ames, IA); Bowman, Robert C. (La Mesa, CA); Witham, Charles K. (Pasadena, CA); Fultz, Brent T. (Pasadena, CA); Bugga, Ratnakumar V. (Arcadia, CA)

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  10. Fabricating solid carbon porous electrodes from powders

    DOEpatents

    Kaschmitter, J.L.; Tran, T.D.; Feikert, J.H.; Mayer, S.T.

    1997-06-10

    Fabrication is described for conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive deionization, and waste treatment. Electrodes fabricated from low surface area (<50 m{sup 2}/gm) graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon composites with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to high surface area carbons, fuel cell electrodes can be produced. 1 fig.

  11. Fabricating solid carbon porous electrodes from powders

    DOEpatents

    Kaschmitter, James L. (Pleasanton, CA); Tran, Tri D. (Livermore, CA); Feikert, John H. (Livermore, CA); Mayer, Steven T. (San Leandro, CA)

    1997-01-01

    Fabrication of conductive solid porous carbon electrodes for use in batteries, double layer capacitors, fuel cells, capacitive dionization, and waste treatment. Electrodes fabricated from low surface area (<50 m.sup.2 /gm) graphite and cokes exhibit excellent reversible lithium intercalation characteristics, making them ideal for use as anodes in high voltage lithium insertion (lithium-ion) batteries. Electrodes having a higher surface area, fabricated from powdered carbon blacks, such as carbon aerogel powder, carbon aerogel microspheres, activated carbons, etc. yield high conductivity carbon compositives with excellent double layer capacity, and can be used in double layer capacitors, or for capacitive deionization and/or waste treatment of liquid streams. By adding metallic catalysts to be high surface area carbons, fuel cell electrodes can be produced.

  12. Iowa Powder Atomization Technologies

    SciTech Connect

    None

    2012-01-01

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  13. Investigation of Soap Powders

    E-print Network

    Bragg, G.A.

    1913-01-01

    pound , Price 5 cents. Analysis• Moisture 13.36$ Soap 38.96$ NaaCOa 45.44$ Total 97.76$ C Q H C L U S I O B . To facilitate comparison, the following table has been compiled, showing at a glance the relative compositions of the powders... Price 5 cents. Analysis. Moisture 13.69$ Soap 30.86$ N« aC0 3 .. 55.41$ Total 99.96$ Wizard Washing Powder. Manufactured by Floor Clean Company, Chicago. Wt. 1 pound Price 5 cents. Analysis. Moisture 16.54$ Soap 13.24$ Na 2C0 3 68.38$ Total...

  14. Iowa Powder Atomization Technologies

    ScienceCinema

    None

    2013-03-01

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  15. Fluoridation of hydroxyapatite powder by ammonium hexafluorosilicate.

    PubMed

    Murata, H; Ishikawa, K; Tenshin, S; Horiuchi, S; Nakanishi, M; Asaoka, K; Kawata, T; Yamamoto, T T

    1996-01-01

    Diamine silver fluoride [AgF: (NH3)2AgF] is a unique fluoride solution used clinically in Japan for primary teeth. AgF has been shown to reduce dental caries and dentine hypersensitivity. However, AgF also stains teeth black due to sulfide precipitation and thus is unacceptable for permanent teeth. In the present study, the potential value of ammonium hexafluorosilicate [SiF: (NH4)2SiF6], which has a formula similar to that of AgF but contains no Ag, was studied with respect to its ability to fluoridate apatite. Hydroxyapatite [HAP: Ca10(PO4)6(OH)2] powder was treated with several topical fluoride solutions, i.e. neutral sodium fluoride, acidulated phosphate fluoride (APF) along with AgF and SiF. Following treatment, the HAP powders were analyzed for their fluorine content, crystallinity changes, and solubility in acidic solution. The highest level of fluoridated HAP [FAP: Ca10(PO4)6(OH)xF2-x] was observed in HAP powder treated with SiF, even though more total fluorine in the form of FAP and CaF2 was observed in HAP powder samples treated with APF. Presumably as a consequence of this higher level of FAP formation after SiF treatment, the highest level of crystallinity along with the lowest solubility in acidic solution were observed in HAP powder treated with SiF solution. We concluded, therefore, that SiF may have potential value for use as a topical fluoride solution. PMID:8946095

  16. Partial substitution of Mo{sup 6+} by S{sup 6+} in the fast oxide ion conductor La{sub 2}Mo{sub 2}O{sub 9}: Synthesis, structure and sulfur depletion

    SciTech Connect

    Mhadhbi, Noureddine [LUNAM Universite, Universite du Maine, CNRS UMR 6283, Institut des Molecules et des Materiaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Corbel, Gwenaeel, E-mail: gwenael.corbel@univ-lemans.fr [LUNAM Universite, Universite du Maine, CNRS UMR 6283, Institut des Molecules et des Materiaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France); Lacorre, Philippe; Bulou, Alain [LUNAM Universite, Universite du Maine, CNRS UMR 6283, Institut des Molecules et des Materiaux du Mans, Avenue Olivier Messiaen, 72085 Le Mans Cedex 9 (France)

    2012-06-15

    Powder-solid state reaction route using La{sub 2}(SO{sub 4}){sub 3} as sulfur source was used to prepare compositions of the solid solution La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9}. Single phases were only obtained in the substitution range extending up to y=0.8 (40 mol% S) at the annealing temperature of 850 Degree-Sign C with regard to the limit of stability of the lanthanum sulphate reactant. Within the synthesis conditions, a stabilization of the high temperature {beta}-form is observed from and above y=0.1 (5 mol% S). Temperature-controlled X-ray diffraction and thermogravimetric analyses have shown that La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders undergo thermal decompositions in two steps. Heating above 900 Degree-Sign C, a sulfur depletion to the benefit of molybdenum in La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders leads to the formation of La{sub 2}SO{sub 6}. At higher temperature, the exsolved La{sub 2}SO{sub 6} phase then decomposes into La{sub 2}O{sub 3}, which in turn reacts with the sulfur-depleted La{sub 2}Mo{sub 2}O{sub 9} phase to form La{sub 2}MoO{sub 6}. The present study also reveals that depending on the substitution rate y, the sulfur depletion can be induced by ball-milling of raw powders. Along the La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} series, the isovalent substitution of molybdenum by sulfur tends to restrict in magnitude, or even to suppress above 400 Degree-Sign C, the distortive thermal expansion of the cubic {beta}-type structure, thus strongly decreasing the conductance at high temperature. - Graphical abstract: La{sub 2}O{sub 3}-MoO{sub 3}-'SO{sub 3}' ternary phase diagram showing the exsolution path at low temperature (white arrows) and the total decomposition path at high temperature (black arrows) of {beta}-La{sub 2}Mo{sub 2-y}S{sub y}O{sub 9} raw powders. Highlights: Black-Right-Pointing-Pointer Isovalent substitution of molybdenum by sulfur in La{sub 2}Mo{sub 2}O{sub 9} up to 40 mol%. Black-Right-Pointing-Pointer Stabilization of the {beta}-form for a sulfur content greater than or equal to 5 mol%. Black-Right-Pointing-Pointer Decomposition by sulfur exsolution induced by thermal treatment or ball-milling. Black-Right-Pointing-Pointer Reduction or even cancellation of the distortive thermal expansion above 400 Degree-Sign C. Black-Right-Pointing-Pointer Decrease of conductance at high T involved by the low thermal expansion above 400 Degree-Sign C.

  17. Demystifying Mystery Powders.

    ERIC Educational Resources Information Center

    Kotar, Michael

    1989-01-01

    Describes science activities which use simple chemical tests to distinguish between materials and to determine some of their properties. Explains the water, iodine, heat, acid, baking soda, acid/base indicator, glucose, and sugar tests. Includes activities to enhance chemical testing and a list of suggested powders for use. (RT)

  18. Electrically conductive ceramic powders

    NASA Astrophysics Data System (ADS)

    Lu, Yanxia

    1999-11-01

    Electrically conductive ceramic powders were investigated in this project. There are three ways to produce those materials. The first is doping alkali metal into the titanium dioxides in an inert or reducing atmosphere. The second is reducing un-doped titanium dioxide, forming a non-stoichiometric composition in a hydrogen atmosphere. The third is to coat a conductive layer, reduced titanium dioxide, on an insulating core such as alumina. Highly conductive powders have been produced by all these processes. The conductivity of powder compacts ranged between 10-2 and 10° S/cm. A novel doping process was developed. All samples were doped by a solid-vapor reaction instead of a solid state reaction. Titanium dioxide was doped with alkali metals such as Na or Li in this study. The alkali metal atom contributes an electron to the host material (TiO2), which then creates Ti 3+ ion. The conductivity was enhanced by creating the donor level due to the presence of these Ti3+ ions. The conductivity of those alkali doped titanium oxides was dependent on the doping level and charge mobility. Non-stoichiometric titanium oxides were produced by reduction of titanium dioxide in a hydrogen atmosphere at 800°C to 1000°C for 2 to 6 hours. The reduced titanium oxides showed better stability with respect to conductivity at ambient condition when compared with the Na or Li doped samples. Conductive coatings were prepared by coating titanium precursors on insulating core materials like SiO2, Al2O3 or mica. The titania coating was made by hydrolysis of titanyl sulfate (TiOSO 4) followed by a reduction procedure to form reduced titanium oxide. The reduced titanium oxides are highly conductive. A uniform coating of titanium oxides on alumina cores was successfully produced. The conductivity of coated powder composites was a function of coating quantity and hydrolysis reaction temperature. The conductivity of the powder as a function of structure, composition, temperature, frequency and moisture was studied. Three classifications of structure were identified for alkali-doped titanium oxides: (1) Pure titanium dioxide phase with alkali ions located in interstitial positions. (2) The titanium bronze phases. (3) Alkali-doped titanium oxides. Highly conductive powders were obtained in the first and second classifications with conductivity of 10-2 to 10° S/cm. Materials in the third classification had poor conductivity below 10-3 S/cm. The conductivity of a powder was determined mainly by the grain conductivity and the grain contact conductivity. The present results of impedance spectroscopy suggested that the grain contact resistance was a major factor of the electrical resistance of the samples. The aging effect at different moisture conditions was also caused by an increase of the contact resistance. Both sodium-doped and reduced titanium oxides showed re-oxidation at elevated temperature (above 140°C) in air, which is most probably caused by oxidizing the Ti3+ ions under those conditions. Lithium doped titanium oxides did not show this re-oxidation at temperatures up to 200°C. Theoretical models were applied to describe the effects of porosity, contact configuration and grain surface on conductivity of powder compacts. Percolation theory was used in the present study to demonstrate the effect of mixtures of conductive and non-conductive powders, which is one of applications for conductive ceramic powders when they are used as filler materials in paper, paints or plastics.

  19. Si-substituted hydroxyapatite nanopowders: Synthesis, thermal stability and sinterability

    SciTech Connect

    Bianco, Alessandra [University of Rome Tor Vergata, Department of Chemical Sciences and Technologies, INSTM Research Unit Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy)], E-mail: bianco@stc.uniroma2.it; Cacciotti, Ilaria [University of Rome Tor Vergata, Department of Chemical Sciences and Technologies, INSTM Research Unit Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy); Lombardi, Mariangela [Politecnico of Torino, Department of Materials Science and Chemical Engineering, INSTM Research Unit Politecnico di Torino: LINCE Lab, Corso Duca degli Abruzzi, 24-10129 Torino (Italy)], E-mail: mariangela.lombardi@polito.it; Montanaro, Laura [Politecnico of Torino, Department of Materials Science and Chemical Engineering, INSTM Research Unit Politecnico di Torino: LINCE Lab, Corso Duca degli Abruzzi, 24-10129 Torino (Italy)

    2009-02-04

    Synthetic hydroxyapatites incorporating small amounts of Si have shown improved biological performances in terms of enhanced bone apposition, bone in-growth and cell-mediated degradation. This paper reports a systematic investigation on Si-substituted hydroxyapatite (Si 1.40 wt%) nanopowders produced following two different conventional wet methodologies: (a) precipitation of Ca(NO{sub 3}){sub 2}.4H{sub 2}O and (b) titration of Ca(OH){sub 2}. The influence of the synthesis process on composition, thermal behaviour and sinterability of the resulting nanopowders is studied. Samples were characterised by electron microscopy, induced coupled plasma atomic emission spectroscopy, thermal analysis, infrared spectroscopy, N{sub 2} adsorption measurements, X-ray diffraction and dilatometry. Semicrystalline Si-substituted hydroxyapatite powders made up of needle-like nanoparticles were obtained, the specific surface area ranged between 84 and 110 m{sup 2}/g. Pure and Si-substituted hydroxyapatite nanopowders derived from Ca(NO{sub 3}){sub 2}.4H{sub 2}O decomposed around 1000 deg. C. Si-substituted hydroxyapatite nanopowders obtained from Ca(OH){sub 2} were thermally stable up to 1200 deg. C and showed a distinct decreased thermal stability with respect to the homologous pure sample. Si-substituted hydroxyapatites exhibited higher sintering temperature and increased total shrinkage with respect to pure powders. Nanostructured dense ceramics were obtained by sintering at 1100 deg. C Si-substituted hydroxyapatites derived from Ca(OH){sub 2}.

  20. Specific surface area and chemical reactivity of quartz powders during mechanical processing

    SciTech Connect

    Meloni, Paola [Dipartimento di Ingegneria Chimica e Materiali, Universita degli Studi di Cagliari, piazza d'Armi, I-09123 Cagliari (Italy) [Dipartimento di Ingegneria Chimica e Materiali, Universita degli Studi di Cagliari, piazza d'Armi, I-09123 Cagliari (Italy); Laboratorio per lo studio dei Materiali 'Colle di Bonaria', Universita degli Studi di Cagliari, via Ravenna, I-09100 Cagliari (Italy); Carcangiu, Gianfranco [Laboratorio per lo studio dei Materiali 'Colle di Bonaria', Universita degli Studi di Cagliari, via Ravenna, I-09100 Cagliari (Italy) [Laboratorio per lo studio dei Materiali 'Colle di Bonaria', Universita degli Studi di Cagliari, via Ravenna, I-09100 Cagliari (Italy); Istituto di Geologia Ambientale e Geoingegneria (IGAG), CNR, piazza d'Armi, I-09123 Cagliari (Italy); Delogu, Francesco, E-mail: delogu@dicm.unica.it [Dipartimento di Ingegneria Chimica e Materiali, Universita degli Studi di Cagliari, piazza d'Armi, I-09123 Cagliari (Italy)] [Dipartimento di Ingegneria Chimica e Materiali, Universita degli Studi di Cagliari, piazza d'Armi, I-09123 Cagliari (Italy)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Quartz powders were submitted to mechanical processing. Black-Right-Pointing-Pointer The specific surface area and the chemical reactivity increased. Black-Right-Pointing-Pointer A model was developed to describe the observed processes. Black-Right-Pointing-Pointer The amount of powder processed at impact was estimated. Black-Right-Pointing-Pointer The surface density of reactive centers was also estimated by using a test reaction. -- Abstract: The present work focuses on the specific surface area increase, and on the related chemical reactivity enhancement of quartz powders submitted to mechanical processing. The mechanical treatment was carried out in a suitably developed ball mill allowing the control of the frequency and energy of the impacts between ball and reactor. The specific surface area was directly measured by nitrogen physisorption, whereas electron microscopy was used to determine the size distribution of powder particles. Based on the experimental results, a simplified mathematical model was developed to describe the process of specific surface area increase on a phenomenological basis. The model permits to gain valuable information on the amount of powder processed in individual impacts. The density of reactive centers at the surface of powder particles was also estimated by using the neutralization of a free radical as a test reaction. It is shown that the surface density of reactive centers increases with the energy of collisions.

  1. Method to blend separator powders

    DOEpatents

    Guidotti, Ronald A. (Albuquerque, NM); Andazola, Arthur H. (Albuquerque, NM); Reinhardt, Frederick W. (Albuquerque, NM)

    2007-12-04

    A method for making a blended powder mixture, whereby two or more powders are mixed in a container with a liquid selected from nitrogen or short-chain alcohols, where at least one of the powders has an angle of repose greater than approximately 50 degrees. The method is useful in preparing blended powders of Li halides and MgO for use in the preparation of thermal battery separators.

  2. Method for synthesizing powder materials

    DOEpatents

    Buss, R.J.; Ho, P.

    1988-01-21

    A method for synthesizing ultrafine powder materials, for example, ceramic and metal powders, comprises admitting gaseous reactants from which the powder material is to be formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400/degree/K (127/degree/C). The gaseous reactants are directed through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material. 1 fig.

  3. Accuracy in Powder Diffraction IV

    E-print Network

    Magee, Joseph W.

    Accuracy in Powder Diffraction IV Program April 22-25, 2013 Photo credit ©2000 Robert Rathe #12;2 3 Accuracy in Powder Diffraction IV Program April 22-25, 2013 Day 1 | 22nd April Time Activity Chair 08 Introduction to program (Madsen, Cline) James Cline Ian Madsen 09:45 - 10:30 Accuracy in Powder Diffraction

  4. Modern developments in powder metallurgy

    SciTech Connect

    Aqua, E.N.; Whitman, C.I.

    1984-01-01

    This book presents the papers given at a conference on metal powders. Topics considered at the conference included sintering fundamentals, liquid phase and activated sintering, stainless steels, copper-base powder metallurgy, aluminium alloys, refractory metals, carbides, cutting tools, friction, wear, and powder production.

  5. Florida's Substitute Teachers.

    ERIC Educational Resources Information Center

    Odutola, Adeniji A.; Etemadi, Judy N.

    2002-01-01

    Describes the statutory duties of the Florida Education Standards Commission, highlighting a study of the working conditions of Florida's substitute teachers. Researchers collected data on school board policies regarding substitutes' educational levels required, initial training and staff development opportunities required, salary schedules, and…

  6. Effects of scandium substitution on the crystal structure and luminescence properties of LuBO{sub 3}: Ce{sup 3+}

    SciTech Connect

    Wu, Yuntao, E-mail: caswyt@hotmail.com [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 215 Chengbei Road, Jiading, Shanghai 201800 (China)] [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 215 Chengbei Road, Jiading, Shanghai 201800 (China); Ren, Guohao, E-mail: rgh@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 215 Chengbei Road, Jiading, Shanghai 201800 (China)] [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 215 Chengbei Road, Jiading, Shanghai 201800 (China); Ding, Dongzhou; Pan, Shangke [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 215 Chengbei Road, Jiading, Shanghai 201800 (China)] [Shanghai Institute of Ceramics, Chinese Academy of Sciences, No. 215 Chengbei Road, Jiading, Shanghai 201800 (China); Yang, Fan [California Institute of Technology, Pasadena, CA 91125 (United States)] [California Institute of Technology, Pasadena, CA 91125 (United States)

    2012-10-15

    The calcite phase of LuBO{sub 3} and ScBO{sub 3} polycrystalline powders were synthesized by solid state reaction method, and the Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce (x=0.2, 0.5, 0.7) single crystals were grown by the Czochralski method. A large composition deviation between the initial polycrystalline powders and final single crystal was confirmed by electron probe micro-analysis. Raman spectroscopy revealed that moderate lattice disorder was induced by scandium substitution. However, based on the single crystal X-ray study, we finally concluded that the crystal structure of lutetium scandium orthoborate still crystallized in the rhombohedral system belonging to R3{sup -}c. Furthermore, the relationship between the energies of the five 5d levels of Ce{sup 3+} and the crystalline environment was revealed. The total redshift, total crystal field splitting, and centroid shift of Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce{sup 3+} were calculated based on their VUV excitation spectra. The variations trend of these observed spectroscopic parameters was in accordance with the predicted ones. - Graphical abstract: The crystal structure of Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce is rhombohedral system with R3{sup -}c space group. The relationship between the energies of the five Ce{sup 3+} 5d levels and the crystalline environment is established. Highlights: Black-Right-Pointing-Pointer Moderate lattice disorder is induced by scandium doping. Black-Right-Pointing-Pointer The crystal structure of Lu{sub 1-x}Sc{sub x}BO{sub 3}:Ce is rhombohedral system with R3{sup -}c space group. Black-Right-Pointing-Pointer Relationship between energies of Ce{sup 3+} 5d levels and crystalline environment is established. Black-Right-Pointing-Pointer The spectroscopic parameters are experimentally and theoretically calculated.

  7. Sustainability and substitutability.

    PubMed

    Fenichel, Eli P; Zhao, Jinhua

    2015-02-01

    Developing a quantitative science of sustainability requires bridging mathematical concepts from fields contributing to sustainability science. The concept of substitutability is central to sustainability but is defined differently by different fields. Specifically, economics tends to define substitutability as a marginal concept while fields such as ecology tend to focus on limiting behaviors. We explain how to reconcile these different views. We develop a model where investments can be made in knowledge to increase the elasticity of substitution. We explore the set of sustainable and optimal trajectories for natural capital extraction and built and knowledge capital accumulation. Investments in substitutability through knowledge stock accumulation affect the value of natural capital. Results suggest that investing in the knowledge stock, which can enhance substitutability, is critical to desirable sustainable outcomes. This result is robust even when natural capital is not managed optimally. This leads us to conclude that investments in the knowledge stock are of first order importance for sustainability. PMID:24789570

  8. Processing polymeric powders

    NASA Technical Reports Server (NTRS)

    Throne, James L.

    1989-01-01

    The concept of uniformly and continuously depositing and sinter-fusing nominal 0.1 to 40 microns dimensioned electrostatically charged polymer powder particles onto essentially uniformly spread 5 to 20 micron grounded continuous fiber tow to produce a respoolable thermoplastic composite two-preg was formulated at NASA Langley. The process was reduced to practice under a NASA grant at the University of Akron this spring. The production of tow-preg is called phase 1. The production of ultrafine polymer powders from 5 to 10 percent (wt) polymer solids in solvent is considered. This is phase 0 and is discussed. The production of unitape from multi tow-pregs was also considered. This is phase 2 and is also discussed. And another approach to phase 1, also proposed last summer, was scoped. This is phase 1A and is also discussed.

  9. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath (Littleton, CO)

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  10. In situ synthesis of silicon-substituted biphasic calcium phosphate and their performance in vitro

    NASA Astrophysics Data System (ADS)

    Song, Chang-Weon; Kim, Tae-Wan; Kim, Dong-Hyun; Jin, Hyeong-Ho; Hwang, Kyu-Hong; Lee, Jong Kook; Park, Hong-Chae; Yoon, Seog-Young

    2012-01-01

    In situ preparation of silicon (Si) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/ ?-tricalcium phosphate (?-TCP) were carried out through aqueous co-precipitation method. The concentrations of added silicon were varied with the phosphor in order to obtain constant Ca/(P+Si) ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized silicon substituted BCP powders. The characterization revealed that the formation of biphasic mixtures of different HAp/ ?-TCP ratios was dependent on the content of silicon. After immersing in Hanks' balanced salt solution (HBSS) for 1 week, 3 wt% silicon substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. In the case of 1 wt% silicon substituted BCP powders, the degradation behavior was detected after immersion in HBSS for 3 weeks. On the other hand, silicon unsubtituted BCP powders were not degraded even after that duration. On the basis of these results, silicon substituted BCP is able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. This enhanced reactivity resulted in reduction for the stability of the ?-TCP structure due to SiO4 tetrahedral distortion and disorder at the hydroxyl site when silicon incorporates into BCP.

  11. [Esophageal substitute corrective operations].

    PubMed

    B?aszczuk, J; Grabowski, K; Wierzbicki, J; Adamus, A; Nienartowicz, M

    2000-01-01

    In the Clinic of Gastrointestinal Surgery at the Medical University in Wroc?aw in 402 cases substernal oesophageal reconstruction was performed using different pedunculated oesophageal substitutes. 63 patients had to be operated on for the second time because of disorders in the oesophageal substitute. In 13 cases stenosis in the upper anastomosis and in 3 patients stenosis in the anastomosis with stomach were corrected. In 7 cases oesophageal ulcer was excised. 6 patients were operated because of substitute herniation into pleural cavity. In 3 cases huge diverticula in the neck were removed. 5 patients were operated because of stomach outlet stenosis. In 15 cases operation was necessary to correct the sequel of reflux oesophagitis. In 8 cases the surgery was performed to remove stenosis of the substitute. In 2 cases there was torsion of substitute and in the other 2 cases postoperative stenosis was caused by adhesions. One patient was operated because of the dumping syndrome. In 2 patients with the colon substitute polyps from the segment used for the oesophagus were removed endoscopically. The mortality after corrective surgery on the oesophageal substitute was less than 10% (6/63). PMID:10946599

  12. Sugar substitutes during pregnancy

    PubMed Central

    Pope, Eliza; Koren, Gideon; Bozzo, Pina

    2014-01-01

    Abstract Question I have a pregnant patient who regularly consumes sugar substitutes and she asked me if continuing their use would affect her pregnancy or child. What should I tell her, and are there certain options that are better for use during pregnancy? Answer Although more research is required to fully determine the effects of in utero exposure to sugar substitutes, the available data do not suggest adverse effects in pregnancy. However, it is recommended that sugar substitutes be consumed in moderate amounts, adhering to the acceptable daily intake standards set by regulatory agencies. PMID:25392440

  13. In situ synthesis of magnesium-substituted biphasic calcium phosphate and in vitro biodegradation

    SciTech Connect

    Kim, Tae-Wan; Lee, Hyeong-Shin; Kim, Dong-Hyun; Jin, Hyeong-Ho [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)] [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Hwang, Kyu-Hong [School of Nano and Advanced Materials, Gyeongsang National University, Jinju, Kyungnam 660-701 (Korea, Republic of)] [School of Nano and Advanced Materials, Gyeongsang National University, Jinju, Kyungnam 660-701 (Korea, Republic of); Lee, Jong Kook [Department of Advanced Materials Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of)] [Department of Advanced Materials Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of); Park, Hong-Chae [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)] [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Yoon, Seog-Young, E-mail: syy3@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)] [School of Materials Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2012-09-15

    Highlights: ? Mg–BCP were successfully prepared through in situ aqueous co-precipitation method. ? The amount of ?-TCP phase was changed with the magnesium substitution level. ? The substitution of magnesium led to a decrease in the unit cell volume. ? Mg–BCP could be able to develop a new apatite phase on the surface faster than BCP. -- Abstract: In situ preparation of magnesium (Mg) substituted biphasic calcium phosphate (BCP) of hydroxyapatite (HAp)/?-tricalcium phosphate (?-TCP) were carried out through aqueous co-precipitation method. The concentrations of added magnesium were varied with the calcium in order to obtain constant (Ca + Mg)/P ratios of 1.602. X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy were used to characterize the structure of synthesized magnesium substituted BCP powders. The results have shown that substitution of magnesium in the calcium deficient apatites revealed the formation of biphasic mixtures of different HAp/?-TCP ratios after heating at 1000 °C. The ratios of the formation of phase mixtures were dependent on the content of magnesium. After immersing in Hanks’ balanced salt solution (HBSS) for 1 week, 1 wt% magnesium substituted BCP powders were degraded and precipitation started to be formed with small granules consisting of number of flake-like crystal onto the surface of synthesized powders. On the other hand, in the case of pure BCP powders, the formation of new precipitates was detected after immersion in HBSS for 2 weeks. On the basis of these results, magnesium substituted BCP could be able to develop a new apatite phase on the surface in contact with physiological fluids faster than BCP does. In addition, the retention time to produce the new apatite phase in implantation operation for the BCP powder could be controlled by the amount of magnesium substitution.

  14. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721...naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance...naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is...

  15. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721...naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance...naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is...

  16. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721...naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance...naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is...

  17. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721...naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance...naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is...

  18. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721...naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance...naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is...

  19. Sugar Substitutes: Aspartame

    MedlinePLUS

    ... sugar substitute. It is a combination of 2 amino acids: aspartic acid and phenylalanine. It is about 200 ... to metabolize phenylalanine, which is one of the amino acids in aspartame. If you are concerned that consuming ...

  20. Hydroxymethylation of ?-substituted nitroacetates

    Microsoft Academic Search

    Cong-Bin Ji; Yun-Lin Liu; Zhong-Yan Cao; Yi-Yu Zhang; Jian Zhou

    2011-01-01

    Only 1mol% of K3PO4 is efficient enough to catalyze the hydroxymethylation of ?-substituted nitroacetates in good to excellent yield. Both aliphatic and aryl substituted nitroacetates work well under this reaction. The first catalytic asymmetric version of this reaction also reported that 10mol% of cupreidine could catalyze this reaction up to 71% ee and 89% yield. Paraformaldehyde and formalin could both

  1. Black Voices

    ERIC Educational Resources Information Center

    McGowan, Jr., Martin J.

    1969-01-01

    "A television show by blacks for blacks--coupled with a program of training for black television technicians--was the basic concept of the Black Voices" series aired over KTCA-TV and KTCI-TV in Minneapolis and St. Paul during the 1968-1969 television season. The series was designed to provide understanding among blacks of the Twin Cities as well…

  2. Chemical reactions of metal powders with organic and inorganic liquids during ball milling

    NASA Technical Reports Server (NTRS)

    Arias, A.

    1975-01-01

    Chromium and/or nickel powders were milled in metal chlorides and in organic liquids representative of various functional groups. The powders always reacted with the liquid and became contaminated with elements from them. The milled powders had specific surface areas ranging from 0.14 to 37 sq m/g, and the total contamination with elements from the milling liquid ranged from 0.01 to 56 weight percent. Compounds resulting from substitution, addition, or elimination reactions formed in or from the milling liquid.

  3. Comminution of stainless steel powders

    Microsoft Academic Search

    B. A. Borok; R. P. Schchegoleva; L. S. Golubeva; F. S. Sariadi; E. M. Rabinovich

    1974-01-01

    1.Atmospheric milling in barrel type mixers at a powder-to-ball weight ratio of 1::2 is an effective means of comminuting stainless steel powders produced by the coreduction process. In the work described, milling for 27 h was found to increase the amount of the -0.063-mm fraction from ~15 to ~75% for a Kh18N15 steel powder and from ~24.6 to ~70%for a

  4. Polymer powder prepregging: Scoping study

    NASA Technical Reports Server (NTRS)

    Throne, James L.

    1988-01-01

    Early on, it was found that NEAT LARC-TPI thermoplastic polyimide powder behaved elastoplastically at pressures to 20 ksi and temperatures to 260 degrees celcius (below MP). At high resin assay, resin powder could be continuously cold-flowed around individual carbon fibers in a metal rolling mill. At low resin assay (2:1, C:TPI), fiber breakage was prohibitive. Thus, although processing of TPI below MP would be quite unique, it appears that the polymer must be melted and flowed to produce low resin assay prepreg. Fiber tow was spread to 75 mm using a venturi slot tunnel. This allowed intimate powder/fiber interaction. Two techniques were examined for getting room temperature powder onto the room temperature fiber surface. Electrostatic powder coating allows the charged powder to cling tenaciously to the fiber, even while heated with a hot air gun to above its melt temperature. A variant of the wet slurry coating process was also explored. The carbon fibers are first wetted with water. Then dry powder is sprinkled onto the wet tow and doctor-rolled between the fibers. The wet structure is then taken onto a heated roll, with hot air guns drying and sinter-melting the powder onto the fiber surfaces. In both cases SEM shows individual fibers coated with powder particles that have melted in place and flowed along the fiber surface via surface tension.

  5. Magnetic and Magnetoelastic Properties of Chromium Substituted Cobalt Ferrite

    Microsoft Academic Search

    C. Lo; P. Matlage; Y. Melikhov; J. Snyder; S. Song; D. Jiles

    2006-01-01

    In the present study, A series of polycrystalline chromium-substituted cobalt ferrite samples with compositions of CoCrxFe2-xO4 were prepared by standard powder ceramic techniques. The microstructure and final composition of the samples were characterized using a scanning electron microscope with energy-dispersive X-ray spectroscopy (EDX). The crystal structure of the samples was determined by X-ray diffractometry to be cubic spinel. Curie temperature,

  6. Preparation of fluoride substituted apatite cements as the building blocks for tooth enamel restoration

    Microsoft Academic Search

    Jie Wei; Jiecheng Wang; Xiaochen Liu; Jian Ma; Changsheng Liu; Jing Fang; Shicheng Wei

    2011-01-01

    Fluoride substituted apatite cement (fs-AC) was synthesized by using the cement powders of tetracalcium phosphate (TTCP) and sodium fluoride (NaF), and the cement powders were mixed with diluted phosphoric acid (H3PO4) as cement liquid to form fs-AC paste. The fs-AC paste could be directly filled into the carious cavities to repair damaged dental enamel. The results indicated that the fs-AC

  7. Infrared studies of apatites. I. Vibrational assignments for calcium, strontium, and barium hydroxyapatities utilizing isotopic substitution

    Microsoft Academic Search

    B. O. Fowler

    1974-01-01

    The infrared spectra of powdered calcium hydroxyapatite isotopically ; substituted with D, ¹⁸O, ⁴⁴Ca, and ⁴⁸Ca and infrared spectra of ; powdered strontium and barium hydroxyapatites and their deuterated analogs are ; reported at 48 and - 185 deg in the 4000-200cm-¹ region. Band ; assignments, based on isotopic frequency shifts, band intensity, band temperature ; dependency, and comparisons between

  8. 40 CFR 721.3063 - Substituted phenyl azo substituted phenyl esters (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Substituted phenyl azo substituted phenyl esters (generic name). 721.3063 Section...Substituted phenyl azo substituted phenyl esters (generic name). (a) Chemical substance...substituted phenyl azo substituted phenyl esters (PMNs P-95-655,...

  9. Characterization of mutagenic activity in grain-based coffee-substitute blends and instant coffees

    SciTech Connect

    Johansson, M.A.E.; Knize, M.G.; Felton, J.S.; Jagerstad, M.

    1994-06-01

    Several grain-based coffee-substitute blends and instant coffees showed a mutagenic response in the Ames/Salmonella test using TA98, YG1024 and YG1O29 with metabolic activation. The beverage powders contained 150 to 500 TA98 and 1150 to 4050 YG1024 revertant colonies/gram, respectively. The mutagenic activity in the beverage powders was shown to be stable to heat and the products varied in resistance to acid nitrite treatment. Characterization of the mutagenic activity, using HPLC-and the Ames test of the collected fractions, showed the coffee-substitutes and instant coffees contain several mutagenic compounds, which are most likely aromatic amines.

  10. Compressed iron powder core for electric motors

    Microsoft Academic Search

    K. Fukui; I. Watanabe; M. Morita

    1972-01-01

    The magnetic properties of compressed powder cores made of iron powder with high compressibility were investigated with the goal of making them practical in electric motors. An electrolytic iron powder and an atomized iron powder with a finely powdered resin were compacted under a pressure of 6 tons\\/cm2. The influence of iron particle size on magnetic properties was more marked

  11. Black Saturn

    E-print Network

    Henriette Elvang; Pau Figueras

    2007-04-03

    Using the inverse scattering method we construct an exact stationary asymptotically flat 4+1-dimensional vacuum solution describing Black Saturn: a spherical black hole surrounded by a black ring. Angular momentum keeps the configuration in equilibrium. Black saturn reveals a number of interesting gravitational phenomena: (1) The balanced solution exhibits 2-fold continuous non-uniqueness for fixed mass and angular momentum; (2) Remarkably, the 4+1d Schwarzschild black hole is not unique, since the black ring and black hole of black saturn can counter-rotate to give zero total angular momentum at infinity, while maintaining balance; (3) The system cleanly demonstrates rotational frame-dragging when a black hole with vanishing Komar angular momentum is rotating as the black ring drags the surrounding spacetime. Possible generalizations include multiple rings of saturn as well as doubly spinning black saturn configurations.

  12. Aryl substitution of pentacenes

    PubMed Central

    Waterloo, Andreas R; Sale, Anna-Chiara; Lehnherr, Dan; Hampel, Frank

    2014-01-01

    Summary A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films), thermoanalytical methods (DSC and TGA), cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives). X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices. PMID:25161729

  13. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Buffered penicillin powder, penicillin powder with buffered aqueous diluent. 520...FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered...

  14. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with buffered aqueous diluent. 520...FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered...

  15. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Buffered penicillin powder, penicillin powder with buffered aqueous diluent. 520...FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered...

  16. A multi-analytical approach for the characterization of powders from the Pompeii archaeological site

    Microsoft Academic Search

    Carmen Canevali; Paolo Gentile; Marco Orlandi; Francesca Modugno; Jeannette Jacqueline Lucejko; Maria Perla Colombini; Laura Brambilla; Sara Goidanich; Chiara Riedo; Oscar Chiantore; Pietro Baraldi; Cecilia Baraldi; Maria Cristina Gamberini

    Nine black powders found in Pompeii houses in three different types of bronze vessels (cylindrical theca atramentaria, unguentaries,\\u000a and aryballoi) were characterized in order to assess a correspondence between the composition and the type of vessel and,\\u000a possibly, to verify if these powders were inks or not. For the compositional characterization, a multi-analytical approach\\u000a was adopted, which involved the use

  17. Light extinction in metallic powder beds: Correlation with powder structure

    SciTech Connect

    Rombouts, M.; Froyen, L.; Gusarov, A.V.; Bentefour, E.H.; Glorieux, C. [Department Metaalkunde en Toegepaste Materiaalkunde, Katholieke Universiteit Leuven, Kasteelpark Arenberg 44, 3001 Leuven (Belgium); Baikov Institute of Metallurgy, Russian Academy of Sciences, Leninsky Prospect 49, 119991 Moscow (Russian Federation); Laboratorium voor Akoestiek en Thermische Fysica, Department Natuurkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Leuven (Belgium)

    2005-07-01

    A theoretical correlation between the effective extinction coefficient, the specific surface area, and the chord length distribution of powder beds is verified experimentally. The investigated powder beds consist of metallic particles of several tens of microns. The effective extinction coefficients are measured by a light-transmission technique at a wavelength of 540 nm. The powder structure is characterized by a quantitative image analysis of powder bed cross sections resulting in two-point correlation functions and chord length distributions. The specific surface area of the powders is estimated by laser-diffraction particle-size analysis and by the two-point correlation function. The theoretically predicted tendency of increasing extinction coefficient with specific surface area per unit void volume is confirmed by the experiments. However, a significant quantitative discrepancy is found for several powders. No clear correlation of the extinction coefficient with the powder material and particle size, and morphology is revealed, which is in line with the assumption of geometrical optics.

  18. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Copper powder. 73.2647 Section 73...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

  19. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Aluminum powder. 73.2645 Section 73...CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in...

  20. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Aluminum powder. 73.1645 Section 73.1645...CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely...

  1. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Aluminum powder. 73.1645 Section 73.1645...CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely...

  2. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Aluminum powder. 73.2645 Section 73...CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in...

  3. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Aluminum powder. 73.2645 Section 73...CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in...

  4. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Aluminum powder. 73.2645 Section 73...CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in...

  5. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Aluminum powder. 73.1645 Section 73.1645...CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely...

  6. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Aluminum powder. 73.2645 Section 73...CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in...

  7. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Aluminum powder. 73.1645 Section 73.1645...CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely...

  8. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Aluminum powder. 73.1645 Section 73.1645...CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely...

  9. Tactile sensory substitution studies.

    PubMed

    Bach-y-Rita, Paul

    2004-05-01

    Forty years ago a project to explore late brain plasticity was initiated that was to lead into a broad area of sensory substitution studies. The questions at that time were: Can a person who has never seen learn to see as an adult? Is the brain sufficiently plastic to develop an entirely new sensory system? The short answer to both questions is yes, first clearly demonstrated in 1969 ((Bach-y-Rita et al., 1969)). To reach that conclusion, it was first necessary to find a way to get visual information to the brain. That took many years and is still the most challenging aspect of the research and the development of practical sensory substitution and augmentation systems. The sensor array is not a problem: a TV camera for blind persons; an accelerometer for persons with vestibular loss; a microphone for deaf persons. These are common and fully developed devices. The problem is the brain-machine interface (BMI). In this short report, only two substitution systems are discussed, vision and vestibular substitution. PMID:15194608

  10. The Age of Substitutability

    ERIC Educational Resources Information Center

    Goeller, H. E.; Weinberg, Alvin M.

    1976-01-01

    Dwindling mineral resources might cause a shift from nonrenewable resources to renewable resources and inexhaustible elements such as iron and aluminum. Alternative energy sources such as breeder, fusion, solar, and geothermal power must be developed for production and recycling of materials. Substitution and, hence, living standards ultimately…

  11. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, R.

    1998-08-04

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products. 7 figs.

  12. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath (Littleton, CO); Blaugher, Richard D. (Evergreen, CO)

    1995-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals, such as nitrate salts of thallium, barium, calcium, and copper, which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of thallium in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  13. powder in water

    NASA Astrophysics Data System (ADS)

    Chan, Ya-Ting; Wu, Chao-Hsien; Shen, Pouyan; Chen, Shuei-Yuan

    2014-09-01

    Submicron-sized NiAl2+ X O4 fragments and nanocondensates of Ni-doped ?-Al2O3, Al-doped NiO and ?-Ni(OH)2 were synthesized simultaneously by pulsed laser ablation of NiAl2O4 powder in water and characterized using X-ray/electron diffraction and optical spectroscopy. The NiAl2+ X O4 is Al-enriched spinel with dislocations and subgrains. The Ni-doped ?-Al2O3 spinel has paracrystalline distribution (i.e., with fair constant longitudinal spacing, but variable relative lateral translations) of defect clusters and intimate intergrowth of ?-Al2O3 and 2x(3) commensurate superstructure. The Al-doped NiO has perfect cubo-octahedron shape and as small as 5 nm in size. The ?-Ni(OH)2 and 1-D turbostratic hydroxide lamellae occurred as a matrix of these oxide nanoparticles. The colloidal suspension containing the composite phases has a minimum band gap of 5.3 eV for potential photocatalytic applications.

  14. Silica powders for powder evacuated thermal insulating panel and method

    DOEpatents

    Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)

    1994-01-01

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

  15. Silica powders for powder evacuated thermal insulating panel and method

    DOEpatents

    Harris, M.T.; Basaran, O.A.; Kollie, T.G.; Weaver, F.J.

    1996-01-02

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm{sup 3} and an external surface area in the range of about 90 to 600 m{sup 2}/g is described. The silica powders are prepared by reacting a tetraalkyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders. 2 figs.

  16. Silica powders for powder evacuated thermal insulating panel and method

    DOEpatents

    Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)

    1996-01-01

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

  17. Silica powders for powder evacuated thermal insulating panel and method

    DOEpatents

    Harris, Michael T. (Knoxville, TN); Basaran, Osman A. (Oak Ridge, TN); Kollie, Thomas G. (Oak Ridge, TN); Weaver, Fred J. (Knoxville, TN)

    1995-01-01

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

  18. Method for molding ceramic powders

    DOEpatents

    Janney, Mark A. (Knoxville, TN)

    1990-01-01

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  19. Method for molding ceramic powders

    DOEpatents

    Janney, M.A.

    1990-01-16

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, where after the product may be sintered.

  20. Shock compaction of molybdenum powder

    NASA Technical Reports Server (NTRS)

    Ahrens, T. J.; Kostka, D.; Vreeland, T., Jr.; Schwarz, R. B.; Kasiraj, P.

    1983-01-01

    Shock recovery experiments which were carried out in the 9 to 12 GPa range on 1.4 distension Mo and appear adequate to compact to full density ( 45 (SIGMA)m) powders were examined. The stress levels, however, are below those calculated to be from 100 to approx. 22 GPa which a frictional heating model predicts are required to consolidate approx. 10 to 50 (SIGMA)m particles. The model predicts that powders that have a distension of m=1.6 shock pressures of 14 to 72 GPa are required to consolidate Mo powders in the 50 to 10 (SIGMA)m range.

  1. Exfoliation and thermal transformations of Nb-substituted layered titanates

    SciTech Connect

    Song Haiyan; Sjastad, Anja O.; Fjellvag, Helmer; Okamoto, Hiroshi [Department of Chemistry and Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo (Norway); Vistad, Ornulv B.; Arstad, Bjornar [SINTEF Materials and Chemistry, P.O. Box 124, Blindern, N-0314 Oslo (Norway); Norby, Poul, E-mail: pnor@risoe.dtu.dk [Department of Chemistry and Centre for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo (Norway); Materials Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, P.O. Box 49, DK-4000 Roskilde (Denmark)

    2011-12-15

    Single-layer Nb-substituted titanate nanosheets of ca. 1 nm thickness were obtained by exfoliating tetrabutylammonium (TBA)-intercalated Nb-substituted titanates in water. AFM images and turbidity measurements reveal that the exfoliated nanosheets crack and corrugate when sonicated. Upon heating, the thermal transformation into anatase and further to rutile is retarded. This suppression of the phase transition upon higher valent substitution may promote technological applications of anatase thin films, hereunder development of films with TCO properties. Depending on the oxygen partial pressure during the transformation, the Nb-substitution into TiO{sub 2} provokes different defect situations and also electronic properties. At reducing conditions, Nb is incorporated as Nb{sup V} and an equivalent amount of Ti{sup IV} is transformed to Ti{sup III} as evidenced by XPS. Magnetic susceptibility data show accordingly paramagnetic behavior. For samples heated in air Ti{sup IV} and Nb{sup V} cations prevail, the latter is compensated by cation vacancies. {sup 93}Nb MAS NMR data prove that Nb is finely dispersed into the transformed (Ti,Nb)O{sub 2} oxide matrices without sign of Nb{sub 2}O{sub 5} (nano)precipitates. The Nb-O-Ti bonds and defects at cation sites are considered key factors for increasing the transformation temperatures for conversion of the nanosheets to anatase and finally into rutile. It is further tempting to link the delay in crystallization to morphology limitations originating from the nanosheets. The present work shows that layered Nb-titanates are appropriate precursors for formation of highly oriented Nb-substituted anatase thin films via delamination, reconstruction and subsequent heat treatment. - Graphical abstract: Layered Nb-titanates are appropriate precursors for formation of highly oriented Nb-substituted anatase thin films via delamination, reconstruction and subsequent heat treatment. Highlights: Black-Right-Pointing-Pointer Single layer Nb-substituted nanosheets were obtained by exfoliation of layered titanates. Black-Right-Pointing-Pointer Nb(V) successfully introduced into anatase and rutile solid solutions. Black-Right-Pointing-Pointer Anatase obtained from reconstructed nanosheets exhibit enhanced thermal stability. Black-Right-Pointing-Pointer Oxygen partial pressure influences the valence of Nb in heat-treated samples. Black-Right-Pointing-Pointer Deposition of oriented thin Ti(Nb)O{sub 2} layers by spray coating was demonstrated.

  2. Structural studies of magnesium nitride fluorides by powder neutron diffraction

    SciTech Connect

    Brogan, Michael A. [School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hughes, Robert W. [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Smith, Ronald I. [ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Gregory, Duncan H., E-mail: Duncan.Gregory@glasgow.ac.uk [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2012-01-15

    Samples of ternary nitride fluorides, Mg{sub 3}NF{sub 3} and Mg{sub 2}NF have been prepared by solid state reaction of Mg{sub 3}N{sub 2} and MgF{sub 2} at 1323-1423 K and investigated by powder X-ray and powder neutron diffraction techniques. Mg{sub 3}NF{sub 3} is cubic (space group: Pm3m) and has a structure related to rock-salt MgO, but with one cation site vacant. Mg{sub 2}NF is tetragonal (space group: I4{sub 1}/amd) and has an anti-LiFeO{sub 2} related structure. Both compounds are essentially ionic and form structures in which nitride and fluoride anions are crystallographically ordered. The nitride fluorides show temperature independent paramagnetic behaviour between 5 and 300 K. - Graphical abstract: Definitive structures of the ternary magnesium nitride fluorides Mg{sub 3}NF{sub 3} and the lower temperature polymorph of Mg{sub 2}NF have been determined from powder neutron diffraction data. The nitride halides are essentially ionic and exhibit weak temperature independent paramagnetic behaviour. Highlights: Black-Right-Pointing-Pointer Definitive structures of Mg{sub 3}NF{sub 3} and Mg{sub 2}NF were determined by neutron diffraction. Black-Right-Pointing-Pointer Nitride and fluoride anions are crystallographically ordered in both structures. Black-Right-Pointing-Pointer Both compounds exhibit weak, temperature independent paramagnetic behaviour. Black-Right-Pointing-Pointer The compounds are essentially ionic with ionicity increasing with F{sup -} content.

  3. Ceramic powder for sintering materials

    NASA Technical Reports Server (NTRS)

    Akiya, H.; Saito, A.

    1984-01-01

    Surface activity of ceramic powders such as MgO and Al2O3, for use in sintering with sp. emphasis on their particle size, shape, particle size distribution, packing, and coexisting additives and impurities are reviewed.

  4. Rotary powder feed through apparatus

    DOEpatents

    Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

    2001-01-01

    A device for increasing the uniformity of solids within a solids fabrication system, such as a direct light fabrication (DLF) system in which gas entrained powders are passed through the focal point of a moving high-power light which fuses the particles in the powder to a surface being built up in layers. The invention provides a feed through interface wherein gas entrained powders input from stationary input lines are coupled to a rotating head of the fabrication system. The invention eliminates the need to provide additional slack in the feed lines to accommodate head rotation, and therefore reduces feed line bending movements which induce non-uniform feeding of gas entrained powder to a rotating head.

  5. Luminescence of powdered uranium glasses

    NASA Technical Reports Server (NTRS)

    Eubanks, A. G.; Mcgarrity, J. M.; Silverman, J.

    1974-01-01

    Measurement of cathodoluminescence and photoluminescence efficiencies in powdered borosilicate glasses having different particle size and different uranium content. Excitation with 100 to 350 keV electrons and with 253.7 nm light was found to produce identical absolute radiant exitance spectra in powdered samples. The most efficient glass was one containing 29.4 wt% B2O3, 58.8 wt% SiO2, 9.8 wt% Na2O and 2.0 wt% UO2.

  6. Method for Production of Powders

    NASA Technical Reports Server (NTRS)

    Stoltzfus, Joel M. (Inventor); Sircar, Subhasish (Inventor)

    1997-01-01

    Apparatus and method are disclosed for producing oxides of metals and of metal alloys. The metal or alloy is placed in an oxygen atmosphere in a combustion chamber and ignited. Products of the combustion include one or more oxides of the metal or alloy in powdered form. In one embodiment of the invention a feeder is provided whereby material to be oxidized by combustion can be achieved into a combustion chamber continuously. A product remover receives the powder product of the combustion.

  7. Neutron detectors comprising boron powder

    DOEpatents

    Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

    2013-05-21

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  8. Zirconia ceramics from coprecipitated powders

    Microsoft Academic Search

    I. Yu. Prokhorov

    1997-01-01

    The possibility was explored of making dense and strong partly stabilized zirconia (PSZ)-based ceramic materials from coprecipitated\\u000a zirconium and yttrium hydroxide powders of both factory and laboratory preparation. The effect of dry and wet grinding, powder\\u000a burning, cold isostatic pressure (CIP) at?0.8 GPa, and sintering at ?1600?C on the physicochemical properties of the material\\u000a was investigated. It was found that

  9. High-purity, fine-particle boron nitride powder synthesis at -75 to 750C. Report of investigations\\/1986

    Microsoft Academic Search

    Kalyoncu

    1986-01-01

    Nonoxide ceramics with improved high-temperature properties could substitute for high-temperature alloys and reduce the Nation's dependence on imports of Cr, Co, Ni, and Mn. To meet the objective, the Bureau of Mines conducted research to synthesize ultrafine reactive boron nitride (BN) powders. BN powders were prepared at temperatures ranging from -75 degrees to 750 degrees C. Low-temperature reactions (-75 to

  10. Powder collection apparatus/method

    DOEpatents

    Anderson, I.E.; Terpstra, R.L.; Moore, J.A.

    1994-01-11

    Device for separating and collecting ultrafine atomized powder from the gas stream of a gas atomizing apparatus comprises a housing having an interior wall oriented at an angle relative to horizontal so as to form a downwardly converging, conical expansion chamber, an inlet conduit communicated to the expansion chamber proximate an upper region thereof for receiving the gas stream, and an outlet proximate a lower region of the expansion chamber. The inlet conduit is oriented at a compound inclined angle (with respect to horizontal) selected to promote separation and collection of powder from the gas stream in the expansion chamber. The compound angle comprises a first entrance angle that is greater than the angle of repose of the powder on the housing interior wall such that any powder accumulation in the inlet conduit tends to flow down the wall toward the outlet. The second angle is selected generally equal to the angle of the housing interior wall measured from the same horizontal plane so as to direct the gas stream into the expansion chamber generally tangent to the housing interior wall to establish a downward swirling gas stream flow in the expansion chamber. A powder collection container is communicated to the outlet of the expansion chamber to collect the powder for further processing. 4 figures.

  11. Substitution: right or wrong?

    PubMed Central

    Barfield, J. C.

    1974-01-01

    Drug economy has always been and will continue to be important for hospitals. Substitution, as an aid to economy, requires reappraisal in the light of our developing knowledge of formulation and resultant bio-availability. The continued unqualified use of generic names in teaching and prescribing requires re-examination as a part of the problem and this highlights the need for better communication between medicine and pharmacy. PMID:4471371

  12. Asymmetric substitution masking Jiang & Chun1 Running title: Asymmetric substitution masking

    E-print Network

    Chun, Marvin M.

    Asymmetric substitution masking Jiang & Chun1 Running title: Asymmetric substitution masking Asymmetric object substitution masking Yuhong Jiang Marvin M. Chun Yale University Vanderbilt University. 232 Fax: (203)-624-4950 #12;Asymmetric substitution masking Jiang & Chun2 Abstract Object substitution

  13. Ceramic oxide powders and the formation thereof

    DOEpatents

    Katz, J.L.; Chenghung Hung.

    1993-12-07

    Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions. 14 figures.

  14. FABRICATION BEHAVIOR OF SOME URANIUM DIOXIDE POWDERS

    Microsoft Academic Search

    D. R. Stenquist; R. J. Anicetti

    1957-01-01

    The physical characteristics of uranium dioxide powders depend not only ; upon how they are prepared, but also upon the treatment of the powders prior to ; fabrication. Preliminary attempts to produce high-density sintered UOâ ; bodies demonstrated a wide range of sinterability among UOâ powders having ; different physical characteristics. Sintered densities of various UOâ ; powders varied from

  15. Powder lubrication of faults by powder rolls in gouge zones

    NASA Astrophysics Data System (ADS)

    Chen, X.; Madden, A. S.; Reches, Z.

    2013-12-01

    Powder-lubrication by fault gouge can be an effective mechanism of dynamic weakening of faults (Reches & Lockner, 2010); however, the physical mechanisms of this lubrication are poorly understood. While the flow of coarse-grained (> 100 ?m) materials, e.g. glass beads or quartz sand, was extensively studied, the flow of fine-grained (< 1 ?m) powders, e.g., fault-gouge and nano-powders, have remained enigmatic. We report here experimental results of a new efficient mechanism for powder lubrication. We conducted friction tests on high-velocity rotary shear apparatus (Reches & Lockner, 2010). Two types of experimental faults were tested: (1) faults made of solid, igneous rocks (granite, tonalite and diorite); and (2) fault-zones made of 2-3 mm thick layer of granular materials (oolites, calcite or gypsum) sheared in a confined cell. We performed 21 runs with total slip of 0.14-13 m, normal stress of 1.2-14.5 MPa, slip velocity of 0.012-0.97 m/s. The ultra-microscopic (SEM and AFM) analysis of the experimental slip surfaces revealed two outstanding features in 17 out of the 21 experiments: (1) localized fault-slip along Principal Slip Zones (PSZs) that are composed of a dense, shiny, cohesive crust, 0.5-1 micron thick, that overlaid a porous substrate, and (2) elongated rolls composed of gouge-powder into three-dimensional structures of closely-packed powder grains, (20-50 nm in size). The rolls are cylindrical, 0.75-1.4 micron wide, and 1.7-30 micron long, with smooth outer surface, and laminated, concentric layers of compacted grains. The rolls were exclusively found on the PSZs. Many rolls were destroyed fracturing and smearing on the PSZ, suggesting that the rolls underwent a life cycle of formation and destruction. Significant macroscopic friction reduction was measured in experiments with observed rolls, and no (or minor) friction reduction in the four experiments without rolls. The final, reduced friction coefficients have a general reciprocal relation to the rolls surface coverage, suggesting that increased development of rolls (= increasing surface coverage) enhanced fault weakening. We applied the Eldredge and Tabor (1955) model for rolling friction to the AFM observed morphology of the rolls and PSZs, and found good agreement between measured and modeled friction coefficients. We conclude that the measured friction reduction reflects a transition from sliding-dominated slip to rolling-dominated slip due to the presence and density of powder rolls. We further argue that powder rolling is an effective mechanism of powder lubrication, and that spontaneous growth of such rolls along crustal faults is likely to control earthquake weakening.

  16. Black tea

    MedlinePLUS

    Black tea is a product made from the Camellia sinesis plant. The aged leaves and stems are ... of the same plant, has some different properties. Black tea is used for improving mental alertness as ...

  17. Black psyllium

    MedlinePLUS

    Black psyllium is a weed that grows aggressively throughout the world. The plant was spread with the ... to make medicine. Be careful not to confuse black psyllium with other forms of psyllium including blond ...

  18. Black Psychology.

    ERIC Educational Resources Information Center

    Jones, Reginald L., Ed.

    The contents of the present volume, designed to bring together in a single place writings by the new black psychologists and other black social and behavioral scientists, are organized in seven parts, as follows: Part I, "Black Psychology: Perspectives," includes articles by Cedric Clark, Wade W. Nobles, Doris P. Mosby, Joseph White, and William…

  19. Black Appalachians.

    ERIC Educational Resources Information Center

    Waage, Fred, Ed.; Cabbell, Ed, Ed.

    1986-01-01

    This issue of "Now and Then" focuses on black Appalachians, their culture, and their history. It contains local histories, articles, and poems and short stories by Appalachian blacks. Articles include: "A Mountain Artist's Landscape," a profile of artist Rita Bradley by Pat Arnow; "A Part and Apart," a profile of black historian Ed Cabbell by Pat…

  20. Black Magic

    NSDL National Science Digital Library

    2010-01-01

    Most non-permanent markers use inks that are made of mixtures of colored pigments and water. How does Black Magic work? Why do some black inks separate into many colors on a wet coffee filter? Why does mixing many colors of ink make black?

  1. Synthesis, structure, thermal stability, mechanical and antibacterial behaviour of lanthanum (La³?) substitutions in ?-tricalciumphosphate.

    PubMed

    Meenambal, Rugmani; Singh, Ram Kishore; Nandha Kumar, P; Kannan, S

    2014-10-01

    Five different concentrations of lanthanum (La(3+)) substituted ?-tricalcium phosphate [?-TCP, ?-Ca3(PO4)2] were formed through aqueous precipitation technique and the results were compared with stoichiometric ?-TCP. All the La(3+) substituted ?-TCP powders were characterized using XRD, FT-IR, XRF, Raman spectroscopy and Rietveld refinement of the XRD data. The results from the investigation confirmed the presence of La(3+) in rhombohedral ?-TCP structure. The substitution of higher sized of La(3+) led to the considerable enhancement in lattice parameters of ?-TCP crystal structure and La(3+) was found to have occupied the eight fold coordinated Ca (3) site of ?-TCP structure. La(3+) occupancy at the Ca (3) site resulted in the significant distortions of the associated PO4 tetrahedra, which were supported by the Raman and FT-IR spectroscopic techniques. La(3+) presence in the crystal lattice of ?-TCP also led to the delay in allotropic phase transformation of ?-TCP to ?-TCP till 1300°C, thus signifying the good thermal stability of La(3+) substituted ?-TCP powders. The antibacterial efficiency of La(3+) substituted ?-TCP powders was confirmed from the in vitro tests done on microbes such as Staphylococcus aureus and Escheria coli. Further, the presence of La(3+) in the crystal lattice of ?-TCP did not affect the hardness and Young's modulus values of ?-TCP. PMID:25175254

  2. Flake tantalum powder for manufacturing electrolytic capacitors

    Microsoft Academic Search

    Jilin HE; Guoqi YANG; Luntao PAN; Hongdong LIU; Xifang BAO

    2008-01-01

    The FTP200 flake tantalum powder was introduced. The microstructures of the powder with leaf-like primary particles having an average flakiness of 2 to 20 and porous agglomerated particles were observed. The chemical composition, physical properties, and electrical properties of the FTP200 powder were compared with those of the FTW300 nodular powder. The FTP200 powder is more sinter-resistant, and the surface

  3. Synthesis of indium tin oxide (ITO) and fluorine-doped tin oxide (FTO) nano-powder by sol–gel combustion hybrid method

    Microsoft Academic Search

    Chi-Hwan Han; Sang-Do Han; Jihye Gwak; S. P. Khatkar

    2007-01-01

    ITO and FTO nano-powders were synthesized employing a new route sol–gel combustion hybrid method using acetylene black as a fuel. The dried gels exhibited an auto-catalytic combustion behavior. ITO and FTO nano-powders with narrow size distribution were obtained at 750 °C. Crystal structures were examined by powder X-ray diffraction (XRD) and particle morphology as well as crystal size was investigated by

  4. Polyimides comprising substituted benzidines

    NASA Technical Reports Server (NTRS)

    Harris, Frank W. (Inventor)

    1991-01-01

    A new class of polyimides and copolyimides made from substituted benzidines and aromatic dianhydrides and other aromatic diamines. The polyimides obtained with said diamines are distinguished by excellent thermal, excellent solubility, excellent electrical properties such as very low dielectric constants, excellent clarity and mechanical properties making the polyimides ideally suited as coating materials for microelectronic apparatii, as membranes for selective molecular or gas separation, as fibers in molecular composites, as high tensile strength, high compression strength fibers, as film castable coatings, or as fabric components.

  5. Trifluoromethyl-substituted polymers

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Current work sponsored by the grant at Southwest Texas State University is directed toward the synthesis and characterization of: (1) N-alkylated polyamides derived from o-fluorinated diacids; (2) highly fluorinated polyethers; (3) polyesters derived from 2-hydroxy-2-propyl substituted arenes and/or 2,5-difluoroterephthalic acid; and (4) silicon-containing fluoropolymers. Work during the period from 1 July to 31 Dec. 1993 focused primarily on items 3 and 4 and on the development of a phosphorus containing modification of '12F-PEK.'

  6. Synthesis of nanosized hydroxyapatite powders.

    PubMed

    Zarina, O; Radzali, O

    2004-05-01

    Hydroxyapatite powder was mechanochemically synthesized from calcium pyrophosphate (Ca2P2O7) and calcium carbonate (CaCO3) using a solid-state reaction. The two powders were mixed in distilled water, milled for 8 hours, dried and calcined at 1100 degrees C for 1 hour. The phase(s) formed was analyzed by x-ray diffraction (XRD). It was found that hydroxyapatite was not the only one formed. This result will be used as the starting point to produce a single-phase hydroxyapatite in terms of excess hydroxyl group in a mechanochemical reaction. PMID:15468867

  7. Thermal evolution behavior of carbides and {gamma} Prime precipitates in FGH96 superalloy powder

    SciTech Connect

    Zhang Lin, E-mail: zhanglincsu@163.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Liu Hengsan, E-mail: lhsj63@sohu.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); He Xinbo, E-mail: xb_he@163.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Rafi-ud-din, E-mail: rafiuddi@gmail.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Qu Xuanhui, E-mail: quxh@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Qin Mingli, E-mail: mlqin75@hotmail.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Li Zhou, E-mail: zhouli621@126.com [National Key Lab of High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing, 100095 (China); Zhang Guoqing, E-mail: g.zhang@126.com [National Key Lab of High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing, 100095 (China)

    2012-05-15

    The characteristics of rapidly solidified FGH96 superalloy powder and the thermal evolution behavior of carbides and {gamma} Prime precipitates within powder particles were investigated. It was observed that the reduction of powder size and the increase of cooling rate had transformed the solidification morphologies of atomized powder from dendrite in major to cellular structure. The secondary dendritic spacing was measured to be 1.02-2.55 {mu}m and the corresponding cooling rates were estimated to be in the range of 1.4 Multiplication-Sign 10{sup 4}-4.7 Multiplication-Sign 10{sup 5} K{center_dot}s{sup -1}. An increase in the annealing temperature had rendered the phase transformation of carbides evolving from non-equilibrium MC Prime carbides to intermediate transition stage of M{sub 23}C{sub 6} carbides, and finally to thermodynamically stable MC carbides. The superfine {gamma} Prime precipitates were formed at the dendritic boundaries of rapidly solidified superalloy powder. The coalescence, growth, and homogenization of {gamma}' precipitates occurred with increasing annealing temperature. With decreasing cooling rate from 650 Degree-Sign C{center_dot}K{sup -1} to 5 Degree-Sign C{center_dot}K{sup -1}, the morphological development of {gamma} Prime precipitates had been shown to proceed from spheroidal to cuboidal and finally to solid state dendrites. Meanwhile, a shift had been observed from dendritic morphology to recrystallized structure between 900 Degree-Sign C and 1050 Degree-Sign C. Moreover, accelerated evolution of carbides and {gamma}' precipitates had been facilitated by the formation of new grain boundaries which provide fast diffusion path for atomic elements. - Highlights: Black-Right-Pointing-Pointer Microstructural characteristic of FGH96 superalloy powder was investigated. Black-Right-Pointing-Pointer The relation between microstructure, particle size, and cooling rate was studied. Black-Right-Pointing-Pointer Thermal evolution behavior of {gamma} Prime and carbides in loose FGH96 powder was studied.

  8. Preparation and characterization of cobalt-substituted anthrax lethal factor

    SciTech Connect

    Saebel, Crystal E.; Carbone, Ryan; Dabous, John R.; Lo, Suet Y. [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada)] [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada); Siemann, Stefan, E-mail: ssiemann@laurentian.ca [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada)] [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer Cobalt-substituted anthrax lethal factor (CoLF) is highly active. Black-Right-Pointing-Pointer CoLF can be prepared by bio-assimilation and direct exchange. Black-Right-Pointing-Pointer Lethal factor binds cobalt tightly. Black-Right-Pointing-Pointer The electronic spectrum of CoLF reveals penta-coordination. Black-Right-Pointing-Pointer Interaction of CoLF with thioglycolic acid follows a 2-step mechanism. -- Abstract: Anthrax lethal factor (LF) is a zinc-dependent endopeptidase involved in the cleavage of mitogen-activated protein kinase kinases near their N-termini. The current report concerns the preparation of cobalt-substituted LF (CoLF) and its characterization by electronic spectroscopy. Two strategies to produce CoLF were explored, including (i) a bio-assimilation approach involving the cultivation of LF-expressing Bacillus megaterium cells in the presence of CoCl{sub 2}, and (ii) direct exchange by treatment of zinc-LF with CoCl{sub 2}. Independent of the method employed, the protein was found to contain one Co{sup 2+} per LF molecule, and was shown to be twice as active as its native zinc counterpart. The electronic spectrum of CoLF suggests the Co{sup 2+} ion to be five-coordinate, an observation similar to that reported for other Co{sup 2+}-substituted gluzincins, but distinct from that documented for the crystal structure of native LF. Furthermore, spectroscopic studies following the exposure of CoLF to thioglycolic acid (TGA) revealed a sequential mechanism of metal removal from LF, which likely involves the formation of an enzyme: Co{sup 2+}:TGA ternary complex prior to demetallation of the active site. CoLF reported herein constitutes the first spectroscopic probe of LF's active site, which may be utilized in future studies to gain further insight into the enzyme's mechanism and inhibitor interactions.

  9. Explicit Substitutions and All That

    NASA Technical Reports Server (NTRS)

    Ayala-Rincon, Mauricio; Munoz, Cesar; Busnell, Dennis M. (Technical Monitor)

    2000-01-01

    Explicit substitution calculi are extensions of the Lambda-calculus where the substitution mechanism is internalized into the theory. This feature makes them suitable for implementation and theoretical study of logic-based tools such as strongly typed programming languages and proof assistant systems. In this paper we explore new developments on two of the most successful styles of explicit substitution calculi: the lambda(sigma)- and lambda(s(e))-calculi.

  10. Explicit Substitutions and All That

    NASA Technical Reports Server (NTRS)

    Ayala-Rincon, Mauricio; Munoz, Cesar

    2000-01-01

    Explicit substitution calculi are extensions of the lambda-calculus where the substitution mechanism is internalized into the theory. This feature makes them suitable for implementation and theoretical study of logic-based tools such as strongly typed programming languages and proof assistant systems. In this paper we explore new developments on two of the most successful styles of explicit substitution calculi: the lambda sigma- and lambda S(e)-calculi.

  11. Rare-earth substitutions in Z-type hexaferrites

    NASA Astrophysics Data System (ADS)

    Jacquiod, Catherine; Autissier, Denis

    1992-02-01

    Z-type hexaferrite (Ba 3Co 2Fe 24O 41) presents a gyromagnetic permeability whose resonance frequency stands around 2 GHz. The damping coefficient ? is less than 0.1. The influence on the damping coefficient of doping this ferrite by a rare-earth (La) has been studied. Powders have been synthesized by carbonate coprecipitation, dried and calcined at different temperatures. Different phases have been characterized by X-ray diffraction and magnetization measurements. Solubility in the range of weak concentrations has been verified. The synthesized powders were processed by slip casting in the presence of a magnetic field in order to align the particles. The microstructural and hyperfrequency characteristics have been evaluated. The influence of the substitution on anisotropy fields and damping are studied in comparison with pure Co 2Z, whose processing and properties have been optimized as a reference.

  12. Rapid hydrothermal flow synthesis and characterisation of carbonate- and silicate-substituted calcium phosphates

    PubMed Central

    Knowles, Jonathan C; Rehman, Ihtesham; Darr, Jawwad A

    2013-01-01

    A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising phase pure carbonated hydroxyapatite (CO3-HA) with ?5?wt% substituted carbonate content (sample 7.5CO3-HA) and it was found that a further increase in urea concentration in solution resulted in biphasic mixtures of carbonate-substituted hydroxyapatite and calcium carbonate. Transmission electron microscopy images revealed that the particle size of hydroxyapatite decreased with increasing urea concentration. Energy-dispersive X-ray spectroscopy result revealed a calcium deficient apatite with Ca:P molar ratio of 1.45 (±0.04) in sample 7.5CO3-HA. For silicate-substituted hydroxyapatite (SiO4-HA) silicon acetate was used as a silicate ion source. It was observed that a substitution threshold of ?1.1?wt% exists for synthesis of SiO4-HA in the continuous hydrothermal flow synthesis system, which could be due to the decreasing yields with progressive increase in silicon acetate concentration. All the as-precipitated powders (without any additional heat treatments) were analysed using techniques including Transmission electron microscopy, X-ray powder diffraction, Differential scanning calorimetry, Thermogravimetric analysis, Raman spectroscopy and Fourier transform infrared spectroscopy. PMID:22983020

  13. Triboelectric charging of polymer powders in fluidization and transport processes

    Microsoft Academic Search

    J. R. Mountaint; D. L. Wankum; M. K. Mazumder; T. Chasser; P. Pettit

    1997-01-01

    Steady flow of powder at a desired rate is a necessity for controlling thickness and uniformity of the deposited powder layer in electrostatic spray painting. In most powder coating applications, the polymer powder is fluidized to transport the powder to the spray gun using a powder pump. The powder delivery tube is often long; sometimes in excess of 10 m.

  14. Brominated carbon black: An EDXD study

    SciTech Connect

    Carbone, Marilena [Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133 Roma (Italy); Gontrani, Lorenzo, E-mail: lorenzo.gontrani@uniroma1.it [CNR-Istituto di Struttura della Materia, Via del Fosso del Cavaliere, I-00133 Roma, Italy and Dipartimento di Chimica - Università La Sapienza, P.le Aldo Moro 5, I-00185 Roma (Italy)

    2014-06-19

    An energy dispersive X-Ray study of pure and brominated carbon black was carried out. The analysis of the diffraction patterns reveals that the low bromine load (ca.1% mol) is trapped into the structure, without significantly modifying it. This allows the application of the difference methods, widely tested for electrolyte solutions, inorganic matrices containing metals and isomorphic substitutions.

  15. POWDER COATINGS: A TECHNOLOGY REVIEW

    EPA Science Inventory

    In 1995, surface coatings accounted for nearly 2.55 million Mg of volatile organic compound (VOC) emissions nationally, which is more than 12% of VOC emissions from all sources. In recent years, powder coatings have been steadily gaining popularity as an alternative to solvent-bo...

  16. Pharmaceutically Engineering Powders Using FHMG

    Microsoft Academic Search

    G. Walker; S. Bell; M. Vann; H. Zhai; D. Jones; G. Andrews

    2007-01-01

    Fluidized hot melt granulation (FHMG) is an innovative granulation process that has distinct advantages over techniques that are typically used in the pharmaceutical industry for powder agglomeration and mixing. The aim of this research was to investigate process and formulation parameters that affect FHMG, in a pharmaceutical context, using Lutrol® F68 (copolymer of polyoxyethylene-polyoxypropylene) as a meltable binder with inert

  17. Thermal properties of carbon black aqueous nanofluids for solar absorption

    PubMed Central

    2011-01-01

    In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency. PMID:21767359

  18. Effect of the carbon addition to filling powder ball-milled with oils on the critical current density in ex situ processed MgB2 tapes

    NASA Astrophysics Data System (ADS)

    Fujii, H.; Ozawa, K.; Kitaguchi, H.

    2012-10-01

    We have studied the effect of planetary ball-milling of filling powder with mineral and silicon oils on the carbon substitution in MgB2 and the critical current density (Jc) of Fe-sheathed MgB2 tapes fabricated through an ex situ process in a powder-in-tube (PIT) technique. The mineral oil is much more effective for the carbon substitution and hence the Jc enhancement of tapes than the silicon oil. The silicon oil hardly refines MgB2 and causes a slight carbon substitution, compared with the mineral oil. Low-temperature drying of the as-milled powder to remove the mineral oil is more effective for the Jc enhancement due to an enhanced carbon substitution. This is probably because the low-temperature drying leaves more organic material from decomposed oil which acts as a carbon source. However, the carbon substitution amount is just x = 0.04-0.05 in MgB2-xCx. Although the carbon addition to filling powder is effective in increasing the carbon substitution, the Jc properties of tapes degrade due to induced weak coupling.

  19. Black Body

    Microsoft Academic Search

    Dieter Hoffmann

    A black body was first defined by Gustav R. Kirchhoff (1824–87) in 1859 as an object that absorbs all radiation falling upon\\u000a it. Such a conception of an ideal black body was crucial for understanding heat radiation and its laws. Since a completely\\u000a black body does not exist in nature, it had to be constructed. Kirchhoff had already suggested that

  20. Polymer quenched prealloyed metal powder

    DOEpatents

    Hajaligol, Mohammad R. (Midlothian, VA); Fleischhauer, Grier (Midlothian, VA); German, Randall M. (State College, PA)

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  1. Advanced composites take a powder

    SciTech Connect

    Holty, D.W. (Custom Composite Materials, Inc., Atlanta, GA (United States))

    1993-06-01

    To a professional chemist with more than 25 years of industrial experience, the world of advanced composites is a fascinating new venue. Here resins and fibers come together in a completely synergistic partnership, achieving marvels of strength and light weight that make advanced composite materials virtually the only solution for challenging applications. In the late 1980s, Professor John Muzzy of the Georgia Institute of Technology, was intrigued by the physical properties of thermoplastics, and he developed a new way to bring the thermoplastic resins together with high-performance fibers. As part of the work Muzzy did with Lockheed and NASA he demonstrated that electrostatic powder coating was an attractive new method for combining thermoplastic resins with reinforcing fibers. Presentation of this work by Lockheed at a government-industry conference led to a new project for Muzzy, sponsored by NASA Langley. Powder prepregging proved to be the attractive alternative that NASA was looking for. While working on powder prepregging with LaRC-TPI, Muzzy and his colleagues developed methods for exposing all of the fibers to the powder to improve the distribution of the resin on the tow, a continuous bundle of filaments. Optimal resin distribution was achieved by spreading the moving tow. A very flexible towpreg was produced by maintaining the spread tow through the powder coating chamber and into the oven, where the resin particles were fused to the individual filaments. Muzzy's invention has enabled Custom Composite Materials, Inc. to offer resin/fiber combinations based on thermoplastic resins such as nylon and polypropylene. Beyond the expected advantages over epoxy thermoset systems, they are beginning to exploit a fundamental property of thermoplastic resins: viscoelasticity, which can be defined as the resistance to flow as a function of applied stress. Thermoplastics have a much higher viscoelasticity than thermosets.

  2. Black Smokers

    NSDL National Science Digital Library

    Black Smokers explains the phenomena of deep-sea hydrothermal vents that occur under oceans within mid-ocean ridge volcanoes. The site describes deep-sea hydrothermal vent life forms, the ocean floor, and the mid-ocean ridge system. Teacher resources include games and lesson plans about the human impact on black smoker environments, the debate on human versus robotic expeditions, tools and engineering for black smoker expeditions, and how oceanic crust forms and ages. There are reports from expeditions studying black smokers and information on the research vessels and other underwater tools of the expeditions.

  3. Peierls substitution for magnetic Bloch bands

    E-print Network

    Silvia Freund; Stefan Teufel

    2013-12-20

    We consider the one-particle Schro\\"odinger operator in two dimensions with a periodic potential and a strong constant magnetic field perturbed by slowly varying non-periodic scalar and vector potentials, $\\phi(\\epsilon x)$ and $A(\\epsilon x)$, for $\\epsilon\\ll 1$. For each isolated family of magnetic Bloch bands we derive an effective Hamiltonian that is unitarily equivalent to the restriction of the Schro\\"odinger operator to a corresponding almost invariant subspace. At leading order, our effective Hamiltonian can be interpreted as the Peierls substitution Hamiltonian widely used in physics for non-magnetic Bloch bands. However, while for non-magnetic Bloch bands the corresponding result is well understood, both on a heuristic and on a rigorous level, for magnetic Bloch bands it is not clear how to even define a Peierls substitution Hamiltonian beyond a formal expression. The source of the difficulty is a topological obstruction: In contrast to the non-magnetic case, magnetic Bloch bundles are generically not trivializable. Thus, Peierls substitution Hamiltonians for magnetic Bloch bands turn out to be pseudo-differential operators acting on sections of non-trivial vector bundles over a two-torus, the reduced Brillouin zone. Part of our contribution is the construction of a suitable Weyl calculus for such operators. As an application we construct a family of canonical one-band Hamiltonians $H_\\theta$ for magnetic Bloch bands with Chern number $\\theta\\in\\mathbb{Z}$ that generalizes the Hofstadter model $H_{\\theta=0}$ for a single non-magnetic Bloch band. It turns out that the spectrum of $H_\\theta$ is independent of $\\theta$ and thus agrees with the Hofstadter spectrum depicted in his famous (black and white) butterfly. However, the resulting Chern numbers of subbands, corresponding to Hall conductivities, depend on $\\theta$, and thus the models lead to different colored butterflies.

  4. ER Physician Raises Concerns about Powdered Caffeine

    MedlinePLUS

    ... experts. The main difference between powdered and liquid alcohol is its packaging. The powder may be more convenient to pack and carry, but it's not a concentrated form of alcohol. Critics warn however, young people may be tempted ...

  5. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity...Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye,...

  6. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity...Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye,...

  7. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity...Copper powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye,...

  8. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity...Copper powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye,...

  9. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity...Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye,...

  10. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity...Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye,...

  11. Intradermal needle-free powdered drug injection

    E-print Network

    Liu, John (John Hsiao-Yung)

    2012-01-01

    This thesis presents a new method for needle-free powdered drug injection. The design, construction, and testing of a bench-top helium-powered device capable of delivering powder to controllable depths within the dermis ...

  12. Displacement, Substitution, Sublimation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

  13. Review: aqueous tape casting of ceramic powders

    Microsoft Academic Search

    D. Hotza; P. Greil

    1995-01-01

    Slurry formulations and processing parameters of the water-based tape casting of ceramic powders are reviewed. Additives include binders, like cellulose ethers, vinyl or acrylic-type polymers; plasticizers, like glycols; and dispersants, like ammonium salts of poly(acrylic acids). Mostly alumina powders have been employed. Hydrophobing of ceramic powders permits the aqueous processing even of water-reactive powders, like aluminium nitride. Non-toxicity and non-inflammability

  14. Processing and characterization of carob powder

    Microsoft Academic Search

    Ali K. Yousif; H. M. Alghzawi

    2000-01-01

    The possibility of processing roasted carob powder using different time–temperature combinations has been studied. The physical and chemical characteristics of the prepared carob powders were also examined. The most acceptable roasted carob powder was obtained by roasting kibbled carob at 150°C for 60 min. The roasted carob powder contained 9.00, 5.82, 2.84 and 0.74% moisture, protein, ash and fat, respectively.

  15. Calcium carbonate powder containing gentamicin for mixing with bone grafts.

    PubMed

    Coraça-Huber, Débora; Hausdorfer, Johann; Fille, Manfred; Nogler, Michael; Kühn, Klaus-Dieter

    2014-08-01

    Bone grafts are used for reconstructing bone defects caused by implant-associated complications, trauma, and tumors. Surgery with bone allografts is complex and time consuming; therefore, it is prone to a higher infection rate (2.0%-2.5%). In the case of site infection, systemically administered antibiotics cannot reach the infected bone graft. This study evaluated the use of resorbable bone graft substitute powder (HERAFILL; Heraeus Medical GmbH, Wehrheim, Germany) as a bone void-filling material as well as an antibiotic carrier for mixing with bone grafts. The antibiotic activity of the bone chips mixed with HERAFILL powder was measured by drug release tests and bacterial susceptibility with Bacillus subtilis, Staphylococcus epidermidis, and Staphylococcus aureus. HERAFILL powder was added to the bone chips (bone chips/HERAFILL; w/w = 1:1), mixed with a spatula, and vortexed for 1 minute. Gentamicin base release was evaluated in phosphate-buffered saline for up to 7 days using B subtilis bioassay. Antimicrobial efficacy was tested with S aureus and S epidermidis. The average amount of gentamicin base released from bone chips mixed with HERAFILL at 0 to 12 hours was 99.66 mg/mL. On day 7, the gentamicin base released 0.42 mg/mL. The elution released from bone chips mixed with HERAFILL promoted the formation of a zone of inhibition on S epidermidis and S aureus plates. This study confirmed the capacity of bone grafts to act as antibiotic carriers once mixed with HERAFILL powder. Bone chips mixed with HERAFILL showed efficacy against S aureus and S epidermidis. PMID:25102500

  16. LAND USE AND OWNERSHIP, POWDER RIVER BASIN

    E-print Network

    Chapter PM LAND USE AND OWNERSHIP, POWDER RIVER BASIN By T.T. Taber and S.A. Kinney In U........................................PM-1 Map Information for the Powder River Basin Land Use and Land Cover map...........................................................PM-2 Map Information for the Powder River Basin Subsurface Ownership map

  17. Electrodeposition of Fe powder from acid electrolytes

    Microsoft Academic Search

    VESNA M. MAKSIMOVI?; LJUBICA J. PAVLOVI?; BORKA M. JOVI?; MIOMIR G. PAVLOVI?

    2008-01-01

    Polarization characteristics of the electrodeposition processes of Fe powders from sulfate and chloride electrolytes and the morphology of the ob- tained powders were investigated. The morphology depended on the anion pre- sence in the electrolyte but not on the current density in the investigated range. A characteristic feature of the dendritic powder with cauliflower endings ob- tained from sulfate electrolyte

  18. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Copper powder. 73.1647 Section 73.1647...FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing...

  19. Energy aspects of iron powder production

    SciTech Connect

    Capus, J.M.

    1980-01-01

    An analysis is given of the energy consumption in the manufacture of iron powder by the Quebec Metal Powders Limited process. Some comparisons are made with earlier data for alternative processes. Finally some comments are made on energy conservation projects in the manufacture of iron powder. (MOW)

  20. April 11, 2013 Powder Consolidation under Pressure

    E-print Network

    Thomas, David D.

    April 11, 2013 Powder Consolidation under Pressure Wei-Jhe Sun Tablet, a consolidated powder structure, by considering the evolution of powder structure under compaction pressure.1 The mechanical, relative volume, and density to compaction pressure. A widely used equation is Heckel equation, which does

  1. FTIR and XRD evaluation of carbonated hydroxyapatite powders synthesized by wet methods

    Microsoft Academic Search

    Anna ?lósarczyk; Zofia Paszkiewicz; Czeslawa Paluszkiewicz

    2005-01-01

    Carbonated hydroxyapatite powders were obtained by wet method. The CO32? ions were introduced using NH4HCO3 and NaHCO3 in the amount of 0.1 or 0.05M. It was found by FTIR and X-ray studies that fraction of CO32? substitutions in the HAp structure and thermal stability of CHAp depends on the amount and type of carbonate additives. The significant decomposition of carbonated

  2. Are black holes totally black?

    E-print Network

    A. A. Grib; Yu. V. Pavlov

    2014-10-21

    Geodesic completeness needs existence near the horizon of the black hole of "white hole" geodesics coming from the region inside of the horizon. Here we give the classification of all such geodesics with the energies $E/m \\le 1$ for the Schwarzschild and Kerr's black hole. The collisions of particles moving along the "white hole" geodesics with those moving along "black hole" geodesics are considered. Formulas for the increase of the energy of collision in the centre of mass frame are obtained and the possibility of observation of high energy particles arriving from the black hole to the Earth is discussed.

  3. Baby Powder Use in Infant Skin CareParental Knowledge and Determinants of Powder Usage

    Microsoft Academic Search

    Gregory F. Hayden; George T. Sproul

    1984-01-01

    One hundred parents of infants aged 2 weeks to 6 months were surveyed at the time of routine well-child visits to assess parental knowledge about baby powder and to determine whether hospital policy of providing a free powder sample to newly delivered mothers was unwittingly promoting powder usage. Most parents (69%) reported regular baby powder use as part of routine

  4. How Do Substitute Teachers Substitute? An Empirical Study of Substitute-Teacher Labor Supply

    ERIC Educational Resources Information Center

    Gershenson, Seth

    2012-01-01

    This paper examines the daily labor supply of a potentially important, but often overlooked, source of instruction in U.S. public schools: substitute teachers. I estimate a sequential binary-choice model of substitute teachers' job-offer acceptance decisions using data on job offers made by a randomized automated calling system. Importantly, this…

  5. Black Holes

    NSDL National Science Digital Library

    The first website (1), created by the Department of Physics at Syracuse University, provides an educational, easily understandable explanation of the characteristics of a black hole. Students can learn the consequences a spacecraft would face if it traveled near or through the horizon of a black hole. The next website (2 ), created by the Amazing Space education group of the Space Telescope Science Institute's Office of Public Outreach, provides an online interactive exploration of black holes. Through this large, vibrant website, students can learn about stellar, supermassive, and miniature black holes. Teachers can find many amazing images, lesson plans, and other scientific background information. NASA created the next website (3) as a directory to many websites discussing black holes. Visitors can listen to the sound of a black hole, ask a NASA scientist questions, take a journey into a Black Hole, and much more. Wikipedia (4) investigates the questions related to how classical theories of thermodynamics are upheld within black holes. Students and educators will find links for many of the physical terms used within the descriptions to obtain further information. Robert M. Wald at the University of Chicago discusses Hawking radiation, the generalized second law, the thermodynamics of black holes, and entropy (5). This more advanced description provides numerous references and equations, as well as a discussion on issues the author feels are unresolved. J.E. Avron at the Israel Institute of Technology provides a straightforward discussion of the thermodynamics and entropy of black holes for those not familiar with the theory of general relativity (6). Through this pdf document, students can learn about the Planck scale, the temperature of black holes, and the LaPlace argument. The last two websites are online news articles describing the latest developments of black holes. After a fifty-three hour observation, NASA scientists have concluded that the central region of the Perseus galaxy cluster is producing sound waves with a frequency over a million billion times lower than the limits of human hearing (7). After learning how these sound waves are thought to have been created, visitors can view an animation of the waves generated in the Perseus Cluster. The last website (8), provided by space.com, investigates the question "If I had the opportunity to look at a black hole, would it look like a hole all the way around or just a hole above and below a funnel?" Visitors can also learn the about the spinning of black holes.

  6. Mesoscale Simulations of Powder Compaction

    NASA Astrophysics Data System (ADS)

    Lomov, Ilya.; Fujino, Don; Antoun, Tarabay; Liu, Benjamin

    2009-12-01

    Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

  7. MESOSCALE SIMULATIONS OF POWDER COMPACTION

    SciTech Connect

    Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore CA 94551 (United States)

    2009-12-28

    Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

  8. 14 CFR 1260.55 - Reports substitution.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.55 Reports substitution. Reports Substitution October 2000 Technical Reports may be substituted for the required Performance Reports. The title page of...

  9. 14 CFR 1260.55 - Reports substitution.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.55 Reports substitution. Reports Substitution October 2000 Technical Reports may be substituted for the required Performance Reports. The title page of...

  10. 14 CFR 1260.55 - Reports substitution.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.55 Reports substitution. Reports Substitution October 2000 Technical Reports may be substituted for the required Performance Reports. The title page of...

  11. 14 CFR 1260.55 - Reports substitution.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.55 Reports substitution. Reports Substitution October 2000 Technical Reports may be substituted for the required Performance Reports. The title page of...

  12. 14 CFR 1260.55 - Reports substitution.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.55 Reports substitution. Reports Substitution October 2000 Technical Reports may be substituted for the required Performance Reports. The title page of...

  13. 40 CFR 721.5867 - Substituted phenol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Substituted phenol. 721.5867 Section 721.5867 ...Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant...substance generically identified as substituted phenol (PMNs P-89-1125,...

  14. 40 CFR 721.9100 - Substituted quinoline.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Substituted quinoline. 721.9100 Section 721.9100...Substances § 721.9100 Substituted quinoline. (a) Chemical substance and significant...identified generically as substituted quinoline (PMN P-93-1183) is subject...

  15. 40 CFR 721.9100 - Substituted quinoline.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Substituted quinoline. 721.9100 Section 721.9100...Substances § 721.9100 Substituted quinoline. (a) Chemical substance and significant...identified generically as substituted quinoline (PMN P-93-1183) is subject...

  16. Composition of reactive powder concretes

    Microsoft Academic Search

    Pierre Richard; Marcel Cheyrezy

    1995-01-01

    Development of an ultra-high strength ductile concrete designated RPC (Reactive Powder Concrete), was made possible by the application of a certain number of basic principles relating to the composition, mixing and post-set heat curing of the concrete.RPC 200, which can be used under job site conditions similar to those for conventional high performance concretes, can be used in the construction

  17. Mesoscale simulations of powder compaction

    NASA Astrophysics Data System (ADS)

    Lomov, Ilya; Antoun, Tarabay; Liu, Benjamin

    2009-06-01

    Mesoscale 3D simulations of metal and ceramic powder compaction in shock waves have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating shock compaction of porous well-characterized ductile metal using Steinberg material model. Results of the simulations with handbook values for parameters of solid 2024 aluminum have good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not so well studied as metals, so material model for ceramic (tungsten carbide) has been fitted to shock compression experiments of non-porous samples and further calibrated to experimental match compaction curves. Direct simulations of gas gun experiments with ceramic powder have been performed and showed good agreement with experimental data. Numerical shock wave profile has same character and thickness as measured with VISAR. Numerical results show evidence of hard-to-explain reshock states above the single-shock Hugoniot line, which have also been observed in the experiments. We found that to receive good quantitative agreement with experiment it is essential to perform 3D simulations, since 2D results tend to underpredict stress levels for high-porosity powders regardless of material properties. We developed a process to extract macroscale information for the simulation which can be directly used in calibration of continuum model for heterogeneous media.

  18. Black holes

    E-print Network

    Piotr T. Chrusciel

    2002-01-16

    This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usual one for gravity, and leads to the one associated with the Unruh metric in the case of Euler equations. We review the global conditions which have been used in the Scri-based definition of a black hole and point out the deficiencies of the Scri approach. Various results on the structure of horizons and apparent horizons are presented, and a new proof of semi-convexity of horizons based on a variational principle is given. Recent results on the classification of stationary singularity-free vacuum solutions are reviewed. Two new frameworks for discussing black holes are proposed: a "naive approach", based on coordinate systems, and a "quasi-local approach", based on timelike boundaries satisfying a null convexity condition. Some properties of the resulting black holes are established, including an area theorem, topology theorems, and an approximation theorem for the location of the horizon.

  19. Injectability of brushite-forming Mg-substituted and Sr-substituted alpha-TCP bone cements.

    PubMed

    Pina, S; Torres, P M C; Ferreira, J M F

    2010-02-01

    The influence of magnesium- and strontium-substitutions on injectability and mechanical performance of brushite-forming alpha-TCP cements has been evaluated in the present work. The effects of Mg- and Sr-substitutions on crystalline phase composition and lattice parameters were determined through quantitative X-ray phase analysis and structural Rietveld refinement of the starting calcium phosphate powders and of the hardened cements. A noticeable dependence of injectability on the liquid-to-powder ratio (LPR), smooth plots of extrusion force versus syringe plunger displacement and the absence of filter pressing effects were observed. For LPR values up to 0.36 ml g(-1), the percentage of injectability was always higher and lower for Mg-containing cements and for Sr-containing cements, respectively, while all the pastes could be fully injected for LPR > 0.36 ml g(-1). The hardened cements exhibited relatively high wet compressive strength values (~17-25 MPa) being the Sr- and Mg-containing cements the strongest and the weakest, respectively, holding an interesting promise for uses in trauma surgery such as for filling bone defects and in minimally invasive techniques such as percutaneous vertebroplasty to fill lesions and strengthen the osteoporotic bone. PMID:19851845

  20. CALIFORNIA BLACK

    E-print Network

    Quercus Kelloggii Newberry; Alfred Brousseau

    tribal ethnicity. Wildlife: It is well known that bears (Ursus americanus), ground squirrels (Spermophilus scrofa), jays (Cyanocitta stelleri), band-tailed pigeons (Columba fasciata), acorn woodpeckers (Melanerpes formicivorus), pocket gophers (Thomomys bottae), deer mice (Peromyscus spp.) and black

  1. Powder neutron diffraction studies of a carbonate fluorapatite

    SciTech Connect

    Leventouri, Th. [Physics Department, Florida Atlantic University, Boca Raton, Florida 33431 (United States); Chakoumakos, B. C. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States); Moghaddam, H. Y. [Physics Department, Florida Atlantic University, Boca Raton, Florida 33431 (United States); Perdikatsis, V. [Institute of Geology and Mineral Exploration, Messogion 70, 11527 Athens, (Greece)

    2000-02-01

    Atomic positional disorder of a single-phase natural carbonate fluorapatite (francolite) is revealed from analysis of the atomic displacement parameters (ADPs) refined from neutron powder diffraction data as a function of temperature and carbonate content. The ADPs of the francolite show a strong disturbance at the P, O3, and F sites. When it is heat treated to partially or completely remove the carbonate, the ADPs as well as the other structural parameters resemble those of a fluorapatite (Harding pegmatite) that was measured under the same conditions. The various structural changes are consistent with a substitution mechanism whereby the planar carbonate group replaces a phosphate group and lies on the mirror plane of the apatite structure. (c) 2000 Materials Research Society.

  2. Dispersing agents for an aqueous slurry of coal powder

    SciTech Connect

    Moriyama, N.; Watanabe, S.; Yamamura, M.

    1981-11-24

    Aqueous dispersions of coal powder having good flowability properties are provided by employing, as the dispersing agent, an anionic surface active agent. The formula of the additives: (R-O-CH2CH2O-MSO3)nm wherein R is an alkyl or alkenyl group having 6 to 22 carbon atoms or an alkyl- or alkenyl-substituted aryl group having 4 to 22 carbon atoms in the substituent thereof, M is an integer from 2 to 50, N is a number of from 1 to 3 and is the same as the valence of the counter ion m, and M is a cation having a valence of from 1 to 3.

  3. Estimating the Variability of Substitution Rates

    Microsoft Academic Search

    Michael Bulmer

    1989-01-01

    Suppose that amino acid or nucleotide data are available for a homologous gene in several species which diverged from a common ancestor at about the same time and that substitution rates between all pairs of species are calculated, correcting as necessary for multiple substitutions and for back and parallel substitutions. The variances and covariances of these corrected substitution rates are

  4. FBE powder and coating tests evaluated

    SciTech Connect

    Coulson, K.E.W.; Temple, D.G.; Kehr, J.A.

    1987-08-10

    Properties of a fusion-bonded epoxy (FBE) external pipeline coating can be significantly affected by the conditions under which the FBE powder has been stored. Nova, An Alberta Corporation, and 3M Co. undertook a program of evaluating easily run tests to determine the suitability of FBE powder. These tests are less time consuming than the most commonly used series of tests which involve evaluating laboratory-coated specimens or testing rings taken from production-coated pipe. Detailed here is that study of powder aging, coating application, and laboratory testing of aged powders and the subsequent coatings obtained from these powders. The results indicate that gel-time test was the only powder-test method which was both speedy and accurate.

  5. Novel Approaches to Improve the Intrinsic Microbiological Safety of Powdered Infant Milk Formula

    PubMed Central

    Kent, Robert M.; Fitzgerald, Gerald F.; Hill, Colin; Stanton, Catherine; Ross, R. Paul

    2015-01-01

    Human milk is recognised as the best form of nutrition for infants. However; in instances where breast-feeding is not possible, unsuitable or inadequate, infant milk formulae are used as breast milk substitutes. These formulae are designed to provide infants with optimum nutrition for normal growth and development and are available in either powdered or liquid forms. Powdered infant formula is widely used for convenience and economic reasons. However; current manufacturing processes are not capable of producing a sterile powdered infant formula. Due to their immature immune systems and permeable gastro-intestinal tracts, infants can be more susceptible to infection via foodborne pathogenic bacteria than other age-groups. Consumption of powdered infant formula contaminated by pathogenic microbes can be a cause of serious illness. In this review paper, we discuss the current manufacturing practices present in the infant formula industry, the pathogens of greatest concern, Cronobacter and Salmonella and methods of improving the intrinsic safety of powdered infant formula via the addition of antimicrobials such as: bioactive peptides; organic acids; probiotics and prebiotics. PMID:25685987

  6. Novel approaches to improve the intrinsic microbiological safety of powdered infant milk formula.

    PubMed

    Kent, Robert M; Fitzgerald, Gerald F; Hill, Colin; Stanton, Catherine; Ross, R Paul

    2015-01-01

    Human milk is recognised as the best form of nutrition for infants. However; in instances where breast-feeding is not possible, unsuitable or inadequate, infant milk formulae are used as breast milk substitutes. These formulae are designed to provide infants with optimum nutrition for normal growth and development and are available in either powdered or liquid forms. Powdered infant formula is widely used for convenience and economic reasons. However; current manufacturing processes are not capable of producing a sterile powdered infant formula. Due to their immature immune systems and permeable gastro-intestinal tracts, infants can be more susceptible to infection via foodborne pathogenic bacteria than other age-groups. Consumption of powdered infant formula contaminated by pathogenic microbes can be a cause of serious illness. In this review paper, we discuss the current manufacturing practices present in the infant formula industry, the pathogens of greatest concern, Cronobacter and Salmonella and methods of improving the intrinsic safety of powdered infant formula via the addition of antimicrobials such as: bioactive peptides; organic acids; probiotics and prebiotics. PMID:25685987

  7. Foamed lightweight materials made from mixed scrap metal waste powder and sewage sludge ash.

    PubMed

    Wang, Kuen-Sheng; Chiou, Ing-Jia

    2004-10-01

    The porous properties and pozzolanic effects of sewage sludge ash (SSA) make it possible to produce lightweight materials. This study explored the effects of different metallic foaming agents, made from waste aluminium products, on the foaming behaviours and engineering characteristics, as well as the microstructure of sewage sludge ash foamed lightweight materials. The results indicated that aluminium powder and mixed scrap metal waste powder possessed similar chemical compositions. After proper pre-treatment, waste aluminium products proved to be ideal substitutes for metallic foaming agents. Increasing the amount of mixed scrap metal waste by 10-15% compared with aluminium powder would produce a similar foaming ratio and compressive strength. The reaction of the metallic foaming agents mainly produced pores larger than 10 microm, different from the hydration reaction of cement that produced pores smaller than 1 microm mostly. To meet the requirements of the lightweight materials characteristics and the compressive strength, the amount of SSA could be up to 60-80% of the total solids. An adequate amount of aluminium powder is 0.5-0.9% of the total solids. Increasing the fineness of the mixed scrap metal waste powder could effectively reduce the amount required and improve the foaming ratio. PMID:15560443

  8. Powder compaction properties of sodium starch glycolate disintegrants.

    PubMed

    Edge, S; Steele, D F; Staniforth, J N; Chen, A; Woodcock, P M

    2002-09-01

    The compaction behavior of three "as supplied" commercially available grades of sodium starch glycolate (SSG), Explotab, Primojel, and Vivastar P, was investigated at compression speeds of 0.17 and 30 mm/sec. The results suggested that the three "as supplied" materials exhibit different compression and compaction behavior. Primojel and Explotab exhibited similar compactibility, whereas Vivastar P produced compacts of poor integrity. This behavior was not mirrored in the compressibility of the powders, where Vivastar P and Explotab exhibited similar performance. The materials were studied using x-ray diffraction, scanning electron microscopy, Carr's compressibility index, and swelling volume. In terms of material characteristics, all the products exhibited similar swelling in water. Primojel and Explotab retained most of the crystallographic order from the parent potato starch and exhibited comparable particle surface topographies. Vivastar P contained the lowest moisture level. However, it is not clear if the poor compactibility of Vivastar P is due to differences in moisture content, the reduced surface topography, or subtle differences in the SSG polymer structures (substitution, cross-linking, and crystallinity). Overall, even though the three commercial grades of sodium starch glycolate are successfully used as disintegrants, they do exhibit differences in their "as supplied" powder mechanical properties: Primojel and Explotab exhibit similar compactibility, whereas Vivastar P is poorly compactable but exhibits similar compressibility to Explotab. These observations may have implications when formulating poorly compactable or moisture-sensitive drugs. PMID:12378967

  9. Process for the synthesis of iron powder

    DOEpatents

    Welbon, William W. (Belleair, FL)

    1983-01-01

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

  10. Magnetic properties of polymer bonded nanocrystalline powder

    Microsoft Academic Search

    P. Gramatyka; R. Nowosielski; P. Sakiewicz

    Purpose: The aim of this paper was to develop a dielectromagnetic based on nanocrystalline Fe73.5Cu1Nb3Si13.5B9 powder bonded with organo-silicon polymer and to investigate the powder particle size and content of polymer response of the magnetic properties. Design\\/methodology\\/approach: The dynamic magnetic properties at the frequency range from 50 Hz up to 100 kHz of nanocrystalline iron based powder cores were measured

  11. Volume 7. Copper base powder metallurgy

    Microsoft Academic Search

    Taubenblat

    1980-01-01

    This book is based on a series of lectures on copper and copper base P\\/M materials sponsored by the Metal Powder Industries Federation. It covers recent developments in the fields of copper powder metallurgy and offers a comprehensive survey of copper and copper-base P\\/M materials. It begins with a chapter on the production of copper and copper alloy powders followed

  12. Characterization of tribocharging properties of powder paint

    Microsoft Academic Search

    M. K. Mazumder; S. Banerjee; R. E. Ware; N. Kaya; C. C. Huang

    1992-01-01

    Simultaneous measurements of particle size and electrostatic charge was performed on charged powder paint and other powders in the particle size range from 1.0 to 65.0 ?m in diameter. An electrical single-particle aerodynamic relaxation time analyzer was used to measure electrostatic charge and aerodynamic size distributions on a single particle basis and in a noninvasive manner. The powders were triboelectrically

  13. Process for the synthesis of iron powder

    DOEpatents

    Not Available

    1982-03-06

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

  14. Process for the synthesis of iron powder

    DOEpatents

    Welbon, W.W.

    1983-11-08

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder. 2 figs.

  15. Characterization of tribocharging properties of powder paint

    Microsoft Academic Search

    M. K. Mazumder; S. Banerjee; R. E. Ware; C. Mu; N. Kaya; C. C. Huang

    1994-01-01

    The charge-to-mass ratio (q\\/m) of individual particles plays a vital role in the powder coating process. Simultaneous measurements of particle size and electrostatic charge were performed on triboelectrically charged powder paint and other powders in the particle size range 1.0 to 65.0 ?m in diameter. An electrical single particle aerodynamic relaxation time (ESPART) analyzer was used to measure electrostatic charge

  16. Production of nickel metal powder from a spent etching solution by solvent extraction and chemical reduction.

    PubMed

    Lee, Manseung

    2011-02-01

    Nickel metal powder with 99% purity was obtained from a spent FeCl3 etching solution by employing solvent extraction and chemical reduction. Iron and nickel was separated from the spent etching solution by solvent extraction with Alamine336. Iron in the spent etching solution was extracted into the organic phase, while nickel remained in the aqueous solution together with a small amount of iron. After eliminating iron in the aqueous solution by precipitation, nickel metal powder was obtained by chemical reduction with hydrazine at reaction temperature of 100 degrees C and at solution pH of 10.5. Chemical reduction at this specified condition led to nanosized spherical black nickel metal powder with 99% purity. PMID:21456251

  17. Dendritic microstructure in argon atomized superalloy powders

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Kumar, Mahundra

    1986-01-01

    The dendritic microstructure of atomized nickel base superalloy powders (Ni-20 pct Cr, NIMONIC-80A, ASTROALOY, and ZHS6-K) was studied. Prealloyed vacuum induction melted ingots were argon-atomized, the powders were cooled to room temperature, and various powder-size fractions were examined by optical metallography. Linear correlations were obtained for the powder size dependence of the secondary dendrite arm spacing, following the expected d-alpha (R) to the m power dependence on the particle size for all four superalloy compositions. However, the Ni-20 pct Cr alloy, which had much coarser arm spacing as compared to the other three alloys, had a much larger value of m.

  18. Preparation techniques for ceramic waste form powder

    SciTech Connect

    Hash, M.C.; Pereira, C.; Lewis, M.A. [and others

    1997-08-01

    The electrometallurgical treatment of spent nuclear fuels result in a chloride waste salt requiring geologic disposal. Argonne National Laboratory (ANL) is developing ceramic waste forms which can incorporate this waste. Currently, zeolite- or sodalite-glass composites are produced by hot isostatic pressing (HIP) techniques. Powder preparations include dehydration of the raw zeolite powders, hot blending of these zeolite powders and secondary additives. Various approaches are being pursued to achieve adequate mixing, and the resulting powders have been HIPed and characterized for leach resistance, phase equilibria, and physical integrity.

  19. Mössbauer study of substituted barium ferrite BaFe11- x-y Co0.5Ti0.5Ni x ZnyO19- r

    Microsoft Academic Search

    Yufang Zheng; Zhengfang Yu; Yuanzhi Shao; Shaohong Mo; Yongqiang Lin

    1994-01-01

    Substituted barium ferrite BaFe11- x-y Co0.5Ti0.5Ni x ZnyO19- r powders were prepared using a coprecipitation method and investigated by X-ray diffraction (XRD) and57Fe Mössbauer spectroscopy. The results show that the as-prepared magnetic powders possess the typical hexagonal structure and demonstrate both a good dispersibility and a narrow particle size distribution. The hyperfine fields for all sites decrease slightly as x

  20. Low cost photovoltaic modules based on dye sensitized nanocrystalline titanium dioxide and carbon powder

    Microsoft Academic Search

    Andreas Kay; Michael Grätzel

    1996-01-01

    A new type of photovoltaic module based on monolithically series connected dye sensitized photoelectrochemical cells is described. Each solar cell element consists of three porous layers on a transparent conducting substrate, namely a photoelectrode of dye sensitized nanocrystalline TiO2 (anatase), a spacer of electrically insulating, light reflecting particles of TiO2 (rutile), and a counterelectrode of graphite powder and carbon black.

  1. Two-nucleotide codon change in a hemoglobin polymorphism of the Celebes black ape ( Macaca nigra )

    Microsoft Academic Search

    Mitsuo Murata; Peter E. Thompson

    1976-01-01

    A hemoglobin polymorphism involving variant ß-chains was demonstrated in the Celebes black ape, Macaca nigra. Fingerprinting and amino acid analysis of the tryptic peptides from the two chain types have shown that they differ by a single amino acid substitution, between lysine and aspartic acid, which requires a two-nucleotide change in the corresponding codon. Another substitution in the same codon

  2. The comparison of powder characteristics and physicochemical, mechanical and biological properties between nanostructure ceramics of hydroxyapatite and fluoridated hydroxyapatite

    Microsoft Academic Search

    Hossein Eslami; Mehran Solati-Hashjin; Mohammadreza Tahriri

    2009-01-01

    In this study, several fluorine-substituted hydroxyapatite ceramics with the general chemical formula Ca5(PO4)3(OH)1?xFx (0?x?1), where x=0.0 (hydroxyapatite; HA), x=0.68 (fluorhydroxyapatite; FHA) and x=0.97 (fluorapatite; FA) were prepared. The powders were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infra-red (FTIR), X-ray diffraction (XRD), F-selective electrode, atomic absorption spectroscopy (AAS) and EDTA titration analyses. The powders were

  3. Powdered coal air dispersion nozzle

    SciTech Connect

    Kosek, T.P.; Steinhilper, E.A.

    1981-10-27

    An improved coal/air dispersion nozzle introduces fuel into the combustion chamber of a gas turbine engine as a finely atomized, dispersed spray for a uniform combustion. The nozzle has an inlet that receives finely powdered coal from a coal transport or coal/air fluidizer system and a scroll swirl generator is included within the nozzle to swirl a fluidized coal/air mixture supplied to the inlet of the nozzle. The scroll is in the form of a thin, flat metal sheet insert, twisted along its length, and configured to prevent build-up of coal particles within the nozzle prior to ejection from its outlet. Airblast air jets are included along the length of the nozzle body to assist in the discharge of the fluidized coal from the nozzle outlet and an angular pintle tip overlies the outlet to redirect coal/air mixture through a desired fluidized coal spray angle.

  4. Substituted decision making: elder guardianship.

    PubMed

    Leatherman, Martha E; Goethe, Katherine E

    2009-11-01

    The goal of this column is to help experienced clinicians navigate the judicial system when they are confronted with requests for capacity evaluations that involve guardianship (conservatorship). The interface between the growing elderly medical population and increasing requests for substituted decision making is becoming more complex. This column will help practicing psychiatrists understand the medical, legal, and societal factors involved in adult guardianship. Such understanding is necessary in order to effectively perform guardianship evaluations and adequately inform courts, patients, and families about the psychiatric diagnoses central to substituted decision making. PMID:19934723

  5. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...phenyl azo substituted benzenediazonium salt. 721.1555 Section 721.1555 ...phenyl azo substituted benzenediazonium salt. (a) Chemical substance and significant...phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject to...

  6. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...phenyl azo substituted benzenediazonium salt. 721.1555 Section 721.1555 ...phenyl azo substituted benzenediazonium salt. (a) Chemical substance and significant...phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject to...

  7. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...substituted phenyl) disulfonaphthyl azo, amine salt (generic). 721.2577 Section 721...substituted phenyl) disulfonaphthyl azo, amine salt (generic). Link to an amendment published...substituted phenyl) disulfonaphthyl azo, amine salt (PMNs P-00-0364 and...

  8. 40 CFR 721.9545 - Substituted phenyl azo substituted sulfocarbopolycle, sodium salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...azo substituted sulfocarbopolycle, sodium salt. 721.9545 Section 721.9545 ...azo substituted sulfocarbopolycle, sodium salt. (a) Chemical substance and significant...azo substituted sulfocarbopolycle, sodium salt (PMN P-96-1263) is subject to...

  9. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  10. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  11. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 2010-07-01 false Copper complex of (substituted sulfonaphthyl...Specific Chemical Substances § 721.2577 Copper complex of (substituted sulfonaphthyl...chemical substances identified generically as copper complex of (substituted...

  12. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...phenyl azo substituted benzenesulfonic acid copper compound (generic). 721.10126...triazine amino substituted benezenesulfonic acid reaction product with...

  13. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...phenyl azo substituted benzenediazonium salt. 721.1555 Section 721.1555 ...phenyl azo substituted benzenediazonium salt. (a) Chemical substance and significant...phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject to...

  14. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Copper complex of (substituted sulfonaphthyl...Specific Chemical Substances § 721.2577 Copper complex of (substituted sulfonaphthyl...chemical substances identified generically as copper complex of (substituted...

  15. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Copper complex of (substituted sulfonaphthyl...Specific Chemical Substances § 721.2577 Copper complex of (substituted sulfonaphthyl...chemical substances identified generically as copper complex of (substituted...

  16. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Copper complex of (substituted sulfonaphthyl...Specific Chemical Substances § 721.2577 Copper complex of (substituted sulfonaphthyl...chemical substances identified generically as copper complex of (substituted...

  17. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Butyl acrylate, polymer with substituted methyl styrene, methyl...Substances § 721.6920 Butyl acrylate, polymer with substituted methyl styrene, methyl...substance identified as butyl acrylate, polymer with substituted methyl styrene,...

  18. Emerging drugs of abuse: current perspectives on substituted cathinones

    PubMed Central

    Paillet-Loilier, Magalie; Cesbron, Alexandre; Le Boisselier, Reynald; Bourgine, Joanna; Debruyne, Danièle

    2014-01-01

    Substituted cathinones are synthetic analogs of cathinone that can be considered as derivatives of phenethylamines with a beta-keto group on the side chain. They appeared in the recreational drug market in the mid-2000s and now represent a large class of new popular drugs of abuse. Initially considered as legal highs, their legal status is variable by country and is rapidly changing, with government institutions encouraging their control. Some cathinones (such as diethylpropion or pyrovalerone) have been used in a medical setting and bupropion is actually indicated for smoking cessation. Substituted cathinones are widely available from internet websites, retail shops, and street dealers. They can be sold under chemical, evocative or generic names, making their identification difficult. Fortunately, analytical methods have been developed in recent years to solve this problem. Available as powders, substituted cathinones are self-administered by snorting, oral injestion, or intravenous injection. They act as central nervous system stimulants by causing the release of catecholamines (dopamine, noradrenaline, and serotonin) and blocking their reuptake in the central and peripheral nervous system. They may also decrease dopamine and serotonin transporter function as nonselective substrates or potent blockers and may inhibit monoamine oxidase effects. Nevertheless, considerable differences have been found in the potencies of the different substituted cathinones in vitro. Desired effects reported by users include increased energy, empathy, and improved libido. Cardiovascular (tachycardia, hypertension) and psychiatric/neurological signs/symptoms (agitation, seizures, paranoia, and hallucinations) are the most common adverse effects reported. Severe toxicity signs compatible with excessive serotonin activity, such as hyperthermia, metabolic acidosis, and prolonged rhabdomyolysis, have also been observed. Reinforcing potential observed in animals predicts a high potential for addiction and abuse in users. In case of overdose, no specific antidote exists and no curative treatment has been approved by health authorities. Therefore, management of acute toxic effects is mainly extrapolated from experience with cocaine/amphetamines. PMID:24966713

  19. FBE powder and coating tests evaluated

    Microsoft Academic Search

    K. E. W. Coulson; D. G. Temple; J. A. Kehr

    1987-01-01

    Properties of a fusion-bonded epoxy (FBE) external pipeline coating can be significantly affected by the conditions under which the FBE powder has been stored. Nova, An Alberta Corporation, and 3M Co. undertook a program of evaluating easily run tests to determine the suitability of FBE powder. These tests are less time consuming than the most commonly used series of tests

  20. Physical and dielectric properties of pharmaceutical powders

    Microsoft Academic Search

    C. M McLoughlin; W. A. M McMinn; T. R. A Magee

    2003-01-01

    The limited availability of published physical and dielectric property data for pharmaceutical powders hinders the design of processing systems, particularly dryers. In this study, the physical properties (solubility and boiling point) and dielectric properties, in terms of temperature rise, dielectric constant, and dielectric loss factor, of selected pharmaceutical powders were measured. The pharmaceutical actives, paracetamol and aspirin, and selected common

  1. Caking phenomena in amorphous food powders

    Microsoft Academic Search

    José M. Aguilera; José M. del Valle; Marcus Karel

    1995-01-01

    Caking of free-flowing powders during storage is a deleterious phenomenon that is ubiquitous in the feed, fertilizer and pharmaceutical industries, and of economical importance for low-moisture foods. Among other subjects related to caking of amorphous powders, the following aspects are reviewed in this article: (1) physical and morphological changes, and quantitative procedures to assess caking; (2) proposed mechanisms of caking

  2. Tungsten Powder Jet Update Ottone Caretta

    E-print Network

    McDonald, Kirk

    Tungsten Powder Jet Update Ottone Caretta STFC Rutherford Appleton Laboratory, UK 2nd Princeton-Oxford High Power Target Meeting 6-7 November-2008 #12;Tungsten Powder Jet 2cm Thank you to EIP at RAL tungsten pellets Helium cooling #12;NF-IDS and EUROnu Targets Work Program (30 months) NF-IDS primarily

  3. Slip casting and nitridation of silicon powder

    NASA Technical Reports Server (NTRS)

    Seiko, Y.

    1985-01-01

    Powdered Silicon was slip-cast with a CaSO4 x 0.5H2O mold and nitrided in a N atm. containing 0 or 5 vol. % H at 1000 to 1420 deg. To remove the castings, the modeling faces were coated successively with an aq. salt soap and powdered cellulose containing Na alginate, and thus prevented the sticking problem.

  4. Tribocharging of Three-Component Powder Mixtures

    Microsoft Academic Search

    J. H. Anderson; Elizabeth Fox

    1995-01-01

    Adhesion of charged toner particles used in electrophotography is dominated by electrostatic forces. In this paper we discuss a model which describes the process by which toner particles acquire their electrostatic charge, tribocharging.In previous papers, we have presented a model of tribocharging of two-component mixtures of powders based on the assumptions that: 1. The surface of each powder is populated

  5. Derivatised carbon powder electrodes: reagentless pH sensors.

    PubMed

    Leventis, Henry C; Streeter, Ian; Wildgoose, Gregory G; Lawrence, Nathan S; Jiang, Li; Jones, Timothy G J; Compton, Richard G

    2004-07-01

    In this report, we derivatise carbon powder with anthracene, azobenzene, diphenylamine, 9,10-diphenylanthracene, methylene blue, 3-nitrofluoranthene, 6-nitrochrysene, 9-nitroanthracene, 9,10-phenanthraquinone (PAQ), thionin, and fast black K (2,5-dimethoxy-4-[(4-nitrophenyl)azo]benzenediazonium chloride) and separately immobilise the resulting material onto a bppg electrode. We use cyclic voltammetry (CV) to demonstrate that the observed voltammetric response for each derivatised carbon is consistent with that of an immobilised species. Further, we use CV and square wave voltammetry (SWV) to investigate the effect of pH on the peak potentials of each compound studied over the range pH 1-12 and at elevated temperatures up to 70 degrees C in order to demonstrate the versatility of derivatised carbon electrodes as reagentless pH sensors. PMID:18969532

  6. Wet powder seal for gas containment

    DOEpatents

    Stang, Louis G. (Sayville, NY)

    1982-01-01

    A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

  7. Effect of detergent on powder triboelectrification.

    PubMed

    Murtomaa, Matti; Ojanen, Kalle; Laine, Ensio; Poutanen, Jutta

    2002-12-01

    Triboelectrification of pharmaceutical powders during processing and manufacture may cause adhesion/cohesion effects, reduce fill and dose uniformity, affect powder flow and packing behaviour and even obstruct the manufacturing of the product. This paper presents the results of an experimental study on the triboelectrification of microcrystalline cellulose in contact with stainless steel pipes washed with several different detergents. Detergents and their concentrations were chosen to be similar to typical industrial manufacturing stages. The adhesion of powder to the surface had a considerable effect on the triboelectrification process. Therefore, polystyrene spheres were also charged in a similar way and the results were compared with the powder charging results. The results clearly indicate that detergent contamination on the pipe surface has a considerable effect on the generated charge. The detergents and powders used could be arranged in a triboelectric series with only one exception. PMID:12453608

  8. Black Carbon

    NSDL National Science Digital Library

    NBC Learn

    2010-10-07

    Black carbon, composed of tiny particles of soot, is produced whenever organic substances like fossil fuels, firewood or coal is incompletely burned. These particles are polluting the air and causing serious health and environmental concerns for people around the world. "Changing Planet" is produced in partnership with the National Science Foundation.

  9. Black Flies

    NSDL National Science Digital Library

    0000-00-00

    Information about the common annoyance pest the Black Fly. The flies life cycle and control strategy are covered. While the information is specific to Los Angeles California, the same strategies are effective elsewhere. Personal protection information is also offered and is universally effective.

  10. Black Hills

    Atmospheric Science Data Center

    2014-05-15

    ... of northeastern Wyoming, the Black Hills, and western South Dakota remain in the midst of a severe drought. This set of images and maps ... and every 9 days views the entire globe between 82° north and 82° south latitude. This image area covers about 243 kilometers ...

  11. Counseling Blacks

    ERIC Educational Resources Information Center

    Vontress, Clemmont E.

    1970-01-01

    Blacks have developed unique environmental perceptions, values, and attitudes, making it difficult for counselors to establish and maintain positive rapport. This article examines attitudinal ingredients posited by Carl Rogers for relevance to this problem, and suggests in-service training to help counselors and other professionals relate…

  12. Solving Substitution Ciphers Sam Hasinoff

    E-print Network

    Toronto, University of

    Doyle's short story "The Adventure of the Dancing Men" (1903), the pro- tagonist Sherlock Holmes solves NOT READ BOOKS HAS NO ADVANTAGE OVER THE MAN THAT CAN NOT READ THEM. --MARK TWAIN ciphertext AIQ UZT EIV of short substitution ciphers (Cryptoquotes). The system operates using an -gram model of English

  13. Substitute Teaching: Sink or Swim.

    ERIC Educational Resources Information Center

    Duebber, Diane

    2000-01-01

    Advises new substitute teachers to be prepared, tote emergency activity folders, dress professionally (but wear flamingo earrings), be early, figure out the game plan, communicate expectations to students, enforce consequences, have a gimmick to reward cooperation, relish the teachable moment, leave the room tidy, and believe in themselves. (MLH)

  14. Skin Substitutes and Wound Healing

    Microsoft Academic Search

    F. A. Auger; D. Lacroix; L. Germain

    2009-01-01

    Medical science has vastly improved on the means and methods available for the treatment of wounds in the clinic. The production and use of various types of skin substitutes has led to dramatic improvements in the odds of survival for severely burned patients, but they have also shown promise for many other applications, including cases involving chronic wounds that are

  15. Improved critical current density in ex situ processed carbon-substituted MgB2 tapes by Mg addition

    NASA Astrophysics Data System (ADS)

    Fujii, H.; Ozawa, K.; Kitaguchi, H.

    2012-06-01

    We have studied the effect of planetary ball-milling of filling powder with mineral oil on the carbon substitution and the critical current density (Jc) of Fe-sheathed MgB2 tapes fabricated through an ex situ process in a powder-in-tube (PIT) technique. Although tapes using powder with oil treatment show weak coupling, the Jc properties of those tapes are enhanced due to carbon substitution for boron. The ball-milling treatment with the oil on the filling powder with Mg addition further enhances the Jc property of tapes. The Jc values of the tapes reach about 9 kA cm-2 at 4.2 K and 10 T. The ball-milling produces a fresh clean surface by the grinding of large grains with a damaged surface and promotes a carbon substitution reaction. Mg addition compensates for the deviation in composition which occurs in the reaction. Some of the boron which is released from MgB2 at the reaction can act as an obstacle to the supercurrent path. The additional Mg consumes the boron at the formation of MgB2 and improves the grain coupling.

  16. 21 CFR 520.1696b - Penicillin G powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Penicillin G powder. 520.1696b Section...NEW ANIMAL DRUGS § 520.1696b Penicillin G powder. (a) Specifications. Each gram of powder contains penicillin G potassium equivalent to...

  17. 21 CFR 520.1696b - Penicillin G powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Penicillin G powder. 520.1696b Section...NEW ANIMAL DRUGS § 520.1696b Penicillin G powder. (a) Specifications. Each gram of powder contains penicillin G potassium equivalent to...

  18. 47 CFR 76.110 - Substitutions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Network Non-duplication Protection, Syndicated Exclusivity and Sports Blackout § 76.110 Substitutions. Whenever, pursuant...such community unit may, consistent with these rules and the sports blackout rules at § 76.111, substitute a program from...

  19. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Benzenesulfonic acid, amino substituted phenylazo-. 721... § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. ...generically as a benzenesulfonic acid, amino substituted phenylazo-...

  20. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Benzenesulfonic acid, amino substituted phenylazo-. 721... § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. ...generically as a benzenesulfonic acid, amino substituted phenylazo-...

  1. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Benzenesulfonic acid, amino substituted phenylazo-. 721... § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. ...generically as a benzenesulfonic acid, amino substituted phenylazo-...

  2. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Benzenesulfonic acid, amino substituted phenylazo-. 721... § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. ...generically as a benzenesulfonic acid, amino substituted phenylazo-...

  3. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Benzenesulfonic acid, amino substituted phenylazo-. 721... § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. ...generically as a benzenesulfonic acid, amino substituted phenylazo-...

  4. Preparation and characterization of uranyl oxalate powders

    NASA Astrophysics Data System (ADS)

    Tel, H.; Bülbül, M.; Eral, M.; Alta?, Y.

    1999-10-01

    Uranyl oxalate powders are prepared by adding 0.5 M oxalic acid solution to the uranyl nitrate (UNH) solutions purified with TBP extraction from dissolution of the Canada originated U 3O 8 commercial concentrate. Uranyl oxalate powders are identified by chemical analysis, TGA/DTG analysis, IR analysis and by single-crystal X-ray diffraction. The effects of the precipitation conditions on the powder properties are determined. A broad particle size distribution is obtained for all precipitation variants. These powders including very fine particles are difficult to filter and are not free flowing. The reactor and mixing type have a considerable effect on the powder properties of the uranyl oxalate powders. It was possible to ameliorate the filtration and the flowability to a certain degree using a conical air agitated reactor. The flowability of these powders is 0.4 g/s with a specific surface area 6.64 m 2/g and an average particle size of 11 ?m.

  5. Dry powder formulation of simvastatin.

    PubMed

    Tulbah, Alaa S; Ong, Hui Xin; Morgan, Lucy; Colombo, Paolo; Young, Paul M; Traini, Daniela

    2014-09-22

    Objectives: This study focuses on the development of a dry powder inhaler (DPI) formulation of simvastatin (SV), and the effects of SV on the respiratory epithelium. Methods: Micronised SV samples were prepared by dry jet-milling. The long-term chemical stability and physicochemical properties of the formulations were characterised in terms of particles size, morphology, thermal and moisture responses. Furthermore, in vitro aerosol depositions were performed. The formulation was evaluated for cell viability and its effect on cilia beat activity, using ciliated nasal epithelial cells in vitro. The formulation transport across an established air interface Calu-3 bronchial epithelial cells and its ability to reduce mucus secretion was also investigated. Results: The particle size of the SV formulation and its aerosol performance were appropriate for inhalation therapy. Moreover, the formulation was found to be non-toxic to pulmonary epithelia cells and cilia beat activity up to a concentration of 10(-6) M. Transport studies revealed that SV has the ability to penetrate into airway epithelial cells and is converted into its active SV hydroxy acid metabolite. Single dose of SV DPI also decreased mucus production after 4 days of dosing. Conclusion: This therapy could potentially be used for the local treatment of diseases like chronic obstructive pulmonary disease, cystic fibrosis, and bronchiectasis given its anti-inflammatory effects and ability to reduce mucus production. PMID:25244365

  6. Baby powder use in infant skin care. Parental knowledge and determinants of powder usage.

    PubMed

    Hayden, G F; Sproul, G T

    1984-03-01

    One hundred parents of infants aged 2 weeks to 6 months were surveyed at the time of routine well-child visits to assess parental knowledge about baby powder and to determine whether hospital policy of providing a free powder sample to newly delivered mothers was unwittingly promoting powder usage. Most parents (69%) reported regular baby powder use as part of routine infant skin care. Powder-users were significantly more likely than nonusers to attribute to baby powder the ability to kill bacteria and yeast and to prevent diaper rash (p less than 0.01). Even among nonusers, fewer than half were aware that aspiration/ingestion of baby powder was a potential health hazard. Almost all parents reported receiving a free sample of baby powder while in the hospital as part of a complimentary gift pack provided by the manufacturers. Most powder-users were currently using a brand they had received as a sample, and eight parents cited the receipt of a sample as the major determinant for selecting a particular brand of powder. The short- and long-term effects of distributing sample packs to newly delivered parents deserve further study. PMID:6697622

  7. Black Europeans

    NSDL National Science Digital Library

    The British Library has been producing quality online features for close to a decade now, and this latest offering is worth a close look. This particular feature offers some insights and commentary on five prominent black Europeans. It may even come as a surprise to some visitors that several of the individuals profiled were black, such as Alexandre Dumas, the celebrated author of The Three Musketeers. These profiles are supplemented with essays by Dr. Mike Phillips, a writer, scholar, and journalist. The essays are accompanied by a series of images, including engravings, portraits, and illustrations. Visitors may also want to view and print out extended versions of Phillipsâ?? essays, which are available here in the pdf format.

  8. Powder metallurgy design manual, 2nd edition

    SciTech Connect

    NONE

    1995-12-31

    This book is the most concise and comprehensive book of its kind on powder metallurgy (P/M) technology for both component design and application. Completely updated from the previous edition, this valuable reference gives an entirely new coverage on metal injection molding (MIM) and powder forging (P/F) with applicable case histories. There is revised information on P/M compared with other technologies, prototyping, and properties and characteristics of alloys, powders and P/M materials. In addition there`s expanded data on sintering including liquid phase processing and hardening.

  9. Production of powders of maraging steels

    SciTech Connect

    Agbalyan, S.G.; Badeyan, B.F.; Samvelyan, R.G. [Armenian State Engineering Institute, Erevan (Armenia)] [and others

    1995-03-01

    Maraging steels have attracted an increasing amount of attention in recent years due to their favorable combination of high strength and ductility properties, resistance to heat, cold, and brittle fracture, and dimensional stability during heat treatment. Unfortunately, maraging steels in powder form have not yet been studied to the extent merited. The main problem is that such powders are obtained by mechanical mixing of the components - an operation that does not ensure homogeneity the alloy after sintering. The present study was undertaken with the goal of obtaining powdered maraging steels by synthesizing and reducing complex oxides.

  10. Synthesis of nanocrystalline tungsten carbide (WC) powder

    NASA Astrophysics Data System (ADS)

    Singla, Gourav; Singh, K.; Pandey, O. P.

    2013-06-01

    Nanocrystalline tungsten carbide (WC) has been obtained from bulk WO3 by in situ reduction and carbonization reactions at low temperature (˜ 600 °C) by taking Mg as reductant and acetone C3H6O as carbon source. It was aimed to elucidate carburization behavior of WO3 powder and to establish optimal conditions for the synthesis of nanocrystalline WC. The role of reaction time on the synthesis of WC has been investigated and discussed. The synthesized powders were characterized by X-ray powder diffraction, differential thermal analyzer (DTA), thermo gravimetric analysis (TGA).

  11. Ethynyl and substituted ethynyl-terminated polysulfones

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M. (inventor)

    1984-01-01

    Ethynyl and substituted ethynyl-terminated polysulfones and a process for preparing the same are disclosed. These polysulfones are thermally cured to induce cross-linking and chain extension, producing a polymer system with improved solvent resistance and use temperature. Also disclosed are substituted 4-ethynylbenzoyl chlorides as precursors to the substituted ethynyl-terminated polysulfones and a process for preparing the same.

  12. Ethynyl and substituted ethynyl-terminated polysulfones

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M. (inventor)

    1986-01-01

    Ethynyl and substituted ethynyl-terminated polysulfones and their synthesis are disclosed. These polysulfones are thermally cured to induce cross-linking and chain extension, producing a polymer system with improved solvent resistance and use temperatures. Also disclosed are substituted 4-ethynylbenzoyl chlorides as precursors to the substituted ethynyl-terminated polysulfones and a process for preparing the same.

  13. Pitfalls in Designing Substitution Boxes Jennifer Seberry

    E-print Network

    Seberry, Jennifer

    Pitfalls in Designing Substitution Boxes Jennifer Seberry Xian-Mo Zhang Yuliang Zheng Department encryption algorithms. An eminent problem that researchers are facing is to design S-boxes or substitution prone to the di erential cryptanalytic attack. Key Words substitution boxes (S-boxes), permutations, di

  14. Expectations and Experiences of Substitute Teachers

    ERIC Educational Resources Information Center

    Duggleby, Patricia; Badali, Sal

    2007-01-01

    This article explores the expectations of support for and the experiences of substitute teachers in an urban school division in Saskatchewan. Data were collected in semistructured interviews with seven substitute teachers. The purpose of the study was to explore how substitute teachers frame their professional experiences and construct their roles…

  15. Efficient Cryptanalysis of Homophonic Substitution Amrapali Dhavare

    E-print Network

    Stamp, Mark

    technique to the "Zodiac 340" cipher, which is an unsolved message created by the infamous Zodiac killer. Keywords: homophonic substitution cipher, simple substitution cipher, hill climb, heuristic search, Zodiac. Our motivation for considering homophonic substitution ciphers is the unsolved "Zodiac 340," which

  16. Substitutes for School Nurses in Illinois

    ERIC Educational Resources Information Center

    Vollinger, Linda Jeno; Bergren, Martha Dewey; Belmonte-Mann, Frances

    2011-01-01

    The purpose of this descriptive study was to explore utilization of nurse substitutes in the school setting in Illinois. The literature described personnel who staff the school health office in the absence of the school nurse and the barriers to obtaining nurse substitutes. There were no empirical studies conducted on school nurse substitutes in…

  17. Investigation of the structural and microwave dielectric properties of mechanically alloyed Fe40Co60 powders

    NASA Astrophysics Data System (ADS)

    Otmane, F.; Bergheul, S.; Triaa, S.; Azzaz, M.

    2014-08-01

    Fe40Co60 powders were produced by mechanical Alloying (MA) route. Structural and microwave dielectric properties were investigated. Discussion of obtained results is conducted according to milling time. X-Ray powder Diffraction (XRD) shows that disordered ? (Fe40Co60) solid solution of substitution with body centered cubic (bcc) lattice is formed after 2h milling. Halder Wagner analysis reveals that least grain size of 15.59 nm and residual strain up to 0.8% are reached after 60h milling. The evolution of the Voigtian mixing factors according to milling progression confirms that structural properties are governed by residual strain accumulated during high- energy mechanical alloying (Gaussian profiles). Scanning Electron Microscopy (SEM) indicates that obtained powders adopt flattened angular shapes with high surface area. Microwave measurements are undertaken on bulk samples. High values of the dielectric permittivity depicting the conductive behavior of Fe-Co powders are measured. Dielectric permittivity spectra according to milling time shift towards higher values. Enhancement of the dielectric properties is related to the developed structure after milling.

  18. Synthesis and characterization of hydroxyapatite, fluoride-substituted hydroxyapatite and fluorapatite.

    PubMed

    Wei, M; Evans, J H; Bostrom, T; Grøndahl, L

    2003-04-01

    Powders of hydroxyapatite (HA), partially fluoride-substituted hydroxyapatite (fHA), and fluorapatite (FA) were synthesized in house using optimum methods to achieve relatively pure powders. These powders were assessed by the commonly used bulk techniques of X-ray diffraction (XRD), Fourier transform infra-red (FTIR) and FT-Raman spectroscopies, inductively coupled plasma atomic emission spectroscopy (ICP-AES), and F-selective electrode. In addition, the current study has employed transmission electron microscopy (TEM), involving morphological observation, electron diffraction and energy-dispersive X-ray spectrometry (EDX), as an effective analytical technique to evaluate the powders at a microscopic level. The HA and fHA particles were elongated platelets about 20 x 60 nm in size, while FA particles were over twice this size. Calcination of the HA and fHA powders at 1000 degrees C for 1 h resulted in increased grain size and crystallinity. The calcined fHA material appeared to possess a crystal structure intermediate between HA and FA, as evidenced by the (3 0 0) peak shift in XRD, as well as by the position of the hydroxyl bands in the FTIR spectra. This result was consistent with electron diffraction of individual particles. Small levels of impurities in some of the powders were identified by EDX and electron diffraction, and the carbonate content was detected by FTIR. The use of TEM in conjunction with the bulk techniques has allowed a more thorough assessment of the apatites, and has enabled the constituents in these closely related apatite powders to be identified. PMID:15348455

  19. A new approach to assess the chemical composition of powder deposits damaging the stone surfaces of historical monuments.

    PubMed

    Fermo, Paola; Turrion, Raquel Gonzalez; Rosa, Mario; Omegna, Alessandra

    2014-11-20

    The issue of conservation of the monumental heritage worldwide is mainly related to atmospheric pollution that causes the degradation of stone surfaces. The powder deposits present on the stone monuments reflect the composition of the aerosol particulate matter (PM) to which the surfaces are exposed, so the chemical characterization of the outermost damaged layers is necessary in order to adopt mitigation measurements to reduce PM emissions. In the present paper, a new analytical approach is proposed to investigate the chemical composition of powder deposits present on Angera stone, a dolomitic rock used in the Richini courtyard, a masterpiece of Lombard Baroque and placed in Milan. Inorganic and organic components present in these deposits have been analyzed by IC (ion chromatography) and a new approach mainly bases on thermal analyses, respectively. Gypsum is the main inorganic constituent indicating a composition similar to that of black crusts, hard black patina covering the degraded building surfaces. Ammonium nitrate present in the powder is able to react with the stone substrate to form magnesium nitrate which can migrate into the porous stone. The carbonaceous fraction powder deposits (i.e. OC?=?Organic Carbon and EC?=?Elemental Carbon) have been quantified by a new simple thermal approach based on carbon hydrogen nitrogen (CHN) analysis. The presence of high concentration of EC confirms that the powder deposits are evolving to black crust. Low values of water-soluble organic carbon (WSOC, determined by total organic carbon-TOC), with respect to what is normally found in PM, may indicate a migration process of organic substances into the stone with a worsening of the conservation conditions. The presence of heavy metals of anthropogenic origin and acting as catalysts in the black crust formation process has been highlighted by SEM-EDS (electron microscopy coupled with an energy dispersive spectrometer) as well. PMID:25408080

  20. Assessment of asbestos insulation substitutes

    SciTech Connect

    Fourroux, J.D.; Frank, R.L. Jr.; Newberry, T.W. Jr. (Tennessee Valley Authority, Chattanooga, TN (USA))

    1990-03-01

    A state-of-the-art study of asbestos insulation alternatives has been conducted to identify the best substitute material for steam lines in power plants. A survey of utilities across the nation showed that calcium silicate is the most commonly employed material today, followed by mineral wool, fiberglass, and ceramic fibers. However, the calcium silicate was found to be dusty and to become brittle once exposed to elevated temperatures. Although it is asbestos-free, studies on its carcinogenicity are incomplete. Characteristic data on existing substitute materials is compiled and an optimum choice of insulation combination is configured. Potential cost savings of using this combination is evaluated for a major utility. A PC-based computer program is developed to assist utility personnel in selecting the proper insulation materials for steam lines. 31 refs., 8 figs.

  1. Resonant photodissociation in substituted benzenes

    NASA Astrophysics Data System (ADS)

    Scarborough, Tim; McAcy, Collin; Foote, David; Uiterwaal, Cornelis

    2011-06-01

    Cyclic aromatic molecules are abundant in organic chemistry, with a wide variety of applications, including pharmacology, pollution studies and genetic research. Among the simplest of these molecules is benzene (C6H6), with many relevant molecules being benzene-like with a single atomic substitution. In such a substitution, the substituent determines a characteristic perturbation of the electronic structure of the molecule. We discuss the substitution of halogens into the ring (C6H5X), and its effects on the dynamics of ionization and dissociation of the molecule without the focal volume effect [1]. In particular, using 800-nm, 50-fs laser pulses, we present results in the dissociation of fluorobenzene, chlorobenzene, bromobenzene and iodobenzene into the phenyl ring (C6H5) and the atomic halogen, and the subsequent ionization of these fragments. The impact of the ``heavy atom effect'' on a ^1(?,?*) -> ^3(n,?*) singlet-triplet intersystem crossing will be emphasized. Currently under investigation is whether such a dissociation can be treated as an effective source of the neutral substituent.[4pt] [1] J. Strohaber and C. Uiterwaal, Phys. Rev. Lett. 100 023002 (2008).

  2. Iridium-Catalyzed Allylic Substitution

    NASA Astrophysics Data System (ADS)

    Hartwig, John F.; Pouy, Mark J.

    Iridium-catalyzed asymmetric allylic substitution has become a valuable method to prepare products from the addition of nucleophiles at the more substituted carbon of an allyl unit. The most active and selective catalysts contain a phosphoramidite ligand possessing at least one arylethyl substituent on the nitrogen atom of the ligand. In these systems, the active catalyst is generated by a base-induced cyclometalation at the methyl group of this substituent to generate an iridium metalacycle bound by the COD ligand of the [Ir(COD)Cl]2 precursor and one additional labile dative ligand. Such complexes catalyze the reactions of linear allylic esters with alkylamines, arylamines, phenols, alcohols, imides, carbamates, ammonia, enolates and enolate equivalents, as well as typical stabilized carbon nucleophiles generated from malonates and cyanoesters. Iridium catalysts for enantioselective allylic substitution have also been generated from phosphorus ligands with substituents bound by heteroatoms, and an account of the studies of such systems, along with a description of the development of iridium catalysts is included.

  3. Contemporary Black Theatre.

    ERIC Educational Resources Information Center

    Thomas, Pearl

    The distinguishable black theatre in America, mirroring a distinguishable black experience, is an artistic product which demands audience involvement. Both the Afro-American oral tradition and the art of gesture are integral aspects of black theatre. In addition, the tragedy found black theatre is not tragedy in the classic sense, as blacks feel…

  4. Black Women and Feminism

    Microsoft Academic Search

    Clyde Wilcox

    1990-01-01

    Little research to date has examined the attitudes of black women toward feminism, primarily because few national surveys contain sufficient numbers of black women to take meaningful generalizations. Using data from a national survey of blacks in 1980, this study explores the levels and determinants of feminism among black women. The results show strong support for feminism among black women,

  5. Smoking Cessation among Blacks.

    ERIC Educational Resources Information Center

    Stotts, R. Craig; And Others

    1991-01-01

    Lung cancer is a serious health problem among blacks, with a mortality rate of 119 per 100,000 black males, compared to 81 per 100,000 for white males. Smoking cessation efforts are most successful when tailored to the black community, using black community networks and broadcast media for black audiences. (SLD)

  6. Applications of high-temperature powder metal aluminum alloys to small gas turbines

    NASA Technical Reports Server (NTRS)

    Millan, P. P., Jr.

    1982-01-01

    A program aimed at the development of advanced powder-metallurgy (PM) aluminum alloys for high-temperature applications up to 650 F using the concepts of rapid solidification and mechanical alloying is discussed. In particular, application of rapidly solidified PM aluminum alloys to centrifugal compressor impellers, currently used in auxiliary power units for both military and commercial aircraft and potentially for advanced automotive gas turbine engines, is examined. It is shown that substitution of high-temperature aluminum for titanium alloy impellers operating in the 360-650 F range provides significant savings in material and machining costs and results in reduced component weight, and consequently, reduced rotating group inertia requirements.

  7. Cation distribution in ZnFe 2O 4 fine particles studied by neutron powder diffraction

    NASA Astrophysics Data System (ADS)

    Kamiyama, T.; Haneda, K.; Sato, T.; Ikeda, S.; Asano, H.

    1992-02-01

    The structures of ZnFe 2O 4 fine particles prepared by a coprecipitation method have been studied by time-of-flight neutron powder diffraction at room temperature. The occupancy of Fe 3+ ion at a tetrahedral A-site is 0.108 for sample A (crystallite size 960 Å) and 0.142 for sample B (290 Å), which indicates that the cation substitution increases with decreasing particle size. The large magnetization in ZnFe 2O 4 fine particles compared with bulk materials is ascribable to a strong coupling between Fe 3+ ions at A- and B- sites due to the A-B interaction.

  8. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive copper powder shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

  9. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive bronze powder shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

  10. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive copper powder shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

  11. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...starch (including food starch-modified as prescribed in § 172.892 of this chapter). (5) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of the anticaking ingredients specified in...

  12. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...starch (including food starch-modified as prescribed in § 172.892 of this chapter). (5) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of the anticaking ingredients specified in...

  13. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...starch (including food starch-modified as prescribed in § 172.892 of this chapter). (5) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of the anticaking ingredients specified in...

  14. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...starch (including food starch-modified as prescribed in § 172.892 of this chapter). (5) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of the anticaking ingredients specified in...

  15. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...starch (including food starch-modified as prescribed in § 172.892 of this chapter). (5) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of the anticaking ingredients specified in...

  16. Dry-powder inhalers in acute asthma.

    PubMed

    Selroos, Olof

    2014-01-01

    An updated literature search was performed to evaluate the efficacy of rapid-acting ?2-agonists delivered via dry powder inhalers in the treatment of moderate-to-severe acute asthma. Databases were searched from 1985 up to December 2012. A total of 23 randomized, double-blind or open clinical studies in acute asthma comparing the efficacy of a dry powder inhaler with a pressurized metered-dose inhaler or a nebulizer, and performed under controlled hospital conditions, were identified. This review found that administration of ?2-agonist bronchodilators via dry powder inhalers (formoterol, salbutamol, terbutaline and budesonide/formoterol) was effective during severe asthma worsening and acute asthma attacks, and was as effective as established therapies with a pressurized metered-dose inhaler with or without a spacer, or nebulization. These results ensure that patients can rely upon dry powder inhalers equally well as other inhaler devices during episodes of asthma worsening. PMID:24341818

  17. An application of powder metallurgy to dentistry.

    PubMed

    Oda, Y; Ueno, S; Kudoh, Y

    1995-11-01

    Generally, the dental casting method is used to fabricate dental prostheses made with metal. The method of fabricating dental prostheses from sintered titanium alloy has certain advantages: the elimination of casting defects, a sintering temperature that is lower than the melting point, and a shorter processing time. By examining (1) the properties of green, sintered compacts of titanium powder, (2) the effects of adding aluminum powder on the properties of green, sintered compacts of Ti-Al compound, and (3) the effects of adding copper powder on the properties of green, sintered compacts of Ti-Al-Cu compound, the authors developed a sintered titanium alloy on a trial basis. Because the properties satisfied the requirements of dental restorations, a powder metallurgical method of making dental restorations from this sintered titanium alloy was devised. Applications of such sintered titanium alloys for the metal coping of metal-ceramic crowns and denture base plates were discussed. PMID:8689755

  18. Screening and classification of ceramic powders

    NASA Technical Reports Server (NTRS)

    Miwa, S.

    1983-01-01

    A summary is given of the classification technology of ceramic powders. Advantages and disadvantages of the wet and dry screening and classification methods are discussed. Improvements of wind force screening devices are described.

  19. LaRC dry powder towpreg process

    NASA Technical Reports Server (NTRS)

    Marchello, Joseph M.; Baucom, Robert M.

    1991-01-01

    The dry powder towpreg process overcomes many of the difficulties associated with melt, solution and slurry prepregging of advanced composite materials. In the process, fluidized powder is deposited on spread tow bundles and melted on the fibers by radiant heating to adhere the polymer to the fiber. Bench scale design and operating data have been correlated for use in process scale up to commercial operation. Powdered towpreg has been woven and molded into preform material of good quality. Cost estimates suggest that processing costs are comparable to those of conventional hot melt prepreg. In the future, from a part fabrication point of view, powder coated prepreg tape, woven broad goods and woven and braided preforms may be considered as options to similar materials made by other methods.

  20. Making Pure Fine-Grained Inorganic Powder

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1985-01-01

    Sustained arc plasma chemical reactor fabricates very-fine-grained inorganic solids having low thermal conductivity. Powder fabrication method, based on plasma tube technique produces pure solids without contamination commonly produced by grinding.

  1. Continuous blending of dry pharmaceutical powders

    E-print Network

    Pernenkil, Lakshman

    2008-01-01

    Conventional batch blending of pharmaceutical powders coupled with long quality analysis times increases the production cycle time leading to strained cash flows. Also, scale-up issues faced in process development causes ...

  2. Advances in beryllium powder consolidation simulation

    SciTech Connect

    Reardon, B.J.

    1998-12-01

    A fuzzy logic based multiobjective genetic algorithm (GA) is introduced and the algorithm is used to optimize micromechanical densification modeling parameters for warm isopressed beryllium powder, HIPed copper powder and CIPed/sintered and HIPed tantalum powder. In addition to optimizing the main model parameters using the experimental data points as objective functions, the GA provides a quantitative measure of the sensitivity of the model to each parameter, estimates the mean particle size of the powder, and determines the smoothing factors for the transition between stage 1 and stage 2 densification. While the GA does not provide a sensitivity analysis in the strictest sense, and is highly stochastic in nature, this method is reliable and reproducible in optimizing parameters given any size data set and determining the impact on the model of slight variations in each parameter.

  3. Infrared and Raman microspectrometry study of fluor-fluor-hydroxy and hydroxy-apatite powders.

    PubMed

    Penel, G; Leroy, G; Rey, C; Sombret, B; Huvenne, J P; Bres, E

    1997-05-01

    Visible Raman and infrared microspectrometry studies performed on fluorapatite and hydroxyapatite powders have shown similar results. Small modifications of the nu2 and nu4 PO(3-)4 tetrahedra bending modes are observed. A small frequency shift of the nu1 mode and modifications on the nu3 mode region accompanied with a simplification of the hydroxyapatite and fluorapatite respective spectra from seven to four bands were observed. A broad and weak band which could be attributed to the Ca-F bond is detected at 311 cm(-1) on the Raman fluorapatite spectra. The phosphate vibration modes are little disturbed by fluoride substitution. This could indicate that phosphate groups interact strongly between themselves and weakly with substituted atoms (i.e. hydroxyle and fluoride atoms). Whatever crystallographic model is considered, the number of bands observed is always lower than the number of calculated ones, even for hydroxyapatite, whose symmetry is lower than that of fluorapatite. PMID:15348748

  4. Feedstock development for micro powder injection molding

    Microsoft Academic Search

    L. Merz; S. Rath; V. Piotter; R. Ruprecht; J. Ritzhaupt-Kleissl; J. Hausselt

    2002-01-01

    Powder injection molding of microstructured parts with high aspect ratios requires feedstocks, which have a high mechanical\\u000a stability for demolding. The binders of the feedstocks have to allow pressure free and complete debinding and sintering without\\u000a deformation in the submillimeter range. For complete molding of especially small and complex detailed microstructures, powders\\u000a with a small particle size have to be

  5. Method and Apparatus for Production of Powders

    NASA Technical Reports Server (NTRS)

    Storltzfus, Joel M. (Inventor); Sircar, Subhasish (Inventor)

    1998-01-01

    Apparatus and method are disclosed for producing oxides of metals and of metal alloys. The metal or alloy is placed in an oxygen atmosphere in a combustion chamber and ignited. Products of the combustion include one or more oxides of the metal or alloy in powdered form. In one embodiment of the invention a feeder is provided whereby material to be oxidized by combustion can be advanced into a combustion chamber continuously. A product remover receives the powder product of the combustion.

  6. Method and apparatus for production of powders

    NASA Technical Reports Server (NTRS)

    Stolzfus, Joel M. (inventor.); Sircar, Subhasish (inventor.)

    1995-01-01

    Apparatus and method are disclosed for producing oxides of metals and of metal alloys. The metal or alloy is placed in an oxygen atmosphere in a combustion chamber and ignited. Products of the combustion include one or more oxides of the metal or alloy in powdered form. In one embodiment of the invention a feeder is provided whereby material to be oxidized by combustion can be advanced into a combustion chamber continuously. A product remover receives the powder product of the combustion.

  7. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit (Knoxville, TN); Williams, Robert K. (Knoxville, TN)

    2001-01-01

    A biaxially textured alloy article comprises Ni powder and at least one powder selected from the group consisting of Cr, W, V, Mo, Cu, Al, Ce, YSZ, Y, Rare Earths, (RE), MgO, CeO.sub.2, and Y.sub.2 O.sub.3 ; compacted and heat treated, then rapidly recrystallized to produce a biaxial texture on the article. In some embodiments the alloy article further comprises electromagnetic or electro-optical devices and possesses superconducting properties.

  8. Pulsed laser deposition of strontium-substituted hydroxyapatite coatings

    NASA Astrophysics Data System (ADS)

    Pereiro, I.; Rodríguez-Valencia, C.; Serra, C.; Solla, E. L.; Serra, J.; González, P.

    2012-09-01

    The growing evidence of the beneficial role of strontium in bone has increased the interest of developing strontium-containing biomaterials for medical applications, and specifically biocompatible coatings that can be deposited on metallic implants to benefit from their load-bearing capabilities. In this work, strontium-substituted hydroxyapatite (Sr-HA) coatings have been fabricated by pulsed laser deposition (PLD) from initial targets obtained after mixing and compacting commercial HA and SrCO3 powders in different proportions. The films thus fabricated were then structurally, morphologically and chemically characterized using scanning electron microscopy, optical profilometry, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The macroscopic morphology of the films presented in all cases equivalent spherical shaped aggregates of typical calcium phosphate coatings. The results reveal, however, the incorporation of Sr2+ and carbonate groups in the coatings as a function of the SrCO3 content in the ablation target, being the incorporation of Sr2+ a linear phenomenon that is accompanied by a similarly linear withdrawal of Ca2+. The role of Sr2+ in the modification of the HA structure and a possible mechanism of substitution of Sr2+ atoms in place of Ca2+ atoms are discussed.

  9. Does electrostatic charge affect powder aerosolisation?

    PubMed

    Adi, Handoko; Kwok, Philip Chi Lip; Crapper, John; Young, Paul M; Traini, Daniela; Chan, Hak-Kim

    2010-05-01

    To study if electrostatic charge initially present in mannitol powder plays a role in the generation of aerosols, mannitol was unipolarly charged to varying magnitudes by tumbling the powder inside containers of different materials. The resulting charge in the powder was consistent with predictions from the triboelectric charging theories, based on the work function values from literature and electron transfer tendencies from measurement of contact angle. The latter generated a parameter, gamma(-)/gamma+, which is a measure of the electron-donating capacity relative to the electron-accepting tendency of material. Lowering the work function value or increasing the gamma(-)/gamma+ ratio of the container material resulted in mannitol being more negatively charged, and vice versa. After charging, the powder was dispersed from an Aerolizer(R), at 30 and 60 L/min, to study the aerosol performance. Irrespective of the charge level, the powder showed similar fine particle fraction, emitted dose and device retention at a given flow rate, indicating that charge induced by different containers during tumbling does not play a significant role in mannitol powder aerosolisation. PMID:19941330

  10. Electrostatic charge interactions in ordered powder mixes.

    PubMed

    Staniforth, J N; Rees, J E

    1982-02-01

    A method is described for measuring the electrostatic charge generated in powders following contact with a plane substrate. The method uses a Faraday well connected to an electrometer and allows the specific charge of powders to be determined. Of the various drugs and excipients studied, most charged electronegatively following contact with glass surfaces, but became electropositive after contact with polyethylene surfaces. The charge interactions of drug and excipient powders modified the behaviour of ordered mixes formed in similar conditions to those of charge measurement. Powders with like charges formed less stable ordered mixes than those in which drug and excipient particles carried opposite charges. Following triboelectrification in an air cyclone constructed of brass, powders had charges at least 100 times greater than those formed after contact with glass surfaces. Optimization of the triboelectric charging conditions allowed ordered mixes to be prepared in which a maximum electronegative charge was applied to the excipient whilst the drug was given a maximum electropositive charge. Studies of segregation/stability showed that ordered mixes subjected to triboelectrification were less prone to segregation than uncharged powders. PMID:6121883

  11. Hydrothermal synthesis and characterization of Si and Sr co-substituted hydroxyapatite nanowires using strontium containing calcium silicate as precursors.

    PubMed

    Zhang, Na; Zhai, Dong; Chen, Lei; Zou, Zhaoyong; Lin, Kaili; Chang, Jiang

    2014-04-01

    In the absence of any organic surfactants and solvents, the silicon (Si) and strontium (Sr) co-substituted hydroxyapatite [Ca10(PO4)6(OH)2, Si/Sr-HAp] nanowires were synthesized via hydrothermal treatment of the Sr-containing calcium silicate (Sr-CS) powders as the precursors in trisodium phosphate (Na3PO4) aqueous solution. The morphology, phase, chemical compositions, lattice constants and the degradability of the products were characterized. The Si/Sr-HAp nanowires with diameter of about 60nm and up to 2?m in length were obtained after hydrothermal treatment of the Sr-CS precursors. The Sr and Si substitution amount of the HAp nanowires could be well regulated by facile tailoring the Sr substitution level of the precursors and the reaction ratio of the precursor/solution, respectively. The SiO4 tetrahedra and Sr(2+) ions occupied the crystal sites of the HAp, and the lattice constants increased apparently with the increase of the substitution amount. EDS mapping also suggested the uniform distribution of Si and Sr in the synthetic nanowires. Moreover, the Si/Sr-substitution apparently improved the degradability of the HAp materials. Our study suggested that the precursor transformation method provided a facile approach to synthesize the Si/Sr co-substituted HAp nanowires with controllable substitution amount, and the synthetic Si/Sr-HAp nanowires might be used as bioactive materials for hard tissue regeneration applications. PMID:24582251

  12. The effects of race on patient preferences and spouse substituted judgments.

    PubMed

    Pruchno, Rachel; Cartwright, Francine P; Wilson-Genderson, Maureen

    2009-01-01

    Knowledge about the ways in which race affects decision-making at the end of life is minimal, yet this information is critical for providing culturally sensitive care at the end of life. Data matching socio-demographic characteristics of 34 black and 34 white patients with end-stage renal disease and their spouses reveal that there are no significant differences in the preferences to continue dialysis on the part of black and white patients. However, the substituted judgments of black and white spouses differ from one another, with black spouses being more likely to indicate that they believe that the patient would be more inclined to continue dialysis under a host of hypothetical conditions than white spouses. Structural equation modeling analyses revealed that differences in spouse substituted judgments between black and white spouses are explained as a direct function of race differences in perception of patient's health, and caregiver burden, and that indirect effects are associated with spouse's fear of death and participation in religious services. We conclude that these variables rather than race per se explain differences in end of life decision making. PMID:19803339

  13. Black hole masking and black hole thermodynamics

    E-print Network

    Oleg B. Zaslavskii

    2011-02-20

    Masking of black holes means that, for given total mass and Hawking temperatures, these data may correspond to either "pure" black hole or a black hole of a lesser mass surrounded by a massive shell. It is shown that there is one-to one correspondence between this phenomenon and thermodynamics of a black hole in a finite size cavity: masking of black holes is possible if and only if there exists at least one locally unstable black hole solution in the corresponding canonical ensemble.

  14. Monopole Black Hole Skyrmions

    E-print Network

    Ian G Moss; N Shiiki; E Winstanley

    2000-05-02

    Charged black hole solutions with pion hair are discussed. These can be used to study monopole black hole catalysis of proton decay. There also exist multi- black hole skyrmion solutions with BPS monopole behavior.

  15. Black Widow Spider

    MedlinePLUS

    ... slow absorption of the venom. Identification • The female black widow is normally shiny black, with a red hourglass marking (see photo) on ... to a dot. • The body of an adult black widow female is about 1 /2inch long. Habitat ...

  16. Black Smokers

    NSDL National Science Digital Library

    This webpage contains a brief introduction to the discovery of hydrothermal systems and black smokers. Within the webpage are links to information on gigantic tube worms, polychaete worms, oceans, and extreme environments. This site also provides a list of hydrothermal systems, relevant links to organizations, laboratories and observatories, WebQuests, and other websites with further information on hydrothermal systems. As part of the Environmental Literacy Council site, this webpage also contains links to other resources with environmental content, including air climate, land, water, ecosystems, energy, food, and environment and society.

  17. Use This Test to Spruce Up Your Substitute Teacher Program.

    ERIC Educational Resources Information Center

    Sendor, Elizabeth

    1982-01-01

    Presents and interprets an 18-question test to determine how well a school's substitute teacher program functions. Topics covered include substitute teacher screening and preparation, lists of substitutes, lesson plans, staff and student evaluation of substitutes, substitutes' salaries, legal considerations, and making substitutes feel needed.…

  18. January 2013 BEE CULTURE 23 Revisiting Powdered Sugar For

    E-print Network

    Delaplane, Keith S.

    January 2013 BEE CULTURE 23 Revisiting Powdered Sugar For Varroa Control On Honey Bees (Apis dust bees with powder sugar as a means of removing mites. Dusting with powder sugar was also gaining conducted a study which examined the efficacy of powder sugar and found it did not help in controlling

  19. Effect of powder loading on metal injection molding stainless steels

    Microsoft Academic Search

    Yimin Li; Liujun Li; K. A. Khalil

    2007-01-01

    Powder loading is one of the most critical factors which has important influence on metal injection molding processes. Using the gas atomized spherical 17-4 PH stainless steel powder and the binder of 65% PW+30% EVA+5% SA, four kinds of feedstocks were prepared at the powder loading of 60, 64, 68 and 72%, respectively. The effects of the powder loading on

  20. Star-anise ( Illicium verum) and black caraway ( Carum nigrum) as natural antioxidants

    Microsoft Academic Search

    A. Padmashree; N. Roopa; A. D. Semwal; G. K. Sharma; G. Agathian; A. S. Bawa

    2007-01-01

    The various solvent fractions of star-anise (Illicium verum) and black caraway (Carum nigrum), along with their spice powders and volatile oils, were prepared and evaluated for antioxygenic activity, using different methods. Star-anise powder and its ethanol\\/water (80:20)-soluble fraction showed strong antioxygenic activity in refined sunflower oil while the petroleum ether fraction exhibited marginal antioxygenic activity and the water-soluble fraction was

  1. X-ray photoelectron spectroscopy indication of decomposition species in the residue of shocked polytetrafluoroethylene powder

    NASA Astrophysics Data System (ADS)

    Holt, W. H.; Mock, W.; Santiago, F.

    2000-11-01

    Forty-eight percent porous polytetrafluoroethylene (PTFE) powder placed inside a steel closed container has been impact shock loaded with a gas gun and soft recovered. The initial stress in the powder is calculated to be 7.2 kbar. The residue in the container showed dark regions where the originally white powder had decomposed to form black soot. X-ray photoelectron spectroscopy (XPS) was used to analyze in situ a portion of a dark region. The resulting spectrum showed a large amorphous carbon peak that was not observed in the unshocked powder spectrum. In addition, the shocked material showed several peaks containing hydrogen and/or oxygen, suggesting reactions of dissociation products with ambient air and/or water vapor in the polymer pores or possibly with residual water in the polymer. (The residual gas analyzer in the XPS system detected water vapor in the unshocked specimen.) Both spectra showed peaks corresponding to the PTFE linear polymer chain F-C-F.

  2. Dielectric and Polarization Studies of Ca Substituted in Bi4SrTi4O15 Ceramics

    Microsoft Academic Search

    Gagan Anand; A. R. James; P. Sarah

    2010-01-01

    The processing conditions, microstructure and dielectric properties of strontium bismuth titanate (SBT) were studied by means of Ca substitution in the strontium site referred to hereinafter as SCBT. The mechano-chemical activation method permits one to reduce the particle size of the initial products, so the surface area of the powder is increased, improving in most cases its reactivity.X-ray diffraction analysis

  3. What Is This Black in Black Diaspora?

    Microsoft Academic Search

    Michelle Stephens

    2009-01-01

    Looking back at the dialogue between Black British Cultural Studies and African American Studies that occurred during the 1980s and 1990s, when Stuart Hall first asked the question, “What is this black in black popular culture?” this article explores how that conversation has evolved in the context of current discussions of black cross-culturality and diaspora. New concerns have emerged about

  4. Black hole masking and black hole thermodynamics

    Microsoft Academic Search

    Oleg B. Zaslavskii

    2011-01-01

    Masking of black holes means that, for given total mass and Hawking temperatures, these data may correspond to either a “pure”\\u000a black hole or a black hole of smaller mass surrounded by a massive shell. It is shown that there is a one-to one correspondence\\u000a between this phenomenon and thermodynamics of a black hole in a finite size cavity: masking

  5. Slip casting nano-particle powders for making transparent ceramics

    DOEpatents

    Kuntz, Joshua D. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Landingham, Richard Lee (Livermore, CA); Hollingsworth, Joel P. (Oakland, CA)

    2011-04-12

    A method of making a transparent ceramic including the steps of providing nano-ceramic powders in a processed or unprocessed form, mixing the powders with de-ionized water, the step of mixing the powders with de-ionized water producing a slurry, sonifing the slurry to completely wet the powder and suspend the powder in the de-ionized water, separating very fine particles from the slurry, molding the slurry, and curing the slurry to produce the transparent ceramic.

  6. Hysteresis and creep in powdersHysteresis and creep in powders and grainsand grains

    E-print Network

    Harting, Jens

    Hysteresis and creep in powdersHysteresis and creep in powders and grainsand grains Ciprian David. Model usedDiscrete element methods. Model used Micromechanical investigation of granular soilsMicromechanical investigation of granular soils under cyclic loadingunder cyclic loading ConclusionsConclusions #12;Motivation

  7. Black Secularism and Black Theology Vincent Lloyd

    E-print Network

    Doyle, Robert

    "white theology" as a major threat not only to black Christians but to Christianity in general. In 1970, by the existence today of black scholars talking about Christianity. The trouble is that in many cases those black familiar that it has lost its punch. For prophetic Christianity to be revivified, Glaude insists, prophecy

  8. Black hole excision for dynamic black holes

    Microsoft Academic Search

    Miguel Alcubierre; Bernd Brügmann; Denis Pollney; Edward Seidel; Ryoji Takahashi

    2001-01-01

    We extend the previous work on 3D black hole excision to the case of distorted black holes, with a variety of dynamic gauge conditions that respond naturally to the spacetime dynamics. We show that in evolutions of highly distorted, rotating black holes, the combination of excision and the gauge conditions we use is able to drive the coordinates to a

  9. Black Hessians: American Blacks as German Soldiers.

    ERIC Educational Resources Information Center

    Hoffman, Elliott W.

    1981-01-01

    The German army in America during the Revolutionary War enlisted Blacks as musicians, laborers, and soldiers. Black soldiers contributed to the mercenaries' military activities, while the German units offered Blacks employment, clothing, food, and a type of escape from slavery. (Author/MJL)

  10. Large-scale and shape-controlled synthesis and characterization of nanorod-like nickel powders under microwave radiation

    SciTech Connect

    Guo, Yajie [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China)] [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China); Wang, Guangjian, E-mail: wgj2260@chnu.edu.cn [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China)] [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China); Wang, Yuran [School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai 200030 (China)] [School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai 200030 (China); Huang, Yanhong [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China)] [School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, Anhui (China); Wang, Fei [School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai 200030 (China)] [School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai 200030 (China)

    2012-01-15

    Graphical abstract: The nanorod-like pure nickel were fabricated via hydrothermal liquid phase reduction route under microwave irradiation with hydrazine hydrate as a reducing agent as well as polyvinyl alcohol as a dispersant and/or structure directing agent. The materials were characterized by XRD, SEM, EDS, HRTEM, and selected-area electron diffraction, etc. The lattice expansion for Ni powders was explained in detail. As-prepared Ni sample was of obvious shape anisotropy with length diameter ratio of 5. Magnetic measurements shown that the magnetic properties of Ni nanorod-like (fcc) were quite different from those of hexagonal closed-packed (hcp) Ni nanoparticles. Highlights: Black-Right-Pointing-Pointer The synthesis of nanorod-like nickel under microwave irradiation. Black-Right-Pointing-Pointer Nitrogen generated in reaction as a shielding gas. Black-Right-Pointing-Pointer The lattice expansion for Ni powders was explained in detail. Black-Right-Pointing-Pointer Magnetic properties of Ni were quite different from those of Ni nanoparticles. -- Abstract: The nanorod-like nickel powders were fabricated via hydrothermal liquid phase reduction route under microwave irradiation with hydrazine hydrate as a reducing agent as well as polyvinyl alcohol as a dispersant and/or structure directing agent. The morphology and structure of as-prepared products could be easily tuned by adjusting process parameters such as pH value and microwave irradiation time. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscope, transmission electron microscopy and selected-area electron diffraction (SAED). The results demonstrated that pure nickel powders with face-centered cubic (fcc) structure were prepared at relatively mild condition and no characteristic peaks of nickel oxide in the XRD pattern were found. The phenomenon of lattice expansion for Ni powders was explained in details according to the XRD theory. As-prepared Ni sample was of obvious shape anisotropy with length diameter ratio of 5. Magnetic measurements shown that the magnetic properties of nanorod-like (fcc) Ni powders were quite different from those of hexagonal closed-packed (hcp) Ni nanoparticles. Furthermore, it had more strong ferromagnetic properties than that of Ni powders both bulk and nanoparticles.

  11. Evaluation of antioxidant, rheological, physical and sensorial properties of wheat flour dough and cake containing turmeric powder.

    PubMed

    Park, S H; Lim, H S; Hwang, S Y

    2012-10-01

    The effects of addition of turmeric powder (0%, 2%, 4%, 6% and 8%) were examined in order to obtain an antioxidant-enriched cake with good physico-chemical and sensorial properties. The rheological properties of doughs were evaluated using dynamic rheological measurements. Physical properties, curcumin content, radical scavenging activity (RSA-DPPH assay) and sensory analysis (hedonic test) of the supplemented cake were determined. Addition of turmeric powder up to 8% caused significant changes on dough characteristics and on cake rheological properties. The highest curcumin (203?mg/kg) and RSA-DPPH activity (45%) were achieved in the cake having the highest percentage of turmeric powder (8%); however, this sample showed the worst results regarding the rheological properties. Moreover, by sensory evaluation this cake sample was not acceptable. A 6% substitution of wheat flour with turmeric powder showed acceptable sensory scores which were comparable to those of 0-4% turmeric cakes. This indicated that up to 6% level of turmeric powder might be included in cake formulation. PMID:23144239

  12. Dynamic compaction of tungsten carbide powder.

    SciTech Connect

    Gluth, Jeffrey Weston; Hall, Clint Allen; Vogler, Tracy John; Grady, Dennis Edward

    2005-04-01

    The shock compaction behavior of a tungsten carbide powder was investigated using a new experimental design for gas-gun experiments. This design allows the Hugoniot properties to be measured with reasonably good accuracy despite the inherent difficulties involved with distended powders. The experiments also provide the first reshock state for the compacted powder. Experiments were conducted at impact velocities of 245, 500, and 711 m/s. A steady shock wave was observed for some of the sample thicknesses, but the remainder were attenuated due to release from the back of the impactor or the edge of the sample. The shock velocity for the powder was found to be quite low, and the propagating shock waves were seen to be very dispersive. The Hugoniot density for the 711 m/s experiment was close to ambient crystal density for tungsten carbide, indicating nearly complete compaction. When compared with quasi-static compaction results for the same material, the dynamic compaction data is seen to be significantly stiffer for the regime over which they overlap. Based on these initial results, recommendations are made for improving the experimental technique and for future work to improve our understanding of powder compaction.

  13. X-ray resonant powder diffraction

    NASA Astrophysics Data System (ADS)

    Palancher, H.; Bos, S.; Bérar, J. F.; Margiolaki, I.; Hodeau, J. L.

    2012-06-01

    X-ray resonant diffraction can be applied in structural chemistry studies on powder samples. It enables an important limitation of powder diffraction to be overcome. This limitation is related to the low ability of powder diffraction to differentiate elements with close atomic numbers when they occupy the same or close crystallographic sites (mixed occupancy case) and also to discriminate cations with different valence states in different sites. However the resonant effect usually has a second order influence on the measured intensity. As a consequence, the efficiency of this method directly implies the need for excellent quality data collection and has generally been better assessed on elements present in single phase powder samples. In recent years, instrumental developments have been made in synchrotron radiation facilities which allow easier use of resonant powder diffraction for site-specific contrast and valence i.e. oxidation state analyses. Moreover, resonant contrast diffraction tools also have been proposed for better visualization of the anomalous effect both in direct and reciprocal space by using differences between electron density maps or diffraction patterns. Finally the potentialities of this technique for de novo structure solution on macromolecular systems are mentioned.

  14. Die-target for dynamic powder consolidation

    DOEpatents

    Flinn, John E. (Idaho Falls, ID); Korth, Gary E. (Blackfoot, ID)

    1986-01-01

    A die/target is disclosed for consolidation of a powder, especially an atomized rapidly solidified metal powder, to produce monoliths by the dynamic action of a shock wave, especially a shock wave produced by the detonation of an explosive charge. The die/target comprises a rectangular metal block having a square primary surface with four rectangular mold cavities formed therein to receive the powder. The cavities are located away from the geometrical center of the primary surface and are distributed around such center while also being located away from the geometrical diagonals of the primary surface to reduce the action of reflected waves so as to avoid tensile cracking of the monoliths. The primary surface is covered by a powder retention plate which is engaged by a flyer plate to transmit the shock wave to the primary surface and the powder. Spawl plates are adhesively mounted on other surfaces of the block to act as momentum traps so as to reduce reflected waves in the block.

  15. Bone substitutes in oral surgery.

    PubMed

    Pappalardo, S; Puzzo, S; Carlino, V; Cappello, V

    2007-10-01

    Osseous defects pose a clinical challenge the operator can meet with the aid of techniques that promote bone tissue regeneration. The current gold standard is autologous bone harvested from intra- and extraoral donor sites; however, autologous bone grafting requires two surgical sites (donor and recipient), resulting in greater morbidity and prolonged operating times, particularly for extraoral sites, with greater discomfort for the patient. Such disadvantages can be overcome with the use of bone substitute materials. There is a notable variety of so-called intelligent biomaterials that can modulate bone response in regeneration. Based on origin, bone substitute materials are classified as allogenic, heterologous and alloplastic materials. The first refer to bone from same-species donors, the second are obtained through processing of bone from different species, while alloplastic materials are synthetic composites. Besides different resorption rates, they possess different chemical and structural characteristics that influence the stimulation or support of bone regeneration. In daily clinical practice, before selecting from the wide variety of biomaterials, a wise step is to analyze and compare the clinical and histological results obtained with these materials. This article examines the clinical applications and osteoconductive and/or osteoinductive properties of some currently available biomaterials. PMID:18091669

  16. Slip Casting of ?-Sialon/AlN/BN Powder Carbothermally Prepared by Boron-rich Slag-based Mixture

    NASA Astrophysics Data System (ADS)

    Jun-bin, Wu; Xiang-xin, Xue; Tao, Jiang; Qing, Zhang

    2011-10-01

    With boron-rich slag, silica fume, bauxite chalmette and carbon black as starting materials, ?-Sialon/AlN/BN powder was prepared by carbothermal reduction-nitridation. The powder was attrition milled to submicron size and suspended in water. The effects of yttrium oxide as a sintering aid, pH, and addition of deflocculant on the suspensions were study. Optimum slip casting properties, i.e. lowest viscosity values, the highest absolute zeta potential values, the smallest floc size and sediment volume were found at pH 10 for the powder. The suspensions were used to slip cast discs which were sintered in a nitrogen atmosphere at 1700°C for 2h. The strength was about 230MPa, the toughness 3.6 MPa·m1/2 and the hardness about 13.8GPa.

  17. Black Box

    NSDL National Science Digital Library

    In this activity students observe what happens when various amounts of water are poured into a black box and propose models to explain their observations. When water is poured into the funnel, students observe that sometimes water emerges through the outlet tube and sometimes it does not. Also, the amount of water that does emerge is not constant. Students share their initial ideas with others and offer criticism to peers. They prepare and present a poster of their final, revised models. The activity involves data collection, pattern recognition, and model building. Supplemental student activities, such as a pattern recognition activity and a model reading, are used to provide explicit instruction about individual components of model building and assessment. The site includes links to instructional notes, student activities, assessment, and student work examples.

  18. Substituting objects from consciousness: a review of object substitution masking.

    PubMed

    Goodhew, Stephanie C; Pratt, Jay; Dux, Paul E; Ferber, Susanne

    2013-10-01

    Object substitution masking (OSM) occurs when a sparse (e.g., four-dot), temporally trailing mask obscures the visibility of a briefly presented target. Here, we review theories of OSM: those that propose that OSM reflects the interplay between feedforward and feedback/reentrant neural processes, those that predict that feedforward processing alone gives rise to the phenomenon, and theories that focus on cognitive explanations, such as object updating. We discuss how each of these theories accommodates key findings from the OSM literature. In addition, we examine the relationship between OSM and other visual-cognitive phenomena, including object correspondence through occlusion, change blindness, metacontrast masking, backward masking, and visual short-term memory. Finally, we examine the level of processing at which OSM impairs target perception. Collectively, OSM appears to reflect the conditions under which the brain confuses two visual events for one when they are encoded with low spatiotemporal resolution, due to processing resources being otherwise occupied. PMID:23417271

  19. Synthesis of La-Co Substituted M-type Calcium Hexaferrite by Polymerizable Complex Method

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.; Nakamura, T.; Yamasaki, T.; Nakanishi, M.; Fujii, T.; Takada, J.; Ikeda, Y.

    2011-10-01

    Synthesis of La-Co substituted M-type Calcium hexaferrite was studied. Samples were prepared by polymerizable complex method. High purity reagent of strontium carbonate, iron (III) nitrate ennnahydrate, cobalt (II) nitrate hexahydrate and lanthanum oxide were used as starting materials. Prepared aqueous solution was heated for dehydration and gelling. Thermal pyrolysis was carried out by heating the gel. The obtained precursor powders were ground with an alumina mortar and compacted by uniaxial pressing into disk specimens and then heated at temperature range between 1173 K and 1573 K in air. Phase identification and determination of lattice parameters were carried out by powder X-ray diffraction (XRD). Scanning Electron Microscope (SEM) was utilized to investigate the microstructure of the polycrystalline ferrites. Magnetic properties were discussed by magnetization measurements by measuring of M-H curve with vibrating sample magnetometer (VSM). Single-phase of M-type hexaferrite was obtained at lower temperature relative to by conventional synthesis.

  20. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-10-21

    A strengthened, biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed, compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: Ni, Ag, Ag--Cu, Ag--Pd, Ni--Cu, Ni--V, Ni--Mo, Ni--Al, Ni--Cr--Al, Ni--W--Al, Ni--V--Al, Ni--Mo--Al, Ni--Cu--Al; and at least one fine metal oxide powder; the article having a grain size which is fine and homogeneous; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  1. Reactive plasma atomization of aluminum nitride powder

    SciTech Connect

    Prichard, P.; Besser, M.; Sordelet, D.; Anderson, I.

    1997-02-01

    Experiments were performed to synthesize AlN powders by reacting Al with N using a conventional dc arc plasma as heat source. Feeding Al powder into Ar/N plasma open to atmosphere produced mainly Al oxide. Experiments using a chamber backfilled with nitrogen suppressed the Al oxide, but little AlN was formed. A furnace and crucible assembly was designed to feed molten Al directly into a DeLaval nozzle attached to the face of the dc arc plasma gun. Resulting submicron powders show a significant increase in AlN formation. This was dependent on chamber pressure, plasma velocity, and molten liquid feed rate. Experimental parameters, equipment design, effects of atomization/vaporization/condensation are discussed.

  2. Preparation of nickel powders in nonaqueous media.

    NASA Astrophysics Data System (ADS)

    Macek, Jadran; Degen, Andrej

    Precipitation of nickel powder is usually carried out in aqueous media. Nonaqueous solvents such as ethanolamines offer several advantages. The effective temperature range extends to the higher temperatures needed for the reduction of nickel at atmospheric pressure, a reaction that is also facilitated by the basicity of the medium. Tests were carried out for the preparation of submicrometre nickel powders by the reduction of metal salts using various ethanolamines (monoethanolamine - MEA, diethanolamine - DEA, and triethanolamine - TEA) as solvents. Hydrazine (N2H4) was used as the reducing agent. The basicity, polarity, viscosity and boiling point of the reaction medium all affect the reactions. By changing the reaction conditions and the anionic component of the precursor salt, it was possible to alter the purity and morphology of the nickel powders obtained and the average particle size, except in the case of MEA where no reduction occured. The products were subsequently characterised by chemical analysis and by scanning electron microscopy.

  3. Metrology Needs for Metal Additive Manufacturing Powders

    NASA Astrophysics Data System (ADS)

    Slotwinski, John A.; Garboczi, Edward J.

    2015-03-01

    Additive manufacturing (AM) processes can produce highly complex and customized parts without the need for dedicated tooling and can produce parts directly from the part design information. These types of processes are poised to revolutionize the manufacturing industry, yet several challenges are currently preventing more widespread adoption of AM technologies. Among these challenges are metrology issues associated with the measurement and characterization of the metal powders used for AM systems. This article will describe the technical challenges and needs for characterizing metal AM powders, recent research efforts to address those needs, and current work to standardize characterization methods in ASTM and ISO, such as the recently released ASTM F3049, Standard Guide for Characterizing Properties of Metal Powders Used for Additive Manufacturing Processes.

  4. Nitridation of chromium powder in ammonia atmosphere

    NASA Astrophysics Data System (ADS)

    Li, Ling; Zhen, Qiang; Li, Rong

    2015-03-01

    CrN powder was synthesized by nitriding Cr metal in ammonia gas flow, and its chemical reaction mechanism and nitridation process were studied. Through thermodynamic calculations, the Cr-N-O predominance diagrams were constructed for different temperatures. Chromium nitride formed at 7002-1200°C under relatively higher nitrogen and lower oxygen partial pressures. Phases in the products were then investigated using X-ray diffraction (XRD), and the Cr2N content varied with reaction temperature and holding time. The results indicate that the Cr metal powder nitridation process can be explained by a diffusion model. Further, Cr2N formed as an intermediate product because of an incomplete reaction, which was observed by high-resolution transmission electron microscopy (HRTEM). After nitriding at 1000°C for 20 h, CrN powder with an average grain size of 63 nm was obtained, and the obtained sample was analyzed by using a scanning electron microscope (SEM).

  5. Volume 7. Copper base powder metallurgy

    SciTech Connect

    Taubenblat, P.W. (ed.)

    1980-01-01

    This book is based on a series of lectures on copper and copper base P/M materials sponsored by the Metal Powder Industries Federation. It covers recent developments in the fields of copper powder metallurgy and offers a comprehensive survey of copper and copper-base P/M materials. It begins with a chapter on the production of copper and copper alloy powders followed by discussions of specific applications of P/M materials in bronzes and bearings, in brasses and nickel silvers, and in electrically conductive parts. Also discussed are iron composition containing copper, copper-based alloys for infiltration of iron and other special copper-base alloys. It concludes with chapters on consolidation, sintering and review of specifications.

  6. Crystal structure and magnetic properties of Pr- and Ti-substituted La{sub 2}RuO{sub 5}

    SciTech Connect

    Riegg, S., E-mail: stefan.riegg@physik.uni-augsburg.de [Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86159 Augsburg (Germany); Loidl, A. [Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, D-86159 Augsburg (Germany); Reller, A. [Resource Strategy, University of Augsburg, D-86159 Augsburg (Germany); Ebbinghaus, S.G. [Solid State Chemistry, Martin-Luther University Halle-Wittenberg, D-06099 Halle (Germany)

    2013-11-15

    Highlights: • Synthesis of polycrystalline Pr and Ti co-substituted La{sub 2}RuO{sub 5} with soft chemistry. • Investigation of structure–property relationship of the dimerization transition. • Additive behavior of structural changes caused by either Pr or Ti substitution. • Additive behavior of ht-phase paramagnetism of Pr and Ti substitution. • Additive influence of Pr and Ti substitution on the dimerization transition. - Abstract: Polycrystalline samples of Pr- and Ti-substituted La{sub 2}RuO{sub 5} were prepared applying a soft-chemistry route based on the thermal decomposition of citrate-stabilized precursors. The simultaneous substitution on the La-sites by Pr and on the Ru-sites by Ti results in samples of the composition La{sub 2?x}Pr{sub x}Ru{sub 1?y}Ti{sub y}O{sub 5} with 0 ? x ? 0.75 and 0 ? y ? 0.4. The crystal structures of these compounds were analyzed by Rietveld refinement of powder X-ray diffraction patterns. For pure La{sub 2}RuO{sub 5} a structural transition from a monoclinic room-temperature modification to a triclinic low-temperature structure was found at 161 K. This structural change is linked to a low-temperature long-range ordered spin-singlet ground state formed by Ru{sup 4+} spin-moments. Both the structural transition and the formation of the singlet ground state become progressively suppressed with higher Ti contents, while the Pr substitution has only a minor influence on the dimerization. The behavior of the Curie–Weiss temperatures can be explained assuming two almost independent magnetic sublattices corresponding to the ruthenium and the rare-earth ions, respectively. For all investigated properties, i.e. crystal structure, magnetic susceptibilities, and dimerization temperature T{sub d}, a completely additive behavior of the effects of Pr-substitution and Ti-substitution is observed.

  7. Noncommutative black holes

    NASA Astrophysics Data System (ADS)

    López-Domínguez, J. C.; Obregón, O.; Ramírez, C.; Sabido, M.

    2007-11-01

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the "noncommutative" Schwarzschild black hole.

  8. Black Feminist Theory

    Microsoft Academic Search

    Evelyn M. Simien

    2004-01-01

    Black feminist consciousness arises from an understanding of intersecting patterns of discrimination. If race and gender are studied as separate categories, one cannot explain how attitudes might change as a result of cross-pressures to subordinate the interests of black women so as to protect black men. In this essay, I start with a discussion of black feminist consciousness, providing an

  9. Graduating Black Males

    ERIC Educational Resources Information Center

    Bell, Edward Earl

    2010-01-01

    Background: The graduation numbers for Black males are dismal, chilling, and undeniably pathetic. The nation graduates only 47% of Black males who enter the 9th grade. The infusion of federal dollars and philanthropic support will not stop the trajectory of Black males who drop out of school. Black males face an upheaval educational battle;…

  10. Black Holes FAQ

    NSDL National Science Digital Library

    Bunn, Ted

    This website contains a list of Frequently Asked Questions about Black Holes. The goal is to answer the common, and not so common, doubts about Black Holes, such as their origin, properties, and fate. It also deals with gravitational effects of Black Holes, and the concepts of White Holes and Wormholes. It provides rationale for existence of Black Holes despite lack of direct observation.

  11. Black hole binaries

    Microsoft Academic Search

    Jeffrey E. McClintock; Ronald A. Remillard

    2006-01-01

    We review the properties of 40 X-ray binaries that contain either a confirmed black hole or a black hole candidate. After discussing briefly the significance of these Galactic black holes to both astronomy and physics, we present basic data for all 40 systems, review the physics of mass accretion onto black holes, and then show seven-year light curves of 20

  12. Atomization methods for forming magnet powders

    DOEpatents

    Sellers, Charles H. (Idaho Falls, ID); Branagan, Daniel J. (Idaho Falls, ID); Hyde, Timothy A. (Idaho Falls, ID)

    2000-01-01

    The invention encompasses methods of utilizing atomization, methods for forming magnet powders, methods for forming magnets, and methods for forming bonded magnets. The invention further encompasses methods for simulating atomization conditions. In one aspect, the invention includes an atomization method for forming a magnet powder comprising: a) forming a melt comprising R.sub.2.1 Q.sub.13.9 B.sub.1, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; b) atomizing the melt to form generally spherical alloy powder granules having an internal structure comprising at least one of a substantially amorphous phase or a substantially nanocrystalline phase; and c) heat treating the alloy powder to increase an energy product of the alloy powder; after the heat treatment, the alloy powder comprising an energy product of at least 10 MGOe. In another aspect, the invention includes a magnet comprising R, Q, B, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; the magnet comprising an internal structure comprising R.sub.2.1 Q.sub.13.9 B.sub.1.

  13. 40 CFR 721.10214 - Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Poly(oxyalkylenediyl),.alpha.-substituted...Specific Chemical Substances § 721.10214 Poly(oxyalkylenediyl),.alpha.-substituted...chemical substance identified generically as...

  14. Advanced NDE Technologies for Powder Metal Components

    SciTech Connect

    Martin, P; Haskins, J; Thomas, G; Dolan, K

    2003-05-01

    Nondestructive evaluation encompasses numerous technologies that assess materials and determine important properties. This paper demonstrates the applicability of several of these technologies to the field of powder metallurgy. The usual application of nondestructive evaluation is to detect and quantify defects in fully sintered product. But probably its most appealing role is to sense problems earlier in the manufacturing process to avoid making defects at all. Also nondestructive evaluation can be incorporated into the manufacturing processes to monitor important parameters and control the processes to produce defect free product. Nondestructive evaluation can characterize powders, evaluate components in the green state, monitor the sintering process, and inspect the final component.

  15. Cleaning process for contaminated superalloy powders

    NASA Technical Reports Server (NTRS)

    Anglin, A. E.

    1978-01-01

    A cleaning process for removing interstitial contaminants from superalloy powders after wet grinding is described. Typical analyses of oxygen, carbon, nitrogen, and hydrogen in ball-milled WAZ-20 superalloy samples after hydrogen plus vacuum cleaning are presented. The hydrogen cleaning step involves heating retorts containing superalloy powder twice under flowing hydrogen with a 24-hour hold at each temperature. The vacuum step involves heating cold-pressed billets two hours at an elevated temperature at a pressure of 10 microPa. It is suggested that the hydrogen plus vacuum cleaning procedure can be applied to superalloys contaminated by other substances in other industrial processes.

  16. Dry powder mixes comprising phase change materials

    DOEpatents

    Salyer, I.O.

    1994-12-06

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft. 3 figures.

  17. Synthesis of ultrafine powders by microwave heating

    DOEpatents

    Meek, T.T.; Sheinberg, H.; Blake, R.D.

    1987-04-24

    A method of synthesizing ultrafine powders using microwaves is described. A water soluble material is dissolved in water and the resulting aqueous solution is exposed to microwaves until the water has dissolved. The resulting material is an ultrafine powder. This method can be used to make Al/sub 2/O/sub 3/, NiO /plus/ Al/sub 2/O/sub 3/ and NiO as well as a number of other materials including GaBa/sub 2/Cu/sub 3/O/sub x/. 1 tab.

  18. Synthesis of ultrafine powders by microwave heating

    DOEpatents

    Meek, Thomas T. (Knoxville, TN); Sheinberg, Haskell (Los Alamos, NM); Blake, Rodger D. (Santa Fe, NM)

    1988-01-01

    A method of synthesizing ultrafine powders using microwaves is described. A water soluble material is dissolved in water and the resulting aqueous solution is exposed to microwaves until the water has been removed. The resulting material is an ultrafine powder. This method can be used to make Al.sub.2 O.sub.3, NiO+Al.sub.2 O.sub.3 and NiO as well as a number of other materials including GaBa.sub.2 Cu.sub.3 O.sub.x.

  19. A mechanistic analysis of bulk powder caking

    NASA Astrophysics Data System (ADS)

    Calvert, G.; Curcic, N.; Ghadiri, M.

    2013-06-01

    Bulk powder transformations, such as caking, can lead to numerous problems within industry when storing or processing materials. In this paper a new Environmental Caking Rig (ECR) is introduced and has been used to evaluate the caking propensity of a hygroscopic powder as a function of temperature, Relative Humidity (RH), mechanical stress and also when RH is cycled. A linear relationship exists between cake strength and the extent of bulk deformation, here defined by the engineering strain. An empirical model has been used to predict the caking behaviour based on consolidation stress and environmental conditions.

  20. The Powder Diffraction File: present and future.

    PubMed

    Faber, John; Fawcett, Tim

    2002-06-01

    The International Centre for Diffraction Data (ICDD) produces the Powder Diffraction File (PDF). This paper discusses some of the seminal events in the history of producing this primary reference for powder diffraction. Recent key events that center on collaborative initiatives have led to an enormous jump in entry population for the PDF. Collective efforts to editorialize the PDF are ongoing and provide enormous added value to the file. Recently, the ICDD has created a new series of the PDF, designated PDF-4. These relational database structures are being used to house the PDF of the future. The design and benefits of the PDF-4 are described. PMID:12037351

  1. Dry powder mixes comprising phase change materials

    DOEpatents

    Salyer, I.O.

    1995-12-26

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft. 3 figs.

  2. Dry powder mixes comprising phase change materials

    DOEpatents

    Salyer, Ival O. (Dayton, OH)

    1995-01-01

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft.

  3. Dry powder mixes comprising phase change materials

    DOEpatents

    Salyer, Ival O. (Dayton, OH)

    1994-01-01

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft.

  4. Synthesis and electrochemical properties of spinel LiCo 1\\/6Mn 11\\/6O 4 powders by a spray-drying method

    Microsoft Academic Search

    W. K. Zhang; C. Wang; H. Huang; Y. P. Gan; H. M. Wu; J. P. Tu

    2008-01-01

    Co-substituted LiCo1\\/6Mn11\\/6O4 powders were prepared by a spray-drying method for positive electrodes of lithium ion batteries. The heat treating process, crystal structure and electrochemical properties of the synthesized materials were investigated by TG\\/DTG, DSC, XRD, SEM, slow rate cyclic voltammetry (CV) and galvanostatic charge\\/discharge cycling tests. The final powders were identified as single-phase spinel LiCo1\\/6Mn11\\/6O4 with high degree of crystallization

  5. Study on the Properties of Fe-substituted NdMn2O5

    NASA Astrophysics Data System (ADS)

    Saravana Kumar, K.; Venkateswaran, C.

    2015-02-01

    The oxide, NdFeMnO5, has been synthesized using a two-step synthesis process. First the precursor oxides are high-energy ball milled and the as-milled powders are then sintered to obtain the NdFeMnO5 phase. X-ray diffraction confirms phase formation and the calculated pattern is obtained by the substitution of Mn3+ sites by Fe3+ sites. Agglomeration of small sized grains is observed from the scanning electron microscopy images. Room temperature magnetization measurement shows a paramagnetic behaviour. A ferrimagnetic ordering is observed to be established below ~110 K from the thermo-magnetization measurements.

  6. Preferential site occupation in Y and La substituted Pr 2Fe 14B intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Moze, O.; Pareti, L.; Marusi, G.; Solzi, M.; David, W. I. F.

    1989-01-01

    The crystal structure of Y and La substituted Pr 2Fe 14B intermetallic compounds has been determined by high resolution neutron time-of-flight powder diffraction. A model which takes into account the rare-earth site occupancies and the measured magnetic anisotropy in Pr 2Fe 14B and Nd 2Fe 14B indicates that the contribution of the 4f site anisotropy to the total axial anisotropy is larger than that of the 4g site in Nd 2Fe 14B compounds. In Pr 2Fe 14B compounds, however, the 4f and 4g site anisotropies are equal.

  7. Magnetic structure of Sn 2+Ru 4+-substituted barium hexaferrites prepared by mechanical alloying

    Microsoft Academic Search

    A. González-Angeles; G. Mendoza-Suárez; A. Grusková; J. Sláma; J. Lipka; M. Papánová

    2005-01-01

    M-type barium hexaferrite fine particles with composition BaFe12?2xSnxRuxO19 (0.0?x?0.3) were obtained by mechanical alloying. The effect of Sn2+–Ru4+ substitution on the magnetic properties and microstructure of the powders was investigated by Mössbauer spectroscopy, XRD, vibrating sample magnetometry (VSM) and thermomagnetic analysis. Mössbauer studies revealed that Sn2+ ions replaced Fe3+ ions on octahedral sites (4f2 and 2a), while Ru4+ preferred the

  8. Non-collinear magnetic order in a Sc-substituted barium hexaferrite

    Microsoft Academic Search

    Z. Somogyvári; E. Sváb; K. Krezhov; L. F. Kiss; D. Kaptás; I. Vincze; E. Beregi; F. Bourèe

    2006-01-01

    A combined magnetic, neutron diffraction and field-dependent 57Fe Mössbauer study of Sc-substituted Ba-hexaferrite in powder form is reported, and the findings are compared with the data for BaFe12O19. The five cation sublattice with collinear ferrimagnetic structure of uniaxial (Gorter) type for BaFe12O19, persists also for BaFe10.4Sc1.6O19 at room temperature and below down to 130–190K, depending on the applied field. Below

  9. Rietveld refinement, electrical properties and magnetic characteristics of Ca-Sr substituted barium hexaferrites

    Microsoft Academic Search

    Ashima Hooda; Sujata Sanghi; Ashish Agarwal; Reetu Dahiya

    M–type Ca-Sr substituted barium hexaferrites having compositions BaFe12O19, Ba0.5Ca0.5Fe12O19 and Ba0.5Ca0.25Sr0.25Fe12O19 have been synthesized by commercial solid state reaction method. The effects of doping on structural, dielectric and magnetic properties were systematically investigated. The Rietveld refinement of X-ray powder diffraction data revealed that the samples possess single hexagonal phase with space group P63\\/mmc, with two molecules in the unit cell

  10. [Bone substitutes - basic principles and clinical applications].

    PubMed

    Garcia, P; Franz, D; Raschke, M

    2014-04-01

    Treatment of bone defects and non-unions frequently requires the transplantation of autologous bone. As an alternative, different kinds of bone substitutes have been used more often during the past years. These bone substitutes include synthetic materials, just as well as processed materials from human donors (allogen) or animals (xenogen). The relatively low hurdles in the approval process, compared to pharmaceutical drugs, have led to an almost unmanageable amount of different kinds of bone substitutes. Due to sparse clinical studies, evidence-based decisions for a specific product or a specific indication are hardly possible. Therefore, a deeper knowledge about basic properties of different bone substitutes is needed for a rational clinical decision. The present review aims to clarify the sometimes confusing nomenclature of bone substitutes and discuss their different biological properties. Generally, bone substitutes can be discriminated in osteogenic, osteoinductive and osteoconductive materials. The great majority of bone substitutes and especially synthetic materials serve as a matrix for bone growth and therefore possess mainly osteoconductive properties. The combination of these osteoconductive materials with osteogenic cells or osteoinductive growth factors, leads to composite materials with higher bone forming potential. Clinically, the quality and vitality of the recipient bone defect is of great importance. As a prerequisite for successful transplantation of bone substitutes or autologous bone, the recipient bone defect should be mechanically stable, free of infection with vital bone ends and intact soft tissue coverage. Bone defects in the spine, methaphyseal defects after trauma/tumour and diaphyseal segmental defects are typical indications for the application of bone substitutes. Unfortunately, the current literature does not allow concrete recommendations for specific bone substitutes or specific clinical indications. However, this review aims to discuss clinical benefits and limitations of bone substitutes for frequent indications to help clinicians in their decision making process. PMID:24760455

  11. Electromagnetic properties of samarium-substituted NiCuZn ferrite prepared by auto-combustion method

    NASA Astrophysics Data System (ADS)

    Roy, P. K.; Bera, J.

    2009-02-01

    Ni 0.25Cu 0.2Zn 0.55Sm xFe 2-xO 4 ferrite with x=0.00, 0.025, 0.05 and 0.075 compositions were synthesized through the nitrate-citrate auto-combustion method. These powders were calcined, compacted and sintered at 900 °C for 4 h. Effect of Sm substitution on phase composition, microstructure and relative density were studied. Permeability, magnetic loss and AC resistivity were measured in the frequency range of 1 kHz-10 MHz. Permeability and AC resistivity were found to increase and loss decreased with Sm substitution up to x=0.05. Saturation magnetization also increased up to that substitution limit. Observed variations in electromagnetic properties have been explained.

  12. The development of an alternative thermoplastic powder prepregging technique

    NASA Technical Reports Server (NTRS)

    Ogden, A. L.; Hyer, M. W.; Muellerleile, J. T.; Wilkes, G. L.; Loos, A. C.

    1990-01-01

    Discussed is a novel powder prepregging technique that is based on the deposition of the powder onto fibers that have been moistened using an ultrasonic humidifier. The moisture acts as an initial binding agent for the powder until the powder can be melted onto the fiber in a subsequent heating step. LaRC-TPI powder, produced by Mitsui Toastsu, and Hercules AS-4 fiber served as the process development material system. The influence of powder particle size on this process, and the quality of the resulting composite are discussed.

  13. The Effect of Te Substitution for Sb on Thermoelectric Properties of Tetrahedrite

    NASA Astrophysics Data System (ADS)

    Lu, Xu; Morelli, Donald

    2014-06-01

    We present the study of the effect of Te substitution on the thermoelectric properties for Sb in Cu12Sb4- x Te x S13 tetrahedrite compounds with x ranging from 0.2 to 1.5 in the temperature range of room temperature to 723 K. Powder x-ray diffraction and electron microscopy results indicate a successful homogenous substitution without the alteration of the crystal structure or the introduction of secondary phases. Thermoelectric property measurements show that the excess electrons from Te during the substitution fill the unoccupied levels near the top of the valence bands in pure Cu12Sb4S13 compound, moving the Fermi level closer to the top of the valence bands. This leads to an enhancement in thermopower but also to an increase in electrical resistivity. Overall, the reduction in total thermal conductivity gives rise to improved ZT values in all substituted samples. The highest ZT value obtained in this study is 0.92 at 723 K for x = 1, which is comparable to that of other p-type bulk thermoelectric materials.

  14. Stratigraphy and depositional environments of middle member of Minnelusa formation, central Powder River basin, Wyoming

    SciTech Connect

    Desmond, R.J.; Steidtmann, J.R.; Cardinal, D.F.

    1985-05-01

    Regional correlations, from the southern to northern Black Hills and across the central Powder River basin to the Bighorn Mountains, serve as the frame work for a depositional model of middle Minnelusa sediments. In the eastern part of the study area, deposition took place in a carbonate sabkha environment. During transgressive periods, most of this region was covered by a restricted shallow sea. In the northern Black Hills, close to the limit of the transgression, deposition occurred in a coastal dune setting. During regressions, the sabkha prograded westward toward the Lusk embayment. Coastal dune fields to the north and isolated dune complexes to the south migrated southwestward across this prograding sabkha. West of the Lusk embayment, deposition occurred in a sand dominated tidal-flat environment during transgressions and along the coastal edge of an eolian sand sea during regression.

  15. Substitute Teachers as Effective Classroom Instructors

    ERIC Educational Resources Information Center

    Glatfelter, Andrew Gary

    2006-01-01

    Over the course of their kindergarten through twelfth grade education, children in American public schools will spend the equivalent of one school year under the guidance of a substitute teacher. Yet in most districts, substitutes are given the keys to the classroom without a day's training. While requirements vary by state, some may hold advanced…

  16. Substitute Your Way to a Real Job

    ERIC Educational Resources Information Center

    Stephens, Cathy

    2013-01-01

    For some, substitute teaching is a career choice. However, for the majority of new teachers, it is often a necessary gateway to landing a first job. Either way, it is a great way to sharpen one's skills. This article presents tips from principals, teachers, and human resource directors to make the most of the substitute teaching experience…

  17. Multisensory integration, sensory substitution and visual rehabilitation.

    PubMed

    Proulx, Michael J; Ptito, Maurice; Amedi, Amir

    2014-04-01

    Sensory substitution has advanced remarkably over the past 35 years since first introduced to the scientific literature by Paul Bach-y-Rita. In this issue dedicated to his memory, we describe a collection of reviews that assess the current state of neuroscience research on sensory substitution, visual rehabilitation, and multisensory processes. PMID:24759484

  18. Amino acid substitution matrices from protein blocks

    Microsoft Academic Search

    Steven Henikoff; Jorja G. Henikoff

    1992-01-01

    Methods for alignment of protein sequences typically measure similarity by using a substitution matrix with scores for all possible exchanges of one amino acid with another. The most widely used matrices are based on the Dayhoff model of evolutionary rates. Using a different approach, we have derived substitution matrices from about 2000 blocks of aligned sequence segments characterizing more than

  19. Carboranylmethylene-substituted phosphazenes and polymers thereof

    NASA Technical Reports Server (NTRS)

    Allcock, H. R.; Scopelianos, A. G. (inventors)

    1984-01-01

    Carboranylmethylene-substituted cyclophosphazenes are described which can be thermally polymerized into carboranylmethylene-substituted phosphazene polymers. The polymers are useful as thermally stable coatings. Also, due to the characteristics of these polymers in acting as a ligand for transition metals, metalocarboranylmethylene phosphazene polymers are described which can act as immobilized catalyst systems, and are electrically conductive and superconductive.

  20. Pitfalls in Designing Substitution Boxes (Extended Abstract)

    E-print Network

    Zheng, Yuliang

    Pitfalls in Designing Substitution Boxes (Extended Abstract) Jennifer Seberry, Xian-Mo Zhang S-boxes or substitution boxes so that an encryption algorithm that em- ploys the S-boxes is immune. The Hamming weight of a vector 2 Vn, denoted by W( ), is the number of ones in the vector. #12;A (1 ;1)-matrix

  1. SIMILARITY NETWORK FOR SEMANTIC WEB SERVICES SUBSTITUTION

    E-print Network

    Paris-Sud XI, Université de

    SIMILARITY NETWORK FOR SEMANTIC WEB SERVICES SUBSTITUTION Chantal Cherifi LE2I Laboratory, Burgundy is performed on a benchmark of semantically annotated Web services. Results show that this approach allows a more detailed analysis of substitutable Web services. Keywords - Semantic Web services, Functional

  2. Powder River 0 20 40 KILOMETERS

    E-print Network

    WYOMING MONTANA Powder River Basin 0 20 40 KILOMETERS 0 20 40 MILES 44° 45° 46° 43° 107° 106° 105° Gillette Miles City Birney Sheridan Buffalo Glenrock Glenrock Douglas Moorcroft Decker Colstrip Ashland Forsyth Lame Deer Broadus MONTANA WYOMING MONTANA WYOMING TREASURE COUNTY ROSEBUD COUNTY CARTER COUNTY

  3. Evaluation of powder metallurgy superalloy disk materials

    NASA Technical Reports Server (NTRS)

    Evans, D. J.

    1975-01-01

    A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

  4. Strength enhancement process for prealloyed powder superalloys

    NASA Technical Reports Server (NTRS)

    Waters, W. J.; Freche, J. C.

    1977-01-01

    A technique involving superplastic processing and high pressure autoclaving was applied to a nickel base prealloyed powder alloy. Tensile strengths as high as 2865 MN/sq m at 480 C were obtained with as-superplastically deformed material. Appropriate treatments yielding materials with high temperature tensile and stress rupture strengths were also devised.

  5. Preparation and properties of composite mineral powders

    Microsoft Academic Search

    Guo-Sheng Gai; Yu-Fen Yang; Shi-Min Fan; Zhen-Fang Cai

    2005-01-01

    Mineral powders such as ground calcium carbonate (GCC) and wollastonite are widely used as fillers in plastics, rubber, paper, paints and other fields. The interface compatibility between the polymer matrix and the mineral particles is relatively weak, both because of the smooth cleavage surface and the sharp particle edges formed during pulverizing. It is beneficial therefore to modify the surface

  6. Ceramic powder synthesis by spray pyrolysis

    Microsoft Academic Search

    Gary L. Messing; Shi-Chang Zhang; Gopal V. Jayanthi

    1993-01-01

    A variety of spray pyrolysis (SP) techniques have been developed to directly produce ceramic powders from solutions. This paper reviews the current status of these processes in terms of the process parameters that enable the formation of particles with controlled morphology and composition. A model incorporating solute diffusion in the droplet and solvent evaporation from the droplet surface is presented

  7. USING POWDERED ACTIVATED CARBON: A CRITICAL REVIEW

    EPA Science Inventory

    Because the performance of powdered activated carbon (PAC) for uses other than taste and odor control is poorly documented, the purpose of this article is to critically review uses that have been reported and to analyze means of employing PAC more efficiently. The extent of adsor...

  8. USING POWDERED ACTIVATED CARBON: A CRITICAL REVIEW

    EPA Science Inventory

    Because the performance of powdered activated carbon (PAC) for uses other than taste and odor control is poorly documented, the purpose of this article is to critically review uses that have been reported (i.e., pesticides and herbicides, synthetic organic chemicals, and trihalom...

  9. Screening mail for powders using terahertz technology

    NASA Astrophysics Data System (ADS)

    Kemp, Mike

    2011-11-01

    Following the 2001 Anthrax letter attacks in the USA, there has been a continuing interest in techniques that can detect or identify so-called 'white powder' concealed in envelopes. Electromagnetic waves (wavelengths 100-500 ?m) in the terahertz frequency range penetrate paper and have short enough wavelengths to provide good resolution images; some materials also have spectroscopic signatures in the terahertz region. We report on an experimental study into the use of terahertz imaging and spectroscopy for mail screening. Spectroscopic signatures of target powders were measured and, using a specially designed test rig, a number of imaging methods based on reflection, transmission and scattering were investigated. It was found that, contrary to some previous reports, bacterial spores do not appear to have any strong spectroscopic signatures which would enable them to be identified. Imaging techniques based on reflection imaging and scattering are ineffective in this application, due to the similarities in optical properties between powders of interest and paper. However, transmission imaging using time-of-flight of terahertz pulses was found to be a very simple and sensitive method of detecting small quantities (25 mg) of powder, even in quite thick envelopes. An initial feasibility study indicates that this method could be used as the basis of a practical mail screening system.

  10. Sol-Gel Synthesis Of Aluminoborosilicate Powders

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey; Leiser, Daniel; Selvaduray, Guna

    1992-01-01

    Application of sol-gel process to synthesis of aluminoborosilicate powders shows potential for control of microstructures of materials. Development of materials having enhanced processing characteristics prove advantageous in extending high-temperature endurance of fibrous refractory composite insulation made from ceramic fibers.

  11. Characterization of nal powders for rocket propulsion

    NASA Astrophysics Data System (ADS)

    Merotto, L.; Galfetti, L.; Colombo, G.; DeLuca, L. T.

    2011-10-01

    Nanosized metal powders are known to significantly improve both solid and hybrid rocket performance, but have some drawbacks in terms of cost, safety, and possible influence on propellant mechanical properties. Performance enhancement through nanosized metal or metal hydride addition to solid fuels is currently under investigation also for hybrid propulsion. Therefore, a preburning characterization of the powders used in solid propellant or fuel manufacturing is useful to assess their effects on the ballistic properties and engine performance. An investigation concerning the comparative characterization of several aluminum powders having different particle size, age, and coating is presented. Surface area, morphology, chemical species concentration and characteristics, surface passivation layers, surface and subsurface chemical composition, ignition temperature and ignition delay are investigated. The aim of this characterization is to experimentally assess the effect of the nAl powder properties on ballistic characteristics of solid fuels and solidrocket composite-propellant performance, showing an increase in terms of Is caused by the decrease of two-phase losses in solid and a possible significant rf increase in hybrid rockets.

  12. Ripples in Tapped or Blown Powder

    Microsoft Academic Search

    Jacques Duran; M. Curie

    2000-01-01

    We observe ripples forming on the surface of a granular powder in a container submitted from below to a series of brief and distinct shocks. After a few taps, the pattern turns out to be stable against any further shock of the same amplitude. We find that the wavelength of the pattern is proportional to the amplitude of the shocks.

  13. Macromolecular powder diffraction : structure solution via molecular.

    SciTech Connect

    Doebbler, J.; Von Dreele, R.; X-Ray Science Division

    2009-01-01

    Macromolecular powder diffraction is a burgeoning technique for protein structure solution - ideally suited for cases where no suitable single crystals are available. Over the past seven years, pioneering work by Von Dreele et al. [1,2] and Margiolaki et al. [3,4] has demonstrated the viability of this approach for several protein structures. Among these initial powder studies, molecular replacement solutions of insulin and turkey lysozyme into alternate space groups were accomplished. Pressing the technique further, Margiolaki et al. [5] executed the first molecular replacement of an unknown protein structure: the SH3 domain of ponsin, using data from a multianalyzer diffractometer. To demonstrate that cross-species molecular replacement using image plate data is also possible, we present the solution of hen egg white lysozyme using the 60% identical human lysozyme (PDB code: 1LZ1) as the search model. Due to the high incidence of overlaps in powder patterns, especially in more complex structures, we have used extracted intensities from five data sets taken at different salt concentrations in a multi-pattern Pawley refinement. The use of image plates severely increases the overlap problem due to lower detector resolution, but radiation damage effects are minimized with shorter exposure times and the fact that the entire pattern is obtained in a single exposure. This image plate solution establishes the robustness of powder molecular replacement resulting from different data collection techniques.

  14. Triboelectrification of pharmaceutical powders by particle impact.

    PubMed

    Watanabe, Hideo; Ghadiri, Mojtaba; Matsuyama, Tatsushi; Ding, Yu Long; Pitt, Kendal G; Maruyama, Hiroyuki; Matsusaka, Shuji; Masuda, Hiroaki

    2007-04-01

    Pharmaceutical powders are very prone to electrostatic charging by colliding and sliding contacts with walls and other particles. In pharmaceutical formulation processes, particle charging is often a nuisance and can cause problems in the manufacture of products, such as affecting powder flow, and reducing fill and dose uniformity. For a fundamental understanding of the powder triboelectrification, it is essential to study charge transfer due to a single contact of a particle with a target plane under well-defined physical, mechanical and electrical conditions. In this study, charge transfer due to a single impact of a particle against a stainless steel target was measured for alpha-lactose monohydrate, aspirin, sugar granules and ethylcellulose. The amount of transferred charge is expressed as a function of impact velocity and impact angle as well as the initial charge. The maximum contact area during impact between a particle and a target plane is estimated by an elastic-plastic deformation model. It is found that the transferred charge is a linear function of the contact area. For a given material, there is an initial particle charge for which no charge transfer occurs due to impact. This is found to be independent of impact velocity and angle, and is hence viewed as a characteristic property, which is related to the contact potential difference and tribo-electric series of the sample powders. PMID:17141989

  15. Balanced mechanical resonator for powder handling device

    NASA Technical Reports Server (NTRS)

    Sarrazin, Philippe C. (Inventor); Brunner, Will M. (Inventor)

    2012-01-01

    A system incorporating a balanced mechanical resonator and a method for vibration of a sample composed of granular material to generate motion of a powder sample inside the sample holder for obtaining improved analysis statistics, without imparting vibration to the sample holder support.

  16. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    EPA Science Inventory

    The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

  17. Laboratory Powder Metallurgy Makes Tough Aluminum Sheet

    NASA Technical Reports Server (NTRS)

    Royster, D. M.; Thomas, J. R.; Singleton, O. R.

    1993-01-01

    Aluminum alloy sheet exhibits high tensile and Kahn tear strengths. Rapid solidification of aluminum alloys in powder form and subsequent consolidation and fabrication processes used to tailor parts made of these alloys to satisfy such specific aerospace design requirements as high strength and toughness.

  18. Triboelectric charging of powders: A review

    Microsoft Academic Search

    S. Matsusaka; H. Maruyama; T. Matsuyama; M. Ghadiri

    2010-01-01

    Particles are often electrostatically charged by frictional contact during powder-handling operations. This phenomenon is called ‘triboelectric charging’ or ‘contact electrification’. The charged particles cause problems such as particle deposition and adhesion. In addition, if particles are excessively charged, an electrostatic discharge may occur, which can pose a risk of fire and explosion hazards; thus, to mitigate the adverse effects, it

  19. Calcium phosphate cement - gelatin powder composite testing in canine models: Clinical implications for treatment of bone defects.

    PubMed

    Yomoda, Mitsuhiro; Sobajima, Satoshi; Kasuya, Akihiro; Neo, Masashi

    2015-05-01

    Previous studies have reported the excellent biocompatibility of calcium phosphate cement. However, calcium phosphate cement needs further improvement in order for it to promote bone replacement and eventual bone substitution, as it exhibits slow biodegradability and thus remains in the body over an extended period of time. In this study, we mixed calcium phosphate cement with gelatin powder in order to create a composite containing macropores with interconnectivity, and we then implanted it into canine femurs from the diaphysis to the distal metaphysis. Eight dogs were divided into the sham group, the control (C0) group with 100 wt% calcium phosphate cement, the C10 group with 90 wt% calcium phosphate cement and 10 wt% gelatin powder, and the C15 group with 85 wt% calcium phosphate cement and 15 wt% gelatin powder. Bone replaceability in C10 and C15 at 3 and 6 months was evaluated by radiography, micro-CT, histomorphometry, and mineral apposition rate. New bone formation was seen in C10 and C15 although that was not seen in C0 at six months. The mineral apposition rate was significantly higher in C15 than in C10 in both the diaphysis and metaphysis, and the composite was found to have excellent biodegradability and bone replaceability in canine subjects. As the composite is easily and rapidly prepared, it is likely to become a new bone substitute for use in clinical settings. PMID:25550332

  20. Improved Small-Particle Powders for Plasma Spraying

    NASA Technical Reports Server (NTRS)

    Nguyen, QuynhGiao, N.; Miller, Robert A.; Leissler, George W.

    2005-01-01

    Improved small-particle powders and powder-processing conditions have been developed for use in plasma spray deposition of thermal-barrier and environmental barrier coatings. Heretofore, plasma-sprayed coatings have typically ranged in thickness from 125 to 1,800 micrometers. As explained below, the improved powders make it possible to ensure complete coverage of substrates at unprecedently small thicknesses of the order of 25 micrometers. Plasma spraying involves feeding a powder into a hot, high-velocity plasma jet. The individual powder particles melt in the plasma jet as they are propelled towards a substrate, upon which they splat to build up a coating. In some cases, multiple coating layers are required. The size range of the powder particles necessarily dictates the minimum thickness of a coating layer needed to obtain uniform or complete coverage. Heretofore, powder particle sizes have typically ranged from 40 to 70 micrometers; as a result, the minimum thickness of a coating layer for complete coverage has been about 75 micrometers. In some applications, thinner coatings or thinner coating layers are desirable. In principle, one can reduce the minimum complete-coverage thickness of a layer by using smaller powder particles. However, until now, when powder particle sizes have been reduced, the powders have exhibited a tendency to cake, clogging powder feeder mechanisms and feed lines. Hence, the main problem is one of synthesizing smaller-particle powders having desirable flow properties. The problem is solved by use of a process that begins with a spray-drying subprocess to produce spherical powder particles having diameters of less than 30 micrometers. (Spherical-particle powders have the best flow properties.) The powder is then passed several times through a commercial sifter with a mesh to separate particles having diameters less than 15 micrometers. The resulting fine, flowable powder is passed through a commercial fluidized bed powder feeder into a plasma spray jet.

  1. Quantum Black Holes. Black Hole Temperature without a Black Hole

    E-print Network

    Victor Berezin

    2008-12-24

    The model is constructed, some features of which comes from quantum thin dust shells and is, in fact, an extension of the "no hair" property of classical black hole on a quantum level. It appears that the proposed classical analog of quantum black hole is heated, the temperature being exactly the Hawking's temperature.

  2. Surface dose measurement using TLD powder extrapolation

    SciTech Connect

    Rapley, P. [Regional Cancer Care, Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario (Canada)]. E-mail: rapleyp@tbh.net

    2006-10-01

    Surface/near-surface dose measurements in therapeutic x-ray beams are important in determining the dose to the dermal and epidermal skin layers during radiation treatment. Accurate determination of the surface dose is a difficult but important task for proper treatment of patients. A new method of measuring surface dose in phantom through extrapolation of readings from various thicknesses of thermoluminescent dosimeter (TLD) powder has been developed and investigated. A device was designed, built, and tested that provides TLD powder thickness variation to a minimum thickness of 0.125 mm. Variations of the technique have been evaluated to optimize precision with consideration of procedural ease. Results of this study indicate that dose measurements (relative to D{sub max}) in regions of steep dose gradient in the beam axis direction are possible with a precision (2 standard deviations [SDs]) as good as {+-} 1.2% using the technique. The dosimeter was developed and evaluated using variation to the experimental method. A clinically practical procedure was determined, resulting in measured surface dose of 20.4 {+-} 2% of the D{sub max} dose for a 10 x 10 cm{sup 2}, 80-cm source-to-surface distance (SSD), Theratron 780 Cobalt-60 ({sup 60}C) beam. Results obtained with TLD powder extrapolation compare favorably to other methods presented in the literature. The TLD powder extrapolation tool has been used clinically at the Northwestern Ontario Regional Cancer Centre (NWORCC) to measure surface dose effects under a number of conditions. Results from these measurements are reported. The method appears to be a simple and economical tool for surface dose measurement, particularly for facilities with TLD powder measurement capabilities.

  3. Conservation of Neutral Substitution Rate and Substitutional Asymmetries in Mammalian Genes

    PubMed Central

    Mugal, C.F.; Wolf, J.B.W.; von Grünberg, H.H.; Ellegren, H.

    2010-01-01

    Local variation in neutral substitution rate across mammalian genomes is governed by several factors, including sequence context variables and structural variables. In addition, the interplay of replication and transcription, known to induce a strand bias in mutation rate, gives rise to variation in substitutional strand asymmetries. Here, we address the conservation of variation in mutation rate and substitutional strand asymmetries using primate- and rodent-specific repeat elements located within the introns of protein-coding genes. We find significant but weak conservation of local mutation rates between human and mouse orthologs. Likewise, substitutional strand asymmetries are conserved between human and mouse, where substitution rate asymmetries show a higher degree of conservation than mutation rate. Moreover, we provide evidence that replication and transcription are correlated to the strength of substitutional asymmetries. The effect of transcription is particularly visible for genes with highly conserved gene expression. In comparison with replication and transcription, mutation rate influences the strength of substitutional asymmetries only marginally. PMID:20333222

  4. 40 CFR 721.10626 - 1,4-Butanediol, polymer with substituted alkane and substituted methylene biscarbomonocycle, 2...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false 1,4-Butanediol, polymer with substituted alkane and substituted... § 721.10626 1,4-Butanediol, polymer with substituted alkane and substituted...identified generically as 1,4-butanediol, polymer with substituted alkane and...

  5. 40 CFR 721.10626 - 1,4-Butanediol, polymer with substituted alkane and substituted methylene biscarbomonocycle, 2...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false 1,4-Butanediol, polymer with substituted alkane and substituted... § 721.10626 1,4-Butanediol, polymer with substituted alkane and substituted...identified generically as 1,4-butanediol, polymer with substituted alkane and...

  6. Characterization and Control of Powder Properties for Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Strondl, A.; Lyckfeldt, O.; Brodin, H.; Ackelid, U.

    2015-03-01

    Powder characterization and handling in powder metallurgy are important issues and the required powder properties will vary between different component manufacturing processes. By understanding and controlling these, the final material properties for different applications can be improved and become more reliable. In this study, the metal powders used in additive manufacturing (AM) in terms of electron beam melting and selective laser melting have been investigated regarding particle size and shape using dynamic image analysis. In parallel, powder flow characteristics have been evaluated with a powder rheometer. Correlations within the results have been found between particle shape and powder flow characteristics that could explain certain effects of the powder processing in the AM processes. The impact, however, in the processing performance as well as in ultimate material properties was found to be limited.

  7. Veratrum alkaloids in sneezing-powder a potential danger.

    PubMed

    Fogh, A; Kulling, P; Wickstrom, E

    1983-04-01

    Sneezing-powders containing pulverized root of veratrum album (white hellebore) have recently been marketed in the Scandinavian countries. The powder, imported from the Federal Republic of Germany, has caused severe intoxications. PMID:6887310

  8. Study of Velocity and Materials on Tribocharging of Polymer Powders for Powder Coating Applications

    NASA Technical Reports Server (NTRS)

    Biris, Alex S.; Trigwell, Steve; Sims, Robert A.; Mazumder, Malay K.

    2005-01-01

    Electrostatic powder deposition is widely used in a plethora of industrial-applications ranging from the pharmaceutical and food.industries, to farm equipment and automotive applications. The disadvantages of this technique are possible back corona (pin-like formations) onset and the Faraday penetration limitation (when the powder does not penetrate in some recessed areas). A possible solution to overcome these problems is to use tribochargers to electrostatically charge the powder. Tribocharging, or contact charging while two materials are in contact, is related to the work function difference between the contacting materials and generates bipolarly charged particles. The generation of an ion-free powder cloud by tribocharging with high bipolar charge and an overall charge density of almost zero, provides a better coverage of the recessed areas. In this study, acrylic and epoxy powders were fluidized and charged by passing through stainless steel, copper, aluminum, and polycarbonate static mixers, respectively. The particle velocity was varied to determine its effect on the net charge-to-mass ratio (QIM) acquired by the powders. In general, the Q/M increases rapidly when the velocity was increased from 1.5 to 2.5 m/s, remaining almost constant for higher velocities. Charge separation experiments showed bipolar charging for all chargers.

  9. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). 721.7255...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). (a) Chemical...polyethyleneamine crosslinked with substituted polyethylene glycol with substituted...

  10. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). 721.7255...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). (a) Chemical...polyethyleneamine crosslinked with substituted polyethylene glycol with substituted...

  11. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). 721.7255...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). (a) Chemical...polyethyleneamine crosslinked with substituted polyethylene glycol with substituted...

  12. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). 721.7255...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). (a) Chemical...polyethyleneamine crosslinked with substituted polyethylene glycol with substituted...

  13. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). 721.7255...Polyethyleneamine crosslinked with substituted polyethylene glycol (generic). (a) Chemical...polyethyleneamine crosslinked with substituted polyethylene glycol with substituted...

  14. 40 CFR 721.10048 - Substituted anthraquinone (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Substituted anthraquinone (generic). 721.10048 Section...Substances § 721.10048 Substituted anthraquinone (generic). (a) Chemical substance...identified generically as substituted anthraquinone (PMN P-02-869) is subject...

  15. 40 CFR 721.10048 - Substituted anthraquinone (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Substituted anthraquinone (generic). 721.10048 Section...Substances § 721.10048 Substituted anthraquinone (generic). (a) Chemical substance...identified generically as substituted anthraquinone (PMN P-02-869) is subject...

  16. 40 CFR 721.10048 - Substituted anthraquinone (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Substituted anthraquinone (generic). 721.10048 Section...Substances § 721.10048 Substituted anthraquinone (generic). (a) Chemical substance...identified generically as substituted anthraquinone (PMN P-02-869) is subject...

  17. 40 CFR 721.10048 - Substituted anthraquinone (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Substituted anthraquinone (generic). 721.10048 Section...Substances § 721.10048 Substituted anthraquinone (generic). (a) Chemical substance...identified generically as substituted anthraquinone (PMN P-02-869) is subject...

  18. 40 CFR 721.10048 - Substituted anthraquinone (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Substituted anthraquinone (generic). 721.10048 Section...Substances § 721.10048 Substituted anthraquinone (generic). (a) Chemical substance...identified generically as substituted anthraquinone (PMN P-02-869) is subject...

  19. 40 CFR 721.4596 - Diazo substituted carbomonocyclic metal complex.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...false Diazo substituted carbomonocyclic metal complex. 721.4596 Section 721...4596 Diazo substituted carbomonocyclic metal complex. (a) Chemical substance and...generically as a diazo substituted carbomonocyclic metal complex (PMN P-94-1039) is...

  20. 40 CFR 721.5278 - Substituted naphthalenesulfonic acid, alkali salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Substituted naphthalenesulfonic acid, alkali salt. 721.5278 Section 721.5278 ...Substituted naphthalenesulfonic acid, alkali salt. (a) Chemical substance and significant...substituted naphthalenesulfonic acid, alkali salt (PMN P-95-85) is subject to...

  1. 40 CFR 721.3565 - Ethylenediamine, substituted, sodium salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Ethylenediamine, substituted, sodium salt. 721.3565 Section 721.3565 ...Ethylenediamine, substituted, sodium salt. (a) Chemical substance and significant...as ethylenediamine, substituted, sodium salt (PMN P-97-328) is subject to...

  2. 40 CFR 721.8900 - Substituted halogenated pyridinol, alkali salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Substituted halogenated pyridinol, alkali salt. 721.8900 Section 721.8900 ...Substituted halogenated pyridinol, alkali salt. (a) Chemical substances and significant...substituted halogenated pyridinols, alkali salts (PMNs P-88-1271 and...

  3. 40 CFR 721.640 - Amine substituted metal salts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Amine substituted metal salts. 721.640 Section 721.640 Protection... § 721.640 Amine substituted metal salts. (a) Chemical substance and significant...identified generically as amine substituted metal salts (PMNs...

  4. 40 CFR 721.5278 - Substituted naphthalenesulfonic acid, alkali salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Substituted naphthalenesulfonic acid, alkali salt. 721.5278 Section 721.5278 ...Substituted naphthalenesulfonic acid, alkali salt. (a) Chemical substance and significant...substituted naphthalenesulfonic acid, alkali salt (PMN P-95-85) is subject to...

  5. 40 CFR 721.8900 - Substituted halogenated pyridinol, alkali salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Substituted halogenated pyridinol, alkali salt. 721.8900 Section 721.8900 ...Substituted halogenated pyridinol, alkali salt. (a) Chemical substances and significant...substituted halogenated pyridinols, alkali salts (PMNs P-88-1271 and...

  6. 40 CFR 721.843 - Substituted phenylazophenylazo phenol (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false Substituted phenylazophenylazo phenol (generic). 721.843 Section 721...843 Substituted phenylazophenylazo phenol (generic). (a) Chemical substance...generically as substituted phenylazophenylazo, phenol (PMN P-00-0420) is subject...

  7. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Substituted phosphate ester (generic). 721.3080 Section...Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical...identified generically as a substituted phosphate ester (PMN P-85-730) is...

  8. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Substituted phosphate ester (generic). 721.3080 Section...Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical...identified generically as a substituted phosphate ester (PMN P-85-730) is...

  9. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Substituted phosphate ester (generic). 721.3080 Section...Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical...identified generically as a substituted phosphate ester (PMN P-85-730) is...

  10. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Substituted phosphate ester (generic). 721.3080 Section...Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical...identified generically as a substituted phosphate ester (PMN P-85-730) is...

  11. 40 CFR 721.3080 - Substituted phosphate ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false Substituted phosphate ester (generic). 721.3080 Section...Substances § 721.3080 Substituted phosphate ester (generic). (a) Chemical...identified generically as a substituted phosphate ester (PMN P-85-730) is...

  12. 40 CFR 721.1760 - Substituted benzotriazole derivatives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... false Substituted benzotriazole derivatives. 721.1760 Section 721.1760...721.1760 Substituted benzotriazole derivatives. (a) Chemical substances and significant...generically as substituted benzotriazole derivatives (PMNs P-93-374 and...

  13. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Substituted phenylimino carbamate derivative. 721.2025 Section 721.2025... Substituted phenylimino carbamate derivative. (a) Chemical substance and significant...as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject...

  14. 40 CFR 721.1760 - Substituted benzotriazole derivatives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... false Substituted benzotriazole derivatives. 721.1760 Section 721.1760...721.1760 Substituted benzotriazole derivatives. (a) Chemical substances and significant...generically as substituted benzotriazole derivatives (PMNs P-93-374 and...

  15. 40 CFR 721.1760 - Substituted benzotriazole derivatives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Substituted benzotriazole derivatives. 721.1760 Section 721.1760...721.1760 Substituted benzotriazole derivatives. (a) Chemical substances and significant...generically as substituted benzotriazole derivatives (PMNs P-93-374 and...

  16. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Substituted phenylimino carbamate derivative. 721.2025 Section 721.2025... Substituted phenylimino carbamate derivative. (a) Chemical substance and significant...as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject...

  17. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Substituted phenylimino carbamate derivative. 721.2025 Section 721.2025... Substituted phenylimino carbamate derivative. (a) Chemical substance and significant...as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject...

  18. 40 CFR 721.1760 - Substituted benzotriazole derivatives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Substituted benzotriazole derivatives. 721.1760 Section 721.1760...721.1760 Substituted benzotriazole derivatives. (a) Chemical substances and significant...generically as substituted benzotriazole derivatives (PMNs P-93-374 and...

  19. 40 CFR 721.2025 - Substituted phenylimino carbamate derivative.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Substituted phenylimino carbamate derivative. 721.2025 Section 721.2025... Substituted phenylimino carbamate derivative. (a) Chemical substance and significant...as a substituted phenylimino carbamate derivative (PMN P-91-487) is subject...

  20. 12 CFR 229.52 - Substitute check warranties.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Substitute check warranties. 229.52 Section 229.52 ...SYSTEM AVAILABILITY OF FUNDS AND COLLECTION OF CHECKS (REGULATION CC) Substitute Checks § 229.52 Substitute check...