Science.gov

Sample records for kurtz powder technique

  1. Exploratory Activity in Drosophila Requires the kurtz Nonvisual Arrestin

    PubMed Central

    Liu, Lingzhi; Davis, Ronald L.; Roman, Gregg

    2007-01-01

    When Drosophila adults are placed into an open field arena, they initially exhibit an elevated level of activity followed by a reduced stable level of spontaneous activity. We have found that the initial elevated component arises from the fly's interaction with the novel arena since: (1) the increased activity is independent of handling prior to placement within the arena, (2) the fly's elevated activity is proportional to the size of the arena, and (3) the decay in activity to spontaneous levels requires both visual and olfactory input. These data indicate that active exploration is the major component of elevated initial activity. There is a specific requirement for the kurtz nonvisual arrestin in the nervous system for both the exploration stimulated by the novel arena and the mechanically stimulated activity. kurtz is not required for spontaneous activity; kurtz mutants display normal levels of spontaneous activity and average the same velocities as wild-type controls. Inhibition of dopamine signaling has no effect on the elevated initial activity phase in either wild-type or krz1 mutants. Therefore, the exploratory phase of open field activity requires kurtz in the nervous system, but is independent of dopamine's stimulation of activity. PMID:17151232

  2. Densification of powder metallurgy billets by a roll consolidation technique

    NASA Technical Reports Server (NTRS)

    Sellman, W. H.; Weinberger, W. R.

    1973-01-01

    Container design is used to convert partially densified powder metallurgy compacts into fully densified slabs in one processing step. Technique improves product yield, lowers costs and yields great flexibility in process scale-up. Technique is applicable to all types of fabricable metallic materials that are produced from powder metallurgy process.

  3. Physical and chemical characterization techniques for metallic powders

    SciTech Connect

    Slotwinski, J. A.; Stutzman, P. E.; Ferraris, C. F.; Watson, S. S.; Peltz, M. A.; Garboczi, E. J.

    2014-02-18

    Systematic studies have been carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. An extensive array of characterization techniques were applied to these two powders. The physical techniques included laser-diffraction particle-size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to chemistry included X-ray diffraction and energy-dispersive analytical X-ray analysis. The background of these techniques will be summarized and some typical findings comparing different samples of virgin additive manufacturing powders, taken from the same lot, will be given. The techniques were used to confirm that different samples of powder from the same lot were essentially identical, within the uncertainty of the measurements.

  4. Improvement of stability and absorbability of dry insulin powder for inhalation by powder-combination technique.

    PubMed

    Todo, Hiroaki; Okamoto, Hirokazu; Iida, Kotaro; Danjo, Kazumi

    2004-03-01

    The effect of pulmonary absorption enhancers on the stability of active ingredients is an important factor for successful inhalation therapy as well as the effect on pharmacological activity and safety. We examined the effect of pulmonary absorption enhancers on the stability of insulin in dry powders prepared by a spray-drying technique. Although the hypoglycemic effect was greatly improved when a dry insulin powder containing citric acid (MIC SD) was administered, insulin in the MIC SD was unstable compared with the other powders examined. Bacitracin and Span 85, which are potent pulmonary absorption enhancers of insulin formulated in solutions, showed no deteriorative effect on the stability of dry insulin powder. However, they did not improve the hypoglycemic effect of insulin in dry powders. We modified the insulin dosage form with citric acid to improve the insulin stability at room temperature without loss of hypoglycemic activity. MIC Mix was formulated as a combination of insulin powder (MI') and citric acid powder (MC). MIC Mix showed hypoglycemic activity comparable to MIC SD while the insulin stability was much better than that of MIC SD at a 60 degrees C/dry condition. However, moisture lowered the insulin stability and changed the particle morphology of MIC Mix with time at a 60 degrees C/75% relative humidity condition, suggesting that a package preventing moisture absorption was necessary for the MIC Mix powder. PMID:15129972

  5. Application of physical and chemical characterization techniques to metallic powders

    SciTech Connect

    Slotwinski, J. A.; Watson, S. S.; Stutzman, P. E.; Ferraris, C. F.; Peltz, M. A.; Garboczi, E. J.

    2014-02-18

    Systematic studies have been carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to chemistry, including X-ray diffraction and energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, were also employed. Results of these analyses will be used to shed light on the question: how does virgin powder change after being exposed to and recycled from one or more additive manufacturing build cycles? In addition, these findings can give insight into the actual additive manufacturing process.

  6. Nano powders, components and coatings by plasma technique

    DOEpatents

    McKechnie, Timothy N.; Antony, Leo V. M.; O'Dell, Scott; Power, Chris; Tabor, Terry

    2009-11-10

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  7. Nano powders, components and coatings by plasma technique

    NASA Technical Reports Server (NTRS)

    McKechnie, Timothy N. (Inventor); Antony, Leo V. M. (Inventor); O'Dell, Scott (Inventor); Power, Chris (Inventor); Tabor, Terry (Inventor)

    2009-01-01

    Ultra fine and nanometer powders and a method of producing same are provided, preferably refractory metal and ceramic nanopowders. When certain precursors are injected into the plasma flame in a reactor chamber, the materials are heated, melted and vaporized and the chemical reaction is induced in the vapor phase. The vapor phase is quenched rapidly to solid phase to yield the ultra pure, ultra fine and nano product. With this technique, powders have been made 20 nanometers in size in a system capable of a bulk production rate of more than 10 lbs/hr. The process is particularly applicable to tungsten, molybdenum, rhenium, tungsten carbide, molybdenum carbide and other related materials.

  8. A Comparison of Cocrystal Structure Solutions from Powder and Single Crystal Techniques

    SciTech Connect

    S Lapidus; P Stephens; K Arora; T Shattock; M Zaworotko

    2011-12-31

    We demonstrate the effectiveness and accuracy of high resolution powder diffraction for determination of cocrystal structures through a double-blind study. Structures of 10 cocrystals of varying complexity were determined independently using single crystal and powder techniques. The two methodologies give identical molecular packing and hydrogen bond topology, and an rms difference in covalent bond lengths of 0.035 {angstrom}. Powder techniques are clearly sufficient to establish a complete characterization of cocrystal geometry.

  9. Investigation of a novel passivation technique for gas atomized magnesium powders

    NASA Astrophysics Data System (ADS)

    Steinmetz, Andrew Douglas

    Gas atomized magnesium powders are critical for the production of a wide variety of flares, tracer projectiles, and other munitions for the United States military, along with a growing number of applications in both alloying and powder metallurgy. Gas atomization of magnesium is performed by numerous companies worldwide, but represents a single point failure within the United States as there is only one domestic producer. These powders are pyrophoric and must be handled carefully and kept dry at all times. Recent studies have explored the ability of certain fluorine containing cover gases to protect molten magnesium in casting operations from excessive vaporization and burning by modifying the native oxide (MgO) through interaction with these gas atmospheres. The present study sought to adapt this melt protection strategy for use as an in-situ passivation technique that could be employed to form a protective reaction film during gas atomization of magnesium powders. This fluorinated oxide shell was intended to provide superior coverage and adherence to the underlying metal, which may improve the ability of powders to resist ignition at elevated temperatures and during powder handling. Two candidate gases were tested in this research, SF6 and NF3, and reaction films of both were produced on miniature melt samples in a controlled environment and characterized using auger electron spectroscopy and x-ray photoelectron spectroscopy. Ultimately, SF6 was chosen to conduct a small scale magnesium atomization experiment for verification of the fluorination reaction and to experimentally test the ignition temperature of these coated particles compared to other magnesium powders available today. This novel passivation technique was found to be far superior to magnesium's native oxide at resisting ignition and, thus, to reduce the hazard associated with handling and transport of magnesium powders for defense applications. If fully commercialized, this passivation method also

  10. NIRS and MIRS technique for the determination of protein and fat content in milk powder

    NASA Astrophysics Data System (ADS)

    Wu, Di; Feng, Shuijuan; He, Chao; He, Yong

    2008-03-01

    It is very important to detect the protein and fat content in milk powder fast and non-destructively. Near-infrared (NIR) and mid-infrared(MIR) spectroscopy techniques have been compared and evaluated for the determination of the protein and fat content in milk powder with the use of Least-squares support vector machines (LS-SVM). LS-SVM models have been developed by using both NIR and MIR spectra. Both methods have shown good correlations between infrared transmission values and two nutrition contents. MIRS provided better prediction performance over NIRS. It is concluded that infrared spectroscopy technique can quantify of the protein and fat content in milk powder fast and nondestructively. The process is simple and easy to operate than chemistry methods. The results can be beneficial for designing a simple and non-destructive instrument with MIRS or NIRS spectral sensor for the determination of the protein fat content in milk powder.

  11. Unusual high Bs for Fe-based amorphous powders produced by a gas-atomization technique

    NASA Astrophysics Data System (ADS)

    Yoshida, K.; Bito, M.; Kageyama, J.; Shimizu, Y.; Abe, M.; Makino, A.

    2016-05-01

    Fe-based alloy powders with a high Fe content of about 81 at.% were produced by a gas-atomization technique. Powders of Fe81Si1.9B5.7P11.4 (at.%) alloy showed a good glass forming ability and exhibited unusual high saturation magnetic flux density of 1.57 T. The core-loss property at a frequency of 100 kHz for the compacted core made of the Fe81Si1.9B5.7P11.4 powder is evaluated to be less than 500 kW/m3 under a maximum induction of 100 mT. Moreover, good DC-superposition characteristic of the core was also confirmed. These results suggest that the present Fe-based alloy powder is promising for low-loss magnetic-core materials and expected to contribute in miniaturization of electric parts in the near future.

  12. Characterization techniques to validate models of density variations in pressed powder compacts

    SciTech Connect

    Garino, T.; Mahoney, M.; Readey, M.; Ewsuk, K.; Gieske, J.; Stoker, G.; Min, S.

    1995-07-01

    Techniques for characterizing density gradients generated during typical powder compaction processes are reviewed and several are evaluated. The techniques reviewed are ultrasonic velocity measurements, laser ultrasonic velocity measurements, x-ray radiography, autoradiography, computer tomography (CT), magnetic resonance imaging (MRI), and simple image analysis of polished cross-sections. Experimental results are reported for all of these techniques except autoradiography, CT and MRI. The test specimens examined were right circular cylinders of a high length/diameter ratio (to ensure significant density variation) pressed from commercial spray-dried alumina powders. Although the density gradients could be detected with all four techniques, ultrasonic velocity measurements gave the best contour map of gradients and is therefore most suitable for model validation. On the other hand, it was concluded that x-ray radiography is preferable in situations where cost and/or number of samples are more important that high resolution.

  13. Detection and original dose assessment of egg powders subjected to gamma irradiation by using ESR technique

    NASA Astrophysics Data System (ADS)

    Aydın, Talat

    2015-09-01

    ESR (electron spin resonance) techniques were applied for detection and original dose estimation to radiation-processed egg powders. The un-irradiated (control) egg powders showed a single resonance line centered at g=2.0086±0.0005, 2.0081±0.0005, 2.0082±0.0005 (native signal) for yolk, white and whole egg, respectively. Irradiation induced at least one additional intense singlet overlapping to the control signal and caused a significant increase in signal intensity without any changes in spectral patterns. Responses of egg powders to different gamma radiation doses in the range 0-10 kGy were examined. The stability of the radiation-induced ESR signal of irradiated egg powders were investigated over a storage period of about 5 months. Additive reirradiation of the egg powders produces a reproducible dose response function, which can be used to assess the initial dose by back-extrapolation. The additive dose method gives an estimation of the original dose within ±12% at the end of the 720 h storage period.

  14. Microstructural evolution and dielectric properties of 1D AlN powders synthesized by microwave technique

    NASA Astrophysics Data System (ADS)

    VasanthiPillay, V.; Vijayalakshmi, K.

    2012-06-01

    Low temperature synthesis of Aluminum nitride (AlN) powders through NH4Cl assisted nitridation have been studied by microwave technique. The effect of processing time on the synthesis of AlN powders has been investigated. The optimum processing time was determined to be 120 min at 630 W, 200 °C. The powders were characterized by X-ray diffraction method (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray analyzer (EDS), Fourier transform infrared spectrometer (FTIR) and Impedance analyzer. XRD results revealed that the product has wurtzite phase of AlN. SEM micrographs show a 1D nanorod of AlN with a granular morphology. FTIR spectra exhibit A1 (TO) and E1 (LO) modes of wurtzite AlN. Dielectric properties of the powders were investigated by means of C-V and C-f and ɛ'-f characteristics. The reported results indicate a reasonable quality of the obtained AlN powders with high dielectric constant, suitable for application in the fabrication of specific electronic devices.

  15. A sol-powder coating technique for fabrication of yttria stabilised zirconia

    SciTech Connect

    Wattanasiriwech, Darunee . E-mail: darunee@mfu.ac.th; Wattanasiriwech, Suthee; Stevens, Ron

    2006-08-10

    Yttria stabilised zirconia has been prepared using a simple sol-powder coating technique. The polymeric yttria sol, which was prepared using 1,3 propanediol as a network modifier, was homogeneously mixed with nanocrystalline zirconia powder and it showed a dual function: as a binder which promoted densification and a phase modifier which stabilised zirconia in the tetragonal and cubic phases. Thermal analysis and X-ray diffraction revealed that the polymeric yttria sol which decomposed at low temperature into yttrium oxide could change the m {sup {yields}} t phase transformation behaviour of the zirconia, possibly due to the small particle size and very high surface area of both yttria and zirconia particles allowing rapid alloying. The sintered samples exhibited three crystalline phases: monoclinic, tetragonal and cubic, in which cubic and tetragonal are the major phases. The weight fractions of the individual phases present in the selected specimens were determined using quantitative Rietveld analysis.

  16. Optimization of headspace solid-phase microextraction technique for extraction of volatile smokeless powder compounds in forensic applications.

    PubMed

    Chang, Kah Haw; Yew, Chong Hooi; Abdullah, Ahmad Fahmi Lim

    2014-07-01

    Smokeless powders are low explosives and are potentially found in cases involving firearms and improvised explosive devices. Apart from inorganic compound analysis, forensic determination of organic components of these materials appears as a promising alternative, especially the chromatographic techniques. This work describes the optimization of a solid-phase microextraction technique using an 85 μm polyacrylate fiber followed by gas chromatography-flame ionization detection for smokeless powder. A multivariate experimental design was performed to optimize extraction-influencing parameters. A 2(4) factorial first-order design revealed that sample temperature and extraction time were the major influencing parameters. Doehlert matrix design has subsequently selected 66°C and 21 min as the compromised conditions for the two predetermined parameters. This extraction technique has successfully detected the headspace compounds of smokeless powders from different ammunition types and allowed for their differentiation. The novel technique allows more rapid sample preparation for chromatographic detection of smokeless powders. PMID:24611488

  17. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique.

    PubMed

    Ryan, Garrett E; Pandit, Abhay S; Apatsidis, Dimitrios P

    2008-09-01

    One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications. PMID:18556060

  18. New alnico magnets fabricated from pre-alloyed gas-atomized powder through diverse consolidation techniques

    SciTech Connect

    Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.

    2015-05-25

    Fine Alnico 8 spherical powder produced by gas atomization was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and magnetic properties were analyzed and compared. The HP, HIP, and CMS magnets exhibited different features in microstructures and magnetic properties. Magnetically annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (Hcj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. As a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.

  19. New alnico magnets fabricated from pre-alloyed gas-atomized powder through diverse consolidation techniques

    DOE PAGESBeta

    Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.

    2015-05-25

    Fine Alnico 8 spherical powder produced by gas atomization was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and magnetic properties were analyzed and compared. The HP, HIP, and CMS magnets exhibited different features in microstructures and magnetic properties. Magnetically annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (Hcj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. Asmore » a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.« less

  20. Development of cobalt ferrite powder preparation employing the sol-gel technique and its structural characterisation

    NASA Astrophysics Data System (ADS)

    Sajjia, M.; Oubaha, M.; Prescott, T.; Olabi, A. G.

    2010-06-01

    This work focuses on the development of a method to make nano cobalt ferrite powder using a solgel process. A particular emphasis is devoted to the understanding of the role of the chemical parameters involved in the solgel technique, and of the heat treatment on the structures and morphologies of the materials obtained. Several samples of cobalt ferrite powder were obtained by varying the initial parameters of the process in addition to the heat treatment temperature. Xray diffraction and scanning electron microscopy were used to identify the structure and morphology of samples demonstrating the influence of the initial parameters. DTA/TGA was carried out on one sample to identify important reaction temperatures during the heat treatment. The average particle size, as estimated for one sample by the full width at half maximum (FWHM) of the strongest Xray diffraction (XRD) peak, was found to be about 45 nm. It has been found that the chelating agent and the crosslinker have a critical influence on the resultant structure, the particle size and the particle size distribution.

  1. Characterisation of titanium-titanium boride composites processed by powder metallurgy techniques

    SciTech Connect

    Selva Kumar, M.; Chandrasekar, P.; Chandramohan, P.; Mohanraj, M.

    2012-11-15

    In this work, a detailed characterisation of titanium-titanium boride composites processed by three powder metallurgy techniques, namely, hot isostatic pressing, spark plasma sintering and vacuum sintering, was conducted. Two composites with different volume percents of titanium boride reinforcement were used for the investigation. One was titanium with 20% titanium boride, and the other was titanium with 40% titanium boride (by volume). Characterisation was performed using X-ray diffraction, electron probe micro analysis - energy dispersive spectroscopy and wavelength dispersive spectroscopy, image analysis and scanning electron microscopy. The characterisation results confirm the completion of the titanium boride reaction. The results reveal the presence of titanium boride reinforcement in different morphologies such as needle-shaped whiskers, short agglomerated whiskers and fine plates. The paper also discusses how mechanical properties such as microhardness, elastic modulus and Poisson's ratio are influenced by the processing techniques as well as the volume fraction of the titanium boride reinforcement. - Highlights: Black-Right-Pointing-Pointer Ti-TiB composites were processed by HIP, SPS and vacuum sintering. Black-Right-Pointing-Pointer The completion of Ti-TiB{sub 2} reaction was confirmed by XRD, SEM and EPMA studies. Black-Right-Pointing-Pointer Hardness and elastic properties of Ti-TiB composites were discussed. Black-Right-Pointing-Pointer Processing techniques were compared with respect to their microstructure.

  2. Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines

    NASA Technical Reports Server (NTRS)

    Moracz, D. J.; Shipley, R. J.; Moxson, V. S.; Killman, R. J.; Munson, H. E.

    1992-01-01

    The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC.

  3. Single-crystal growth of 4-hydroxy-3-methoxy benzaldehyde by the Bridgman technique and its characterization

    NASA Astrophysics Data System (ADS)

    Kannan, V.; Jayaprakasan, M.; Bairava Ganesh, R.; Ramasamy, P.

    2006-08-01

    Single-crystal growth of 4-hydroxy-3-methoxy benzaldehyde (vanillin), an excellent molecular nonlinear optical (NLO) material, from the melt using the Bridgman technique is reported for the first time. Differential thermal analysis experiments indicated that the substance melts congruently at 81 °C. A precise temperature profile plot of the resistive furnace used was measured using a simple PC-based time-temperature data logging system. Powder X-ray diffraction analysis of the grown crystal revealed the crystal belongs to the monoclinic system. Fourier transform infrared spectra were used to assign various modes and identify the functional groups. The crystal exhibited a wide window of transmission unlike other organic NLO crystals. The optical second harmonic generation conversion efficiency of vanillin was determined using the Kurtz powder technique.

  4. Effects of copper content on the shell characteristics of hollow steel spheres manufactured using an advanced powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Sazegaran, Hamid; Kiani-Rashid, Ali-Reza; Khaki, Jalil Vahdati

    2016-04-01

    Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres' shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy (SEM), energy- dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.

  5. Nanospray drying as a novel technique for the manufacturing of inhalable NSAID powders.

    PubMed

    Aquino, Rita Patrizia; Stigliani, Mariateresa; Del Gaudio, Pasquale; Mencherini, Teresa; Sansone, Francesca; Russo, Paola

    2014-01-01

    The aim of this research was to evaluate the potential of the nanospray drier as a novel apparatus for the manufacturing of a dry powder for inhalation containing ketoprofen lysinate, a nonsteroidal anti-inflammatory drug able to control the inflammation in cystic fibrosis patients. We produced several ketoprofen lysinate and leucine powder batches by means of nanospray dryer, studying the influence of process parameters on yield, particle properties (size distribution and morphology), and, mainly, aerodynamic properties of powders. Micronized particles were prepared from different hydroalcoholic solutions (alcohol content from 0 to 30% v/v) using ketoprofen in its lysine salt form and leucine as dispersibility enhancer in different ratios (from 5 to 15% w/w) with a total solid concentration ranging from 1 to 7% w/v. Results indicated that the spray head equipped with a 7 µm nozzle produced powders too big to be inhaled. The reduction of nozzle size from 7 to 4 µm led to smaller particles suitable for inhalation but, at the same time, caused a dramatic increase in process time. The selection of process variables, together with the nozzle pretreatment with a surfactant solution, allowed us to obtain a free flowing powder with satisfying aerosol performance, confirming the usefulness of the nanospray drier in the production of powder for inhalation. PMID:25580462

  6. Nanospray Drying as a Novel Technique for the Manufacturing of Inhalable NSAID Powders

    PubMed Central

    Rita Patrizia, Aquino; Mariateresa, Stigliani; Pasquale, Del Gaudio; Teresa, Mencherini; Francesca, Sansone; Paola, Russo

    2014-01-01

    The aim of this research was to evaluate the potential of the nanospray drier as a novel apparatus for the manufacturing of a dry powder for inhalation containing ketoprofen lysinate, a nonsteroidal anti-inflammatory drug able to control the inflammation in cystic fibrosis patients. We produced several ketoprofen lysinate and leucine powder batches by means of nanospray dryer, studying the influence of process parameters on yield, particle properties (size distribution and morphology), and, mainly, aerodynamic properties of powders. Micronized particles were prepared from different hydroalcoholic solutions (alcohol content from 0 to 30% v/v) using ketoprofen in its lysine salt form and leucine as dispersibility enhancer in different ratios (from 5 to 15% w/w) with a total solid concentration ranging from 1 to 7% w/v. Results indicated that the spray head equipped with a 7 µm nozzle produced powders too big to be inhaled. The reduction of nozzle size from 7 to 4 µm led to smaller particles suitable for inhalation but, at the same time, caused a dramatic increase in process time. The selection of process variables, together with the nozzle pretreatment with a surfactant solution, allowed us to obtain a free flowing powder with satisfying aerosol performance, confirming the usefulness of the nanospray drier in the production of powder for inhalation. PMID:25580462

  7. Wet powder suspensions as an additional technique for the enhancement of bloodied marks.

    PubMed

    Au, Catherine; Jackson-Smith, Hayley; Quinones, Ignacio; Jones, B J; Daniel, Barbara

    2011-01-30

    The enhancement of marks in blood on dark surfaces poses significant challenges to the forensic scientist. Current methods of enhancement include the sequential use of acid dyes (acid yellow, acid violet and acid black). Acid yellow is used to greatest effect on lighter deposits of blood on a non-porous background, and is visualised using a light source which causes it to fluoresce [1]. However, further enhancement with acid violet and acid black produces a dark product which may fail to improve the contrast of the mark against a dark background. The use of wet powder suspensions (WPSs) has been proposed as a complementary procedure for use in fingermark enhancement, beyond its typical use in the enhancement of marks on adhesive surfaces. In this investigation, the use of WPS was tested in conjunction with conventional acid dye treatments on marks in blood deposited on a selection of substrates. The results demonstrated that white WPS alone or together with acid dyes results in an overall enhancement of mark quality (p<0.005) on marks deposited on smooth non-porous surfaces. The technique was shown to not interfere with subsequent presumptive tests on blood. However WPS treatments were shown to reduce the amount of DNA recoverable from the marks, resulting on an average decrease of 91% compared to untreated controls. The decline in DNA yields was shown to result in a decrease in the quality of the DNA profiles obtained. The enhancement properties of WPS were evaluated by electron microscopy. It was shown that the titanium dioxide particles in the WPS primarily interact with the non-bloodied part of the mark, thus producing a contrasting effect with the background and acid dyes. PMID:20494531

  8. Coating of pellets with micronized ethylcellulose particles by a dry powder coating technique.

    PubMed

    Pearnchob, Nantharat; Bodmeier, Roland

    2003-12-11

    Pellets were coated with ethylcellulose powder to achieve extended release. The film forming ability of ethylcellulose powder and the effect of formulation factors (plasticizer type and concentration) and curing conditions (curing temperature and time) were investigated. The coating formulation was divided into two components consisting of a powder mixture (polymer plus talc) and a mixture of liquid materials (plasticizer plus binder solution), which were sprayed separately into the coating chamber of a fluidized bed coater (Glatt GPCG-1, Wurster insert). The coated pellets were oven-cured under different conditions (60-80 degrees C, 2-24 h) without and with humidity (100% relative humidity). Propranolol hydrochloride was used as a model drug, and drug release was studied in 0.1 N HCl at 37 degrees C (USP XXV paddle method). Despite the high glass transition temperature of ethylcellulose (133.4 degrees C), micronized ethylcellulose powder can be used for dry powder coating by adjusting the coating temperature, amount and type of plasticizer applied, and curing conditions. 40% plasticizer and a curing step (80 degrees C, 24 h) were required to achieve complete coalescence of the polymer particles and extended drug release of coated pellets. Although ethylcellulose-coated pellets had an uneven surface, extended drug release could be obtained with coating level of 15%. Because of its high glass transition temperature, ethylcellulose-coated pellets showed unchanged drug release profiles upon storage at room temperature for 3 years. PMID:14643971

  9. Fabrication of dual-pore scaffolds using SLUP (salt leaching using powder) and WNM (wire-network molding) techniques.

    PubMed

    Cho, Yong Sang; Hong, Myoung Wha; Kim, So-Youn; Lee, Seung-Jae; Lee, Jun Hee; Kim, Young Yul; Cho, Young-Sam

    2014-12-01

    In this study, a novel technique was proposed to fabricate dual-pore scaffolds combining both SLUP (salt leaching using powder) and WNM (wire-network molding) techniques. This technique has several advantages: solvent-free, no limit on the use of thermoplastic polymers as a raw material, and easiness of fabricating scaffolds with dual-scale pores that are interconnected randomized small pores. To fabricate dual-pore scaffolds, PCL and NaCl powders were mixed at a certain ratio. Subsequently, needles were inserted into a designed mold, and the mixture was filled into the mold thereafter. Subsequently, after the mold was pressurized, the mold was heated to melt the PCL powders. The PCL/NaCl structure and needles were separated from the mold. The structure was sonicated to leach-out the NaCl particles and was dried. Consequently, the remaining PCL structure became the dual-pore scaffold. To compare the characteristics of dual-pore scaffolds, control scaffolds, which are 3D plotter and SLUP scaffolds were fabricated. PMID:25491863

  10. Microstructure and Mechanical Properties of Titanium Components Fabricated by a New Powder Injection Molding Technique

    SciTech Connect

    Nyberg, Eric A.; Miller, Megan R.; Simmons, Kevin L.; Weil, K. Scott

    2005-05-01

    We have developed a powder injection molding (PIM) binder system for titanium that employs naphthalene as the primary constituent to facilitate easy binder removal and mitigate problems with carbon contamination. In the study presented here, we examined densification behavior, microstructure, and mechanical properties in specimens formed by this process. In general, we found that we could achieve tensile strengths comparable to wrought titanium in the PIM-formed specimens, but that maximum elongation was less than expected. Chemical and microstructural analyses suggest that use of higher purity powder and further process optimization will lead to significant improvements in ductility.

  11. Production of ultra clean gas-atomized powder by the plasma heated tundish technique

    SciTech Connect

    Tingskog, T.A.; Andersson, V.

    1996-12-31

    The paper describes the improvements in cleanliness for different types of gas atomized powders produced by holding the melt in a Plasma Heated Tundish (PHT) before atomization. The cleanliness is measured on Hot Isostatically Pressed (HIP) or extruded samples. Significant improvements in slag levels and material properties have been achieved. On extruded powder metallurgy stainless steel and nickel alloy tubes, the rejection rate in ultra-sonic testing was reduced drastically. Tool steels and high speed steels have greatly improved ductility and bend strength.

  12. Fabrication of multi-walled carbon nanotubes-aluminum matrix composite by powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Bunakov, N. A.; Kozlov, D. V.; Golovanov, V. N.; Klimov, E. S.; Grebchuk, E. E.; Efimov, M. S.; Kostishko, B. B.

    We report on fabrication of an aluminum matrix composite containing multi-walled carbon nanotubes (MWCNTs) produced by MOCVD method and functionalized via acid treatment by a H2SO4/HNO3 mixture. Specimens were prepared by spark plasma sintering (SPS) of the aluminum powder with different amounts of functionalized MWCNTs (FMWCNTs) in the range of 0.1-1 wt.%. We studied the effect of FMWCNTs amount on microstructure and mechanical properties of composites. It is shown that functionalization allows homogeneous dispersing of the MWCNTs in Al powder. The maximal increase in micro-hardness and tensile strength is registered at 0.1 wt.%.

  13. The effect of the granulometric composition of a hydroxyapatite powder on the structure and phase composition of coatings deposited by the detonation gas spraying technique

    NASA Astrophysics Data System (ADS)

    Popova, A. A.; Yakovlev, V. I.; Legostaeva, E. V.; Sitnikov, A. A.; Sharkeev, Yu. P.

    2013-04-01

    The granulometric composition of a hydroxyapatite powder has been investigated. The initial powder has been classified into particle size ranges (0.1-10, 10-20, 20-30, and 50-300 μm). Coatings prepared from a hydroxyapatite powder of different size have been deposited by the detonation gas spraying technique. The structure and phase composition of the coatings have been studied. Changing the initial granulometric composition of the powder mixture is shown to provide control over the sprayed surface roughness.

  14. Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders

    PubMed Central

    Yun, Yifeng; Zou, Xiaodong; Hovmöller, Sven; Wan, Wei

    2015-01-01

    Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni–Se–O–Cl crystals, zeolites, germanates, metal–organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED

  15. Chemiluminescence measurements on irradiated garlic powder by the single photon counting technique

    NASA Astrophysics Data System (ADS)

    Narvaiz, P.

    1995-02-01

    The feasibility of identifying irradiated garlic powder measuring chemiluminescence by liquid scintillation spectrometry was studied. Samples packed in 100 μm thick polyethylene bags were irradiated in a 60Co semi-industrial facility, with doses of 10 and 30 kGy. Control and irradiated samples were stored at 20 ± 4°C and 70 ± 10% RH in darkness for 2 years. Assays were performed to establish the best sample concentration and pH of the buffer solution in which garlic powder was to be suspended for its measurement. The water content of garlic samples was also analyzed throughout storage time, as it related to the stability of the species causing luminescence. Chemiluminescence values diminished in every sample over storage time following an exponential pattern. Irradiated samples showed values significantly higher than those of the control samples, according to the radiation dose, throughout the storage period. This does not necessarily imply that the identification of the irradiated samples would be certain, since values of control samples coming from different origins have been found to fluctuate within a rather wide range. Nonetheless, in principle, the method looks promising for the measurement of chemiluminescence in irradiated samples

  16. Unraveling the nature of electric field- and stress- induced structural transformations in soft PZT by a new powder poling technique.

    PubMed

    Kalyani, Ajay Kumar; V, Lalitha K; James, Ajit R; Fitch, Andy; Ranjan, Rajeev

    2015-02-25

    A 'powder-poling' technique was developed to study electric field induced structural transformations in ferroelectrics exhibiting a morphotropic phase boundary (MPB). The technique was employed on soft PZT exhibiting a large longitudinal piezoelectric response (d(33) ∼ 650 pC N(-1)). It was found that electric poling brings about a considerable degree of irreversible tetragonal to monoclinic transformation. The same transformation was achieved after subjecting the specimen to mechanical stress, which suggests an equivalence of stress and electric field with regard to the structural mechanism in MPB compositions. The electric field induced structural transformation was also found to be accompanied by a decrease in the spatial coherence of polarization. PMID:25629264

  17. Precise measurement of the lattice spacing of LaB6 standard powder by the x-ray extended range technique using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Chantler, C. T.; Tran, C. Q.; Cookson, D. J.

    2004-04-01

    We used the basis of the x-ray extended range technique to measure the lattice spacing of LaB6 standard powder samples relative to silicon 640b standard powder samples with an accuracy of 5× 10-5 Å . Measurements were not constrained to one energy but were carried out over a 5 keV 20 keV energy range. These measurements used powder diffraction to determine the synchrotron beam energy, to diagnose discrepancies in the nominal calibrated beam energies, and to determine beam energy bandwidths as a function of energy. More specifically, this technique is able to yield a result independent of certain energy-dependent systematics and to yield the most accurate determination of the lattice spacing of NIST SRM 660 LaB6 standard powder so far undertaken. This has direct application to beam line energy calibration, structural evaluation, edge energy calibration, and lattice spacing determinations.

  18. Study on the optical band gap and photoluminescence of PbMoO4 nano powder synthesized by an auto igniting combustion technique

    NASA Astrophysics Data System (ADS)

    Vidya, S.; Thomas, J. K.

    2015-02-01

    Nano crystalline PbMoO4 was synthesized through an auto-ignited combustion technique. The X-ray diffraction studies of PbMoO4 nanoparticles reveals that the as-prepared powder itself is single phase and possess tetragonal structure. The average particle size of the as-prepared powder calculated using scherrer formula is 28nm. Fourier transform Infrared spectrum shows that the as prepared powder itself is phase pure with no formation of secondary phase .The optical band gap determined from UV-Visible absorption spectra is 3.20eV.Photoluminescence spectra of the samples shows blue emission.

  19. Quantification of febuxostat polymorphs using powder X-ray diffraction technique.

    PubMed

    Qiu, Jing-bo; Li, Gang; Sheng, Yue; Zhu, Mu-rong

    2015-03-25

    Febuxostat is a pharmaceutical compound with more than 20 polymorphs of which form A is most widely used and usually exists in a mixed polymorphic form with form G. In the present study, a quantification method for polymorphic form A and form G of febuxostat (FEB) has been developed using powder X-ray diffraction (PXRD). Prior to development of a quantification method, pure polymorphic form A and form G are characterized. A continuous scan with a scan rate of 3° min(-1) over an angular range of 3-40° 2θ is applied for the construction of the calibration curve using the characteristic peaks of form A at 12.78° 2θ (I/I0100%) and form G at 11.72° 2θ (I/I0100%). The linear regression analysis data for the calibration plots shows good linear relationship with R(2)=0.9985 with respect to peak area in the concentration range 10-60 wt.%. The method is validated for precision, recovery and ruggedness. The limits of detection and quantitation are 1.5% and 4.6%, respectively. The obtained results prove that the method is repeatable, sensitive and accurate. The proposed developed PXRD method can be applied for the quantitative analysis of mixtures of febuxostat polymorphs (forms A and G). PMID:25636167

  20. Application of powder metallurgy technique to produce improved bearing elements for cryogenic aerospace engine turbopumps

    NASA Technical Reports Server (NTRS)

    Moxson, V. S.; Moracz, D. J.; Bhat, B. N.; Dolan, F. J.; Thom, R.

    1987-01-01

    Traditionally, vacuum melted 440C stainless steel is used for high performance bearings for aerospace cryogenic systems where corrosion due to condensation is a major concern. For the Space Shuttle Main Engine (SSME), however, 440C performance in the high-pressure turbopumps has been marginal. A basic assumption of this study was that powder metallurgy, rather than cast/wrought, processing would provide the finest, most homogeneous bearing alloy structure. Preliminary testing of P/M alloys (hardness, corrosion resistance, wear resistance, fatigue resistance, and fracture toughness) was used to 'de-select' alloys which did perform as well as baseline 440C. Five out of eleven candidate materials (14-4/6V, X-405, MRC-2001, T-440V, and D-5) based on preliminary screening were selected for the actual rolling-sliding five-ball testing. The results of this test were compared with high-performance vacuum-melted M50 bearing steel. The results of the testing indicated outstanding performance of two P/M alloys, X-405 and MRC-2001, which eventually will be further evaluated by full-scale bearing testing.

  1. Preparation of Cu and Fly Ash Composite by Powder Metallurgy Technique

    SciTech Connect

    Chew, P. Y.; Lim, P. S.; Ng, M. C.; Zahi, S.; You, A. H.

    2011-03-30

    Cu and Fly Ash (FA) mixtures with different weight percentages were prepared. Pellets of the mixture powder were produced with the dimension of 17.7 mm in diameter and 10-15 mm in height. These different composites were compacted at a constant pressure of 280 MPa. One of the selected weight percentages was then compacted to form into pellet and sintered at different temperatures which were at 900, 950 and 1000 deg. C respectively for 2 hours. Density of green pellet was measured before sintered in furnace. After sintering, all the pellets with different temperatures were re-weighed and sintered density were calculated. The densification of the green and sintered pellets was required to be measured as one of the parameter in selection of the best material properties. Porosity of the pellet shall not be ignored in order to analyze the close-packed particles stacking in the pellet. SEM micrograph had been captured to observe the presence of pores and agglomeration of particles in the sample produced.

  2. [Application of infrared spectroscopy technique to protein content fast measurement in milk powder based on support vector machines].

    PubMed

    Wu, Di; Cao, Fang; Feng, Shui-Juan; He, Yong

    2008-05-01

    spectral analysis. Moreover, the study compared the prediction results based on near infrared spectral data and mid-infrared spectral data. The results showed that the performance of the model with mid-infrared spectral data was better than the one with near infrared spectra data. It was concluded that infrared spectroscopy technique can do the quantification of protein content in milk powder fast and non-destructively and the process was simple and easy to operate. The results of this study can be used for the design of a simple and non-destructive spectra sensor for the quantitative of protein content in milk powder. PMID:18720804

  3. Gamma scintigraphic evaluation of a novel budesonide dry powder inhaler using a validated radiolabeling technique.

    PubMed

    Warren, Simon; Taylor, Glyn; Smith, Jeffrey; Buck, Helen; Parry-Billings, Mark

    2002-01-01

    A scintigraphic study was carried out to compare the lung deposition of budesonide delivered via Clickhaler and Turbuhaler dry powder inhalers in healthy volunteers. Validation of Technetium-99m ((99m)Tc) radiolabeling of the budesonide/lactose blend used in the Clickhaler and excipient-free budesonide used in the Turbuhaler was carried out using a multistage liquid impinger, and compared with reference unlabeled devices. Budesonide was quantified using high-performance liquid chromatography and (99m)Tc by scintillation counting. The percentages (SD) of fine particles (<5.5 microm diameter) from radiolabeled and unlabeled devices were not significantly different (p > 0.05). Mean values for drug and radiolabel, respectively, were 34.6% (2.5) and 31.6% (3.8) for the Clickhaler, and 29.8% (5.5) and 31.4% (5 6) for the Turbuhaler. Fifteen healthy male volunteers received a single dose (2 x 200 microg actuations) from both devices in a double-blinded, double dummy, crossover study. During dosing, each inhalation maneuver was recorded using a computer-linked pressure transducer. To permit accurate determination of radiolabeled drug deposition, the lung margins of each volunteer were determined by Krypton-81m ((81m)Kr) gas imaging. Mean [SD] lung deposition for the Clickhaler (26.8% [6.8], RSD 25.2) was significantly greater (p < 0.001) than for the Turbuhaler (15.8% [6.6], RSD 42.2). Inspiratory flow rate parameters were similar for both devices with peak and mean values of 73 and 51 L/min for the Clickhaler, and 73 and 47 L/min for the Turbuhaler, respectively. These results indicate that, in healthy volunteers, budesonide lung deposition was higher and more consistent with the Clickhaler than with the Turbuhaler. PMID:12006142

  4. Observation of localized heating phenomena during microwave heating of mixed powders using in situ x-ray diffraction technique

    SciTech Connect

    Sabelström, N. Hayashi, M.; Watanabe, T.; Nagata, K.

    2014-10-28

    In materials processing research using microwave heating, there have been several observations of various phenomena occurring known as microwave effects. One significant example of such a phenomenon is increased reaction kinetics. It is believed that there is a possibility that this might be caused by localized heating, were some reactants would attain a higher than apparent temperature. To examine whether such thermal gradients are indeed possible, mixed powders of two microwave non-absorbers, alumina and magnesia, were mixed with graphite, a known absorber, and heated in a microwave furnace. During microwave irradiation, the local temperatures of the respective sample constituents were measured using an in situ x-ray diffraction technique. In the case of the alumina and graphite sample, a temperature difference of around 100 °C could be observed.

  5. Preparation of redispersible liposomal dry powder using an ultrasonic spray freeze-drying technique for transdermal delivery of human epithelial growth factor

    PubMed Central

    Yin, Fei; Guo, Shiyan; Gan, Yong; Zhang, Xinxin

    2014-01-01

    In this work, an ultrasonic spray freeze-drying (USFD) technique was used to prepare a stable liposomal dry powder for transdermal delivery of recombinant human epithelial growth factor (rhEGF). Morphology, particle size, entrapment efficiency, in vitro release, and skin permeability were systematically compared between rhEGF liposomal dry powder prepared using USFD and that prepared using a conventional lyophilization process. Porous and spherical particles with high specific area were produced under USFD conditions. USFD effectively avoided formation of ice crystals, disruption of the bilayer structure, and drug leakage during the liposome drying process, and maintained the stability of the rhEGF liposomal formulation during storage. The reconstituted rhEGF liposomes prepared from USFD powder did not show significant changes in morphology, particle size, entrapment efficiency, or in vitro release characteristics compared with those of rhEGF liposomes before drying. Moreover, the rhEGF liposomal powder prepared with USFD exhibited excellent enhanced penetration in ex vivo mouse skin compared with that for powder prepared via conventional lyophilization. The results suggest that ultrasonic USFD is a promising technique for the production of stable protein-loaded liposomal dry powder for application to the skin. PMID:24729702

  6. Enhancement of aged and denatured fingerprints using the cyanoacrylate fuming technique following dusting with amino acid-containing powders.

    PubMed

    Nixon, Carly; Almond, Matthew J; Baum, John V; Bond, John W

    2013-03-01

    We have carried out experiments to investigate the aging of latent fingerprints deposited on black PVC over a period of 4-15 weeks. A thumbprint was used in each case and before deposition of the print the donor rubbed their thumb around their nose to add sebaceous deposits. We have studied the effect of heat, light, and moisture and we find that moisture is the most significant factor in the degradation of the latent print. We have attempted to enhance these latent prints by dusting with valine powder or powders composed of valine mixed with gold or red fluorescent commercial fingerprint powders. To make a direct comparison between "treated" and "untreated" prints, the prints were cut in half with one-half being "treated" and one-half not. Our studies show the best results being obtained when powders of valine and red fluorescent powders are applied prior to cyanoacrylate fuming. PMID:23316682

  7. Structural, dielectric and optical characterization of BaMoO4 nano powder synthesized through an auto-igniting combustion technique

    NASA Astrophysics Data System (ADS)

    Thomas, J. K.; Vidya, S.; Solomon, Sam; Joy, K.

    2011-06-01

    Nanocrystalline BaMoO4 was synthesized through auto-ignited combustion technique. The X-ray diffraction studies of BaMoO4 nanoparticles reveals that the as-prepared powder is single phase, crystalline, and has tetragonal structure. The average particle size of the as-prepared powder from transmission electron microscopic is found to be 22nm. The thermal stability of the nano powder was examined using thermo gravimetric analysis and differential thermal analysis. The band gap determined from absorption spectra is 3.20eV.Photoluminescence spectra of the samples shows green emission peak. The dielectric constant and loss factor of the sample at 1 MHz is found to be 9.75 and 1.38×10-2 at room temperature.

  8. Improved L-C resonant decay technique for Q measurement of quasilinear power inductors: New results for MPP and ferrite powdered cores

    NASA Technical Reports Server (NTRS)

    Niedra, Janis M.; Gerber, Scott S.

    1995-01-01

    The L-C resonant decay technique for measuring circuit Q or losses is improved by eliminating the switch from the inductor-capacitor loop. A MOSFET switch is used instead to momentarily connect the resonant circuit to an existing voltage source, which itself is gated off during the decay transient. Very reproducible, low duty cycle data could be taken this way over a dynamic voltage range of at least 10:1. Circuit Q is computed from a polynomial fit to the sequence of the decaying voltage maxima. This method was applied to measure the losses at 60 kHz in inductors having loose powder cores of moly permalloy and an Mn-Zn power ferrite. After the copper and capacitor losses are separated out, the resulting specific core loss is shown to be roughly as expected for the MPP powder, but anomalously high for the ferrite powder. Possible causes are mentioned.

  9. Investigation of the Surface Stress in SiC and Diamond Nanocrystals by In-situ High Pressure Powder Diffraction Technique

    NASA Technical Reports Server (NTRS)

    Palosz, B.; Stelmakh, S.; Grzanka, E.; Gierlotka, S.; Zhao, Y.; Palosz, W.

    2003-01-01

    The real atomic structure of nanocrystals determines key properties of the materials. For such materials the serious experimental problem lies in obtaining sufficiently accurate measurements of the structural parameters of the crystals, since very small crystals constitute rather a two-phase than a uniform crystallographic phase system. As a result, elastic properties of nanograins may be expected to reflect a dual nature of their structure, with a corresponding set of different elastic property parameters. We studied those properties by in-situ high-pressure powder diffraction technique. For nanocrystalline, even one-phase materials such measurements are particularly difficult to make since determination of the lattice parameters of very small crystals presents a challenge due to inherent limitations of standard elaboration of powder diffractograms. In this investigation we used our methodology of the structural analysis, the 'apparent lattice parameter' (alp) concept. The methodology allowed us to avoid the traps (if applied to nanocrystals) of standard powder diffraction evaluation techniques. The experiments were performed for nanocrystalline Sic and GaN powders using synchrotron sources. We applied both hydrostatic and isostatic pressures in the range of up to 40 GPa. Elastic properties of the samples were examined based on the measurements of a change of the lattice parameters with pressure. The results show a dual nature of the mechanical properties (compressibilities) of the materials, indicating a complex, core-shell structure of the grains.

  10. Powders Analysis by Second Harmonic Generation Microscopy.

    PubMed

    Chowdhury, Azhad U; Zhang, Shijie; Simpson, Garth J

    2016-04-01

    A microscopy approach is developed for quantifying second harmonic generation (SHG) activity of powders that largely decouples linear and nonlinear optical interactions. Decoupling the linear and nonlinear optical effects provides a means to independently evaluate and optimize the role of each in crystal engineering efforts and facilitates direct comparisons between experimental and computational predictions of lattice hyperpolarizabilities. In this respect, the microscopy-based approach nicely complements well-established Kurtz-Perry ( J. Appl. Phys. 1968 , 39 , 3798 ) and related methods, in which collimated sources are used for powders analysis. Using a focused fundamental beam places a controllable upper bound on the interaction length, given by the depth of field. Because measurements are performed on a per-particle basis, crystal size-dependent trends can be recovered from a single powdered sample. An analytical model that includes scattering losses of a focused Gaussian beam reliably predicted several experimental observations. Specifically, the measured scattering length for SHG was in excellent agreement with the value predicted based on the particle size distribution. Additionally, histograms of the SHG intensities as functions of particle size and orientation agreed nicely with predictions from the model. PMID:26929984

  11. A combined powder melt and infiltration growth technique for fabricating nano-composited Y-Ba-Cu-O single-grain superconductor

    NASA Astrophysics Data System (ADS)

    Li, Guo-Zheng; Li, Jia-Wei; Yang, Wan-Min

    2015-10-01

    The top-seeded melt growth (MG) and infiltration growth (IG) techniques are the two most popular methods of fabricating single-grain Y-Ba-Cu-O (YBCO) bulk superconductors, which are also considered as two distinctly different processes. In this study, we report a combined powder melt and infiltration growth (PM-IG) technique for fabricating nano-composited YBCO single-grain superconductors using raw metallic oxides. In this new technique, a solid source pellet (SSP) of composition nano-Y2O3 + BaO + CuO + 1 wt.%CeO2 and a liquid source pellet (LSP) of composition nano-Y2O3 + 10BaO + 16CuO are employed, thus during heat treatment process the powder melt in SSP (corresponding to the final YBCO bulk) and liquid infiltration from LSP to SSP coexist. Because the process of precursor powder synthesis is avoided, the fabrication flow is much simplified and the experimental efficiency is increased significantly. Microstructural observation indicates that a large number of Y2BaCuO5 nano-inclusions (around 100 nm) are trapped in the YBa2Cu3O7-δ superconducting matrix. Measurements of levitation force and trapped field prove the superior performance of the nano-composited YBCO sample. The calculated zero-field J c at 77 K reaches 6.98 × 104 A cm-2, nearly 23% higher than the sample fabricated by the conventional IG technique. Thus, this study supplies a practical method for fabricating nano-composited YBCO bulk superconductors with high performance.

  12. Ultrafine BaPb/sub 1-x/Bi/sub x/O/sub 3/ powders prepared by the spray-ICP technique

    SciTech Connect

    Ono, T.; Kagawa, M.; Syono, Y.; Ikebe, M.; Muto, Y.

    1987-06-01

    Ultrafine powders of a ternary oxide system, Ba-Pb-Bi-O, were prepared by spraying aqueous mixed solutions of Ba(NO/sub 3/)/sub 2/, Pb(NO/sub 3/)/sub 2/, and Bi(NO/sub 3/)/sub 3/ into an argon inductively coupled plasma of ultrahigh temperature above 5000 K (the spray-ICP technique). Phases of the powders were largely dependent on the powder collectors enclosing the tail flame and its successive gas flow. In the water-cooled collector, mixtures of amorphous and crystalline materials were formed. In the collector where the gas flow was spontaneously maintained at about 550/sup 0/C by ICP itself, ultrafine BaPb/sub 1-x/Bi/sub x/O/sub 3/ (BPBO) 10-40 nm in particle diameter was obtained. The BPBO thus obtained had a few wt.% of water and carbonate. They were lost by heat treatment up to 550/sup 0/C, and a single-phase BPBO was formed. The as-prepared BPBO (x = 0.25) showed no superconducting transition down to 1.5 K, but the one having a particle diameter of approx. 1 ..mu..m formed by heating the as-prepared BPBO up to 1000/sup 0/C had a superconducting transition temperature at 11.3 K.

  13. Determination of tungsten in tantalum-tungsten alloy by X-ray fluorescence spectrometry using fusion, thin layer, and pressed powder pellet techniques

    NASA Astrophysics Data System (ADS)

    Tian, Lunfu; Zou, Deshuang; Dai, Yichun; Tang, Guangping

    2015-08-01

    A method is described for the X-ray fluorescence (XRF) determination of tungsten in tantalum-tungsten alloy over the range of 10.5%-13.5%. The sample was prepared by three methods, namely, borate fusion, filter paper disk, and pressed powder pellet, respectively. We compared the feature of the three methods of specimen preparation and found that filter paper disk method was the most suitable technique for specimen preparation. Furthermore, the results were compared with those given by inductively coupled plasma optical emission spectrometry (ICP-OES), and the relative standard deviation was less than 2%, which could meet the requirement of this application.

  14. The development and evaluation of an alternative powder prepregging technique for use with LaRC-TPI/graphite composites

    NASA Technical Reports Server (NTRS)

    Ogden, Andrea L.; Hyer, Michael W.; Wilkes, Garth L.; Loos, Alfred C.; St.clair, Terry L.

    1991-01-01

    An alternative powder prepregging method for use with LaRC-TPI (a thermoplastic polyimide)/graphite composites is investigated. The alternative method incorporates the idea of moistening the fiber prior to powder coating. Details of the processing parameters are given and discussed. The material was subsequently laminated into small coupons which were evaluated for processing defects using electron microscopy. After the initial evaluation of the material, no major processing defects were encountered but there appeared to be an interfacial adhesion problem. As a result, prepregging efforts were extended to include an additional fiber system, XAS, and a semicrystalline form of the matrix. The semicrystalline form of the matrix was the result of a complex heat treating cycle. Using scanning electron microscopy (SEM), the fiber/matrix adhesion was evaluated in these systems relative to the amorphous/XAS coupons. Based on these results, amorphous and semicrystalline/AS-4 and XAS materials were prepregged and laminated for transverse tensile testing. The results of these tests are presented, and in an effort to obtain more information on the effect of the matrix, remaining semicrystalline transverse tensile coupons were transformed back to the amorphous state and tested. The mechanical properties of the transformed coupons returned to the values observed for the original amorphous coupons, and the interfacial adhesion, as observed by SEM, was better than in any previous sample.

  15. Ceramic powder compaction

    SciTech Connect

    Glass, S.J.; Ewsuk, K.G.; Mahoney, F.M.

    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.

  16. Rapid synthesis of ternary carbide Ti3SiC2 through pulse-discharge sintering technique from Ti/Si/TiC powders

    NASA Astrophysics Data System (ADS)

    Zhang, Z. F.; Sun, Z. M.; Hashimoto, H.

    2002-11-01

    Ti/Si/TiC powders with molar ratios of 1:1:2 (M1) and 2:2:3 (M2) were prepared for the synthesis of a ternary carbide Ti3SiC2 by using the mixture method for 24 hours in an Ar atmosphere. The synthesis process was conducted at 1200 °C to 1400 °C under a pressure of 50 MPa, using the pulse-discharge sintering (PDS) technique. After sintering, the phase constituents and microstructures of the samples were analyzed by X-ray diffraction (XRD) technique and observed by optical microscopy and scanning electron microscopy. The results showed that the phases in all the samples consisted of Ti3SiC2 and small amounts of TiC, and the optimum sintering temperature was found to be in the relatively low range of 1250 °C to 1300 °C. By the standard additive method, the relative content of Ti3SiC2 was calculated. For the M1 samples, the lowest TiC content can be only decreased to about 3 to 4 wt pct, whereas the content of Ti3SiC2 in the M2 samples is always lower than that in the M1 samples. When the M2 powder was sintered at 1300 °C for 8 to 240 minutes, the TiC peaks were found to show a very low intensity, and the corresponding content of Ti3SiC2 was calculated to be higher than 99 wt pct. The grain size of Ti3SiC2 increased from 5 to 10 µm to 80 to 100 µm in the entire applied sintering temperature range. The relative density of the M2 samples was measured to be higher than 99 pct at sintering temperatures above 1275 °C. It indicates that the PDS technique can rapidly synthesize high-content Ti3SiC2 from the Ti/Si/TiC powders in a relatively low temperature range.

  17. Technique for determination of accurate heat capacities of volatile, powdered, or air-sensitive samples using relaxation calorimetry

    NASA Astrophysics Data System (ADS)

    Marriott, Robert A.; Stancescu, Maria; Kennedy, Catherine A.; White, Mary Anne

    2006-09-01

    We introduce a four-step technique for the accurate determination of the heat capacity of volatile or air-sensitive samples using relaxation calorimetry. The samples are encapsulated in a hermetically sealed differential scanning calorimetry pan, in which there is an internal layer of Apiezon N grease to assist thermal relaxation. Using the Quantum Design physical property measurement system to investigate benzoic acid and copper standards, we find that this method can lead to heat capacity determinations accurate to ±2% over the temperature range of 1-300K, even for very small samples (e.g., <10mg and contributing ca. 20% to the total heat capacity).

  18. Investigations of Ba{sub x}Sr{sub 1−x}TiO{sub 3} ceramics and powders prepared by direct current arc discharge technique

    SciTech Connect

    Li, Shuangbin; Wang, Xiaohan; Yao, Ying Jia, Yongzhong; Xie, Shaolei; Jing, Yan; Yuzyuk, Yu. I.

    2014-09-01

    Ba{sub x}Sr{sub 1−x}TiO{sub 3} ceramics with x ranging from 0 to 1 were prepared by direct current arc discharge technique and studied by means of x-ray diffraction (XRD) and Raman spectroscopy. The cubic-tetragonal ferroelectric phase transition in Ba{sub x}Sr{sub 1−x}TiO{sub 3} ceramics was found to occur at x ≈ 0.75. XRD investigation of as-grown BaTiO{sub 3} ceramics revealed co-existence of tetragonal and hexagonal modifications with a small amount of impurity phase BaTi{sub 4}O{sub 9}. No evidences of hexagonal phase were observed in Raman spectra of as-grown BaTiO{sub 3} ceramics, while Raman peaks related to hexagonal phase were clearly observed in the spectrum of fine-grain powders prepared from the same ceramics. A core-shell model for BaTiO{sub 3} ceramics prepared by direct current arc discharge technique is proposed. Absence of the hexagonal phase in any Ba{sub x}Sr{sub 1−x}TiO{sub 3} solid solution with x < 1 is discussed in the frame of specific atomic arrangement.

  19. Structural, Infrared and Magnetic Properties of Nanosized Ni(x)Zn1-xFe2O4 Powders Synthesized by Sol-Gel Technique.

    PubMed

    Zhu, Xiang-Rong; Zhu, Zhi-Gang; Chen, Cheng; Shen, Hong-Lie

    2015-04-01

    Ni-Zn ferrites Ni(x)Zn1-xFe2O4 (x = 0.2, 0.4, 0.5, 0.6, 0.8) powders were synthesized by sol-gel technique. Structural, infrared and magnetic properties of samples were investigated. Spinel structural characteristics are shown by XRD spectra and the morphologies observed by atomic force microscopy demonstrate the samples are in nano-range. For all the samples, FTIR spectra exhibit obvious v1 infrared absorbing bands, in the range 500-600 cm-1, corresponding to intrinsic stretching vibrations of the metal ions at the tetrahedral site (Td), Mtetra <--> O. Furthermore, the central position of v1 band is tending to shift to larger wave numbers with the increasing Ni contents in the samples. For the samples Ni(x)Zn1-xFe2O4 (x = 0.2, 0.4), the v2 infrared absorbing bands, in the range 450-385 cm(-1), corresponding to stretching vibrations of the metal ions at the octahedral-metal stretching (Oh), Mocta <--> O, were also observed. However, for samples Ni(x)Zn1-xFe2O4 with higher Ni content (x = 0.5, 0.6, 0.8), the v2 infrared absorbing bands were obscure. The magnetic hysteretic loops at room temperature obtained from vibration samples magnetometer reveal the soft magnetism of the samples. The sample with lowest Ni content, Ni0.2Zn0.8Fe2O4, presents much higher saturation field than the other samples. The coercive field rises with increased Ni content, which is ascribed to the increased magnetocrystalline anisotropy constant with Ni content. PMID:26353559

  20. 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.

  1. Improved Production Of Wrought Articles From Powders

    NASA Technical Reports Server (NTRS)

    Thomas, James R.; Singleton, Ogle R.

    1994-01-01

    Improved technique for consolidation of powders into dense articles developed. Peripheral bands used in consolidation, forging, and rolling operations. Facilitates consolidation of dispersion-hardened aluminous powders and composite mixtures for processing to such useful wrought articles as plates and sheets. Potential use in production of plates and sheets and perhaps other objects from "hard" powders, particularly from powders, objects made from which have propensity to crack when mechanically worked to other forms.

  2. Face powder poisoning

    MedlinePlus

    Face powder poisoning occurs when someone swallows or breathes in this substance. This article is for information ... The ingredients in face powder that can be harmful are: Baking soda Talcum powder Many other types of powder

  3. Microstructural changes in NiFe2O4 ceramics prepared with powders derived from different fuels in sol-gel auto-combustion technique

    NASA Astrophysics Data System (ADS)

    Chauhan, Lalita; Bokolia, Renuka; Sreenivas, K.

    2016-05-01

    Structural properties of Nickel ferrite (NiFe2O4) ceramics prepared from powders derived from sol gel auto-combustion method using different fuels (citric acid, glycine and Dl-alanine) are compared. Changes in the structural properties at different sintering temperatures are investigated. X-ray diffraction (XRD) confirms the formation of single phase material with cubic structure. Ceramics prepared using the different powders obtained from different fuels show that that there are no significant changes in lattice parameters. However increasing sintering temperatures show significant improvement in density and grain size. The DL-alanine fuel is found to be the most effective fuel for producing NIFe2O4 powders by the sol-gel auto combustion method and yields highly crystalline powders in the as-burnt stage itself at a low temperature (80 °C). Subsequent use of the powders in ceramic manufacturing produces dense NiFe2O4 ceramics with a uniform microstructure and a large grain size.

  4. Drying of sweet whey using drum dryer technique and utilization of the produced powder in French-type bread and butter cookies.

    PubMed

    Mustafa, L; Alsaed, A K; Al-Domi, H

    2014-06-01

    The objective of this study was to dry sweet liquid whey using drum dryer and to utilize the whey powder in French-type bread and cookies as a sugar substitute. The sweet whey powder was characterized chemically for ash, moisture, water activity, protein, salt, acidity and lactose contents. Optimization parameters including drying temperature, drum speed and starch addition for whey drying by drum dryer were tested to produce the best powder characteristics. The optimum temperature was 140°C at a drum speed of 20 rpm with a corn starch level of 2% (weight per weight). Sweet whey powder produced was used as a sugar replacer in French-type bread and butter cookies at substitution levels of 25, 50 and 75% of total sugars. The developed products were analyzed chemically and sensorially. The two developed products were relatively high in protein, ash, lactose and salts compared to the control samples. Regarding the sensory evaluation, the results showed that the sugar substitution of 25 and 50% in bread and cookies were significantly (p<0.05) better than the control. It can be concluded that sweet whey powder can significantly improve the quality of the studied bakery items. PMID:26035954

  5. Ceramic Powders

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In developing its product line of specialty ceramic powders and related products for government and industrial customers, including companies in the oil, automotive, electronics and nuclear industries, Advanced Refractory Technologies sought technical assistance from NERAC, Inc. in specific areas of ceramic materials and silicon technology, and for assistance in identifying possible applications of these materials in government programs and in the automotive and electronics industry. NERAC conducted a computerized search of several data bases and provided extensive information in the subject areas requested. NERAC's assistance resulted in transfer of technologies that helped ART staff develop a unique method for manufacture of ceramic materials to precise customer specifications.

  6. Energetic powder

    DOEpatents

    Jorgensen, Betty S.; Danen, Wayne C.

    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.

  7. AI-Li/SiCp composites and Ti-AI alloy powders and coatings prepared by a plasma spray atomization (PSA) technique

    NASA Astrophysics Data System (ADS)

    Khor, K. A.; Boey, F. Y. C.; Murakoshi, Y.; Sano, T.

    1994-06-01

    There has been increasing use of Al-Li alloys in the aerospace industry, due mainly to the low density and high elastic modulus of this material. However, the problem of low ductility and fracture toughness of this material has limited its present application to only weight- and stiffness-critical components. Development of Al-Li/ceramic composites is currently being investigated to enhance the service capabilities of this material. The Ti-Al alloy is also of interest to aerospace-type applications, engine components in particular, due to its attractive high-temperature properties. Preparation of fine powders by plasma melting of composite feedstock and coatings formed by plasma spraying was carried out to examine the effect of spray parameters on the microstructure and properties of these materials. Characterization of the powders and coatings was performed using the scanning electron microscope and image analyzer. Examination of the plasma-sprayed powders and coatings has shown that in the Al-Li/SiC composite there is melting of both materials to form a single composite particle. The SiC reinforcement was in the submicron range and contributed to additional strengthening of the composite body, which was formed by a cold isostatic press and consolidated by hot extrusion or hot forging processes. The plasma-sprayed Ti-Al powder showed four categories of microstructures: featureless, dendritic, cellular, and martensite-like.

  8. System Applies Polymer Powder To Filament Tow

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.; Snoha, John J.; Marchello, Joseph M.

    1993-01-01

    Polymer powder applied uniformly and in continuous manner. Powder-coating system applies dry polymer powder to continuous fiber tow. Unique filament-spreading technique, combined with precise control of tension on fibers in system, ensures uniform application of polymer powder to web of spread filaments. Fiber tows impregnated with dry polymer powders ("towpregs") produced for preform-weaving and composite-material-molding applications. System and process valuable to prepreg industry, for production of flexible filament-windable tows and high-temperature polymer prepregs.

  9. A co-precipitation technique to prepare BiNbO{sub 4}, MgTiO{sub 3} and Mg{sub 4}Ta{sub 2}O{sub 9} powders

    SciTech Connect

    Gaikwad, A.B.; Navale, S.C.; Samuel, V.; Murugan, A.V.; Ravi, V. . E-mail: ravi@ems.ncl.res.in

    2006-02-02

    A simple co-precipitation technique has been used successfully for the preparation of pure, ultrafine, single phase BiNbO{sub 4} (BN), MgTiO{sub 3} and Mg{sub 4}Ta{sub 2}O{sub 9}. An aqueous sodium hydroxide or ammonium hydroxide and ammonium carbonate solution was used to precipitate these cations as hydroxides and carbonates simultaneously under basic conditions. These precursors on heating at 750 deg. C, produce the respective powders. For comparison, these compounds were also prepared by the traditional solid state method. The phase purity and lattice parameters were studied by powder X-ray diffraction (XRD). Particle size and morphology was studied by transmission electron spectroscopy (TEM)

  10. Powder treatment process

    DOEpatents

    Weyand, J.D.

    1988-02-09

    Disclosed are: (1) a process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder. 2 figs.

  11. Powder treatment process

    DOEpatents

    Weyand, John D.

    1988-01-01

    (1) A process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder.

  12. Preparation of Orally Disintegrating Tablets Containing Powdered Tea Leaves with Enriched Levels of Bioactive Compounds by Means of Microwave Irradiation Technique.

    PubMed

    Tanaka, Hironori; Iwao, Yasunori; Izumikawa, Masahiro; Sano, Syusuke; Ishida, Hitoshi; Noguchi, Shuji; Itai, Shigeru

    2016-01-01

    In the present study, a microwave treatment process has been applied to prepare orally disintegrating tablets (ODTs) containing powdered tea leaves with enriched levels of the anti-inflammatory compounds such as chafuroside A (CFA) and chafuroside B (CFB). The use of distilled water as the adsorbed and granulation solvents in this preparation process afforded tablets with a long disintegration time (more than 120 s). The CFA and CFB contents of these tablets did not also change after 4 min of microwave irradiation due to the tablet temperature, which only increased to 100°C. In contrast, the tablet temperature increased up to 140°C after 3 min of microwave irradiation when a 1.68 M Na2HPO4 solution instead of distilled water. Notably, the disintegration time of these tablets was considerably improved (less than 20 s) compared with the microwave-untreated tablets, and there were 7- and 11-fold increases in their CFA and CFB contents. In addition, the operational conditions for the preparation of the tablets were optimized by face-centered composite design based on the following criteria: tablet hardness greater than 13 N, disintegration time less than 30 s and friability less than 0.5%. The requirements translated into X1 (the amount of granulation solvent), X2 (tableting pressure) and X3 (content of the powdered tea leaves) values of 45%, 0.43 kN and 32%, respectively, and the ODTs containing powdered tea leaves prepared under these optimized conditions were found to show excellent tablet properties and contain enriched levels of CFA and CFB. PMID:27581633

  13. Simultaneous determination of bromine and iodine in milk powder for adult and infant nutrition by plasma based techniques after digestion using microwave-induced combustion

    NASA Astrophysics Data System (ADS)

    Picoloto, Rochele S.; Doneda, Morgana; Flores, Eder L. M.; Mesko, Marcia F.; Flores, Erico M. M.; Mello, Paola A.

    2015-05-01

    In this work, bromine and iodine determination in milk powder for adult and infant nutrition was performed by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion by microwave-induced combustion (MIC). Contrarily to previous works using MIC, a higher sample mass was digested (700 mg). Water and ammonium hydroxide (10 to 100 mmol L- 1) were investigated as absorbing solutions and accurate results were achieved using a 25 mmol L- 1 NH4OH solution. Moreover, the high stability of analytes after digestion (up to 30 days) using this solution was observed. The accuracy of the proposed MIC method was evaluated using certified and reference materials of milk powder (NIST 1549 and NIST 8435). No statistical difference was observed between results obtained by MIC-ICP-MS and reference values. Results for samples were also compared with those obtained by ICP-OES and no statistical difference was observed. Microwave-assisted alkaline extraction (MW-AE) was also evaluated for milk powder using NH4OH and tetramethylammonium hydroxide solutions. Solutions obtained after digestion by MIC (whole milk powder) presented low carbon content in digests (< 25 mg L- 1) while solutions obtained after alkaline extraction presented up to 10,000 mg L- 1 of C. MIC method was preferable in view of the possibility of obtaining solutions with low carbon content even using a relatively high sample mass (up to 700 mg) avoiding additional dilution prior to ICP-MS analysis, thus allowing better detection limits. Limits of detection obtained by MIC-ICP-MS were 0.007 and 0.003 μg g- 1 for Br and I, respectively, while for MW-AE were 0.1 and 0.05 μg g- 1 respectively for Br and I. Among the main advantages of the proposed method are the use of diluted alkaline solutions that is in agreement with green analytical chemistry recommendations, the high stability of analytes in solution and the suitability of digests for

  14. Powder handling for automated fuel processing

    SciTech Connect

    Frederickson, J.R.; Eschenbaum, R.C.; Goldmann, L.H.

    1989-04-09

    Installation of the Secure Automated Fabrication (SAF) line has been completed. It is located in the Fuel Cycle Plant (FCP) at the Department of Energy's (DOE) Hanford site near Richland, Washington. The SAF line was designed to fabricate advanced reactor fuel pellets and assemble fuel pins by automated, remote operation. This paper describes powder handling equipment and techniques utilized for automated powder processing and powder conditioning systems in this line. 9 figs.

  15. Mask materials for powder blasting

    NASA Astrophysics Data System (ADS)

    Wensink, Henk; Jansen, Henri V.; Berenschot, J. W.; Elwenspoek, Miko C.

    2000-06-01

    Powder blasting, or abrasive jet machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials such as glass, silicon and ceramics. The particle jet (which expands to about 1 cm in diameter) can be optimized for etching, while the mask defines the small and complex structures. The quality of the mask influences the performance of powder blasting. In this study we tested and compared several mask types and added a new one: electroplated copper. The latter combines a highly resistant mask material for powder blasting with the high-resolution capabilities of lithography, which makes it possible to obtain an accurate pattern transfer and small feature sizes (<50 µm).

  16. Rapid breakdown anodization technique for the synthesis of high aspect ratio and high surface area anatase TiO{sub 2} nanotube powders

    SciTech Connect

    Antony, Rajini P.; Mathews, Tom; Dasgupta, Arup; Dash, S.; Tyagi, A.K.; Raj, Baldev

    2011-03-15

    Clusters of high aspect ratio, high surface area anatase-TiO{sub 2} nanotubes with a typical nanotube outer diameter of about 18 nm, wall thickness of approximately 5 nm and length of 5-10 {mu}m were synthesized, in powder form, by breakdown anodization of Ti foils in 0.1 M perchloric acid, at 10 V (299 K) and 20 V ({approx}275 and 299 K). The surface area, morphology, structure and band gap were determined from Brunauer Emmet Teller method, field emmission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, photoluminescence and diffuse reflectance spectroscopic studies. The tubular morphology and anatase phase were found to be stable up to 773 K and above 773 K anatase phase gradually transformed to rutile phase with disintegration of tubular morphology. At 973 K, complete transformation to rutile phase and disintegration of tubular morphology were observed. The band gap of the as prepared and the annealed samples varied from 3.07 to 2.95 eV with increase in annealing temperature as inferred from photoluminescence and diffuse reflectance studies. -- Graphical abstract: Display Omitted Research highlights: {yields} High aspect ratio anatase-titania nanotube powders were synthesized electrochemically. {yields} The surface area of the nanotubes were much higher than those reported. {yields} The annealing temperature limit for maintaining tubular morphology was established. {yields} The photoluminiscence spectroscopy reflected the presence of defects, annealing of defects and phase transformation. {yields} The nanotubes were of {approx}5 nm wall thickness as revealed by TEM studies.

  17. Preparation of metal diboride powders

    DOEpatents

    Brynestad, J.; Bamberger, C.E.

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

  18. Preparation of titanium diboride powder

    DOEpatents

    Brynestad, Jorulf; Bamberger, Carlos E.

    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.

  19. Autoclave heat treatment for prealloyed powder products

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Ashbrook, R. L.

    1973-01-01

    Technique could be applied directly to loose powders as part of hot pressing process of forming them to any required shapes. This would eliminate initial extrusion step commonly applied to prealloyed powders, substantially reduce cost of forming operation, and result in optimum properties.

  20. Atom probe tomography analysis of WC powder.

    PubMed

    Weidow, Jonathan

    2013-09-01

    A tantalum doped tungsten carbide powder, (W,Ta)C, was prepared with the purpose to maximise the amount of Ta in the hexagonal mixed crystal carbide. Atom probe tomography (APT) was considered to be the best technique to quantitatively measure the amount of Ta within this carbide. As the carbide powder consisted in the form of very small particles (<1 μm), a method to produce APT specimens of such a powder was developed. The powder was at first embedded in copper and a FIB-SEM workstation was used to make an in-situ lift-out from a selected powder particle. The powder particle was then deposited on a post made from a WC-Co based cemented carbide specimen. With the use of a laser assisted atom probe, it was shown that the method is working and the Ta content of the (W,Ta)C could be measured quantitatively. PMID:23507029

  1. Effect of Ca content percentage and sintering temperature on corrosion rate in Mg-Ca composite fabricated using powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Syaza Nabilla, M. S.; Zuraidawani, C. D.; Nazree, D. M.

    2016-07-01

    Magnesium (Mg) is a good element with high potential to be used in various field of work. It has the benefit of lightweight and low density its application is limited for Mg is relatively low in term of strength. Hence, calcium (Ca) is chosen to be mixed with Mg as additional element for it is lightweight and non-toxic. In this research, Mg is prepared with different weight percentage (0, 0.5, 1, 1.5 and 2 wt. %) of Cavia powder metallurgy (PM) method. The samples were sintered at 500 and 550°Cin argon atmosphere and electrochemically using SBF solution as the electrolyte medium. The effect of Ca content on corrosion rateis investigated by focusing on the microstructure and properties of sintered sample. Increase of Ca content causes reduction in grain structure due to increase Mg2Ca phase at grain boundaries. Subsequently, reduce corrosion resistance. Hence, the amount of Ca content and sintering temperature of Mg-Ca composite is controlled to acquire optimum corrosion rate.

  2. 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.

  3. Dangers of cornstarch powder on medical gloves: seeking a solution.

    PubMed

    Edlich, Richard F; Long, William B; Gubler, Dean K; Rodeheaver, George T; Thacker, John G; Borel, Lise; Chase, Margot E; Fisher, Allyson L; Mason, Shelley S; Lin, Kant Y; Cox, Mary J; Zura, Robert D

    2009-07-01

    This article reviews information on the hazards of cornstarch powder on medical gloves. Dusting powders were first applied to latex gloves to facilitate donning. After 1980, manufacturers devised innovative techniques without dusting powder. It has been well documented that these powders on gloves present a health hazard to patients and health care workers by 5 different mechanisms. First, the glove cornstarch has documented detrimental effects on wound closure techniques. Second, this powder potentiates wound infection. Third, cornstarch induces peritoneal adhesion formation and granulomatous peritonitis. Finally, these powders serve as carriers as latex allergen and they precipitate a life-threatening allergic reaction in sensitized patients. These well-documented hazards of glove powder have caused the United Kingdom and Germany to ban cornstarch powder on medical gloves over 10 years ago. PMID:19546685

  4. Face powder poisoning

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002700.htm Face powder poisoning To use the sharing features on this page, please enable JavaScript. Face powder poisoning occurs when someone swallows or breathes ...

  5. 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.

  6. Precision powder feeder

    DOEpatents

    Schlienger, M. Eric; Schmale, David T.; Oliver, Michael S.

    2001-07-10

    A new class of precision powder feeders is disclosed. These feeders provide a precision flow of a wide range of powdered materials, while remaining robust against jamming or damage. These feeders can be precisely controlled by feedback mechanisms.

  7. Aluminum powder metallurgy processing

    NASA Astrophysics Data System (ADS)

    Flumerfelt, Joel Fredrick

    In recent years, the aluminum powder industry has expanded into non-aerospace applications. However, the alumina and aluminum hydroxide in the surface oxide film on aluminum powder require high cost powder processing routes. A driving force for this research is to broaden the knowledge base about aluminum powder metallurgy to provide ideas for fabricating low cost aluminum powder components. 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). The commercial atomization methods are bench marks of current aluminum powder technology. The GARS process is a laboratory scale inert gas atomization facility. A benefit of using pure aluminum powders is an unambiguous interpretation of the results without considering the effects of alloy elements. 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 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

  8. 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.

  9. Nanoliposomal Dry Powder Formulations

    PubMed Central

    Patel, Gaurang; Chougule, Mahavir; Singh, Mandip; Misra, Ambikanandan

    2013-01-01

    Liposomal dry powder formulations (DPFs) have proven their superiority over conventional DPFs due to favorably improved pharmacokinetics and pharmacodynamics of entrapped drugs, and thus, reduced local and systemic toxicities. Nanoliposomal DPFs (NLDPFs) provide stable, high aerosolization efficiency to deep lung, prolonged drug release, slow systemic dilution, and avoid macrophage uptake of encapsulated drug by carrier-based delivery of nano-range liposomes. This chapter describes methods of preparation of nanoliposomes (NLs) and NLDPFs, using various techniques, and their characterization with respect to size distribution, flow behavior, in vitro drug release profile, lung deposition, cellular uptake and cytotoxicity, and in vivo pharmacokinetics and pharmacodynamics. Some examples have been detailed for better understanding of the methods of preparation and evaluation of NLDPFs by investigators. PMID:19903555

  10. Explosive containment with spherically tamped powders

    SciTech Connect

    Glenn, L.A.

    1986-11-15

    An effective technique for maximizing the explosive charge that a given container can safely handle is to fill the space between the charge and the container walls with a porous medium or a powder. Using the wrong powder, however, can be worse than using no powder at all. Moreover, a powder-filled container that performs very well with a small charge may also be worse than a powderless system when the charge is increased. An analysis of this problem is developed with the aim of identifying appropriate buffer material properties and the conditions under which breakdown occurs. The results are compared with various experiments performed with graphite powder, coke chunks, granular salt, snow, and vermiculite.

  11. Metallography of powder metallurgy materials

    SciTech Connect

    Lawley, Alan; Murphy, Thomas F

    2003-12-15

    The primary distinction between the microstructure of an ingot metallurgy/wrought material and one fabricated by the powder metallurgy route of pressing followed by sintering is the presence of porosity in the latter. In its various morphologies, porosity affects the mechanical, physical, chemical, electrical and thermal properties of the material. Thus, it is important to be able to characterize quantitatively the microstructure of powder metallurgy parts and components. Metallographic procedures necessary for the reliable characterization of microstructures in powder metallurgy materials are reviewed, with emphasis on the intrinsic challenges presented by the presence of porosity. To illustrate the utility of these techniques, five case studies are presented involving powder metallurgy materials. These case studies demonstrate problem solving via metallography in diverse situations: failure of a tungsten carbide-coated precipitation hardening stainless steel, failure of a steel pump gear, quantification of the degree of sinter (DOS), simulation of performance of a porous filter using automated image analysis, and analysis of failure in a sinter brazed part assembly.

  12. Multiple feed powder splitter

    DOEpatents

    Lewis, Gary K.; Less, Richard M.

    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.

  13. Granulation of fine powder

    DOEpatents

    Chen, Ching-Fong

    2016-08-09

    A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.

  14. Multiple feed powder splitter

    DOEpatents

    Lewis, Gary K.; Less, Richard M.

    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.

  15. Cow dung powder poisoning.

    PubMed

    Sherfudeen, Khaja Mohideen; Kaliannan, Senthil Kumar; Dammalapati, Pavan Kumar

    2015-11-01

    Cow dung, which has germicidal property, was used in ancient days to clean living premises in South India. Nowadays, people are using commercially available synthetic cow dung powder. It is locally known as "saani powder" in Tamil Nadu. It is freely available in homes and is sometimes accidentally consumed by children. It is available in two colors - yellow and green. Cow dung powder poisoning is common in districts of Tamil Nadu such as Coimbatore, Tirupur, and Erode. We report two cases of yellow cow dung powder poisoning from our hospital. PMID:26730123

  16. Microemulsion Synthesis of Nanoparticle PZT Powder

    NASA Astrophysics Data System (ADS)

    Amiriyan, M.; Nemati, Z. A.; Rahmanifar, M. S.; Ramesh, S.; Meenaloshini, S.; Tolouei, R.

    2011-01-01

    Nanocrystalline lead zirconate titanate (PZT) powders have been synthesized using microemulsion processing route. Microemulsion is one of the major processing techniques to synthesize a nanosize, homogenous, and almost agglomerate free ceramic powders. The ternary microemulsion system is consisted of cyclohexane as the oil phase, Triton X100 as the nonionic surfactant phase, and an aqueous phase containing 0.619 M Pb2+, 0.325 M Zr4+, and 0.3 M Ti4+, representing a Pb2+: Zr4+: Ti4+ molar ratio of 1:0.52:0.48. The ratio of these cations has been adjusted using Inductively Coupled Plasma (ICP) technique. After coprecipitation of metallic hydroxides by adding ammonia solution in microemulsion system, the PZT precursor was obtained. PZT powders have been prepared upon calcination of precursor at 800° C. Prepared powders was characterised using techniques such as X-ray diffraction, differential thermal analysis, and scanning electron microscopy. The characteristics of microemulsion processed powder is discussed, with emphasis on the presence of nano scaled PZT powder with a composition near to morphotropic phase boundary (MPB) without formation of any intermediate phases.

  17. Air permeability of powder: a potential tool for Dry Powder Inhaler formulation development.

    PubMed

    Le, V N P; Robins, E; Flament, M P

    2010-11-01

    Dry Powder Inhalers have drawn great attention from pharmaceutical scientists in recent years in particular those consisting of low-dose micronized drug particles associated with larger carrier particles and called interactive mixtures. However, there is little understanding of the relation between bulk powder properties such as powder structure and its aerodynamic dispersion performance. The aim of this work was to develop a simple method to measure the air permeability of interactive mixtures used in Dry Powder Inhalers by using Blaine's apparatus--a compendial permeameter and to relate it to the aerodynamic behaviour. The study was done with fluticasone propionate and terbutaline sulphate as drug models that were blended with several lactoses having different particle size distribution thus containing different percentages of fine particle lactose. The quality of the blends was examined by analysing the drug content uniformity. Aerodynamic evaluation of fine particle fraction was obtained using a Twin Stage Impinger. A linear correlation between a bulk property--air permeability of packed powder bed--and the fine particle fraction of drug was observed for the tested drugs. The air permeability reflects the quantity of the free particle fraction in the interparticulate spaces of powder bed that leads to fine particle fraction during fluidization in air flow. A theoretical approach was developed in order to link the air permeability of powder bed and drag force acting on powders during aerosolization process. The permeability technique developed in this study provides a potential tool for screening Dry Powder Inhaler formulations at the development stage. PMID:20854906

  18. Powder-Metallurgy Process And Product

    NASA Technical Reports Server (NTRS)

    Paris, Henry G.

    1988-01-01

    Rapid-solidification processing yields alloys with improved properties. Study undertaken to extend favorable property combinations of I/M 2XXX alloys through recently developed technique of rapid-solidification processing using powder metallurgy(P/M). Rapid-solidification processing involves impingement of molten metal stream onto rapidly-spinning chill block or through gas medium using gas atomization technique.

  19. 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.

  20. Ceramic powder synthesis in supercritical fluids

    SciTech Connect

    Adkins, C.L.J.; Russick, E.M.; Cesarano, J; Tadros, M.E.; Voigt, J.A.

    1996-04-01

    Gas-phase processing plays an important role in the commercial production of a number of ceramic powders. These include titanium dioxide, carbon black, zinc oxide, and silicon dioxide. The total annual output of these materials is on the order of 2 million tons. The physical processes involved in gas-phase synthesis are typical of those involved in solution -phase synthesis: chemical reaction kinetics, mass transfer, nucleation, coagulation, and condensation. This report focuses on the work done under a Laboratory-Directed Research and Development (LDRD) project that explored the use of various high pressure techniques for ceramic powder synthesis. Under this project, two approaches were taken. First, a continuous flow, high pressure water reactor was built and studied for powder synthesis. And second, a supercritical carbon dioxide static reactor, which was used in conjunction with surfactants, was built and used to generate oxide powders.

  1. Compaction of Titanium Powders

    SciTech Connect

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

    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 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; 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.

  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. PREPARATION OF METAL POWDER COMPACTS PRIOR TO PRESSING

    DOEpatents

    Mansfield, H.

    1958-08-26

    A method of fabricating uranium by a powder metallurgical technique is described. It consists in introducing powdered uranium hydride into a receptacle shaped to coincide with the coatour of the die cavity and heating the hydride so that it decomposes to uranium metal. The metal particles cohere in the shapw of the receptacle and thereafter the prefurmed metal powder is pressed and sintered to obtain a dense compact.

  4. Talcum powder poisoning

    MedlinePlus

    ... powder As a filler in street drugs, like heroin Other products may also contain talc. ... have developed serious lung damage and cancer. Injecting heroin that contains talc into a vein may lead ...

  5. Magnetically responsive enzyme powders

    NASA Astrophysics Data System (ADS)

    Pospiskova, Kristyna; Safarik, Ivo

    2015-04-01

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (-20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties.

  6. Gelcasting superalloy powders

    SciTech Connect

    Janney, M.A.

    1995-12-31

    Gelcasting is a process for forming inorganic powders into complex shapes. It was originally developed for ceramic powders. A slurry of powder and a monomer solution is poured in to mold and polymerized in-situ to form gelled parts. Typically, only 2-4 wt % Polymer is used. The process has both aqueous and nonaqueous versions. Gelcasting is a generic process and has been used to produce ceramic parts from over a dozen different ceramic compositions ranging from alumina-based refractories to high-performance silicon nitride. Recently, gelcasting has been applied to forming superalloy powders into complex shapes. This application has posed several challenges not previously encountered in ceramics. In particular, problems were caused by the larger particle size and the higher density of the particles. Additional problems were encountered with binder removal. How these problems were overcome will be described.

  7. 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...

  8. Pyrotechnic filled molding powder

    DOEpatents

    Hartzel, Lawrence W.; Kettling, George E.

    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.

  9. Powder Diffraction: By Decades

    NASA Astrophysics Data System (ADS)

    David, William I. F.

    This introductory chapter reviews the first 100 years of powder diffraction, decade by decade, from the earliest X-ray powder diffraction measurements of the crystal structure of graphite through to the diversity and complexity of twenty-first century powder diffraction. Carbon features as an illustrative example throughout the discussion of these ten decades from graphite and the disorder of carbon black through to lonsdaleite, the elusive hexagonal polymorph of diamond, and C60, the most symmetrical of molecules. Electronics and computing have played a leading role in the development of powder diffraction, particularly over the past 60 years, and the Moore's Law decade-by-decade rise in computing power is clear in the increasing complexity of powder diffraction experiments and material systems that can be studied. The chapter concludes with a final discussion of decades - the four decades of length-scale from the ångstrom to the micron that not only represent the domain of powder diffraction but are also the distances that will dominate twenty-first century science and technology.

  10. Recent analytical developments for powder characterization

    NASA Astrophysics Data System (ADS)

    Brackx, E.; Pages, S.; Dugne, O.; Podor, R.

    2015-07-01

    Powders and divided solid materials are widely represented as finished or intermediary products in industries as widely varied as foodstuffs, cosmetics, construction, pharmaceuticals, electronic transmission, and energy. Their optimal use requires a mastery of the transformation process based on knowledge of the different phenomena concerned (sintering, chemical reactivity, purity, etc.). Their modelling and understanding need a prior acquisition of sets of data and characteristics which are more or less challenging to obtain. The goal of this study is to present the use of different physico-chemical characterization techniques adapted to uranium-containing powders analyzed either in a raw state or after a specific preparation (ionic polishing). The new developments touched on concern dimensional characterization techniques for grains and pores by image analysis, chemical surface characterization and powder chemical reactivity characterization. The examples discussed are from fabrication process materials used in the nuclear fuel cycle.

  11. Structural characterization of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature using neutron powder diffraction and extended X-ray absorption fine structure techniques

    SciTech Connect

    Mansour, A. N.; Wong-Ng, W.; Huang, Q.; Tang, W.; Thompson, A.; Sharp, J.

    2014-08-28

    The structure of Bi{sub 2}Te{sub 3} (Seebeck coefficient Standard Reference Material (SRM™ 3451)) and the related phase Sb{sub 2}Te{sub 3} have been characterized as a function of temperature using the neutron powder diffraction (NPD) and the extended X-ray absorption fine structure (EXAFS) techniques. The neutron structural studies were carried out from 20 K to 300 K for Bi{sub 2}Te{sub 3} and from 10 K to 298 K for Sb{sub 2}Te{sub 3}. The EXAFS technique for studying the local structure of the two compounds was conducted from 19 K to 298 K. Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} are isostructural, with a space group of R3{sup ¯}m. The structure consists of repeated quintuple layers of atoms, Te2-M-Te1-M-Te2 (where M = Bi or Sb) stacking along the c-axis of the unit cell. EXAFS was used to examine the bond distances and static and thermal disorders for the first three shells of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature. The temperature dependencies of thermal disorders were analyzed using the Debye and Einstein models for lattice vibrations. The Debye and Einstein temperatures for the first two shells of Bi{sub 2}Te{sub 3} are similar to those of Sb{sub 2}Te{sub 3} within the uncertainty in the data. However, the Debye and Einstein temperatures for the third shell of Bi-Bi are significantly lower than those of the third shell of Sb-Sb. The Einstein temperature for the third shell is consistent with a soft phonon mode in both Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3}. The lower Einstein temperature of Bi-Bi relative to Sb-Sb is consistent with the lower value of thermal conductivity of Bi{sub 2}Te{sub 3} relative to Sb{sub 2}Te{sub 3}.

  12. Method for classifying ceramic powder

    NASA Technical Reports Server (NTRS)

    Takabe, K.

    1983-01-01

    Under the invented method, powder A of particles of less than 10 microns, and carrier powder B, whose average particle diameter is more than five times that of powder A, are premixed so that the powder is less than 40 wt.% of the total mixture, before classifying.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  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. 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.

  2. Ultrafine hydrogen storage powders

    DOEpatents

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    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.

  3. Enhanced centrifuge-based approach to powder characterization

    NASA Astrophysics Data System (ADS)

    Thomas, Myles Calvin

    Many types of manufacturing processes involve powders and are affected by powder behavior. It is highly desirable to implement tools that allow the behavior of bulk powder to be predicted based on the behavior of only small quantities of powder. Such descriptions can enable engineers to significantly improve the performance of powder processing and formulation steps. In this work, an enhancement of the centrifuge technique is proposed as a means of powder characterization. This enhanced method uses specially designed substrates with hemispherical indentations within the centrifuge. The method was tested using simulations of the momentum balance at the substrate surface. Initial simulations were performed with an ideal powder containing smooth, spherical particles distributed on substrates designed with indentations. The van der Waals adhesion between the powder, whose size distribution was based on an experimentally-determined distribution from a commercial silica powder, and the indentations was calculated and compared to the removal force created in the centrifuge. This provided a way to relate the powder size distribution to the rotational speed required for particle removal for various indentation sizes. Due to the distinct form of the data from these simulations, the cumulative size distribution of the powder and the Hamaker constant for the system were be extracted. After establishing adhesion force characterization for an ideal powder, the same proof-of-concept procedure was followed for a more realistic system with a simulated rough powder modeled as spheres with sinusoidal protrusions and intrusions around the surface. From these simulations, it was discovered that an equivalent powder of smooth spherical particles could be used to describe the adhesion behavior of the rough spherical powder by establishing a size-dependent 'effective' Hamaker constant distribution. This development made it possible to describe the surface roughness effects of the entire

  4. Iowa Powder Atomization Technologies

    SciTech Connect

    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.

  5. 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.

  6. Dry powder coating of pharmaceuticals: a review.

    PubMed

    Sauer, Dorothea; Cerea, Matteo; DiNunzio, James; McGinity, James

    2013-12-01

    Over the last half century, film coating technology has evolved significantly in terms of compositions and manufacturing processes, allowing for greater functionality, flexibility and efficiency. Driven by a combination of cost considerations and functionality, a range of dry powder coating technologies have been developed in both academic and industrial settings. These technologies can be generally classified into three major types based on the layer formation process: liquid assisted, thermal adhesion and electrostatic. In addition to specific manufacturing processes that must be implemented to achieve the desired product attributes, many of these techniques also require the use of novel excipients and specific formulations to provide acceptable manufacturability. This review summarizes the current dry powder coating technologies and highlights their industrial applicability with publicly disclosed case studies. Commentary on the future directions of dry powder coating is also provided. PMID:23428881

  7. 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)

  8. Novelty shop 'itching powder'.

    PubMed

    Albert, M R

    1998-08-01

    To evaluate causes of itch, commercial 'itching powders' were sought for evaluation. Only one product, produced in Germany and consisting of ground rose hips, is currently sold in novelty shops in the Boston area. These plant fibres appear to provoke itch and prickle sensations by non-allergic mechanical stimulation, similar to the action of wool fibres. PMID:9737050

  9. 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.

  10. Polymer powders for selective laser sintering (SLS)

    NASA Astrophysics Data System (ADS)

    Schmid, Manfred; Amado, Antonio; Wegener, Konrad

    2015-05-01

    Selective Laser Sintering (SLS) is close to be accepted as a production technique (Additive Manufacturing). However, one problem limiting employment of SLS for additive manufacturing in a wide-ranging industrial scope is the narrow variety of applicable polymers. The commonly applied SLS powder to date is polyamide 12 (PA 12). PA 12 or ccompounds of PA 12 (dry blends) are approximately 90 % of complete industrial consumption. The remaining small quantity is distributed on polyamide 11 (PA11) and some other `exotic' polymers (TPU, PEBA, P(E)EK). Industry is awaiting commodity polymers like polypropylene (PP) or polyethylene (PE) crucial to open new market segments. But several approaches launching those polymers failed. But what are the reasons for the difficulties in developing new SLS powders? The contribution is to answer this and highlights the combination of intrinsic and extrinsic polymer properties necessary to generate a polymer powder promising for SLS application. Particle shape, powder distribution, thermal, rheological and optical requirements must be considered and only a particularly controlled property combination leads to successful SLS implementation. Thermal behavior, particle shape and -distribution is discussed in detail, although the other properties can't be disregarded for providing new commercially successful SLS powder finally.

  11. Method to blend separator powders

    DOEpatents

    Guidotti, Ronald A.; Andazola, Arthur H.; Reinhardt, Frederick W.

    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.

  12. 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.

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

    SciTech Connect

    Jin, F.

    1995-11-01

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

  14. 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.

  15. 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 μm) 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.

  16. Reducing metal alloy powder costs for use in powder bed fusion additive manufacturing: Improving the economics for production

    NASA Astrophysics Data System (ADS)

    Medina, Fransisco

    AM. Alternative powders can be made by blending or re-spheroidizing HDH and CPTi powders. Machine modifications were performed to allow the testing and manufacturing with these low cost alternative powders. A comparison was made between alternative powders and gas atomized powders. Powders were compared in terms of morphology and at the microstructural level. Flowability of different powder blends was also measured. Finally, a comparison of parts fabricated from the multiple powder blends and gas atomized powder was made. It has been demonstrated that powder blending can produce fully dense parts in the Arcam system by utilizing the double melt technique or HIPing the built pars. The double melt technique increased the density of the sample part and modified the microstructure into finer martensitic grains. The HIP process can make a part fully dense regardless of what percentage of HDH powder blending is used. The HIP process yielded the same microstructure, regardless of the grain structure it started with. This research allows for the reduction of costs using titanium powders in the EBM system, but can also be implemented with more costly elements and alloys using other metal AM technologies. This includes niobium, tantalum, and nickel-based superalloys for use in various industries.

  17. Vacuum powder injector and method of impregnating fiber with powder

    NASA Technical Reports Server (NTRS)

    Working, Dennis C. (Inventor)

    1993-01-01

    A method and apparatus uniformly impregnate stranded material with dry powder such as low solubility, high melt flow polymer powder to produce, for example, composite prepregs. The stranded material is expanded in an impregnation chamber by an influx of air so that the powder, which may enter through the same inlet as the air, penetrates to the center of the stranded material. The stranded material then is contracted for holding the powder therein. The stranded material and powder may be pulled through the impregnation chamber in the same direction by vacuum. Larger particles of powder which do not fully penetrate the stranded material may be combed into the stranded material and powder which does not impregnate the stranded material may be collected and reused.

  18. Advanced powder processing

    SciTech Connect

    Janney, M.A.

    1997-04-01

    Gelcasting is an advanced powder forming process. It is most commonly used to form ceramic or metal powders into complex, near-net shapes. Turbine rotors, gears, nozzles, and crucibles have been successfully gelcast in silicon nitride, alumina, nickel-based superalloy, and several steels. Gelcasting can also be used to make blanks that can be green machined to near-net shape and then high fired. Green machining has been successfully applied to both ceramic and metal gelcast blanks. Recently, the authors have used gelcasting to make tooling for metal casting applications. Most of the work has centered on H13 tool steel. They have demonstrated an ability to gelcast and sinter H13 to near net shape for metal casting tooling. Also, blanks of H13 have been cast, green machined into complex shape, and fired. Issues associated with forming, binder burnout, and sintering are addressed.

  19. 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.

  20. Characterization of Metal Powders Used for Additive Manufacturing

    PubMed Central

    Slotwinski, JA; Garboczi, EJ; Stutzman, PE; Ferraris, CF; Watson, SS; Peltz, MA

    2014-01-01

    Additive manufacturing (AM) techniques1 can produce complex, high-value metal parts, with potential applications as critical parts, such as those found in aerospace components. The production of AM parts with consistent and predictable properties requires input materials (e.g., metal powders) with known and repeatable characteristics, which in turn requires standardized measurement methods for powder properties. First, based on our previous work, we assess the applicability of current standardized methods for powder characterization for metal AM powders. Then we present the results of systematic studies carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to structure and chemistry, including X-ray diffraction, energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, and X-Ray photoelectron spectroscopy were also employed. The results of these analyses show how virgin powder changes after being exposed to and recycled from one or more Direct Metal Laser Sintering (DMLS) additive manufacturing build cycles. In addition, these findings can give insight into the actual additive manufacturing process. PMID:26601040

  1. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath

    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.

  2. Powder Metallurgy Fabrication of Molybdenum Accelerator Target Disks

    SciTech Connect

    Lowden, Richard Andrew; Kiggans Jr., James O.; Nunn, Stephen D.; Parten, Randy J.

    2015-12-01

    Powder metallurgy approaches for the fabrication of accelerator target disks are being examined to support the development of Mo-99 production by NorthStar Medical Technologies, LLC. An advantage of powder metallurgy is that very little material is wasted and at present, dense, quality parts are routinely produced from molybdenum powder. The proposed targets, however, are thin wafers, 29 mm in diameter with a thickness of 0.5 mm, with very stringent dimensional tolerances. Although tooling can be machined to very high tolerance levels, the operations of powder feed, pressing and sintering involve complicated mechanisms, each of which affects green density and shrinkage, and therefore the dimensions and shape of the final product. Combinations of powder morphology, lubricants and pressing technique have been explored to produce target disks with minimal variations in thickness and little or no distortion. In addition, sintering conditions that produce densities for optimum target dissolvability are being determined.

  3. Nanocrystalline ceria powders through citrate-nitrate combustion.

    PubMed

    Purohit, R D; Saha, S; Tyagi, A K

    2006-01-01

    Nanocrystalline ceria powders have been synthesized by combustion technique using citric acid as a fuel and nitrate as an oxidizer. The auto-ignition of the gels containing cerium nitrate and citric acid resulted in ceria powders. A theory based on adiabatic flame temperature for different citric acid-to-cerium nitrate molar ratios has been proposed to explain the nature of combustion reaction and its correlation with the powder characteristics. Specific surface area and primary particle size of the ceria powder obtained through fuel-deficient precursor was found to be approximately = 127 m2/g and 2.5-10 nm, respectively. The combustion synthesized ceria powder when cold pressed and sintered in air at 1250 degrees C for 1 hour resulted in approximately = 96% of its theoretical density with sub-micron grains. PMID:16573097

  4. Advanced powder metallurgy aluminum alloys via rapid solidification technology

    NASA Technical Reports Server (NTRS)

    Ray, R.

    1984-01-01

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

  5. Silicon nitride/silicon carbide composite powders

    DOEpatents

    Dunmead, Stephen D.; Weimer, Alan W.; Carroll, Daniel F.; Eisman, Glenn A.; Cochran, Gene A.; Susnitzky, David W.; Beaman, Donald R.; Nilsen, Kevin J.

    1996-06-11

    Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

  6. Surface dose measurement using TLD powder extrapolation

    SciTech Connect

    Rapley, P. . 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.

  7. 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 (415 ksi) at 480 C (900 F) were obtained with as-superplastically deformed material. Appropriate treatments yielding materials with high-temperature tensile and stress-rupture strengths (980 C (1800 F)) were also devised.

  8. 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.

  9. LARC powder prepreg system

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.; Marchello, Joseph M.

    1990-01-01

    Thermoplastic prepregs of LARC-TPI have been produced in a fluidized bed unit on spread continuous fiber tows. The powders are melted on the fibers by radiant heating to adhere the polymer to the fiber. This process produces tow prepreg uniformly without imposing severe stress on the fibers or requiring long high temperature residence times for the polymer. Unit design theory and operating correlations have been developed to provide the basis for scale up to commercial operation. Special features of the operation are the pneumatic tow spreader, fluidized bed and resin feed systems.

  10. Heats of immersion of titania powders in primer solutions

    NASA Technical Reports Server (NTRS)

    Siriwardane, R.; Wightman, J. P.

    1983-01-01

    The oxide layer present on titanium alloys can play an important role in determining the strength and durability of adhesive bonds. Here, three titania powders in different crystalline phases, rutile-R1, anatase-A1, and anatase-A2, are characterized by several techniques. These include microelectrophoresis, X-ray diffractometry, surface area pore volume analysis, X-ray photoelectron spectroscopy, and measurements of the heats of immersion. Of the three powders, R1 has the highest heat of immersion in water, while the interaction between water and A1 powder is low. Experimental data also suggest a specific preferential interaction of polyphenylquinoxaline with anatase.

  11. Submicron silicon powder production in an aerosol reactor

    NASA Technical Reports Server (NTRS)

    Wu, J. J.; Flagan, R. C.; Gregory, O. J.

    1986-01-01

    Powder synthesis by thermally induced vapor phase reactions is described. The powder generated by this technique consists of spherical, nonagglomerated particles of high purity. The particles are uniform in size, in the 0.1-0.2-micron size range. Most of the particles are crystalline spheres. A small fraction of the spheres are amorphous. Chain agglomerates account for less than 1 percent of the spherules.

  12. Restoration of coercivity in crushed Nd Fe B magnetic powder

    NASA Astrophysics Data System (ADS)

    Kwon, H. W.; Jeong, I. C.; Kim, A. S.; Kim, D. H.; Namkung, S.; Jang, T. S.; Lee, D. H.

    2006-09-01

    An attempt has been made to prepare a high coercivity Nd-Fe-B powder from a sintered Nd 14Fe 80B 6 magnet. The combination of thermal annealing and chemical modification of particle surface using the DyF 3 salt was found to be an effective processing technique for preparing a high-coercivity powder from the crushed sintered Nd-Fe-B magnets.

  13. Plasma Influence on Tungsten Powder

    NASA Astrophysics Data System (ADS)

    Zakharov, A.; Begrambekova, S.; Grunin, A.

    Modifications of tungsten powder comprised of micro particles with dimensions: 1 ± 0.2 μm and 5 ± 1.5 μm ("small" and «large" particles) under the influence of heating, electric field and hydrogen- and argon ion irradiation are investigated in this work. The processes in irradiated powder are described and discussed. Among them there are powder outgassing, particle emission from the powder surface in the electric field, pasting of small particles all over the large ones, integration of the adhered small particles and formation of the uniform layer around the groups of large particles, cone growth on uniform layers, formation of volumetric chains of sticking together tungsten particles and their transformations. Driving forces and processes providing different types of powder modifications and the role of each of them in the specific phenomena are discussed.

  14. Effect of production conditions on the corrosion resistance of lanthanum hexaboride powders and parts made from them

    SciTech Connect

    Paderno, Y.B.; Dudnik, E.M.; Masyuk, T.V.; Tkasch, A.V.; Zaitseva, A.Z.

    1985-10-01

    The authors studied the effect of chemical and thermal treatments of an industrial LaB6 powder on the corrosion resistance of the powder itself and parts pressed hot from it. To start, two batches of an industrial lanthanum hexaboride powder were used; and any boron oxide present removed by washing the powders with warm distilled water. To free the powders of lanthanum borates and lanthanum oxide, the powders were treated with a hydrochloric acid solution. The authors determine that this hydrochloric acid cleaning method is an effective means of ridding an industrial lanthanum hexaboride powder of impurities. It is also shown that acid treatment of industrial LaB6 powders substantially improves the corrosion resistance of parts made from them by powder metallurgy techniques. Also, a mechanism of rupture of hotpressed and sintered lanthanum hexaboride parts is proposed.

  15. High Resolution Powder Diffraction and Structure Determination

    SciTech Connect

    Cox, D. E.

    1999-04-23

    It is clear that high-resolution synchrotrons X-ray powder diffraction is a very powerful and convenient tool for material characterization and structure determination. Most investigations to date have been carried out under ambient conditions and have focused on structure solution and refinement. The application of high-resolution techniques to increasingly complex structures will certainly represent an important part of future studies, and it has been seen how ab initio solution of structures with perhaps 100 atoms in the asymmetric unit is within the realms of possibility. However, the ease with which temperature-dependence measurements can be made combined with improvements in the technology of position-sensitive detectors will undoubtedly stimulate precise in situ structural studies of phase transitions and related phenomena. One challenge in this area will be to develop high-resolution techniques for ultra-high pressure investigations in diamond anvil cells. This will require highly focused beams and very precise collimation in front of the cell down to dimensions of 50 {micro}m or less. Anomalous scattering offers many interesting possibilities as well. As a means of enhancing scattering contrast it has applications not only to the determination of cation distribution in mixed systems such as the superconducting oxides discussed in Section 9.5.3, but also to the location of specific cations in partially occupied sites, such as the extra-framework positions in zeolites, for example. Another possible application is to provide phasing information for ab initio structure solution. Finally, the precise determination of f as a function of energy through an absorption edge can provide useful information about cation oxidation states, particularly in conjunction with XANES data. In contrast to many experiments at a synchrotron facility, powder diffraction is a relatively simple and user-friendly technique, and most of the procedures and software for data analysis

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

    PubMed

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

    2013-03-01

    The objective of this study was to investigate the effect of particle surface coating with magnesium stearate on the aerosolization of dry powder inhaler formulations. Micronized salbutamol sulphate as a model drug was dry coated with magnesium stearate using a mechanofusion technique. The coating quality was characterized by X-ray photoelectron spectroscopy. Powder bulk and flow properties were assessed by bulk densities and shear cell measurements. The aerosol performance was studied by laser diffraction and supported by a twin-stage impinger. High degrees of coating coverage were achieved after mechanofusion, as measured by X-ray photoelectron spectroscopy. Concomitant significant increases occurred in powder bulk densities and in aerosol performance after coating. The apparent optimum performance corresponded with using 2% w/w magnesium stearate. In contrast, traditional blending resulted in no significant changes in either bulk or aerosolization behaviour compared to the untreated sample. It is believed that conventional low-shear blending provides insufficient energy levels to expose host micronized particle surfaces from agglomerates and to distribute guest coating material effectively for coating. A simple ultra-high-shear mechanical dry powder coating step was shown as highly effective in producing ultra-thin coatings on micronized powders and to substantially improve the powder aerosolization efficiency. PMID:23196863

  17. Recovery of manganese and zinc from waste Zn-C cell powder: Mutual separation of Mn(II) and Zn(II) from leach liquor by solvent extraction technique.

    PubMed

    Biswas, Ranjit K; Habib, Mohammad A; Karmakar, Aneek K; Tanzin, Shohely

    2016-05-01

    Acidic organophosphorous extractants were screened for the mutual separation of Mn(II) and Zn(II), in a leach solution of waste Zn-C cell powder. This was done using a 2mol/L H2SO4 solution containing 2g/L glucose. Extraction characteristics of both metal ions in this mixture have been examined as functions of equilibrium pH. Although tech. and anal. grade D2EHPA are not so effective for the separation, PC88A, Cyanex 272, Cyanex 302 and Cyanex 301 are all promising for this purpose. Strippings of Mn(II) and Zn(II) from the extracted organic phases have been examined, using 0.25, 0.50 and 1mol/L H2SO4; and 1mol/L HCl, HNO3 and HClO4 at different phase ratios. H2SO4 appears to be the best stripping agent. A 1mol/L H2SO4 solution strips almost 100% of target metal ions in 10min, regardless of the extractant used. As ΔpH1/2=2.75 and as the max. separation factor (β)=1793 for Cyanex 302 at pH(eq)=4.0, a flow sheet has been developed for their mutual separations. Finally, classical precipitation methods have been adopted to obtain MnS and ZnS, which can be easily oxidized to MnO2 and ZnO, respectively. PMID:26456667

  18. Water adsorption kinetics and contact angles of pharmaceutical powders.

    PubMed

    Muster, Tim H; Prestidge, Clive A

    2005-04-01

    Water sorption kinetics and water contact angles have been characterized for a range of pharmaceutical powders: ambroxol hydrochloride, griseofulvin, N,n-octyl-D-gluconamide, paracetamol, sulfathiazole, and theophylline. The uptake of water by powder samples at saturated vapor pressure was modeled using a pseudo first-order kinetic relationship. Parameters from this model have been correlated with the concentration and reactivity of the active surface sites of the pharmaceutical powders and their contact angles. The study has shown that analysis of water adsorption kinetics can be a powerful technique for characterizing the surface chemistry and wettability of pharmaceutical powders, and is particularly sensitive to their surface modification through excipient adsorption: ethyl(hydroxyethyl)cellulose treatment of griseofulvin and butyryl chloride treatment of sulfathiazole are reported as case studies. PMID:15736196

  19. Thermal analysis of pentaerythritol tetranitrate and development of a powder aging model

    SciTech Connect

    Brown, Geoffrey W; Sandstrom, Mary M; Giambra, Anna M; Archuleta, Jose G; Monroe, Deirde C

    2009-01-01

    We have applied a range of different physical and thermal analysis techniques to characterize the thermal evolution of the specific surface area of pentaerythritol tetranitrate (PETN) powders. Using atomic force microscopy we have determined that the mass transfer mechanism leading to powder coarsening is probably sublimation and redeposition of PETN. Using thermogravimetric analysis we have measured vapor pressures of PETN powders whose aging will be simulated in future work. For one specific powder we have constructed an empirical model of the coarsening that is fit to specific surface area measurements at 60 C to 70 C to provide predictive capability of that powder's aging. Modulated differential scanning calorimetry and mass spectroscopy measurements highlight some of the thermal behavior of the powders and suggest that homologue-based eutectics and impurities are localized in the powder particles.

  20. 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.

  1. Preparation of superconductor precursor powders

    DOEpatents

    Bhattacharya, Raghunath; Blaugher, Richard D.

    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.

  2. 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 γ-Al2O3, Al-doped NiO and β-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 γ-Al2O3 spinel has paracrystalline distribution (i.e., with fair constant longitudinal spacing, but variable relative lateral translations) of defect clusters and intimate intergrowth of θ-Al2O3 and 2x(3) commensurate superstructure. The Al-doped NiO has perfect cubo-octahedron shape and as small as 5 nm in size. The β-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.

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

    DOEpatents

    Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

    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.

  4. 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.

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

    DOEpatents

    Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

    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.

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

    DOEpatents

    Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

    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.

  7. Effects of Powder Attributes and Laser Powder Bed Fusion (L-PBF) Process Conditions on the Densification and Mechanical Properties of 17-4 PH Stainless Steel

    NASA Astrophysics Data System (ADS)

    Irrinki, Harish; Dexter, Michael; Barmore, Brenton; Enneti, Ravi; Pasebani, Somayeh; Badwe, Sunil; Stitzel, Jason; Malhotra, Rajiv; Atre, Sundar V.

    2016-03-01

    The effects of powders attributes (shape and size distribution) and critical processing conditions (energy density) on the densification and mechanical properties of laser powder bed fusion (L-PBF) 17-4 PH stainless steel were studied using four types of powders. The % theoretical density, ultimate tensile strength and hardness of both water- and gas-atomized powders increased with increased energy density. Gas-atomized powders showed superior densification and mechanical properties when processed at low energy densities. However, the % theoretical density and mechanical properties of water-atomized powders were comparable to gas-atomized powders when sintered at a high energy density of 104 J/mm3. An important result of this study was that, even at high % theoretical density (97% ± 1%), the properties of as-printed parts could vary over a relatively large range (UTS: 500-1100 MPa; hardness: 25-39 HRC; elongation: 10-25%) depending on powder characteristics and process conditions. The results also demonstrate the feasibility of using relatively inexpensive water-atomized powders as starting raw material instead of the typically used gas-atomized powders to fabricate parts using L-PBF techniques by sintering at high energy densities.

  8. 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.

  9. 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.

  10. Method for molding ceramic powders

    DOEpatents

    Janney, Mark A.

    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.

  11. Laser production of articles from powders

    DOEpatents

    Lewis, Gary K.; Milewski, John O.; Cremers, David A.; Nemec, Ronald B.; Barbe, Michael R.

    1998-01-01

    Method and apparatus for forming articles from materials in particulate form in which the materials are melted by a laser beam and deposited at points along a tool path to form an article of the desired shape and dimensions. Preferably the tool path and other parameters of the deposition process are established using computer-aided design and manufacturing techniques. A controller comprised of a digital computer directs movement of a deposition zone along the tool path and provides control signals to adjust apparatus functions, such as the speed at which a deposition head which delivers the laser beam and powder to the deposition zone moves along the tool path.

  12. Laser production of articles from powders

    DOEpatents

    Lewis, G.K.; Milewski, J.O.; Cremers, D.A.; Nemec, R.B.; Barbe, M.R.

    1998-11-17

    Method and apparatus for forming articles from materials in particulate form in which the materials are melted by a laser beam and deposited at points along a tool path to form an article of the desired shape and dimensions. Preferably the tool path and other parameters of the deposition process are established using computer-aided design and manufacturing techniques. A controller comprised of a digital computer directs movement of a deposition zone along the tool path and provides control signals to adjust apparatus functions, such as the speed at which a deposition head which delivers the laser beam and powder to the deposition zone moves along the tool path. 20 figs.

  13. 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.

  14. Rotary powder feed through apparatus

    DOEpatents

    Lewis, Gary K.; Less, Richard M.

    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.

  15. 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.

  16. 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.

  17. 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.

  18. Powder collection apparatus/method

    DOEpatents

    Anderson, Iver E.; Terpstra, Robert L.; Moore, Jeffery 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.

  19. 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.

  20. Curve of the dynamic compressibility of powder media

    NASA Astrophysics Data System (ADS)

    Roman, O. V.; Shmuradko, V. T.; Tarasov, G. D.

    2006-07-01

    A technique for constructing the curves of dynamic compressibility of powder media from the results of an experiment on a plant of hydraulic explosive pressing is suggested which makes it possible to construct a certain portion of the compressibility curve with the aid of one experimental shot for any powder material in the pressure-density coordinates to the total exclusion of the apparatus that could register the dynamic parameters of the process of pressing. The technique is used for predicting the results of pressing concrete articles from powder materials, in particular, to determine the parameters of a charge and the coordinates of its disposition in a transmitting liquid medium to obtain a blank with prescribed properties.

  1. A fluidized bed process for electron sterilization of powders

    NASA Astrophysics Data System (ADS)

    Nablo, Sam V.; Wood, James C.; Desrosiers, Marc F.; Nagy, Vitaly Yu.

    1998-06-01

    A small capacity (100 g.s -1) pilot system is described for presentation of powders and fine aggregates at high velocity, to an electron beam. Electron beam dose rate is continuously monitored in real time, while the thickness of the fluidized bed used to pneumatically transport the product can be monitored and controlled using beta-gauge techniques. Using electron paramagnetic resonance (EPR) techniques, alanine power mixed with the product is used for precise determination of dose delivered to the powder stream. Thin film dosimeters transported in the bed are also used for dose determination. Results with a variety of products are presented using both dose rate and velocity as the independent variables. Lethality data for the bioburdens present in several powdered foodstuffs are discussed.

  2. Powder diffraction from a continuous microjet of submicrometer protein crystals.

    PubMed

    Shapiro, D A; Chapman, H N; Deponte, D; Doak, R B; Fromme, P; Hembree, G; Hunter, M; Marchesini, S; Schmidt, K; Spence, J; Starodub, D; Weierstall, U

    2008-11-01

    Atomic-resolution structures from small proteins have recently been determined from high-quality powder diffraction patterns using a combination of stereochemical restraints and Rietveld refinement [Von Dreele (2007), J. Appl. Cryst. 40, 133-143; Margiolaki et al. (2007), J. Am. Chem. Soc. 129, 11865-11871]. While powder diffraction data have been obtained from batch samples of small crystal-suspensions, which are exposed to X-rays for long periods of time and undergo significant radiation damage, the proof-of-concept that protein powder diffraction data from nanocrystals of a membrane protein can be obtained using a continuous microjet is shown. This flow-focusing aerojet has been developed to deliver a solution of hydrated protein nanocrystals to an X-ray beam for diffraction analysis. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryocooling. Apparatus to record protein powder diffraction in this manner has been commissioned, and in this paper the first powder diffraction patterns from a membrane protein, photosystem I, with crystallite sizes of less than 500 nm are presented. These preliminary patterns show the lowest-order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results also serve to test our aerojet injector system, with future application to femtosecond diffraction in free-electron X-ray laser schemes, and for serial crystallography using a single-file beam of aligned hydrated molecules. PMID:18955765

  3. Permanent magnet microstructures using dry-pressed magnetic powders

    NASA Astrophysics Data System (ADS)

    Oniku, Ololade D.; Bowers, Benjamin J.; Shetye, Sheetal B.; Wang, Naigang; Arnold, David P.

    2013-07-01

    This paper presents microfabrication methods and performance analysis of bonded powder permanent magnets targeting dimensions ranging from 10 µm to greater than 1 mm. For the structural definition and pattern transfer, a doctor blade technique is used to dry press magnetic powders into pre-etched cavities in a silicon substrate. The powders are secured in the cavities by one of the three methods: capping with a polyimide layer, thermal reflow of intermixed wax-binder particles, or conformal coating with a vapor-deposited parylene-C film. A systematic study of micromagnets fabricated using these methods is conducted using three different types of magnetic powders: 50 µm Nd-Fe-B, 5 µm Nd-Fe-B and 1 µm barium ferrite powder. The isotropic magnets are shown to exhibit intrinsic coercivities (Hci) as high as 720 kA m-1, remanences (Br) up to 0.5 T and maximum energy products (BHmax) up to 30 kJ m-3, depending on the magnetic powder used. Process compatibility experiments demonstrate the potential for the magnets to withstand typical microfabrication chemical exposure and thermal cycles, thereby facilitating their integration into more complex process flows. The remanences are also characterized at elevated temperatures to determine thermal sensitivities and maximum operating temperature ranges.

  4. 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.

  5. Ceramic oxide powders and the formation thereof

    DOEpatents

    Katz, Joseph L.; Hung, Cheng-Hung

    1993-01-01

    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.

  6. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Black powder. 57.6901 Section 57.6901 Mineral...-Surface and Underground § 57.6901 Black powder. (a) Black powder shall be used for blasting only when a... dimension stone. (b) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally...

  7. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Black powder. 56.6901 Section 56.6901 Mineral....6901 Black powder. (a) Black powder shall be used for blasting only when a desired result cannot be...) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally enclosed cargo space while...

  8. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  9. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  10. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Black powder. 56.6901 Section 56.6901 Mineral....6901 Black powder. (a) Black powder shall be used for blasting only when a desired result cannot be...) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally enclosed cargo space while...

  11. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Black powder. 57.6901 Section 57.6901 Mineral...-Surface and Underground § 57.6901 Black powder. (a) Black powder shall be used for blasting only when a... dimension stone. (b) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally...

  12. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Black powder. 57.6901 Section 57.6901 Mineral...-Surface and Underground § 57.6901 Black powder. (a) Black powder shall be used for blasting only when a... dimension stone. (b) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally...

  13. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Vanilla powder. 169.179 Section 169.179 Food and... § 169.179 Vanilla powder. (a) Vanilla powder is a mixture of ground vanilla beans or vanilla oleoresin...) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of...

  14. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  15. 21 CFR 169.179 - Vanilla powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Vanilla powder. 169.179 Section 169.179 Food and... § 169.179 Vanilla powder. (a) Vanilla powder is a mixture of ground vanilla beans or vanilla oleoresin...) Dried corn sirup. (6) Gum acacia. Vanilla powder may contain one or any mixture of two or more of...

  16. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Black powder. 56.6901 Section 56.6901 Mineral....6901 Black powder. (a) Black powder shall be used for blasting only when a desired result cannot be...) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally enclosed cargo space while...

  17. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Copper powder. 73.1647 Section 73.1647 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing metallic powder prepared from virgin electrolytic copper....

  18. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Copper powder. 73.1647 Section 73.1647 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing metallic powder prepared from virgin electrolytic copper....

  19. On the Methods to Measure Powder Flow.

    PubMed

    Tan, Geoffrey; Morton, David A V; Larson, Ian

    2015-01-01

    The flow of powders can often play a critical role in the manufacturing of pharmaceutical products. Many of these processes require good, consistent and predictable flow of powders to ensure continuous production of pharmaceutical dosages and to ensure their quality. Therefore, the flow of powders is of paramount importance to the pharmaceutical industry and thus the measuring and evaluating of powder flow is of utmost importance. At present, there are numerous methods in which the flow of powders can be measured. However, due to the complex and environment-dependent nature of powders, no one method exists that is capable of providing a complete picture of the behaviour of powders under dynamic conditions. Some of the most commonly applied methods to measure the flow of powders include: density indices, such as the Carr index and Hausner ratio, powder avalanching, the angle of repose (AOR), flow through an orifice, powder rheometry and shear cell testing. PMID:26446467

  20. Amorphous Fe72Cr8P13C7 Powder with High Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Cho, Kangjo; Hwang, Choll-Hong; Pak, Chang-Su; Ryeom, Yeong-Jo

    1982-07-01

    Amorphous Fe72Cr8P13C7 powder has been prepared by the spark erosion technique and its corrosion behavior investigated potentiodynamically. It is concluded that the powder prepared this way possesses a relatively high corrosion resistance, as does amorphous Fe72Cr8P13C7 ribbon prepared by rapid quenching.

  1. NanoComposite Stainless Steel Powder Technologies

    SciTech Connect

    DeHoff, R.; Glasgow, C.

    2012-07-25

    Oak Ridge National Laboratory has been investigating a new class of Fe-based amorphous material stemming from a DARPA, Defense Advanced Research Projects Agency initiative in structural amorphous metals. Further engineering of the original SAM materials such as chemistry modifications and manufacturing processes, has led to the development of a class of Fe based amorphous materials that upon processing, devitrify into a nearly homogeneous distribution of nano sized complex metal carbides and borides. The powder material is produced through the gas atomization process and subsequently utilized by several methods; laser fusing as a coating to existing components or bulk consolidated into new components through various powder metallurgy techniques (vacuum hot pressing, Dynaforge, and hot isostatic pressing). The unique fine scale distribution of microstructural features yields a material with high hardness and wear resistance compared to material produced through conventional processing techniques such as casting while maintaining adequate fracture toughness. Several compositions have been examined including those specifically designed for high hardness and wear resistance and a composition specifically tailored to devitrify into an austenitic matrix (similar to a stainless steel) which poses improved corrosion behavior.

  2. Advancements in application of thermoplastic powder coatings for railcar linings

    SciTech Connect

    Horton, D.; Loustaunau, P.J.

    1996-10-01

    Powder coatings offer many benefits for coating applications. These products offer zero VOC emissions and improved performance. Railcars have been largely excluded from these applications due to their physical size. With innovative coating materials and coating techniques, these parts may be economically lined with high performance polymer coatings.

  3. Powder metallurgy of vanadium and its alloys (review)

    SciTech Connect

    Radomysel'skii, I.D.; Solntsev, V.P.; Evtushenko, O.V.

    1987-10-01

    This article reviews the current powder metallurgy technology of vanadium and its alloys. Data are given on sintering, compacting, electrowinning and other current production techniques, as well as on the corrosion behavior and mechanical and physical properties of alloys produced by these different methods. The use of vanadium alloys as reactor and jet engine materials is also briefly discussed.

  4. Glove powder: implications for infection control.

    PubMed

    Dave, J; Wilcox, M H; Kellett, M

    1999-08-01

    Gloves are increasingly promoted for use by healthcare workers, but this use is not without risk. Data associating powdered gloves with an increased risk of latex allergy is available and there is circumstantial evidence that the powder used may increase bacterial environmental contamination. In animal models, corn starch, the material used as glove powder, promotes wound infection. Infection control teams need to be aware of this evidence and should support switching from use of powdered to powder free gloves. PMID:10467541

  5. Developments in Die Pressing Strategies for Low-Cost Titanium Powders

    SciTech Connect

    Hovanski, Yuri; Weil, K. Scott; Lavender, Curt A.

    2009-05-01

    Recent developments in the production of low-cost titanium powders have rejuvenated interest in manufacturing titanium powder metallurgy components by direct press and sinter techniques. However excessive friction typically observed during titanium powder pressing operations leads to numerous problems ranging from non-homogeneous green densities of the compacted powder to excessive part ejection forces and reduced die life due to wear and galling. An instrumented double-acting die press was developed to both investigate the mechanics of titanium powder pressing (particularly for the new low-cost powder morphologies) and to screen potential lubricants that could reduce frictional effects. As will be discussed, the instrument was used to determine friction coefficients and to evaluate a number of candidate lubricants. These results were then used to optimize the lubricant system to reduce die-wall stresses and improve part density uniformity.

  6. NON-MELT PROCESSING OF "LOW-COST", ARMSTRONG TITANIUM AND TITANIUM ALLOY POWDERS

    SciTech Connect

    Peter, William H; Blue, Craig A; Clive, Scorey; Ernst, Bill; McKernan, John; Kiggans, Jim; Rivard, John D; Yu, Dr. Charlie

    2007-01-01

    In the last decade, a considerable effort has been made to develop new methods for producing low cost titanium and titanium powders. The Armstrong process is a new method of producing titanium powder via reducing TiCl4 vapor in molten sodium. The process is scalable, and can be used to produce pre-alloyed powders. Non-melt processing and powder metallurgy approaches are economically viable with the commercially pure powders. In this investigation, several non-melt processing technologies, including vacuum hot pressing, extrusion, roll compaction, and forging techniques, will be evaluated using the Armstrong titanium powders. The metallurgical, chemical, and mechanical properties of the processed titanium samples will be discussed.

  7. Novel hollow powder porous structures

    SciTech Connect

    Sypeck, D.J.; Parrish, P.A.; Wadley, H.N.G.

    1998-12-31

    Recent finite element calculations indicate that structures constructed from partially compacted hollow spheres exhibit a greater stiffness and strength than many other cellular structures at comparable density. It has been observed that gas atomization of metallic powders often leads to entrapment of the flow field gas. The resulting hollow powders are an unwanted by-product in the sense that they lead to porosity and future sites of defect in solid parts. Here a method is developed to separate the hollow powders according to their size, shape and density. They are then consolidated to a porous structure. Examples of this are given for both a titanium alloy and a nickel-base superalloy. The compressive mechanical properties are measured and compared to those of other porous structures.

  8. Powder metal technologies and applications

    SciTech Connect

    Eisen, W.B.; Ferguson, B.L.; German, R.M.; Iacocca, R.; Lee, P.W.; Madan, D.; Moyer, K.; Sanderow, H.; Trudel, Y.

    1998-12-31

    This volume is: (1) a completely updated and expanded edition in all areas of powder production, sampling, characterization, shaping, consolidation, sintering, quality control, machining, heat treating, and P/M applications; (2) single source for practical engineering information on sintering practices, tool design, P/M metallography, dimensional control, part design, powders, binders, lubricants, and the processing, properties, and performance of P/M materials in different production technologies and applications; (3) comprehensive coverage of P/M technologies and applications including warm compaction, injection molding, rapid prototyping, thermal spray forming, reactive sintering, and P/M gears, bearings, high-performance parts, composites, machine parts, electric contacts, magnetic materials, metallic foams, hardfacing powders, automotive parts, and more.

  9. PROCESS OF FORMING POWDERED MATERIAL

    DOEpatents

    Glatter, J.; Schaner, B.E.

    1961-07-14

    A process of forming high-density compacts of a powdered ceramic material is described by agglomerating the powdered ceramic material with a heat- decompossble binder, adding a heat-decompossble lubricant to the agglomerated material, placing a quantity of the material into a die cavity, pressing the material to form a compact, pretreating the compacts in a nonoxidizing atmosphere to remove the binder and lubricant, and sintering the compacts. When this process is used for making nuclear reactor fuel elements, the ceramic material is an oxide powder of a fissionsble material and after forming, the compacts are placed in a cladding tube which is closed at its ends by vapor tight end caps, so that the sintered compacts are held in close contact with each other and with the interior wall of the cladding tube.

  10. Ceramic Tool For Preconsolidation Of Powder-Coated Towpreg

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.; Sandusky, Donald A.; Marchello, Joseph M.

    1994-01-01

    Tool converts partly formed towpreg into preconsolidated towpreg ribbon. In technique, towpreg coated with thermoplastic powder converted into preconsolidated ribbon without use of plasticizers or solvents. Relying on melt flow and proper application of tension, friction, and cooling, technique ensures both consistent distribution of polymer within, and consistent cross section of ribbon. Ceramic preconsolidation tool includes heated and cooled halves thermally insulated from each other.

  11. Flexible thermoset towpregs by electrostatic powder fusion coating

    NASA Technical Reports Server (NTRS)

    Yang, Pei-Hua; Varughese, Babu; Muzzy, John D.

    1991-01-01

    Thermoset prepregs of expoxy and polyimide have been produced by electrostatic deposition of charged fluidized polymer powders on spread continuous fiber tows. The powders are melted onto the fibers by radiant heating to adhere the polymer to the fiber. This process produces towpreg uniformly and rapidly without imposing severe stresses on the fibers. The towpregs produced by this novel process were consolidated to make unidirectional laminates for mechanical testing. Low void content samples have been made and demonstrated by C-scan and scanning electron microscopy. The mechanical properties of unidirectional laminates are equivalent to composites fabricated by conventional techniques.

  12. Ceramics in gas turbine: Powder and process characterization

    NASA Technical Reports Server (NTRS)

    Dutta, S.

    1977-01-01

    Some of the intrinsic properties of various forms of Si3N4 and SiC are listed and limitations of such materials' availability are pointed out. The essential features/parameters to characterize a batch of powder are discussed including the standard techniques for such characterization. In process characterization, parameters in sintering, reaction sintering, and hot pressing processes are discussed including the factors responsible for strength limitations in ceramic bodies. Significant improvements in material properties can be achieved by reducing or eliminating the strength limiting factors with consistent powder and process characterization along with process control.

  13. Oxide-dispersion strengthening of porous powder metalurgy parts

    DOEpatents

    Judkins, Roddie R.

    2002-01-01

    Oxide dispersion strengthening of porous metal articles includes the incorporation of dispersoids of metallic oxides in elemental metal powder particles. Porous metal articles, such as filters, are fabricated using conventional techniques (extrusion, casting, isostatic pressing, etc.) of forming followed by sintering and heat treatments that induce recrystallization and grain growth within powder grains and across the sintered grain contact points. The result is so-called "oxide dispersion strengthening" which imparts, especially, large increases in creep (deformation under constant load) strength to the metal articles.

  14. Compact, Non-Pneumatic Rock-Powder Samplers

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Bar-Cohen, Yoseph; Badescu, Mircea; Bao, Xiaoqi; Chang, Zensheu; Jones, Christopher; Aldrich, Jack

    2008-01-01

    Tool bits that automatically collect powdered rock, permafrost, or other hard material generated in repeated hammering action have been invented. The present invention pertains to the special case in which it is desired to collect samples in powder form for analysis by x-ray diffraction and possibly other techniques. The present invention eliminates the need for both the mechanical collection equipment and the crushing chamber and the pneumatic collection equipment of prior approaches, so that it becomes possible to make the overall sample-acquisition apparatus more compact.

  15. Effects of red pepper powder on microbial communities and metabolites during kimchi fermentation.

    PubMed

    Jeong, Sang Hyeon; Lee, Hyo Jung; Jung, Ji Young; Lee, Se Hee; Seo, Hye-Young; Park, Wan-Soo; Jeon, Che Ok

    2013-01-01

    To investigate the effects of red pepper powder on kimchi fermentation, Baechu (Chinese cabbage) and Mu (radish) kimchi, with and without red pepper powder, were prepared and their characteristics, including pH, colony-forming units (CFU), microbial communities, and metabolites, were periodically monitored for 40days. Measurements of pH and CFU showed that the lag phases of kimchi fermentation were clearly extended by the addition of red pepper powder. Microbial community analysis using a barcoded pyrosequencing analysis showed that the bacterial diversities in kimchi with red pepper powder decreased more slowly than kimchi without red pepper powder as kimchi fermentation progressed. The kimchi microbial communities were represented mainly by the genera Leuconostoc and Lactobacillus in all kimchi, and the abundance of Weissella was negligible in kimchi without red pepper powder. However, interestingly, kimchi with red pepper powder contained much higher proportions of Weissella than kimchi without red pepper powder, while the proportions of Leuconostoc and Lactobacillus were evidently lower in kimchi with red pepper powder compared to kimchi without red pepper powder. Metabolite analysis using a (1)H NMR technique also showed that the fermentation of kimchi with red pepper powder progressed a little more slowly than that of kimchi without red pepper powder. Principle component analysis using microbial communities and metabolites supported the finding that the addition of red pepper powder into kimchi resulted in the slowing of the kimchi fermentation process, especially during the early fermentation period and influenced the microbial succession and metabolite production during the kimchi fermentation processes. PMID:23290232

  16. The use of elemental powder mixes in laser-based additive manufacturing

    NASA Astrophysics Data System (ADS)

    Clayton, Rodney Michael

    This study examines the use and functionality of laser depositing alloys from mixes of elemental metallic powders. Through the use of laser-based additive manufacturing (LAM), near net-shaped 3-Dimensional metallic parts can be produced in a layer-by-layer fashion. It is customary for pre-alloyed powders to be used in this process. However, mixes of elemental powders can be used to produce alloys that are formed during the deposition process. This alternative technique requires that the elemental powders adequately mix during deposition for a homogeneous deposit to be produced. Cost savings and versatility are among several of the advantages to using elemental powder mixes in LAM. Representative alloys of 316 and 430 Stainless Steel (SS) and Ti-6Al-4V were produced with elemental powder mixes during this research. These deposits were then compared to deposits of the same material manufactured with pre-alloyed powder. Comparison between the two types of samples included; EDS analysis to examine chemical homogeneity, metallography techniques to compare microstructures, and finally hardness testing to observe mechanical properties. The enthalpy of mixing is also discussed as this can impact the resulting homogeneity of deposits produced with mixes of elemental powders. Some differences were observed between the two types of deposits for 430 SS and Ti-6Al-4V. Results indicate that deposits fabricated with mixes of elemental powders can be produced to an equivalent quality of pre-alloyed powder deposits for 316 SS. This research also proposes potential alloys that could be considered for use in an elemental powder mixing technique.

  17. Characterisation of Aronia powders obtained by different drying processes.

    PubMed

    Horszwald, Anna; Julien, Heritier; Andlauer, Wilfried

    2013-12-01

    Nowadays, food industry is facing challenges connected with the preservation of the highest possible quality of fruit products obtained after processing. Attention has been drawn to Aronia fruits due to numerous health promoting properties of their products. However, processing of Aronia, like other berries, leads to difficulties that stem from the preparation process, as well as changes in the composition of bioactive compounds. Consequently, in this study, Aronia commercial juice was subjected to different drying techniques: spray drying, freeze drying and vacuum drying with the temperature range of 40-80 °C. All powders obtained had a high content of total polyphenols. Powders gained by spray drying had the highest values which corresponded to a high content of total flavonoids, total monomeric anthocyanins, cyaniding-3-glucoside and total proanthocyanidins. Analysis of the results exhibited a correlation between selected bioactive compounds and their antioxidant capacity. In conclusion, drying techniques have an impact on selected quality parameters, and different drying techniques cause changes in the content of bioactives analysed. Spray drying can be recommended for preservation of bioactives in Aronia products. Powder quality depends mainly on the process applied and parameters chosen. Therefore, Aronia powders production should be adapted to the requirements and design of the final product. PMID:23871034

  18. Powder processing of hybrid titanium neural electrodes

    NASA Astrophysics Data System (ADS)

    Lopez, Jose Luis, Jr.

    A preliminary investigation into the powder production of a novel hybrid titanium neural electrode for EEG is presented. The rheological behavior of titanium powder suspensions using sodium alginate as a dispersant are examined for optimal slip casting conditions. Electrodes were slip cast and sintered at 950°C for 1 hr, 1000°C for 1, 3, and 6 hrs, and 1050°C for 1 hr. Residual porosities from sintering are characterized using Archimedes' technique and image analysis. The pore network is gel impregnated by submerging the electrodes in electrically conductive gel and placing them in a chamber under vacuum. Gel evaporation of the impregnated electrodes is examined. Electrodes are characterized in the dry and gelled states using impedance spectrometry and compared to a standard silver- silver chloride electrode. Power spectral densities for the sensors in the dry and gelled state are also compared. Residual porosities for the sintered specimens were between 50.59% and 44.81%. Gel evaporation tests show most of the impregnated gel evaporating within 20 min of exposure to atmospheric conditions with prolonged evaporation times for electrodes with higher impregnated gel mass. Impedance measurements of the produced electrodes indicate the low impedance of the hybrid electrodes are due to the increased contact area of the porous electrode. Power spectral densities of the titanium electrode behave similar to a standard silver-silver chloride electrode. Tests suggest the powder processed hybrid titanium electrode's performance is better than current dry contact electrodes and comparable to standard gelled silver-silver chloride electrodes.

  19. Direct laser powder deposition - 'State of the Art'

    SciTech Connect

    Sears, J.W.

    1999-11-01

    Recent developments on Laser Cladding and Rapid Prototyping have led to Solid Freeform Fabrication (SFF) technologies that produce net shape metal components by laser fusion of metal powder alloys. These processes are known by various names such as Directed Light Fabrication (DLF{trademark}), Laser Engineered Net Shaping (LENS{trademark}), and Direct Metal Deposition (DMD{trademark}) to name a few. These types of processes can be referred to as direct laser powder deposition (DLPD). DLPD involves fusing metal alloy powders in the focal point of a laser (or lasers) that is (are) being controlled by Computer Aided Design-Computer Aided Manufacturing (CAD-CAM) technology. DLPD technology has the capability to produce fully dense components with little need for subsequent processing. Research and development of DLPD is being conducted throughout the world. The list of facilities conducting work in this area continues to grow (over 25 identified in North America alone). Selective Laser Sintering (SLS{trademark}) is another type of SFF technology based on laser fusion of powder. The SLS technology was developed as a rapid prototyping technique, whereas DLPD is an extension of the laser cladding technology. Most of the effort in SLS has been directed towards plastics and ceramics. In SLS, the powder is pre-placed by rolling out a layer for each laser pass. The computer control selects where in the layer the powder will be sintered by the laser. Sequential layers are sintered similarly forming a shape. In DLPD, powder is fed directly into a molten metal pool formed at the focal point of the laser where it is melted. As the laser moves on the material it rapidly resolidifies to form a shape. This talk elaborates on the state of these developments.

  20. Multiscale Modeling of Powder Bed–Based Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Markl, Matthias; Körner, Carolin

    2016-07-01

    Powder bed fusion processes are additive manufacturing technologies that are expected to induce the third industrial revolution. Components are built up layer by layer in a powder bed by selectively melting confined areas, according to sliced 3D model data. This technique allows for manufacturing of highly complex geometries hardly machinable with conventional technologies. However, the underlying physical phenomena are sparsely understood and difficult to observe during processing. Therefore, an intensive and expensive trial-and-error principle is applied to produce components with the desired dimensional accuracy, material characteristics, and mechanical properties. This review presents numerical modeling approaches on multiple length scales and timescales to describe different aspects of powder bed fusion processes. In combination with tailored experiments, the numerical results enlarge the process understanding of the underlying physical mechanisms and support the development of suitable process strategies and component topologies.

  1. Ceramics in gas turbines - Powder and process characterization

    NASA Technical Reports Server (NTRS)

    Dutta, S.

    1977-01-01

    The role of powder and process characterization in producing high quality silicon nitride and silicon carbide components, for gas turbine applications, is described. Some of the intrinsic properties of various forms of Si3N4 and SiC are listed and limitations of such materials' availability have been pointed out. The essential features/parameters to characterize a batch of powder have been discussed including the standard techniques for such characterization. In process characterization, parameters in sintering, reaction sintering, and hot pressing processes are discussed including the factors responsible for strength limitations in ceramic bodies. It is inevitable that significant improvements in material properties can be achieved by reducing or eliminating the strength limiting factors with consistent powder and process characterization along with process control.

  2. Manufacturing of transparent ZnS ceramics by powders sintering

    NASA Astrophysics Data System (ADS)

    Merdrignac-Conanec, O.; Hakmeh, N.; Durand, G.; Zhang, X.-H.

    2016-05-01

    We report the use of the low cost hot-pressing technique to produce ZnS for multispectral operation, from visible up to 12 μm. Considerable progress has been obtained by developing efficient precipitation and combustion powders synthesis procedures. The main emphasis has been on the elaboration of ZnS precursor powders with controlled morphology/chemical composition to reduce extrinsic scattering and impurities. We were able to produce ZnS parts with visible transparency and transmission in the 8-12 μm range that is comparable to that of CVD ZnS. The correlation of processing variables with powders sinterability and optical transmission of the HPed ceramics is discussed.

  3. A simple procedure to prepare spherical {alpha}-alumina powders

    SciTech Connect

    Liu Hongyu; Ning Guiling Gan Zhihong; Lin Yuan

    2009-04-02

    Spherical {alpha}-alumina powders were prepared by the controlled hydrolysis of aluminum isopropoxide in a hydrolysis system consisting of octanol and acetonitrile. Diverse solvents to dissolve reactant formed diverse hydrolysis systems and affected particle shape of {alpha}-alumina powders. The precursors crystallized to {gamma}-alumina at 1000 deg. C and converted to {alpha}-alumina at 1150 deg. C without intermediate phases. The particle morphology of precursor was retained after it crystallized to {alpha}-alumina. The heating rate influenced the particle shape and the state of agglomeration during calcination process. The thermal properties of the precursors were characterized by thermal gravimetric and differential thermal analysis. X-ray diffraction technique was used to confirm the conversion of crystalline phase of alumina powders from amorphous to {alpha}-phase. Transmission electron microscopy was used to investigate the morphologies and size of the precursors and products.

  4. 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...

  5. Detection and characterization of smokeless powders with ion mobility spectrometry

    NASA Astrophysics Data System (ADS)

    Hernandez, Neiza M.; Rosario, Santa V.; Hernandez, Samuel P.; Mina, Nairmen

    2005-05-01

    Smokeless Powders are a class of propellants that were developed in the late 19th century to replace black powder; it has been used as an explosive in shotguns, rifles, firearms and many other larger caliber weapons. These propellants can be placed into one of three different classes according to the chemical composition of their primary energetic ingredients. Advance equipment have been designed and used for the detection of explosives devices and compounds potentially energetic. In this research we are developing an analytical methodology to detect different formulation of smokeless powders: Alliant-American Select, Alliant-Bullseye, and Alliant-Red Dot using the ion mobility spectrometry (IMS) technique. We used different surfaces like computer diskettes, CD"s, book covers and plastics to study their adsorption/desorption process. Using micropipettes, we delivered solutions with different amounts of Smokeless Powders from a 1000 ppm solution and deposit it on various types of filters to make a calibration curve. Several amounts of Smokeless Powder were deposited to the different surfaces and collected with filter paper. The samples were desorbed directly from the filter to the instrument inlet port. Subsequently, the percentage of explosive recovered was calculated.

  6. Optimisation of powders for pulmonary delivery using supercritical fluid technology.

    PubMed

    Rehman, Mahboob; Shekunov, Boris Y; York, Peter; Lechuga-Ballesteros, David; Miller, Danforth P; Tan, Trixie; Colthorpe, Paul

    2004-05-01

    Supercritical fluid technology exploited in this work afforded single-step production of respirable particles of terbutaline sulphate (TBS). Different crystal forms of TBS were produced consistently, including two polymorphs, a stoichiometric monohydrate and amorphous material as well as particles with different degrees of crystallinity, size, and morphology. Different solid-state and surface characterisation techniques were applied in conjunction with measurements of powder flow properties using AeroFlow device and aerosol performance by Andersen Cascade Impactor tests. Improved fine particle fraction (FPF) was demonstrated for some powders produced by the SCF process when compared to the micronised material. Such enhanced flow properties and dispersion correlated well with the reduced surface energy parameters demonstrated by these powders. It is shown that semi-crystalline particles exhibited lower specific surface energy leading to a better performance in the powder flow and aerosol tests than crystalline materials. This difference of the surface and bulk crystal structure for selected powder batches is explained by the mechanism of precipitation in SCF which can lead to surface conditioning of particles produced. PMID:15113578

  7. Fine tuning the roughness of powder blasted surfaces

    NASA Astrophysics Data System (ADS)

    Wensink, Henk; Schlautmann, Stefan; Goedbloed, Martijn H.; Elwenspoek, Miko C.

    2002-09-01

    Powder blasting (abrasive jet machining) has recently been introduced as a bulk-micromachining technique for brittle materials. The surface roughness that is created with this technique is much higher (with a value of Ra between 1-2.5 μm) compared to general micromachining techniques. In this paper we study the roughness of powder blasted glass surfaces, and show how it depends on the process parameters. The roughness can also be changed after blasting by HF etching or by using a high-temperature anneal step. Roughness measurements and scanning electron microscopy images show the quantitative and qualitative changes in roughness. These post-processes will allow us to investigate the influence of surface roughness on the microsystem performance in future research.

  8. Polymer quenched prealloyed metal powder

    DOEpatents

    Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

    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.

  9. Surface free energy characterization of powders

    NASA Astrophysics Data System (ADS)

    Yildirim, Ismail

    2001-12-01

    Microcalorimetric measurements and contact angle measurements were conducted to study the surface chemistry of powdered minerals. The contact angle measurements were conducted on both flat and powdered talc samples, and the results were used to determine the surface free energy components using Van Oss-Chaudhury-Good (OCG) equation. It was found that the surface hydrophobicity of talc increases with decreasing particle size. At the same time, both the Lifshitz-van der Waals (gammasLW) and the Lewis acid-base (gammas AB) components (and, hence, the total surface free energy (gammas)) decrease with decreasing particle size. Heats of immersion measurements were conducted using a flow microcalorimeter on a number of powdered talc samples. The results were then used to calculate the contact angles using a rigorous thermodynamic relation. The measured heat of immersion values in water and calculated contact angles showed that the surface hydrophobicity of talc samples increase with decreasing particle size, which agrees with the direct contact angle measurements. The microcalorimetric and direct contact angle measurements showed that acid-base interactions play a crucial role in the interaction between talc and liquid. Using the Van Oss-Chaudhury-Good's surface free energy components model, various talc powders were characterized in terms of their acidic and basic properties. It was found that the magnitude of the Lewis electron donor, gamma s-, and the Lewis electron acceptor, gamma s+, components of surface free energy is directly related to the particle size. The heats of adsorption of butanol on various talc samples from n-heptane solution were also determined using a flow microcalorimeter. It was found that the total surface free energy (gammas) at the basal plane surface of talc is much lower than the total surface free energy at the edge surface. Furthermore, the effects of the surface free energies of solids during separation from each other by flotation and

  10. Synthesis, Growth, Spectral and Optical Properties of Glycinyl Urea Single Crystal

    SciTech Connect

    Shanthi, N. Theresita; Selvarajan, P.; Rose, A. S. J. Lucia

    2011-10-20

    Single crystals of Glycinyl Urea were grown from aqueous solution by slow evaporation technique at room temperature. The cell parameters of the grown crystals were estimated by Single X-ray diffraction studies. The functional groups present in the grown crystals were ascertained using FTIR spectrum analysis. UV-visible transmittance spectrum was recorded to study the optical transparency of the grown crystal. The non-linear optical property has been tested by Kurtz powder technique.

  11. Fe-nanoparticle coated anisotropic magnet powders for composite permanent magnets with enhanced properties

    NASA Astrophysics Data System (ADS)

    Marinescu, M.; Liu, J. F.; Bonder, M. J.; Hadjipanayis, G. C.

    2008-04-01

    Utilizing the chemical reduction of FeCl2 with NaBH4 in the presence of 2:17 Sm-Co powders, we synthesized composite Sm(Co0.699Fe0.213Cu0.064Zr0.024)7.4/nano-Fe anisotropic hard magnetic powders. The average particle size of the hard magnetic core powder was 21μm while the soft magnetic Fe nanoparticles deposited uniformly on the core powder had a particle size smaller than 100nm. Different reaction protocols, such as immersion of the hard magnetic core powder in each reagent, the use of microemulsion (micelle) technique, or doubling the weight ratio of FeCl2 to core powder, led to different degrees of magnetic coupling of the hard and soft magnetic components of the composite powder. A reaction time of 180s led to deposition of 3.5wt% Fe nanoparticles and improved magnetic properties of the composite powder compared to the uncoated Sm(Co0.699Fe0.213Cu0.064Zr0.024)7.4 powder. The respective magnetic hysteresis parameters were 4πM18kOe=11.3kG, 4πMr=11kG, and Hci>20kOe with a smooth demagnetization curve.

  12. Chemical and Physical Properties of Tantalum Powder

    NASA Astrophysics Data System (ADS)

    Purushotham, Y.; Balaji, T.; Kumar, Arbind; Govindaiah, R.; Sharma, M. K.; Sethi, V. C.; Prakash, T. L.

    The present work is intended to produce capacitor grade Tantalum powder by sodium reduction of potassium tantalum fluoride prepared from an indigenous ore source. The powder has been characterized for its chemical and physical properties, and compared with the commercially available powders. It is found that indigenous powder has higher impurity levels which could, however, be reduced to acceptance limits. The average particle size is within the prescribed limits.

  13. Container Prevents Oxidation Of Metal Powder

    NASA Technical Reports Server (NTRS)

    Woodford, William H.; Power, Christopher A.; Mckechnie, Timothy N.; Burns, David H.

    1992-01-01

    Sealed high-vacuum container holds metal powder required free of contamination by oxygen from point of manufacture to point of use at vacuum-plasma-spraying machine. Container protects powder from air during filling, storage, and loading of spraying machine. Eliminates unnecessary handling and transfer of powder from one container to another. Stainless-steel container sits on powder feeder of vacuum-plasma-spraying machine.

  14. Method for synthesizing ultrafine powder materials

    DOEpatents

    Buss, Richard J.; Ho, Pauline

    1988-01-01

    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.

  15. Structural Color Painting by Rubbing Particle Powder

    PubMed Central

    Park, ChooJin; Koh, Kunsuk; Jeong, Unyong

    2015-01-01

    Structural colors originate from purely physical structures. Scientists have been inspired to mimic the structures found in nature, the realization of these structures still presents a great challenge. We have recently introduced unidirectional rubbing of a dry particle powder on a rubbery surface as a quick, highly reproducible means to fabricate a single crystal monolayer assembly of particles over an unlimited area. This study extends the particle-rubbing process to a novel fine-art painting, structural color painting (SCP). SCP is based on structural coloring with varying iridescence according to the crystal orientation, as controlled by the rubbing direction. This painting technique can be applied on curved surfaces, which enriches the objects to be painted and helps the painter mimic the structures found in nature. It also allows for quick fabrication of complicated particle-assembly patterns, which enables replication of paintings. PMID:25661669

  16. Structural Color Painting by Rubbing Particle Powder

    NASA Astrophysics Data System (ADS)

    Park, Choojin; Koh, Kunsuk; Jeong, Unyong

    2015-02-01

    Structural colors originate from purely physical structures. Scientists have been inspired to mimic the structures found in nature, the realization of these structures still presents a great challenge. We have recently introduced unidirectional rubbing of a dry particle powder on a rubbery surface as a quick, highly reproducible means to fabricate a single crystal monolayer assembly of particles over an unlimited area. This study extends the particle-rubbing process to a novel fine-art painting, structural color painting (SCP). SCP is based on structural coloring with varying iridescence according to the crystal orientation, as controlled by the rubbing direction. This painting technique can be applied on curved surfaces, which enriches the objects to be painted and helps the painter mimic the structures found in nature. It also allows for quick fabrication of complicated particle-assembly patterns, which enables replication of paintings.

  17. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  18. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  19. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  20. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  1. 21 CFR 73.1645 - Aluminum powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum....

  2. 21 CFR 73.2645 - Aluminum powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements...

  3. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic...

  4. 30 CFR 57.6133 - Powder chests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available at MSHA, 1100 Wilson Blvd... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Powder chests. 57.6133 Section 57.6133 Mineral... § 57.6133 Powder chests. (a) Powder chests (day boxes) shall be— (1) Structurally sound,...

  5. 30 CFR 57.6133 - Powder chests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available at MSHA, 1100 Wilson Blvd... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Powder chests. 57.6133 Section 57.6133 Mineral... § 57.6133 Powder chests. (a) Powder chests (day boxes) shall be— (1) Structurally sound,...

  6. 30 CFR 57.6133 - Powder chests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies are available at MSHA, 1100 Wilson Blvd... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Powder chests. 57.6133 Section 57.6133 Mineral... § 57.6133 Powder chests. (a) Powder chests (day boxes) shall be— (1) Structurally sound,...

  7. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Copper powder. 73.1647 Section 73.1647 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine...

  8. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Black powder. 56.6901 Section 56.6901 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives General Requirements § 56.6901 Black powder. (a) Black powder...

  9. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Black powder. 56.6901 Section 56.6901 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives General Requirements § 56.6901 Black powder. (a) Black powder...

  10. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic...