Sample records for kurtz powder technique

  1. Blackboard VistaBlackboard Vista Presenter: Jeff KurtzPresenter: Jeff Kurtz

    E-print Network

    Blackboard VistaBlackboard Vista Presenter: Jeff KurtzPresenter: Jeff Kurtz itsinfo''s studentss students #12;LMS BenefitsLMS Benefits #12;What canWhat can Blackboard VistaBlackboard Vista do@tamu.eduits@tamu.edu, 862, 862--39773977 #12;Q&AQ&A Questions?Questions? #12;Blackboard VistaBlackboard Vista Presenter

  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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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. Application of physical and chemical characterization techniques to metallic powders

    SciTech Connect

    Slotwinski, J. A. [Intelligent Systems Division, Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States); Watson, S. S.; Stutzman, P. E.; Ferraris, C. F.; Peltz, M. A.; Garboczi, E. J. [Materials and Structural Systems Division, Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899 (United States)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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. (Brownsboro, AL); Antony, Leo V. M. (Huntsville, AL); O'Dell, Scott (Arab, AL); Power, Chris (Guntersville, AL); Tabor, Terry (Huntsville, AL)

    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. Complex Permittivity of Powder Metal Compacts by Cavity Perturbation Technique

    NASA Astrophysics Data System (ADS)

    Lynch, Chris; Johnson, Earnie; Ma, Junkun; Miskovsky, Nicholas; Weisel, Gary; Weiss, Brock; Zimmerman, Darin

    2006-03-01

    We present measurements of the complex permittivity of powder metal compacts using microwave cavity perturbation techniques. Using a 2.45GHz, TM010 microwave cavity operating in conjunction with a vector network analyzer, we have systematically measured the real (?') and imaginary (?'') parts of the effective complex permittivity of pure, powder metal, cylindrical samples (0.25in by 0.25in). By placing these in the electric-field antinode, the dielectric properties at microwave frequencies are obtained by comparison with the expected change in the cavity Q by perturbation theory. We have studied the effect of varying particle size and green density as means to understand the absorption and heating of powdered metals in microwave fields. We acknowledge the additional work of undergraduates Kelly Martin and Charles Smith, who assisted in the setup of experimental apparatus, sample preparation, and data acquisition.

  9. Comparative study of doped ceria thin-film electrolytes prepared by wet powder spraying with powder synthesized via two techniques

    Microsoft Academic Search

    Huangang Shi; Wei Zhou; Ran Ran; Zongping Shao

    2010-01-01

    Fabrication of dense Sm0.2Ce0.8O1.9 (SDC) thin-film electrolytes by wet powder spraying in combination with high-temperature sintering is investigated. Two powder synthesis techniques, i.e., a hydrothermal synthesis and an EDTA–citrate complexing sol–gel process, were investigated. X-ray diffraction, BET surface area and laser particle size analysis demonstrate there is certain level of aggregation in both powders. However, it is more pronounced in

  10. Novel technique for grain refinement in aluminum casting by Al–Ti–B powder injection

    Microsoft Academic Search

    C. Limmaneevichitr; W. Eidhed

    2003-01-01

    This paper purposes a novel technique for grain refinement in Al casting by Al–Ti–B powder injection into molten Al. Al–Ti–B powders were made by soaking ribbons, obtained from drilling an Al–Ti–B grain refiner bar, in liquid nitrogen before grinding them into small powders. A simple device for this technique comprises a small hopper to store Al–Ti–B powders, a ball valve

  11. Influence of raw powder preparation routes on properties of hydroxyapatite fabricated by 3D printing technique

    Microsoft Academic Search

    J. Suwanprateeb; R. Sanngam; T. Panyathanmaporn

    2010-01-01

    A comparison between two routes of raw powder preparation, namely spray drying and grinding, for 3D printing of hydroxyapatite was carried out. Hydroxyapatite particles prepared by the spray drying technique were spherical in shape whereas the grinding route gave irregular-shaped agglomerates. Spray-dried powders had higher tap density than milled powders, however milled powders yielded 3DP specimens with greater green density

  12. Checklists for powder inhaler technique: a review and recommendations.

    PubMed

    Basheti, Iman A; Bosnic-Anticevich, Sinthia Z; Armour, Carol L; Reddel, Helen K

    2014-07-01

    Turbuhaler and Diskus are commonly used powder inhaler devices for patients with respiratory disease. Their effectiveness is limited in part by a patient's ability to use them correctly. This has led to numerous studies being conducted over the last decade to assess the correct use of these devices by patients and health care professionals. These studies have generally used device-specific checklists to assess technique, this being the most feasible and accessible method for assessment. However, divergence between the checklists and scoring systems for the same device in different studies makes direct comparison of results difficult and at times inappropriate. Little evidence is available to assess the relative importance of different criteria; however, brief patient training based on specific inhaler technique checklists leads to significant improvement in asthma outcomes. This paper reviews common checklists and scoring systems used for Turbuhaler and Diskus, discusses the problem of heterogeneity between different checklists, and finally recommends suitable checklists and scoring systems for these devices based on the literature and previous findings. Only when similar checklists are used across different research studies will accurate comparisons and meta-analysis be possible. PMID:24129338

  13. Manufacturing technique of Nb 3Al super-conductive sheet by electrically heated powder rolling

    NASA Astrophysics Data System (ADS)

    Mochizuki, C.; Mikami, M.

    The conventional manufacturing processes of superconductive wires or sheets are complex. Nb 3Al is a well-known superconductive material. Nb 3Al could be produced from powder directly by an advanced powder rolling technique. The experimental apparatus is composed of a powder rolling mill within a vacuum chamber and a direct current power supply unit. Powder is supplied into the roll gap and heated by applying electricity during rolling. The method is called `electrically heated powder rolling'. Nb-25.4Al (mol%) powder of which particle size was under 0.15 mm was prepared by plasma melt gas atomizing (PMGA) technique. The powder consists of super-saturated solid solution of Nb and Al. But after electrically heated powder rolling, the existence of Nb 3Al (A15) phase was confirmed by X-ray diffraction. The sheet was porous and the thickness was about 0.7 mm. The sheet was re-rolled to the thickness of about 0.5 mm, then pore of the sheet was eliminated. The resistivity of the re-rolled sheet was measured at lower temperature than RT and Tc (0) of 15 K was confirmed. It is believed that electrically heated powder rolling is effective manufacturing technique for superconductive sheet such as intermetallic compounds.

  14. Needle-Free Delivery of Powdered Protein Vaccines: A New and Rapidly Developing Technique

    Microsoft Academic Search

    Andreas S. Ziegler

    2008-01-01

    Skin is an attractive tissue for vaccine delivery. Recently, interest has focused on dry powder injectors for needle-free\\u000a vaccination. This review summarizes the current knowledge on this innovative application technique.

  15. Novel powder metallurgy technique for development of Fe–P-based soft magnetic materials

    Microsoft Academic Search

    Jiten Das; K. Chandra; P. S. Misra; B. Sarma

    2008-01-01

    Novel powder metallurgy technique (hot forging technique) is used for the development of high-density Fe–P-based soft magnetic alloys such as Fe–P binary, Fe–P–Cr ternary and Fe–P–Cr–Si quaternary alloys. In this process, mild steel encapsulated powders were hot forged into slabs, hot rolled and annealed to relieve the residual stresses. These alloys were subjected to in-house characterization, e.g. density and theoretically

  16. 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.

  17. Synthesis and characterization of zinc titanate nano-crystal powders by sol–gel technique

    Microsoft Academic Search

    Yee-Shin Chang; Yen-Hwei Chang; In-Gann Chen; Guo-Ju Chen; Yin-Lai Chai

    2002-01-01

    A sol–gel technique including the Pechini process has been employed for the preparation of nano-sized zinc titanate (ZnTiO3) powders. The yielding powders were heated at temperature from 500°C to 1000°C for various times. The ZnTiO3 phase was formed at the beginning of 500°C. The shape of crystalline will be changed from granular to fiber as the calcination temperature increasing from

  18. Flowability measurements of pharmaceutical powder mixtures with poor flow using five different techniques.

    PubMed

    Lindberg, Nils-Olof; Pålsson, Magnus; Pihl, Ann-Christin; Freeman, Reg; Freeman, Tim; Zetzener, Harald; Enstad, Gisle

    2004-08-01

    Four different tablet formulations for direct compression with poor flow properties were tested regarding flowability using five different techniques: Hausner ratio, avalanching behavior, powder rheometer, uniaxial tester, and Jenike tester. In addition, the behavior of three of the formulations during emptying of the mixer and tableting was observed and compared to the results of the flowability measurements. The rank order correlation of the formulations was generally the same with all techniques. The flow properties measured by the different techniques reflected the behavior during processing of the powder mixtures. PMID:15491056

  19. New processing technique for DEB powder for thermal batteries

    SciTech Connect

    Szwarc, R.; Walton, R.D.

    1980-06-01

    The purpose of this paper is to explore how material processing influences thermal battery performance, and how battery performance can be improved by changes in processing. This discussion is confined to the class of thermal batteries designed by Sandia Laboratories and built under the supervision of General Electric in St. Petersburg, Florida. The electrochemical system employed is: Ca/LiCl-KCl-CaCrO/sub 4//Fe. These batteries are primary reserve batteries which employ a pelletized cell design. Each cell consists of an electrolyte-depolarizer pellet sandwiched between an anode and a heat pellet. The anode employed may be one of two forms: sheet calcium disc, mechanically attached to an iron or steel backing; or a substrate disc of iron or steel on which 3 to 5 mils of calcium had been evaporated. The depolarizer-electrolyte, commonly referred to as DEB, is composed of CaCrO/sub 4/, LiCl-KCl eutectic and SiO/sub 2/ binder powder, which has been blended and pressed into pellets. The DEB pellet serves as electrolyte and as active cathode when the salt becomes molten upon battery activation. The heat pellet serves the dual purpose of providing the heat necessary to activate the battery and as the cathode current collector. The heat pellet is composed of iron powder and KClO/sub 4/. A battery is made up of one or more stacks of about 12 cells connected in series to produce a voltage of 28 to 32 volts. Since activated life requirements for batteries vary from seconds up to one hour, the battery must be well insulated to conserve the heat produced by the ignition of the heat pellets to maintain the electrolyte in a molten state. This insulation is also important to protect sensitive electronic components in contact with the battery case. Because the electrolyte, particularly LiCl, is hygroscopic, the batteries are hermetically sealed in stainless steel cans, and are manufactured in dryrooms maintained at 3% relative humidity or better.

  20. CHARACTERIZATION AND PROPERTIES OF ALUMINUM COMPOSITE MATERIALS PREPARED BY POWDER METALLURGY TECHNIQUES USING CERAMIC SOLID WASTES

    Microsoft Academic Search

    L. Ma. Flores-Vélez; J. Chávez; L. Hernández; O. Domínguez

    2001-01-01

    This work provides preliminary results of aluminum metal matrix composites (MMCs) reinforced with granulated slag (GS) and electric arc furnace dust (EAFD). The present work concerns the synthesis and properties of Al\\/GS and Al\\/EAFD composites based on powder metallurgy techniques. The hardness and compressive strength of the sintering compacts were determined to compare the mechanical properties of the composite material

  1. Application of new synchrotron powder diffraction techniques to anomalous scattering from glasses

    SciTech Connect

    Beno, M.A.; Knapp, G.S.; Armand, P.; Price, D.L.; Saboungi, M. (Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States))

    1995-02-01

    We have applied two synchrotron powder diffraction techniques to the measurement of high quality anomalous scattering diffraction data for amorphous materials. One of these methods, which uses a curved perfect crystal analyzer to simultaneously diffract multiple powder lines into a position sensitive detector has been shown to possess high resolution, low background, and very high counting rates. This data measurement technique provides excellent energy resolution while minimizing systematic errors resulting from detector nonlinearity. Anomalous scattering data for a Cesium Germanate glass collected using this technique will be presented. The second powder diffraction technique uses a flat analyzer crystal to deflect multiple diffraction lines out of the equatorial plane. Calculations show that this method possesses sufficient energy resolution for anomalous scattering experiments when a perfect crystal analyzer is used and is experimentally much simpler. Future studies will make use of a rapid sample changer allowing the scattering from the sample and a standard material (a material not containing the anomalous scatterer) to be measured alternately at each angle, reducing systematic errors due to beam instability or sample misalignment.

  2. Application of new synchrotron powder diffraction techniques to anomalous scattering from glasses

    SciTech Connect

    Beno, M.A.; Knapp, G.S.; Armand, P.; Price, D.L.; Saboungi, M.L.

    1994-08-01

    The authors have applied two synchrotron powder diffraction techniques to the measurement of high quality anomalous scattering diffraction data for amorphous materials. One of these methods, which uses a curved perfect crystal analyzer to simultaneously diffract multiple powder lines into a position sensitive detector has been shown to possess high resolution, low background and very high counting rates. This data measurement technique provides excellent energy resolution while minimizing systematic errors resulting from detector non-linearity. Anomalous scattering data for a cesium germanate glass collected using this technique will be presented. The second powder diffraction technique uses a flat analyzer crystal to deflect multiple diffraction lines out of the equatorial plane. Calculations show that this method possesses sufficient energy resolution for anomalous scattering experiments when a perfect crystal analyzer is used and is experimentally much simpler. Future studies will make use of a rapid sample changer allowing the scattering from the sample and a standard material (a material not containing the anomalous scatterer) to be measured alternately at each angle, reducing systematic errors due to beam instability or sample misalignment.

  3. Development of novel carbon nanotube reinforced magnesium nanocomposites using the powder metallurgy technique

    Microsoft Academic Search

    C S Goh; J Wei; L C Lee; M Gupta

    2006-01-01

    Carbon nanotube (CNT) reinforced magnesium was synthesized using the powder metallurgy technique followed by hot extrusion. Up to 0.3wt% of CNTs were added as reinforcements. The effects of the carbon nanotubes on the physical and mechanical properties of Mg were investigated. The thermo-mechanical property results show an increase in thermal stability with increasing amount of CNTs in the Mg nanocomposites.

  4. Lifting techniques for finger marks on human skin previous enhancement by Swedish Black powder — A preliminary study

    Microsoft Academic Search

    Matej Trapecar

    2009-01-01

    An examination was done to investigate whether certain lifting techniques can lift recovered latent fingerprints on human skin surfaces of living subjects. For recovery Swedish Soot powder mixture (Swedish Black) was used.Donors intentionally placed fingerprints on the skin surface of living subjects. Finger marks were then in all cases recovered with Swedish Black powder. The procedure was repeated after 1 h

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

    SciTech Connect

    Wattanasiriwech, Darunee [School of Science, Mae Fah Luang University, Chiangrai 57100 (Thailand)]. E-mail: darunee@mfu.ac.th; Wattanasiriwech, Suthee [School of Science, Mae Fah Luang University, Chiangrai 57100 (Thailand); Stevens, Ron [Department of Engineering and Applied Science, University of Bath (United Kingdom)

    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.

  6. Investigation of the structure of ettringite by time-of-flight neutron powder diffraction techniques

    SciTech Connect

    Hartman, M.R. [University of Michigan, Ann Arbor, MI 48109 (United States)]. E-mail: michael.hartman@nist.gov; Berliner, R. [University of Michigan, Ann Arbor, MI 48109 (United States)

    2006-02-15

    The crystalline structure of ettringite, Ca{sub 6}[Al(OH){sub 6}]{sub 2}(SO{sub 4}){sub 3}.{approx}26H{sub 2}O, was investigated using high-resolution time-of-flight neutron powder diffraction techniques. The powder diffraction data were subjected to Rietveld crystal structure refinement. The resultant ettringite crystal structure confirmed the positions of Ca, Al, and S atoms while permitting a more precise determination of the locations of O and H atomic positions than in previous X-ray and neutron diffraction studies. A discussion of the ettringite hydrogen bonding network is presented, illustrating the role of hydrogen bonding in the stabilization of the ettringite structure.

  7. [Influence of particle sizes and content of effective compositions of Panax notoginseng powders crashing by superfine somminution technique].

    PubMed

    Wang, Yan-Ping; Liu, Yu-Ling; Yang, Li-Xin; Xu, Ya; Zhao, Li; Zhang, Xiao-Li; Li, Hui

    2014-04-01

    In this study, superfine comminution technique was applied to destroy the cell wall of the Panax notoginseng, and then the influence of the particle sizes and the content of effective composition of the P. notoginseng powders were learned, comparing with the common powders. Superfine comminution technique was used for 0.5, 1, 1.5, 2 h, respectively and the particle sizes, unifirmity were regarded as the evaluation index. Then, the sizes of the powders was measured that were crashed with different time by Malvern Mastersizer 2000 + Scricco 2000 and the total content of ginsenoside Rg1, ginsenoside Rb1, notoginsenoside R1 in the superfine powder of P. notoginseng were determined by HPLC-ELSD. Finally, the powder that crashed for two hours possess the more uniform in sizes that is at cell level, D50 is about 9.599 microm, the size distribution was presented as one peak, the other three samples were two peaks. The total content of the three saponins in the four samples that crashed for 0.5, 1, 1.5, 2 h by superfine comminution technique were 7.7%, 7.5%, 7.5%, 8.3%. However, the total content of the three ingredients in the common powder was 5.0%. This investigation indicated that superfine comminution technique has remarkable effect on particle size and uniformity of the common powder of P. notoginseng. By comparing the superfine powder and common powder, it was found that the method obviously improved the total content of the saponins and provided a basis for reducing dosage of notoginseng in clinical application, but the content and the crashed time were not the linear relationship. The crashed time can be chosen by combining with the demand partical sizes in the production. PMID:25039177

  8. Toward a Process-Based Framework for Classifying Personality Tests: Comment on Meyer and Kurtz (2006)

    Microsoft Academic Search

    Robert F. Bornstein

    2007-01-01

    Meyer and Kurtz (2006) argued that the longstanding psychological test labels “objective” and “projective” have outlived their usefulness, and invited further work focusing on alternative terms for these measures. This Comment describes a framework for classifying personality tests based on the psychological processes that occur as people respond to test stimuli. Because an attribution process is involved in responding to

  9. A review of the hybrid techniques for the fabrication of hard magnetic microactuators based on bonded magnetic powders

    NASA Astrophysics Data System (ADS)

    Pallapa, M.; Yeow, J. T. W.

    2015-02-01

    Polymer composites based on permanent magnetic bonded powders exhibit immense potential for applications in microactuators and sensors with magnetic performances comparable to their fully dense counterparts. While fabrication and integration of magnetic devices based on bonded magnetic powders is challenging via conventional deposition and electrochemical growth techniques, hybrid fabrication offers a promising alternative. This paper presents the evolution of permanent magnetic materials into bonded magnetic powders, the magnetic performance figures of merit of permanent magnetic materials significant for the design and manufacture of polymer based sensors and actuators. A review of the hybrid fabrication techniques such as replica molding, squeegee coating, spin casting etc are reported. Critical factors affecting the fabrication of polymer magnetic composites such as filler particle size and effect of magnetic field during fabrication are discussed. Prior art based on polymer magnetic composites for the fabrication of hard magnetic films and hard magnetic actuators are presented.

  10. Predicting caking behaviors in powdered foods using a low-field nuclear magnetic resonance (NMR) technique

    Microsoft Academic Search

    Myong-Soo Chung; Roger Ruan; Paul Chen; Jin-Ho Kim; Tae-Hoi Ahn; Chang-Kyu Baik

    2003-01-01

    This study is concerned with caking of powder mixes. Our previous study tied the caking process to the nuclear magnetic resonance (NMR) spin–spin (T2) relaxation characteristics exhibited by powder ingredients subjected to temperature scan from –20°C to 110°C (Journal of Food Science 65 (1) (2000) 134). Four temperature–T2 curve patterns were identified, each of which represents a group of powder

  11. Synthesis of MgNb 2 O 6 nanocrystalline powders by an improved citrate sol–gel technique

    Microsoft Academic Search

    YingChun Zhang; XiangNa Zhou; Xiu Wang

    2009-01-01

    MgNb2O6 nanocrystalline powders have been synthesized at a low temperature by improved citrate sol–gel method in this paper. The\\u000a high quality solution of Nb5+ was prepared using Nb2O5 as the starting material. The crystal structure and microstructure of MgNb2O6 powders were characterized by XRD and SEM techniques, and the effects of preparation craft including pH value and the proportion\\u000a of

  12. Characterization of Fine Powders

    NASA Astrophysics Data System (ADS)

    Krantz, Matthew; Zhang, Hui; Zhu, Jesse

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

  13. Copper matrix SiC and Al 2O 3 particulate composites by powder metallurgy technique

    Microsoft Academic Search

    S. F Moustafa; Z Abdel-Hamid; A. M Abd-Elhay

    2002-01-01

    Copper matrix reinforced with either Ni-coated or uncoated SiC and Al2O3 particulate composites were made by means of the powder metallurgy route. The reinforcement particles of SiC and Al2O3 were coated with a thin layer of nickel by electroless method. The coated or uncoated reinforcement particles of either SiC or Al2O3 were added to copper metal powders with nominal loading

  14. 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

  15. Applications of capsule dosing techniques for use in dry powder inhalers.

    PubMed

    Edwards, David

    2010-07-01

    Dry powder inhaler (DPI) devices that utilize two-piece capsules as the dose-holding system can require specialized dosing equipment to fill the capsules. Such products are known as 'premetered' because they contain previously measured doses in a dose carrier (the capsule). The capsule is either inserted into the device during manufacture or by the patient prior to use. The dose is inhaled directly from the device/premetered unit by the patient. Regardless of DPI design, the most crucial attributes are the reproducibility of the discharged dose and the particle size distribution of the drug within that dose. Filling inhalation powders into capsules often requires specialized equipment in order to handle the very low weights that are often contained in each dose. The equipment typically needs to incorporate in-process checks to confirm the filling process has been correctly performed, with the ability to reject any under- or over-filled capsules, in line with established quality criteria. In the majority of cases, such processing equipment is maintained in a temperature and humidity controlled environment to avoid moisture uptake and potential powder aggregation and, in particular, to ensure the powder is free flowing on introduction into the capsule. This ensures that the emitted dose is maximized and controlled according to industry guidelines and that the fine particle fraction provides an optimum clinical benefit. Several methods of dosing precise doses of powder into capsules are available and include dosator technology and tamp processes, as well as equipment that utilize the 'pepper-shaker' or 'pepper-pot' principle for the accurate dispensing of powders. This article reviews the suitability of each method with respect to dosing inhalation powder into capsules for use in DPI devices, and discusses why the pepper-pot principle could offer a number of clear benefits. PMID:22816126

  16. Capreomycin inhalable powders prepared with an innovative spray-drying technique.

    PubMed

    Schoubben, Aurélie; Giovagnoli, Stefano; Tiralti, Maria Cristina; Blasi, Paolo; Ricci, Maurizio

    2014-07-20

    The aim of the work was to produce inhalable capreomycin powders using a novel spray-drying technology. A 2(3) factorial design was used to individuate the best working conditions. The maximum desirability was identified at the smallest mean volume diameter (dv) and span, and the highest yield. Powders were characterized for size, morphology, flowability and aerodynamic properties. Mathematical models showed a good predictivity with biases lower than 20%. The maximum conformity with desirability criteria was obtained spraying a 10mg/mL bacitracin solution at 111 °C with the 4 ?m pore size membrane. By processing capreomycin sulfate with the parameters optimized for bacitracin, an inhalable powder was obtained (i.e., yield of 82%, dv of 3.83 ?m, and span of 1.04). By further optimization, capreomycin sulfate powder characteristics were improved (i.e., yield, ?71%; dv, 3.25 ?m; span, 0.95). After formulation with lactose, emitted dose and respirable fraction of 87% and ?27% were obtained, respectively. Two capreomycin sulfate powders with suitable properties for inhalation were produced using the nano spray-dryer B-90. PMID:24747443

  17. 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.

  18. 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

  19. 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.

  20. Lifting techniques for finger marks on human skin previous enhancement by Swedish Black powder--a preliminary study.

    PubMed

    Trapecar, Matej

    2009-12-01

    An examination was done to investigate whether certain lifting techniques can lift recovered latent fingerprints on human skin surfaces of living subjects. For recovery Swedish Soot powder mixture (Swedish Black) was used. Donors intentionally placed fingerprints on the skin surface of living subjects. Finger marks were then in all cases recovered with Swedish Black powder. The procedure was repeated after 1 h and 4 h. Treated finger marks were secured and preserved as latent fingerprint evidence by different lifting processes. Having examined skin surfaces and finger marks we observed that the lifters such as white instant lifter, white fingerprint gelatin, black fingerprint gelatin, silicone, transparent adhesive tape, are suitable. Moreover, white fingerprint gelatin and white instant lifter proved to be very good at lifting treated finger marks. Black fingerprint gelatin was very good also, but finger marks were examined by slant light. PMID:20120609

  1. Comparison of the Efficiency of the One and Two-Step Process for the Production of BSCCO (2212) Powders by Means of Analytical Techniques

    Microsoft Academic Search

    Maria Ochsenkühn-Petropoulou; Rachel Argyropoulou; Klaus-Michael Ochsenkühn

    2000-01-01

    .  ?The efficiency of the production of the high temperature superconducting powders Bi2Sr2CaCu2O8+x (BSCCO 2212) using the solid state reaction in one or two step processes under different thermal treatment was compared by\\u000a means of different modern analytical techniques. Through the same techniques the optimization of the production of the production\\u000a of Bi-2212 powder produced by the two step process, was

  2. Recent development in the fabrication of metal matrix-particulate composites using powder metallurgy techniques

    Microsoft Academic Search

    Y. B. Liu; S. C. Lim; L. Lu; M. O. Lai

    1994-01-01

    It is advantageous to fabricate metal matrix-particulate composites (MMPCs) using powder metallurgy (PM) because the fabricated composites possess a higher dislocation density, a small sub-grain size and limited segregation of particles, which, when combined, result in superior mechanical properties. The various PM-related processes currently in use in the fabrication of MMPCs, are reviewed, outlining the common problems encountered in each

  3. Hydroxyapatite powders and thin films prepared by a sol-gel technique

    Microsoft Academic Search

    C. M. Lopatin; V. Pizziconi; T. L. Alford; T. Laursen

    1998-01-01

    The formation of hydroxyapatite (HA) from a sol-gel precursor was studied using X-ray diffraction (XRD). The sol-gel was processed into both powders and thin films. The effect of drying and firing temperatures on the HA phase formation was studied. Thin HA films up to 1 ?m thick were deposited on silicon wafers coated either with borophosphate silicate glass (BPSG) or

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

    PubMed

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

    2015-03-01

    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 methods will become crucially important in the near future. PMID:25866663

  5. Effect of pyrolysis temperature on structural, microstructural and optical properties of nanocrystalline ZnO powders synthesised by ultrasonic spray pyrolysis technique

    Microsoft Academic Search

    L. A. Patil; A. R. Bari; M. D. Shinde; Vinita Deo

    2011-01-01

    In this article, we report on the effect of pyrolysis temperature on structural, microstructural and optical properties of nanocrystalline ZnO powder synthesised by ultrasonic spray pyrolysis (USP) technique. Powder samples P1, P2 and P3 were prepared at various pyrolysis temperatures (temperature of 2nd zone) of 973, 1073 and 1273?K, respectively. Phases were identified and crystallite sizes were calculated from X-ray

  6. 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.

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

    SciTech Connect

    Chew, P. Y.; Lim, P. S.; Ng, M. C. [Infineon Technologies (M) Sdn Bhd, Batu Berendam, 75450 Melaka (Malaysia); Zahi, S.; You, A. H. [Faculty of Engineering and Technology, Multimedia University, Jalan Ayer Keroh Lama, 75450 Melaka (Malaysia)

    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.

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

    SciTech Connect

    Sabelström, N., E-mail: sabelstrom.n.aa@m.titech.ac.jp; Hayashi, M. [Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, Tokyo 152-8552 (Japan); Watanabe, T. [Department of Chemistry and Materials Science, Tokyo Institute of Technology, Tokyo 152-8552 (Japan); Nagata, K. [Department of Conservation Science, Tokyo University of the Arts, 12-8 Ueno Park, Taito-ku, Tokyo (Japan)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  10. Development and in vitro evaluation of ketoprofen extended release pellets using powder layering technique in a rotary centrifugal granulator.

    PubMed

    Pai, Raveendra; Pai, Aruna; Srivastava, Birendra; Kohli, Kanchan

    2011-02-01

    Powder layering technique was evaluated using laboratory scale centrifugal granulator instrument to prepare extended release pellet dosage form of ketoprofen. Ethyl cellulose and shellac polymers were used for drug layering and extended release coating in the same apparatus. Inert sugar spheres were intermittently treated with drug powder and binding solution. Combination of ethyl cellulose (45cps) and shellac was evaluated as binders at different levels (1:3 ratio, at 6%, 12%, 16% and 21%w/w polymer) for drug loading and for extended release coating (1:3 ratio at 2%, 4% and 7% w/w polymer). Pellets were evaluated for drug release study using paddle apparatus in pH 6.8 Phosphate buffer, 900ml at 100 rpm. Ethyl cellulose and shellac when used as binder during drug layering did not extend the ketoprofen release beyond 4h. However, coating of drug loaded pellets using ethyl cellulose and shellac resulted in extended release profile of ketoprofen for about 10h. Ethyl cellulose coating alone at a level of 3% w/w resulted in extended release profile. Coated pellets were evaluated for sphericity, Hardness-Friability Index and scanning electron microscopy. Scanning electron micrographs of the pellets showed a uniform coating of polymer on the core pellets substantiating the use of centrifugal granulator for extended release coating. Release pattern from the optimized batch was best explained by Higuchi's model. The drug release pattern from the pellets was found to be Non-Fickian anomalous type, involving both diffusion and erosion mechanism. Accelerated stability study of the coated pellets filled in hard gelatin capsule was conducted for 3-month period and observed for the effect on drug release profile. PMID:21118082

  11. New combustion synthesis technique for the production of (InxGa1-x)2O3 powders: Hydrazine/metal nitrate method

    E-print Network

    McKittrick, Joanna

    New combustion synthesis technique for the production of (InxGa1-x)2O3 powders: Hydrazine. The combustion reaction occurred when heating the precursors between 150 and 200 °C in a closed vessel filled by a more typical combustion synthesis reaction between nitrates and a carbonaceous fuel at a higher

  12. 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

  13. 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.

  14. Synthesis, growth and characterization of non linear optical Bisthiourea ammonium chloride single crystals by slow evaporation technique

    NASA Astrophysics Data System (ADS)

    Ilango, E.; Rajasekaran, R.; Shankar, K.; Krishnan, S.; Chithambaram, V.

    2014-11-01

    A new semi-organic nonlinear optical crystal of Bisthiourea Ammonium Chloride (BTAC) has been grown by slow evaporation technique. The crystal system and lattice parameters were determined from X-ray diffraction. Fourier Transform Infrared (FTIR) studies confirm the various functional groups present in the grown crystal. The transmittance and absorbance of electromagnetic radiation is studied through UV-Visible spectrum. The thermal behavior of the grown crystals has been investigated by TG/DTA analysis. The dielectric constant and dielectric loss has been studied as a function of frequency for various temperatures and the result were discussed in detail. The SEM analysis was also done and it revealed the surface morphology of BTAC crystal. The second harmonic generation has been confirmed by the Kurtz powder test and it is found to be 1.4 times more than that of KDP crystal.

  15. In situ preparation of titanium base composites reinforced by TiB single crystals using a powder metallurgy technique

    Microsoft Academic Search

    S Gorsse; J. P Chaminade; Y Le Petitcorps

    1998-01-01

    The feasibility of Ti\\/TiB composite by in situ precipitation of the reinforcement have been investigated. The titanium monoboride can be obtained by the chemical reaction between TiB2 and Ti powders. The fabrication method requires two stages: the first stage corresponds to the compacting of the pre-blended powders and the second one to the nucleation and growth of the TiB needles.

  16. Effect of Different Parameters on Synthesis of Moo3 Nano-Powder by Evaporation–Condensation Technique

    Microsoft Academic Search

    S. H. Hosseini; M. Saghafi; S. Heshmati-Manesh

    2012-01-01

    In the present study, MoO3 nano-powder was produced by evaporation of molybdenum oxide powder at high temperature (arround 1000°C), and its subsequent cooling in inert gas. The effect of different parameters such as pressure, temperature and type of inert gas on the morphology and particle size were examined. The samples were characterized in terms of structure, morphology, particle size and

  17. Synthesis of La0.67Ca0.33MnO3 Nanosized Powder Materials by Versatile Chemical Technique

    Microsoft Academic Search

    D. R. Sahu; B. K. Roul; P. Pramanik

    2008-01-01

    A simple low cost novel synthesis method was developed to prepare nanosized La0.67Ca0.3MnO3 (LCMO) without any requirement of a calcinations step at high temperature. Powders synthesized by a new chemical technique were fine and nano?sized with high purity perovskite structure. The size and topography of the oxides are dependent on the calcinating temperature of the precursors. The resulting particle size

  18. Characterization of TiO 2 powders and thin films prepared by non-aqueous sol–gel techniques

    Microsoft Academic Search

    Nursen Avci; Philippe F. Smet; Hilde Poelman; Nigel Van de Velde; Klaartje De Buysser; Isabel Van Driessche; Dirk Poelman

    2009-01-01

    Stable TiO2 sols were prepared using two non-aqueous sol–gel processes with titanium n-butoxide and titanium isopropoxide, respectively. Crystallization and phase transitions of powders and thin films were studied\\u000a by ex situ and in situ X-ray diffraction. For both methods, TiO2 began to crystallize around 320 °C in air. Using helium instead of air during heat treatment slowed down the crystallization\\u000a and

  19. Structural investigations of zeolites ERS-7, mordenite, and sodalite using a combination of powder diffraction and computer simulation techniques

    Microsoft Academic Search

    Branton J. Campbell

    1999-01-01

    The framework structure of dehydrated template-free ERS-7 was determined by a combination of synchrotron X-ray powder diffraction and the simulated annealing approach of Deem and Newsam. The orthorhombic unit cell ( a = 9.79976(4) A, b = 12.41163(6) A, c = 22.86063(11) A) contains 6 tetrahedral framework atoms (Si\\/Al = 8.4), all on general positions, and 14 bridging oxygens. It

  20. Structural inhomogeneity of superconducting ex situ MgB2/Cu wires made by the powder-in-tube technique

    NASA Astrophysics Data System (ADS)

    Pachla, W.; Presz, A.; Diduszko, R.; Kovác, P.; Husek, I.

    2002-09-01

    Single core MgB2 wires have been made by the powder-in-tube (PIT) method using commercial MgB2 powder (Alfa Aesar). Using the two-axial rolling process, composites have been made in a Cu sheath. Energy dispersive x-ray (EDX) mapping and scanning electron microscopy backscattered electron observations prove that there is high element segregation (phase inhomogeneity) for as-rolled and as-sintered wires, although the wire after sintering is more inhomogeneous than the as-rolled (non-sintered) wire. X-ray diffraction diffractograms confirm the presence of isotropy and the absence of texturization in the 'macroscopic' phase within the MgB2 cores, despite their thermomechanical history. The observed decrease in the value of Jc in the wire after sintering was attributed to macroscopic cracking and the worsening of the intergrain connectivity. EDX line scans have also shown high anisotropy and high inhomogeneity in the distribution of elements within the MgB2 cores. Inhomogeneity in the final product (wires) has resulted from the high macroscopic inhomogeneity observed in the starting MgB2 powder. The Cu sheath has been shown to be neutral (non-poisoning) for MgB2 cores made ex situ. However, due to its softness, it cannot properly constrain the MgB2 core or give enough support required for adequate grain connectivity.

  1. Determination of the crystal structure of anhydrous sodium dodecyl sulphate using a combination of synchrotron radiation powder diffraction and molecular modelling techniques

    Microsoft Academic Search

    L. A. Smith; R. B. Hammond; K. J. Roberts; D. Machin; G. McLeod

    2000-01-01

    The structure of anhydrous sodium dodecyl sulphate (SDS) was determined using a combination of high resolution, synchrotron, powder X-ray diffraction and molecular modelling techniques, including the use of a systematic search method to select suitable inter-molecular packing configurations for subsequent Rietveld refinement. Anhydrous SDS is monoclinic, space group P21\\/c, the unit cell dimensions are a=38.915A?,b=4.709A?,c=8.198A? and ?=93.29° and the asymmetric

  2. Porous titanium obtained by a new powder metallurgy technique: Preliminary results of human osteoblast adhesion on surface polished substrates.

    PubMed

    Biasotto, M; Ricceri, R; Scuor, N; Schmid, C; Sandrucci, M A; Di Lenarda, R; Matteazzi, P

    2003-01-01

    This study concerns a novel powder metallurgy method for producing porous titanium (pTi) exhibiting high mechanical properties. The preparation procedure consisted of the following stages: first, the preparation of Ti and titanium hydride (TiH2) powder mixtures and their consolidation with a cold isostatic press, followed by a sintering of the green bodies performed with hot isostatic press (HIP) equipment. Thermal decomposition in controlled environment of the TiH2 phase results in the foam structure. The resulting porosity percolates with a volume fraction of approximately 20%. The final material exhibits interesting mechanical properties, comparable to those of full density titanium (between grade 2 and grade 3), with the advantage of a minor density. The samples produced were tested to verify their biological response by studying the effectiveness of osteoblast adhesion and growth. In this preliminary study, osteoblastic cell morphology was investigated and compared to that observed on fully dense commercially pure titanium (Ti-cp) (ASTM, grade 3). The preliminary results were promising regarding cellular adhesion and spreading. (Journal of Applied Biomaterials & Biomechanics 2003; 1: 172-7). PMID:20803454

  3. 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.

  4. Mystery Powders

    NSDL National Science Digital Library

    American Chemical Society

    2000-01-01

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

  5. Protein Inhalation Powders: Spray Drying vs Spray Freeze Drying

    Microsoft Academic Search

    Yuh-Fun Maa; Phuong-Anh Nguyen; Theresa Sweeney; Steven J. Shire; Chung C. Hsu

    1999-01-01

    Purpose. To develop a new technique, spray freeze drying, for preparing protein aerosol powders. Also, to compare the spray freeze-dried powders with spray-dried powders in terms of physical properties and aerosol performance.

  6. Investigation on the growth and characterization of nonlinear optical single crystal 4,4'-dimethoxybenzoin by vertical Bridgman technique

    NASA Astrophysics Data System (ADS)

    Arivazhagan, T.; Rajesh, Narayana Perumal

    2014-12-01

    An organic nonlinear optical (NLO) material 4,4'-dimethoxybenzoin single crystal has been grown by vertical Bridgman technique using single wall ampoule. The grown crystal was confirmed by single crystal and powder X-ray diffraction (XRD) analyses. The functional groups of the grown crystal were identified by Fourier transform infra red analysis. The thermal behavior of the grown crystal were studied by thermo gravimetric (TG) and differential scanning calorimetric (DSC) analysis. The UV-vis-NIR spectrum has been recorded in the range 190-1100 nm and it shows that the cutoff wavelength of grown crystal is around 343 nm. The yellow emission of the grown crystal was identified by photoluminescence (PL) spectral measurements. The NLO property of the grown crystal was confirmed by Kurtz and Perry powder technique and the SHG efficiency of the grown crystal was found to be 2 times greater than KDP. The dielectric measurements were carried out and the results indicate that an increase in dielectric parameters with increase of temperature at all frequencies.

  7. 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 [Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yao, Ying, E-mail: yaoy1125@hotmail.com; Jia, Yongzhong; Xie, Shaolei; Jing, Yan [Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Yuzyuk, Yu. I. [Faculty of Physics, Southern Federal University, 5, Zorge str., Rostov-on-Don 344090 (Russian Federation)

    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?

  8. Investigations of BaxSr1-xTiO3 ceramics and powders prepared by direct current arc discharge technique

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    BaxSr1-xTiO3 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 BaxSr1-xTiO3 ceramics was found to occur at x ? 0.75. XRD investigation of as-grown BaTiO3 ceramics revealed co-existence of tetragonal and hexagonal modifications with a small amount of impurity phase BaTi4O9. No evidences of hexagonal phase were observed in Raman spectra of as-grown BaTiO3 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 BaTiO3 ceramics prepared by direct current arc discharge technique is proposed. Absence of the hexagonal phase in any BaxSr1-xTiO3 solid solution with x < 1 is discussed in the frame of specific atomic arrangement.

  9. Ultrafine powders of TiN and AlN produced by a reactive gas evaporation technique with electron beam heating

    NASA Astrophysics Data System (ADS)

    Iwama, Saburo; Hayakawa, Kenji; Arizumi, Tetsuya

    1982-01-01

    Ultrafine powders of TiN and AlN are produced by evaporating Ti and Al in a low pressure of NH 3 or N 2 gas by using electron beam heating. Powders produced are studied by means of electron microscopy and X-ray diffraction method. Both powders are confirmed to be pure nitride with cubic crystal structure for TiN and hexagonal for AlN, and to have a particle size less than 10 nm. The formation process of the nitride powder by the present method can be summarized as follows; (1) surface nitridation of the source materials, (2) vaporization of the nitride and (3) condensation into the nitride particles.

  10. Effect of NaCl on the synthesis of TiB 2 powder by a self-propagating high-temperature synthesis technique

    Microsoft Academic Search

    A. K. Khanra; L. C. Pathak; S. K. Mishra; M. M. Godkhindi

    2004-01-01

    The self-propagating high-temperature synthesis (SHS) of sub-micrometer-sized TiB2 powders were investigated by igniting the stoichiometric mixture of TiO2, H3BO3, and Mg powders and with the addition of different percentages of NaCl as SHS diluents in a resistance-heating furnace. The combustion reaction carried out in inert atmosphere (Ar) showed the SHS ignition at a temperature ?680 °C. The samples were investigated

  11. In vitro and in vivo evaluations of ketoprofen extended release pellets prepared using powder layering technique in a rotary centrifugal granulator.

    PubMed

    Pai, Raveendra; Kohli, Kanchan; Jain, Gaurav; Srivastava, Birendra

    2011-07-01

    In the present study, an extended release pellet dosage form of ketoprofen was prepared using powder layering technique. A combination of ethyl cellulose (45 cps) and shellac polymers was used as a binder (12% w/w polymer) during drug layering and an extended release coating (1:3 ratio at 2%, 4% and 7% w/w polymer) within the same apparatus. The coated pellets were characterized for sphericity, Hardness-Friability Index, and drug content, and also underwent scanning electron microscopy. In vitro dissolution was performed in 900 mL of phosphate buffer (pH 6.8) using paddle apparatus at 100 rpm. Ethyl cellulose and shellac when used as binders during drug loading did not extend ketoprofen release beyond 3 h. However, coating of the drug loaded pellets using ethyl cellulose and shellac resulted in an extended release profile of about 10 h. Using Higuchi's model and the Korsmeyer equation, the drug release mechanism from the pellets was found to be an anomalous type involving diffusion and erosion. Scanning electron microscopy was used to visualize the pellet morphology and drug release mechanism during dissolution testing. In vivo evaluations of the extended release pellets in rats indicated a significant increase in the time to reach maximum concentration (t(max)) and extent of absorption (AUC(0-?)) compared to the ketoprofen immediate release tablet blend dispersed and dosed. In conclusion, extended release pellets of ketoprofen could perform therapeutically better than conventional dosage forms, leading to improved efficacy for a prolonged period. PMID:21811920

  12. 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

  13. Preparation and characterization of Co 2+-doped Y 3Al 5O 12 nano-crystal powders by sol-gel technique

    NASA Astrophysics Data System (ADS)

    Sun, Zhihong; Yuan, Duorong; Duan, Xiulan; Wei, Xuecheng; Sun, Haiqing; Luan, Caina; Wang, Zengmei; Shi, Xuzhong; Xu, Dong; Lv, Mengkai

    2004-01-01

    Co 2+-doped Y 3Al 5O 12 (Co 2+:YAG) nanocrystalline powder sample was obtained by sol-gel method. The gel with the composition of CoO-Y 2O 3-Al 2O 3 was prepared from nitrates of yttrium, aluminum, cobalt and citric acid, and was heat-treated at temperatures ranging from 400 to 1000°C. The heated powder samples at different temperatures were characterized by X-ray diffraction analysis (XRD), transmission electron microscope (TEM), infrared spectra (IR) and emission spectra. Results showed that when the gel was heat-treated at 800°C, YAG nanocrystals with sizes 30-70 nm were formed. The emission spectrum of the heat-treated powders is identical to that of tetrahedral Co 2+ ions, which shows that Co 2+ ions are embedded in the lattice sites of YAG nanocrystals and are coordinated with four oxygens.

  14. Preparation and characterization of Co 2+-doped Y 3Al 5O 12 nano-crystal powders by sol–gel technique

    Microsoft Academic Search

    Zhihong Sun; Duorong Yuan; Xiulan Duan; Xuecheng Wei; Haiqing Sun; Caina Luan; Zengmei Wang; Xuzhong Shi; Dong Xu; Mengkai Lv

    2004-01-01

    Co2+-doped Y3Al5O12 (Co2+:YAG) nanocrystalline powder sample was obtained by sol–gel method. The gel with the composition of CoO–Y2O3–Al2O3 was prepared from nitrates of yttrium, aluminum, cobalt and citric acid, and was heat-treated at temperatures ranging from 400 to 1000°C. The heated powder samples at different temperatures were characterized by X-ray diffraction analysis (XRD), transmission electron microscope (TEM), infrared spectra (IR)

  15. Synthesis of boron nitride powders

    NASA Astrophysics Data System (ADS)

    Dreissig, Dirk Horst

    2002-09-01

    In the materials science community there is much interest in the development of new, efficient approaches for preparing ceramic powders having properties or performance characteristics not found with powders produced by traditional metallurgical synthesis methods. In this regard, aerosol-based syntheses are finding general acceptance for the preparation of non-metal and metal oxide powders. In contrast, much less effort has been given to aerosol-type syntheses for non-oxide powders despite potentially useful benefits. This dissertation describes the application of two chemical systems in aerosol assisted vapor phase synthesis (AAVS) for the preparation of spherical morphology boron oxynitride, BNxOy, powders that are subsequently converted to spherical morphology boron nitride in a second nitridation step. Chapter 1 describes the AAVS synthesis of BNxOy powders using a reaction of an aqueous boric acid containing aerosol with ammonia at 1000°C. The effect of reactor tube material, total gas flow rate, ammonia concentration, boric acid concentration, and urea addition to the boric acid aerosol on the percent oxygen composition is described. The resulting BNxOy powders contain significant amounts of oxygen that require replacement in a second stage nitridation reaction at elevated temperature under ammonia. The influences of the reaction temperature profile, crucible geometry and transformation additive on final oxygen composition and powder crystallinity are described. Chapter 2 outlines the formation of BNxOy powders from an AAVS reaction between the boron precursor (MeO)3B and ammonia. The formation of the powders is studied as a function of total gas flow rate and ammonia concentration. In all cases the resulting powders contain lower levels of oxygen compared to powders produced from aqueous boric acid aerosols. The conversion of the BNxOy powders in the second stage nitridation reaction with ammonia is examined as a function of crucible geometry, temperature profile and ammonia flow rate. In support of this process, the molecular reaction between (MeO)3B and NH3 was reexamined. The adduct, (MeO)3B·NH3, was isolated and its molecular structure determined by single crystal X-ray diffraction techniques. The results of these studies provide guidance for more detailed studies that should result in industrial scale synthesis of spherical morphology BN which currently is not formed by standard metallurgical syntheses. This new material has potential applications in several areas including the formation of BN loaded organic polymer composites.

  16. 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.

  17. Powder treatment process

    DOEpatents

    Weyand, John D. (Greensburg, PA)

    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.

  18. 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.

  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. Development of a novel pelletization technique through an extremely high-shear process using a mechanical powder processor to produce high-dose small core granules suitable for film coating.

    PubMed

    Kondo, Keita; Kato, Aya; Niwa, Toshiyuki

    2015-04-10

    We established an extremely high-shear melt pelletization technique using a mechanical powder processor to produce high-dose granules smaller than 300 ?m with properties suitable for film coating. A mixture of ethenzamide and polyethylene glycol (used as a low-melting binder) at various weight ratios was mechanically treated under various jacket temperatures. When the jacket temperature was set to 50 °C or greater, the product temperature reached the melting point of the binder, resulting in pelletization. The drug powder were pelletized with a small amount of binder to yield pellets of approximately 150 ?m with a drug content of more than 90%. The mechanism of melt pelletization through ultrahigh shearing involves a series of nucleation, consolidation, coalescence and breakage stages. The power consumption profile corresponding to each stage in the pelletization revealed that pellets between 75 and 300 ?m were effectively obtained at a large power consumption peak. The resultant pellets showed comparative sphericity and smoothness, and higher durability than commercial core granules for film coating. In conclusion, this study demonstrates that the extremely high-shear melt pelletization technique can give drug pellets with desirable properties as core particles for the coating process. PMID:25681728

  1. An improved method for shock consolidation of powders

    Microsoft Academic Search

    M. A. MEYERS; S. L. WANG

    1988-01-01

    A technique for shock consolidation of powders was developed. This technique uses the cylindrical geometry with two co-axial tubes. The powder is contained in the internal tube. The external tube is surrounded by the explosive charge, which is detonated at one end; this external tube acts as a flyer tube, impacting the internal tube. This technique generates pressures in the

  2. Mechanical etching of micro pockets by powder blasting

    Microsoft Academic Search

    D. S. Park; T. I. Seo; M. W. Cho

    2005-01-01

    The main objective of this research is to develop a mechanical etching technique to produce micro mould dies having micro pockets of hundreds of µm. A powder blasting technique is applied to stainless steel plates based on predefined process conditions. This paper describes the performance of a powder blasting technique and the effect of the number of nozzle scanning times

  3. Precision powder feeder

    DOEpatents

    Schlienger, M. Eric (Albuquerque, NM); Schmale, David T. (Albuquerque, NM); Oliver, Michael S. (Sandia Park, NM)

    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.

  4. 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.

  5. 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

  6. Microemulsion Synthesis of Nanoparticle PZT Powder

    Microsoft Academic Search

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

    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

  7. Multiple feed powder splitter

    DOEpatents

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

    2002-01-01

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

  8. 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.

  9. Which Powder is It?

    NSDL National Science Digital Library

    Sciencenter

    2014-08-27

    In this chemistry challenge, learners identify an unknown white powder by comparing it with common household powders. Learners first explore what happens when baking soda, baking powder, and washing soda are mixed with water, vinegar, and PHTH (the indicator phenolphthalein mixed with alcohol and water). Learners then work to identify the unknown based on how it reacts with the known solutions. This is a simplified form of "qualitative analysis," which was historically an important approach chemists used for identifying unknown samples.

  10. 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.

  11. 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.

  12. 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.

  13. 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 ?m, <75 ?m, and < 45 ?m; two different sizes of a hydride-dehydride [HDH] <75 ?m and < 45 ?m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  14. Compaction of Titanium Powders

    SciTech Connect

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

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

  15. Ignitability of aluminous coating powders due to electrostatic spark

    Microsoft Academic Search

    Kwangseok Choi; Nobuyasu Sakurai; Kenzo Yanagida; Haruki Itoh

    2010-01-01

    Electrostatic Powder coating which is a surface finishing technique has widely been used in paint industry since its invention in the 1960s. However, so far, insufficient attention has been paid to the powder fires and\\/or explosion hazards caused by electrostatic spark during coating process. This paper is a report of the electrostatic spark ignitability of aluminous coating powders (dry blend-type)

  16. Stratigraphic correlation with X-ray powder patterns

    E-print Network

    Singletary, John B

    1951-01-01

    . Introduction II. Theory anc Technique of Analysis by the Powder Nethod A. :. -Ray Diffraction B. The Recording Geiger Counter Spectrometer . 8 C. Construction and Usc of Soller Collimators. 15 D. Sample Preparation and Procedure for Obtaining Powder... Pattern=. II J. Interpretation of' Results. A. Pr eparation of Logs B. Discuss'on of Logs 23 25 25 33 IV. Conclusions. 36 V. Acknowledgements VI. Bibliography 37 38 STRATIGRAPHIC CORRELATION WITH X-RAY POWDER PATTERNS I. INTROIKCTION...

  17. In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method

    Microsoft Academic Search

    C. Q. Ning; Y. Zhou

    2002-01-01

    Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, ?-Ti and

  18. Structural characterization of Bi2Te3 and Sb2Te3 as a function of temperature using neutron powder diffraction and extended X-ray absorption fine structure techniques

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    The structure of Bi2Te3 (Seebeck coefficient Standard Reference Material (SRM™ 3451)) and the related phase Sb2Te3 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 Bi2Te3 and from 10 K to 298 K for Sb2Te3. The EXAFS technique for studying the local structure of the two compounds was conducted from 19 K to 298 K. Bi2Te3 and Sb2Te3 are isostructural, with a space group of R 3 ¯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 Bi2Te3 and Sb2Te3 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 Bi2Te3 are similar to those of Sb2Te3 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 Bi2Te3 and Sb2Te3. The lower Einstein temperature of Bi-Bi relative to Sb-Sb is consistent with the lower value of thermal conductivity of Bi2Te3 relative to Sb2Te3.

  19. Mystery Powder Investigation

    NSDL National Science Digital Library

    Rachel HallettNjuguna

    2012-07-27

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

  20. Talcum Powder and Cancer

    MedlinePLUS

    ... and risk of endometrial cancer in postmenopausal women. Cancer Causes Control . 2012;23:1673?1680. Gertig DM, Hunter ... Use of talcum powder and endometrial cancer risk. Cancer Causes Control . 2012;2:513?519. Rosenblatt KA, Weiss ...

  1. 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.

  2. 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...

  3. Hepagene (PowderJect).

    PubMed

    Jones, Taff

    2002-07-01

    Celltech Group (formerly Medeva) developed Hepagene, a recombinant polyvalent vaccine with potential activity against hepatitis B virus infections [353474]. In September 2000, PowderJect acquired the product as part of its acquisition of Celltech's vaccine manufacturing business [381557]. In July 2001, PowderJect reported that evaluation was nearing completion. At this time, the company expected to launch the vaccine in the coming months [443490]. Hepagene is a polyvalent vaccine with S, pre-S1 and pre-S2 hepatitis B epitopes forming the basis of its antigenicity. Additionally, these surface markers have been glycosylated in order to resemble the live virus more closely [254780]. By June 2000, Celltech and PowderJect were evaluating Hepagene, utilizing PowderJect's needle-less injection technology [379536]. In December 1999, Lehman Brothers predicted that the product had a 50% chance of reaching the treatment (rather than prevention) market, with potential peak sales of US $600 million [352078]. PMID:12186276

  4. Mathematical modeling of powder paint particle trajectories in electrostatic painting

    Microsoft Academic Search

    F. Sharmene Ali; Terence E. Base; Ion I. Inculet

    2000-01-01

    The trajectories of charged powder particles in an electrostatic powder coating system were modeled considering electrical and fluid forces. The mathematical model employed an iterative technique wherein the charge simulation method was used to compute the electric field strength and the method of characteristics was used to compute the charge density in the gun-to-target region. The fluid flow between the

  5. Consolidation of amorphous oxide powders using spark plasma sintering

    Microsoft Academic Search

    Daniela Marisa Fredrick

    2009-01-01

    The objective of this study is to synthesize amorphous oxide powders and sinter the systems close to or at theoretical density for optical transparency while retaining the amorphous structure using the Spark Plasma Sintering (SPS) method. In addition, the parameters that govern the formation of these systems were investigated. The main powder processing techniques are sol-gel, flame-spaying and spherodizing. The

  6. Dispersion of carbon nanotubes (CNTs) in aluminum powder

    Microsoft Academic Search

    A. Esawi; K. Morsi

    2007-01-01

    In the present work, we use mechanical alloying (MA) for the first time to generate a homogenous distribution of 2wt% CNT within Al powders. The effect of milling time (up to 48h) on the morphological development of the powders and dispersion of CNTs was investigated. The results show that the technique is effective in dispersing the nanotubes within the soft

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. X-RAY POWDER DIFFRACTION 2 (XPD-2) SCIENTIFIC SCOPE

    E-print Network

    Ohta, Shigemi

    APPLICATIONS TECHNIQUES: · Atomic Pair Distribution Function · Small-Angle X-ray Scattering (SAXS) (Qmin= 0 systems, multiferroics, thermoelectrics, catalysts, nanomaterials, etc. The X-ray Powder Diffraction 2

  16. Macromolecular powder diffraction : structure solution via molecular.

    SciTech Connect

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

    2009-01-01

    Macromolecular powder diffraction is a burgeoning technique for protein structure solution - ideally suited for cases where no suitable single crystals are available. Over the past seven years, pioneering work by Von Dreele et al. [1,2] and Margiolaki et al. [3,4] has demonstrated the viability of this approach for several protein structures. Among these initial powder studies, molecular replacement solutions of insulin and turkey lysozyme into alternate space groups were accomplished. Pressing the technique further, Margiolaki et al. [5] executed the first molecular replacement of an unknown protein structure: the SH3 domain of ponsin, using data from a multianalyzer diffractometer. To demonstrate that cross-species molecular replacement using image plate data is also possible, we present the solution of hen egg white lysozyme using the 60% identical human lysozyme (PDB code: 1LZ1) as the search model. Due to the high incidence of overlaps in powder patterns, especially in more complex structures, we have used extracted intensities from five data sets taken at different salt concentrations in a multi-pattern Pawley refinement. The use of image plates severely increases the overlap problem due to lower detector resolution, but radiation damage effects are minimized with shorter exposure times and the fact that the entire pattern is obtained in a single exposure. This image plate solution establishes the robustness of powder molecular replacement resulting from different data collection techniques.

  17. 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. [Naval Surface Warfare Center, Carderock Division, West Bethesda, Maryland 20817 (United States); Wong-Ng, W. [Materials Measurement Science Division National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Huang, Q. [Center for Neutron Research National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Tang, W. [Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018 (China); Thompson, A.; Sharp, J. [Marlow Industries, Inc Dallas, Texas 75238 (United States)

    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}.

  18. Iowa Powder Atomization Technologies

    SciTech Connect

    None

    2012-01-01

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

  19. Powder towpreg process development

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.; Marchello, Joseph M.

    1991-01-01

    The process for dry powder impregnation of carbon fiber tows being developed at LaRC overcomes many of the difficulties associated with melt, solution, and slurry prepregging. In the process, fluidized powder is deposited on spread tow bundles and fused to the fibers by radiant heating. Impregnated tows have been produced for preform, weaving, and composite materials applications. Design and operating data correlations were developed for scale up of the process to commercial operation. Bench scale single tow experiments at tow speeds up to 50 cm/sec have demonstrated that the process can be controlled to produce weavable towpreg. Samples were woven and molded into preform material of good quality.

  20. 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

  1. Study of the fast reaction characteristics of aluminized PETN explosive powders

    Microsoft Academic Search

    Hu Dong; Sun Zhumei

    1996-01-01

    The fast reaction characteristics of aluminized PETN explosive powders have been studied successfully by means of a spectrum-detecting and recovery technique. The results show that the appropriate particle size and content of aluminium powder in the aluminized PETN explosive powders are 44 ?m and 33%, respectively.

  2. Study of the fast reaction characteristics of aluminized PETN explosive powders

    SciTech Connect

    Hu Dong; Sun Zhumei [Chengdu Univ. of Science and Technology (China). Inst. of Applied Physics] [Chengdu Univ. of Science and Technology (China). Inst. of Applied Physics; [Southwest Inst. of Fluid Physics, Chengdu (China). China National Laboratory for Shock Wave and Detonation Physics Research

    1996-05-01

    The fast reaction characteristics of aluminized PETN (pentaerythrite tetranitrate) explosive powders have been studied successfully by means of a spectrum-detecting and recovery technique. The results show that the appropriate particle size and content of aluminium powder in the aluminized PETN explosive powders are 44 {micro}m and 33%, respectively.

  3. Magnetothermal characteristics of amorphous Fe-Si-B powder produced by spark erosion

    Microsoft Academic Search

    T. Yamaguchi; K. Narita

    1977-01-01

    It has been found that the amorphous powder of a transition metal - metalloid alloy can be prepared by the spark erosion technique. The powder consists of roughly spherical particles whose diameters are ranging from 0.5 ?m to 30?m. The preparation procedure of the powder is described and its magnetothermal characteristics and the crystallization behaviours are discussed.

  4. 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.

  5. Powder Cores s Molypermalloy

    E-print Network

    Software q Current Transformer Design Software q Inductor Design Software q Mag Amp Design Software POWDER.mag-inc.com PRODUCT LITERATURE AND DESIGN SOFTWARE CD CONTAINS q All Product Literature q Common Mode FIlter Design the Proper Core for Saturating Transformers q TWC-S3 Inverter Transformer Core Design and Material Selection

  6. 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)

  7. Properties of lead-free conductive thick films of co-precipitated silver–palladium powders

    Microsoft Academic Search

    V. Deshpande; A. Kshirsagar; S. Rane; T. Seth; G. J. Phatak; U. P. Mulik; D. P. Amalnerkar

    2005-01-01

    Silver–palladium alloy films were made by thick film technique using three types of powders prepared by co-precipitation route. The powders were prepared by varying the palladium weight contents (5, 10 and 15% Pd and denoted as Pd5, Pd10 and Pd15, respectively). The powders were analyzed by XRD, SEM\\/EDAX and TG\\/DTA. The average particle size of the prepared powders ranged from

  8. 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

    Titanium and its associated alloys have been used in industry for over 50 years and have become more popular in the recent decades. Titanium has been most successful in areas where the high strength to weight ratio provides an advantage over aluminum and steels. Other advantages of titanium include biocompatibility and corrosion resistance. Electron Beam Melting (EBM) is an additive manufacturing (AM) technology that has been successfully applied in the manufacturing of titanium components for the aerospace and medical industry with equivalent or better mechanical properties as parts fabricated via more traditional casting and machining methods. As the demand for titanium powder continues to increase, the price also increases. Titanium spheroidized powder from different vendors has a price range from 260/kg-450/kg, other spheroidized alloys such as Niobium can cost as high as $1,200/kg. Alternative titanium powders produced from methods such as the Titanium Hydride-Dehydride (HDH) process and the Armstrong Commercially Pure Titanium (CPTi) process can be fabricated at a fraction of the cost of powders fabricated via gas atomization. The alternative powders can be spheroidized and blended. Current sectors in additive manufacturing such as the medical industry are concerned that there will not be enough spherical powder for production and are seeking other powder options. It is believed the EBM technology can use a blend of spherical and angular powder to build fully dense parts with equal mechanical properties to those produced using traditional powders. Some of the challenges with angular and irregular powders are overcoming the poor flow characteristics and the attainment of the same or better packing densities as spherical powders. The goal of this research is to demonstrate the feasibility of utilizing alternative and lower cost powders in the EBM process. As a result, reducing the cost of the raw material to reduce the overall cost of the product produced with 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.

  9. 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.

  10. Screening mail for powders using terahertz technology

    NASA Astrophysics Data System (ADS)

    Kemp, Mike

    2011-11-01

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

  11. Some characteristics of powder silica counters

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Pinsky, L. S.

    1980-01-01

    Following the original idea of Peters, techniques have been developed to fabricate large area powder silica counters with refractive index between 1.06 to 1.12 in thicknesses of 1 cm and 2 cm respectively. The maximum size counter is 25 cm x 25 cm but the technique can be easily extended to 40 cm x 30 cm counters. Techniques have also been developed to dope this counter with the wavelength shifter p-terphenyl uniformly. The results of test runs at the Brookhaven National Laboratory and of laboratory runs using a superconducting magnet spectrometer on their performance are reported.

  12. Powder characteristics and coating conditions of fresh and reused polyester resins for electrostatic powder coating: powder recycling and loss prevention

    Microsoft Academic Search

    A. W. Lothongkum; R. Nonthapone; K. Seangkiatiyuth; W. Tanthapanichkoon

    2007-01-01

    Powder characteristics and coating conditions are significant factors in electrostatic powder coating. In this work, powder characteristics of the reused polyester resin or recycled powder particles in terms of shape, size, particle size distribution, moisture content, density, flowability, fluidity and chargeability were compared with those of fresh resin or as-received powder to consider powder recycling. The coating conditions for a

  13. 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.

  14. Fluidised powder as a new target technology

    E-print Network

    McDonald, Kirk

    : scope for a rig #12;Powder jet test plant layout Compressed air supplyVacuum/air powder #12;Powder jet/w solid to air ratio is not good enough!) · How does a dense, dense powder jet behave like? Preliminary tests at Gericke ltd #12;AIR/PRESSURE IN POWDER IN JET GENERATION AIR EXTRACTION POWDER OUT DENSE

  15. Surface dose measurement using TLD powder extrapolation

    SciTech Connect

    Rapley, P. [Regional Cancer Care, Thunder Bay Regional Health Sciences Centre, Thunder Bay, Ontario (Canada)]. E-mail: rapleyp@tbh.net

    2006-10-01

    Surface/near-surface dose measurements in therapeutic x-ray beams are important in determining the dose to the dermal and epidermal skin layers during radiation treatment. Accurate determination of the surface dose is a difficult but important task for proper treatment of patients. A new method of measuring surface dose in phantom through extrapolation of readings from various thicknesses of thermoluminescent dosimeter (TLD) powder has been developed and investigated. A device was designed, built, and tested that provides TLD powder thickness variation to a minimum thickness of 0.125 mm. Variations of the technique have been evaluated to optimize precision with consideration of procedural ease. Results of this study indicate that dose measurements (relative to D{sub max}) in regions of steep dose gradient in the beam axis direction are possible with a precision (2 standard deviations [SDs]) as good as {+-} 1.2% using the technique. The dosimeter was developed and evaluated using variation to the experimental method. A clinically practical procedure was determined, resulting in measured surface dose of 20.4 {+-} 2% of the D{sub max} dose for a 10 x 10 cm{sup 2}, 80-cm source-to-surface distance (SSD), Theratron 780 Cobalt-60 ({sup 60}C) beam. Results obtained with TLD powder extrapolation compare favorably to other methods presented in the literature. The TLD powder extrapolation tool has been used clinically at the Northwestern Ontario Regional Cancer Centre (NWORCC) to measure surface dose effects under a number of conditions. Results from these measurements are reported. The method appears to be a simple and economical tool for surface dose measurement, particularly for facilities with TLD powder measurement capabilities.

  16. An insight into powder entrainment and drug delivery mechanisms from a modified Rotahaler®.

    PubMed

    Sim, Sally; Margo, Kenneth; Parks, Jonathan; Howell, Ruth; Hebbink, Gerald A; Orlando, Laurence; Larson, Ian; Leslie, Philip; Ho, Louise; Morton, David A V

    2014-12-30

    This study aims to improve understanding of the powder fluidisation and aerosolisation processes unique to a split capsule dry powder inhaler. It uses a combination of dynamic real-time methods and a suite of powder material physicochemical characterisation methods. The study focused on examining the effect of different characteristics of lactose carrier employed, and considered specifically the powder fluidisation, entrainment and de-agglomeration mechanisms. A GSK Rotahaler(®) was selected as the inhaler device. Powder fluidisation and entrainment were investigated using the ensemble technique of laser diffraction and high-speed imaging. This ensemble technique afforded both the powder entrainment profile and simultaneous visual confirmation of the capsule movement and powder fluidisation within the Rotahaler. The results showed that powder fluidisation from a dynamic split capsule was substantially different to that from a static powder bed. Furthermore, the presence of the split capsule dominated powder emission mechanisms from the Rotahaler, regulated by its impaction on the grid/Rotahaler wall and the rotational movement in the entrained air. Of all the material characterisation metrics, the most significant linear correlation was revealed between powder permeability and the aerosolisation efficiency as measured by fine particle fraction (R(2)=0.98). This indicates that drug delivery from the Rotahaler was mainly governed by the influence of the cohesive fine particle size component. Powder permeability as a practical test may afford an effective and practical predictive link between the raw excipients and drug delivery performance from the capsule device. PMID:25196720

  17. Plasma technology for the production of metallic and ceramic powder

    SciTech Connect

    Vursel, P.B. [Plasmasil Co. Ltd., Moscow (Russian Federation)

    1995-12-31

    Plasma technology gives an opportunity to obtain powders of different materials in a widest range of sizes with desirable properties. Some techniques of production and some properties of ultrafine, refractory, semiconducting, magnetic powders are described. An influence of plasma parameters (temperature, flow rate, composition, rate of heating) and quenching conditions (quenching agent temperature and composition, cooling rate) on chemical and phase compositions, microstructure, particle`s size and shape is established by experiments. The last parameters determine exploitation properties of powders and items made of them.

  18. 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.

  19. Sintering of powder mixtures and the growth of ferrous powder metallurgy

    Microsoft Academic Search

    K. S Narasimhan

    2001-01-01

    Advances in the understanding of sintering of powder mixtures contributed significantly to the growth of ferrous powder metallurgy industry. Solid-state sintering and liquid-phase activated sintering play an important role in the sintering of powder mixtures. In this paper, sintering of iron powder with graphite; iron powder with copper and graphite; iron powder with nickel and graphite; iron powder with phosphorus;

  20. Structural evolution in mechanically alloyed Al-Fe powders

    Microsoft Academic Search

    D. K. Mukhopadhyay; C. Suryanarayana

    1995-01-01

    The structural evolution in mechanically alloyed binary aluminum-iron powder mixtures containing 1, 4, 7.3, 10.7, and 25 at. pct Fe was investigated using X-ray diffraction (XRD) and electron microscopic techniques. The constitution (number and identity of phases present), microstructure (crystal size, particle size), and transformation behavior of the powders on annealing were studied. The solid solubility of Fe in Al

  1. Structural evolution in mechanically alloyed Al-Fe powders

    Microsoft Academic Search

    D. K. Mukhopadhyay; C. Suryanarayana

    1995-01-01

    The structural evolution in mechanically alloyed binary aluminum-iron powder mixtures containing 1, 4, 7.3, 10.7, and 25 at.\\u000a pct Fe was investigated using X-ray diffraction (XRD) and electron microscopic techniques. The constitution (number and identity\\u000a of phases present), microstructure (crystal size, particle size), and transformation behavior of the powders on annealing\\u000a were studied. The solid solubility of Fe in Al

  2. Ultrafine ceria powders via glycine-nitrate combustion

    Microsoft Academic Search

    R. D Purohit; B. P Sharma; K. T Pillai; A. K Tyagi

    2001-01-01

    The ultrafine ceria powders have been synthesized by the combustion technique using glycine as a fuel and nitrate as an oxidizer. The auto-ignition (at ?200°C) of the viscous liquids containing cerium nitrate and glycine resulted in voluminous ceria powders. An interpretation based on an adiabatic flame temperature, for different fuel-to-oxidant ratios, has been proposed for the nature of combustion and

  3. Infrared thermography of burn front propagation in heat powders

    SciTech Connect

    Kelly, M.D.; Abney, L.D.

    1984-01-01

    Heat powders are consolidated into dense composites to form concentrated chemical heat sources. During the reaction, a high temperature burn front propagates through the composites. The burn front is preceded by a lower temperature thermal front which generates thermal gradients. Thermography was used to determine thermal gradients preceding the burn front, during the reaction of the consolidated heat powder. The techniques involved along with the resulting thermography will be discussed.

  4. Infrared Thermography Of Burn Front Propagation In Heat Powders

    NASA Astrophysics Data System (ADS)

    Kelly, M. D.; Abney, L. D.

    1985-03-01

    Heat powders are consolidated into dense composites to form concentrated chemical heat sources. During the reaction, a high temperature burn front propagates through the composites. The burn front is preceded by a lower temperature thermal front which generates thermal gradients. Thermography was used to determine thermal gradients preceding the burn front, during the reaction of the consolidated heat powder. The techniques involved along with the resulting thermography will be discussed.

  5. Surface oxide debonding in field assisted powder sintering

    Microsoft Academic Search

    K. R Anderson; J. R Groza; M Fendorf; C. J Echer

    1999-01-01

    Field activated sintering techniques (FAST) have been applied to two high-temperature powder materials: tungsten and NiAl. High and atomic resolution electron microscopy (HREM\\/ARM) of tungsten powder sintered via FAST showed essentially clean boundaries. Analytical transmission electron microscopy (TEM) of FAST sintered NiAl also showed boundaries free of surface oxide layer(s). However, small alumina precipitates were found at and near prior

  6. Metallurgical examination of powder metallurgy uranium alloy welds

    Microsoft Academic Search

    G. M. Alexander-Morrison; A. G. Dobbins; R. K. Holbert; M. W. Doughty

    1986-01-01

    Inertia welding provided a successful technique for joining full density, powder metallurgy uranium-6 wt pct niobium alloy.\\u000a Initial joining attempts concentrated on the electron beam method, but this method failed to produce a sound weld. The electron\\u000a beam welds and the inertia welds were evaluated by radiography and metallography. Electron beam welds were attempted on powder\\u000a metallurgy plates which contained

  7. Capabilities and limitations of using powder rheology and permeability to predict dry powder inhaler performance.

    PubMed

    Cordts, Eike; Steckel, Hartwig

    2012-10-01

    Dry powder inhalers play a major role in today's treatment of various respiratory diseases. A lot of effort has been put into the optimization of a device and the appropriate formulation regarding its local lung deposition. However, the complexity and interactions of different factors governing powder dispersion and, therefore, its inhalable fraction challenge research groups around the world. In the current work, binary lactose blends and adhesive ternary powder mixtures containing additional budesonide fines were produced and analyzed with dispersion measurements on the one hand and permeability and aeration measurements conducted with a powder rheometer on the other hand. By comparing the results of the bulk property and dispersion tests, it was expected to gain a better understanding about the effect of excipient fines addition to an adhesive powder mixture. It could be observed that with permeability testing it was possible to clearly differentiate between different amounts of fines within mixtures. However, no correlation between permeability or aeration test values and drug fine particle fraction could be determined for the observed range. Nevertheless, the use of different characterization techniques led to a clearer understanding about the influence of fines addition to an adhesive mixture. It could be demonstrated that after the surface of carrier crystals had been fully saturated, drug particles got incorporated in more stable fines' agglomerates, which resulted in a decrease in fine particle fraction upon dispersion. PMID:22902789

  8. 1987 Annual Powder Metallurgy Conference, Dallas, TX, May 17-20, 1987, Proceedings

    Microsoft Academic Search

    C. L. Freeby; H. Hjort

    1987-01-01

    The papers presented in this volume provide an overview of the current status of the P\\/M technology. Topics discussed include low-temperature compaction of titanium alloys by rapid omnidirectional compaction (ROC); gravitational contributions to microstructural coarsening in liquid phase sintering; applications of powder metallurgy techniques to produce improved bearing elements for cryogenic aerospace engine turbopumps; and powder metallurgy techniques in the

  9. Comminution of stainless steel powders

    Microsoft Academic Search

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

    1974-01-01

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

  10. Dry powder aerosol delivery systems: current and future research directions.

    PubMed

    Chan, Hak-Kim

    2006-01-01

    Development of dry powder aerosol delivery system involves powder production, formulation, dispersion, delivery, and deposition of the powder aerosol in the airways. Insufficiency of conventional powder production by crystallization and milling has led to development of alternative techniques. Over the last decade, performance of powder formulations has been improved significantly through the use of engineered drug particles and excipient systems which are (i) of low aerodynamic diameters (being porous or of low particle density), and/or (ii) less cohesive and adhesive (via corrugated surfaces, low bulk density, reduced surface energy and particle interaction, hydrophobic additives, and fine carrier particles). Early insights into particle forces and surface energy that help explain the improvement have been provided by analytical techniques such as the atomic force microscopy (AFM) and inverse gas chromatography (IGC). Relative humidity is critical to the performance of dry powder inhaler (DPI) products via capillary force and electrostatic interaction. Electrostatic charge of different particle size fractions of an aerosol can now be measured using a modified electrical low-pressure impactor (ELPI). Compared with powders, much less work has been done on the inhaler devices at the fundamental level. Most recently, computational fluid dynamics has been applied to understand how the inhaler design (such as mouthpiece, grid structure, air inlet) affects powder dispersion. The USP throat is known to under-represent the oropharyngeal deposition of DPI aerosols. Studies using magnetic resonance imaging (MRI) model casts have been undertaken to explain the inter- and intra- subject variation in oropharyngeal deposition. Most of the lung deposition studies performed on commercial products did not allow a thorough understanding of the determinants affecting in vivo lung deposition. A more systematic approach would be necessary to build a useful database on the dependence of lung deposition on the breathing parameters, inhaler design, and powder formulation properties. PMID:16551211

  11. Structural materials by powder HIP for fusion reactors

    NASA Astrophysics Data System (ADS)

    Dellis, C.; Le Marois, G.; van Osch, E. V.

    1998-10-01

    Tokamak blankets have complex shapes and geometries with double curvature and embedded cooling channels. Usual manufacturing techniques such as forging, bending and welding generate very complex fabrication routes. Hot Isostatic Pressing (HIP) is a versatile and flexible fabrication technique that has a broad range of commercial applications. Powder HIP appears to be one of the most suitable techniques for the manufacturing of such complex shape components as fusion reactor modules. During the HIP cycle, consolidation of the powder is made and porosity in the material disappears. This involves a variation of 30% in volume of the component. These deformations are not isotropic due to temperature gradients in the part and the stiffness of the canister. This paper discusses the following points: (i) Availability of manufacturing process by powder HIP of 316LN stainless steel (ITER modules) and F82H martensitic steel (ITER Test Module and DEMO blanket) with properties equivalent to the forged one.(ii) Availability of powerful modelling techniques to simulate the densification of powder during the HIP cycle, and to control the deformation of components during consolidation by improving the canister design.(iii) Material data base needed for simulation of the HIP process, and the optimisation of canister geometry.(iv) Irradiation behaviour on powder HIP materials from preliminary results.

  12. Mound powder loader, Mod 1

    SciTech Connect

    Gress, A.V. Jr.

    1985-08-21

    At the investigation of Sandia Albuquerque, a semiautomatic powder loader was designed and fabricated for pyrotechnics devices. The basic functions of the system were to load a precise, measured amount of powder into a charge holder and to compact the mixture to a specified density. This report documents the history, rationale, design, and performance of the Mod 1 loader.

  13. Generation of a high-velocity jet in the electrothermal explosion of conductive ceramic powders

    NASA Astrophysics Data System (ADS)

    Tamura, H.; Konoue, M.; Ikeda, Y.; Soda, T.; Sawaoka, A. B.

    1998-03-01

    The electrothermal explosion spraying of conductive ceramic powders was characterized according to the electric and gas dynamic behavior of heated powders. Optical observation revealed the generation of the jetting with a leading velocity over 3 km/s. The velocity depended on the shape of the jet and the energy supplied to the powder. The heating process was related to the jetting process of the heated powders. The total electric energy supplied to the powder was two to three times the theoretical amount needed to melt the powder. Such electric energy was used for heating and accelerating the powder. This spray technique is characterized with the high-velocity jet consisting of high-pressure gas and molten ceramic particles.

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

    SciTech Connect

    Brown, Geoffrey W [Los Alamos National Laboratory; Sandstrom, Mary M [Los Alamos National Laboratory; Giambra, Anna M [Los Alamos National Laboratory; Archuleta, Jose G [Los Alamos National Laboratory; Monroe, Deirde C [Los Alamos National Laboratory

    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.

  15. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Copper powder. 73.2647 Section 73...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

  16. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Copper powder. 73.2647 Section 73...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

  17. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  18. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Copper powder. 73.2647 Section 73...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

  19. 21 CFR 73.2647 - Copper powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Copper powder. 73.2647 Section 73...CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity...

  20. Thermal behavior of aluminum powder and potassium perchlorate mixtures by DTA and TG

    Microsoft Academic Search

    S. M. Pourmortazavi; M. Fathollahi; S. S. Hajimirsadeghi; S. G. Hosseini

    2006-01-01

    In this work the thermal decomposition characteristics of micron sized aluminum powder+potassium perchlorate pyrotechnic systems were studied with thermal analytical techniques. The results show that the reactivity of aluminum powder in air increases as the particle size decreases. Pure aluminum with 5?m particle size has a fusion temperature about 647°C, but this temperature for 18?m powder is 660°C. Pure potassium

  1. Heating ferrite powder with AC magnetic field for thermal coagulation therapy

    Microsoft Academic Search

    K. Konishi; T. Maehara; T. Kamimori; H. Aono; T. Naohara; H. Kikkawa; Y. Watanabe; K. Kawachi

    2004-01-01

    In order to realize a thermal coagulation technique in which tumors are locally heated up to 60–80°C by inductive heating and necrotized, selection of ferrite powder and frequency are performed. We investigate the heating properties by applying AC magnetic field for various ferrite powders (micrometer size of the particles). The temperature rise for Mg-ferrite (MgFe2O4) powder is the largest around

  2. Nanostructured interpenetrating phase composites by non-equilibrium compaction of in situ synthesized powders

    Microsoft Academic Search

    O. I. Lomovsky; D. V. Dudina; M. A. Korchagin; V. I. Mali; Y.-S. Kwon; J.-S. Kim

    2005-01-01

    We suggest using two-stage processing of metal-ceramic interpenetrating phase composites (IPCs) including preparation of composite powder precursors by reaction in a metal matrix and subsequent compaction of as-synthesized nanostructured powders. The appropriate choice of compaction technique allows obtaining dense nanostructured bulk IPCs. Bulk nanostructured TiB2-Cu IPCs were fabricated by spark plasma sintering (SPS) and shock wave compaction of powder precursors.

  3. 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.

  4. 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.

  5. Laser production of articles from powders

    DOEpatents

    Lewis, Gary K. (Los Alamos, NM); Milewski, John O. (Santa Fe, NM); Cremers, David A. (Los Alamos, NM); Nemec, Ronald B. (White Rock, NM); Barbe, Michael R. (White Rock, NM)

    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.

  6. 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.

  7. 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.

  8. Boron Diffusion In Silicon From Ultrafine Boron-Silicon Powder

    NASA Astrophysics Data System (ADS)

    Gupta, Arunava; West, Gary A.; Donlan, Jeffrey P.

    1984-06-01

    A CO2 laser pyrolysis technique has been used to prepare ultrafine (< 0.1p diameter) boron-silicon powders with different boron concentrations. These powders have been used as a spin-on boron diffusion source for silicon wafers. The spin-on colloidal suspension is prepared by mixing the powder with a thermally degradable polymer binder, polymethyl-methacrylate (PMMA), and an organic vehicle, cyclohexanone. Thin, uniform films are spun-on using a standard photoresist spinner. Two different procedures are followed in diffusing the boron from the boron-silicon powder. In the first process, the boron is diffused by heating the wafer in an argon ambient (1000-1260°C). The excess dopant layer is removed by oxidation (02) and subsequent etching (HF). In the second process, the powder is first converted to a borosilicate glass layer by oxidation, followed by diffusion in an argon ambient. Some experiments using commercially available boron nitride powder as a diffusion source are also discussed.

  9. 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

  10. 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.

  11. Powder collection apparatus/method

    DOEpatents

    Anderson, Iver E. (Ames, IA); Terpstra, Robert L. (Ames, IA); Moore, Jeffery A. (Ames, IA)

    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.

  12. 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.

  13. Structural evolution in mechanically alloyed Al-Fe powders

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, D. K.; Suryanarayana, C.; Froes, F. H. (Sam)

    1995-08-01

    The structural evolution in mechanically alloyed binary aluminum-iron powder mixtures containing 1, 4, 7.3, 10.7, and 25 at. pct Fe was investigated using X-ray diffraction (XRD) and electron microscopic techniques. The constitution (number and identity of phases present), microstructure (crystal size, particle size), and transformation behavior of the powders on annealing were studied. The solid solubility of Fe in Al has been extended up to at least 4.5 at. pct, which is close to that observed using rapid solidification (RS) (4.4 at. pct), compared with the equilibrium value of 0.025 at. pct Fe at room temperature. Nanometer-sized grains were observed in as-milled crystalline powders in all compositions. Increasing the ball-to-powder weight ratio (BPR) resulted in a faster rate of decrease of crystal size. A fully amorphous phase was obtained in the Al-25 at. pct Fe composition, and a mixed amorphous phase plus solid solution of Fe in Al was developed in the Al-10.7 at. pct Fe alloy, agreeing well with the predictions made using the semiempirical Miedema model. Heat treatment of the mechanically alloyed powders containing the supersaturated solid solution or the amorphous phase resulted in the formation of the Al3Fe intermetallic in all but the Al-25 at. pct Fe powders. In the Al-25 at. pct Fe powder, formation of nanocrystalline Al5Fe2 was observed directly by milling. Electron microscope studies of the shock-consolidated mechanically alloyed Al-10.7 and 25 at. pct Fe powders indicated that nanometer-sized grains were retained after compaction.

  14. Recycling of heavy metal alloy turnings to powder by oxidation–reduction process

    Microsoft Academic Search

    He Yuehui; Chen Libao; Huang Baiyun; P. K. Liaw

    2003-01-01

    The processes of direct recycling heavy metal turnings by oxidation–reduction technique have been investigated in details. The average particle size of recycled alloy powders was about 1.5 ?m, and the shape of powder particle was regular when the final reduction temperature was 850 °C. The average size of the particle increased to 5 and 8 ?m when increasing the reduction

  15. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  16. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  17. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  18. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  19. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  20. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  1. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  2. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  3. 30 CFR 57.6901 - Black powder.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  4. 30 CFR 56.6901 - Black powder.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  5. 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.

  6. Ceramic oxide powders and the formation thereof

    DOEpatents

    Katz, Joseph L. (Baltimore, MD); Hung, Cheng-Hung (Baltimore, MD)

    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.

  7. Density gradient fractionation of dentine and bone powder

    Microsoft Academic Search

    Bengt Engfeldt; Anders Hjerpe

    1974-01-01

    In order to obtain enough material to analyse the organic matrix of mineralizing tissue a technique for preparative separation according to the degree of mineralization was developed. The method employs ultracentrifugation of powdered material in density gradients made from acetone and bromoform. The density range of the fractions is checked by refractive index measurements of the gradient medium. The amount

  8. Adsorption of basic dyes from aqueous solution onto pumice powder

    Microsoft Academic Search

    Feryal Akbal

    2005-01-01

    The adsorption of methylene blue and crystal violet on pumice powder samples of varying compositions was investigated using a batch adsorption technique. The effects of various experimental parameters, such as adsorbent dosage, initial dye concentration, and contact time, were also investigated. The extent of dye removal increased with decreased initial concentration of the dye and also increased with increased contact

  9. NanoComposite Stainless Steel Powder Technologies

    SciTech Connect

    DeHoff, R.; Glasgow, C. (MesoCoat, Inc.)

    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.

  10. 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.

  11. Magnetic properties and loss separation in iron powder soft magnetic composite materials

    NASA Astrophysics Data System (ADS)

    De Wulf, Marc; Anestiev, Ljubomir; Dupré, Luc; Froyen, Ludo; Melkebeek, Jan

    2002-05-01

    New developments in powder metallurgical composites make soft magnetic composite (SMC) material interesting for application in electrical machines, when combined with new machine design rules and new production techniques. In order to establish these design rules, one must pay attention to electromagnetic loss characteristics of SMC material. In this work, five different series of iron based SMCs are produced and studied: (1) Pure iron powder with resin; (2) sintered iron based powders; (3) pure iron powder with additions of Zn-st and carbon; (4) iron based powder alloys (Fe,Nb,Si); (5) commercially available iron powder "Somaloy." The specimens were shaped as rectangular rods and characterized on a miniature single sheet tester which was calibrated to Epstein. The measured energy losses are analyzed following the loss separation theory of Bertotti, in which the total energy loss is decomposed into hysteresis loss, classical Foucault loss, and an excess loss component.

  12. A phase-matchable nonlinear optical material N-(3-nitrophenyl)phthalimide: Synthesis, crystal growth and characterization

    Microsoft Academic Search

    H. J. Ravindra; M. R. Suresh Kumar; Chitharanjan Rai; S. M. Dharmaprakash

    2006-01-01

    The N-(3-nitrophenyl)phthalimide (N3NP) single crystal of size 4mm×1mm×0.5mm, sufficient enough to confirm the existence of phase-matching direction in the crystal using the Kurtz and Perry powder second-harmonic generation (SHG) measurements, was grown by slow evaporation solution growth technique using DMF solvent. Powder XRD, FTIR, CHN analysis and H1NMR technique were employed to characterize N3NP single crystal. The single crystal XRD

  13. A phase-matchable nonlinear optical material N-(3-nitrophenyl)phthalimide: Synthesis, crystal growth and characterization

    Microsoft Academic Search

    H. J. Ravindra; M. R. Suresh Kumar; Chitharanjan Rai; S. M. Dharmaprakash

    2006-01-01

    The N-(3-nitrophenyl)phthalimide (N3NP) single crystal of size 4 mm×1 mm×0.5 mm, sufficient enough to confirm the existence of phase-matching direction in the crystal using the Kurtz and Perry powder second-harmonic generation (SHG) measurements, was grown by slow evaporation solution growth technique using DMF solvent. Powder XRD, FTIR, CHN analysis and H1NMR technique were employed to characterize N3NP single crystal. The

  14. Development of an Experimental Facility for Flame Speed Measurements in Powdered Aerosols 

    E-print Network

    Vissotski, Andrew John

    2012-10-19

    Research with heterogeneous mixtures involving solid particulate in closed, constant-volume bombs is typically limited by the powder dispersion technique. This work details the development of an experimental apparatus that ...

  15. 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

  16. Industrial aspects of synchrotron X-ray powder diffraction

    NASA Astrophysics Data System (ADS)

    Cernik, R. J.; Barnes, P.

    1995-03-01

    This paper describes some of the applications of powder diffraction using synchrotron radiation with possible applications to industry. The advantages of differing synchrotron diffraction geometries, Debye-Scherrer, Analyser crystal, Hart Parrish, and Energy Dispersive, are discussed. The paper is not a comprehensive review but nevertheless considers the wider role of these powder diffraction geometries in elucidating crystal structures, highlighted examples being taken from polymers, catalyst and new drug materials, in addition to specific studies on polymer electrolyte complexes, textured materials (e.g. asbestos), pyrochlores, zeolites and cements. In the latter two cases rapid time-resolved powder diffraction is seen to be emerging as an important development in synchrotron-based techniques.

  17. Development of budesonide nanocluster dry powder aerosols: formulation and stability.

    PubMed

    El-Gendy, Nashwa; Huang, Shan; Selvam, Parthiban; Soni, Pravin; Berkland, Cory

    2012-09-01

    The physical and chemical stability of dry powder aerosol formulations is an essential component in the development of an inhaled therapeutic. The pharmaceutical processing methods and storage conditions are primary determinants of the stability of a dry powder inhaler (DPI) formulation. Wet milling was used to produce budesonide NanoClusters (NCs), which are agglomerates of drug nanoparticles (? 300 nm) with a mean aerodynamic diameter between 1 and 3 µm, capable of deep lung penetration. In this study, the reproducibility of NC processing and performance was established. The physical stability of a selected budesonide NC formulation was investigated using industry standard dose content uniformity and cascade impaction techniques. The chemical stability of the lead formulation was also determined as a function of processing parameters and storage conditions. This study confirms the reproducibility and robust stability of NC powders as a novel means to turn drug particles into high-performance aerosols. PMID:22619045

  18. Surface carbon films on Al-Cu-Fe quasicrystalline powders

    SciTech Connect

    Bloomer, T.E.; Flumerfelt, J.; Kramer, M.J.

    1996-12-31

    In order to study the unique properties of quasicrystals, it is necessary to form dense, homogeneous monoliths of these alloys. Unfortunately, Al-Cu-Fe quasicrystalline alloy ingots prepared by conventional casting techniques result in large scale chemical inhomogeneities which contain numerous cracks due to differential thermal contraction between the various phases during cooling. Thus a powder metallurgical approach using gas atomized (GA) powders is being pursued in order to form large samples of phase pure Al-Cu-Fe quasicrystal. A samples of specific compositions and sizes are hot isostatic pressed (HIPed) to form dense monoliths. The effects of surface contamination of GA powders, which may inhibit particle-to-particle sintering and may also increase second phase contamination in the HIPed piece, is being studied by scanning Auger microprobe (SAM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

  19. Influence of binders on infrared laser ablation of powdered tungsten carbide pressed pellets in comparison with sintered tungsten carbide hardmetals studied by inductively coupled plasma atomic emission spectrometry

    Microsoft Academic Search

    Markéta Holá; Vítezslav Otruba; Viktor Kanický

    2006-01-01

    Laser ablation (LA) was studied as a sample introduction technique for the analysis of powdered and sintered tungsten carbides (WC\\/Co) by inductively coupled plasma optical emission spectrometry (ICP–OES). The possibility to work with powdered and compact materials with close chemical composition provided the opportunity to compare LA sampling of similar substances in different forms that require different preparation procedures. Powdered

  20. Taking It to Extremes - Powder Diffraction Under Non-Ambient Conditions

    NASA Astrophysics Data System (ADS)

    Millar, David I. A.; Pulham, Colin R.

    Structural studies of materials under elevated pressures provide a fascinating insight into the physical and chemical behaviour of matter under the wide range of conditions experienced throughout the Universe. Both x-ray and neutron powder diffraction techniques play a crucial role in structural studies and are therefore at the forefront of high-pressure research. These notes provide a short introduction to the principles and experimental practice of high-pressure powder diffraction techniques.

  1. DC Plasma Technology Applied to Powder Metallurgy: an Overview

    NASA Astrophysics Data System (ADS)

    N. Klein, A.; P. Cardoso, R.; C. Pavanati, H.; Binder, C.; M. Maliska, A.; Hammes, G.; Fusao, D.; Seeber, A.; F. Brunatto, S.; L. R. Muzart, J.

    2013-01-01

    DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy (PM) and powder injection molding (PIM) parts production, are low-pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.

  2. Effect of IN718 Recycled Powder Reuse on Properties of Parts Manufactured by Means of Selective Laser Melting

    NASA Astrophysics Data System (ADS)

    Ardila, L. C.; Garciandia, F.; González-Díaz, J. B.; Álvarez, P.; Echeverria, A.; Petite, M. M.; Deffley, R.; Ochoa, J.

    Powder quality control is essential to obtain parts with suitable mechanical properties in Selective Laser Melting manufacturing technique. One of the most important advantages of suchtechnique is that it allows an efficient use of the material, due to the possibility to recycle and reuse un-melted powder. Nevertheless, powder material properties may change due to repeated recycling, affecting this way the mechanicalbehavior of parts. In this paper the effect of powder reuse on its quality and on the mechanical properties of the resulting melted parts is studied via self-developed recycling methodology. The material considered for investigation was IN718, a nickel superalloy widely used in industry. After recycling powder up to 14 times, no significant changes were observed in powder and test parts properties. The results obtained in this work will help to validate powder recycling methodology for its use in current industrial Selective Laser Melting manufacturing.

  3. 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 21?m 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 4?M18kOe=11.3kG, 4?Mr=11kG, and Hci>20kOe with a smooth demagnetization curve.

  4. Polymer quenched prealloyed metal powder

    DOEpatents

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

    2001-01-01

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

  5. Intradermal needle-free powdered drug injection

    E-print Network

    Liu, John (John Hsiao-Yung)

    2012-01-01

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

  6. Review: aqueous tape casting of ceramic powders

    Microsoft Academic Search

    D. Hotza; P. Greil

    1995-01-01

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

  7. Structural color painting by rubbing particle powder.

    PubMed

    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

  8. 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

  9. 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.

  10. Synchrotron X-Ray Powder Diffraction

    NASA Astrophysics Data System (ADS)

    Gozzo, Fabia

    The large breadth of the Synchrotron Radiation X-ray Powder Diffraction (SR-XRPD) technique inevitably requires that we make a certain number of choices in its discussion. Assuming you already have some knowledge of SR and XRPD, we explore the peculiar features that arise from combining them. From the perspective of a beamline scientist, we discuss aspects influencing the beamline optics, diffractometer, detectors and sample environments with attention to details important to perform outstanding SR-XRPD experiments. We begin with a brief overview of SR characteristics and properties and finish with a few SR-XRPD highlights. An extensive literature citation is provided for those who want to delve deeper into those topics that are inevitably not completely covered here.

  11. 21 CFR 524.1005 - Furazolidone powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Furazolidone powder. 524.1005 Section 524... § 524.1005 Furazolidone powder. (a) Specifications...affected area and apply only enough powder to impart a light yellow color...lacerations, and following firing (heat or electrocautery)....

  12. Agglomeration of Food Powder and Applications

    Microsoft Academic Search

    K. Dhanalakshmi; S. Ghosal; S. Bhattacharya

    2011-01-01

    Agglomeration has many applications in food processing and major applications include easy flow table salt, dispersible milk powder and soup mix, instant chocolate mix, beverage powder, compacted cubes for nutritional-intervention program, health bars using expanded\\/puffed cereals, etc. The main purpose of agglomeration is to improve certain physical properties of food powders such as bulk density, flowability, dispersability, and stability. Agglomerated

  13. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  14. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Copper powder. 73.1647 Section 73.1647...FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing...

  15. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Copper powder. 73.1647 Section 73.1647...FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing...

  16. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Copper powder. 73.1647 Section 73.1647...FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing...

  17. 21 CFR 73.1647 - Copper powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Copper powder. 73.1647 Section 73.1647...FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing...

  18. Effect of Powder Polydispersity on Aerosol Generation

    Microsoft Academic Search

    Nora Y. K. Chew; Hak-Kim Chan

    Purpose. We investigated the effect of primary powder polydispersity on the generation of pharmaceutical powder aerosols, using mannitol and bovine serum albu- min (BSA) as the model compounds. Methods. Primary powders with different polydispersity but comparable physical and mass median aerodynamic diameter (MMAD) were obtained from spray drying. The polydispersity, i.e. the width of the particle size distribution, of the

  19. Rapid detection of Bacillus anthracis spores directly from powders with an evanescent wave fiber-optic biosensor.

    PubMed

    Tims, T Bryan; Lim, Daniel V

    2004-10-01

    There currently are no rapid, sensitive tests to directly and reliably detect Bacillus anthracis spores in common powders. Traditional culture is time consuming and molecular techniques cannot directly process powders. This study describes a biosensor assay that detects B. anthracis at concentrations of 3.2 x 10(5) spores/mg or higher in spiked powders in less than 1 h with minimal sample preparation. PMID:15325759

  20. Treatment of refractory powders by a novel, high enthalpy dc plasma

    NASA Astrophysics Data System (ADS)

    Pershin, L.; Mitrasinovic, A.; Mostaghimi, J.

    2013-06-01

    Thermophysical properties of CO2-CH4 mixtures at high temperatures are very attractive for materials processing. In comparison with argon, at the same temperature, such a mixture possesses much higher enthalpy and higher thermal conductivity. At high temperatures, CO2-CH4 mixture has a complex composition with strong presence of CO which, in the case of powder treatment, could reduce oxidation. In this work, a dc plasma torch with graphite cathode was used to study the effect of plasma gas composition on spheroidization of tungsten carbide and alumina powders. Two different gas compositions were used to generate the plasma while the torch current was kept at 300 A. Various techniques were employed to assess the average concentration of carbides and oxides and the final shape of the treated powders. Process parameters such as input power and plasma gas composition allow controlling the degree of powder oxidation and spheroidization of high melting point ceramic powders.

  1. Preliminary attempt at sintering an ultrafine alumina powder using microwaves. Master's thesis

    SciTech Connect

    Alhambra, E.M.

    1994-09-01

    A commercially available microwave oven was used to sinter ultrafine alumina powders (0.02 - 0.05 micrometers particle size) with and without CaO sintering aid. The oven was modified by inserting a thermocouple probe through the bottom housing, and thoroughly insulating the interior with insulating material. The oven was placed in a glove box and filled with argon to prevent degradation of the thermocouple, and oxidation of the powdered graphite susceptor. Heating rates of 50-75 Deg C/sec with a maximum temperature of 1575 Deg C were obtained. Limited success in sintering of the the powder compacts was achieved in this preliminary effort. The microstructures of the sintered products were examined by scanning electron microscopy. It was concluded that further work is necessary to develop this technique into one which can be used for the routine sintering of fine powdered ceramic material. A review of the literature on microwave sintering of ceramic powders is also reported.

  2. Powder Diffraction from a Continuous Micro-Jet of sub-micron Protein Crystals

    E-print Network

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

    2008-01-01

    Powder diffraction rings have been obtained from sub-micron protein crystallites in a water jet, and the data analysed. Previous powder diffraction has used a suspension of small crystallites, and long exposures, causing significant X-ray damage. We show here that protein powder data from nano-crystals can be obtained using a continuous micro-jet. This allows more efficient use of crystal growth solutions containing nanocrystals and the much shorter exposures needed for next-generation synchrotrons. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryo-cooling. We have commissioned an apparatus to record protein powder diffraction in this manner and in this paper present the first such patterns from photosystem I protein crystals with sizes less than 500 nm. These preliminary patterns show the lowest order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results serve also to test ou...

  3. MESOSCALE SIMULATIONS OF POWDER COMPACTION

    SciTech Connect

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

    2009-12-28

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

  4. Particle adhesion in powder coating

    SciTech Connect

    Mazumder, M.K.; Wankum, D.L.; Knutson, M.; Williams, S. [Univ. of Arkansas, Little Rock, AR (United States); Banerjee, S. [Univ. of Georgia, Athens, GA (United States)

    1996-12-31

    Electrostatic powder coating is a widely used industrial painting process. It has three major advantages: (1) it provides high quality durable finish, (2) the process is environmentally friendly and does not require the use of organic solvents, and (3) it is economically competitive. The adhesion of electrostatically deposited polymer paint particles on the grounded conducting substrate depends upon many parameters: (a) particle size and shape distributions, (b) electrostatic charge distributions, (c) electrical resistivity, (d) dielectric strength of the particles, (e) thickness of the powder film, (f) presence and severity of the back corona, and (g) the conductivity and surface properties of the substrate. The authors present a model on the forces of deposition and adhesion of corona charged particles on conducting substrates.

  5. Analysis of powder diffraction data

    Microsoft Academic Search

    M. J. Cooper

    1982-01-01

    A comparison has been carried out between the results of analyses of several sets of neutron powder diffraction data using three different methods: the Rietveld method (H.M. Rietveld, Acta. Cryst. 2, 151-152 (1967): J. Appl. Cryst. 2, 65-71 (1969), a modification of the Rietveld method to include off-diagonal terms in the weight matrix (C.P. Clarke and J.S. Rollett, Acta. Cryst.

  6. Anti-Corrosive Powder Particles

    NASA Technical Reports Server (NTRS)

    Parker, Donald; MacDowell, Louis, III

    2005-01-01

    The National Aeronautics and Space Administration (NASA) seeks partners for a new approach in protecting embedded steel surfaces from corrosion. Corrosion of reinforced steel in concrete structures is a significant problem for NASA structures at Kennedy Space Center (KSC) because of the close proximity of the structures to salt spray from the nearby Atlantic Ocean. In an effort to minimize the damage to such structures, coatings were developed that could be applied as liquids to the external surfaces of a substrate in which the metal structures were embedded. The Metallic Pigment Powder Particle technology was developed by NASA at KSC. This technology combines the metallic materials into a uniform particle. The resultant powder can be sprayed simultaneously with a liquid binder onto the surface of concrete structures with a uniform distribution of the metallic pigment for optimum cathodic protection of the underlying steel in the concrete. Metallic Pigment Powder Particle technology improves upon the performance of an earlier NASA technology Liquid Galvanic Coating (U.S. Patent No. 6,627,065).

  7. Mechanical properties and shear failure surfaces of two alumina powders in triaxial compression

    SciTech Connect

    ZEUCH,DAVID H.; GRAZIER,J. MARK; ARGUELLO JR.,JOSE G.; EWSUK,KEVIN G.

    2000-04-24

    In the manufacture of ceramic components, near-net-shape parts are commonly formed by uniaxially pressing granulated powders in rigid dies. Density gradients that are introduced into a powder compact during press-forming often increase the cost of manufacturing, and can degrade the performance and reliability of the finished part. Finite element method (FEM) modeling can be used to predict powder compaction response, and can provide insight into the causes of density gradients in green powder compacts; however, accurate numerical simulations require accurate material properties and realistic constitutive laws. To support an effort to implement an advanced cap plasticity model within the finite element framework to realistically simulate powder compaction, the authors have undertaken a project to directly measure as many of the requisite powder properties for modeling as possible. A soil mechanics approach has been refined and used to measure the pressure dependent properties of ceramic powders up to 68.9 MPa (10,000 psi). Due to the large strains associated with compacting low bulk density ceramic powders, a two-stage process was developed to accurately determine the pressure-density relationship of a ceramic powder in hydrostatic compression, and the properties of that same powder compact under deviatoric loading at the same specific pressures. Using this approach, the seven parameters that are required for application of a modified Drucker-Prager cap plasticity model were determined directly. The details of the experimental techniques used to obtain the modeling parameters and the results for two different granulated alumina powders are presented.

  8. Micro powder metallurgy for the replicative production of metallic microstructures

    Microsoft Academic Search

    A. Rota; T. V. Duong; T. Hartwig

    2002-01-01

    Reproductive techniques like injection molding or embossing of feedstock provide microstructures of a wide variety of materials\\u000a for a reasonable price to micro system technology. In this paper, the dependencies and barriers to produce high aspect ratio\\u000a structures by micro metal injection molding are described; some results of embossing of metal powder based feedstocks are\\u000a presented, too. The investigations show

  9. In situ characterization of AIPO-14 using synchrotron powder diffraction

    Microsoft Academic Search

    N. Yang; N. Greenlay; J. Karapetrova; P. Zschack; M. Gatter; S. Wilson; R. W. Broach

    2006-01-01

    The separation of propane\\/propylene mixtures is an important yet difficult industrial process that can be accomplished by a pressure swing adsorption process using AlPO-14 as the adsorbent. Although the AlPO-14 structure has been studied with different techniques, the detailed structure under conditions of the adsorption process has not been clarified. We have used synchrotron x-ray powder diffraction and an in

  10. Advances in powder metallurgy of soft magnetic materials

    Microsoft Academic Search

    Christopher G. Oliver

    1995-01-01

    This paper discusses two new powder metallurgy processes that provide increased soft magnetic performance over conventional techniques. The first is a process involving elevated compaction temperatures which enable sintered densities of 7.59 g\\/cm3 for iron containing 0.35% by weight of phosphorus. Maximum permeabilities exceeding 6,000 with saturation inductions of 19,730 G are typical results utilizing this process. The second process

  11. Evaluation of Factors Affecting Powdered Drug Reconstitution in Microgravity

    NASA Technical Reports Server (NTRS)

    Schaffner, Grant; Johnston, Smith; Marshburn, Tom

    1999-01-01

    Owing to the high cost of transporting mass into space, and the small volume available for equipment in the Space Shuttle Orbiter and the International Space Station, refrigeration space is extremely limited. For this reason, there exists strong motivation for transporting certain drugs in powdered form so that they do not require refrigeration. When needed, the powdered drug will be mixed with saline to obtain a liquid form that may be injected intravenously. While this is a relatively simple task in a 1-G environment, there are some difficulties that may be encountered in 0-G. In non-accelerated spaceflight, gravitational and inertial forces are eliminated allowing other smaller forces, such as capillary forces and surface tension, to dominate the behavior of fluids. For instance, water slowly ejected from a straw will tend to form a sphere, while fluid in a container will tend to wet the inside surface forming a highly rounded meniscus. Initial attempts at mixing powdered drugs with saline in microgravity have shown a tendency toward forming foamy emulsions instead of the desired homogeneous solution. The predominance of adhesive forces between the drug particles and the interface tensions at the gas/liquid and solid/liquid interfaces drastically reduce the rate of deaggregation of the drug powder and also reduce the rate of absorption of saline by the powder mass. In addition, the capillary forces cause the saline to wet the inside of the container, thus trapping air bubbles within the liquid. The rate of dissolution of a powder drug is directly proportional to the amount of surface area of the solid that is exposed to liquid solvent. The surface area of drug that is in contact with the liquid is greatly reduced in microgravity and, as a result, the dissolution rate is reduced as well. The KC-135 research described here was aimed at evaluating the extent to which it is possible to perform drug reconstitution in the weightlessness of parabolic flight using standard pharmacological supplies. The experiment included a parametric assessment of possible factors affecting the reconstitution process. The specific questions that we wished to answer were: (1) Is it possible to reconstitute powdered drugs in weightlessness using standard pharmacological equipment? (2) What are the differences between drug reconstitution in a 1-G and a 0-G environment? (3) What techniques of mixing the drug powder and diluent are more successful? (4) What physical and chemical factors play a role in determining the success of mixing and dissolution? (5) Is it necessary to employ crewmember and equipment restraints during the reconstitution process?

  12. Interparticle force based methodology for prediction of cohesive powder flow properties

    NASA Astrophysics Data System (ADS)

    Esayanur, Madhavan Sujatha Sarma

    The transport and handling of powders are key areas in the process industry that have a direct impact on the efficiency and/or the quality of the finished product. A lack of fundamental understanding of powder flow properties as a function of operating variables such as relative humidity, and particle size, leading to problems such as arching, rat-holing and segregation, is one the main causes for unscheduled down times in plant operation and loss of billions of dollars in revenues. Most of the current design strategies and characterization techniques for industrial powders are based on a continuum approach similar to the field of soil mechanics. Due to an increase in complexity of the synthesis process and reduction in size of powders to the nanoscale, the surface properties and inter particle forces play a significant role in determining the flow characteristics. The use of ensemble techniques such as direct shear testing to characterize powders are no longer adequate due to lack of understanding of the changes in the property of powders as a function of the major operating variables such as relative humidity, temperature etc. New instrumentation or techniques need to be developed to reliably characterize powder flow behavior. Simultaneously, scalability of the current models to predict powder flow needs to be revisited. Specifically, this study focuses on the development of an inter particle force based model for predicting the unconfined yield strength of cohesive powders. To understand the role of interparticle forces in determining the strength of cohesive powders, the particle scale interactions were characterized using Atomic Force Microscopy (AFM), contact angle, surface tension, and coefficient of friction. The bulk scale properties such as unconfined yield strength, packing structure, and size of the shear zone were also investigated. It was determined that an interparticle force based model incorporating the effect of particle size and packing structure leads to a reasonable prediction of the bulk strength of cohesive powders. Additionally, the role of particle size distribution and liquid distribution in the powder was considered. The findings of this research should be helpful to the practitioners in providing reliable input for the design of cohesive powder flow and handling equipment.

  13. The effects of powder properties on in-flight particle velocity and deposition process during low pressure cold spray process

    Microsoft Academic Search

    Xian-Jin Ning; Jae-Hoon Jang; Hyung-Jun Kim

    2007-01-01

    In cold spray process, impacting velocity and critical velocity of particles dominate the deposition process and coating properties for given materials. The impacting velocity and critical velocity of particles depend on the powder properties and cold spray conditions. In the present study, the in-flight particle velocity of copper powder in low pressure cold spraying was measured using an imaging technique.

  14. Synthesis of yttrium aluminum garnet (YAG) powder by homogeneous precipitation combined with supercritical carbon dioxide or ethanol fluid drying

    Microsoft Academic Search

    Yang Ru; Qin Jie; Li Min; Liu Guoqiang

    2008-01-01

    YAG precursors were synthesized by the urea method in aqueous solution using supercritical carbon dioxide and ethanol fluid drying technique, respectively. The composition of the precursors, the phase formation process and the properties of the calcined powders were investigated by means of XRD, IR, TG\\/DSC, BET, TEM and SEM. Compared with the classically prepared powders at room temperature in air,

  15. Experimental investigation of design parameters on dry powder inhaler performance.

    PubMed

    Ngoc, Nguyen Thi Quynh; Chang, Lusi; Jia, Xinli; Lau, Raymond

    2013-11-30

    The study aims to investigate the impact of various design parameters of a dry powder inhaler on the turbulence intensities generated and the performance of the dry powder inhaler. The flow fields and turbulence intensities in the dry powder inhaler are measured using particle image velocimetry (PIV) techniques. In vitro aerosolization and deposition a blend of budesonide and lactose are measured using an Andersen Cascade Impactor. Design parameters such as inhaler grid hole diameter, grid voidage and chamber length are considered. The experimental results reveal that the hole diameter on the grid has negligible impact on the turbulence intensity generated in the chamber. On the other hand, hole diameters smaller than a critical size can lead to performance degradation due to excessive particle-grid collisions. An increase in grid voidage can improve the inhaler performance but the effect diminishes at high grid voidage. An increase in the chamber length can enhance the turbulence intensity generated but also increases the powder adhesion on the inhaler wall. PMID:24055597

  16. Dry powders for oral inhalation free of lactose carrier particles.

    PubMed

    Healy, Anne Marie; Amaro, Maria Inês; Paluch, Krzysztof J; Tajber, Lidia

    2014-08-01

    Dry powder inhaler (DPI) products have traditionally comprised a simple formulation of micronised drug mixed with a carrier excipient, typically lactose monohydrate. The presence of the carrier is aimed at overcoming issues of poor flowability and dispersibility, associated with the cohesive nature of small, micronised active pharmaceutical ingredient (API) particles. Both the powder blend and the DPI device must be carefully designed so as to ensure detachment of the micronised drug from the carrier excipient on inhalation. Over the last two decades there has been a significant body of research undertaken on the design of carrier-free formulations for DPI products. Many of these formulations are based on sophisticated particle engineering techniques; a common aim in formulation design of carrier-free products being to reduce the intrinsic cohesion of the particles, while maximising dispersion and delivery from the inhaler. In tandem with the development of alternative formulations has been the development of devices designed to ensure the efficient delivery and dispersion of carrier-free powder on inhalation. In this review we examine approaches to both the powder formulation and inhaler design for carrier-free DPI products. PMID:24735676

  17. Development of liposomal salbutamol sulfate dry powder inhaler formulation.

    PubMed

    Huang, Wen-Hua; Yang, Zhi-Jun; Wu, Heng; Wong, Yuen-Fan; Zhao, Zhong-Zhen; Liu, Liang

    2010-01-01

    The purpose of our study was to develop a formulation of liposomal salbutamol sulfate (SBS) dry powder inhaler (DPI) for the treatment of asthma. Liposomes of high encapsulation efficiency (more than 80%) were prepared by a vesicular phospholipid gel (VPG) technique. SBS VPG liposomes were subjected to lyophilization using different kinds of cryoprotectants in various mass ratios. Coarse lactose (63-106 microm) in different mass ratios was used as a carrier. Magnesium stearate (0.5%) was added as a lubricator. The dry liposomal powders were then crushed by ball milling and sieved through a 400-mesh sieve to control the mean particle size at about 10 microm. The effects of different kinds of cryoprotectants and the amount of lactose carrier on the fine particle fraction (FPF) of SBS were investigated. The results showed that the developed formulation of liposomal dry powder inhaler was obtained using lactose as a cryoprotectant with a mass ratio of lyophilized powder to carrier lactose at 1 : 5; 0.5% magnesium stearate was used as a lubricator. The value of FPF for SBS was 41.51+/-2.22% for this formulation. Sustained release of SBS from the VPG liposomes was found in the in vitro release study. The study results offer the promising possibility of localized pulmonary liposomal SBS delivery in the anhydrous state. PMID:20190418

  18. Preparation, characterization and photocatalytic properties of ZnTiO 3 powders

    Microsoft Academic Search

    Ji-Zhou Kong; Ai-Dong Li; Hai-Fa Zhai; Hui Li; Qing-Yu Yan; Jan Ma; Di Wu

    2009-01-01

    A novel photocatalyst ZnTiO3 powder was prepared by a modified alcoholysis method, using ethylene glycol as reagent\\/solvent and acetylacetone as stabilizer. A series of analytical techniques were used to characterize the crystallinity, composition, bandgap, morphology, specific surface area and grain size of ZnTiO3 powders. The relationship between the physicochemical property and the photocatalytic activity was deeply investigated, too. It is

  19. Grinding Si3N4 Powder In Si3N4 Equipment

    NASA Technical Reports Server (NTRS)

    Herbell, Thomas P.; Freedman, Marc R.; Kiser, James D.

    1989-01-01

    Three methods of grinding compared. Report based on study of grinding silicon nitride powder in preparation for sintering into solid ceramic material. Attrition, vibratory, and ball mills lined with reaction-bonded silicon nitride tested. Rates of reduction of particle sizes and changes in chemical compositions of powders measured so grinding efficiences and increases in impurity contents from wear of mills and media evaluated for each technique.

  20. Macroporous glass monoliths prepared from powdered niobium phosphate glass by fast sintering

    Microsoft Academic Search

    Vitor Lacerda Mauricio; Oswaldo Luiz Alves; Italo Odone Mazali

    2011-01-01

    Macroporous monoliths were prepared by very fast sintering (between 3 and 15min) of niobophosphate glass powders at low temperature (1018K) using cellulose as a foaming agent. The porous materials were analyzed by thermal analysis, Raman spectroscopy, scanning electron microscopy and powder X-ray diffraction, and further investigated using X-ray microtomography, a non-destructive technique capable of reconstructing three-dimensional models of samples and

  1. Gold powder: Its preparation & application as described in ancient Sanskrit texts

    Microsoft Academic Search

    R. K. Dube

    1991-01-01

    In this article the origin and development of the technology of gold powder in ancient India is described on the basis of\\u000a the literary evidence cited in various Sanskrit texts. The applications of gold powder as described in these texts are also\\u000a discussed.\\u000a \\u000a \\u000a Basically two techniques — mechanical comminution and chemical methods — were used in Indian antiquity for making

  2. Synthesis of high purity carbide powders. (Latest citations from Engineered Materials abstracts). Published Search

    SciTech Connect

    Not Available

    1994-08-01

    The bibliography contains citations concerning the synthesis and preparation of high purity carbide powders. Articles discuss techniques of powder manufacture such as chemical vapor deposition, plasma arc reactions, sintering, hot pressing, combustion synthesis, precipitation, chemical reaction, self-propagating high temperature synthesis, shock or explosive compaction, and aerosol formation. Citations concern silicon carbides, titanium carbides, and other carbide materials and composites. (Contains 250 citations and includes a subject term index and title list.)

  3. Defect structures in zirconium diboride powder prepared by self-propagating high-temperature synthesis

    Microsoft Academic Search

    S. K. Mishra; S. Das; L. C. Pathak

    2004-01-01

    A comparative study on the defect structures in zirconium diboride (ZrB2) powder prepared by three different techniques namely a self-propagating high-temperature synthesis (SHS), a replacement reaction process (RRP) and a carbothermic reduction process (CRP) was carried out. It was established that the powder prepared by SHS process has more defect structures due to strongly higher rate of heating and cooling

  4. In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

    PubMed

    Ning, C Q; Zhou, Y

    2002-07-01

    Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite. PMID:12069332

  5. Process for the synthesis of iron powder

    DOEpatents

    Welbon, W.W.

    1983-11-08

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

  6. Process for the synthesis of iron powder

    DOEpatents

    Not Available

    1982-03-06

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

  7. Stereochemistry Determination by Powder X-ray Diffraction Analysis and NMR Spectroscopy Residual Dipolar Couplings

    SciTech Connect

    Garcia, M.; Pagola, S; Navarro-Vasquez, A; Phillips, D; Gayathri, C; Krakauer, H; Stephens, P; Nicotra, V; Gil, R

    2009-01-01

    A matter of technique: For a new steroidal lactol, jaborosalactol 24 (1), isolated from Jaborosa parviflora, NMR spectroscopy residual dipolar couplings and powder X-ray diffraction analysis independently gave the same stereochemistry at C23-C26. Conventional NMR spectroscopic techniques, such as NOE and {sup 3}J coupling-constant analysis failed to unambiguously determine this stereochemistry.

  8. Thixoforming of Stellite Powder Compacts

    NASA Astrophysics Data System (ADS)

    Hogg, S. C.; Atkinson, H. V.; Kapranos, P.

    2007-04-01

    Thixoforming involves processing metallic alloys in the semi-solid state. The process requires the microstructure to be spheroidal when part-solid and part-liquid i.e. to consist of solid spheroids surrounded by liquid. The aim of this work was to investigate whether powder compacts can be used as feedstock for thixoforming and whether the consolidating pressure in the thixoformer can be used to remove porosity from the compact. The powder compacts were made from stellite 6 and stellite 21 alloys, cobalt-based alloys widely used for e.g. manufacturing prostheses. Isothermal heat treatments of small samples in the consolidated state showed the optimum thixoforming temperature to be in the range 1340°C-1350°C for both materials. The alloys were thixoformed into graphite dies and flowed easily to fill the die. Porosity in the thixoformed components was lower than in the starting material. Hardness values at various positions along the radius of the thixoformed demonstrator component were above the specification for both alloys.

  9. Synthesis of mullite powders by acrylamide polymerization.

    SciTech Connect

    Sin, A.; Picciolo, J. J.; Lee, R. H.; Gutierrez-Mora, F.; Goretta, K. C.; Energy Technology; INPG-CNRS

    2001-09-01

    Mullite (3Al{sub 2}O{sub 3} {center_dot} 2SiO{sub 2}) ceramics and composites are widely used. Synthesis of mullite powders, especially those that can be readily sintered, remains a focus of much current research. In support of recent efforts to fabricate mullite fibrous monoliths and to use superplastic flow to join ceramics, we have looked to synthesize reactive mullite powders. Recent advances in application of acrylamide polymers to ceramic synthesis offer promise of obtaining large quantities of high-quality powder at relatively low cost. We report here on synthesis from acrylamide monomers of mullite powders of two interesting particle sizes.

  10. Dendritic microstructure in argon atomized superalloy powders

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Kumar, Mahundra

    1986-01-01

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

  11. Frequency domain photon migration measurements: a method to size powders and detect active pharmaceutical ingredients in blending operations 

    E-print Network

    Torrance, Sharnay Etasha

    2004-01-01

    of powder-based therapeutic products has come under scrutiny causing manufacturers to strive toward alternative solutions to their traditional validation methods. This thesis presents an optical technique, frequency domain photon migration (FDPM), as a...

  12. Frequency domain photon migration measurements: a method to size powders and detect active pharmaceutical ingredients in blending operations

    E-print Network

    Torrance, Sharnay Etasha

    2004-01-01

    means for process validation in the manufacture of solid pharmaceutics through its ability to characterize powder ingredients by particle size and ingredient composition. In this work, FDPM analysis techniques were utilized to extract particle size...

  13. The Effect of Powder Recycling in Direct Metal Laser Deposition on Powder and Manufactured Part Characteristics

    Microsoft Academic Search

    P. A. Carroll; A. J. Pinkerton; J. Allen; W Syed; H Sezer; P. Brown; G. Ng; L. Li

    A potential way of improving the material efficiency and cost effectiveness of the Direct Metal Laser Deposition (DMLD) process is to take powder that is not utilised in each deposition attempt and re-use it in subsequent attempts (powder recycling). Currently, this is not widely implemented for fear of a detrimental effect on part quality. This study examines how powder recycling,

  14. Density-permittivity relationships for powdered and granular materials

    SciTech Connect

    Nelson, S.O. [USDA ARS, Athens, GA (United States). Russell Research Center

    2005-10-01

    Relationships between the permittivities of powdered or granular solid materials and their bulk densities (density of the air-particle mixture) are discussed. Linear relationships between functions of the permittivity and bulk density are identified that are useful in determining permittivity of solids from measurements of the permittivity of pulverized samples. The usefulness of several dielectric mixture equations for calculating solid material permittivity from measured permittivity of pulverized samples is also discussed. Results of testing linear extrapolation techniques and dielectric mixture equations on pulverized coal, limestone, plastics, and granular wheat and flour are presented. Recommendations are provided for reliable estimation of solid material permittivities or changes in permittivities of powdered and granular materials as a result of changes in their bulk densities.

  15. An evaluation of the anti-bacterial action of ceramic powder slurries using multi-parameter flow cytometry

    Microsoft Academic Search

    Christopher J. Hewitt; Sanjay R. Bellara; Andrea Andreani; Gerhard Nebe-von-Caron; Caroline M. McFarlane

    2001-01-01

    Multi-parameter flow cytometric techniques have been used to study the effects of three ceramic powders CaO, MgO and ZnO on the physiology of individual, exponentially growing E. coli cells. Whilst all three powders inhibited reproductive growth, depending on their concentration, the mechanism of action of CaO and MgO was different to that of ZnO as shown by fluorescent staining techniques

  16. The preparation and properties of glass powder reinforced epoxy resin

    Microsoft Academic Search

    Haifeng Wang; Wenjue Han; Haibing Tian; Yimin Wang

    2005-01-01

    A sealing composites were prepared by mixing superfine glass powder and epoxy resin. The effect of active agent (stearate) on glass powder size and size distribution and the effect of surface treatment of the glass powder on the microstructure and the mechanical properties of glass powder\\/epoxy composites were investigated. Glass powder size was measured using a laser particle size analyzer.

  17. Slip casting and nitridation of silicon powder

    NASA Technical Reports Server (NTRS)

    Seiko, Y.

    1985-01-01

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

  18. In-line powder coating of pultrusions

    SciTech Connect

    Spoo, K. [Owens-Corning, Granville, OH (United States); Smith, G. [Owens-Corning, Hazleton, PA (United States)

    1996-11-01

    This paper discusses the pros and cons of an in-line powder coating process that applies an acrylic modified polyurethane powder to pultruded window lineals. The system applies the finish to the pultruded part downstream from the pultrusion die. Capital costs, direct costs, and mechanics of the process are discussed.

  19. Electrical Resistivity of Metal Powder Aggregates

    Microsoft Academic Search

    J. M. Montes; F. G. Cuevas; J. Cintas

    2007-01-01

    An equation for calculating the electrical resistivity of a compressed powder mass, consisting of oxide-coated metal particles, has been derived. In addition to the intrinsic interest of the problem, the proposed equation is useful for describing the very early stages of electrical sintering processes. The problem is approached in a new way, relating the actual powder system to an equivalent

  20. Numerical Simulation of Aerated Powder Consolidation1

    E-print Network

    will slowly escape by diffusing through the material. The corresponding uneven gas pressure distribution properties. Over time the excess air diffuses through the powder and eventually escapes through the top systems for the vertical conical bunker. The height of the column of powder of time ¡ is denoted

  1. Process for the synthesis of iron powder

    Microsoft Academic Search

    Welbon

    1983-01-01

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

  2. Modeling of microwave heating of metallic powders

    Microsoft Academic Search

    V. D. Buchelnikov; D. V. Louzguine-Luzgin; A. P. Anzulevich; I. V. Bychkov; N. Yoshikawa; M. Sato; A. Inoue

    2008-01-01

    As it is known from the experiment that bulk metallic samples reflect microwaves while powdered samples can absorb such a radiation and be heated efficiently. In the present paper we investigate theoretically the mechanisms of penetration of a layer of metallic powder by microwave radiation and microwave heating of such a system.

  3. Microwave heating of conductive powder materials

    Microsoft Academic Search

    K. I. Rybakov; V. E. Semenov; S. V. Egorov; A. G. Eremeev; I. V. Plotnikov; Yu. V. Bykov

    2006-01-01

    In recent years, a considerable interest has been drawn to microwave heating of powder metals and other electrically conductive materials. In this paper a consistent formulation describing the absorption of microwaves in electrically conductive materials under different microwave heating conditions is developed. A special case when conductive powder particles are surrounded by insulating oxide layers is investigated in detail using

  4. Thermal plasma chemical synthesis of powders

    SciTech Connect

    Vogt, G.J.; Newkirk, L.R.

    1985-01-01

    Thermal plasma processing has been increasingly used to synthesize submicron powders of high-purity ceramics and metals. The high temperatures generated with the plasma provide a vapor phase reaction zone for elements with high boiling points and refractory materials. An overview is presented on the general plasma technology used in synthesis and on the properties of plasma powders.

  5. Modeling nonelectrostatic and electrostatic powder coating

    Microsoft Academic Search

    Shantanu Yousuf; Sheryl A. Barringer

    2007-01-01

    The effect of particle size, density, charge and air velocity on transfer efficiency, evenness and separation of mixtures during powder coating was investigated using modeling and experimentation. Electrostatic and nonelectrostatic coating was tested using 28, 234 and 342?m NaCl and 195?m starch powders. Transfer efficiency increased as particle size, density or charge increased or as air velocity decreased. Evenness increased

  6. Physical and dielectric properties of pharmaceutical powders

    Microsoft Academic Search

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

    2003-01-01

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

  7. Powder Metallurgy Composite Materials Strengthened with Fibers

    Microsoft Academic Search

    Suren G. Agbalyan

    2001-01-01

    The extrusion dynamics of high-strength powder metallurgy composite materials was studied. The extrusion parameters for porous compacts of copper fibers and Cu ? Mo composites were optimized. It was shown that orientation of fibers is possible only when they are sufficiently widely dispersed in the powder matrix and also when the fiber length is much greater than its diameter l

  8. Insolubility of milk powder products A minireview

    E-print Network

    Boyer, Edmond

    of milk, at the beginning of the evaporation process, the whey proteins change their conformationReview Insolubility of milk powder products ­ A minireview Alan J. BALDWIN* Fonterra Research Abstract ­ In this paper, the formation of insolubility in milk powder is described, and the factors

  9. Nano-scale analysis of titanium dioxide fingerprint-development powders

    NASA Astrophysics Data System (ADS)

    Reynolds, A. J.; Jones, B. J.; Sears, V.; Bowman, V.

    2008-08-01

    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO2 particles and efficacy of print development.

  10. Wet powder seal for gas containment

    DOEpatents

    Stang, Louis G. (Sayville, NY)

    1982-01-01

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

  11. Nanostructured GGG powders via gel combustion

    NASA Astrophysics Data System (ADS)

    Li, Xianxue; Hu, Zhang-Gui; Li, Jiangtao

    2007-03-01

    Polycrystalline nano-sized gadolinium gallium garnet (Gd3Ga5O12, GGG) powders were synthesized via a gel combustion method from a mixed solution of Ga(NO3)3, Gd(NO3)3 and citric acid. The evolution of phase composition and micro-structure of the powders were characterized by X-ray powder diffraction, thermogravimetry/differential thermal analysis and scanning electron microscopy. Well-crystallized, single phase GGG nano-sized powders could be obtained at the calcining temperature as low as 750 °C for 2 h. No any intermediate phases formed during the calcining process. The resulting powders were well dispersed and had a relatively narrow size distribution with an average particle size of approximately 30-50 nm.

  12. Dense silica coatings on ceramic powder particles

    SciTech Connect

    Opitz, J.F.A.; Mayr, W. [Philips GmbH Forschungslaboratorien, Aachen (Germany)

    1995-09-01

    Dense silica coatings on the surface of inorganic powders particles are prepared by the hydrolysis of tetraethoxysilane (TEOS) in alcoholic suspensions. In a first reaction step, the TEOS is pre-hydrolysed in acidic solution and afterwards, a suspension of powder particles in this reaction solution is treated with ammonia which results in a dense silica coating of typically 10 - 100 nm thickness. Different luminescent powders which are used in the manufacture of cathode-ray tubes or fluorescent lamps have been coated by this procedure. The silica coating forms a transparent layer and the suspension properties of the coated powders are determined by the silica layer. The silica coating also protects sulfidic luminescent powders from being attacked by oxidizing agents like dichromate ions which are used in the suspension formulations for TV tube fabrication.

  13. Instability of bacteriophages in spray-dried trehalose powders is caused by crystallization of the matrix.

    PubMed

    Vandenheuvel, Dieter; Meeus, Joke; Lavigne, Rob; Van den Mooter, Guy

    2014-09-10

    Spray drying is a valuable technique in pharmaceutical dosage formulation, capable of producing amorphous, spherical powders, suitable for pulmonary deposition and further downstream processing. In this study, we show that spray drying bacteriophages together with trehalose results in an amorphous powder matrix with high glass transition temperature (between 116 and 118°C), typical for amorphous trehalose. These powders are stable at low temperatures (4°C) and relative humidity (0%). However, high humidity causes crystallization of the amorphous matrix, destroying the embedded phages. Furthermore, storage at higher temperature (25°C) causes thermal instability of the embedded phages. The results show that storage conditions are important parameters to take into account in phage therapy development. The resulting particles are hollow spheres, with suitable aerodynamic diameters for deposition into the deep lungs. This opens possibilities to use these phage-containing powder formulations to tackle pulmonary infectious diseases, especially caused by antibiotic resistant pathogens. PMID:24950368

  14. Investigation of NIR hyperspectral imaging for discriminating melamine in milk powder

    NASA Astrophysics Data System (ADS)

    Fu, Xiaping; Kim, Moon S.; Chao, Kuanglin; Qin, Jianwei; Lim, Jongguk; Lee, Hoyoung; Ying, Yibin

    2013-05-01

    Melamine (2,4,6-triamino-1,3,5-triazine) contamination of food has become an urgent and broadly recognized issue for which rapid and accurate identification methods are needed by the food industry. In this study, the feasibility and effectiveness of near-infrared (NIR) hyperspectral imaging was investigated for detecting melamine in milk powder. Hyperspectral NIR images (144 bands spanning from 990 to 1700 nm) were acquired for Petri dishes containing samples of milk powder mixed with melamine at various concentrations (0.02% to 1%). Spectral bands that showed the most significant differences between pure milk and pure melamine were selected, and two-band difference analysis was applied to the spectrum of each pixel in the sample images to identify melamine particles in milk powders. The resultant images effectively allowed visualization of melamine particle distributions in the samples. The study demonstrated that NIR hyperspectral imaging techniques can qualitatively and quantitatively identify melamine adulteration in milk powders.

  15. Applicability of Washburn capillary rise for determining contact angles of powders/porous materials.

    PubMed

    Kirdponpattara, Suchata; Phisalaphong, Muenduen; Newby, Bi-min Zhang

    2013-05-01

    The Washburn capillary rise (WCR) technique has been widely utilized for determining contact angles of powders or porous materials; however, there are concerns regarding powder size and powder packing, especially for materials that exhibit large contact angle hysteresis. In this paper, some of these concerns were addressed. Due to the large water contact angle hysteresis on flat nylon 6/6 films, these films were ground into powders of different sizes and then used as model packing materials. The powders were packed in glass tubes to result in various packing structures that affected the penetration (i.e. advancing) rate of the test liquids. While all advancing contact angles obtained from WCR were found to be overestimated, more reasonable values were resulted when relatively large powders (e.g. 500-2000 ?m) were used to pack the tubes. With larger powders, the packing contained bigger voids and consequently lead to slower penetration rates of the liquids, hence a relatively smaller advancing contact angle. The smaller advancing contact angle obtained from the slower advancing rate was also observed by using the sessile drop method. To verify the applicability of using large powders (500-2000 ?m) for contact angle determination by using WCR, the advancing water contact angles of a bacterial cellulose/alginate composite sponge (BCA) with and without UV/ozone treatment were measured. The results showed that by using relatively large powders, WCR could be applied to obtain a reasonable advancing contact angle and assess the wettability change of complex porous materials. PMID:23484765

  16. 21 CFR 524.1005 - Furazolidone aerosol powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...false Furazolidone aerosol powder. 524.1005 Section 524...1005 Furazolidone aerosol powder. (a) Specifications...affected area and apply only enough powder to impart a light yellow color...lacerations, and following firing (heat or electrocautery)....

  17. 21 CFR 524.1005 - Furazolidone aerosol powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...false Furazolidone aerosol powder. 524.1005 Section 524...1005 Furazolidone aerosol powder. (a) Specifications...affected area and apply only enough powder to impart a light yellow color...lacerations, and following firing (heat or electrocautery)....

  18. 21 CFR 524.1005 - Furazolidone aerosol powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...false Furazolidone aerosol powder. 524.1005 Section 524...1005 Furazolidone aerosol powder. (a) Specifications...affected area and apply only enough powder to impart a light yellow color...lacerations, and following firing (heat or electrocautery)....

  19. 30 CFR 75.1101-18 - Dry powder requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Resources 1 2010-07-01 2010-07-01 false Dry powder requirements. 75.1101-18 Section...COAL MINES Fire Protection § 75.1101-18 Dry powder requirements. Each dry powder chemical system shall contain the...

  20. 30 CFR 75.1101-18 - Dry powder requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Resources 1 2011-07-01 2011-07-01 false Dry powder requirements. 75.1101-18 Section...COAL MINES Fire Protection § 75.1101-18 Dry powder requirements. Each dry powder chemical system shall contain the...

  1. A comparative study of ZnS powders sintering by Hot Uniaxial Pressing (HUP) and Spark Plasma Sintering (SPS)

    Microsoft Academic Search

    C. Chlique; G. Delaizir; O. Merdrignac-Conanec; C. Roucau; M. Dollé; P. Rozier; V. Bouquet; X. H. Zhang

    2011-01-01

    The sintering of two different polycrystalline zinc sulphide powders has been investigated by two different techniques. Conventional sintering technique (Hot Uniaxial Pressing, HUP) and the Spark Plasma Sintering (SPS) also known as electric field-assisted sintering technique (FAST) have been compared in terms of sintering parameters (temperature, pressure) and optical properties of the prepared ZnS ceramics. This study demonstrates the potentiality

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

    SciTech Connect

    Shanthi, N. Theresita [Department of Physics, V. V. College of engineering, Thisaiyanvilai-627 657, Tamilnadu (India); Selvarajan, P. [Department of Physics, Aditanar College of Arts and Science, Tiruchendur-628 216, Tamilnadu (India); Rose, A. S. J. Lucia [Department of Physics, St. Mary's College, Thoothukudi-628 001, Tamilnadu (India)

    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.

  3. Interest of energy dispersive X-ray microanalysis to characterize the surface composition of milk powder particles.

    PubMed

    Murrieta-Pazos, I; Galet, L; Rolland, C; Scher, J; Gaiani, C

    2013-11-01

    Energy dispersive X-ray (EDX) is a technique rarely used for organic powders. Nevertheless, this technique is of great interest in the characterization of milk particle surface. In order to validate the method, the EDX technique was tested on pure milk components, on model powders composed of different ratio of lactose/whey proteins and on whole milk powders presenting or not free fat at the surface. For all these powders, satisfactory results were obtained with correct experimental atomic percentages in comparison with expected theoretical percentages. The technique was then applied to skimmed and whole milk powders sieved in 4 fractions. The surface and the core (cut particle) were analyzed by EDX and compared. A relationship between the particle size and the surface composition was observed. X-ray photoelectron spectroscopy (XPS) often used to characterize milk powder surface, however no differences were observed between surface and core composition using this method. The depth of analysis by EDX is far more significant (1 ?m) in comparison to that of the XPS (5 nm); hence it was concluded that the analysis of cut particle by EDX was not interesting since too close to the results obtained at the surface. Finally, the technique was coupled with XPS and successful hypothesis concerning composition gradients were done. PMID:23831670

  4. Pulsed high energy synthesis of fine metal powders

    NASA Technical Reports Server (NTRS)

    Witherspoon, F. Douglas (Inventor); Massey, Dennis W. (Inventor)

    1999-01-01

    Repetitively pulsed plasma jets generated by a capillary arc discharge at high stagnation pressure (>15,000 psi) and high temperature (>10,000 K) are utilized to produce 0.1-10 .mu.m sized metal powders and decrease cost of production. The plasma jets impact and atomize melt materials to form the fine powders. The melt can originate from a conventional melt stream or from a pulsed arc between two electrodes. Gas streams used in conventional gas atomization are replaced with much higher momentum flux plasma jets. Delivering strong incident shocks aids in primary disintegration of the molten material. A series of short duration, high pressure plasma pulses fragment the molten material. The pulses introduce sharp velocity gradients in the molten material which disintegrates into fine particles. The plasma pulses have peak pressures of approximately one kilobar. The high pressures improve the efficiency of disintegration. High gas flow velocities and pressures are achieved without reduction in gas density. Repetitively pulsed plasma jets will produce powders with lower mean size and narrower size distribution than conventional atomization techniques.

  5. Processing of laser formed SiC powder

    NASA Technical Reports Server (NTRS)

    Haggerty, J. S.; Bowen, H. K.

    1987-01-01

    Processing research was undertaken to demonstrate that superior SiC characteristics could be achieved through the use of ideal constituent powders and careful post-synthesis processing steps. Initial research developed the means to produce approximately 1000 A uniform diameter, nonagglomerated, spherical, high purity SiC powders. Accomplishing this goal required major revision of the particle formation and growth model from one based on classical nucleation and growth to one based on collision and coalescence of Si particles followed by their carburization. Dispersions based on pure organic solvents as well as steric stabilization were investigated. Test parts were made by the colloidal pressing technique; both liquid filtration and consolidation (rearrangement) stages were modeled. Green densities corresponding to a random close packed structure were achieved. After drying, parts were densified at temperatures ranging from 1800 to 2100 C. This research program accomplished all of its major objectives. Superior microstructures and properties were attained by using powders having ideal characteristics and special post-synthesis processing procedures.

  6. Chemical vapor deposition of ruthenium on NiCoCrAlYTa powders followed by thermal oxidation of the sintered coupons

    Microsoft Academic Search

    Fernando Juarez; Daniel Monceau; Daniel Tetard; Bernard Pieraggi; Constantin Vahlas

    2003-01-01

    This paper introduces spouted-bed metal–organic chemical vapor deposition, an original technique for doping by platinum group metals of commercial powders that are used as raw materials in the processing of bond coats in thermal barriers. In this context, Praxair NI-482 NiCoCrAlYTa powders were doped by ruthenium, starting from ruthenocene. The doping level, purity, microstructure and ruthenium distribution of the powders

  7. The effect of citric acid to metal nitrates molar ratio on sol–gel combustion synthesis of nanocrystalline LaMnO 3 powders

    Microsoft Academic Search

    Yuanyuan Li; Lihong Xue; Lingfang Fan; Youwei Yan

    2009-01-01

    Nanocrystalline LaMnO3 powders were synthesized by sol–gel combustion method. The effect of citric acid (CA) to metal nitrates (MN) molar ratio of the precursor solution on the structure of gels and as-synthesized powders, combustion behavior, and microstructure of as-synthesized powders was investigated with the help of thermal analysis, infrared spectra, X-ray diffraction technique and scanning electron microscopy. The results show

  8. Deagglomeration of dry powder pharmaceutical aerosols.

    PubMed

    Voss, Austin; Finlay, Warren H

    2002-11-01

    The effect of turbulence and mechanical impaction on dry powder aerosol deaggregation was tested using a novel powder deagglomeration rig, with fine particle fraction (FPF(ED<5.6 microm)), defined here as particles sized smaller than 5.6 microm, measured using an Anderson inertial impactor. Powder from GlaxoSmithKline Ventodisks was deaggregated either using turbulence generated with a ring of impinging jets, or by impacting the powder on bars of a wire mesh. This deaggregation was compared with deaggregation achieved with the GlaxoSmithKline Diskhaler. The turbulence levels in the test rig and at the exit of the Diskhaler were quantified using laser Doppler velocimetry (LDV). In addition, the Ventodisk powder's auto-adhesion properties were altered by introducing the powder into a high humidity environment (25 degrees C and 25% R.H.) and then deagglomerated by both the rig (using turbulence as the primary deagglomeration mechanism) and the Diskhaler. Fine particle fractions were found to increase from 13 to 24% as the level of turbulence in the rig was increased. However, fine particle fractions found with the Diskhaler were 35%. Turbulence levels found in the rig at the highest jet flow rate were significantly higher than that at the outlet of the Diskhaler, leading to the conclusion that turbulence is not the only method of deaggregation in this inhaler. The humidified powders were significantly more difficult to deaggregate, giving a FPF(ED<5.6 microm) of 9% when using the rig and 15% when using the Diskhaler. Fine particle fractions produced when deagglomerating the powder with the wire meshes were similar to those produced without a mesh, showing that mechanical impaction had little effect. The results underline the utility of having a rig that can explore the ability of a powder to deagglomerate with controlled variations in the deaggregation forces. PMID:12429458

  9. Shock compression response of nanoiron powder compact

    NASA Astrophysics Data System (ADS)

    Dai, Chengda; Eakins, Daniel; Thadhani, Naresh; Liu, J. Ping

    2007-02-01

    The shock compression response of nano-Fe powder (˜25nm) pressed to ˜35% theoretical maximum density was determined based on shock stress and wave velocity measurements using piezoelectric stress gauges. The obtained data show a discontinuity in shock wave velocity plotted against particle velocity and an inflexion in specific volume from compression to expansion with increasing shock stress. It is found that the Hugoniot of 25nm Fe powder cannot be fully described using analytical models that are otherwise capable of predicting the Hugoniot of micron-sized powder or highly porous materials.

  10. Electrical Resistivity of Metal Powder Aggregates

    NASA Astrophysics Data System (ADS)

    Montes, J. M.; Cuevas, F. G.; Cintas, J.

    2007-12-01

    An equation for calculating the electrical resistivity of a compressed powder mass, consisting of oxide-coated metal particles, has been derived. In addition to the intrinsic interest of the problem, the proposed equation is useful for describing the very early stages of electrical sintering processes. The problem is approached in a new way, relating the actual powder system to an equivalent system consisting of deforming spheres in a simple cubic packing, which is much easier to examine. The proposed equation was experimentally verified from measurements of the electrical resistivity for aluminum, bronze, iron, and nickel powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

  11. Microwave heating of conductive powder materials

    NASA Astrophysics Data System (ADS)

    Rybakov, K. I.; Semenov, V. E.; Egorov, S. V.; Eremeev, A. G.; Plotnikov, I. V.; Bykov, Yu. V.

    2006-01-01

    In recent years, a considerable interest has been drawn to microwave heating of powder metals and other electrically conductive materials. In this paper a consistent formulation describing the absorption of microwaves in electrically conductive materials under different microwave heating conditions is developed. A special case when conductive powder particles are surrounded by insulating oxide layers is investigated in detail using the effective-medium approximation. The conditions giving rise to skin effect governed, volumetric, and localized microwave heating are analyzed. Experimental observations of different microwave heating regimes in silicon, iron, and copper powder compacts are in general agreement with the theoretical model.

  12. Pulmonary drug delivery by powder aerosols.

    PubMed

    Yang, Michael Yifei; Chan, John Gar Yan; Chan, Hak-Kim

    2014-11-10

    The efficacy of pharmaceutical aerosols relates to its deposition in the clinically relevant regions of the lungs, which can be assessed by in vivo lung deposition studies. Dry powder formulations are popular as devices are portable and aerosolisation does not require a propellant. Over the years, key advancements in dry powder formulation, device design and our understanding on the mechanics of inhaled pharmaceutical aerosol have opened up new opportunities in treatment of diseases through pulmonary drug delivery. This review covers these advancements and future directions for inhaled dry powder aerosols. PMID:24818765

  13. Analysis of powder diffraction data

    SciTech Connect

    Cooper, M.J.

    1982-01-01

    A comparison has been carried out between the results of analyses of several sets of neutron powder diffraction data using three different methods: the Rietveld method (H.M. Rietveld, Acta. Cryst. 2, 151-152 (1967): J. Appl. Cryst. 2, 65-71 (1969), a modification of the Rietveld method to include off-diagonal terms in the weight matrix (C.P. Clarke and J.S. Rollett, Acta. Cryst. In the press) and the SCRAP method, which involves the estimation of observed Bragg intensities (M.J. Cooper, K.D. Rouse and M. Sakata, Z. Krist. In the press). Two simulations have also been carried out to demonstrate the way in which the results can differ in more extreme cases. This study has confirmed that the values of the estimated standard deviations given by the Rietveld method are not reliable and that, of the methods considered, only the SCRAP method will in general give reliable values for the estimated standard deviations of the structural parameters.

  14. Continuous production of titanium powder

    SciTech Connect

    Gerdemann, Stephen J.; Oden, Laurence L.; White, Jack C.

    1997-01-01

    Although incremental improvements have been made to the Kroll process since its inception in 1948, the process in use today remains essentially the same batch process developed by Dr. Kroll and perfected by the U.S. Bureau of Mines. In this process, titanium tetrachloride (TiCl4) is reduced by magnesium to produce titanium metal. There are two major limitations to the Kroll process: (1) it is a batch process; and (2) the reduction of TiCl4 proceeds so rapidly that the sponge formed is an interlocking dendritic mass with inclusions of magnesium, magnesium salts and titanium subchloride that must undergo several purification steps before the metal is suitable for use. The Albany Research Center (ARC), formerly the U.S. Bureau of Mines, has investigated a new, continuous titanium metal production process in which a titanium powder is produced in a bath of molten salt. In this process, the rate of the reduction reaction was slowed and controlled by diluting the reactants with molten chloride salts. The diluted reactant streams were combined in a continuous stirred tank reactor, operated much like a crystallizer. New titanium metal forms on the already present small Ti particles. When the Ti particles become too large to remain suspended in solution, they fall to the bottom of the reactor and are removed. Initial experiments show promise but problems remain in obtaining the required purity and uniform particle size.

  15. Possibility of making polycrystalline diamond using high-temperature shock consolidation technique

    NASA Astrophysics Data System (ADS)

    Hokamoto, Kazuyuki; Fujita, Masahiro; Tanaka, Sei-ichiro; Ayabe, Makoto; Itoh, Shigeru

    2000-04-01

    High-temperature shock consolidation technique using converging underwater shock wave assembly is employed to compact diamond and its related material powders. Heating the powders gives the effects of softening and melting of powder surfaces, and the samples recovered at 1100 °C shows high hardness which corresponds with the bulk materials to be consolidated.

  16. Effect of boron on polytype phase transformation occurring during sintering of Si-C-B powders obtained by combustion (SHS)

    SciTech Connect

    Gierlotka, S.; Stel`makh, S.; Palosz, B. [Polish Academy of Sciences, Warsaw (Poland). High Pressure Research Centre

    1996-12-31

    Silicon carbide powders were synthesized by SHS method with boron added in various quantities as either amorphous elemental or boric acid additive. The powder samples were then heat treated at a selected temperature (up to 2,200 C). Crystallographic structure of the powders were analyzed by means of X-ray powder diffraction technique. It was found that boron added in the form of H{sub 3}BO{sub 3} tends to precipitate in the form of small clusters and does not dissolve evenly in the SiC lattice. Upon annealing the boron clusters dissociate. The boron atoms diffusing across the SiC lattice generate a large number of stacking faults with simultaneous transformation of hexagonal polytype 6H ({alpha}-phase) present in as-synthesized powders into the cubic 3C ({beta}-phase) modification.

  17. Properties of porous magnesium prepared by powder metallurgy.

    PubMed

    ?apek, Jaroslav; Vojt?ch, Dalibor

    2013-01-01

    Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone. PMID:25428111

  18. Room Temperature Ferromagnetism in Ni Doped ZnO Powders

    Microsoft Academic Search

    Rui Bin Zhao; Deng Lu Hou; Jun Mei Guo; Cong Mian Zhen; Gui De Tang

    2010-01-01

    Zn1?x\\u000a Ni\\u000a x\\u000a O (x=0.1%, 0.4%, 0.7%, 1.0%) powders were prepared using the sol-gel technique, and the structural, optical, and magnetic properties\\u000a of the samples were investigated. X-ray diffraction measurements show that all samples have a wurtzite structure and that\\u000a the c-axis lattice constant decreases as the Ni content increases. X-ray photoelectron spectroscopy studies reveal that the doped\\u000a Ni ions

  19. Nano spray-dried pyrazinamide-l-leucine dry powders, physical properties and feasibility used as dry powder aerosols.

    PubMed

    Kaewjan, Kanogwan; Srichana, Teerapol

    2014-10-21

    Abstract Objective: The aim of this study was to investigate the effect of adding l-leucine and using an ethanolic solvent on the physicochemical properties and aerodynamic behavior of nano spray-dried pyrazinamide (PZA)-l-leucine powders. Materials and methods: A nano spray dryer was employed to prepare PZA-l-leucine powders. The physicochemical properties were evaluated using a scanning electron microscope (SEM), differential scanning calorimetry and X-ray diffraction. The Andersen cascade impactor was used to evaluate the in vitro aerosolization performance of the sprayed powders. Results and discussion: The incorporation of l-leucine at 10% improved the percentage fine particle fraction (%FPF) in all ethanolic solvent formulations by up to nearly twofold (20.0-23.4%) compared to the normal spray-dried PZA of (8.8-13.0%). Changes in the particle density and morphology were also observed. The dense solid particles of PZA were completely converted to bulk hollow particles with a thin shell by increasing the l-leucine content up to 50%. Higher ethanol concentration resulted in larger dimensions of the hollow particle but did not directly affect the aerosolization performance. The co-spray dried PZA with 20% l-leucine in a 10% ethanol feed solvent gave the best aerosolization performance (FPF?=?33.0%). Conclusions: The co-spray dried PZA with a suitable l-leucine content using a nano spray drying technique could be applied to formulate the PZA DPI. PMID:25331092

  20. Optimizing Powder Distribution in Production of Surface Nano-Composite via Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Heydarian, Arash; Dehghani, Kamran; Slamkish, Taymor

    2014-06-01

    Notwithstanding the extensive interest in using friction stir processing (FSP) for producing metal matrix composite (MMC), more uniform powder distribution along the composite zone is still needed. In most studies, one groove is machined out of the specimen, filled with powder, and then processed by identical passes. In this investigation, an innovative technique was used that involved machining out of three gradient grooves with increasing depth from the advancing side to the retreating side instead of using a conventional sample with just a groove. Macro, optical, and scanning electron microscopy (SEM) images and microhardness test were used to evaluate the powder distribution. The images indicated that the most uniform distribution of SiC particles in the whole composite zone was related to a three-gradient grooves sample. Microohardness measurement of a three-gradient grooves sample, carried out along the cross section and perpendicular to the traverse direction of FSP, experiences less fluctuation in hardness compared with other techniques.

  1. Laminated composite of magnetic alloy powder and ceramic powder and process for making same

    DOEpatents

    Moorhead, Arthur J. (Knoxville, TN); Kim, Hyoun-Ee (Seoul, KR)

    1999-01-01

    A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are discosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder.

  2. Effects of milk powders in milk chocolate.

    PubMed

    Liang, B; Hartel, R W

    2004-01-01

    The physical characteristics of milk powders used in chocolate can have significant impact on the processing conditions needed to make that chocolate and the physical and organoleptic properties of the finished product. Four milk powders with different particle characteristics (size, shape, density) and "free" milk fat levels (easily extracted with organic solvent) were evaluated for their effect on the processing conditions and characteristics of chocolates in which they were used. Many aspects of chocolate manufacture and storage (tempering conditions, melt rheology, hardness, bloom stability) were dependent on the level of free milk fat in the milk powder. However, particle characteristics of the milk powder also influenced the physical and sensory properties of the final products. PMID:14765806

  3. Screening and classification of ceramic powders

    NASA Technical Reports Server (NTRS)

    Miwa, S.

    1983-01-01

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

  4. Magnesium Powder Metallurgy: Process and Materials Opportunities

    NASA Astrophysics Data System (ADS)

    Bettles, Colleen J.

    2008-06-01

    The major efforts in magnesium alloy development for automotive applications have concentrated on creep resistant alloys produced by permanent mould and high-pressure die casting routes. While large components, such as crankcases, will never be produced by powder metallurgy, there are smaller components in and around the powertrain which could be fabricated from powder precursors. This article will explore the potential of some of the more recent powder compaction developments, and discuss the alloy development strategies that emerge for magnesium-based components as a consequence of these process developments. In particular, the viability of direct powder extrusion of semi-finished product, using conventional extrusion or equal channel angular processing, combined with T6 heat treatments, will be considered.

  5. Advances in beryllium powder consolidation simulation

    SciTech Connect

    Reardon, B.J.

    1998-12-01

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

  6. The filling of powdered herbs into two-piece hard capsules using hydrogenated cotton seed oil as lubricant.

    PubMed

    Aling, Joanna; Podczeck, Fridrun

    2012-11-20

    The aim of this work was to investigate the plug formation and filling properties of powdered herbal leaves using hydrogenated cotton seed oil as an alternative lubricant. In a first step, unlubricated and lubricated herbal powders were studied on a small scale using a plug simulator, and low-force compression physics and parameterization techniques were used to narrow down the range in which the optimum amount of lubricant required would be found. In a second step these results were complemented with investigations into the flow properties of the powders based on packing (tapping) experiments to establish the final optimum lubricant concentration. Finally, capsule filling of the optimum formulations was undertaken using an instrumented tamp filling machine. This work has shown that hydrogenated cotton seed oil can be used advantageously for the lubrication of herbal leaf powders. Stickiness as observed with magnesium stearate did not occur, and the optimum lubricant concentration was found to be less than that required for magnesium stearate. In this work, lubricant concentrations of 1% or less hydrogenated cotton seed oil were required to fill herbal powders into capsules on the instrumented tamp-filling machine. It was found that in principle all powders could be filled successfully, but that for some powders the use of higher compression settings was disadvantageous. Relationships between the particle size distributions of the powders, their flow and consolidation as well as their filling properties could be identified by multivariate statistical analysis. The work has demonstrated that a combination of the identification of plug formation and powder flow properties is helpful in establishing the optimum lubricant concentration required using a small quantity of powder and a powder plug simulator. On an automated tamp-filling machine, these optimum formulations produced satisfactory capsules in terms of coefficient of fill weight variability and capsule weight. PMID:22960627

  7. Vibrational spectra, powder X-ray diffractions and physical properties of cyanide complexes with 1-ethylimidazole

    NASA Astrophysics Data System (ADS)

    Kürkçüo?lu, Güne? Süheyla; Kiraz, Fulya Çetinkaya; Say?n, Elvan

    2015-10-01

    The heteronuclear tetracyanonickelate(II) complexes of the type [M(etim)Ni(CN)4]n (hereafter, abbreviated as M-Ni-etim, M = Mn(II), Fe(II) or Co(II); etim = 1-ethylimidazole, C5H8N2) were prepared in powder form and characterized by FT-IR and Raman spectroscopy, powder X-ray diffraction (PXRD), thermal (TG; DTG and DTA), and elemental analysis techniques. The structures of these complexes were elucidated using vibrational spectra and powder X-ray diffraction patterns with the peak assignment to provide a better understanding of the structures. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from powder X-ray diffraction measurements. Vibrational spectra of the complexes were presented and discussed with respect to the internal modes of both the etim and the cyanide ligands. The C, H and N analyses were carried out for all the complexes. Thermal behaviors of these complexes were followed using TG, DTG and DTA curves in the temperature range 30-700 °C in the static air atmosphere. The FT-IR, Raman spectra, thermal and powder X-ray analyses revealed no significant differences between the single crystal and powder forms. Additionally, electrical and magnetic properties of the complexes were investigated. The FT-IR and Raman spectroscopy, PXRD, thermal and elemental analyses results propose that these complexes are similar in structure to the Hofmann-type complexes.

  8. Synthesis of ?- and ?-Rhombohedral Boron Powders via Gas Phase Thermal Dissociation of Boron Trichloride by Hydrogen

    NASA Astrophysics Data System (ADS)

    A?ao?ullar?, Duygu; Balc?, Özge; Duman, Ismail; Öveço?lu, M. Lütfi

    2011-06-01

    The ?-rhombohedral and ?-rhombohedral crystal structures of pure elemental boron powders have been synthesized via gas phase thermal dissociation of BCl3 by H2 on a quartz substrate. The parameters affecting the crystal structures of the final products and the process efficiency, such as BCl3/H2 molar ratio (1/2 and 1/4) and reaction temperature (1173 K to 1373 K [900 °C to 1100 °C]), have been examined. The experimental apparatus of original design has enabled boron powders to be obtained at temperatures lower than those in the literature. The surface/powder separation problem encountered previously with different substrate materials has been avoided. Boron powders have been synthesized with a minimum purity of 99.99 pct after repeated HF leaching. The qualitative analysis of exhaust gases has been conducted using a Fourier transform infrared spectroscope (FTIR). The synthesized powders have been characterized using an X-ray powder diffractometer (XRD) and scanning electron microscope (SEM) techniques. The results of the reactions have been compared with equilibrium predictions performed using the FactSage 6.2 (Center for Research in Computational Thermochemistry, Montreal, Canada) thermochemical software.

  9. Laser-induced breakdown spectroscopy measurements of uranium and thorium powders and uranium ore

    NASA Astrophysics Data System (ADS)

    Judge, Elizabeth J.; Barefield, James E., II; Berg, John M.; Clegg, Samuel M.; Havrilla, George J.; Montoya, Velma M.; Le, Loan A.; Lopez, Leon N.

    2013-05-01

    Laser-induced breakdown spectroscopy (LIBS) was used to analyze depleted uranium and thorium oxide powders and uranium ore as a potential rapid in situ analysis technique in nuclear production facilities, environmental sampling, and in-field forensic applications. Material such as pressed pellets and metals, has been extensively studied using LIBS due to the high density of the material and more stable laser-induced plasma formation. Powders, on the other hand, are difficult to analyze using LIBS since ejection and removal of the powder occur in the laser interaction region. The capability of analyzing powders is important in allowing for rapid analysis of suspicious materials, environmental samples, or trace contamination on surfaces since it most closely represents field samples (soil, small particles, debris etc.). The rapid, in situ analysis of samples, including nuclear materials, also reduces costs in sample collection, transportation, sample preparation, and analysis time. Here we demonstrate the detection of actinides in oxide powders and within a uranium ore sample as both pressed pellets and powders on carbon adhesive discs for spectral comparison. The acquired LIBS spectra for both forms of the samples differ in overall intensity but yield a similar distribution of atomic emission spectral lines.

  10. The basics of powder lubrication in high-temperature powder-lubricated dampers

    Microsoft Academic Search

    H. Heshmat; J. F. Walton

    1993-01-01

    The objective of this investigation is to develop a novel powder-lubricated rotor bearing system damper concept for use in high-temperature, high-speed rotating machinery such as advanced aircraft gas turbine engines. The approach discussed herein consists of replacing a conventional oil lubrication or frictional damper system with a powder lubrication system that uses the process particulates or externally fed powder lubricant.

  11. [Use of powder metallurgy for development of implants of Co-Cr-Mo alloy powder].

    PubMed

    Dabrowski, J R

    2001-04-01

    This paper discusses the application of powder metallurgy for the development of porous implantation materials. Powders obtained from Co-Cr-Mo alloy with different carbon content by water spraying and grinding, have been investigated. Cold pressing and rotary re-pressing methods were used for compressing the powder. It was found that the sintered materials obtained from water spraying have the most advantageous properties. PMID:11388037

  12. Research of minimum ignition energy for nano Titanium powder and nano Iron powder

    Microsoft Academic Search

    Hong-Chun Wu; Ri-Cheng Chang; Hsiao-Chi Hsiao

    2009-01-01

    Most manufacturing units that process nanoparticles face a threat from fires and explosions. This study examines Ti powders with diameters of 3?m, 8?m, 20?m, 45?m, 35nm, 75nm, and 100nm, and Fe powders with diameters of 150?m, 15nm, 35nm, and 65nm. The goal of our study was to measure the minimum ignition energy (MIE) for each of the above mentioned powders

  13. Fine PMN powders prepared from nitrate solutions

    Microsoft Academic Search

    Y. Yoshikawa

    1994-01-01

    A partial coprecipitation method was developed in order to synthesize lead magnesium niobate Pb(Mg1\\/3Nb(2\\/3))O3 (PMN) powders from nitrate solutions. To obtain a niobium precursor compatible with the chemical routes, peroxo-niobium complex solutions were prepared by dissolving hydrated niobia precipitates in a dilute nitric acid solution with hydrogen peroxide. Fine PMN powders were prepared from these nitrate solutions by two-stage hydrolysis.

  14. Relative flow rates of explosive powders

    SciTech Connect

    Willson, V.P.

    1988-05-31

    A study was performed to determine the relative flow rates of various explosive powders and evaluate their adaptability for use in automated dispensing systems. Results showed that PBX 9407, LX-15, RX-26-BH, and HNAB are potential candidates for use in these systems. It was also shown that powders with graphite and stearate additives generated the least amount of static and were the easiest to handle.

  15. Synthesis and processing of monosized oxide powders

    DOEpatents

    Barringer, E.A.; Fegley, M.B. Jr.; Bowen, H.K.

    1985-09-24

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 microns can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed. 6 figs.

  16. Synthesis and processing of monosized oxide powders

    DOEpatents

    Barringer, Eric A. (Waltham, MA); Fegley, Jr., M. Bruce (Waban, MA); Bowen, H. Kent (Belmont, MA)

    1985-01-01

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

  17. Electrical Resistivity of Metal Powder Aggregates

    Microsoft Academic Search

    J. M. Montes; F. G. Cuevas; J. Cintas

    2007-01-01

    An equation for calculating the electrical resistivity of a compressed powder mass, consisting of oxide-coated metal particles,\\u000a has been derived. In addition to the intrinsic interest of the problem, the proposed equation is useful for describing the\\u000a very early stages of electrical sintering processes. The problem is approached in a new way, relating the actual powder system\\u000a to an equivalent

  18. Adjustable Powder Injector For Vacuum Plasma Sprayer

    NASA Technical Reports Server (NTRS)

    Burns, D. H.; Woodford, W. H.; Mckechnie, T. N.; Mcferrin, D. C.; Davis, W. M.; Beason, G. P., Jr.

    1993-01-01

    Attachment for plasma spray gun provides four degrees of freedom for adjustment of position and orientation at which powder injected externally into plasma flame. Manipulator provides for adjustment of pitch angle of injection tube: set to inject powder at any angle ranging from perpendicular to parallel to cylindrical axis. Scribed lines on extension bar and manipulator indicate pitch angle of extension tube. Collar changed to adapt injector to different gun.

  19. Dry powder mixes comprising phase change materials

    Microsoft Academic Search

    Salyer; Ival O

    1994-01-01

    Free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used

  20. Dry powder mixes comprising phase change materials

    Microsoft Academic Search

    Salyer; Ival O

    1994-01-01

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be

  1. Dry powder mixes comprising phase change materials

    Microsoft Academic Search

    Salyer; Ival O

    1992-01-01

    Free flowing, conformable powder-like mix of silica particles and a phase change material (p.c.m.) is disclosed. The silica particles have a critical size of about 7.times.10.sup.-3 to about 7.times.10.sup.-2 microns and the pcm must be added to the silica in an amount of 80 wt. % or less pcm per combined weight of silica and pcm. The powder-like mix can

  2. Dry powder mixes comprising phase change materials

    Microsoft Academic Search

    Salyer; Ival O

    1993-01-01

    Free flowing, conformable powder-like mix of silica particles and a phase change material (p.c.m.) is disclosed. The silica particles have a critical size of about 7.times.10.sup.-3 to about 7.times.10.sup.-2 microns and the pcm must be added to the silica in an amount of 80 wt. % or less pcm per combined weight of silica and pcm. The powder-like mix can

  3. Dry powder mixes comprising phase change materials

    Microsoft Academic Search

    Salyer; Ival O

    1995-01-01

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be

  4. Biaxially textured articles formed by powder metallurgy

    DOEpatents

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

    2001-01-01

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

  5. Techniques for fingerprint recovery on vegetable and fruit surfaces used in Slovenia--a preliminary study.

    PubMed

    Trapecar, Matej; Vinkovic, Mojca Kern

    2008-12-01

    An examination was conducted to investigate whether certain dactyloscopic powders and reagents can recover latent fingerprints on vegetable and fruit surfaces (apple, banana, tomato and potato). Two fingerprint powders, Swedish Soot powder mixture (Swedish Black), Silver Special powder and cyanoacrylate fuming (CA), were investigated. The results have shown that detection with Swedish blackpowder is the most suitable procedure as the percentage finger marks which were of adequate quality for further examination, was higher than with any other technique examined. PMID:19192682

  6. Ti Multicomponent Alloy Bulks by Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Zhang, Kuibao; Wen, Guanjun; Dai, Hongchuan; Teng, Yuancheng; Li, Yuxiang

    2014-10-01

    In this study, CrCuFeMnMo0.5Ti multicomponent alloy bulks were prepared by powder metallurgy of mechanical alloying and sintering. A simple body-centered cubic (bcc) solid solution was prepared after 40 h ball milling of the raw CrCuFeMnMo0.5Ti metallic powder. Particles of the alloyed powder are in microsized structures, which are actually a soft agglomeration of lamellar grains with thicknesses less than 1 ?m. Meanwhile, the lamellar granules are consisted of nanosized grains under rigid cold welding. The 80-h ball-milled powder was consolidated by cold pressing and subsequent sintering at 800°C. The observed main phase in the consolidated sample after milling for 80 h is still a bcc solid solution. The solidified sample of 80-h ball-milled powder exhibits a Vickers hardness of 468 HV, which is much higher than 171 HV of the counterpart prepared from the raw metallic powder.

  7. Modelling of the aging behavior of polyamide 12 powder during laser melting process

    NASA Astrophysics Data System (ADS)

    Drummer, Dietmar; Wudy, Katrin; Drexler, Maximilian

    2015-05-01

    Concerning individualization, the requirements to products have increased. Additive manufacturing technologies, such as selective laser melting allow manufacturing of complex parts without tools and forms. Due to this additive manufacturing processes comply, in opposite to conventional techniques, with these increased demands on processing technology. Due to the high temperature during processing, a degradation of the used plastic powder occurs. The non-molten material in the building chamber, the so-called partcake, can be removed after building from the finished component and reused for another process. To realize reproducible part properties refreshing of partcake powder with 30 up to 50 % virgin powder is necessary. However, these refreshing strategies lead to varying component properties due to an undefined aging state. Previous investigations on oven aged powder for selective laser melting showed for short periods of storage near the melting point thermally induced post condensation is the predominate aging effect. Due to post condensation the molecular weight and thus the viscosity increases. This paper focuses on the modeling of the post condensation process to define the aging state of polyamide 12 powder in laser melting process. Therefore the rheological behavior of PA 12 powder in dependency of time and temperature is investigated. Isothermal viscosity measurements are conducted in order to describe the post condensation reaction with a model. With knowledge of the kinetics of the post condensation reaction the state of aging can be predicted in a second step. Thus expected useful life of the powder can be calculated in dependency of the building chamber temperature. These results are then compared with viscosity values of defined aged PA 12 powder to validate the determined model.

  8. Powder diffraction studies using anomalous dispersion

    SciTech Connect

    Cox, D.E. (Brookhaven National Lab., Upton, NY (United States)); Wilkinson, A.P. (California Univ., Santa Barbara, CA (United States). Dept. of Materials)

    1993-01-01

    With the increasing availability and accessibility of high resolution powder diffractometers at many synchrotron radiation sources throughout the world, there is rapidly-growing interest in the exploitation of anomalous dispersion techniques for structural studies of polycrystalline materials. In conjunction with the Rietveld profile method for structure refinement, such studies are especially useful for the determination of the site distributions of two or more atoms which are near neighbors in the periodic table, or atoms which are distributed among partially occupied sites. Additionally, it is possible to (1) determine the mean-square displacements associated with different kinds of atoms distributed over a single set of sites, (2) distinguish between different oxidation states and coordination geometries of a particular atom in a compound and (3) to determine f' for a wide range of atomic species as a function of energy in the vicinity of an absorption edge. Experimental methods for making anomalous dispersion measurements are described in some detail, including data collection strategies, data analysis and correlation problems, possible systematic errors, and the accuracy of the results. Recent work in the field is reviewed, including cation site-distribution studies (e.g. doped high [Tc] superconductors, ternary alloys, FeCo[sub 2](PO[sub 4])[sub 3], FeNi[sub 2]BO[sub 5]), oxidation-state contrast (e.g. YBa[sub 2]Cu[sub 3]O[sub 6+x], Eu[sub 3]O[sub 4], GaCl[sub 2], Fe[sub 2]PO[sub 5]), and the effect of coordination geometry (e.g. Y[sub 3]Ga[sub 5]O[sub l2]).

  9. Powder diffraction studies using anomalous dispersion

    SciTech Connect

    Cox, D.E. [Brookhaven National Lab., Upton, NY (United States); Wilkinson, A.P. [California Univ., Santa Barbara, CA (United States). Dept. of Materials

    1993-05-01

    With the increasing availability and accessibility of high resolution powder diffractometers at many synchrotron radiation sources throughout the world, there is rapidly-growing interest in the exploitation of anomalous dispersion techniques for structural studies of polycrystalline materials. In conjunction with the Rietveld profile method for structure refinement, such studies are especially useful for the determination of the site distributions of two or more atoms which are near neighbors in the periodic table, or atoms which are distributed among partially occupied sites. Additionally, it is possible to (1) determine the mean-square displacements associated with different kinds of atoms distributed over a single set of sites, (2) distinguish between different oxidation states and coordination geometries of a particular atom in a compound and (3) to determine f` for a wide range of atomic species as a function of energy in the vicinity of an absorption edge. Experimental methods for making anomalous dispersion measurements are described in some detail, including data collection strategies, data analysis and correlation problems, possible systematic errors, and the accuracy of the results. Recent work in the field is reviewed, including cation site-distribution studies (e.g. doped high {Tc} superconductors, ternary alloys, FeCo{sub 2}(PO{sub 4}){sub 3}, FeNi{sub 2}BO{sub 5}), oxidation-state contrast (e.g. YBa{sub 2}Cu{sub 3}O{sub 6+x}, Eu{sub 3}O{sub 4}, GaCl{sub 2}, Fe{sub 2}PO{sub 5}), and the effect of coordination geometry (e.g. Y{sub 3}Ga{sub 5}O{sub l2}).

  10. The application of PLC in electrostatic powder sprayer

    Microsoft Academic Search

    Caiqiao Wei; Tianyan Ma; Deping Zhang

    2011-01-01

    In order to prevent the glass from scratching and mildewing in storage and transportation, the anti-mildew powder should be added between the glass. For the demand of the powder spraying , the electrostatic powder sprayer control system based on PLC was developed. Spraying constant powder for the middle -part glass of variable thickness realized by controlling two frequency converters respectively.

  11. Dispersion of alkoxide-hydrolysed zirconia powders in aqueous suspensions

    Microsoft Academic Search

    Kwang-Lung Lin; Huey-Chang Wang

    1989-01-01

    It is always desirable to control the agglomeration of ceramic powders in ceramic processing, as this strongly affects the sintering behaviour [1, 2] of the powders. A recent wet chemical process deserves attention because of the possibility of achieving ultrafine, high-purity monodispersed ceramic powders [3, 4] and the possibility of the powders obtained to yield ultrastructure [5]. During wet chemical

  12. Modelling Dry Powder Inhaler Operation with the Discrete Element

    E-print Network

    Frey, Pascal

    Modelling Dry Powder Inhaler Operation with the Discrete Element Method Robert James Tuley Powder Inhaler Operation with the Discrete Element Method Robert James Tuley Abstract Dry powder inhalers is known about their internal operation: the process of fluidising a powder dose into an inhalation airflow

  13. Lining of light metals with hard powders using shot peening

    Microsoft Academic Search

    Yasunori Harada; Ken-ichiro Mori; Seijiro Maki

    2002-01-01

    A lining of light metals with hard powders using shot peening was carried out. The hard powders are bonded to the surface of the workpieces due to the collision with many shots. To fix the hard powders on the surface of the workpiece, the powder is placed on the uneven surface, and the surface is covered with a pure aluminium

  14. January 2013 BEE CULTURE 23 Revisiting Powdered Sugar For

    E-print Network

    Delaplane, Keith S.

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

  15. Hemostatic powder spray: a new method for managing gastrointestinal bleeding.

    PubMed

    Changela, Kinesh; Papafragkakis, Haris; Ofori, Emmanuel; Ona, Mel A; Krishnaiah, Mahesh; Duddempudi, Sushil; Anand, Sury

    2015-05-01

    Gastrointestinal bleeding is a leading cause of morbidity and mortality in the United States. The management of gastrointestinal bleeding is often challenging, depending on its location and severity. To date, widely accepted hemostatic treatment options include injection of epinephrine and tissue adhesives such as cyanoacrylate, ablative therapy with contact modalities such as thermal coagulation with heater probe and bipolar hemostatic forceps, noncontact modalities such as photodynamic therapy and argon plasma coagulation, and mechanical hemostasis with band ligation, endoscopic hemoclips, and over-the-scope clips. These approaches, albeit effective in achieving hemostasis, are associated with a 5-10% rebleeding risk. New simple, effective, universal, and safe methods are needed to address some of the challenges posed by the current endoscopic hemostatic techniques. The use of a novel hemostatic powder spray appears to be effective and safe in controlling upper and lower gastrointestinal bleeding. Although initial reports of hemostatic powder spray as an innovative approach to manage gastrointestinal bleeding are promising, further studies are needed to support and confirm its efficacy and safety. The aim of this study was to evaluate the technical feasibility, clinical efficacy, and safety of hemostatic powder spray (Hemospray, Cook Medical, Winston-Salem, North Carolina, USA) as a new method for managing gastrointestinal bleeding. In this review article, we performed an extensive literature search summarizing case reports and case series of Hemospray for the management of gastrointestinal bleeding. Indications, features, technique, deployment, success rate, complications, and limitations are discussed. The combined technical and clinical success rate of Hemospray was 88.5% (207/234) among the human subjects and 81.8% (9/11) among the porcine models studied. Rebleeding occurred within 72 hours post-treatment in 38 patients (38/234; 16.2%) and in three porcine models (3/11; 27.3%). No procedure-related adverse events were associated with the use of Hemospray. Hemospray appears to be a safe and effective approach in the management of gastrointestinal bleeding. PMID:26082803

  16. Hemostatic powder spray: a new method for managing gastrointestinal bleeding

    PubMed Central

    Papafragkakis, Haris; Ofori, Emmanuel; Ona, Mel A.; Krishnaiah, Mahesh; Duddempudi, Sushil; Anand, Sury

    2015-01-01

    Gastrointestinal bleeding is a leading cause of morbidity and mortality in the United States. The management of gastrointestinal bleeding is often challenging, depending on its location and severity. To date, widely accepted hemostatic treatment options include injection of epinephrine and tissue adhesives such as cyanoacrylate, ablative therapy with contact modalities such as thermal coagulation with heater probe and bipolar hemostatic forceps, noncontact modalities such as photodynamic therapy and argon plasma coagulation, and mechanical hemostasis with band ligation, endoscopic hemoclips, and over-the-scope clips. These approaches, albeit effective in achieving hemostasis, are associated with a 5–10% rebleeding risk. New simple, effective, universal, and safe methods are needed to address some of the challenges posed by the current endoscopic hemostatic techniques. The use of a novel hemostatic powder spray appears to be effective and safe in controlling upper and lower gastrointestinal bleeding. Although initial reports of hemostatic powder spray as an innovative approach to manage gastrointestinal bleeding are promising, further studies are needed to support and confirm its efficacy and safety. The aim of this study was to evaluate the technical feasibility, clinical efficacy, and safety of hemostatic powder spray (Hemospray, Cook Medical, Winston-Salem, North Carolina, USA) as a new method for managing gastrointestinal bleeding. In this review article, we performed an extensive literature search summarizing case reports and case series of Hemospray for the management of gastrointestinal bleeding. Indications, features, technique, deployment, success rate, complications, and limitations are discussed. The combined technical and clinical success rate of Hemospray was 88.5% (207/234) among the human subjects and 81.8% (9/11) among the porcine models studied. Rebleeding occurred within 72 hours post-treatment in 38 patients (38/234; 16.2%) and in three porcine models (3/11; 27.3%). No procedure-related adverse events were associated with the use of Hemospray. Hemospray appears to be a safe and effective approach in the management of gastrointestinal bleeding. PMID:26082803

  17. Materials processing research opportunities in powder injection molding

    SciTech Connect

    German, R.M. [Penn State Univ., University Park, PA (United States)

    1995-12-31

    Materials processing is an active area with many research opportunities for advanced instrumentation, control, and modeling. Among new materials processing routes, powder injection molding (PIM) has rapidly grown from a curiosity to a viable production technique over just a few years. This manufacturing technique is applicable to all materials, and is the preferred fabrication route for many complex-shaped, high-performance components for surgical tools, computer hardware, automotive systems, consumer products, and turbine components. This presentation introduces the use of a computer controlled injection molding machine to shape powders (metal, carbide, composite, and ceramic) in a high productivity setting. After molding the organic is extracted and the powder structure is sintered to full density. Much research is needed in process modeling, control, inspection, and optimization. This presentation summarizes the basic technology and several important factors relevant to manufacturing. An important development is in minimization of molding defects via closed-loop feedback control using pressure, temperature, and optical sensors. Recent progress has occurred using in situ guided waves for ultrasonic inspection of the molded part. Neural networks are being generated to allow assessment of processing changes as required from the integrated robot, visual imaging, pressure, and ultrasonic sensors. Similar, but less refined efforts are occurring in die compaction technology. As another example, computer simulation of heat transfer is needed during sintering to understand sources of component warpage during densification. A furnace equipped with visual imaging and residual gas analysis is being used to assist in verification of such computer simulations. These tools are still in the research stage, so future integration into the manufacturing environment will bring new challenges.

  18. A review on powder-based additive manufacturing for tissue engineering: selective laser sintering and inkjet 3D printing

    NASA Astrophysics Data System (ADS)

    Farid Seyed Shirazi, Seyed; Gharehkhani, Samira; Mehrali, Mehdi; Yarmand, Hooman; Metselaar, Hendrik Simon Cornelis; Adib Kadri, Nahrizul; Azuan Abu Osman, Noor

    2015-06-01

    Since most starting materials for tissue engineering are in powder form, using powder-based additive manufacturing methods is attractive and practical. The principal point of employing additive manufacturing (AM) systems is to fabricate parts with arbitrary geometrical complexity with relatively minimal tooling cost and time. Selective laser sintering (SLS) and inkjet 3D printing (3DP) are two powerful and versatile AM techniques which are applicable to powder-based material systems. Hence, the latest state of knowledge available on the use of AM powder-based techniques in tissue engineering and their effect on mechanical and biological properties of fabricated tissues and scaffolds must be updated. Determining the effective setup of parameters, developing improved biocompatible/bioactive materials, and improving the mechanical/biological properties of laser sintered and 3D printed tissues are the three main concerns which have been investigated in this article.

  19. Application of powder metallurgy to an advanced-temperature nickel-base alloy, NASA-TRW 6-A

    NASA Technical Reports Server (NTRS)

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

    1971-01-01

    Bar stock of the NASA-TRW 6-A alloy was made by prealloyed powder techniques and its properties evaluated over a range of temperatures. Room temperature ultimate tensile strength was 1894 MN/sq m (274 500 psi). The as-extruded powder product showed substantial improvements in strength over the cast alloy up to 649 C (1200 F) and superplasticity at 1093 C (2000 F). Both conventional and autoclave heat treatments were applied to the extruded powder product. The conventional heat treatment was effective in increasing rupture life at 649 and 704 C (1200 and 1300 F); the autoclave heat treatment, at 760 and 816 C (1400 and 1500 F).

  20. Mixed amorphous and nanocrystalline TiO 2 powders prepared by sol–gel method: Characterization and photocatalytic study

    Microsoft Academic Search

    Miki Kanna; Sumpun Wongnawa

    2008-01-01

    Mixed titanium dioxide (TiO2) powders of various amorphous-anatase–rutile contents were prepared by acid-catalyzed sol–gel method at 80°C without calcination. The physico-chemical properties of the powders were investigated by powder XRD, SEM, Brunauer–Emmett–Teller (BET), Fourier-transformed infrared (FT-IR), X-ray energy-dispersive (EDX), and UV–vis techniques. The results showed that the products were mixtures of mainly amorphous TiO2 with small amount of anatase and

  1. Consolidation phenomena in laser and powder-bed based layered manufacturing

    Microsoft Academic Search

    J.-P. Kruth; G. Levy; F. Klocke; T. H. C. Childs

    2007-01-01

    Layered manufacturing (LM) is gaining ground for manufacturing prototypes (RP), tools (RT) and functional end products (RM). Laser and powder bed based manufacturing (i.e. selective laser sintering\\/melting or its variants) holds a special place within the variety of LM processes: no other LM techniques allow processing polymers, metals, ceramics as well as many types of composites. To do so, however,

  2. Influence of coating recycled aggregate surface with pozzolanic powder on properties of recycled aggregate concrete

    Microsoft Academic Search

    Jiusu Li; Hanning Xiao; Yong Zhou

    2009-01-01

    A two-stage crushing process was utilized to produce recycled aggregate (RA). The slump of concrete mixes prepared by technique of stone enveloped with pozzolanic powder (SEPP) was compared with those using normal mixing approach (NMA) or stone enveloped with portland cement (SEPC) approach. After 7 and 28 days curing, the compressive and flexural strengths were tested. The slump and strength

  3. The use of dry powder inhaler devices by elderly patients suffering from chronic obstructive pulmonary disease

    Microsoft Academic Search

    P. Quinet; C. A. Young; F. Héritier

    2010-01-01

    Twenty-five COPD patients, aged 65years or above, were recruited to test their ability to use dry powder inhaler Handihaler® (Boeringher-Ingelheim) and Aerolizer® (Novartis). The results of a score created to evaluate the inhalation technique were compared with age, MMSE, Barthel Index, FEV1, maximum inspiratory and expiratory pressures, and peak inspiratory flow (PIF).

  4. Pollution control of surface waters by coupling gliding discharge treatment with incorporated oyster shell powder

    Microsoft Academic Search

    E. Njoyim-Tamungang; S. Laminsi; P. Ghogomu; D. Njopwouo; J.-L. Brisset

    2011-01-01

    Highly oxidizing gaseous species (OH, NO and derivatives) formed in an electrical discharge (a gliding discharge burning in humid air), are suitable for abating the organic pollutant concentration of surface waters sampled in Cameroonian brooks, e.g., 47% (Total Organic Carbon, TOC) within 10min exposure. The plasma technique coupled with the use of finely powdered oyster shell (OS) acting as a

  5. Chemical Synthesis of Pure and Gd-doped CaZrO3 Powders

    E-print Network

    Tas, A. Cuneyt

    chemical synthesis techniques: (i) self-propagating combustion synthesis, and (ii) precipitation potential use as a high-temperature thermistor material.8 The electrical response of calcium zirconate (preChemical Synthesis of Pure and Gd-doped CaZrO3 Powders I. Erkin Gonenli a and A. CuÈ neyt Tas b

  6. GRADIENT INDEX SPHERES BY THE SEQUENTIAL ACCRETION OF GLASS POWDERS

    SciTech Connect

    MARIANO VELEZ

    2008-06-15

    The Department of Energy is seeking a method for fabricating mm-scale spheres having a refractive index that varies smoothly and continuously from the center to its surface [1]. The fabrication procedure must allow the creation of a range of index profiles. The spheres are to be optically transparent and have a refractive index differential greater than 0.2. The sphere materials can be either organic or inorganic and the fabrication technique must be capable of scaling to low cost production. Mo-Sci Corporation proposed to develop optical quality gradient refractive index (GRIN) glass spheres of millimeter scale (1 to 2 mm diameter) by the sequential accretion and consolidation of glass powders. Other techniques were also tested to make GRIN spheres as the powder-accretion method produced non-concentric layers and poor optical quality glass spheres. Potential ways to make the GRIN spheres were (1) by "coating" glass spheres (1 to 2 mm diameter) with molten glass in a two step process; and (2) by coating glass spheres with polymer layers.

  7. Water Outgassing from PBX-9502 powder by isoconversional thermal analysis

    SciTech Connect

    Dinh, L N; Glascoe, E L; Small, W

    2009-01-12

    Temperature programmed desorption/decomposition (TPD) were performed on PBX-9502 after 3 hours of vacuum pump. TPD data were analyzed by the technique of isoconversional analysis to obtain outgassing kinetics and moisture content of PBX-9502 powder as well as to construct water outgassing models for PBX-9502 powder as a function of time and temperature. Following 3 hours of vacuum pump, dry storage of PBX-9502 at 300K, quickly gives rise to 180-330 ppm moisture in the first few years. Thereafter, the moisture outgassing continues at a much slower rate, totaling only to {approx} 210-380 ppm after 100 years of storage. In an effort to understand the nature of the moisture outgassing in PBX-9502, we have measured moisture content and outgassing kinetics in PBX-9502 by the experimental technique of TPD and the isoconversional thermal analysis. The results of these measurements were then used to construct moisture outgassing models for PBX-9502 in a dry environment (following 3 hours of vacuum pump).

  8. Application of ANN in the prediction of the pore concentration of aluminum metal foams manufactured by powder metallurgy methods

    Microsoft Academic Search

    Sermin Ozan; Mustafa Taskin; Sedat Kolukisa; Mehmet Sirac Ozerdem

    2008-01-01

    In this work, the effect of fabrication parameters on the pore concentration of aluminum metal foam, manufactured by the powder\\u000a metallurgy process, has been studied. The artificial neural network (ANN) technique has been used to predict pore concentration\\u000a as a function of some key fabrication parameters. Aluminum metal foam specimens were fabricated from a mixture of aluminum\\u000a powders (mean particle

  9. Thermal analysis of self-propagating high-temperature reactions in titanium, boron, and aluminum powder compacts

    Microsoft Academic Search

    L. H. Chiu; D. C. Nagle; L. A. Bonney

    1999-01-01

    This article focuses on the characterization of self-propagating high-temperature synthesis (SHS) reactions that occur in\\u000a powder compacts containing titanium, boron, and aluminum. Interest in this powder system is based on the critical need to\\u000a develop new joining techniques for bonding ceramics to metals. The exothermic reactions of particular interest in this study\\u000a include those that generate TiB2, TiB, Ti3Al, and

  10. Facile Synthesis of Lead-Free Piezoelectric Sodium Niobate (NaNbO3) Powders via the Solution Combustion Method

    Microsoft Academic Search

    Nopsiri Chaiyo; Anucha Ruangphanit; Banjong Boonchom; Naratip Vittayakorn

    2011-01-01

    Nanocrystalline perovskite sodium niobate, NaNbO3 (NN), was prepared by means of the glycine-nitrate combustion process (GNP). This was achieved by using sodium nitrate and niobium pentoxide as starting materials. The X-ray diffraction technique (XRD) was used to investigate the phase formation and purity of synthesized powder. The morphology of the powder obtained was characterized using a scanning electron microscope (SEM).

  11. Preparation of pure perovskite-type BaSnO 3 powders by the polymerized complex method at reduced temperature

    Microsoft Academic Search

    Chandana Premakumara Udawatte; Masato Kakihana; Masahiro Yoshimura

    1998-01-01

    Cubic perovskite-type pure barium stannate, BaSnO3, powders were prepared using the polymerized complex technique at the relatively low temperature of 600°C. SnCl4·xH2O was first dissolved in ethylene glycol (EG) and anhydrous citric acid (CA) was then added. After complete dissolution, BaCO3 powder was added and the mixture was stirred at 80°C for several hours until the solution became transparent, demonstrating

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

    DOEpatents

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

    2011-04-12

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

  13. Thermal, mechanical, electrical, linear and nonlinear optical properties of L-arginine dihydrofluoride single crystal

    NASA Astrophysics Data System (ADS)

    Sankar, D.; Menon, Vinay Raj; Sagayaraj, P.; Madhavan, J.

    2010-01-01

    L-arginine dihydrofluoride of dimensions upto 15×10×9 mm 3 was successfully grown by slow evaporation technique from aqueous solution. The crystal was characterized by X-ray diffractometry, Elemental analysis, FT-IR, UV-Vis-NIR spectroscopy, thermal and microhardness studies. The dielectric constant and dielectric loss of the crystal were studied as function of frequency. Photoconductivity studies were also carried out on the sample. Kurtz powder SHG measurement confirms the NLO property of the grown crystals.

  14. Simulation of powder metal fabrication with high pressure gas atomization

    SciTech Connect

    Kuntz, D.W.; Payne, J.L.

    1994-12-31

    A computational/analytical technique has been developed which models the physics of high pressure gas atomization. The technique uses an uncoupled approach, such that the gas flowfield is initially calculated with a commercially-available Navier-Stokes code. The liquid metal droplet breakup, dynamics, and thermodynamics, are then calculated using the pre-computed flowfield by a separate computer program written by the authors. The atomization code models the primary breakup of the liquid metal stream, tracks the droplets resulting from primary breakup through the flowfield until they undergo secondary breakup, and then tracks the subdroplets until they breakup, solidify, or leave the flowfield region of interest. The statistical properties of the metal powder produced are then computed from the characteristics of these droplets. Comparisons between experimental measurements and computations indicate that the Navier-Stokes code is predicting the gas flowfield well, and that the atomization code is properly modeling the physics of the droplet dynamics and breakup.

  15. Reduction and carburization in iron powder production at the brovary powder metallurgy factory

    Microsoft Academic Search

    A. F. Zhornyak; Yu. I. Timchenko; I. M. Fedorenko

    1968-01-01

    1.Study of the reduction and carburization kinetics in iron powder furnaces exposed and led to the removal of several shortcomings in these units.2.A method has been developed for reducing the charge in porous drip pans made from rolled powders. Trials using this method showed that the porous drip pans improve heat transfer and gas permeability of the charge and so

  16. Drop penetration into porous powder beds.

    PubMed

    Hapgood, Karen P; Litster, James D; Biggs, Simon R; Howes, Tony

    2002-09-15

    The kinetics of drop penetration were studied by filming single drops of several different fluids (water, PEG200, PEG600, and HPC solutions) as they penetrated into loosely packed beds of glass ballotini, lactose, zinc oxide, and titanium dioxide powders. Measured times ranged from 0.45 to 126 s and depended on the powder particle size, viscosity, surface tensions, and contact angle. The experimental drop penetration times were compared to existing theoretical predictions by M. Denesuk et al. (J. Colloid Interface Sci.158, 114, 1993) and S. Middleman ("Modeling Axisymmetric Flows: Dynamics of Films, Jets, and Drops," Academic Press, San Diego, 1995) but did not agree. Loosely packed powder beds tend to have a heterogeneous bed structure containing large macrovoids which do not participate in liquid flow but are included implicitly in the existing approach to estimating powder pore size. A new two-phase model was proposed where the total volume of the macrovoids was assumed to be the difference between the bed porosity and the tap porosity. A new parameter, the effective porosity epsilon(eff), was defined as the tap porosity multiplied by the fraction of pores that terminate at a macrovoid and are effectively blocked pores. The improved drop penetration model was much more successful at estimating the drop penetration time on all powders and the predicted times were generally within an order of magnitude of the experimental results. PMID:16290866

  17. The effect of temperature dependences on optical properties of PMN-PZT nano-powders

    Microsoft Academic Search

    Mahdi Ghasemifard; Matineh Zavar; Hadi Ghasemifard; Hossein Asghar Rahnamaye Aliabad

    2010-01-01

    PMN-PZT nano-powders were prepared by citrate-nitrate gel-combustion technique and optical parameters were obtained by Kramers-Kronig\\u000a transformation. Organic metals and metal salts precursor were employed in this process. X-ray diffraction shows that increasing\\u000a the temperature from 500°C to 800°C reduces the pyrochlore unwanted phase in nano-powders so that in 900°C the single phase\\u000a of perovskite formed. According to the TEM images,

  18. Structure and ferromagnetic properties of Co-doped ZnO powders

    Microsoft Academic Search

    Xingyan Xu; Chuanbao Cao

    2009-01-01

    Single-phase Zn1?xCoxO (x=0.02, 0.04) powders were synthesized by a simple co-precipitation technique. X-ray diffraction analysis reveals that the Co-doped ZnO crystallizes in a wurtzite structure. The lattice constants of Co-doped ZnO powders decrease slightly when Co is doped into ZnO. Optical absorption spectra show a decrease in the bandgap with increasing Co content and also give an evidence of the

  19. Structural investigation of Lisinopril by powder X-ray diffraction and solid-state NMR

    NASA Astrophysics Data System (ADS)

    Filip, Xenia; Tripon, Carmen; Borodi, Gheorghe; Oprean, Lumini?a; Filip, Claudiu

    2009-08-01

    Structural studies on polycrystalline Lisinopril (N-N-[(s)-1-carboxy-3-phenylpropyl]-L-lysil-L-proline) are performed by combined powder X-Ray diffraction and 13C solid-state nuclear magnetic resonance (NMR). The crystal structure of this drug, used primarily for the treatment of hypertension, has not yet been determined due to the impossibility of synthesizing single crystals of sufficient quality. It is shown here that valuable insights into the crystal and molecular structure of Lisinopril can be obtained on polycrystalline powder based on the complementary character of the information provided by the two techniques.

  20. Nanoparticle size distribution estimation by a full-pattern powder diffraction analysis

    SciTech Connect

    Cervellino, A.; Giannini, C.; Guagliardi, A.; Ladisa, M. [Laboratory for Neutron Scattering, PSI Villigen and ETH Zurich, CH-5232 Villigen PSI (Switzerland); Consiglio Nazionale delle Ricerche, Istituto di Cristallografia (CNR-IC), Via Amendola 122/O, I-70126 Bari (Italy)

    2005-07-15

    The increasing scientific and technological interest in nanoparticles has raised the need for fast, efficient, and precise characterization techniques. Powder diffraction is a very efficient experimental method, as it is straightforward and nondestructive. However, its use for extracting information regarding very small particles brings some common crystallographic approximations to and beyond their limits of validity. Powder pattern diffraction calculation methods are critically discussed, with special focus on spherical particles with log-normal distributions, with the target of determining size distribution parameters. A 20-nm CeO{sub 2} sample is analyzed as an example.

  1. Innovative processing techniques for intermetallic matrix composites

    NASA Astrophysics Data System (ADS)

    Stoloff, N. S.; Alman, D. E.

    A wide range of innovative techniques for processing intermetallic matrix composites is surveyed. The majority of processes involve the use of powders, although increasing attention is being directed towards vapor phase techniques. Most intermetallic composites produced to date are reinforced by particulates or random fibers. Several techniques have been successfully employed to produce continuous fiber reinforcements. Injection molding is feasible for producing aligned short fiber reinforced composites. The major success of the various new processing techniques is improved strength (monotonic and creep).

  2. Growth and characterization of NLO based L-arginine maleate dihydrate single crystal

    NASA Astrophysics Data System (ADS)

    Baraniraj, T.; Philominathan, P.

    2010-01-01

    Single crystals of L-arginine maleate dihydrate (LAMD) were successfully grown from aqueous solution by solvent evaporation technique. As-grown crystals were analyzed by different instrumentation techniques such as X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectra and UV-vis near infrared (NIR) transmittance spectra. Thermal behavior has been studied with TGA/DTA analyses. The optical second harmonic generation (SHG) conversion efficiency of LAMD was determined using Kurtz powder technique and found to be 1.5 times that of KDP.

  3. A hydroxycarbonate route to superconductor precursor powders

    SciTech Connect

    Voigt, J.A.; Bunker, B.C.; Doughty, D.H.; Lamppa, D.L.; Kimball, K.M.

    1987-01-01

    A precipitation process is described for the preparation of powders that can be thermally decomposed to form high critical temperature superconductors such as YBa/sub 2/Cu/sub 3/O/sub 7/. In the process, a cationic solution (a concentrated chloride or nitrate solution) is instantaneously mixed with an anionic solution (a mixture of tetramethylammonium hydroxide and carbonate) to produce a metal-hydroxycarbonate precipitate having the metal stoichiometry of the desired superconducting oxide. The calcining and sintering of the precipitates is critical in controlling the structural integrity and morphology of the superconducting cermaics made from the chem-prep powders, as well as controlling superconducting properties. Under appropriate conditions, high density (>95%) materials that exhibit good superconducting characteristics can be prepared with the chem-prep powders. 6 refs., 3 figs.

  4. Nitridation of chromium powder in ammonia atmosphere

    NASA Astrophysics Data System (ADS)

    Li, Ling; Zhen, Qiang; Li, Rong

    2015-03-01

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

  5. Biaxially textured articles formed by powder metallurgy

    DOEpatents

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

    2003-10-21

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

  6. [Dry powder inhalers in cystic fibrosis].

    PubMed

    Steinkamp, G

    2014-06-01

    Inhaled medications play an important role in the daily treatment of patients with cystic fibrosis (CF). The classic route of administration was nebulisation via jet nebulisers. Respiratory delivery of fluid particles should loosen the viscid respiratory secretions, making airway clearance via cough or physiotherapy more efficient. Until recently, only jet nebulisers allowed to administer high doses of aerosolised antipseudomonal antibiotics. Powder inhalers for the treatment of cystic fibrosis have recently been made available. The newly developed powders and inhalers differ considerably from conventional dry powder inhalers used for the treatment of chronic obstructive airway disease. The present article will review two inhaled antibiotics, i.?e. tobramycin and colistin, and the hyperosmotic agent mannitol, which increases the hydration of the airways. Topics are particle engineering, efficacy and tolerability results from clinical trials, as well as functional and practical aspects related to these new drugs. PMID:24664997

  7. Atomization methods for forming magnet powders

    DOEpatents

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

    2000-01-01

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

  8. Synthesis of ultrafine powders by microwave heating

    DOEpatents

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

    1987-04-24

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

  9. Removing Undesired Fine Powder From Silicon Reactor

    NASA Technical Reports Server (NTRS)

    Flagella, Robert N.

    1992-01-01

    Fluidized-bed reactor produces highly pure polycrystalline silicon particles with diameters approximately greater than 400 micrometers. Operates by pyrolysis of silane in reaction zone, which is bed of silicon seed particles fluidized by flow of silane and carrier gas. Above reaction zone, gas mixture flows rapidly enough to entrain silicon powders, but not larger seed and product particles. Entrained particles swept out of reactor. Applicable to other processes such as production of fine metal and ceramic powders where control of sizes of product needed.

  10. Alternative carriers in dry powder inhaler formulations.

    PubMed

    Rahimpour, Yahya; Kouhsoltani, Maryam; Hamishehkar, Hamed

    2014-05-01

    The aerosolization efficiency of a powder is highly dependent on carrier characteristics, such as particle size distribution, shape and surface properties. The main objective in the inhalation field is to achieve a high and reproducible pulmonary deposition. This can be provided by successful carrier selection and careful process optimization for carrier modification. Lactose is the most common and frequently used carrier in dry powder inhaler (DPI) formulations. But lactose shows some limitations in formulation with certain drugs and peptides that prohibit its usage as a carrier in DPI formulations. Here, we criticality review the most important alternative carriers to lactose with merits, demerits and applications in DPI formulations. PMID:24269834

  11. Thermal Oxidation of Aluminum Nitride Powder

    SciTech Connect

    Gu, Zheng; Edgar, James H.; Wang, Chong M.; Coffey, Dorothy

    2006-07-31

    The kinetics of the thermal oxidation of AlN powder in flowing oxygen over temperatures from 800 to 1150 C and the morphology and crystallinity of the resultant oxide were determined. The oxidation of two types of AlN powder was investigated and compared. Complex difference in the oxidation behavior was observed, probably due to their different morphology, particle size, particle size distribution, and residual impurities. Amorphous alumina formed at relatively low oxidation temperatures (800-1000 C), with a linear oxidation rate governed by interfacial reaction. Crystalline alumina formed at higher temperatures (>1000 C), and the oxidation rate was parabolic which suggested an oxidant diffusion controlled process.

  12. Random Laser Action in Semiconductor Powder

    NASA Astrophysics Data System (ADS)

    Cao, H.; Zhao, Y. G.; Ho, S. T.; Seelig, E. W.; Wang, Q. H.; Chang, R. P. H.

    1999-03-01

    We report the first observation of random laser action with coherent feedback in semiconductor powder. Since the scattering mean free path is less than the emission wavelength, recurrent light scattering arises and provides coherent feedback for lasing. Discrete lasing modes have been observed above the threshold. The dependence of the lasing threshold intensity on the excitation volume agrees with the random laser theory. Laser emission from the powder could be observed in all directions. This observation also provides direct evidence for the existence of recurrent scattering of light.

  13. Characterization of Hafnia Powder Prepared from an Oxychloride Sol Gel

    SciTech Connect

    McGilvery, Catriona M. [Imperial College, London; De Gendt, S [Imperial College, London; Payzant, E Andrew [ORNL; MacKenzie, M [Imperial College, London; Craven, A J [Imperial College, London; McComb, D W [Imperial College, London

    2011-01-01

    Hafnium containing compounds are of great importance to the semiconductor industry as a replacement for Si(O,N) with a high- gate dielectric. Whilst Hf is already being incorporated into working devices1, much is still to be understood about it. Here we investigate the crystallisation processes and chemistry of bulk HfO2 powders which will aid in interpretation of reactions and crystallisation events occurring in thin films used as gate dielectrics. Amorphous HfO2 powder was prepared via a sol-gel route using hafnium oxychloride (HfOCl2 xH2O) as a precursor. The powders were subjected to various heat treatments and analysed using x-ray diffraction (XRD) and thermal analysis techniques. It was found that a large change in the crystallisation pathway occurred when the sample was heated in an inert environment compared with in air. Instead of the expected monoclinic phase (m-HfO2), tetragonal HfO2 (t-HfO2) also formed under these conditions and was observed up to temperatures of ~760 C. The t-HfO2 particles, which are less than 30nm in size, eventually transform into m-HfO2 on further heating. Possible mechanisms for the crystallisation of t-HfO2 are discussed. It is proposed that within this temperature range t-HfO2 is stabilised due to the presence of oxygen vacancies in the inert environment, forming by the reduction of HfIV to HfIII. As the crystal grows in size as the temperature increases there are too few oxygen vacancies left in the structure to continue stabilising the t-HfO2 phase and so transformation to m-HfO2 occurs.

  14. Combustion characteristics of the heat pellet prepared from the Fe powders obtained by spray pyrolysis

    Microsoft Academic Search

    J. H. Kim; H. Y. Koo; S. K. Hong; J. M. Han; H. C. Jang; Y. N. Ko; Y. J. Hong; Y. C. Kang; S. H. Kang; S. B. Cho

    Fe powders for thermal batteries were prepared by reduction of iron oxide powders obtained by spray pyrolysis. The iron oxide powders prepared by spray pyrolysis had fine size, spherical shape and high surface area. The morphologies of the Fe powders were affected by the preparation temperatures of the iron oxide powders. The Fe powders obtained from the iron oxide powders

  15. Magnetic Properties of Amorphous Fe-Si-B Powder Cores Mixed with Pure Iron Powder

    NASA Astrophysics Data System (ADS)

    Kim, Hyeon-Jun; Nam, Seul Ki; Kim, Kyu-Sung; Yoon, Sung Chun; Sohn, Keun-Yong; Kim, Mi-Rae; Sul Song, Yong; Park, Won-Wook

    2012-10-01

    Amorphous Fe-Si-B alloy was prepared by melt-spinning, and then the ribbons were pulverized and ball-milled to make the amorphous powder of ˜25 µm in size. Subsequently those were mixed with pure iron powders with an average particle size of 3 µm, and 1.5 wt % water glass diluted by distilled water at the ratio of 1:2. The powder mixtures were cold compacted at 650 MPa in toroid die, and heat treated at 430-440 °C under a nitrogen atmosphere for 1 h and 30 min, respectively. The soft magnetic properties of powder core were investigated using a B-H analyzer and a flux meter at the frequency range of ˜100 kHz. The microstructure was observed using scanning electron microscope (SEM), and the density of the core was measured using the principle of Archimedes. Based on the experimental results, the amorphous powder mixed with pure iron powder showed the improved powder compactability, which resulted in the increased permeability and the reduced core loss.

  16. Rapid Quantitative Analyses of Elements on Herb Medicine and Food Powder Using TEA CO2 Laser-Induced Plasma

    NASA Astrophysics Data System (ADS)

    Khumaeni, Ali; Ramli, Muliadi; Idris, Nasrullah; Lee, Yong Inn; Kurniawan, Koo Hendrik; Lie, Tjung Jie; Deguchi, Yoji; Niki, Hideaki; Kagawa, Kiichiro

    2009-03-01

    A novel technique for rapid quantitative analyses of elements on herb medicine and food powder has successfully been developed. In this technique, the powder samples were plugged in a small hole (2 mm in diameter and 3 mm in depth) and covered by a metal mesh. The Transversely Excited Atmospheric (TEA) CO2 laser (1500 mJ, 200 ns) was focused on the powder sample surfaces passing through the metal mesh at atmospheric pressure of nitrogen surrounding gas. It is hypothesized that the small hole functions to confine the powder particles and suppresses the blowing-off, while the metal mesh works as the source of electrons to initiate the strong gas breakdown plasma. The confined powder particles are subsequently ablated by the laser irradiation and the ablated particles move into the strong gas breakdown plasma region to be atomized and excited. Using this method, a quantitative analysis of the milk powder sample containing different concentrations of Ca was successfully demonstrated, resulting in a good linear calibration curve with high precision.

  17. Improved Small-Particle Powders for Plasma Spraying

    NASA Technical Reports Server (NTRS)

    Nguyen, QuynhGiao, N.; Miller, Robert A.; Leissler, George W.

    2005-01-01

    Improved small-particle powders and powder-processing conditions have been developed for use in plasma spray deposition of thermal-barrier and environmental barrier coatings. Heretofore, plasma-sprayed coatings have typically ranged in thickness from 125 to 1,800 micrometers. As explained below, the improved powders make it possible to ensure complete coverage of substrates at unprecedently small thicknesses of the order of 25 micrometers. Plasma spraying involves feeding a powder into a hot, high-velocity plasma jet. The individual powder particles melt in the plasma jet as they are propelled towards a substrate, upon which they splat to build up a coating. In some cases, multiple coating layers are required. The size range of the powder particles necessarily dictates the minimum thickness of a coating layer needed to obtain uniform or complete coverage. Heretofore, powder particle sizes have typically ranged from 40 to 70 micrometers; as a result, the minimum thickness of a coating layer for complete coverage has been about 75 micrometers. In some applications, thinner coatings or thinner coating layers are desirable. In principle, one can reduce the minimum complete-coverage thickness of a layer by using smaller powder particles. However, until now, when powder particle sizes have been reduced, the powders have exhibited a tendency to cake, clogging powder feeder mechanisms and feed lines. Hence, the main problem is one of synthesizing smaller-particle powders having desirable flow properties. The problem is solved by use of a process that begins with a spray-drying subprocess to produce spherical powder particles having diameters of less than 30 micrometers. (Spherical-particle powders have the best flow properties.) The powder is then passed several times through a commercial sifter with a mesh to separate particles having diameters less than 15 micrometers. The resulting fine, flowable powder is passed through a commercial fluidized bed powder feeder into a plasma spray jet.

  18. Synthesis of in-situ TiAl-based composites from elemental powders

    SciTech Connect

    Alman, D.E.; Hawk, J.A.

    1997-02-01

    Alloys and composites based on the intermetallic compound TiAl are emerging as an important class of light-weight, high-temperature structural materials. Recently, it has been recognized that these alloys have applications in industries, such as the automotive industry, where cost is frequently a major concern in materials selection. However, for these alloys to be used in this type of application, new low cost methods for high volume component fabrication are required. One potential fabrication approach is reactive synthesis (also termed combustion synthesis). This technique involves initiating an self-propagating, high-temperature synthesis (SHS) reaction within an intimate mixture of elemental powders. This process has been used to fabricate intermetallics, ceramics and in-situ composites in the form of powders and dense monoliths. SHS reactions tend to initiate at low homologous temperatures of the forming compound (for aluminides near or at the melting point of Al, 660°C), and tend to go to completion in a short period of time (i.e., a few seconds). For some compounds, particularly aluminides, the reaction is ac companied by the formation of transient liquid phases. These factors can reduce the required processing parameters (time, temperature and pressure) needed to produce dense products by reactive synthesis techniques compared to conventional powder metallurgical approaches. This paper characterizes the reactions that occur and resultant microstructures of TiAl based composites fabricated from ternary mixtures of elemental Ti, Al and B or Si powders. Mixtures of the elemental powders were prepared corresponding to TiAl reinforced with 0, 10 25, 60 and 100 vol. pct. Ti5Si3 or TiB2. The powders were consolidated by reactive hot-pressing (at 1000°C and 20 MPa for 1 hr). It was found that the composites produced from Ti, Al and Si powders were dense, and the elemental powders transformed to the target phases of TiAl and Ti5Si3. Whereas, composites produced from the Ti, Al and B powders were porous and inhomogeneous, that is several aluminide (TiAl, Ti3Al and TiAl3) and boride phases (TiB2, AlB12, TiB) formed during hot-pressing. The different behavior observed by the two ternary systems can be attributed to both reaction sequence and phase diagram considerations. First, Differential Thermal Analysis (DTA) revealed that an endothermic reaction associated with the formation of Al-Si eutectic occurs prior to the initiation of an SHS reaction within the mixtures of Ti, Al and Si powders. No such pre-reaction melting occurred within the mixtures of Ti, Al, and B powders. Thus, the "extra" transient liquid phase that formed during the reaction between Ti, Al and Si systems enhances diffusion (hence homogenization) and densification within this system during reaction processing. Also, an examination of phase diagrams reveals that there exists no Al-Si compounds to compete with the formation of titanium-aluminide and titanium-silicides during reactions between Ti, Al and Si powders. However, there are several aluminum-boride phases that can compete with the formation of titanium-aluminide and titanium-boride during reactions between Ti, Al and B powders. The implications of this study is that TiAl-based composites can be designed for densification during reactive processing.

  19. Laboratory Powder Metallurgy Makes Tough Aluminum Sheet

    NASA Technical Reports Server (NTRS)

    Royster, D. M.; Thomas, J. R.; Singleton, O. R.

    1993-01-01

    Aluminum alloy sheet exhibits high tensile and Kahn tear strengths. Rapid solidification of aluminum alloys in powder form and subsequent consolidation and fabrication processes used to tailor parts made of these alloys to satisfy such specific aerospace design requirements as high strength and toughness.

  20. Balanced mechanical resonator for powder handling device

    NASA Technical Reports Server (NTRS)

    Sarrazin, Philippe C. (Inventor); Brunner, Will M. (Inventor)

    2012-01-01

    A system incorporating a balanced mechanical resonator and a method for vibration of a sample composed of granular material to generate motion of a powder sample inside the sample holder for obtaining improved analysis statistics, without imparting vibration to the sample holder support.

  1. Sol-Gel Synthesis Of Aluminoborosilicate Powders

    NASA Technical Reports Server (NTRS)

    Bull, Jeffrey; Leiser, Daniel; Selvaduray, Guna

    1992-01-01

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

  2. Numerical Simulation of Aerated Powder Consolidation 1

    E-print Network

    will slowly escape by diffusing through the material. The corresponding uneven gas pressure distribution properties. Over time the excess air diffuses through the powder and eventually escapes through the top) d d p 2 FIG. 1. Geometry and coordinate systems for the vertical conical bunker. The height

  3. High-Performance Polyimide Powder Coatings

    NASA Technical Reports Server (NTRS)

    Leahy, Jonathan J.

    2014-01-01

    Researchers at NASA's Kennedy Space Center have developed advanced powder coatings for longer-lasting, improved corrosion control. The results of preliminary tests of the coatings and their resistance to salt spray corrosion are very encouraging, and commercial partners are sought for further development.

  4. Magnetic properties of dispersed magnetite powders

    Microsoft Academic Search

    L. G. Parry

    1965-01-01

    Measurements have been made of coercive force, susceptibility, isothermal remanence, thermoremanence and thermal and alternating field demagnetization of annealed magnetite powders in nine size ranges from 1·5 ? to 120 ?. The samples were dispersed in plaster to occupy a few per cent by volume of the specimens and thus to simulate the magnetic properties of rocks. The results are

  5. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    EPA Science Inventory

    The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

  6. Plated Metal Powders for Electrode Pastes

    NASA Technical Reports Server (NTRS)

    Bickler, D. B.

    1984-01-01

    Metal grains to be sintered precoated with frit metal. Coated metal powders used to make ink-like electrode pastes for printing and sintering electrode-fabrication process. Grains of base metal coated with lowmelting-point--, lead or tin-- by electroless deposition.

  7. Strengthening of face packing surfaces with powders

    Microsoft Academic Search

    N. N. Dorozhkin; V. N. Gimelfarb; L. P. Kashitsyn

    1983-01-01

    The Institute of Problems of Reliability and Life of Machines of the Academy of Sciences of the Belorussian SSR has developed a process of induction coalescing under the action of an activating pressure at the sintering temperature of powder under conditions of accelerated heating and realization of the so-called effect of limited space. Proposed is a method for strengthening the

  8. Thin transparent films formed from powdered glass

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Glass film less than five mils thick is formed from powdered glass dispersed in an organic liquid, deposited on a substrate, and fused into place. The thin films can be cut and shaped for contact lenses, optical filters and insulating layers.

  9. Electrohydraulic-impulse pressing of refractory powders

    Microsoft Academic Search

    K. N. Bogoyavlenskii; P. A. Kuznetsov; K. K. Mertens; V. V. Podgornyi; L. V. Kravets; V. M. Yam

    1982-01-01

    Conclusions It was experimentally established that it is possible to use electrohydraulic-impulse pressing to improve the basic physical properties of articles prepared from low-plasticity refractory powders. The advantages of making articles by combined pressing, including static pressing in a rigid mold and final electrohydraulic-impulse pressing were demonstrated.

  10. Cold spray deposition of thermoplastic powder

    Microsoft Academic Search

    Y. Xu; I. M. Hutchings

    2006-01-01

    The cold spray deposition of polyolefin powder has been investigated, at substantially lower velocities (up to ?135 m s?1) than those used in the cold gas dynamic spray (CGDS) process for metals. The particles were accelerated at room temperature in air through a cylindrical nozzle, and were deposited on to polyethylene and aluminium substrates. Fully-dense deposits were formed at temperatures substantially

  11. Problems of powder flow in tabletting processes

    Microsoft Academic Search

    J. A. Hersey

    1965-01-01

    Summary The flow of non-compacted granules in the tablet machine hopper is discussed with relevance to the unit dose of drug, which is required to be dispensed. The various factors used to describe powder flow such as angle of repose, interparticulate cohesion and friction, flow through apertures, bulk density and die fillability are considered. The effects of humidity and of

  12. Metal Powder ProcessingMetal Powder Processing ME 4210: Manufacturing Processes and Engineering

    E-print Network

    Colton, Jonathan S.

    shields Valve inserts, bushings, gears Electrical/electronic Heat treating Joining Lubrication Ag, Au, Mo is called greenp p g compact. (b) Typical tool and die set for compacting a spur gear. Source: Metal Powder

  13. Consolidation of aluminum 6061 powder by equal channel angular extrusion 

    E-print Network

    Pearson, John Montgomery

    1997-01-01

    Equal channel angular extrusion is a promising approach to obtaining full density in powder metallurgy applications. This method can impose large effective deformations through uniform shear strain. Aluminum alloy 6061 powder is used as a test...

  14. Rheological and Thermal Debinding Behaviors in Titanium Powder Injection Molding

    NASA Astrophysics Data System (ADS)

    Park, Seong-Jin; Wu, Yunxin; Heaney, Donald F.; Zou, Xin; Gai, Guosheng; German, Randall M.

    2009-01-01

    Powder injection molding (PIM) is suitable for the fabrication of complex shape titanium and its alloys and has a great potential in many applications. This article deals with the injection molding of hydride-dehydride (HDH) titanium powder, spheroidized HDH titanium powder, and gas-atomized (GA) titanium powder. Rheological and thermal debinding behaviors are compared between feedstocks made from the three powders. Torque and capillary rheometers are used to investigate rheological behavior as it relates to the power-law model of viscosity and moldability index. Thermogravimetric analysis (TGA) was employed to analyze debinding behavior given a master decomposition curve consisting of two sigmoids. Spheroidized HDH Ti powder behaves in a manner similar to GA Ti powder. The analysis of the results in this study indicates the possibility of using a combination of HDH and GA titanium powders for PIM.

  15. 21 CFR 520.2613 - Trimethoprim and sulfadiazine powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Trimethoprim and sulfadiazine powder. 520.2613 Section 520...DRUGS § 520.2613 Trimethoprim and sulfadiazine powder. (a) Specifications...of trimethoprim and 333 milligrams of sulfadiazine. (b) Sponsor. See No....

  16. 21 CFR 520.2613 - Trimethoprim and sulfadiazine powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Trimethoprim and sulfadiazine powder. 520.2613 Section 520...DRUGS § 520.2613 Trimethoprim and sulfadiazine powder. (a) Specifications...of trimethoprim and 333 milligrams of sulfadiazine. (b) Sponsor. See No....

  17. 21 CFR 520.2613 - Trimethoprim and sulfadiazine powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Trimethoprim and sulfadiazine powder. 520.2613 Section 520...DRUGS § 520.2613 Trimethoprim and sulfadiazine powder. (a) Specifications...of trimethoprim and 333 milligrams of sulfadiazine. (b) Sponsor. See No....

  18. 21 CFR 520.2613 - Trimethoprim and sulfadiazine powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Trimethoprim and sulfadiazine powder. 520.2613 Section 520...DRUGS § 520.2613 Trimethoprim and sulfadiazine powder. (a) Specifications...of trimethoprim and 333 milligrams of sulfadiazine. (b) Sponsor. See No....

  19. 21 CFR 520.2613 - Trimethoprim and sulfadiazine powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Trimethoprim and sulfadiazine powder. 520.2613 Section 520...DRUGS § 520.2613 Trimethoprim and sulfadiazine powder. (a) Specifications...of trimethoprim and 333 milligrams of sulfadiazine. (b) Sponsor. See No....

  20. Kinetics of bacterial death by heated dolomite powder slurry

    Microsoft Academic Search

    Jun Sawai; Kyoko Himizu; Osamu Yamamoto

    2005-01-01

    The kinetics of the bactericidal action of dolomite powders heated at 600–1000°C against Escherichia coli and Staphylococcus aureus were investigated. Dolomite powder heated to at least 700°C exhibited bactericidal action, and the process of bacterial death in the heated dolomite powder slurries followed first-order reaction kinetics. The value of the death rate constant (k) increased with dolomite powder concentration, and

  1. High temperature shock consolidation of hard ceramic powders

    NASA Astrophysics Data System (ADS)

    Hokamoto, K.; Tanaka, S.; Fujita, M.; Itoh, S.; Meyers, M. A.; Chen, H.-C.

    1997-02-01

    High-temperature shoch consolidation of hard ceramic powders was used as a means to improve bonding between powders and to decrease the number of cracks generated in the consolidated sample. A converging underwater shock-wave assembly was used for the compaction, and TiB 2, c-BN and their mixed powders were consolidated at various conditions up to 850°C. The positive effects by heating the powders were confirmed by the experiments conducted.

  2. Aero-sol-gel Reactor for Nano-powder Synthesis

    Microsoft Academic Search

    G. Beaucage; J. Hyeon-Lee; D. J. Kohls; S. E. Pratsinis

    1999-01-01

    This paper discusses a new approach to the synthesis of nano-structured oxides where sol-gel reactions are carried out in aerosol droplets. This aero-sol-gel (ASG) reactor allows for manipulation of the structure, chemical composition and surface area of silica powders through variation of process parameters. ASG powders differ in nanostructure from other continuous process powders such as pyrolytic and solution-route powders.

  3. Calculation of laser absorption by metal powders in additive manufacturing.

    PubMed

    Boley, C D; Khairallah, S A; Rubenchik, A M

    2015-03-20

    We have calculated the absorption of laser light by a powder of metal spheres, typical of the powder employed in laser powder-bed fusion additive manufacturing. Using ray-trace simulations, we show that the absorption is significantly larger than its value for normal incidence on a flat surface, due to multiple scattering. We investigate the dependence of absorption on powder content (material, size distribution, and geometry) and on beam size. PMID:25968537

  4. Study on starch- graft-acrylamide\\/mineral powder superabsorbent composite

    Microsoft Academic Search

    Jihuai Wu; Yueling Wei; Jianming Lin; Songbai Lin

    2003-01-01

    A novel starch-graft-acrylamide\\/mineral powder superabsorbent composite with water absorbency about 4000 times is synthesized by graft-copolymerization reaction among acrylamide, potato starch and mineral ultrafinepowder, followed by hydrolysis with sodium hydroxide. It is found that the composite doped with kaolinite powder possess higher water absorbency than those doped with bentonite or sercite powder, since the kaolinite powder can moderately disperse in

  5. Sintering characteristics of highly active UO2 powder

    SciTech Connect

    Saiki, Wataru; Onoue, Takeshi; Hasegawa, Shinichi [Mitsubishi Metal Company, Ibaraki (Japan)] [and others

    1995-12-31

    A highly active UO{sub 2} powder of 5 to 15m{sup 2}/g specific surface area can be obtained by a conversion process we have developed. This powder can be sintered to high density at a lower temperature than conventional powder; thus, the sintering temperature can be lowered in the manufacturing plant. In this study, sintering characteristics of the active powder, such as correlation of density with temperature, grain growth with sintering time, etc., have been evaluated.

  6. Improved 3-omega measurement of thermal conductivity in liquid, gases, and powders using a metal-coated optical fiber

    Microsoft Academic Search

    Scott N. Schiffres; Jonathan A. Malen

    2011-01-01

    A novel 3omega thermal conductivity measurement technique called metal-coated 3omega is introduced for use with liquids, gases, powders, and aerogels. This technique employs a micron-scale metal-coated glass fiber as a heater\\/thermometer that is suspended within the sample. Metal-coated 3omega exceeds alternate 3omega based fluid sensing techniques in a number of key metrics enabling rapid measurements of small samples of materials

  7. Improved 3-omega measurement of thermal conductivity in liquid, gases, and powders using a metal-coated optical fiber

    Microsoft Academic Search

    Scott N. Schiffres; Jonathan A. Malen

    2011-01-01

    A novel 3? thermal conductivity measurement technique called metal-coated 3? is introduced for use with liquids, gases, powders, and aerogels. This technique employs a micron-scale metal-coated glass fiber as a heater?thermometer that is suspended within the sample. Metal-coated 3? exceeds alternate 3? based fluid sensing techniques in a number of key metrics enabling rapid measurements of small samples of materials

  8. Substitution of Micron by Nanometer Scale Powders in Magnetorheological Fluids

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Wang, G.; Wereley, N. M.; Tasovksi, Vasil; Radhakrishnan, R.

    The effects of substitution of micron size powder by nanometer size powder in magnetorheological (MR) fluids are investigated in this study. Three MR fluid samples containing iron powder with 45% weight fraction in a carrier fluid were made by Materials Modification Inc. The difference among these three fluids is size of the magnetic particles. The first MR fluid sample contained only micron size iron powder with 10?m particle size. In the second sample, 5% micron iron was substituted with nano powders having 30~40nm mean diameter, while the third sample had 37.5% micron powder and 7.5% nano powder. Rheological tests were conducted on the three samples using a parallel disk rheometer. Highest yield stress was observed in the second MR fluid sample containing 40% micron and 5% nano iron powder. By replacing only 5% micron iron powder with nanoparticles, we achieved substantial increment in yield stress. However, when nano powder content is increased to 7.5%, the yield stress decreases and is lower than that in the all micron MR fluid. Thus, by doping a reasonable percent of nano iron powder in the MR fluid, a substantial change in the rheological characteristics is obtainable. Further investigations of effects of nano iron powder in MR fluids for higher weight fraction MR fluids will be carried out in future.

  9. Engineering Our work is focused on the study of Powder

    E-print Network

    powder transport and burning, electrostatic precipitation and heat transfer. At CCNY, he did researchChemical Engineering Abstract Our work is focused on the study of Powder Mechanics and the ultimate goal is to develop a quantitative description of flows for a wide variety of powders using a continuous

  10. Heating of metallic powders by microwaves: Experiment and theory

    Microsoft Academic Search

    V. D. Buchelnikov; D. V. Louzguine-Luzgin; G. Xie; S. Li; N. Yoshikawa; M. Sato; A. P. Anzulevich; I. V. Bychkov; A. Inoue

    2008-01-01

    It is known that bulk metallic samples reflect microwaves while powdered samples can absorb such radiation and be heated efficiently. In the present work we studied heating mechanisms of metallic powders in a multimode 2.45 GHz microwave applicator. The present paper shows direct evidence of penetration of a layer of metallic powder by microwave radiation and provides theoretical explanation of

  11. 21 CFR 176.350 - Tamarind seed kernel powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2009-04-01 true Tamarind seed kernel powder. 176.350 Section 176.350...of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a...

  12. 21 CFR 176.350 - Tamarind seed kernel powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Tamarind seed kernel powder. 176.350 Section 176.350...of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a...

  13. 21 CFR 176.350 - Tamarind seed kernel powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Tamarind seed kernel powder. 176.350 Section 176.350...of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a...

  14. 21 CFR 176.350 - Tamarind seed kernel powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Tamarind seed kernel powder. 176.350 Section 176.350...of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a...

  15. 21 CFR 176.350 - Tamarind seed kernel powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Tamarind seed kernel powder. 176.350 Section 176.350...of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a...

  16. Free radical interactions between raw materials in dry soup powder.

    PubMed

    Raitio, Riikka; Orlien, Vibeke; Skibsted, Leif H

    2011-12-01

    Interactions at the free radical level were observed between dry ingredients in cauliflower soup powder, prepared by dry mixing of ingredients and rapeseed oil, which may be of importance for quality deterioration of such dry food products. The free radical concentrations of cauliflower soup powder, obtained by electron spin resonance (ESR) spectroscopy, rapidly become smaller during storage (40°C and relative humidity of 75%) than the calculated concentrations of free radicals based on the free radical concentrations of the powder ingredients used to make the soup powder and stored separately under similar conditions. Similarly, free radical concentrations decreased faster when any combination of two powder ingredients (of the three major ingredients of the soup powder) were mixed together and stored at 50°C for 1week than when each powder component was stored separately. Furthermore, yeast extract powder was found to play a key role when free radical interactions between powder ingredients occurred. The incubation of rapeseed oil with powder ingredients at 45°C for 24h, indicated the ability of cauliflower powder to increase the concentration of hydroperoxides in rapeseed oil, while yeast extract powder was found to prevent this hydroperoxide formation. PMID:25212323

  17. Spouting of fine powder from vertically vibrated bed

    Microsoft Academic Search

    S. Harada; H. Li; K. Funatsu; Y. Tomita

    2002-01-01

    Experimental and numerical studies of spouting of powder from vertically vibrated bed are performed. The powder flows out vigorously through a side orifice of the vertically vibrated vessel in which the powder is contained, provided that the vibration acceleration is greater than the gravitational one. The mechanism of the efflux and the relationship between the efflux rate and the vibration

  18. 21 CFR 169.182 - Vanilla-vanillin powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Vanilla-vanillin powder. 169.182 Section 169.182 Food...Dressings and Flavorings § 169.182 Vanilla-vanillin powder. (a) Vanilla-vanillin powder conforms to the definition and...

  19. 21 CFR 169.182 - Vanilla-vanillin powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Vanilla-vanillin powder. 169.182 Section 169.182 Food...Dressings and Flavorings § 169.182 Vanilla-vanillin powder. (a) Vanilla-vanillin powder conforms to the definition and...

  20. 21 CFR 169.182 - Vanilla-vanillin powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Vanilla-vanillin powder. 169.182 Section 169.182 Food...Dressings and Flavorings § 169.182 Vanilla-vanillin powder. (a) Vanilla-vanillin powder conforms to the definition and...

  1. 49 CFR 173.171 - Smokeless powder for small arms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Smokeless powder for small arms. 173.171 Section 173.171 Transportation Other Regulations...Class 1 and Class 7 § 173.171 Smokeless powder for small arms. Powders that have been classed in Division 1.3 or...

  2. 49 CFR 173.171 - Smokeless powder for small arms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Smokeless powder for small arms. 173.171 Section 173.171 Transportation...Class 7 § 173.171 Smokeless powder for small arms. Smokeless powder for small arms which has been classed in Division 1.3...

  3. 49 CFR 173.170 - Black powder for small arms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Black powder for small arms. 173.170 Section 173.170 Transportation...and Class 7 § 173.170 Black powder for small arms. Black powder for small arms that has been classed in Division 1.1 may...

  4. 49 CFR 173.170 - Black powder for small arms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 false Black powder for small arms. 173.170 Section 173.170 Transportation...and Class 7 § 173.170 Black powder for small arms. Black powder for small arms that has been classed in Division 1.1 may...

  5. 49 CFR 173.170 - Black powder for small arms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Black powder for small arms. 173.170 Section 173.170 Transportation...and Class 7 § 173.170 Black powder for small arms. Black powder for small arms that has been classed in Division 1.1 may...

  6. 49 CFR 173.171 - Smokeless powder for small arms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 false Smokeless powder for small arms. 173.171 Section 173.171 Transportation...Class 7 § 173.171 Smokeless powder for small arms. Smokeless powder for small arms which has been classed in Division 1.3...

  7. 49 CFR 173.171 - Smokeless powder for small arms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Smokeless powder for small arms. 173.171 Section 173.171 Transportation...Class 7 § 173.171 Smokeless powder for small arms. Smokeless powder for small arms which has been classed in Division 1.3...

  8. Barium strontium titanate powders prepared by spray pyrolysis

    Microsoft Academic Search

    G. Brankovi?; Z. Brankovi?; M. S. Góes; C. O. Paiva-Santos; M. Cilense; J. A. Varela; E. Longo

    2005-01-01

    Ultasonic spray pyrolysis (SP) has been investigated for the production of the barium strontium titanate (BST) powders from the polymeric precursors. The processing parameters, such as flux of aerosol and temperature profile inside the furnace, were optimized to obtain single phase BST. The powders were characterized by the methods of X-ray diffraction analysis, SEM, EDS and TEM. The obtained powders

  9. Manufacture and application of high milk protein powder1

    E-print Network

    Boyer, Edmond

    Review Manufacture and application of high milk protein powder1 Vikram V. MISTRY MN-SD Dairy Foods was developed for the production of a high milk protein powder that was rich in both milk proteins, casein with the most lactose, such as skim milk powder, had the most wrinkles. The virtual absence of lactose

  10. Interaction in polysilazane/SiC powder systems

    SciTech Connect

    Boiteux, Y.P.

    1992-07-01

    Consolidation of ceramic precursor ceramic powder systems upon heating is investigated. A polysilazane (silicon nitride precursor) is chosen as ceramic precursor with a filler of a sub-micron SiC powder. A scheme to optimize the volume fraction of precursor is developed in order to maximize the density of the compacted samples in the green state. Different techniques are presented to improve the homogeneity of precursor distribution in the mixture. A microencapsulation technique is developed that leads to a uniform coating of precursor on individual SiC particles. Upon pyrolysis of systems with 20 wt% polysilazane, little shrinkage occurs. The SiC particles do not coarsen during the heat treatment. The precursor, upon pyrolysis, transforms into an amorphous ceramic phase that acts as a cement between SiC particles. This cement phase can remain amorphous up to 1500{degrees}C; and is best described as a siliconoxycarbide with or without traces of nitrogen. Elimination of nitrogen in the amorphous phase indicates that the filler material (SiC) has a strong influence on the pyrolysis behavior of the chosen polysilazane. The amorphous ceramic phase may crystallize between 1400 and 1500{degrees}C, and depending on the nature of the gas environment, the crystalline phases are SiC, Si or Si{sub 3}N{sub 4}. Mechanisms explaining the strength increase upon heat treatment are proposed. Redistribution of the precursor occurs by capillary forces or vapor phase diffusion and recondensation of volatile monomers. The confined pyrolysis of the precursor results in an increase of residual ceramic matter being decomposed inside the sample. Interfacial reaction between the native silica-rich surface layer on SiC particles and the precursor derived phase explains the high strength of the materials.

  11. Calibration independent generalized cavity method for microwave characterization of powdered materials

    NASA Astrophysics Data System (ADS)

    Jha, Abhishek Kumar; Azizurrahaman; Akhtar, Mohammad Jaleel

    2015-06-01

    A generalized cavity method relaxing the major assumptions of conventional cavity perturbation technique is presented for characterization of the powdered sample in the microwave frequency range. The unified method, which is based on the inverse optimization technique, eliminates the complexity of measurement caused due to the existence of sample holder and produces an accurate result. In this paper, an attractive numerical calibration approach is proposed in lieu of the practical calibration technique which usually requires either a set of standards or a number of reference samples. The sample holder especially made of borosilicate glass is designed to contain the powdered samples, and the X-band rectangular cavity is fabricated. For verification of the proposed technique, the pulverized alumina and polyethylene oxide with various packing fractions are measured using the fabricated cavity and the vector network analyzer. The dielectric constant of these samples is extracted using the proposed unified approach which is found to be in good agreement with the theoretical data obtained by Landau-Lifshitz and Looyenga model. The accuracy of the proposed generalized cavity method for powdered samples is found to be better than the conventional resonator methods available in the literature.

  12. Characterization of pharmaceutical powder inhalers: estimation of energy input for powder dispersion and effect of capsule device configuration

    Microsoft Academic Search

    Nora Y. K. Chew; Hak-Kim Chan; David F. Bagster; Jay Mukhraiya

    2002-01-01

    The present study was aimed to examine (i) the overall energy input (Edispersion) into two capsule-type pharmaceutical powder inhalers, the Dinkihaler® and the Rotahaler®, and (ii) the effect due to the presence of capsule, on powder dispersion using mannitol as a model compound.Powder dispersion was assessed by a liquid impinger with the fine particle fraction (FPF) defined as the wt.%

  13. To evaluate the effect of various magnesium stearate polymorphs using powder rheology and thermal analysis.

    PubMed

    Okoye, Patrick; Wu, Stephen H; Dave, Rutesh H

    2012-12-01

    The effects of magnesium stearate (MgSt) polymorphs-anhydrate (MgSt-A), monohydrate (MgSt-M), and dihydrate (MgSt-D)-on rheological properties of powders were evaluated using techniques such as atomic analysis and powder rheometry. Additional evaluation was conducted using thermal analysis, micromeritics, and tableting forces. In this study, binary ratios of neat MgSt polymorphs were employed as lubricants in powder blends containing acetaminophen (APAP), microcrystalline cellulose (MCC), and lactose monohydrate (LAC-M). Powder rheometry was studied using permeability, basic flow energy (BFE), density, and porosity analysis. Thermal conductivity and differential scanning calorimetric analysis of MgSt polymorphs were employed to elucidate MgSt effect on powder blends. The impact of MgSt polymorphs on compaction characteristics were analyzed via tablet compression forces. Finally, the distribution of atomized magnesium (Mg) ions as a function of intensity was evaluated using laser-induced breakdown spectroscopy (LIBS) on tablets. The results from LIBS analysis indicated the dependency of the MgSt polymorphic forms on the atomized Mg ion intensity, with higher Mg ion intensity suggesting higher lubricity index (i.e. greater propensity to over-lubricate). The results from lubricity index suggested the tendency of blends to over-lubricate based on the MgSt polymorphic forms. Finally, tableting forces suggested that MgSt-D and MgSt-A offered processing benefits such as lower ejection and compression forces, and that MgSt-M showed the most stable compression force in single or combined polymorphic ratios. These results suggested that the initial moisture content, crystal arrangement, intra- and inter-molecular packing of the polymorphs defined their effects on the rheology of lubricated powders. PMID:22304483

  14. Weavability of dry polymer powder towpreg

    NASA Technical Reports Server (NTRS)

    Hugh, Maylene K.; Marchello, Joseph M.; Maiden, Janice R.; Johnston, Norman J.

    1993-01-01

    Carbon fiber yarns (3k, 6k, 12k) were impregnated with LARC (tm) thermoplastic polyimide dry powder. Parameters for weaving these yarns were established. Eight-harness satin fabrics were successfully woven from each of the three classes of yarns and consolidated into test specimens to determine mechanical properties. It was observed that for optimum results warp yarns should have flexural rigidities between 10,000 and 100,000 mg-cm. Tow handling minimization, low tensioning, and tow bundle twisting were used to reduce fiber breakage, the separation of filaments, and tow-to-tow abrasion. No apparent effect of tow size or twist was observed on either tension or compression modulus. However, fiber damage and processing costs favor the use of 12k yarn bundles versus 3k or 6k yarn bundles in the weaving of powder-coated towpreg.

  15. Complex hydrides - when powder diffraction needs help.

    PubMed

    Schouwink, Pascal; Cerný, Radovan

    2014-01-01

    'Real life' energy-related materials such as solid-state hydrogen storage compounds or components of electrochemical cells are usually polycrystalline, poorly crystallized, highly reactive and dynamic systems. Powder diffraction at modern high brilliance X-ray sources is the most useful tool to investigate such systems because it is easy, fast and extremely versatile with respect to measurement conditions as well as in situ setups. However, it is in the nature of these systems that they undergo processes that cannot be investigated by diffraction alone. The central role in hydrogen storage materials is played by hydrogen itself, the worst X-ray scatterer in the periodic system. Gas release, the purpose of a hydrogen storage material, is not detected by diffraction. Amorphous components are badly characterized. We want to show how a complementary approach combining different methods allows to overcome limitations imposed on powder diffraction by the sample nature of 'real' hydrogen storage materials. PMID:24801695

  16. Fabricating solid carbon porous electrodes from powders

    DOEpatents

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

    1997-06-10

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

  17. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    NASA Technical Reports Server (NTRS)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  18. Low-Flow-Rate Dry-Powder Feeder

    NASA Technical Reports Server (NTRS)

    Ramsey, Keith E.

    1994-01-01

    Apparatus feeds small, precise flow of dry powder through laser beam of optical analyzer, measuring patterns of light created by forward scattering (Fraunhofer diffraction) of laser beam from powder particles. From measurement, statistical distribution of sizes of powder particles computed. Developed for analyzing particle-size distributions of solid-propellant powders. Also adapted to use in pharmaceutical industry, in manufacture of metal powder, and in other applications in which particle-size distributions of materials used to control rates of chemical reactions and/or physical characteristics of processes.

  19. Low-Flow-Rate Dry-Powder Feeder

    NASA Technical Reports Server (NTRS)

    Ramsey, Keith E.

    1994-01-01

    Apparatus feeds small, precise flow of dry powder through laser beam of optical analyzer measuring patterns of light created by forward scattering (Fraunhofer diffraction) of laser beam from powder particles. From this optical measurement, statistical distribution of sizes of powder particles computed. Rates of flow optimized for measurement of particle-size distributions. Developed for analyzing particle-size distributions of solid-propellant powders. Also adapted to pharmaceutical industry, in manufacture of metal powder, and in other applications where particle-size distributions of materials used to control rates of chemical reactions and/or physical characteristics of processes.

  20. The reflection of very cold neutrons from diamond powder nanoparticles

    E-print Network

    V. V. Nesvizhevsky; E. V. Lychagin; A. Yu. Muzychka; A. V. Strelkov; G. Pignol; K. V. Protasov

    2008-05-17

    We study possibility of efficient reflection of very cold neutrons (VCN) from powders of nanoparticles. In particular, we measured the scattering of VCN at a powder of diamond nanoparticles as a function of powder sample thickness, neutron velocity and scattering angle. We observed extremely intense scattering of VCN even off thin powder samples. This agrees qualitatively with the model of independent nanoparticles at rest. We show that this intense scattering would allow us to use nanoparticle powders very efficiently as the very first reflectors for neutrons with energies within a complete VCN range up to $10^{-4}$ eV.

  1. The analysis of powder diffraction data

    Microsoft Academic Search

    M. J. Cooper

    1982-01-01

    A comparison has been carried out between the results of analyses of several sets of neutron powder diffraction data using three different methods: the Rietveld method (H. M. Rietveld, Acta. Cryst. 22, 151–152 (1967): J. Appl. Cryst. 2, 65–71 (1969), a modification of the Rietveld method to include off-diagonal terms in the weight matrix (C. P. Clarke and J. S.

  2. The analysis of powder diffraction data

    Microsoft Academic Search

    M. J. Cooper

    1982-01-01

    A comparison has been carried out between the results of analyses of several sets of neutron powder diffraction data using three different methods: the Rietveld method (H. M. Rietveld, Acta. Cryst. 22, 151-152 (1967): J. Appl. Cryst. 2, 65-71 (1969), a modification of the Rietveld method to include off-diagonal terms in the weight matrix (C. P. Clarke and J. S.

  3. Strengthening of face packing surfaces with powders

    Microsoft Academic Search

    N. N. Dorozhkin; V. N. Gimelfarb; L. P. Kashitsyn

    1983-01-01

    The primary reason for failure of centrifugal pumps used in chemical fiber production plants is failure of the tightness of the rubbing surfaces of the face packing surfaces caused by mechanical-corrosion wear. To increase the life, coatings of Ni-Cr-B-Si selffluxing alloy powders are normally applied to their working surface. A process has been developed for induction coalescing under the action

  4. Substantiating powder metal life methodologies for engines

    Microsoft Academic Search

    P. A. Domas

    1993-01-01

    The application of powder metal (PM) superalloys in aircraft turbine engine rotating components is prompted by performance driven high strength and creep resistance requirements. Fine grain, precipitation strengthened nickel-base alloys such as IN100, Rene'95, and Rene'88DT meet these requirements up to operating temperatures in the 1200-1300F (649-704C) range. In addition to burst and deformation limits, design constraints include durability (fatigue)

  5. Photolytic decomposition of lithium aluminum hydride powder

    Microsoft Academic Search

    P. J. Herley; D. H. Spencer

    1979-01-01

    The ultraviolet photolysis of powdered LiAlHâ has been investigated at room temperature by using pristine material and material subjected to ⁶°Co ..gamma..-ray irradiation. In all sampls, similar shaped pressure vs. time curves are obtained that comprise an initial deceleratory period followed by a constant rate of hydrogen gas evolution. The data curves can be resolved into one saturating-exponential component and

  6. Welding of a powder metallurgy uranium alloy

    Microsoft Academic Search

    R. K. Holbert; M. W. Doughty; G. M. Alexander-Morrison

    1989-01-01

    The interest at the Oak Ridge Y-12 Plant in powder metallurgy (P\\/M) uranium parts is due to the potential cost savings in the fabrication of the material, to achieving a more homogeneous product, and to the reduction of uranium scrap. The joining of P\\/M uranium-6 wt-% niobium (U-6Nb) alloys by the electron beam (EB) welding process results in weld porosity.

  7. Powder specific active dispersion for generation of pharmaceutical aerosols.

    PubMed

    Crowder, T; Hickey, A

    2006-12-11

    Dry powder inhalers are increasingly employed to deliver pharmaceutical aerosols. Efficient mechanisms of particle dispersion are central to their success in disease therapy. Creation of a powder aerosol requires the input of energy to transition the static powder bed into an entrained aerosol. The purpose of this study was to investigate the effects of input of vibrational energy into a powder on aerosol entrainment. Rotating drum characterization of powder flow was performed on lactose and maltodextrin excipients blended with albuterol sulfate. Dispersion experiments were conducted using an entrainment tube and a vibration actuator, vibrational energy input being derived from analysis of powder flow data from rotating drum analysis. Results of analysis of the rotating drum data showed that with increasing rotational speed powders reached a constant state of fluidization with a mean avalanche time dependent on the powder. Dispersion experiments demonstrated that the input of vibrational energy increased the dose emission while the input of frequencies specific to the powders improved the reproducibility. Frequency analysis of the vibration signals indicated that the reproducibility was determined by the bandwidth of the signal. This work suggests that an ability to tailor energy input to match the flow properties of a given powder formulation may significantly improve reproducibility of dose delivery from active dry powder inhalers. PMID:16930884

  8. Whey Protein/Polysaccharide-Stabilized Oil Powders for Topical Application-Release and Transdermal Delivery of Salicylic Acid from Oil Powders Compared to Redispersed Powders.

    PubMed

    Kotzé, Magdalena; Otto, Anja; Jordaan, Anine; du Plessis, Jeanetta

    2015-08-01

    Oil-in-water (o/w) emulsions are commonly converted into solid-like powders in order to improve their physical and chemical stabilities. The aim of this study was to investigate whether whey protein/polysaccharide-stabilized o/w emulsions could be converted into stable oil powders by means of freeze-drying. Moreover, during this study, the effects of pH and polymer type on release and trans(dermal) delivery of salicylic acid, a model drug, from these oil powders were investigated and compared to those of the respective template emulsions and redispersed oil powders. Physical characterization of the various formulations was performed, such as droplet size analysis and oil leakage, and relationships drawn with regards to release and trans(dermal) delivery. The experimental outcomes revealed that the oil powders could be redispersed in water without changing the release characteristics of salicylic acid. pH and polymer type affected the release of salicylic acid from the oil powders, template emulsions, and redispersed powders similarly. Contrary, the transdermal delivery from the oil powders and from their respective redispersed oil powders was differently affected by pH and polymer type. It was hypothesized that the release had been influenced by the electrostatic interactions between salicylic acid and emulsifiers, whereas the transdermal performance could have been determined by the particle or aggregate sizes of the formulations. PMID:25573437

  9. The effects of polymer pigmentation on fingermark development techniques.

    PubMed

    Bacon, Simon R; Ojeda, Jesus J; Downham, Rory; Sears, Vaughn G; Jones, Benjamin J

    2013-11-01

    The effectiveness of latent fingerprint development techniques is heavily influenced by the physical and chemical properties of the deposition surface. The use of powder suspensions is increasing for development of prints on a range of surfaces. We demonstrate that carbon powder suspension development on polymers is detrimentally affected by the presence of common white pigment, titanium dioxide. Scanning electron microscopy demonstrates that patches of the compound are clearly associated with increased levels of powder adhesion. Substrates with nonlocalized titanium dioxide content also exhibit increased levels of carbon powder staining on a surface-wide basis. Secondary ion mass spectrometry and complementary techniques demonstrate the importance of levels of the pigment within the top 30 nm. The association is independent of fingermark deposition and may be related to surface energy variation. The detrimental effect of the pigment is not observed with small-particle reagent (MoS2 SPR) or cyanoacrylate (superglue) fuming techniques that exploit different development mechanisms. PMID:23822671

  10. Silicon nitride/silicon carbide composite densified materials prepared using composite powders

    DOEpatents

    Dunmead, S.D.; Weimer, A.W.; Carroll, D.F.; Eisman, G.A.; Cochran, G.A.; Susnitzky, D.W.; Beaman, D.R.; Nilsen, K.J.

    1997-07-01

    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.

  11. Novel diphenyl dimethyl bicarboxylate provesicular powders with enhanced hepatocurative activity: preparation, optimization, in vitro/in vivo evaluation.

    PubMed

    Aburahma, Mona Hassan; Abdelbary, Ghada Ahmed

    2012-01-17

    Diphenyl dimethyl bicarboxylate (DDB) is a hepatocurative agent used for treatment of various liver diseases. However, DDB therapeutic effectiveness is restricted by its low oral bioavailability that arises from its poor solubility and dissolution. Aiming at surmounting the aforementioned restrictions, DDB provesicular dry powders exemplified by proniosomes and proliposomes were prepared using film-deposition technique employing sorbitol as a carrier. Upon dilution with water, the provesicular powders rapidly transformed into vesicular dispersions, either liposomes or niosomes, which were characterized regarding their percent encapsulation efficiency (EE%), vesicle size and distribution, morphology and in vitro drug release. The revealed optimal provesicular powder was exposed to solid state characterization, stability testing and in vivo performance evaluation. Results showed that provesicular powders with acceptable flowability can be prepared using a weight ratio of lipids mixture to sorbitol of 1:20. Proniosomal powder composed of Tween 80:cholesterol:stearylamine in molar ratio 7:3:0.5 loaded on sorbitol was selected as the optimal formulation as it showed the highest EE% and dissolution enhancement for DDB. The elevated levels of liver enzymes in hepatically injured Albino Wister rats were significantly reduced (P<0.05) after oral administration of the optimal proniosomal powder in comparison to free DDB. This improvement was confirmed histopathologically by minimizing the associated hepatic injury. Accordingly, proniosomes can be assertively considered as a promising stable precursor for immediate preparation of niosomal carrier for DDB with enhanced dissolution and hepatocurative activity. PMID:22079716

  12. High-resolution NMR and synchrotron x-ray powder diffraction study of zeolite ZSM-11

    Microsoft Academic Search

    B. H. Toby; M. M. Eddy; C. A. Fyfe; G. T. Kokotailo; H. Strobl; D. E. Cox

    1988-01-01

    High-resolution nuclear magnetic resonance (NMR) spectra and synchrotron x-ray powder diffraction data have been obtained from a well-crystallized highly dealuminated sample of the zeolite ZSM-11. The Rietveld profile technique has been applied to the synchrotron data to give the first detailed refinement of the idealized structure derived ten years ago by distance least-squares modeling methods (G. T. Kokotailo, P. Chu,

  13. Aluminization of high purity iron and stainless steel by powder liquid coating

    Microsoft Academic Search

    Koji Murakami; Norihide Nishida; Kozo Osamura; Yo Tomota; Tetsuya Suzuki

    2004-01-01

    Powder liquid coating is investigated metallographically as an aluminization technique for high-purity iron [Acta Mater., in press] and stainless steel. In this process, Fe2Al5 forms initially during heat treatment, with c axis preferentially aligned with the sample normal. In Fe–18mass%Cr alloy, Cr exhibits almost the same concentration profile as Fe except for the temporary formation of a Cr5Al8 network in

  14. A comparison of bismuth nanoforms obtained in vacuum and air by microwave heating of bismuth powder

    Microsoft Academic Search

    Oxana V. Kharissova; Mario Osorio; Boris I. Kharisov; Miguel José Yacamán; Ubaldo Ortiz Méndez

    2010-01-01

    The synthesis of bismuth nanotubes in the conditions of microwave (MW) heating is reported as a lower-cost and simple technique in comparison with the traditional methods. The nanotubes were prepared by heating the Bi powder (a) in air for 15, 30, 60, and 90min and (b) in vacuum for 5, 10, and 15min in a domestic MW-oven (2.45GHz, 1300W). The

  15. Self-propagating high-temperature (combustion) synthesis (SHS) of powder-compacted materials

    Microsoft Academic Search

    H. C. Yi; J. J. Moore

    1990-01-01

    Self-propagating high-temperature synthesis (SHS) of powder compacts is a novel processing technique currently being developed as a route for the production of engineering ceramics and other advanced materials. The process, which is also referred to as combustion synthesis, provides energy- and cost-saving advantages over the more conventional processing routes for these materials. At the same time, the rapid heating and

  16. Implementation and use of Robust Refinement in Powder Diffraction in the Presence of Impurities

    SciTech Connect

    Stone, K.; Lapidus, S; Stephens, P

    2009-01-01

    A modification to the usual least-squares analysis is implemented for the robust refinement of structural parameters from powder diffraction data in the presence of unmodeled impurities. This is accomplished in the program TOPAS-Academic by an iterative reweighting of the data as the model is refined. The method is tested and characterized using mixtures of known materials, acetaminophen and ibuprofen. The technique is also used to refine two previously unknown structures.

  17. An elasto-viscoplastic constitutive formulation for dry powder compression analysis using finite elements

    NASA Astrophysics Data System (ADS)

    Mittal, Bhavishya

    The aim of this research was to measure, analyze, model, and predict the rate-dependent mechanical behavior of dry powders undergoing compression in a die. Mechanical properties of two ceramic powders (MZF and alumina) were studied up to 14 MPa using a medium pressure flexible boundary cubical triaxial tester (CTT). The powders were subjected to undrained tests along two stress paths and three compression rates of 0.62, 6.21, and 20.7 MPa/minute. Based on test results from compression and shear stress paths, a new elasto-viscoplastic constitutive model (PSU-EVP) was developed for studying the dry powder compression process. The PSU-EVP model was formulated using the critical state theory, the modified Cam-clay model, and the Adachi and Oka model as the basis. Unlike the modified Cam-clay model, the PSU-EVP model explicitly accounts for the work done in the volumetric compression of pore air or gas during dry powder compression. This key feature of the PSU-EVP model helps in isolating the effect of entrapped pore air (or gas) on the mechanical properties of powders. Based on the PSU-EVP constitutive model back-prediction results and sensitivity analysis, it was concluded that the model gave fairly good results for most CTT test data collected at 0.62 MPa/minute and 6.21 MPa/minute. However, the back-prediction results obtained at 20.7 MPa/minute had high average relative difference values (>20%). Overall, the PSU-EVP model can be considered to be the first step towards the development of a more robust and accurate constitutive model for the predicting stress distributions in a dry powder during compression process. A 3D finite element prediction tool (PSU-FEM v2.0 software) was developed to model the powder compression process in an elastic die. The PSU-FEM v2.0 contained a fast iterative solver based on the multigrid method. The results obtained from the multigrid solver were compared with a conventional Gauss-Siedel iterative method, conjugate gradient, and ABAQUS. The results and the trends were in very good quantitative and qualitative agreement with one another (difference <5%). Sparse matrix techniques were incorporated also into the PSU-FEM v2.0 software, which led to a marked decrease in solution time.

  18. Preparation of micro-foils for TEM/STEM analysis from metallic powders.

    PubMed

    Dawson, Karl; Tatlock, Gordon J

    2015-07-01

    A technique has been developed which facilitates the preparation of electro-polished micro-foil transmission electron microscopy (TEM) specimens, which have previously been machined out of ?100?m diameter metallic powder particles using a Focussed Ion Beam (FIB) instrument. The technique can be used to create small volume TEM specimens from most metallic powder particles and bulk metal samples. This is especially useful when the matrices are ferritic steels, which are often difficult to image in the electron microscope, since the necessary aberration corrections change as the sample is tilted in the magnetic field of the objective lens. Small samples, such as powder particles, were attached to gold support grids using deposited platinum and were then ion milled to approximately 2?m thickness in a focussed ion beam (FIB) instrument. Subsequently, the specimen assemblies were electropolished for short durations under standard conditions, to produce large (5?m×5?m) electron transparent regions of material. The specimens produced by this technique were free from FIB related artefacts and facilitated atomic resolution scanning-TEM (STEM) imaging of ferritic and nickel matrices containing, for example, yttrium rich oxide nano-dispersoids. PMID:25967375

  19. Acoustic harmonic generation measurement applications: Detection of tight cracks in powder metallurgy compacts

    NASA Astrophysics Data System (ADS)

    Barnard, D. J.; Foley, J. C.

    2000-05-01

    Standard linear ultrasonic testing techniques have long been employed for locating and characterizing relatively open cracks in a wide variety of materials, from metallic alloys and ceramics to composites. In all these materials, the detection of open cracks easily accomplished because the void between the two crack surfaces provides sufficient acoustic impedance mismatch to reflect the incident energy. Closed or partially closed cracks, however, may often go undetected because contacting interfaces allow transmission of ultrasound. In the green (unsintered) state, powder metallurgy compacts typically contain high residual stresses that have the ability to close cracks formed during the compaction process, a result of oxide films, improper powder lubricant, mold design, etc. After sintering, the reduction of residual stresses may no longer be sufficient to close the crack. Although the crack may be more easily detected, it is obvious most desirable to discover defects prior to sintering. It has been shown that the displacements of an interface may be highly nonlinear if a stress wave of sufficient intensity propagates across it, a result of the stress wave either opening or closing the interface. Current efforts involve the application of nonlinear acoustic techniques, in particular acoustic harmonic generation measurements, for the detection and characterization of tightly closed cracks in powder metallurgy parts. A description of the equipment and the measurement technique will be discussed and initial experimental results on sintered and green compacts will be presented.—This work was performed at the Ames Laboratory, Iowa State University under USDOE Contract No. W-7405-ENG-82.

  20. Structural and spectroscopic analyses of europium doped yttrium oxyfluoride powders prepared by combustion synthesis

    SciTech Connect

    Rakov, Nikifor [PG-Ciência dos Materiais, Universidade Federal do Vale do São Francisco, 48902-300 Juazeiro, BA (Brazil)] [PG-Ciência dos Materiais, Universidade Federal do Vale do São Francisco, 48902-300 Juazeiro, BA (Brazil); Guimarães, R. B.; Maciel, Glauco S. [Instituto de Física, Universidade Federal Fluminense, 24210-346 Niterói, RJ (Brazil)] [Instituto de Física, Universidade Federal Fluminense, 24210-346 Niterói, RJ (Brazil); Lozano B, W. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil)] [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil)

    2013-07-28

    A facile widely spread technique employed to produce low-cost high-yield oxide powders, combustion synthesis, was used to prepare yttrium oxyfluoride crystalline ceramic powders. The structure of the powders was analyzed by X-ray powder diffraction and Rietveld refinement. Samples heat treated at 700 °C had a predominance of vernier orthorhombic Y{sub 6}O{sub 5}F{sub 8} phase, while samples heat treated at 800 °C crystallized in stoichiometric rhombohedral YOF phase. The samples were doped with luminescent europium trivalent ions (Eu{sup 3+}) in different concentrations (1–15 wt.%) and Judd-Ofelt theory was used to probe the distortion from the inversion symmetry of the local crystal field and the degree of covalency between the rare-earth ion and the surrounding ligands. The luminescence lifetime was measured and the luminescence quantum efficiency (LQE) was estimated. We observed that Eu{sup 3+}:Y{sub 6}O{sub 5}F{sub 8} samples presented higher LQE in spite of the larger local crystal field anisotropy found for Eu{sup 3+}:YOF samples.

  1. Si-based print circuit board fabricated by Si deep etching and metal powder injection molding

    NASA Astrophysics Data System (ADS)

    Maeda, Ryutaro; Murakoshi, Yoichi; Shimizu, Toru; Li, Yaomin; Takizawa, Hiroyuki

    2001-03-01

    In this report, Silicon wafer based print circuit board is presented as an example of application of this technique, where the metal was filled into ICP fabricated through holes to make electrical feed through. The target application of this work is Silicon based print circuit board. The electrical feed through was fabricated by casting the Ag (80 wt%) + Cu (20 wt %) mixed with binder into the small diameter through holes in oxidized Silicon wafer. A multi-component binder system comprising of EVA (Ethylene Vinyl Acetate 35 wt%) + PW (Paraffin Wax 65 wt%) was used. Super critical debinding method is applied prior to final sintering process. The ratio of metal powder and binder was 9:1. SEM observation shows that the through holes are filled with metal powders. Conventional debinding process resulted in scattering the metal powder onto the Si wafer during debinding process and final sintering process. Very slow temperature elevation heating and super critical debinding process resulted in good formation of electrical feed through. The feed through formed with small bumps because of expansion of the metal powder area. The electrical conductivity test was sufficient between top and bottom. Several Feed through formation methods have been proposed.

  2. Nano-liposomal dry powder inhaler of Amiloride Hydrochloride.

    PubMed

    Chougule, Mahavir Bhupal; Padhi, Bijay Kumar; Misra, Ambikanandan

    2006-01-01

    The purpose of this study was to encapsulate Amiloride Hydrochloride into nano-liposomes, incorporate it into dry powder inhaler, and to provide prolonged effective concentration in airways to enhance mucociliary clearance and prevent secondary infection in cystic fibrosis. Liposomes were prepared by thin film hydration technique and then dispersion was passed through high pressure homogenizer to achieve size of nanometer range. Nano-liposomes were separated by centrifugation and were characterized. They were dispersed in phosphate buffer saline pH 7.4 containing carriers (lactose/sucrose/mannitol), and glycine as anti-adherent. The resultant dispersion was spray dried. The spray dried powders were characterized and in vitro drug release studies were performed using phosphate buffer saline pH 7.4. In vitro and in vivo drug pulmonary deposition was carried out using Andersen Cascade Impactor and by estimating drug in bronchial alveolar lavage and lung homogenate after intratracheal instillation in rats respectively. Nano-liposomes were found to have mean volume diameter of 198 +/- 15 nm, and 57% +/- 1.9% of drug entrapment. Mannitol based formulation was found to have low density, good flowability, particle size of 6.7 +/- 0.6 microm determined by Malvern MasterSizer, maximum fine particle fraction of 67.6 +/- 0.6%, mean mass aerodynamic diameter 2.3 +/- 0.1 microm, and geometric standard deviation 2.4 +/- 0.1. Developed formulations were found to have prolonged drug release following Higuchi's Controlled Release model and in vivo studies showed maximal retention time of drug of 12 hrs within the lungs and slow clearance from the lungs. This study provides a practical approach for direct lung delivery of Amiloride Hydrochloride encapsulated in liposomes for controlled and prolonged retention at the site of action from dry powder inhaler. It can provide a promising alternative to the presently available nebulizers in terms of prolonged pharmacological effect, reducing systemic side effects such as potassium retention due to rapid clearance of the drug from lungs in patients suffering from cystic fibrosis. PMID:17048511

  3. Preparation and characterization of Pb(Zr 0.52Ti 0.48)O 3 ceramics from high-energy ball milling powders

    Microsoft Academic Search

    L. B Kong; W Zhu; O. K Tan

    2000-01-01

    Ultra-fine Pb(Zr0.52Ti0.48)O3 powder has been synthesized from the commercial PbO, TiO2 and ZrO2 powders using the high-energy ball milling technique in air at room temperature without any post-annealing. The synthesized powders milling for different hours are characterized using XRD, SEM, TEM and Raman spectra. XRD patterns and Raman spectra show that the perovskite phase of PZT can be formed from

  4. Dry powder process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs

    NASA Technical Reports Server (NTRS)

    Wilkinson, Steven P. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

    1997-01-01

    A process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs is provided. A plurality of polymer powder coated filamentary towpregs are provided. The towpregs are collimated so that each towpreg is parallel. A material is applied to each side of the towpreg to form a sandwich. The sandwich is heated to a temperature wherein the polymer flows and intimately contacts the filaments and pressure is repeatedly applied perpendicularly to the sandwich with a longitudinal oscillating action wherein the filaments move apart and the polymer wets the filaments forming a uni-tape prepreg. The uni-tape prepreg is subsequently cooled.

  5. Development of Powder Diffraction Analysis Tools for aNanocrystalline Specimen: An Emphasis upon NiTi (Nitinol)

    Microsoft Academic Search

    Erich Owens

    2006-01-01

    Powder diffraction is a specialized technique whose investigatory limits are constrained by the scale of the crystallized substance being scanned versus the probe beam used. When disparate in scale, with the photon spot size larger than the crystal being probed, many are employed, the resulting diffraction image being cast from all possible incident angles, constructing Ï-arcs containing information about the

  6. FT-IR and XRD characterization of phase transformation of heat-treated synthetic natisite (Na 2TiOSiO 4) powder

    Microsoft Academic Search

    Gow-Weng Peng; Hok-Shing Liu

    1995-01-01

    A sodium titanium silicate polycrystalline powder, natisite (Na2TiOSiO4), has been prepared by a hydrothermal process and heat-treated between 800 and 1500 °C. The phase transformation of natisite has been evaluated by using absorption infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy\\/energy-dispersive spectrometry (SEM\\/ EDS) techniques. The sequence of phase transformation may be divided

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

    Microsoft Academic Search

    H Fujii; K Ozawa; H Kitaguchi

    2012-01-01

    We have studied the effect of planetary ball-milling of filling powder with mineral and silicon oils on the carbon substitution in MgB2 and the critical current density (Jc) of Fe-sheathed MgB2 tapes fabricated through an ex situ process in a powder-in-tube (PIT) technique. The mineral oil is much more effective for the carbon substitution and hence the Jc enhancement of

  8. Large Bore Powder Gun Qualification (U)

    SciTech Connect

    Rabern, Donald A. [Los Alamos National Laboratory; Valdiviez, Robert [Los Alamos National Laboratory

    2012-04-02

    A Large Bore Powder Gun (LBPG) is being designed to enable experimentalists to characterize material behavior outside the capabilities of the NNSS JASPER and LANL TA-55 PF-4 guns. The combination of these three guns will create a capability to conduct impact experiments over a wide range of pressures and shock profiles. The Large Bore Powder Gun will be fielded at the Nevada National Security Site (NNSS) U1a Complex. The Complex is nearly 1000 ft below ground with dedicated drifts for testing, instrumentation, and post-shot entombment. To ensure the reliability, safety, and performance of the LBPG, a qualification plan has been established and documented here. Requirements for the LBPG have been established and documented in WE-14-TR-0065 U A, Large Bore Powder Gun Customer Requirements. The document includes the requirements for the physics experiments, the gun and confinement systems, and operations at NNSS. A detailed description of the requirements is established in that document and is referred to and quoted throughout this document. Two Gun and Confinement Systems will be fielded. The Prototype Gun will be used primarily to characterize the gun and confinement performance and be the primary platform for qualification actions. This gun will also be used to investigate and qualify target and diagnostic modifications through the life of the program (U1a.104 Drift). An identical gun, the Physics Gun, will be fielded for confirmatory and Pu experiments (U1a.102D Drift). Both guns will be qualified for operation. The Gun and Confinement System design will be qualified through analysis, inspection, and testing using the Prototype Gun for the majority of process. The Physics Gun will be qualified through inspection and a limited number of qualification tests to ensure performance and behavior equivalent to the Prototype gun. Figure 1.1 shows the partial configuration of U1a and the locations of the Prototype and Physics Gun/Confinement Systems.

  9. Spray freeze drying for dry powder inhalation of nanoparticles.

    PubMed

    Ali, Mohamed Ehab; Lamprecht, Alf

    2014-08-01

    Formulating nanoparticles for delivery to the deep lung is complex and many techniques fail in terms of nanoparticle stability. Spray freeze drying (SFD) is suggested here for the production of inhalable nanocomposite microcarriers (NCM). Different nanostructures were prepared and characterized including polymeric and lipid nanoparticles. Nanoparticle suspensions were co-sprayed with a suitable cryoprotectant into a cooled, stainless steel spray tower, followed by freeze drying to form a dry powder while equivalent compositions were spray dried (SD) as controls. SFD-NCM possess larger specific surface areas (67-77 m(2)/g) and lower densities (0.02 g/cm(3)) than their corresponding SD-NCM. With the exception of NCM of lipid based nanocarriers, SFD produced NCM with a mass median aerodynamic diameter (MMAD) of 3.0±0.5 ?m and fine particle fraction (FPF?5.2 ?m) of 45±1.6% with aerodynamic performances similar to SD-NCM. However, SFD was superior to SD in terms of maintaining the particle size of all the investigated polymeric and lipid nanocarriers following reconstitution (S(f)/S(i) ratio for SFD?1 versus >1.5 for SD). The SFD into cooled air proved to be an efficient technique to prepare NCM for pulmonary delivery while maintaining the stability of the nanoparticles. PMID:24657824

  10. Low-Cobalt Powder-Metallurgy Superalloy

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1986-01-01

    Highly-stressed jet-engine parts made with less cobalt. Udimet 700* (or equivalent) is common nickel-based superalloy used in hot sections of jet engines for many years. This alloy, while normally used in wrought condition, also gas-atomized into prealloyed powder-metallurgy (PM) product. Product can be consolidated by hot isostatically pressing (HIPPM condition) and formed into parts such as turbine disk. Such jet-engine disks "see" both high stresses and temperatures to 1,400 degrees F (760 degrees C).

  11. Stuck in traffic: Patterns of powder adhesion.

    PubMed

    Nirmal Thyagu, N; Vasilenko, A; Voyiadjis, A; Glasser, B J; Shinbrot, T

    2012-10-01

    The adhesion of fine particles to surfaces is important for applications ranging from drug delivery to fouling of solar cells. In this letter, we show that powder adhesion can occur in unexpected patterns, concentrating particular grain types in some locations and clearing them from others, and we propose a straightforward traffic model that appears to reproduce many of the behaviors seen. The model predicts different patterns depending on inter-particle cohesion, and we find in both experiment and model that adhesion occurs in three distinct stages. PMID:23085956

  12. DOE, Gary testing tertiary polymer technique

    Microsoft Academic Search

    A. Goldburg; P. D. Stevens

    1981-01-01

    A report is given of a pilot demonstration to determine whether micellar-polymer flooding is a technically and economically feasible enhanced recovery technique for use in the Belle Creek field in Powder River County, Montana. The U.S. Department of Energy is sharing the cost of the project. A radioactive tracer survey was conducted during a pattern reorientation waterflood to give information

  13. Physical properties of yoghurt powder produced by spray drying.

    PubMed

    Koç, Banu; Sakin-Y?lmazer, Melike; Kaymak-Ertekin, Figen; Balk?r, P?nar

    2014-07-01

    The study is an extension of an optimization study, which was planned to determine the optimum spray drying conditions (the feed, outlet and inlet air temperatures) for producing yoghurt powder. The resulting yoghurt powder at each condition was subjected to the measurement of physical properties, moisture content, and reconstitution properties. All the reconstitution properties of yoghurt powders produced under 20 different spray drying conditions according to CCRD experimental design were affected by the drying outlet temperature only. Furthermore, the bulk (bulk and tapped densities, porosity, flowability, hygroscopicity and degree of caking) and particle properties (particle size distribution, particle density and morphology) of yoghurt powder obtained from optimum spray drying conditions were also determined. The bulk, tapped and particle densities of yoghurt powder were 538, 746 and 1177 kg/m(3), respectively. The mean diameter (D4.3) and the span value of yoghurt powder were 3.053 and 2.487 ?m, respectively. PMID:24966433

  14. Amorphous powders of Al-Hf prepared by mechanical alloying

    SciTech Connect

    Schwarz, R.B.; Hannigan, J.W.; Sheinberg, H.; Tiainen, T.

    1988-01-01

    We synthesized amorphous Al/sub 50/Hf/sub 50/ alloy powder by mechanically alloying an equimolar mixture of crystalline powders of Al and Hf using hexane as a dispersant. We characterized the powder as a function of mechanical-alloying time by scanning electron microscopy, x-ray diffraction, and differential scanning calorimetry. Amorphous Al/sub 50/Hf/sub 50/ powder heated at 10 K s/sup /minus/1/ crystallizes polymorphously at 1003 K into orthorhombic AlHf (CrB-type structure). During mechanical alloying, some hexane decomposes and hydrogen and carbon are incorporated into the amorphous alloy powder. The hydrogen can be removed by annealing the powder by hot pressing at a temperature approximately 30 K below the crystallization temperature. The amorphous compacts have a diamond pyramidal hardness of 1025 DPH. 24 refs., 7 figs., 1 tab.

  15. The preference of protein powders among adult male and females: A protein powder taste study

    Microsoft Academic Search

    Joshua Manter

    2010-01-01

    Protein is essential in one's diet because it is an important component in many organs and tissues throughout the body. Athletes ingest protein in order to stimulate protein synthesis and increase lean muscle mass. In order to assist with obtaining adequate amounts of protein, athletes and bodybuilders purchase supplemental protein in the form of protein powders. Protein metabolism and digestion

  16. Synthesis of Nanocrystalline ?-Al2O3 Powder Using Acetylacetone

    Microsoft Academic Search

    J. Chandradass; Ki Hyeon Kim

    2009-01-01

    Nanocrystalline ?-Al2O3 powders have been prepared by pyrolysis of a complex compound of aluminum with acetylacetone. The volumetric ratio (alumina to acetylacetone) of the starting feedstock has been shown to be a critical factor for the formation of nano ?-Al2O3 powders. The optimum calcinations temperature of the precursor powder for crystallization of nano ?-Al2O3 was found to be 1000°C for

  17. Need for a comparative performance standard for dry powder inhalers.

    PubMed Central

    Richards, R.; Saunders, M.

    1993-01-01

    The efficacy of dry powder inhalers is dependent on the inspiratory flow rate at which they are used. The resistance to airflow through five different dry powder inhaler devices was measured. The devices were shown to vary significantly, with the Turbohaler having the highest resistance. We suggest that the performance of dry powder inhalers should be assessed at comparable pressure drops producing clinically relevant inspiratory flow rates for each device. Images PMID:8296270

  18. Mach stem characterization in Mbar designs using RSR powder

    SciTech Connect

    Staudhammer, K.P.; Johnson, K.A.

    1985-01-01

    Suitable selection of powders can be used as a modeling device for complicated experimental designs. The powder melt zone is clearly defined and the RSR-834 powder is reasonably well behaved. This experiment was with only one composition, size and distribution. However, it is believed that other morphologies, composition, and size distributions could result in a more complete modeling of the compaction process that would enable heuristic calculations of the combined effects of adiabatic temperature rise and entropic heating (strain/deformation).

  19. Effects of pressure on thermal transport in plutonium oxide powder

    Microsoft Academic Search

    P. Bielenberg; F. C. Prenger; D. K. Veirs; J. Jones

    2004-01-01

    Radial temperature profiles in plutonium oxide (PuO) powder were measured in a cylindrical vessel over a pressure range of 0.055 to 334.4 kPa with two different fill gases, helium and argon. The fine PuO powder provides a very uniform self-heating medium amenable to relatively simple mathematical descriptions. At low pressures (<0.1 kPa), the effective thermal conductivity of the powder bed

  20. Modeling density contributions in preceramic polymer\\/ceramic powder systems

    Microsoft Academic Search

    K. B. Schwartz; D. J. Rowcliffe

    1986-01-01

    A model is presented that examines the mixing of ceramic powders with preceramic polymer binders that are converted to ceramic material on pyrolysis. Such polymer\\/powder systems, which have applications in the compaction of both SiC and Si3N4 powders, can be effective in increasing the green density of die-pressed bodies. This model examines the relative importance of various physical parameters of

  1. Size of snow particles in a powder-snow avalanche

    Microsoft Academic Search

    M. Rastello; F. Rastello; H. Bellot; F. Ousset; F. Dufour

    2009-01-01

    The size of the snow particles involved in a powder-snow ava- lanche is a key parameter of the local dynamic of the flow. An experimental device has been realized to collect snow particles within powder-snow avalanches. Snow particles have been cap- tured in the powder-snow part of an avalanche triggered artifi- cially on the experimental test site of the vallee

  2. Mechanical properties of articles formed from powder alloy steels

    Microsoft Academic Search

    T. A. Pumpyanskaya; N. V. Krokhina; E. M. Fainshmidt

    1989-01-01

    1.The plasticity and impact strength of articles formed from powder Ni-Mo-Cu steel using nickel and molybdenum oxides are two times higher than those attained when this same steel is alloyed with metallic powders of nickel and molybdenum.2.The improved mechanical properties of steels formed from partially alloyed iron powder using nickel and molybdenum oxides are explained by the uniformity of the

  3. Injection molding of TiAl alloyed powder

    Microsoft Academic Search

    Kiyotaka Kato; Yoshihiko Nozaki

    1991-01-01

    To realize manufacturing process of near net shape, titanium aluminide powder injection molding was applied to TiAl alloyed powder. TiAl alloyed powder was mixed with the binder consisting of wax and acrylic resin at the content of 45 vol pct. Flow characteristics of this compound was evaluated by extrusion-type flow meter. Then it was injection-molded to the shape of a

  4. Study of de-watering from the gelatinous precipitate formed during co-precipitation of Nd-YAG powder

    SciTech Connect

    Karmakar, Sanjib; Sharma, Rachna; Pathak, S. K.; Gupta, S. M.; Gupta, P. K. [Laser Materials Development and Devices Division Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

    2013-02-05

    Neodymium doped Yttrium Aluminium Garnet (Nd:YAG) ceramics have been synthesised using coprecipitation technique and high temperature vacuum sintering. Gelatinous like precipitates were obtained when precursors of Nd, Al and Yb-nitrate solutions are co-precipitated using ammonia co-precipitant. De-watering from the gelatinous like precipitates is a big challenge and it possesses difficulty in filtration. Evaporation of water by heating resulted in strong agglomerated powder. Different agents were used to ease the filtration process, which is correlated with the phase in the calcined powder.

  5. Particle-size reduction of Si3N4 powder with Si3N4 milling hardware

    NASA Technical Reports Server (NTRS)

    Herbell, T. P.; Freedman, M. R.; Kiser, J. D.

    1986-01-01

    The grinding of Si3N4 powder using reaction bonded Si3N4 attrition, vibratory, and ball mills with Si3N4 media was examined. The rate of particle size reduction and the change in the chemical composition of the powder were determined in order to compare the grinding efficiency and the increase in impurity content resulting from mill and media wear for each technique. Attrition and vibratory milling exhibited rates of specific surface area increase that were approximately eight times that observed in ball milling. Vibratory milling introduced the greatest impurity pickup.

  6. Powder River coalbed methane output growing fast

    SciTech Connect

    Petzet, G.A.

    1997-03-10

    Operators expect to complete several hundred wells to Cretaceous Fort Union coals this year in the northeastern Powder River basin. Favorable price and purchaser conditions and workable environmental restrictions have spawned a low cost play that has produced nearly 500 intents to drill since mid-1995. Western Gas Resources Inc., Denver, said the Powder River basin coals were delivering about 28 MMcfd of methane at yearend 1996. Another 35 MMcfd is shut-in waiting on connection and pipeline hookup. The coal is in a 40--90 ft seam 150--600 ft deep. All drilling to date has been within 10--12 miles of and downdip from about 18 large open pits from which sub-bituminous Fort Union coals have been mined. None of the coal companies captures or owns any gas. The dominant operators in the play are Western Gas Resources Inc. and Redstone Resources Inc., both of Denver, who have leased about 80% of the known play area in Wyoming. A half dozen others have smaller positions. The paper discusses Western`s plans, low well costs, understanding coals, tending the wells, and scope of the play.

  7. A major advance in powder metallurgy

    NASA Technical Reports Server (NTRS)

    Williams, Brian E.; Stiglich, Jacob J., Jr.; Kaplan, Richard B.; Tuffias, Robert H.

    1991-01-01

    Ultramet has developed a process which promises to significantly increase the mechanical properties of powder metallurgy (PM) parts. Current PM technology uses mixed powders of various constituents prior to compaction. The homogeneity and flaw distribution in PM parts depends on the uniformity of mixing and the maintenance of uniformity during compaction. Conventional PM fabrication processes typically result in non-uniform distribution of the matrix, flaw generation due to particle-particle contact when one of the constituents is a brittle material, and grain growth caused by high temperature, long duration compaction processes. Additionally, a significant amount of matrix material is usually necessary to fill voids and create 100 percent dense parts. In Ultramet's process, each individual particle is coated with the matrix material, and compaction is performed by solid state processing. In this program, Ultramet coated 12-micron tungsten particles with approximately 5 wt percent nickel/iron. After compaction, flexure strengths were measured 50 percent higher than those achieved in conventional liquid phase sintered parts (10 wt percent Ni/Fe). Further results and other material combinations are discussed.

  8. Structural changes during milling of aluminum oxide powders

    NASA Technical Reports Server (NTRS)

    Ziepler, G.

    1984-01-01

    The mechanical activation of four fused corundum powders and a calcined Al2O3 powder was studied. The milled powders were characterized by their structural properties, crystallite size, and lattice distortions. Structural changes during milling, detected by X-ray line broadening analysis, gave information about the enhanced activity of the powders caused by the lattice distortions and by the decreasing crystallite size during milling. The structural changes during milling, under the same milling conditions, can be quite different for the same ceramic material, but with different characteristics in the as received state.

  9. Process for synthesizing compounds from elemental powders and product

    DOEpatents

    Rabin, Barry H. (Idaho Falls, ID); Wright, Richard N. (Idaho Falls, ID)

    1993-01-01

    A process for synthesizing intermetallic compounds from elemental powders. The elemental powders are initially combined in a ratio which approximates the stoichiometric composition of the intermetallic compound. The mixed powders are then formed into a compact which is heat treated at a controlled rate of heating such that an exothermic reaction between the elements is initiated. The heat treatment may be performed under controlled conditions ranging from a vacuum (pressureless sintering) to compression (hot pressing) to produce a desired densification of the intermetallic compound. In a preferred form of the invention, elemental powders of Fe and Al are combined to form aluminide compounds of Fe.sub.3 Al and FeAl.

  10. Controlled powder morphology experiments in megabar 304 stainless steel compaction

    SciTech Connect

    Staudhammer, K.P.; Johnson, K.A.

    1985-01-01

    Experiments with controlled morphology including shape, size, and size distribution were made on 304L stainless steel powders. These experiments involved not only the powder variables but pressure variables of 0.08 to 1.0 Mbar. Also included are measured container strain on the material ranging from 1.5% to 26%. Using a new strain controllable design it was possible to seperate and control, independently, strain and pressure. Results indicate that powder morphology, size distribution, packing density are among the pertinent parameters in predicting compaction of these powders.

  11. Nanocrystalline Rare Earth-doped Gallium Nitride Phosphor Powders

    Microsoft Academic Search

    G. A. Hirata; J. Tao; P. Chen; K. C. Mishra; J. McKittrick

    We report on the fabrication and luminescent properties of rare earth-doped gallium nitride (GaN) phosphor powders. Single phase GaN and GaN:RE3+ powders were prepared by using a novel chemical route. In this work a new method for the synthesis of high purity, single phase doped GaN powders is reported. (Ga1-xREx)N powders are obtained by dissolving metal nitrates (Ga(NO3)3, (RE(NO3)3) in

  12. 21 CFR 866.1640 - Antimicrobial susceptibility test powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Diagnostic Devices § 866.1640 Antimicrobial susceptibility test powder. (a)...

  13. A sample-saving method for heat capacity measurements on powders using relaxation calorimetry

    NASA Astrophysics Data System (ADS)

    Dachs, Edgar; Benisek, Artur

    2011-08-01

    An experimental method is described for determining the low-temperature heat capacity (Cp) of mg-sized powder samples using the Quantum Design “Physical Properties Measurement System” (PPMS). The powder is contained in an Al pan as an ?1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in Cp to better than 1% at T above 30-50 K and ±3-5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC Cp data are used to slightly adjust the PPMS Cp data by a factor C. This is done because heat capacities measured with a DSC device are more accurate around ambient T (?0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures.

  14. A sample-saving method for heat capacity measurements on powders using relaxation calorimetry

    PubMed Central

    Dachs, Edgar; Benisek, Artur

    2011-01-01

    An experimental method is described for determining the low-temperature heat capacity (Cp) of mg-sized powder samples using the Quantum Design “Physical Properties Measurement System” (PPMS). The powder is contained in an Al pan as an ?1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in Cp to better than 1% at T above 30–50 K and ±3–5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC Cp data are used to slightly adjust the PPMS Cp data by a factor CpDSC/CpPPMSat298K. This is done because heat capacities measured with a DSC device are more accurate around ambient T (?0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures. PMID:21886915

  15. A sample-saving method for heat capacity measurements on powders using relaxation calorimetry.

    PubMed

    Dachs, Edgar; Benisek, Artur

    2011-08-01

    An experimental method is described for determining the low-temperature heat capacity (C(p)) of mg-sized powder samples using the Quantum Design "Physical Properties Measurement System" (PPMS). The powder is contained in an Al pan as an ?1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in C(p) to better than 1% at T above 30-50 K and ±3-5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC C(p) data are used to slightly adjust the PPMS C(p) data by a factor CpDSC/CpPPMSat298K. This is done because heat capacities measured with a DSC device are more accurate around ambient T (?0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures. PMID:21886915

  16. Synergy between transmission electron microscopy and powder diffraction: application to modulated structures.

    PubMed

    Batuk, Dmitry; Batuk, Maria; Abakumov, Artem M; Hadermann, Joke

    2015-04-01

    The crystal structure solution of modulated compounds is often very challenging, even using the well established methodology of single-crystal X-ray crystallography. This task becomes even more difficult for materials that cannot be prepared in a single-crystal form, so that only polycrystalline powders are available. This paper illustrates that the combined application of transmission electron microscopy (TEM) and powder diffraction is a possible solution to the problem. Using examples of anion-deficient perovskites modulated by periodic crystallographic shear planes, it is demonstrated what kind of local structural information can be obtained using various TEM techniques and how this information can be implemented in the crystal structure refinement against the powder diffraction data. The following TEM methods are discussed: electron diffraction (selected area electron diffraction, precession electron diffraction), imaging (conventional high-resolution TEM imaging, high-angle annular dark-field and annular bright-field scanning transmission electron microscopy) and state-of-the-art spectroscopic techniques (atomic resolution mapping using energy-dispersive X-ray analysis and electron energy loss spectroscopy). PMID:25827366

  17. Fast, reagentless and reliable screening of "white powders" during the bioterrorism hoaxes.

    PubMed

    W?odarski, Maksymilian; Kaliszewski, Miron; Trafny, El?bieta Anna; Szpakowska, Ma?gorzata; Lewandowski, Rafa?; Bombalska, Aneta; Kwa?ny, Miros?aw; Kopczy?ski, Krzysztof; Mularczyk-Oliwa, Monika

    2015-03-01

    The classification of dry powder samples is an important step in managing the consequences of terrorist incidents. Fluorescence decays of these samples (vegetative bacteria, bacterial endospores, fungi, albumins and several flours) were measured with stroboscopic technique using an EasyLife LS system PTI. Three pulsed nanosecond LED sources, generating 280, 340 and 460nm were employed for samples excitation. The usefulness of a new 460nm light source for fluorescence measurements of dry microbial cells has been demonstrated. The principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been used for classification of dry biological samples. It showed that the single excitation wavelength was not sufficient for differentiation of biological samples of diverse origin. However, merging fluorescence decays from two or three excitation wavelengths allowed classification of these samples. An experimental setup allowing the practical implementation of this method for the real time fluorescence decay measurement was designed. It consisted of the LED emitting nanosecond pulses at 280nm and two fast photomultiplier tubes (PMTs) for signal detection in two fluorescence bands simultaneously. The positive results of the dry powder samples measurements confirmed that the fluorescence decay-based technique could be a useful tool for fast classification of the suspected "white powders" performed by the first responders. PMID:25598484

  18. Direct analysis of herbal powders by pipette-tip electrospray ionization mass spectrometry.

    PubMed

    Wang, Haixing; So, Pui-Kin; Yao, Zhong-Ping

    2014-01-27

    Conventional electrospray ionization mass spectrometry (ESI-MS) is widely used for analysis of solution samples. The development of solid-substrate ESI-MS allows direct ionization analysis of bulky solid samples. In this study, we developed pipette-tip ESI-MS, a technique that combines pipette tips with syringe and syringe pump, for direct analysis of herbal powders, another common form of samples. We demonstrated that various herbal powder samples, including herbal medicines and food samples, could be readily online extracted and analyzed using this technique. Various powder samples, such as Rhizoma coptidis, lotus plumule, great burdock achene, black pepper, Panax ginseng, roasted coffee beans, Fructus Schisandrae Chinensis and Fructus Schisandrae Sphenantherae, were analyzed using pipette-tip ESI-MS and quality mass spectra with stable and durable signals could be obtained. Both positive and negative ion modes were attempted and various compounds including amino acids, oligosaccharides, glycosides, alkaloids, organic acids, ginosensides, flavonoids and lignans could be detected. Principal component analysis (PCA) based on the acquired mass spectra allowed rapid differentiation of closely related herbal species. PMID:24418140

  19. Temperature dependence improvement of luminance in powder electroluminescent cells by modified BaTiO3 powders

    Microsoft Academic Search

    K. Tanaka; M. Toyoda

    1991-01-01

    Luminance of powder electroluminescent cells varies greatly with ambient temperature. This luminance instability can be improved by designing temperature-dependent impedance of an insulating layer. Attempts were made by using modified BaTiO3 ceramic powders as insulating materials. Luminance change has been suppressed below 8% at 20-70°C by a modified BaTiO3 powder having a negative temperature coefficient of the dielectric constant. Luminance

  20. A flash evaporation technique for oxide superconductors

    SciTech Connect

    Davis, M.F.; Wosik, J.; Wolfe, J.C.; Lichtenberg, C.L. (Department of Electrical Engineering, University of Houston, Houston, TX 77004 (USA))

    1989-02-01

    An electron beam flash evaporation technique is presented which can reproduce the stoichiometry of YBa{sub 2}Cu{sub 3}O{sub x} and Bi{sub 2}CaSr{sub 2}Cu{sub 2}O{sub y} source powders. Process details such as source powder degassing and electron beam operating parameters are described. Zero resistance temperatures near 80 K were obtained for both materials. The Bi{sub 2}CaSr{sub 2}Cu{sub 2}O{sub y} films deposited on MgO are highly textured with the c-axis normal to the substrate.