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Sample records for submicrometre-scale single powder

  1. Fabrication of Crack-Free Barium Titanate Thin Film with High Dielectric Constant Using Sub-Micrometric Scale Layer-by-Layer E-Jet Deposition

    Directory of Open Access Journals (Sweden)

    Junsheng Liang

    2016-01-01

    Full Text Available Dense and crack-free barium titanate (BaTiO3, BTO thin films with a thickness of less than 4 μm were prepared by using sub-micrometric scale, layer-by-layer electrohydrodynamic jet (E-jet deposition of the suspension ink which is composed of BTO nanopowder and BTO sol. Impacts of the jet height and line-to-line pitch of the deposition on the micro-structure of BTO thin films were investigated. Results show that crack-free BTO thin films can be prepared with 4 mm jet height and 300 μm line-to-line pitch in this work. Dielectric constant of the prepared BTO thin film was recorded as high as 2940 at 1 kHz at room temperature. Meanwhile, low dissipation factor of the BTO thin film of about 8.6% at 1 kHz was also obtained. The layer-by-layer E-jet deposition technique developed in this work has been proved to be a cost-effective, flexible and easy to control approach for the preparation of high-quality solid thin film.

  2. High pressure single crystal and powder XRD study for neighborite

    Science.gov (United States)

    Liu, H.

    2016-12-01

    After Murakami et al. (2004) identified the post-perovskite (ppv) phase transition in MgSiO3 perovskite (pv) at pressures and temperatures consistent with the onset of Earth's D" layer, lots of post-perovskite type phase transitions were founded in other similar systems. These discoveries provided a better understanding of heterogeneous structures and seismic anisotropy observed in the controversial region of the lower mantle. With previous experimental evidence showing the analogue system of neighborite NaMgF3 will transform from pv to ppv at 30 GPa, we performed high quality single crystal XRD experiment, which led to a more precise structure determination. Using helium as pressure medium, one metastable low symmetric phase before the pv-ppv structure transition was discovered, whose total energy was calculated as well. The comparison between single crystal and powder XRD data will be presented, and potential application will be discussed.

  3. Single-step Coprocessing of Cohesive Powder via Mechanical Dry Coating for Direct Tablet Compression.

    Science.gov (United States)

    Qu, Li; Stewart, Peter J; Hapgood, Karen P; Lakio, Satu; Morton, David A V; Zhou, Qi Tony

    2017-01-01

    This study aims at testing the feasibility of a single-step coating process to produce a powder formulation of active and inactive ingredients for direct compression. A cohesive ibuprofen powder was coprocessed with a coating material, a binder (polyvinylpyrrolidone K25), and a superdisintegrant (crospovidone). Magnesium stearate (MgSt), l-leucine, and silica were selected as coating materials (1% w/w). A coprocessed powder without any coating material was employed as a control. Coating with MgSt, l-leucine, or silica produced significantly improved powder flow in comparison to the control batch. Robust tablets were produced from the processed powders for each coating material. The tablets compacted using the coated powders with MgSt or l-leucine also exhibited significantly lower tablet ejection forces than the control batch, demonstrating their lubrication effect. Furthermore, the disintegration time and dissolution rates of these tablets made of the formulations coprocessed with lubricants were enhanced, even for those coated with the hydrophobic material such as MgSt that has been previously reported to inhibit dissolution. However, the tablets made with silica-coated powders would not disintegrate. This study indicated the feasibility of a single-step dry coating process to produce powders with both flow-aid and lubrication effects, which are suitable for direct compression. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  4. Fabrication of Single-Phase NiTi by Combustion Synthesis of Mechanically Activated Powders

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    S. Mousavi Nasab

    2012-01-01

    Full Text Available Single-phase NiTi was fabricated through the thermal explosion mode of combustion synthesis of mechanically activated powders. Combustion and ignition temperatures of combustion synthesis were investigated in different milling times. In this process, equiatomic powder mixtures of nickel and titanium were activated by planetary ball mill and pressed into disk-shaped pellets then heated in a tube furnace, while temperature-time profile was recorded. X-ray diffraction analysis (XRD was performed on milled powders as well as synthesized samples. Scanning electron microscopy (SEM was also used to study the microstructural evolution during milling. The results showed that there was a threshold milling time to obtain single-phase NiTi. It was also seen that the ignition temperature and combustion temperature were reduced significantly by increasing milling time.

  5. Synthesis, characterization and formation mechanism of single-phase nanostructure bredigite powder

    Energy Technology Data Exchange (ETDEWEB)

    Mirhadi, S.M., E-mail: Mirhadi@iaush.ac.ir [Department of Ceramic Engineering, Shahreza Branch, Islamic Azad University, 86145-311, Shahreza, Isfahan (Iran, Islamic Republic of); Tavangarian, F.; Emadi, R. [Department of Materials Engineering, Isfahan University of Technology (IUT), Isfahan 84156-83111 (Iran, Islamic Republic of)

    2012-02-01

    Single-phase nanocrystalline bredigite powder was successfully synthesized by mechanical activation of talc, calcium carbonate, and amorphous silica powder mixture followed by annealing. Simultaneous thermal analysis (STA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS),and Fourier transform infrared spectroscopy (FT-IR) techniques were employed to characterize various powders. Single-phase nanostructure bredigite powder with crystallite size of about 65 nm was synthesized by 20 h of mechanical activation with subsequent annealing at 1200 Degree-Sign C for 1 h. The bredigite formation mechanism was studied. During the formation process of nanostructure bredigite powder some intermediate compounds such as wollastonite (CaSiO{sub 3}), larnite (Ca{sub 2}SiO{sub 4}), merwinite (Ca{sub 3}MgSi{sub 2}O{sub 8}), and calcium magnesium silicate (Ca{sub 5}MgSi{sub 3}O{sub 12}) were formed. It was found that bredigite was not produced directly and that the formation of merwinite, enstatite and Ca{sub 5}MgSi{sub 3}O{sub 12}was unavoidable during the synthesis of bredigite. - Graphical abstract: This paper reports the successful synthesis of nanostructure bredigite powder by mechanical activation with subsequent annealing. The results showed that during the formation of bredigite powder some transition compounds such as wollastonite (CaSiO{sub 3}), larnite (Ca{sub 2}SiO{sub 4}), merwinite (Ca{sub 3}MgSi{sub 2}O{sub 8}), and calcium magnesium silicate (Ca{sub 5}MgSi{sub 3}O{sub 12}) were formed. Highlights: Black-Right-Pointing-Pointer Mechanical activation improved the kinetics of bredigite formation. Black-Right-Pointing-Pointer A mechanism was suggested for the nanostructure bredigite formation. Black-Right-Pointing-Pointer During the formation of bredigite powder some intermediate compounds were formed. Black-Right-Pointing-Pointer The nanostructure bredigite powder had a mean crystallite

  6. Features of the incorporation of single and double based powders within emulsion explosives

    Science.gov (United States)

    Ribeiro, J. B.; Mendes, R.; Tavares, B.; Louro, C.

    2014-05-01

    In this work, features of the thermal and detonation behaviour of compositions resulting from the mixture of single and double based powders within ammonium nitrate based emulsion explosives are shown. Those features are portrayed through results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential thermal analysis [DTA] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the "gap-test". DTA/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical species and so of the compatibility of the components of the compositions. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with powder than for the one with sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have been shown to be higher for the powdered compositions than for the sole emulsion explosive. Shock sensitivity assessments have ended-up with a slightly bigger sensitivity for the compositions with double based powder when compared to the single based compositions or to the sole emulsion.

  7. Features of the Valorization of Single and Double Based Powders for Codetonation in Emulsion Explosives

    Science.gov (United States)

    Ribeiro, Jose; Mendes, Ricardo; Tavares, Bruno; Louro, Cristina

    2013-06-01

    In this work, features of the thermal and detonation behavior of compositions resulting from the mixture of single and double based gun powder within ammonium nitrate (AN) based emulsion explosives are shown. That includes results of thermodynamic-equilibrium calculations of the detonation velocity, the chemical compatibility assessment through differential scanning calorimetry [DSC] and thermo gravimetric analysis [TGA], the experimental determination of the detonation velocity and a comparative evaluation of the shock sensitivity using a modified version of the ``gap-test''. DSC/TGA results for the compositions and for the individual components overlap until the beginning of the thermal decomposition which is an indication of the absence of formation of any new chemical specimens and so of the capability of the composition components. After the beginning of the thermal decomposition it can be seen that the rate of mass loss is much higher for the compositions with gun powder than for the sole emulsion explosive. Both, theoretical and experimental, values of the detonation velocity have shown to be higher for the powdered compositions than for the pure emulsion explosive. Shock sensitivity assessment have ended-up with a slightly bigger sensitivity for the compositions with double based gun powder when compared to the single based compositions or to the pure emulsion.

  8. Preparation of single phase {beta}-spodumene powders by sol-gel process

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Shawbing; Yang, Sheng [National Cheng-Kung University, Tainan (Taiwan). Dept. of Resources Engineering; Chen, Jenmin; Wu, Nangchung [National Cheng-Kung University, Tainan (Taiwan). Dept. of Material Science and Engineering; Wang, Moochin [National Kaohsiung Institute of Technology, Kaohsiung (Taiwan). Dept. of Mechanical Engineering

    1999-12-01

    The {beta}-spodumene (Li{sub 2}O{center_dot}Al{sub 2}O{sub 3}{center_dot}4SiO{sub 2}, LAS) powders were prepared by the sol-gel process using a mixture of silica sol, alumina sol and lithium nitrate solution. Si(OC{sub 2}H{sub 5}){sub 4}, Al(OC{sub 4}H{sub 9}{sup 8ec}){sub 3} and LiNO{sub 3} were used as the starting compounds. Thermogravimetric and differential thermal analyses (TG/DTA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), wavelength-dispersive spectroscopy (WDS), transmission electron microscopy (TEM) and electron diffraction (ED) analysis were utilized to characterize the {beta}-spodumene powders prepared by the sol-gel process. The crystallization temperature of the LAS gel powder estimated by TG/DTA was about 630 degree C. When the LAS dried gel was heated from 600 to 850 degree C, the crystallized powders of the single phase {beta}-spodumene were obtained. (author)

  9. Modelling and Characterization of Effective Thermal Conductivity of Single Hollow Glass Microsphere and Its Powder.

    Science.gov (United States)

    Liu, Bing; Wang, Hui; Qin, Qing-Hua

    2018-01-14

    Tiny hollow glass microsphere (HGM) can be applied for designing new light-weighted and thermal-insulated composites as high strength core, owing to its hollow structure. However, little work has been found for studying its own overall thermal conductivity independent of any matrix, which generally cannot be measured or evaluated directly. In this study, the overall thermal conductivity of HGM is investigated experimentally and numerically. The experimental investigation of thermal conductivity of HGM powder is performed by the transient plane source (TPS) technique to provide a reference to numerical results, which are obtained by a developed three-dimensional two-step hierarchical computational method. In the present method, three heterogeneous HGM stacking elements representing different distributions of HGMs in the powder are assumed. Each stacking element and its equivalent homogeneous solid counterpart are, respectively, embedded into a fictitious matrix material as fillers to form two equivalent composite systems at different levels, and then the overall thermal conductivity of each stacking element can be numerically determined through the equivalence of the two systems. The comparison of experimental and computational results indicates the present computational modeling can be used for effectively predicting the overall thermal conductivity of single HGM and its powder in a flexible way. Besides, it is necessary to note that the influence of thermal interfacial resistance cannot be removed from the experimental results in the TPS measurement.

  10. From single excipients to dual excipient platforms in dry powder inhaler products.

    Science.gov (United States)

    Shur, Jagdeep; Price, Robert; Lewis, David; Young, Paul M; Woollam, Grahame; Singh, Dilraj; Edge, Stephen

    2016-12-05

    Recent years have seen a marked diversification of excipient based formulation strategies used for the development and commercialisation of dry powder inhaler (DPI) products. These innovative approaches not only provide benefits to patients and health care professionals through the availability of a wider range of therapeutic DPI products, but, importantly, also allow formulators to exploit the potential opportunities that excipients provide for the development of DPIs. Whilst many DPI products have, and continue to be developed using a single formulation excipient, the commercialisation of DPI products which contain the two excipients lactose monohydrate and magnesium stearate, namely the 'dual excipient platform' has recently been achieved. This article provides an overview of the background and current status of the development of such 'dual excipient platform' based DPI products. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  11. Improving accuracy of overhanging structures for selective laser melting through reliability characterization of single track formation on thick powder beds

    DEFF Research Database (Denmark)

    Mohanty, Sankhya; Hattel, Jesper Henri

    2016-01-01

    establishing reliability of overhanging structure production by selective laser melting has been adopted. A calibrated, fast, multiscale thermal model is used to simulate the single track formation on a thick powder bed. Single tracks are manufactured on a thick powder bed using same processing parameters......, and subjected to uncertainty and reliability analysis. Cumulative probability distribution functions obtained for melt track widths and depths are found to be coherent with observed experimental values. The technique is subsequently extended for reliability characterization of single layers produced on a thick...... modelling has been adopted towards improving the predictability of the outputs from the selective laser melting process. Establishing the reliability of the process, however, is still a challenge, especially in components having overhanging structures.In this paper, a systematic approach towards...

  12. A mechanochemical route to single phase Cu{sub 2}ZnSnS{sub 4} powder

    Energy Technology Data Exchange (ETDEWEB)

    Ritscher, A. [Institut für Chemie, Technische Universität Berlin, Straße des 17.Juni 135, 10623 Berlin (Germany); Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Just, J. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Fachbereich C- Physik, Bergische Universität Wuppertal, Gaußstr. 20, 42119 Wuppertal (Germany); Dolotko, O. [Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr.1, 85748 Garching (Germany); Schorr, S. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74, 12249 Berlin (Germany); Lerch, M., E-mail: martin.lerch@tu-berlin.de [Institut für Chemie, Technische Universität Berlin, Straße des 17.Juni 135, 10623 Berlin (Germany)

    2016-06-15

    With respect to absorber materials in solar cells, Cu{sub 2}ZnSnS{sub 4} (CZTS) has been a focus of interest in recent years. In this work, a new route leading to single phase CZTS powders is presented. For structural characterization X-ray and neutron powder diffraction measurements were performed. Further structural and compositional analysis of the CZTS powder was carried out by means of X-ray absorption near edge spectroscopy (XANES) and wavelength-dispersive X-ray spectroscopy (WDS). The obtained CZTS powder with an actual composition of Cu{sub 2.00(4)}Zn{sub 1.02(2)}Sn{sub 0.99(2)}S{sub 4.00(8)} adopts the kesterite-type structure. A detailed cation distribution analysis using the average neutron scattering length method revealed a partial disorder of copper and zinc on the (2c) and (2d) sites. - Highlights: • Mechanochemical synthesis of phase pure kesterite powder. • Determination of the cation distribution using neutron diffraction. • Partial disorder for copper and zinc observed.

  13. Analysis of morphology and residual porosity in selective laser melting of Fe powders using single track experiments

    Science.gov (United States)

    Shutov, I. V.; Gordeev, G. A.; Kharanzhevskiy, E. V.; Krivilyov, M. D.

    2017-04-01

    Morphology and residual porosity of single tracks obtained by pulse selective laser melting (SLM) of Fe powder have been studied by metallography. Multiple cross sections of the stainless substrate with the single tracks deposited by SLM are examined and classified depending on processing parameters. A sustainable scanning strategy to reduce residual porosity is suggested for pulse laser annealing. The developed method is suitable both for improvement of processing regimes in commercial SLM machines and validation of numerical models in additive manufacturing of metal parts. The effect of the beam radius, pulse energy, its frequency and duration on a shape of the single track and its adhesion to the substrate is revealed.

  14. Replication assessment of surface texture at sub-micrometre scale

    DEFF Research Database (Denmark)

    Quagliotti, Danilo; Tosello, Guido; Hansen, Hans Nørgaard

    2017-01-01

    -parts and parts with micro and nano surfaces is still in progress and requires new specially developed solutions in all the steps of injection molding processes [1]. The achievement of a full surface replication of the tool insert component, when molding the polymer melt, is essential in advanced μIM technology......Precision molding and micro injection molding (μIM) have been the main replication technologies allowing for a rapid reduction of the dimensions of the products and, consequently, for the realization of new advanced micro and nano systems. Such miniaturization in the manufacture of polymer micro...

  15. Fabrication of water-dispersible single-walled carbon nanotube powder using N-methylmorpholine N-oxide

    Science.gov (United States)

    Choi, Hyejun; Woo, Jong Seok; Tark Han, Joong; Park, Soo-Young

    2017-11-01

    Dispersion of nanocarbon materials in liquid media, via solution processing such as spraying, printing, spinning, etc. is one of the prerequisites for practical applications. Here we report that water-dispersible single-walled carbon nanotubes (SWCNTs) were prepared through successive treatments with chlorosulfuric acid (CSA)/H2O2 and N-methylmorpholine N-oxide (NMO) monohydrate. The powder of the CSA/H2O2- and NMO-treated SWCNTs (N-SWCNTs) could be readily redispersed in water in concentrations as high as 1 g l‑1 without requiring a dispersant. The mechanism responsible for the high dispersity of the N-SWCNT powder in polar solvents, including water, was elucidated based on the high polarity of the NMO molecule. In order to highlight the wide applicability of the N-SWCNTs, they were used successfully to prepare conducting thin films by spray-coating plastic substrates with an aqueous hybrid solution containing the N-SWCNTs and Ag nanowires (NWs). In addition, a flexible, large-area thin-film heater was prepared based on the N-SWCNT/AgNW hybrid film with a transmittance of 93% and sheet resistance of 30 Ω sq‑1.

  16. Thermal behavior in single track during selective laser melting of AlSi10Mg powder

    Science.gov (United States)

    Wei, Pei; Wei, Zhengying; Chen, Zhen; He, Yuyang; Du, Jun

    2017-09-01

    A three-dimensional model was developed to simulate the radiation heat transfer in the AlSi10Mg packed bed. The volume of fluid method (VOF) was used to capture the free surface during selective laser melting (SLM). A randomly packed powder bed was obtained using discrete element method (DEM) in Particle Flow Code (PFC). The proposed model has demonstrated a high potential to simulate the selective laser melting process (SLM) with high accuracy. In this paper, the effect of the laser scanning speed and laser power on the thermodynamic behavior of the molten pool was investigated numerically. The results show that the temperature gradient and the resultant surface tension gradient between the center and the edge of the molten pool increase with decreasing the scanning speed or increasing the laser power, thereby intensifying the Marangoni flow and attendant turbulence within the molten pool. However, at a relatively high scanning speed, a significant instability may be generated in the molten pool. The perturbation and instability in the molten pool during SLM may result in an irregular shaped track.

  17. About some practical aspects of X-ray diffraction : From single crystal to powders

    Energy Technology Data Exchange (ETDEWEB)

    Giacovazzo, C. [Bari Univ. (Italy). Dip. Geomineralogico

    1996-09-01

    An ideal polycrystalline material or power is an ensemble of a very large number of randomly oriented crystallites. It is shown the effect that this random orientation has on the diffraction of a specimen assumed to contain only one reciprocal lattice node. The most remarkable difference with the single-crystal case is that now must think of scattering vectors not as lying on discrete nodes of reciprocal lattice vectors, the distances from the single-crystal reciprocal lattice nodes to the origin of reciprocal space.

  18. Performance of Dry Powder Inhalers with Single Dosed Capsules in Preschool Children and Adults Using Improved Upper Airway Models

    Directory of Open Access Journals (Sweden)

    Sandra Lindert

    2014-02-01

    Full Text Available The pulmonary administration of pharmaceutical aerosols to patients is affected by age-dependent variations in the anatomy of the upper airways and the inhalation pattern. Considering this aspect, different upper airway models, representing the geometries of adults and preschool children, and a conventional induction port according to the European Pharmacopeia were used for in vitro testing of dry powder inhalers with single dosed capsules (Cyclohaler®, Handihaler® and Spinhaler®. Deposition measurements were performed using steady flow rates of 30 and 60 L/min for the Handihaler®/Spinhaler® and 30, 60 and 75 L/min for the Cyclohaler®. The inhalation volume was set at 1 L. For the Cyclohaler®, the in vitro testing was supplemented by a pediatric inhalation profile. Slight differences of pulmonary deposition between the idealized adult (11%–15% and pediatric (9%–11% upper airway model were observed for the Cyclohaler®. The applied pediatric inhalation profile resulted in a reduction of pulmonary deposition by 5% compared to steady conditions and indicated the influence of the inhalation pattern on the amount of pulmonary deposited particles. The comparison of two pediatric upper airway models showed no differences. The performance of the Handihaler® was similar to the Cyclohaler®. The Spinhaler® showed an insufficient performance and limited reproducibility in our investigations.

  19. Characteristics of Single-Track and Multi-track Depositions of Stellite by Micro-plasma Transferred Arc Powder Deposition Process

    Science.gov (United States)

    Sawant, Mayur S.; Jain, N. K.

    2017-08-01

    This paper describes the characteristics study of single-track and multi-track deposition of Stellite 6 on AISI 4130 steel substrate by indigenously developed micro-plasma transferred arc powder deposition (μ-PTAPD) process. Deposition height and width, dilution and microstructure have been used to characterize the single-track depositions by studying effects of micro-plasma power, travel speed of worktable and powder mass flow rate on energy consumption per unit traverse length and power consumption per unit powder mass flow rate. Micro-plasma power was found to be the most influential parameter that affects energy and deposition material consumption. Consequently, its influence on micro-hardness and abrasion resistance of multi-track deposition was studied. Results showed that increase in micro-plasma power decreases micro-hardness and scratch hardness number and increases mean value of friction coefficient. Comparison of microstructure and chemical composition of single-track and multi-track depositions revealed that single-track has finer dendritic microstructure than the multi-track deposition. The black colored matrix and white colored dendrites present in the multi-track deposition have higher wt.% of cobalt and less wt.% of chromium than the single-track deposition. Comparison of µ-PTAPD process capabilities with the existing processes for Stellite deposition establishes that it is an energy-efficient, cost-effective and good quality deposition yielding process.

  20. Hybrid Powder - Single Crystal X-Ray Diffraction Instrument for Planetary Mineralogical Analysis of Unprepared Samples Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a planetary exploration XRD/XRF instrument based on a hybrid diffraction approach that complements powder XRD analysis, similar to that of the...

  1. Influence of adhesive thickness and filler content on the mechanical performance of aluminum single-lap joints bonded with aluminum powder filled epoxy adhesive

    OpenAIRE

    Kahraman, R.; M. Sunar; Yilbas, B.

    2007-01-01

    The objective of this study was to develop information on the influence of adhesive thickness and aluminum filler content on the mechanical performance of aluminum joints bonded by aluminum powder filled epoxy. The adhesive strength of the joints was determined by utilizing the single-lap shear test. The influence of adhesive thickness and aluminum filler content on stress distribution within the adhesive was also analyzed by finite element method (FEM). Both FEM analysis and the experimental...

  2. Preparation of LuAG Powders with Single Phase and Good Dispersion for Transparent Ceramics Using Co-Precipitation Method

    Directory of Open Access Journals (Sweden)

    Liangjie Pan

    2015-08-01

    Full Text Available The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h with high terminal pH value (>7.80 resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.

  3. Delivery characteristics and patients’ handling of two single-dose dry-powder inhalers used in COPD

    Directory of Open Access Journals (Sweden)

    Chapman KR

    2011-06-01

    Full Text Available Kenneth R Chapman1, Charles M Fogarty2, Clare Peckitt3, Cheryl Lassen3, Dalal Jadayel3, Juergen Dederichs4, Mukul Dalvi4, Benjamin Kramer5On behalf of the INDEED (indacaterol: handling and preference evaluation of the Breezhaler device in COPD study investigators1University of Toronto, Toronto, Canada; 2Spartanburg Medical Research, Spartanburg, SC, United States; 3Novartis Horsham Research Centre, Horsham, West Sussex, UK; 4Novartis Pharma AG, Basel, Switzerland; 5Novartis Pharmaceuticals, East Hanover, NJ, USAAbstract: For optimal efficacy, an inhaler should deliver doses consistently and be easy for patients to use with minimal instruction. The delivery characteristics, patients’ correct use, and preference of two single-dose dry powder inhalers (Breezhaler and HandiHaler were evaluated in two complementary studies. The first study examined aerodynamic particle size distribution, using inhalation profiles of seven patients with moderate to very severe chronic obstructive pulmonary disease (COPD. The second was an open-label, two-period, 7-day crossover study, evaluating use of the inhalers with placebo capsules by 82 patients with mild to severe COPD. Patients’ correct use of the inhalers was assessed after reading written instructions on Day 1, and after training and 7 days of daily use. Patients’ preference was assessed after completion of both study periods. Patient inhalation profiles showed average peak inspiratory flows of 72 L/minute through Breezhaler and 36 L/minute through HandiHaler. For Breezhaler and HandiHaler, fine particle fractions were 27% and 10%, respectively. In the second study, correct use of Breezhaler and HandiHaler was achieved by >77% of patients for any step after 7 days; 61% of patients showed an overall preference for Breezhaler and 31% for HandiHaler (P = 0.01. Breezhaler is a low-resistance inhaler suitable for use by patients with a range of disease severities. Most patients used both inhalers correctly

  4. The dispersion behaviour of dry powder inhalation formulations cannot be assessed at a single inhalation flow rate

    NARCIS (Netherlands)

    Grasmeijer, Floris; de Boer, Anne H.

    2014-01-01

    The dispersion performances of inhalation powders are often tested at only one inhalation flow rate in mechanistic formulation studies. This limited approach is challenged by studies showing that interactions exist between inhalation flow rate and the effects on dispersion performance of several

  5. Forming a single layer of a composite powder based on the Ti-Nb system via selective laser melting (SLM)

    Science.gov (United States)

    Saprykin, A. A.; Sharkeev, Yu P.; Ibragimov, E. A.; Babakova, E. V.; Dudikhin, D. V.

    2016-07-01

    Alloys based on the titanium-niobium system are widely used in implant production. It is conditional, first of all, on the low modulus of elasticity and bio-inert properties of an alloy. These alloys are especially important for tooth replacement and orthopedic surgery. At present alloys based on the titanium-niobium system are produced mainly using conventional metallurgical methods. The further subtractive manufacturing an end product results in a lot of wastes, increasing, therefore, its cost. The alternative of these processes is additive manufacturing. Selective laser melting is a technology, which makes it possible to synthesize products of metal powders and their blends. The point of this technology is laser melting a layer of a powdered material; then a sintered layer is coated with the next layer of powder etc. Complex products and working prototypes are made on the base of this technology. The authors of this paper address to the issue of applying selective laser melting in order to synthesize a binary alloy of a composite powder based on the titanium-niobium system. A set of 10x10 mm samples is made in various process conditions. The samples are made by an experimental selective laser synthesis machine «VARISKAF-100MB». The machine provides adjustment of the following process variables: laser emission power, scanning rate and pitch, temperature of powder pre-heating, thickness of the layer to be sprinkled, and diameter of laser spot focusing. All samples are made in the preliminary vacuumized shielding atmosphere of argon. The porosity and thickness of the sintered layer related to the laser emission power are shown at various scanning rates. It is revealed that scanning rate and laser emission power are adjustable process variables, having the greatest effect on forming the sintered layer.

  6. Analysis of powder and single-crystal electron paramagnetic resonance spectra for manganese(II) protoporphyrin IX myoglobin at various microwave frequencies

    Science.gov (United States)

    Hori, Hiroshi; Ikeda-Saito, Masao; Reed, George H.; Yonetani, Takashi

    Powder and single-crystal electron paramagnetic resonance spectra for manganese(II protoporphyrin IX myoglobin (Mn 2+Mb) were measured at S-, X-, K-, and Q-band microwave frequencies to determine principal g values, hyperfine coupling constants, and zero-field splitting parameters. The effective EPR parameters for the lowest Kramers doublet were found to be g‖ = 1.99, g‖ = 5.90, A‖ = 8.64 mT, and A⊥ = 8.24 mT. Zerofield splitting between the lowest Kramers doublet ( M s = ± {1}/{2}) and the second Kramers doublet ( M s = ± {3}/{2}) was estimated to be 1.39 cm -1. The effective g tensor is approximately axially symmetric. Hyperfine coupling with the 55Mn nucleus was nearly isotropic, but also reflects axial symmetry. The orientation of manganese(II) protoporphyrin plane in single crystals of Mn 2+Mb is nearly identical to that for high-spin iron(III) myoglobin single crystals. The spin-Hamiltonian parameters for Mn 2+Mb are fully consistent with single-crystal or powder spectra obtained at all four microwave frequencies.

  7. The dispersion behaviour of dry powder inhalation formulations cannot be assessed at a single inhalation flow rate.

    Science.gov (United States)

    Grasmeijer, Floris; de Boer, Anne H

    2014-04-25

    The dispersion performances of inhalation powders are often tested at only one inhalation flow rate in mechanistic formulation studies. This limited approach is challenged by studies showing that interactions exist between inhalation flow rate and the effects on dispersion performance of several formulation variables. In this note we explain that such interactions with inhalation flow rate are, in fact, always to be expected. Because these interactions may greatly affect conclusions concerning the effects of formulation variables and their underlying mechanisms, the utility of future dry powder inhalation formulation studies may benefit from an approach in which dispersion performance is by default tested over a range of inhalation flow rates. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2015-10-01

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

  9. Effect of adhesive thickness and surface treatment on shear strength on single lap joint Al/CFRP using adhesive of epoxy/Al fine powder

    Science.gov (United States)

    Diharjo, Kuncoro; Anwar, Miftahul; Tarigan, Roy Aries P.; Rivai, Ahmad

    2016-02-01

    The objective of this study is to investigate the effect of adhesive thickness and surface treatment on the shear strength and failure type characteristic of single lap joint (SLJ) CFRP/Al using adhesive epoxy/Al-fine-powder. The CFRP was produced by using hand layup method for 30% of woven roving carbon fiber (w/w) and the resin used was bisphenolic. The adhesive was prepared using 12.5% of aluminum fine powder (w/w) in the epoxy adhesive. The powder was mixed by using a mixing machine at 60 rpm for 6 minutes, and then it was used to join the Al plate-2024 and CFRP. The start time to pressure for the joint process was 20 minutes after the application of adhesive on the both of adherends. The variables in this research are adhesive thickness (i.e. 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm and 1 mm) and surface treatment of adherends (i.e. acetone, chromate sulphuric acid, caustic etch and tucker's reagent). Before shear testing, all specimens were post-cured at 100 °C for 15 minutes. The result shows that the SLJ has the highest shear strength for 0.4 mm of adhesive thickness. When the adhesive thickness is more than 0.4 mm (0.6-1 mm), the shear strength decreases significantly. It might be caused by the property change of adhesive from ductile to brittle. The acetone surface treatment produces the best bonding between the adhesive and adherends (CFRP and Al-plate 2024), and the highest shear strength is 9.31 MPa. The surface treatment give the humidification effect of adherend surfaces by adhesive. The failure characteristic shows that the mixed failure of light-fiber-tear-failure and cohesive-failure are occurred on the high shear strength of SLJ, and the low shear strength commonly has the adhesive-failure type.

  10. Removal of lead and bisphenol A using magnesium silicate impregnated palm-shell waste powdered activated carbon: Comparative studies on single and binary pollutant adsorption.

    Science.gov (United States)

    Choong, Choe Earn; Ibrahim, Shaliza; Yoon, Yeomin; Jang, Min

    2018-02-01

    In this work, palm shell waste powder activated carbon coated by magnesium silicate (PPAC-MS) were synthesized by the impregnation of magnesium silicate (MgSiO3) using economical material (silicon dioxide powder) via mild hydrothermal approach for the first time. As an effective adsorbent, PPAC-MS simultaneously removes BPA and Pb(II) in single and binary mode. Surprisingly, PPAC-MS exhibited a homogeneous thin plate mesh-like structure, as well as meso- and macropores with a high surface area of 772.1m2g-1. Due to its specific morphological characteristics, PPAC-MS had adsorption capacities of Pb(II) as high as 419.9mgg-1 and 408.8mgg-1 in single mode and binary mode based on Freudliuch isotherm model while those for BPA by PPAC-MS were 168.4mgg-1 and 254.7mgg-1 for single mode and binary modes corresponding to Langmuir isotherm model. Experiment results also indicated that the synergistic removal of BPA occurred because the precipitation process of Pb(II) leads to the co-precipitation of BPA with Pb(OH)2 compound. PPAC-MS showed a good reusability for 5 regeneration cycles using Mg(II) solution followed by thermal treatment. Overall, PPAC-MS has a high potential in the treatment process for wastewater containing both toxic heavy metals and emerging pollutants due to its high sorption capacities and reusability. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

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

  12. Compaction of Titanium Powders

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Improvement in microstructure and superconducting properties of single-filament powder-in-tube MgB2 wires by cold working with a swaging machine

    Science.gov (United States)

    Saito, Yusuke; Murakami, Masato; Matsumoto, Akiyoshi; Kumakura, Hiroaki

    2017-06-01

    We investigated the influence of the mechanical deformation method of wire fabrication on the microstructure and superconducting properties of single-filament in situ powder-in-tube (PIT) MgB2 wires. We employed three deformation methods to fabricate the wires: only swaging, groove rolling + roller drawing, and groove rolling + conventional drawing. We found that cold working by swaging has three advantages over the groove rolling + drawing method: (1) improved uniformity of the MgB2 core along the longitudinal direction; (2) higher mass density of the Mg + B (MgB2) core before (after) heat treatment (HT); and (3) well-developed fiber structures of Mg (MgB2) before (after) HT. These three factors greatly enhanced the critical current density (J c) values of PIT MgB2 wires. The highest J c values were obtained through mechanical deformation by swaging for both pure and carbon-doped wires. A J c value of 3.5 × 104 A cm-2 and an engineering critical current density (J e) of 1.1 × 104 A cm-2 were recorded at 4.2 K and 10 T for a swaged wire of 4.5%-carbon-coated boron powder heat-treated at 600 °C for 1 h.

  14. Crystal structures of eight mono-methyl alkanes (C26–C32 via single-crystal and powder diffraction and DFT-D optimization

    Directory of Open Access Journals (Sweden)

    Lee Brooks

    2015-09-01

    Full Text Available The crystal structures of eight mono-methyl alkanes have been determined from single-crystal or high-resolution powder X-ray diffraction using synchrotron radiation. Mono-methyl alkanes can be found on the cuticles of insects and are believed to act as recognition pheromones in some social species, e.g. ants, wasps etc. The molecules were synthesized as pure S enantiomers and are (S-9-methylpentacosane, C26H54; (S-9-methylheptacosane and (S-11-methylheptacosane, C28H58; (S-7-methylnonacosane, (S-9-methylnonacosane, (S-11-methylnonacosane and (S-13-methylnonacosane, C30H62; and (S-9-methylhentriacontane, C32H66. All crystallize in space group P21. Depending on the position of the methyl group on the carbon chain, two packing schemes are observed, in which the molecules pack together hexagonally as linear rods with terminal and side methyl groups clustering to form distinct motifs. Carbon-chain torsion angles deviate by less than 10° from the fully extended conformation, but with one packing form showing greater curvature than the other near the position of the methyl side group. The crystal structures are optimized by dispersion-corrected DFT calculations, because of the difficulties in refining accurate structural parameters from powder diffraction data from relatively poorly crystalline materials.

  15. Pressure-induced phase transitions in organic molecular crystals: a combination of x-ray single-crystal and powder diffraction, raman and IR-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Boldyreva, E V; Goryainov, S V; Seryotkin, Y V; Kolesnik, E N; Shakhtshneider, T P; Ivashevskaya, S N; Drebushchak, T N [Research and Education Center ' Molecular Design and Ecologically Safe Technologies' , REC-008, Novosibirsk State University (Russian Federation); Sowa, H [Goettingen University (Germany); Ahsbahs, H; Chernyshev, V V [Marburg University (Germany); Dmitriev, V P [Swiss-Norwegian Beamline ESRF, Grenoble (France)], E-mail: boldyrev@nsu.ru

    2008-07-15

    The contribution summarizes the results of recent studies of phase transitions induced by high pressure in a number of molecular organic crystals, such as polymorphs of paracetamol, chlorpropamide, polymorphs of glycine, L- and DL-serine, {beta}-alanine. The main attention is paid to the following topics: (1) Reversible / irreversible transformations; (2) Different behavior of single crystals / powders; (3) The role of pressure-transmitting liquid; (4) The role of the kinetic factors: phase transitions on decompression, or after a long storage at a selected pressure; (5) Isosymmetric phase transitions; (6) The role of the changes in the hydrogen bond networks / intramolecular conformational changes in the phase transitions; (7) Superstructures / nanostructures formed as a result of pressure-induced phase transitions.

  16. Ease-of-use preference for the ELLIPTA® dry powder inhaler over a commonly used single-dose capsule dry powder inhaler by inhalation device-naïve Japanese volunteers aged 40 years or older

    Directory of Open Access Journals (Sweden)

    Komase Y

    2014-12-01

    Full Text Available Yuko Komase,1 Akimoto Asako,2 Akihiro Kobayashi,3 Raj Sharma4 1Department of Respiratory Internal Medicine, St Marianna University School of Medicine, Yokohama City Seibu Hospital, Yokohama, Kanagawa, Japan; 2MA Respiratory Department, Development and Medical Affairs Unit, GlaxoSmithKline KK, Tokyo, Japan; 3Biomedical Data Sciences Department, GlaxoSmithKline KK, Tokyo, Japan; 4Global Respiratory Franchise Medical Department, GSK, Stockley Park, UK Background: In patients receiving inhaled medication, dissatisfaction with and difficulty in using the inhaler can affect treatment adherence. The incidence of handling errors is typically higher in the elderly than in younger people. The aim of the study was to assess inhaler preference for and handling errors with the ELLIPTA® dry powder inhaler (DPI, (GSK, compared with the established BREEZHALER™, a single-dose capsule DPI (Novartis, in inhalation device-naïve Japanese volunteers aged ≥40 years. Methods: In this open-label, nondrug interventional, crossover DPI preference study comparing the ELLIPTA DPI and BREEZHALER, 150 subjects were randomized to handle the ELLIPTA or BREEZHALER DPIs until the point of inhalation, without receiving verbal or demonstrative instruction (first attempt. Subjects then crossed over to the other inhaler. Preference was assessed using a self-completed questionnaire. Inhaler handling was assessed by a trained assessor using a checklist. Subjects did not inhale any medication in the study, so efficacy and safety were not measured. Results: The ELLIPTA DPI was preferred to the BREEZHALER by 89% of subjects (odds ratio [OR] 70.14, 95% confidence interval [CI] 33.69–146.01; P-value not applicable for this inhaler for ease of use, by 63% of subjects (OR 2.98, CI 1.87–4.77; P<0.0001 for ease of determining the number of doses remaining in the inhaler, by 91% for number of steps required, and by 93% for time needed for handling the inhaler. The BREEZHALER was

  17. Solution combustion synthesis of strontium aluminate, SrAl2O4, powders: single-fuel versus fuel-mixture approach.

    Science.gov (United States)

    Ianoş, Robert; Istratie, Roxana; Păcurariu, Cornelia; Lazău, Radu

    2016-01-14

    The solution combustion synthesis of strontium aluminate, SrAl2O4, via the classic single-fuel approach and the modern fuel-mixture approach was investigated in relation to the synthesis conditions, powder properties and thermodynamic aspects. The single-fuel approach (urea or glycine) did not yield SrAl2O4 directly from the combustion reaction. The absence of SrAl2O4 was explained by the low amount of energy released during the combustion process, in spite of the highly negative values of the standard enthalpy of reaction and standard Gibbs free energy. In the case of single-fuel recipes, the maximum combustion temperatures measured by thermal imaging (482 °C - urea, 941 °C - glycine) were much lower than the calculated adiabatic temperatures (1864 °C - urea, 2147 °C - glycine). The fuel-mixture approach (urea and glycine) clearly represented a better option, since (α,β)-SrAl2O4 resulted directly from the combustion reaction. The maximum combustion temperature measured in the case of a urea and glycine fuel mixture was the highest one (1559 °C), which was relatively close to the calculated adiabatic temperature (1930 °C). The addition of a small amount of flux, such as H3BO3, enabled the formation of pure α-SrAl2O4 directly from the combustion reaction.

  18. Ease-of-use preference for the ELLIPTA® dry powder inhaler over a commonly used single-dose capsule dry powder inhaler by inhalation device-naïve Japanese volunteers aged 40 years or older.

    Science.gov (United States)

    Komase, Yuko; Asako, Akimoto; Kobayashi, Akihiro; Sharma, Raj

    2014-01-01

    In patients receiving inhaled medication, dissatisfaction with and difficulty in using the inhaler can affect treatment adherence. The incidence of handling errors is typically higher in the elderly than in younger people. The aim of the study was to assess inhaler preference for and handling errors with the ELLIPTA® dry powder inhaler (DPI), (GSK), compared with the established BREEZHALER™, a single-dose capsule DPI (Novartis), in inhalation device-naïve Japanese volunteers aged ≥40 years. In this open-label, nondrug interventional, crossover DPI preference study comparing the ELLIPTA DPI and BREEZHALER, 150 subjects were randomized to handle the ELLIPTA or BREEZHALER DPIs until the point of inhalation, without receiving verbal or demonstrative instruction (first attempt). Subjects then crossed over to the other inhaler. Preference was assessed using a self-completed questionnaire. Inhaler handling was assessed by a trained assessor using a checklist. Subjects did not inhale any medication in the study, so efficacy and safety were not measured. The ELLIPTA DPI was preferred to the BREEZHALER by 89% of subjects (odds ratio [OR] 70.14, 95% confidence interval [CI] 33.69-146.01; P-value not applicable for this inhaler) for ease of use, by 63% of subjects (OR 2.98, CI 1.87-4.77; PELLIPTA DPI for comfort of the mouthpiece by 64% of subjects (OR 3.16, CI 1.97-5.06; PELLIPTA and 68% with BREEZHALER; differences in incidence were generally similar when analyzed by age (ELLIPTA DPI is preferred to an established alternative based on its ease-of-use features and is associated with fewer handling errors.

  19. Insight into Flufenamic Acid Cocrystal Dissolution in the Presence of a Polymer in Solution: from Single Crystal to Powder Dissolution.

    Science.gov (United States)

    Guo, Minshan; Wang, Ke; Qiao, Ning; Fábián, László; Sadiq, Ghazala; Li, Mingzhong

    2017-11-10

    Effects of three polymers, polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and copolymer of vinylpyrrolidone/vinyl acetate (PVP-VA), on the dissolution behavior of the cocrystals of flufenamic acid with theophylline (FFA-TP CO) and nicotinamide (FFA-NIC CO) were investigated at multiple length scales. At the molecular level, the interactions of crystal surfaces with a polymer were analyzed by observing etching pattern changes using atomic force microscopy. At the macroscopic scale, dissolution rates of particular faces of a single crystal were determined by measurement of the physical retreat velocities of the faces using optical light microscopy. In the bulk experiments, the FFA concentration in a dissolution medium in the absence or presence of a polymer was measured under both sink and nonsink conditions. It has been found that the dissolution mechanisms of FFA-TP CO are controlled by the defect sites of the crystal surface and by precipitation of the parent drug FFA as individual crystals in the bulk fluid. In contrast, the dissolution mechanisms of FFA-NIC CO are controlled by surface layer removal and by a surface precipitation mechanism, where the parent drug FFA precipitates directly onto the surface of the dissolving cocrystals. Through controlling the dissolution environment by predissolving a polymer, PVP or PVP-VA, which can interact with the crystal surface to alter its dissolution properties, improved solubility, and dissolution rates of FFA-TP CO and FFA-NIC CO have been demonstrated.

  20. Powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Hart, M.

    1995-12-31

    the importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940`s, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments.

  1. Pharmacokinetics, Safety, and Tolerability of Amygdalin and Paeoniflorin After Single and Multiple Intravenous Infusions of Huoxue-Tongluo Lyophilized Powder for Injection in Healthy Chinese Volunteers.

    Science.gov (United States)

    Li, Xiaobing; Shi, Fuguo; Zhang, Run; Sun, Chenglong; Gong, Chuting; Jian, Lingyan; Ding, Li

    2016-02-01

    Huoxue-Tongluo lyophilized powder for injection (HTLPI), a traditional Chinese medicine preparation, is a compound of Persicae semen and Paeoniae Radix Rubra that is used mainly for treating blood-stasis obstruction syndrome in the acute stage of cerebral ischemic stroke. Amygdalin (AD) and paeoniflorin (PF) are 2 typical bioactive components in HTLPI and were selected as indicators for this pharmacokinetic study of HTLPI. The objective of this study was to investigate the safety profile, tolerability, and pharmacokinetic properties of AD and PF after single and multiple intravenous infusions of HTLPI in healthy Chinese volunteers. Twenty-one healthy Chinese subjects were recruited for this open-label, single ascending-dose (3, 6, and 9 g) and multiple-dose (6 g, once daily) study. Safety profile was assessed by adverse events and physical examination throughout the study. Serial plasma and urine samples were analyzed by HPLC-MS/MS. Pharmacokinetic parameters of AD and PF were calculated using noncompartmental analysis. In the single-dose phase of the study, the mean maximum plasma concentration and the mean area under the plasma concentration-time curve of AD and PF increased proportionally with each dose escalation. In the multiple-dose phase, the steady state was achieved by day 4 after multiple-dose administration of 6 g HTLPI. Mean pharmacokinetic parameters achieved on day 1 were similar to those on day 7. No significant accumulation was observed after repeat doses of 6 g HTLPI. Approximately 79.6% of the administered AD and 48.4% of the administered PF were excreted unchanged in urine within 24 hours. No serious adverse events were observed during the entire study. The pharmacokinetic properties of AD and PF were linear after a single intravenous infusion of HTLPI in the dose range of 3-9 g. No systemic accumulation was observed with repeat doses of HTLPI. Sex had no significant effect on the pharmacokinetic properties of AD and PF. Intravenous infusion of

  2. (YSZ) powders

    Indian Academy of Sciences (India)

    Unknown

    XRD pattern for YSZ gel calcined at 900°C. Figure 3. Particle size distribution of the dry and wet ground slurries (20 vol.% solid content at a pH of 3). A. powder dry ground for 1 h; B, C, D, E. wet ground for 1, 2, 4, 10 h, res- pectively. Figure 4. Zeta-potential variation with pH for aqueous sus- pensions of 900°C calcined YSZ ...

  3. Talcum powder poisoning

    Science.gov (United States)

    ... better the chance for recovery. Breathing in talcum powder can lead to very serious lung problems, even death. Use caution when using talcum powder on babies. Talc-free baby powder products are ...

  4. A breath actuated dry powder inhaler

    NARCIS (Netherlands)

    de Boer, Anne; Frijlink, Henderik W.; Hagedoorn, Paul

    2015-01-01

    A breath actuated dry powder inhaler with a single air circulation chamber for de-agglomeration of entrained powdered medicament using the energy of the inspiratory air stream. The chamber has a substantially polygonal sidewall, a plurality of air supply channels entering the chamber substantially

  5. Resin-Powder Dispenser

    Science.gov (United States)

    Standfield, Clarence E.

    1994-01-01

    Resin-powder dispenser used at NASA's Langley Research Center for processing of composite-material prepregs. Dispenser evenly distributes powder (resin polymer and other matrix materials in powder form) onto wet uncured prepregs. Provides versatility in distribution of solid resin in prepreg operation. Used wherever there is requirement for even, continuous distribution of small amount of powder.

  6. The development of a single-use, capsule-free multi-breath tobramycin dry powder inhaler for the treatment of cystic fibrosis.

    Science.gov (United States)

    Zhu, Bing; Padroni, Matteo; Colombo, Gaia; Phillips, Gary; Crapper, John; Young, Paul M; Traini, Daniela

    2016-12-05

    The aerosol performance and delivery characteristics of tobramycin for the treatment of respiratory infection were evaluated using the Orbital™, a multi-breath, high dose, dry powder inhaler (DPI). Micronised tobramycin was prepared and tested in the Orbital and in the commercially available TOBI Podhaler (Novartis AG). Furthermore, the TOBI Podhaler formulation containing tobramycin as Pulmospheres was tested in both the commercial Podhaler device (T-326) and Orbital for comparison. By varying the puck geometry of the Orbital, it was possible to deliver equivalent doses of micronised tobramycin (114.09±5.86mg) to that of the Podhaler Pulmosphere product (116.01±2.59mg) over 4 sequential simulated breaths (60Lmin(-1) for 4s) without the need for multiple capsules. In general, the aerosol performance of the micronised tobramycin from the Orbital was higher than the T-326 Podhaler device, with fine particle fraction (FPF) of 44.99%±1.09% and 37.03%±0.86%, respectively. When testing the Pulmosphere powder in the two devices, the T-326 had marginally better performance with a FPF of 68.77%±2.10% compared to 61.30%±3.45%. This is to be expected since the TOBI Podhaler and Pulmosphere are an optimised powder and device combination. The Orbital was shown to be capable of delivering high efficiency, high dose antibiotic therapy for inhalation without the need for the use of multiple capsules as used in current devices. This approach may pave the way for a number of antibiotic therapies and medicaments where high dose respiratory deposition is required. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Pharmacokinetic and bioequivalence comparison of a single 100-mg dose of cefteram pivoxil powder suspension and tablet formulations: a randomized-sequence, open-label, two-period crossover study in healthy Chinese adult male volunteers.

    Science.gov (United States)

    Zou, Jianjun; Di, Bin; Wu, Chun Yong; Hu, Qin; Li, Jian Hua; Zhu, Yubing; Fan, Hongwei; Xiao, DaWei; Wang, Guang Ji

    2008-04-01

    Cefteram pivoxil (CFTM-PI) is an oral antibiotic available in powder suspension and tablet formulations indicated in China for the treatment of bacterial infections. Although these 2 formulations are marketed in China, published information regarding their pharmacokinetics and bioequivalence in the Chinese population is not available. The aim of this study was to compare the pharmacokinetics and bioequivalence of the powder suspension (test) and tablet (reference) formulations of CFTM-PI 100 mg available in China. This single-dose, randomized-sequence, open-label, 2-period crossover study was performed at the Nanjing First Hospital of Nanjing Medical University. Eligible subjects were healthy male volunteers who were randomly assigned at a 1:1 ratio to receive a single 100-mg dose of the test or reference formulation, followed by a 1-week washout period and administration of the alternate formulation. The study drugs were administered after a 12-hour overnight fast. Plasma was assayed using a high-performance liquid chromatography method. For analysis of pharmacokinetic properties, including C(max), AUC from time 0 (baseline) to 6 hours (AUC(0-6)), and AUC from baseline to infinity (AUC(0-infinity)), blood samples were obtained at intervals over the 6-hour period after study drug administration. The formulations were considered bioequivalent if the log-transformed ratios of C(max) and AUC were within the predetermined equivalence range (80%-125%) as established by the US Food and Drug Administration (FDA). Tolerability was assessed by monitoring vital signs and laboratory tests (hematology, blood biochemistry, hepatic function, and urinalysis), and by questioning subjects about adverse events (AEs). Twenty-four Chinese male subjects (mean [range] age,24.2 [23-32] years;weight,64.3 [58-67] kg; height, 172 [167-185] cm) enrolled; all completed the study. No period or sequence effect was observed. The 90% CIs for the log-transformed ratios of C(max), AUC(0-6;), and

  8. SOVIET ABSTRACTS ON POWDER METALLURGY

    Science.gov (United States)

    CERMETS, * POWDER METALLURGY , ABSTRACTS, CERAMIC MATERIALS, HEAT RESISTANT ALLOYS, INDUSTRIAL PRODUCTION, MECHANICAL PROPERTIES, PIEZOELECTRIC CRYSTALS, POLARIZATION, POROUS METALS, POWDER ALLOYS, POWDER METALS, SINTERING.

  9. Aluminum powder metallurgy processing

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, J.F.

    1999-02-12

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

  10. Impact of Moringa oleifera lam. Leaf powder supplementation versus nutritional counseling on the body mass index and immune response of HIV patients on antiretroviral therapy: a single-blind randomized control trial.

    Science.gov (United States)

    Tshingani, Koy; Donnen, Philippe; Mukumbi, Henri; Duez, Pierre; Dramaix-Wilmet, Michèle

    2017-08-22

    To achieve effective antiretroviral therapy (ART) outcomes, adherence to an antiretroviral regimen and a good immunometabolic response are essential. Food insecurity can act as a real barrier to adherence to both of these factors. Many people living with human immunodeficiency virus (PLHIV) treated with ART in the Democratic Republic of the Congo (DRC) are faced with nutritional challenges. A significant proportion are affected by under nutrition, which frequently leads to therapeutic failure. Some HIV care facilities recommend supplementation with Moringa oleifera (M.O.) Lam. leaf powder to combat marginal and major nutritional deficiencies. This study aims to assess the impact of M.O. Lam. leaf powder supplementation compared to nutritional counseling on the nutritional and immune status of PLHIV treated with ART. A single-blind randomized control trial was carried out from May to September 2013 at an outpatient clinic for HIV-infected patients in Kinshasa (DRC). Sixty adult patients who were at stable HIV/AIDS clinical staging 2, 3 or 4 according to the World Health Organization (WHO), and were undergoing ART were recruited. After random allocation, 30 patients in the Moringa intervention group (MG) received the M.O. Lam. leaf powder daily over 6 months, and 30 in the control group (CG) received nutritional counseling over the same period. Changes in the body mass index (BMI) were measured monthly and biological parameters were measured upon admission and at the end of the study for the patients in both groups. The two study groups were similar in terms of long-term nutritional exposure, sociodemographic, socioeconomic, clinical, and biological features. At 6 months follow-up, patients in the MG exhibited a significantly greater increase in BMI and albumin levels than those in the CG. The interaction between the sociodemographic, clinical, and biological characteristics of patients in the two groups was not significant, with the exception of professional

  11. Preparation and Evaluation of Herbal Shampoo Powder

    Science.gov (United States)

    Dubey, Sachin; Nema, Neelesh; Nayak, S.

    2004-01-01

    Two preparations of herbal shampoo powder were formulated using some common traditional drugs used by folk and traditional people of Bundelkhand region (M.P) India, for hair care. The preparations were formulated using bahera, amla, neem tulsi, shikakai henna & brahmi evaluated for organoleptic, powder charecterestics, foam test and physical evaluation. As the selected drugs being used since long time as single drug or in combination, present investigations will further help to establish a standard formulation and evaluation parameters, which will certainly help in the standardization for quality and purity of such type of herbal powder shampoos. PMID:22557149

  12. A Comprehensive Review of Black Powder

    Science.gov (United States)

    1985-01-01

    second role is to prevent absorption of water. From high speed cinematography of a single burning grain, it appears that the coating acts as an...graphite film thickness. C. Internal Structure of Black Powder S.E.M. microphotographs of class one black powder were obtained by first cleaving the...ground in the Indiana pilot plant jet-mill. They were burned in air at atmospheric pressure and photographed by cinematography at 2000 frames per

  13. Additive Technologies Based on Composite Powder Nanomaterials

    Science.gov (United States)

    Gorynin, I. V.; Oryshchenko, A. S.; Malyshevskii, V. A.; Farmakovskii, B. V.; Kuznetsov, P. A.

    2015-01-01

    The possibilities of application of promising adaptive technologies of bulk laser deposition and selective laser sintering in machine building with the aim of creation of complex-configuration parts and reconditioning of worn components of various-purpose articles from metallic powder materials are considered. The possibilities of the production chain from making of metallic powders to creation of ready coatings and articles on the base of a single unit are described.

  14. Determination of the hydrogen positions in the novel barium boroarsenate Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] by combined single crystal X-ray and powder neutron investigations

    Energy Technology Data Exchange (ETDEWEB)

    Lieb, Alexandra [School of Chemistry, University of Southampton (United Kingdom); Fakultaet fuer Verfahrens- und Systemtechnik, Lehrstuhl fuer Technische Chemie, Otto-von-Guericke-Universitaet, Magdeburg (Germany); Weller, Mark T. [School of Chemistry, University of Southampton (United Kingdom); Department of Chemistry, University of Bath (United Kingdom)

    2017-11-17

    The boroarsenate Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was obtained by the reaction of NH{sub 4}H{sub 2}AsO{sub 4}, B(OH){sub 3} and BaBr{sub 2}.2H{sub 2}O in the melt. Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was obtained as thin colorless needles, together with spherical crystals of BAsO{sub 4} as by-product, grown on a pellet of Ba[BAsO{sub 5}]. The products could be separated mechanically. For neutron scattering experiments a sample was prepared with {sup 11}B(OH){sub 3} as a starting material. The crystal structure of Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was determined by single-crystal X-ray diffraction and exhibits a layer structure with an unprecedented layer topology. The exact positions of the hydrogen atoms were determined using combined single-crystal X-ray and powder neutron diffraction investigations. Ba[B{sub 2}As{sub 2}O{sub 8}(OH){sub 2}] was further characterized by IR spectroscopy and EDX analysis. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Titanium Powder Metallurgy Forgings.

    Science.gov (United States)

    TITANIUM ALLOYS, *FORGING), (* POWDER METALLURGY , TITANIUM ALLOYS), ENGINE COMPONENTS, INLET GUIDE VANES, JET ENGINES, RINGS, AIRFRAMES, ANCHORS(STRUCTURAL), COLD WORKING, SINTERING, MECHANICAL PROPERTIES

  16. Dustiness of fine and nanoscale powders.

    Science.gov (United States)

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

    2013-03-01

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

  17. Powder Diffraction: By Decades

    Science.gov (United States)

    David, William I. F.

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

  18. Laser powder microdeposition of CP2 Titanium

    Energy Technology Data Exchange (ETDEWEB)

    Meacock, C. [Departamento de Engenharia de Materiais, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)], E-mail: rui.vilar@ist.utl.pt; Vilar, R. [Departamento de Engenharia de Materiais, Instituto Superior Tecnico, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2008-07-01

    Laser powder microdeposition (LPMD) uses a finely focused laser beam to generate a minute meltpool on the surface of a metallic substrate into which metallic powder is blown. The laser/powder interaction zone is scanned over the substrate and molten material re-solidifies leaving microscale tracks of deposited material. The ability to deposit material on this scale opens up the possibilities of the alteration of the surface properties of small metallic components, the repair of fine damage such as fractures and wear and the fabrication of small components that require high dimensional accuracy such as dental and maxillofacial implants. In this paper, a novel Laser powder microdeposition system is described whereby the powder is fed via a fine capillary. The system was used to deposit single tracks, thin walls and a solid part of grade 2 commercially pure (CP2) Titanium, a material suitable for the fabrication of dental implants. The geometry of both single tracks and thin walls of CP2 Titanium deposited by LPMD can be controlled by variation of laser power and scanning speed. The process can be used to produce porosity free thin wall structures with widths lower than 450 {mu}m and with a surface roughness lower than 20 {mu}m (Ra)

  19. Biaxially textured articles formed by powder metallurgy

    Science.gov (United States)

    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} orientation texture; and further having a Curie temperature less than that of pure Ni.

  20. Development and directions of powder diffraction on proteins

    Energy Technology Data Exchange (ETDEWEB)

    Von Dreele, R.B.; Besnard, C.; Basso, S.; Camus, F.; Pattison, P.; Schiltz, M.; Wright, J.P.; Margiolaki, R.; Fitch, A.N.; Fox, G.C.; Prugoveeki, S.; Beckers, D.; Helliwell, J.R.; Helliwell, M.; Jones, R.H.; Roberts, M.A.; Miura, K.; Kahn, R.; Giacovazzo, C.; Altomare, A.; Caliandro, R.; Camalli, M.; Cuocci, C.; Moliterni, A.G.G.; Rizzi, R.; Hinrichsen, B.; Kern, A.; Coelho, A.A.; Degen, T.; Kokkinidis, M.; Fadouloglou, V.; Gazi, A.; Panopoulos, N.; Pinotsis, N.; Wilmanns, M.; Norrman, M.; Schluckebier, G.; Prugoveeki, B.; Dilovic, J.; Matkovic-Calogovic, D.; Bill, David; Markvardsen, A.; Grosse-Kunstleve, R.; Rius, J.; Glykos Nicholas, M.; Murshudov, G.N

    2007-07-01

    X-ray diffraction is one of the most important method for obtaining information about the structure of proteins and thereby for gaining insight into fundamental biological and biochemical mechanisms. This seminar was dedicated to X-ray powder diffraction and was organized around 6 sessions: 1) what can powder diffraction do for proteins?, 2) adapting experimentally to proteins, 3) interpreting powder data, 4) the world of protein crystallography, 5) advancing methods for powder data analysis, and 6) transferable methods from single crystals. This document gathers the abstracts of the 23 papers presented. (A.C.)

  1. Inhaled dry powder formulations for treating tuberculosis.

    Science.gov (United States)

    Das, Shyamal; Tucker, Ian; Stewart, Peter

    2015-01-01

    Tuberculosis is the second leading cause of death from infectious diseases. Although antitubercular drugs have been traditionally administered orally, there is a growing interest in delivering drugs via the pulmonary route using nebulisers or dry powder inhalers. Drugs in dry powder inhalers (DPI) are stable and DPI are user-friendly compared to nebulisation which is time consuming, inconvenient and inefficient and requires special equipment. For tuberculosis treatment, drugs should target alveolar macrophages that harbour microorganisms and/or maintain high drug concentration at the infection site in the lung. Drug particles include micro-particles or nanoparticles. Powders can be engineered by micronisation, crystallisation, spray drying, freeze drying and particle coating approaches. The formulation may contain single or combination drugs. This paper will provide an update on current status of TB, its pathogenesis, current treatment strategies, shortcomings of current oral or parenteral delivery strategies, pulmonary delivery devices, advantages of pulmonary delivery of powder formulations, formulation approaches and pharmacokinetic studies of pulmonary delivery of powders for inhalation.

  2. Demystifying Mystery Powders.

    Science.gov (United States)

    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)

  3. Functionalized hyperbranched polyethylene powder supports.

    Science.gov (United States)

    Bergbreiter, D E; Tao, G; Kippenberger, A M

    2000-09-07

    [reaction: see text] Polyethylene powders with useful loadings of functional groups are accessible by hyperbranched grafting chemistry. Using a 200 microm diameter high-density powder, loadings of up to 0.4 mmol/g of CO(2)H groups are attained. The carboxylic acid groups in the resulting powders can be further functionalized covalently or ionically and resulting powders have the physical durability and solvent resistance associated with polyethylene itself.

  4. Powder diffraction at ALBA synchrotron

    OpenAIRE

    Aranda, Miguel A. G.

    2017-01-01

    This talk is devoted to explain the uses of powder diffraction at MSPD (material science and powder diffraction) of ALBA synchrotron light source. General characteristics of the beamline are: Station 1 - High Pressure Diffraction on powders with diamond anvil cell (DAC) and CCD detector. Microdiffraction; and Station 2 - High Resolution Powder Diffraction with Multicrystal- and Silicon-Strip detector. Energy Range: 8-50keV; Typical beam size: 4x1mm; all typical sample geometries possible: cap...

  5. Advanced powder processing

    Energy Technology Data Exchange (ETDEWEB)

    Janney, M.A. [Oak Ridge National Lab., TN (United States)

    1997-04-01

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

  6. Dispersing powders in liquids

    CERN Document Server

    Nelson, RD

    1988-01-01

    This book provides powder technologists with laboratory procedures for selecting dispersing agents and preparing stable dispersions that can then be used in particle size characterization instruments. Its broader goal is to introduce industrial chemists and engineers to the phenomena, terminology, physical principles, and chemical considerations involved in preparing and handling dispersions on a commercial scale. The book introduces novices to: - industrial problems due to improper degree of dispersion; - the nomenclature used in describing particles; - the basic physica

  7. Uniting Electron Crystallography and Powder Diffraction

    CERN Document Server

    Shankland, Kenneth; Meshi, Louisa; Avilov, Anatoly; David, William

    2012-01-01

    The polycrystalline and nanocrystalline states play an increasingly important role in exploiting the properties of materials, encompassing applications as diverse as pharmaceuticals, catalysts, solar cells and energy storage. A knowledge of the three-dimensional atomic and molecular structure of materials is essential for understanding and controlling their properties, yet traditional single-crystal X-ray diffraction methods lose their power when only polycrystalline and nanocrystalline samples are available. It is here that powder diffraction and single-crystal electron diffraction techniques take over, substantially extending the range of applicability of the crystallographic principles of structure determination.  This volume, a collection of teaching contributions presented at the Crystallographic Course in Erice in 2011, clearly describes the fundamentals and the state-of-the-art of powder diffraction and electron diffraction methods in materials characterisation, encompassing a diverse range of discipl...

  8. Sintering of HDH Ti Powder

    Directory of Open Access Journals (Sweden)

    Kováčik Jaroslav

    2014-12-01

    Full Text Available Titanium powders prepared by hydro-dehydration process (HDH powder were pressure less sintered in vacuum oven at different temperatures, time and green density. The sintering properties of powders of two particle sizes - 30 and 150 microns were investigated. The usual powder metallurgical (PM results were observed, i.e., decreasing final porosity with increasing sintering temperature and time at constant heating rate. Higher green density leading to higher final density for both powder sizes was also observed. The obtained results will be used as comparative material for future sintering experiments of Ti based composites.

  9. Powder Production and Particle Engineering for Dry Powder Inhaler Formulations.

    Science.gov (United States)

    Lin, Yu-Wei; Wong, Jennifer; Qu, Li; Chan, Hak-Kim; Zhou, Qi Tony

    2015-01-01

    Dry powder inhalers have become increasingly attractive for pulmonary delivery of locally and systemically effective medications. In comparison to the liquid counterparts, such as nebulisation and pressurised metered dose inhalers, the powder form generally offers better chemical stability, improved portability and potentially superior patient adherence. Currently, the aerosol performance between dry powder inhalers varies to a large extent due to differences in the design of inhaler device and formulation. The particulate properties have a significant influence on the inter-particle interactions, which impacts on the aerosolisation of the inhaled powder. In this review, critical particulate properties that affect aerosol performance are discussed. Recent advances in powder production and particle engineering techniques are also assessed, aiming to develop new inhaled powder formulations or improve the aerosolisation efficiency of existing products.

  10. Characterization of Ce0.9Gd0.1O1.95 powders synthesized by spray drying

    DEFF Research Database (Denmark)

    Blennow Tullmar, Peter; Chen, Weiwu; Lundberg, Mats

    2009-01-01

    Ce0.9Gd0.1O1.95 powders were synthesized by spray drying and successive calcinations. The phase purity, BET surface area, and particle morphology of as-sprayed and calcined powders were characterized. After calcination above 300 °C, the powders were single phase and showed a BET surface area of 68...

  11. Indigenous tooth powders = Covert lead poisoning?

    National Research Council Canada - National Science Library

    Hegde, Sapna; Shubha, A; Rao, B

    2013-01-01

    .../almond shell, coconut shell and its sheath, wood, coal and other powders (sand, common salt-powder and crystalline, brick and tile powder, tobacco, areca nut). [4] In addition, a variety of indigenous tooth powders are marketed which are very popular with the local people. Many of these age-old formulations of tooth powders may contain ha...

  12. Method of manufacturing powder particles

    NARCIS (Netherlands)

    Borra, J.P.D.

    2002-01-01

    The invention relates to a method of manufacturing a dry powder particle, preferably using electro-hydrodynamic spraying, wherein two oppositely charged aerosol streams are contacted. The invention allows for the manufacture of powders having various, controllable compositions and shapes. In

  13. A review on flow characterization methods for cereal grain-based powders.

    Science.gov (United States)

    Ambrose, R P Kingsly; Jan, Shumaila; Siliveru, Kaliramesh

    2016-01-30

    Flow difficulties during handling, storage, and processing are common in cereal grain-based powder industries. The many studies that focus on the flow properties of powders can be classified as flow indicators, shear properties, and dynamic flow properties. The non-uniformity of physical and chemical characteristics of the individual particles that make up the bulk solid of cereal grain-based powders adds complexity to the characterization of flow behavior. Even so, knowledge of flow behavior is critical to the design of productive and cost-effective equipment for handling and processing of these powders. Because many factors influence flow, a single property/index value may not satisfactorily quantify the flow or no-flow of powders. For powders of biological origin, chemical composition and environmental factors such as temperature and relative humidity complicate flow characterization. This review focuses on the specific flow characteristics that directly affect powder flow during handling, processing, and storage. © 2015 Society of Chemical Industry.

  14. Effect of packing density on shock consolidation of diamond powders

    Science.gov (United States)

    Joshi, V. S.; Grebe, H. A.; Thadhani, N. N.; Iqbal, Z.

    1994-07-01

    Diamond powders of different types and particle size distribution were shock consolidated using a plate impact shock recovery system at 1.6 to 2.2 km/s. Single-piece diamond compacts (approximately 12 mm diameter and 2-4 mm thickness) with relative densities in the range of 88-94% of Theoretical Maximum Density (TMD) and less than 5% non-diamond phase, were produced. While the effects of several different variables, e.g., powder pre-treatment, particle size and distribution, and impact conditions, were explored, it was established that the initial green-powder-compact density was the most important variable controlling the densification of diamond powders. In this paper, we will present results of some of the consolidation experiments and the role of initial green density in controlling the final compact density and microstructure.

  15. Powder-Bed Stabilization for Powder-Based Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Andrea Zocca

    2014-06-01

    Full Text Available The most successful additive manufacturing (AM technologies are based on thelayer-by-layer depositionof a flowable powder. Although considered as the third industrial revolution, one factor still limiting these processes to become completely autonomous is the often necessary build-up of support structures. Besides the prevention of lateral shifts of the part during the deposition of layers, the support assures quality and stability to the built process. The loose powder itself surrounding the built object, or so-called powder-bed, does not provide this sustenance in most existent technology available. Here we present a simple but effective and economical method for stabilizing the powder-bed, preventing distortions in the geometry with no need for support structures. This effect, achieved by applying an air flow through the powder-bed, is enabling an entirely autonomous generation of parts and is a major contribution to all powder-based additive manufacturing technologies. Moreover, it makes powder-based AM independent of gravitational forces, which will facilitate crafting items in space from a variety of powdery materials.

  16. Characterization of Cu{sub 6}Sn{sub 5} intermetallic powders produced by water atomization and powder heat treatment

    Energy Technology Data Exchange (ETDEWEB)

    Tongsri, Ruangdaj, E-mail: ruangdt@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Yotkaew, Thanyaporn, E-mail: thanyy@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Krataitong, Rungtip, E-mail: rungtipk@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Wila, Pongsak, E-mail: pongsakw@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Sir-on, Autcharaporn, E-mail: autchars@mtec.or.th [Materials Characterization Research Unit (MCRU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Muthitamongkol, Pennapa, E-mail: pennapm@mtec.or.th [Materials Characterization Research Unit (MCRU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand); Tosangthum, Nattaya, E-mail: nattayt@mtec.or.th [Powder Metallurgy Research and Development Unit (PM-RDU), National Metal and Materials Technology Center, 114 Paholyothin, Klong 1, Klong Luang, Pathum Thani 12120 (Thailand)

    2013-12-15

    Since the Cu{sub 6}Sn{sub 5} intermetallic shows its importance in industrial applications, the Cu{sub 6}Sn{sub 5} intermetallic-containing powders, produced by a powder processing route with a high production rate, were characterized. The route consisted of water atomization of an alloy melt (Cu–61 wt.% Sn) and subsequent heat treatment of the water-atomized powders. Characterization of the water-atomized powders and their heated forms was conducted by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Fine water-atomized powder microstructures consisted of primary hexagonal η-Cu{sub 6.25}Sn{sub 5} dendrites coexisting with interdendritic η-Cu{sub 6.25}Sn{sub 5} + β-Sn eutectic. Solidification of fine melt droplets was governed by surface nucleation and growth of the primary hexagonal η-Cu{sub 6.25}Sn{sub 5} dendrites followed by η-Cu{sub 6.25}Sn{sub 5} + β-Sn eutectic solidification of the remnant liquid. In coarse melt droplets, nucleation and growth of primary ε-Cu{sub 3}Sn dendrites were followed by peritectic reaction (ε-Cu{sub 3}Sn + liquid → η-Cu{sub 6.25}Sn{sub 5}) or direct crystallization of η-Cu{sub 6.25}Sn{sub 5} phase from the undercooled melt. Finally, the η-Cu{sub 6.25}Sn{sub 5} + β-Sn eutectic solidification of the remnant liquid occurred. Heating of the water-atomized powders at different temperatures resulted in microstructural homogenization. The water-atomized powders with mixed phases were transformed to powders with single monoclinic ή-Cu{sub 6}Sn{sub 5} phase. - Highlights: • The Cu{sub 6}Sn{sub 5} intermetallic powder production route was proposed. • Single phase Cu{sub 6}Sn{sub 5} powders could be by water atomization and heating. • Water-atomized Cu–Sn powders contained mixed Cu–Sn phases. • Solidification and heat treatment of water-atomized Cu–Sn powders are explained.

  17. Preparation of superconductor precursor powders

    Science.gov (United States)

    Bhattacharya, Raghunath; Blaugher, Richard D.

    1995-01-01

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

  18. (TECTONA GRANDIS LEAF POWDER

    Directory of Open Access Journals (Sweden)

    Yash Mishra

    2015-01-01

    Full Text Available In this study, the adsorption potential of Teak (Tectona grandis leaf powder (TLP toremove Methylene blue (MB and Malachite Green (MG dye molecules from aqueoussolution was investigated. Batch experiments were conducted to evaluate the influenceof operational parameters such as, pH (2−9, adsorbent dosage (1−7 g/L, contact time(15−150 minutes and initial dye concentration (20−120 mg/L at stirring speed of 150rpm for the adsorption of MB and MG on TLP. Maximum removal efficiency of 98.4%and 95.1% was achieved for MB and MG dye, respectively. The experimentalequilibrium data were analysed using Langmuir, Freundlich and Temkin isothermmodels and it was found that, it fitted well to the Freundlich isotherm model. Thesurface structure and morphology of the adsorbent was characterized using scanningelectron microscopy (SEM and the presence of functional groups and its interactionwith the dye molecules were analysed using Fourier transform infrared spectroscopy(FTIR. Based on the investigation, it has been demonstrated that the teak leaf powderhas good potential for effective adsorption of methylene blue and malachite green dye.

  19. Single and double-layer composite microwave absorbers with hexaferrite BaZn{sub 0.6}Zr{sub 0.3}X{sub 0.3}Fe{sub 10.8}O{sub 19} (X = Ti, Ce, Sn) powders

    Energy Technology Data Exchange (ETDEWEB)

    Afghahi, Seyyed Salman Seyyed [Department of Materials Science and Engineering, Imam Hossein University, Tehran (Iran, Islamic Republic of); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Atassi, Yomen [Department of Applied Physics, Higher Institute for Applied Sciences and Technology, Damascus (Syrian Arab Republic); Stergiou, Charalampos A. [Lab. of Inorganic Materials, Centre for Research and Technology Hellas, 57001, Thermi (Greece)

    2017-01-15

    In the present study, substituted barium hexaferrites with the composition BaZn{sub 0.6}Zr{sub 0.3} × {sub 0.3}Fe{sub 10.8}O{sub 19} (where X = Ti, Ce, Sn) are prepared with the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and network analysis techniques are used to analyze the crystal phases, morphology, static magnetic and microwave absorption properties, respectively. Based on the recorded results, barium hexaferrite is the major phase obtained after milling of the powders for 20 h, followed by calcination at 1000 °C for 5 h. The morphology of the particles of the substituted ferrite samples is plate-like with hexagonal shape. The microwave absorption in the X-band of epoxy composites loaded with the ferrite fillers, either separately, in pairs or all together, has been extensively investigated. Multicomponent composites filled with the new hexaferrites under study are promising candidates for electromagnetic absorbers in the 8–12 GHz range. It is found that single-layer absorbers of 5 mm thickness with 45 wt% of a binary (Sn and Ti-doped hexaferrite) or ternary filler mixture exhibit the maximum bandwidth of 2.7 GHz at the level of −10 dB or maximum losses of 26.4 dB at 10.8 GHz, respectively. - Highlights: • Preparation of substituted hexaferrites via mechanical activation. • We designed a broad band microwave absorber with mixing powders. • We designed single layer absorber with RL{sub min} = −26.4 dB and 1.6 GHz bandwidth. • We designed double layer absorbers, as monoband absorbers at a matching frequency.

  20. One step HIP canning of powder metallurgy composites

    Science.gov (United States)

    Juhas, John J. (Inventor)

    1990-01-01

    A single step is relied on in the canning process for hot isostatic pressing (HIP) powder metallurgy composites. The binders are totally removed while the HIP can of compatible refractory metal is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.

  1. Structure and shear in a cohesive powder

    NARCIS (Netherlands)

    Janssen, R.J.M.

    2001-01-01

    Handling of powders and granular materials is of great importance to industry. However, the knowledge of many powder related processes in industry is poor. In this work, the flow behaviour of powder has been investigated with an advanced tester: the Flexible Wall Biaxial Tester. Flow of powder

  2. On the Methods to Measure Powder Flow.

    Science.gov (United States)

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

    2015-01-01

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

  3. Development of a Reproducible Powder Characterization Method using a Powder Rheometer

    DEFF Research Database (Denmark)

    Søgaard, Søren Vinter; Allesø, Morten; Garnæs, Jørgen

    2012-01-01

    In this study, a powder rheometer was used to measure flow characteristics of two pharmaceutical model powders. Precise measurements were obtained for one of the model powders whereas the results were less precise for the second powder. In conclusion, further work is needed to increase...... the mechanistic understanding of powder rheological measurements....

  4. Low temperature synthesis of magnesium oxide and spinel powders by a sol-gel process

    Directory of Open Access Journals (Sweden)

    Li-Zhai Pei

    2010-09-01

    Full Text Available Magnesium oxide and magnesium aluminate (MgAl2O4 spinel (MAS powders have been synthesized by a simple aqueous sol-gel process using citrate polymeric precursors derived from magnesium chloride, aluminium nitrate and citrate. The thermal decomposition of the precursors and subsequent formation of cubic MgO and MAS were investigated by X-ray diffraction (XRD, scanning electron microscopy (SEM, thermogravimetry-differential scanning calorimetry (TG-DSC and Fourier transform infrared spectra (FTIR. The single phase cubic MgO powder and MAS powder form after heat treatment at 800 and 1200 °C, respectively. The particle size of the MgO and MAS powders is about 100 nm and several micrometers, respectively. Ball milling eliminates the size of MgO and MgAl2O4 spinel powders by decreasing the conglomeration of the powders.

  5. Monitoring protein precipitates by in-house X-ray powder diffraction

    DEFF Research Database (Denmark)

    Ståhl, Kenny; Frankær, Christian Grundahl; Petersen, Jakob

    2013-01-01

    Powder diffraction from protein powders using in-house diffractometers is an effective tool for identification and monitoring of protein crystal forms and artifacts. As an alternative to conventional powder diffractometers a single crystal diffractometer equipped with an X-ray micro-source can...... of protein data sets in the database some problems can be foreseen due to the large number of overlapping peaks in the low-angle region, and small differences in unit cell parameters between pdb-data and powder data. It is suggested that protein entries are supplied with more searchable keywords as protein...... be used to collect powder patterns from 1 l samples. Using a small-angle X-ray scattering (SAXS) camera it is possible to collect data within minutes. A streamlined program has been developed for the calculation of powder patterns from pdb-coordinates, and includes correction for bulk-solvent. A number...

  6. Application of Composite Powders Recycled from Graphite Tailings in Styrene-Butadiene Rubber

    Science.gov (United States)

    Hai, Yun; Liao, Libing; Lv, Guocheng; Qin, Faxiang; Mei, Lefu; Wei, Yaozu

    2015-11-01

    With styrene-butadiene rubber (SBR) as matrix and composite powders recycled from graphite tailings as fillers, the influence of the particle size and content of the composite powders on the tensile strength and electrical conductivity of the composite powder-filled SBR were studied. The results showed that composite powder recycled from graphite tailings could reinforce SBR, whose tensile strength was significantly increased with reducing the particle size of the composite powder, but it had little effect on the conductivity of the system. With composite powders as fillers in conjunction with conductive carbon black, the tensile strength and electrical conductivity of the system were greatly improved. The maximum tensile strength of the SBR filled with composite powder and conductive carbon black increased by 47% compared to that of the single composite powder-filled SBR. When the filling content of conductive carbon black was 10 phr and that of composite powder was above 30 phr, the volume resistivity of SBR showed a sharp decline, reaching a minimum about 106 Ω cm at 40 phr. All the results indicated that composite powder recycled from graphite tailings can be applied effectively as filler in SBR. It has great economic and environmental benefits.

  7. Sinterable Ceramic Powders from Laser-Heated Gases.

    Science.gov (United States)

    1988-02-01

    Reactions 25 3. Crystal Structure of Silicon Powders Produced from Laser-Heated Silane 37 IV . Post Synthesis Processing 1. Wetting and Dispersion of Silicon...Society, Session IV , High Temperature Materials Synthesis, Honolulu, Hawaii, Oct. 18-23, 1987 p87-05 IAS S! SIZM CAauiC POWDES: Sy XDS, c ZMUISTICS...ether. carboxylic acid. and aldehyde clases : water is also included.Acrigto William and Goodman.’ a single crystalline sili- The single-crstalline

  8. Electrodeposition of Fe powder from acid electrolytes

    Directory of Open Access Journals (Sweden)

    VESNA M. MAKSIMOVIC

    2008-08-01

    Full Text Available Polarization characteristics of the electrodeposition processes of Fe powders from sulfate and chloride electrolytes and the morphology of the obtained powders were investigated. The morphology depended on the anion presence in the electrolyte but not on the current density in the investigated range. A characteristic feature of the dendritic powder with cauliflower endings obtained from sulfate electrolyte is the presence of cone-like cavities and the crystallite morphology of the powders surface. On the other hand, Fe powders electrodeposited from chloride electrolyte appear in the form of agglomerates. A soap solution treatment applied as a method of washing and drying provides good protection from oxidation of the powders.

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

    Science.gov (United States)

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

    2004-05-01

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

  10. Mask materials for powder blasting

    NARCIS (Netherlands)

    Wensink, H.; Jansen, Henricus V.; Berenschot, Johan W.; Elwenspoek, Michael Curt

    Powder blasting, or abrasive jet machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials such as glass, silicon and ceramics. The particle jet (which

  11. High resolution powder blast micromachining

    NARCIS (Netherlands)

    Wensink, H.; Berenschot, Johan W.; Jansen, Henricus V.; Elwenspoek, Michael Curt

    2000-01-01

    Powder blasting, or Abrasive Jet Machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials like glass, silicon and ceramics. By introducing electroplated

  12. Phonons from neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrov, D.A.; Louca, D.; Roeder, H. (Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States))

    1999-09-01

    The spherically averaged structure function S([vert bar][bold q][vert bar]) obtained from pulsed neutron powder diffraction contains both elastic and inelastic scattering via an integral over energy. The Fourier transformation of S([vert bar][bold q][vert bar]) to real space, as is done in the pair density function (PDF) analysis, regularizes the data, i.e., it accentuates the diffuse scattering. We present a technique which enables the extraction of off-center ([vert bar][bold q][vert bar][ne]0) phonon information from powder diffraction experiments by comparing the experimental PDF with theoretical calculations based on standard interatomic potentials and the crystal symmetry. This procedure [dynamics from powder diffraction] has been [ital successfully] implemented as demonstrated here for two systems, a simple metal fcc Ni and an ionic crystal CaF[sub 2]. Although computationally intensive, this data analysis allows for a phonon based modeling of the PDF, and additionally provides off-center phonon information from neutron powder diffraction. [copyright] [ital 1999] [ital The American Physical Society

  13. Uranium Carbide Powder Ignition Studies

    Energy Technology Data Exchange (ETDEWEB)

    Berthinier, C.; Coullomb, S.; Rado, C.; Le Guyadec, F. [CEA, DEN, DTEC, SDTC, LEME, F-30207 Bagnols-sur-Ceze (France); Chatillon, C.; Blanquet, E.; Boichot, R. [SIMAP, Sciences et Ingenierie des Materiaux et Procedes, INPG-CNRS-UJF ENSEEG, BP 75, 38402 St Martin-d' Heres (France)

    2009-06-15

    Mixed (U, Pu) carbide, constituted by means of 80% of uranium monocarbide (UC), is considered as a possible fuel material for future gas fast reactors or sodium fast reactor. However, UC undergoes a strong exothermic reaction with air and fine powders of UC are pyrophoric. Thus, it is necessary to understand this high reactivity in order to determine safe handling conditions for the production and reprocessing of carbide fuels. UC powder was obtained by arc melting and milling. The reactivity of uranium carbide was studied in oxidizing atmosphere and different experimental devices were used to determine ignition temperatures. The phases formed at the various observed stages of the oxidation process were determined by post-mortem X ray diffraction analysis. Studies were first performed using small quantities of UC powder (around 50 mg) in Differential Thermal Analysis / Thermogravimetric Analysis (DTA/TGA) and Differential Scanning Calorimetry (DSC). Experiments were realized using different parameters, such as heating rate and gas flow rate and composition, to determine their influence on pyro-phoricity. Results obtained with small quantities (tens of milligrams) revealed that UC powder is highly reactive in air in the range 200- 250 deg. C. Studies were also performed in the 'Pyro' test facility multi-function furnace allowing CCD camera recording, during heating and ignition, through view-ports. Lower ignition temperatures, around 100 deg. C, were obtained using around 1 g UC powder samples. Results are discussed and analysed with theory of burning curve ignition and numerical simulations. Simulations aim to understand the influence of the different parameters on pyro-phoricity. Small scale simulations (on a spherical grain) confirm the influence of UC grains size, heat rate and gas composition on powder ignition temperature with small quantities. The issue is now to understand the influence of grain pile form factor and volume on the pyro-phoricity of

  14. Er:SrF{sub 2} luminescent powders prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rakov, Nikifor, E-mail: nkifor.gomez@univasf.edu.br [PG - Ciencia dos Materiais, Universidade Federal do Vale do Sao Francisco, 48902-300 Juazeiro, BA (Brazil); Guimaraes, R.B.; Franceschini, D.F.; Maciel, Glauco S. [Instituto de Fisica, Universidade Federal Fluminense, 24210-346 Niteroi, RJ (Brazil)

    2012-08-15

    Combustion synthesis, a widely spread technique employed to produce low-cost high-yield oxide powders, was used to prepare fluoride powders for the first time. Surface morphology and structure of erbium (Er{sup 3+}) doped strontium fluoride (SrF{sub 2}) powders were investigated by scanning electronic microscopy, energy dispersive X-ray and X-ray powder diffraction. Samples were prepared with and without aluminum (Al) and we observed that the presence of Al helps the powder to crystallize in a pure SrF{sub 2} single cubic phase. Luminescence spectral analysis was also performed and we observed that among the samples investigated the Er{sup 3+}:SrF{sub 2} powder prepared with Al using glycine is the most efficient luminescence up-converter. The luminescence results concords with Raman data of the samples. -- Highlights: Black-Right-Pointing-Pointer Strontium fluoride powders are prepared by combustion synthesis for the first time. Black-Right-Pointing-Pointer Structural characterization and luminescence analysis of powders prepared using two different fuels: glycine and urea. Black-Right-Pointing-Pointer Analysis of the influence of aluminum on the powders structure and luminescence properties. Black-Right-Pointing-Pointer First time, to the best of our knowledge, that Raman spectroscopy is performed in SrF{sub 2} nanostructured material.

  15. Polymer quenched prealloyed metal powder

    Science.gov (United States)

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

    2001-01-01

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

  16. 21 CFR 73.2645 - Aluminum powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.2645 Section 73.2645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2645 Aluminum powder. (a) Identity and specifications. The color additive aluminum powder shall conform in identity and specifications to the requirements of...

  17. 21 CFR 73.1645 - Aluminum powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Aluminum powder. 73.1645 Section 73.1645 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1645 Aluminum powder. (a) Identity. (1) The color additive aluminum powder shall be composed of finely divided particles of aluminum prepared from virgin aluminum. It...

  18. Metallurgical Characterization of Aluminum Powder Consolidation.

    Science.gov (United States)

    1987-05-01

    theoretical density could be obtained by cold compacting Al powder. The apparent lack of inter- particle bonding in Figure 13 is due to heavy etching of the...34 ring seal Crimp hold Figure 39. Powder pack as assembled. 47 • .U % . * .,Z . % Ignition PVC tube (21.6 cm O.D., 20 cm l.D.) ON 30cm Powder pack ANFO

  19. 21 CFR 520.1696a - Buffered penicillin powder, penicillin powder with buffered aqueous diluent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Buffered penicillin powder, penicillin powder with... FORM NEW ANIMAL DRUGS § 520.1696a Buffered penicillin powder, penicillin powder with buffered aqueous diluent. (a) Specifications. When reconstituted, each milliliter contains penicillin G procaine equivalent...

  20. [Impact of directly compressed auxiliary materials on powder property of fermented cordyceps powder].

    Science.gov (United States)

    Chen, Li-Hua; Yue, Guo-Chao; Guan, Yong-Mei; Yang, Ming; Zhu, Wei-Feng

    2014-01-01

    To investigate such physical indexes as hygroscopicity, angle of repose, bulk density, fillibility of compression of mixed powder of directly compressed auxiliary materials and fermented cordyceps powder by using micromeritic study methods. The results showed that spray-dried lactose Flowlac100 and microcrystalline cellulose Avicel PH102 had better effect in liquidity and compressibility on fermented cordyceps powder than pregelatinized starch. The study on the impact of directly compressed auxiliary materials on the powder property of fermented cordyceps powder had guiding significant to the research of fermented cordyceps powder tablets, and could provide basis for the development of fermented cordyceps powder tablets.

  1. Preparation of lanthanum ferrite powder at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Andoulsi, R.; Horchani-Naifer, K.; Ferid, M., E-mail: karima_horchani@yahoo.com [Physical Chemistry Laboratory of Mineral Materials and their Applications, Hammam-Lif (Tunisia)

    2012-01-15

    Single lanthanum ferrite phase was successfully prepared at low processing temperature using the polymerizable complex method. To implement this work, several techniques such as differential scanning calorimetry, X-ray diffraction, Fourier Transform Infrared Spectroscopy, scanning electron microscopy and BET surface area measurements were used. Throw the obtained results, it was shown that steps of preparing the powder precursor and temperature of its calcination are critical parameters for avoiding phase segregation and obtaining pure lanthanum ferrite compound. Thus, a single perovskite phase was obtained at 600 deg C. At this temperature, the powder was found to be fine and homogeneous with an average crystallite size of 13 nm and a specific surface area of 12.5 m{sup 2}.g{sup -1}. (author)

  2. Changes in selected oxysterols in powdered foodstuffs

    Directory of Open Access Journals (Sweden)

    Sylwia Chudy

    2016-01-01

    Full Text Available The present research consisted of producing 3 types of powdered concentrates: the dairy, the egg and the dairy-egg (produced from a blend of raw liquid milk and liquid eggs. The dairy-egg powder was produced in order to facilitate formulation of dry food mixes. Powders were vacuumpackaged and packaged in air atmosphere and stored for 24 months. Changes in contents of selected oxysterols (determined by gas chromatography were recorded. Regardless of the packaging type, the predominant oxysterol in the dairy-egg powder was α-epoxy-C (7.679 and 5.600 μg/g powder, respectively.

  3. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  4. Preparation of antimony trioxide powder

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyung Kyu; Jang, Hee Dong; Km, Joon Soo; Lim, Young Woong; Kim, Sung Don; Yoon, Ho Sung; Lee, Hoo In; Kim, Chul Joo [Korea Institute of Geology Mining and Materials, Taejon (Korea)

    1998-12-01

    Antimony trioxide is used as flame retardant material in plastic, rubber, and textile industries. It was carried out to establish processing technology of antimony trioxide, and provide for smelting of metallic antimony by domestic industries. Also, domestic market of antimony trioxide was surveyed. Commercial antimony trioxide has been manufactured through two steps : the first is to extract antimony metal from Stibnite ore, and the second is to evaporate and oxidize metallic antimony. In this study, it was focused on the second step because primary antimony has not been produced domestically. An equipment for melting and vaporizing of metallic antimony was experimentally prepared. Antimony metal was melted in magnesia crucible, and reacted with air to oxidize into antimony trioxide powder in the equipment by use of suction blower. The powder was collected through bag filter. The crystal form of the antimony trioxide sample was senarmontite. The shape of the powder was widely spherical. It is considered that antimony trioxide could be prepared effectively through the experiment. (author). 9 figs.

  5. Dynamic compaction of ceramic powders

    Energy Technology Data Exchange (ETDEWEB)

    Cline, C.F.

    1982-06-10

    Dynamic consolidation is a technique for densifying powder ensembles to near theoretical with or without external application of heat. The technique itself is simple: the confined powder, initially at a green density of approx. 50% encounters a high pressure shock wave which exceeds the yield strength and densifies as the wave proceeds through the compact. The time scales and pressure range from 1-10's of microseconds and 10-100's of kilobars (10 Kb = 1 GPa). The short time scale of the pressure pulse during the compaction stage inhibits kinetic processes which have longer time constants. The pressure pulse can be delivered to the green compact by a number of techniques, i.e. high explosive, projectile. The methods differ in the degree that one can control the amplitude, duration, and nature of the pressure pulse. The lecture compares powders compacted by explosive and light gas guns and when possible characterize their resulting structures and properties, using AlN as example. 14 figures.

  6. AFRL’s HP3 60mm Powder Gun

    Science.gov (United States)

    2012-08-08

    amount tissue paper for wadding. The primer is activated via a solenoid -driven firing pin. Once ignited, the black powder travels down the igniter...used at the HP3 facility. Both VISARs share a single Coherent Verdi (532 nm) 6 Watt Laser as the light source. The light is transmitted from the laser ...for the crush pin signals to propagate to the recorders is not matched to the time for the optical signals to reach the recorders, it is not expected

  7. Tailored Core Shell Cathode Powders for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Swartz, Scott [NexTech Materials, Ltd.,Lewis Center, OH (United States)

    2015-03-23

    In this Phase I SBIR project, a “core-shell” composite cathode approach was evaluated for improving SOFC performance and reducing degradation of lanthanum strontium cobalt ferrite (LSCF) cathode materials, following previous successful demonstrations of infiltration approaches for achieving the same goals. The intent was to establish core-shell cathode powders that enabled high performance to be obtained with “drop-in” process capability for SOFC manufacturing (i.e., rather than adding an infiltration step to the SOFC manufacturing process). Milling, precipitation and hetero-coagulation methods were evaluated for making core-shell composite cathode powders comprised of coarse LSCF “core” particles and nanoscale “shell” particles of lanthanum strontium manganite (LSM) or praseodymium strontium manganite (PSM). Precipitation and hetero-coagulation methods were successful for obtaining the targeted core-shell morphology, although perfect coverage of the LSCF core particles by the LSM and PSM particles was not obtained. Electrochemical characterization of core-shell cathode powders and conventional (baseline) cathode powders was performed via electrochemical impedance spectroscopy (EIS) half-cell measurements and single-cell SOFC testing. Reliable EIS testing methods were established, which enabled comparative area-specific resistance measurements to be obtained. A single-cell SOFC testing approach also was established that enabled cathode resistance to be separated from overall cell resistance, and for cathode degradation to be separated from overall cell degradation. The results of these EIS and SOFC tests conclusively determined that the core-shell cathode powders resulted in significant lowering of performance, compared to the baseline cathodes. Based on the results of this project, it was concluded that the core-shell cathode approach did not warrant further investigation.

  8. FUNDAMENTAL STUDIES OF THE DISPERSIBILITY OF POWDERED MATERIALS

    Science.gov (United States)

    respectively. Late in the program, a fourth powder ( egg albumin ) was added to the list of powders to be investigated. The preparation of powders including...effects of ad sorbed foreign vapors on powder properties, (7) effects of removal of adsorbed gases and vapors, (8) energy required to disperse a powder sample, (9) properties of compacted powders, and (10) egg albumin studies.

  9. Characterization of yttria-doped zirconia powders produced by plasma-chemical method

    DEFF Research Database (Denmark)

    Kuzjukevics, A.; Linderoth, Søren; Grabis, J.

    1996-01-01

    Ultrafine non-doped and yttria-doped zirconia (ZY) powders have been produced by a single-step plasma synthesis method. The amount of yttria doping was varied between 0 and about 10 mol%. The phase composition, structural parameters and morphology of the as-prepared powders have been examined by X...... transmission electron microscopy. The ZY ultrafine powders were mixtures of a cubic and a non-transformable tetragonal zirconia phases. The amount of the tetragonal phase decreased with the overall yttria content but with a composition that remained almost the same. Neutron diffraction revealed diffuse...

  10. Roller compaction of moist pharmaceutical powders.

    Science.gov (United States)

    Wu, C-Y; Hung, W-L; Miguélez-Morán, A M; Gururajan, B; Seville, J P K

    2010-05-31

    The compression behaviour of powders during roller compaction is dominated by a number of factors, such as process conditions (roll speed, roll gap, feeding mechanisms and feeding speed) and powder properties (particle size, shape, moisture content). The moisture content affects the powder properties, such as the flowability and cohesion, but it is not clear how the moisture content will influence the powder compression behaviour during roller compaction. In this study, the effect of moisture contents on roller compaction behaviour of microcrystalline cellulose (MCC, Avicel PH102) was investigated experimentally. MCC samples of different moisture contents were prepared by mixing as-received MCC powder with different amount of water that was sprayed onto the powder bed being agitated in a rotary mixer. The flowability of these samples were evaluated in terms of the poured angle of repose and flow functions. The moist powders were then compacted using the instrumented roller compactor developed at the University of Birmingham. The flow and compression behaviour during roller compaction and the properties of produced ribbons were examined. It has been found that, as the moisture content increases, the flowability of moist MCC powders decreases and the powder becomes more cohesive. As a consequence of non-uniform flow of powder into the compaction zone induced by the friction between powder and side cheek plates, all produced ribbons have a higher density in the middle and lower densities at the edges. For the ribbons made of powders with high moisture contents, different hydration states across the ribbon width were also identified from SEM images. Moreover, it was interesting to find that these ribbons were split into two halves. This is attributed to the reduction in the mechanical strength of moist powder compacts with high moisture contents produced at high compression pressures. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  11. Adsorption of lignosulfonate compounds using powdered eggshell

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Zulfikar

    2012-07-01

    Full Text Available Batch adsorption of lignosulfonates using untreated powdered eggshell under the influences of mixing time, pH,particle size and dose of powdered eggshell was investigated. Adsorption isotherms of lignosulfonates onto powder eggshellwere also studied. Eggshells were collected from the Balubur traditional market in Bandung, Indonesia, washed with distilledwater, air dried, and then ground into powder of different particle sizes. Kinetic studies found that equilibrium time was ashigh as 90 minutes. From experiments carried out at different pH, it was observed that pH plays an important role in theadsorption of lignosulfonate compounds. It was also observed that particles size has no significant effect on the adsorptionof lignosulfonate compounds. The optimum dosage of powdered eggshell was 30 g/100 mL of 500 mg/L lignosulfonatesolution. Adsorption isotherms studied through the use of graphical methods revealed that the adsorption of lignosulfonatesonto powdered eggshell follows the Langmuir model.

  12. Indigenous tooth powders = covert lead poisoning?

    Science.gov (United States)

    Hegde, Sapna; Shubha, A B; Rao, B Dinesh

    2013-01-01

    The present study aimed to measure the concentration of lead in various indigenous preparations of tooth powders available and used locally in and around Udaipur, Rajasthan, India. Seven different brands of tooth powders manufactured and/or marketed locally were obtained from stores all over Udaipur city. Some home-made powders commonly used for cleaning teeth were also collected. The tooth powders were analyzed for lead content by atomic absorption spectrophotometry. All tooth powders tested were found to contain high levels of lead ranging from 21 ppm to 82 ppm, above the maximum permissible level of 20 ppm prescribed by the Bureau of Indian Standards. Indigenous tooth powders contain high levels of lead and thus may be a source of lead poisoning that is often overlooked.

  13. Sun drying of residual annatto seed powder

    OpenAIRE

    Dyego da Costa Santos; Alexandre José de Melo Queiroz; Rossana Maria Feitosa de Figueirêdo; Emanuel Neto Alves de Oliveira

    2015-01-01

    Residual annatto seeds are waste from bixin extraction in the food, pharmaceutical and cosmetic industries. Most of this by-product is currently discarded; however, the use of these seeds in human foods through the elaboration of powder added to other commercial powders is seen as a viable option. This study aimed at drying of residual annatto powder, with and without the oil layer derived from the industrial extraction of bixin, fitting different mathematical models to experimental data and ...

  14. In-house characterization of protein powder

    DEFF Research Database (Denmark)

    Hartmann, Christian Grundahl; Nielsen, Ole Faurskov; Ståhl, Kenny

    2010-01-01

    X-ray powder diffraction patterns of lysozyme and insulin were recorded on a standard in-house powder diffractometer. The experimental powder diffraction patterns were compared with patterns calculated from Protein Data Bank coordinate data. Good agreement was obtained by including straightforward...... to include calculated H-atom positions did not improve the overall fit and was abandoned. The method devised was shown to be a quick and convenient tool for distinguishing precipitates and polymorphs of proteins....

  15. Recovery of yttrium from cathode ray tubes and lamps’ fluorescent powders: experimental results and economic simulation

    Energy Technology Data Exchange (ETDEWEB)

    Innocenzi, V., E-mail: valentina.innocenzi1@univaq.it; De Michelis, I.; Ferella, F.; Vegliò, F.

    2013-11-15

    Highlights: • Fluorescent powder of lamps. • Fluorescent powder of cathode ray rubes. • Recovery of yttrium from fluorescent powders. • Economic simulation for the processes to recover yttrium from WEEE. - Abstract: In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides. Experimental results have shown that process conditions necessary to purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%. Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes.

  16. CVD carbon powders modified by ball milling

    Directory of Open Access Journals (Sweden)

    Kazmierczak Tomasz

    2015-09-01

    Full Text Available Carbon powders produced using a plasma assisted chemical vapor deposition (CVD methods are an interesting subject of research. One of the most interesting methods of synthesizing these powders is using radio frequency plasma. This method, originally used in deposition of carbon films containing different sp2/sp3 ratios, also makes possible to produce carbon structures in the form of powder. Results of research related to the mechanical modification of these powders have been presented. The powders were modified using a planetary ball mill with varying parameters, such as milling speed, time, ball/powder mass ratio and additional liquids. Changes in morphology and particle sizes were measured using scanning electron microscopy and dynamic light scattering. Phase composition was analyzed using Raman spectroscopy. The influence of individual parameters on the modification outcome was estimated using statistical method. The research proved that the size of obtained powders is mostly influenced by the milling speed and the amount of balls. Powders tend to form conglomerates sized up to hundreds of micrometers. Additionally, it is possible to obtain nanopowders with the size around 100 nm. Furthermore, application of additional liquid, i.e. water in the process reduces the graphitization of the powder, which takes place during dry milling.

  17. Enzyme-linked immunosorbent assay for the detection of bovine rennet whey powder in milk powder and buttermilk powder

    NARCIS (Netherlands)

    Bremer, M.G.E.G.; Kemmers-Voncken, A.; Boers, E.A.M.; Frankhuizen, R.; Haasnoot, W.

    2008-01-01

    An inhibition enzyme-linked immunosorbent assay (ELISA) for the detection of bovine rennet whey (BRW) solids in skim milk powders (SMP) and buttermilk powders is presented. The BRW content was determined in a neutralised trichloroacetic acid sample extract by binding of the dissolved

  18. Recovery of yttrium from cathode ray tubes and lamps' fluorescent powders: experimental results and economic simulation.

    Science.gov (United States)

    Innocenzi, V; De Michelis, I; Ferella, F; Vegliò, F

    2013-11-01

    In this paper, yttrium recovery from fluorescent powder of lamps and cathode ray tubes (CRTs) is described. The process for treating these materials includes the following: (a) acid leaching, (b) purification of the leach liquors using sodium hydroxide and sodium sulfide, (c) precipitation of yttrium using oxalic acid, and (d) calcinations of oxalates for production of yttrium oxides. Experimental results have shown that process conditions necessary to purify the solutions and recover yttrium strongly depend on composition of the leach liquor, in other words, whether the powder comes from treatment of CRTs or lamp. In the optimal experimental conditions, the recoveries of yttrium oxide are about 95%, 55%, and 65% for CRT, lamps, and CRT/lamp mixture (called MIX) powders, respectively. The lower yields obtained during treatments of MIX and lamp powders are probably due to the co-precipitation of yttrium together with other metals contained in the lamps powder only. Yttrium loss can be reduced to minimum changing the experimental conditions with respect to the case of the CRT process. In any case, the purity of final products from CRT, lamps, and MIX is greater than 95%. Moreover, the possibility to treat simultaneously both CRT and lamp powders is very important and interesting from an industrial point of view since it could be possible to run a single plant treating fluorescent powder coming from two different electronic wastes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Experimental Equipment for Powder Processing

    Science.gov (United States)

    2009-08-20

    Al2O3/ZrO2 FGM samples. 3.3.4 CTEs measurement [29, 30] By in situ reaction of WO3 to ZrO2, we fabricated various ZrW2O8 /ZrO2 composites, as listed in...Table 6. Table 6 The WO3/ZrO2 mass ratios of various green samples and the corresponding resultant ZrW2O8 /ZrO2 volume ratios in the sintered...samples. # WO3/ZrO2 mass ratio in reactant powder ZrW2O8 /ZrO2 volume ratios in the sintered sample Final relative density 1 0.159:1 20:80 77% 2

  20. Hydrothermal synthesis of fine oxide powders

    Indian Academy of Sciences (India)

    Unknown

    Inorganic powders are among the most important factors in many fields of materials such as ceramics, catalysts, medicines, food, etc. There are many papers and books related to powders preparation by many authors (Veale. 1972; Kato and Yamaguchi 1983; Vincenzini 1983;. Brinker et al 1984; Johnson Jr. 1987; Messing ...

  1. Evaluating the Johanson theory for titanium powder

    CSIR Research Space (South Africa)

    Chikosha, S

    2015-05-01

    Full Text Available . In this study, the Johanson theory was used to determine the rolling parameters of titanium powder. Preliminary results of the nip angle, nip pressures and maximum horizontal pressures of the mill for the powder rolled on a 55mm diameter roll with roll gap sizes...

  2. Autoclave heat treatment for prealloyed powder products

    Science.gov (United States)

    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.

  3. Jetting formation of the explosively loaded powders

    Science.gov (United States)

    Xue, Kun; Yu, Qiqi

    2017-10-01

    The formation of jet-like structures is widely reported in the explosive dispersal of powders surrounding high explosive charges. The jetting of powder beds initiates upon the shock wave reaches the outer edge of the charge. Opposed to the interface instability theory, a hollow sphere based bulk fragmentation model is established to account for the jetting of powders. A two-phase process, namely the nucleation and free expansion of hollow spheres, corresponds to the unloading process of the powder compact caused by the rarefaction waves which governs the fragmentation of the powders. The separation between adjacent hollow spheres dictates the size of the particle clusters, which would evolve into particle jets in later times. The predicted breakup time and the size of particle jets agree well with the experimental results. The increased moisture content in powders results in an increased number of particle jets. This moisture effect can be understood in light of the varied energy distribution due to the incompressibility of the interstitial liquids trapped inside the inter-grain pores. The portion of shock energy which is not consumed in the shock compaction of the wet powders would be dissipated through the viscous shear flows during the unloading of the wet powder compact. The excessive viscous energy requires to activate more localized shear flows, accordingly leading to an increased number of particle jets.

  4. Characterization of mock high-explosive powder

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, C.R.; Dorsey, G.F.

    1979-03-01

    Analytical characterization and explosibility tests were made on a simulative high-explosive powder consisting of cyanuric acid, melamine, nitrocellulose, and tris-(..beta..-chloroethyl)-phosphate. Tests indicated that the powder presents no unusual safety or health hazards in isostatic-pressing and dry-machining operations.

  5. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a temperature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders prepared ...

  6. Slip casting and nitridation of silicon powder

    Science.gov (United States)

    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.

  7. Computational modelling for dry-powder inhalers

    NARCIS (Netherlands)

    Kröger, Ralf; Woolhouse, Robert; Becker, Michael; Wachtel, Herbert; de Boer, Anne; Horner, Marc

    2012-01-01

    Computational fluid dynamics (CFD) is a simulation tool used for modelling powder flow through inhalers to allow optimisation both of device design and drug powder. Here, Ralf Kröger, Consulting Senior CFD Engineer, ANSYS Germany GmbH; Marc Horner, Lead Technical Services Engineer, Healthcare,

  8. Wet powder seal for gas containment

    Science.gov (United States)

    Stang, Louis G.

    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.

  9. Electronic Nose Study of Powdered Garlic

    Directory of Open Access Journals (Sweden)

    Rosa E. Baby

    2009-08-01

    Full Text Available An electronic nose was used to study the odour profile of garlic, separating the powered samples of eight cultivars and proving to be useful to discriminate garlic specimen dried by lyophilization and oven-dried and humidified specimen (before dried by both techniques for each cultivar. Pattern recognition and multivariate analysis of the electronic nose data has enabled to easily separate the garlic cultivars, to clearly discriminate the lyophilized or oven-dried specimen and the non humidified samples from the humidified powders maintaining, in every case, the cultivars identification. The humidification of lyophilized powders has shown a sharp separation of cultivars, otherwise, in the humidified oven-dried powders, their identification resulted less precise. This fact enabled to infer that lyophilized powders (either dry or humidified better retained their odour profile than oven-dried powders, maintaining the properties of each cultivar.

  10. Sun drying of residual annatto seed powder

    Directory of Open Access Journals (Sweden)

    Dyego da Costa Santos

    2015-01-01

    Full Text Available Residual annatto seeds are waste from bixin extraction in the food, pharmaceutical and cosmetic industries. Most of this by-product is currently discarded; however, the use of these seeds in human foods through the elaboration of powder added to other commercial powders is seen as a viable option. This study aimed at drying of residual annatto powder, with and without the oil layer derived from the industrial extraction of bixin, fitting different mathematical models to experimental data and calculating the effective moisture diffusivity of the samples. Powder containing oil exhibited the shortest drying time, highest drying rate (≈ 5.0 kg kg-1 min-1 and highest effective diffusivity (6.49 × 10-12 m2 s-1. All mathematical models assessed were a suitable representation of the drying kinetics of powders with and without oil, with R2 above 0.99 and root mean square error values lower than 1.0.

  11. Monte Carlo simulation of light reflection from cosmetic powders on the skin

    Science.gov (United States)

    Okamoto, Takashi; Motoda, Masafumi; Igarashi, Takanori; Nakao, Keisuke

    2011-07-01

    The reflection and scattering properties of light incident on skin covered with powder particles have been investigated. A three-layer skin structure with a spot is modeled, and the propagation of light in the skin and the scattering of light by particles on the skin surface are simulated by means of a Monte Carlo method. Under the condition in which only single scattering of light occurs in the powder layer, the reflection spectra of light from the skin change dramatically with the size of powder particles. The color difference between normal skin and spots is found to diminish more when powder particles smaller than the wavelength of light are used. It is shown that particle polydispersity suppresses substantially the extreme spectral change caused by monodisperse particles with a size comparable to the light wavelength.

  12. Powder strength distributions for understanding de-agglomeration of lactose powders.

    Science.gov (United States)

    Das, Shyamal C; Behara, Srinivas Ravindra Babu; Bulitta, Jurgen B; Morton, David A V; Larson, Ian; Stewart, Peter J

    2012-10-01

    The purpose was to calculate distributions of powder strength of a cohesive bed to explain the de-agglomeration of lactose. De-agglomeration profiles of Lactohale 300(®) (L300) and micronized lactose (ML) were constructed by particle sizing aerosolised plumes dispersed at air flow rates of 30-180 l/min. The work of cohesion distribution was determined by inverse gas chromatography. The primary particle size and tapped density distributions were determined. Powder strength distributions were calculated by Monte Carlo simulations from distributions of particle size, work of cohesion and tapped density measurements. The powder strength distribution of L300 was broader than that of ML. Up to 85th percentile, powder strength of L300 was lower than ML which was consistent with the better de-agglomeration of L300 at low flow rates. However, ~15% of L300 particles had higher powder strength than ML which likely to cause lower de-agglomeration for L300 at high air flow rates. Cohesive lactose powders formed matrices of non-homogenous powder strength. De-agglomeration of cohesive powders has been shown to be related to powder strength. This study provided new insights into powder de-agglomeration by a new approach for calculating powder strength distributions to better understand complex de-agglomeration behaviour.

  13. Application of powder rheometer to determine powder flow properties and lubrication efficiency of pharmaceutical particulate systems.

    Science.gov (United States)

    Navaneethan, Charu V; Missaghi, Shahrzad; Fassihi, Reza

    2005-10-19

    The objective of this study was to understand the behavior of particulate systems under different conditions of shear dynamics before and after granulation and to investigate the efficiency of powder lubrication. Three drug powders, metronidazole, colloidal bismuth citrate, and tetracycline hydrochloride, were chosen as model drugs representing noncohesive and cohesive powder systems. Each powder was individually granulated with microcrystalline cellulose and 5%PVP as a binder. One portion from each granulation was lubricated with different levels of magnesium stearate for 5 minutes. The powder characterization was performed on the plain powders, nonlubricated and lubricated granules using powder rheometer equipped with a helical blade rotating and moving under experimentally fixed set of parameters. The profiles of interaction during the force-distance measurements indicate that powder compresses, expands, and shears many times in a test cycle. Test profiles also clearly reveal existence of significant differences between cohesive and noncohesive powders. In all cases lubrication normalized the overall interactive nature of the powder by reducing peaks and valleys as observed from the profiles and reduced the frictional effect. The developed methods are easy to perform and will allow formulation scientists to better understand powder behavior and help in predicting potential impact of processing factors on particulate systems.

  14. Improving powder flow properties of a cohesive lactose monohydrate powder by intensive mechanical dry coating.

    Science.gov (United States)

    Zhou, Qi; Armstrong, Brian; Larson, Ian; Stewart, Peter J; Morton, David A V

    2010-02-01

    The objective of this study was to improve the cohesive lactose powder flowability. A cohesive lactose monohydrate powder was processed in either a tumbling blender or an intensive mechanical processor with either magnesium stearate or fumed silica. No substantial changes in particle size were detected by laser diffraction following either treatment. The untreated lactose sample exhibited very poor powder flow. Only limited improvements in powder flowability were indicated after the tumbling blending, intensive mechanical processing with the fumed silica or without additives. However, the intensive mechanical processing of the lactose sample with magnesium stearate demonstrated exceptionally large increases in both poured and tapped density as well as notable improvements in all powder flowability indicators examined. Our findings support the use of intensive mechanical processing technique as an effective method to coat cohesive pharmaceutical powders with selected additives, modify the surface nature of the particles, reduce the interparticle cohesive forces and hence improve powder flowability. The subtle differences in powder flow behaviour of lactose samples between the untreated and tumbling blended powders with magnesium stearate were only detected by the powder rheometer using its dynamic mode, indicating its potential advantages over traditional powder flow characterisation approaches. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association.

  15. Measurement of powder bed density in powder bed fusion additive manufacturing processes

    Science.gov (United States)

    Jacob, G.; Donmez, A.; Slotwinski, J.; Moylan, S.

    2016-11-01

    Many factors influence the performance of additive manufacturing (AM) processes, resulting in a high degree of variation in process outcomes. Therefore, quantifying these factors and their correlations to process outcomes are important challenges to overcome to enable widespread adoption of emerging AM technologies. In the powder bed fusion AM process, the density of the powder layers in the powder bed is a key influencing factor. This paper introduces a method to determine the powder bed density (PBD) during the powder bed fusion (PBF) process. A complete uncertainty analysis associated with the measurement method was also described. The resulting expanded measurement uncertainty, U PBD (k  =  2), was determined as 0.004 g · cm-3. It was shown that this expanded measurement uncertainty is about three orders of magnitude smaller than the typical powder bed density. This method enables establishing correlations between the changes in PBD and the direction of motion of the powder recoating arm.

  16. Facile synthesis and electrical switching properties of V{sub 2}O{sub 3} powders

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Haining; Liu, Dongqing, E-mail: dongqingliu@ymail.com; Cheng, Haifeng; Yang, Lixiang; Zhang, Chaoyang; Zheng, Wenwei

    2017-03-15

    Highlights: • Single crystal uniform V{sub 2}O{sub 3} powders have been synthesized without additional surfactant. • Powders were obtained in only 6 h. • Powders exhibit reversible phase transition properties. • Powders have excellent electrical switching properties with resistance changes as large as 10{sup 4}. - Abstract: V{sub 2}O{sub 3} powders were synthesized with mercaptoacetic acid (C{sub 2}H{sub 4}O{sub 2}S) as reducing agent and stabilizer via a facile hydrothermal approach. The crystalline structure, surface morphology, valence state of the derived V{sub 2}O{sub 3} powders were characterized via X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy. It was found that the ratio and reaction time played a duel role in the formation and morphology of the V{sub 2}O{sub 3} powders. The metal-insulator transition properties of V{sub 2}O{sub 3} powders were studied by the differential scanning calorimetry curve and variable temperature Raman spectra. The change in electrical resistance due to the metal-insulator transition was measured from 80 to 240 K using physical property measurement system. The results showed V{sub 2}O{sub 3} samples had excellent electrical switching properties with resistance changes as large as 10{sup 4}. This simple and fast synthesis approach makes the V{sub 2}O{sub 3} powders easily accessible for exploring their fundamental properties and potential applications in novel electronic devices.

  17. High shear treatment of concentrates and drying conditions influence the solubility of milk protein concentrate powders.

    Science.gov (United States)

    Augustin, Mary Ann; Sanguansri, Peerasak; Williams, Roderick; Andrews, Helen

    2012-11-01

    The solubility of milk protein concentrate (MPC) powders was influenced by the method used for preparing the concentrate, drying conditions, and the type of dryer used. Increasing total solids of the ultrafiltered concentrates (23% total solids, TS) by diafiltration to 25% TS or evaporation to 31% TS decreased the solubility of MPC powders (80-83% protein, w/w dry basis), with ultrafiltration followed by evaporation to higher total solids having the greater detrimental effect on solubility. High shear treatment (homogenisation at 350/100 bar, microfluidisation at 800 bar or ultrasonication at 24 kHz, 600 watts) of ultrafiltered and diafiltered milk protein concentrates prior to spray drying increased the nitrogen solubility of MPC powders (82% protein, w/w dry basis). Of the treatments applied, microfluidisation was the most effective for increasing nitrogen solubility of MPC powders after manufacture and during storage. Manufacture of MPC powders (91% protein, w/w dry basis) prepared on two different pilot-scale dryers (single stage or two stage) from milk protein concentrates (20% TS) resulted in powders with different nitrogen solubility and an altered response to the effects of microfluidisation. Microfluidisation (400, 800 and 1200 bar) of the concentrate prior to drying resulted in increased long term solubility of MPC powders that were prepared on a single stage dryer but not those produced on a two stage spray dryer. This work demonstrates that microfluidisation can be used as a physical intervention for improving MPC powder solubility. Interactions between the method of preparation and treatment of concentrate prior to drying, the drying conditions and dryer type all influence MPC solubility characteristics.

  18. Graphene: powder, flakes, ribbons, and sheets.

    Science.gov (United States)

    James, Dustin K; Tour, James M

    2013-10-15

    Graphene's unique physical and electrical properties (high tensile strength, Young's modulus, electron mobility, and thermal conductivity) have led to its nickname of "super carbon." Graphene research involves the study of several different physical forms of the material: powders, flakes, ribbons, and sheets and others not yet named or imagined. Within those forms, graphene can include a single layer, two layers, or ≤10 sheets of sp² carbon atoms. The chemistry and applications available with graphene depend on both the physical form of the graphene and the number of layers in the material. Therefore the available permutations of graphene are numerous, and we will discuss a subset of this work, covering some of our research on the synthesis and use of many of the different physical and layered forms of graphene. Initially, we worked with commercially available graphite, with which we extended diazonium chemistry developed to functionalize single-walled carbon nanotubes to produce graphitic materials. These structures were soluble in common organic solvents and were better dispersed in composites. We developed an improved synthesis of graphene oxide (GO) and explored how the workup protocol for the synthesis of GO can change the electronic structure and chemical functionality of the GO product. We also developed a method to remove graphene layers one-by-one from flakes. These powders and sheets of GO can serve as fluid loss prevention additives in drilling fluids for the oil industry. Graphene nanoribbons (GNRs) combine small width with long length, producing valuable electronic and physical properties. We developed two complementary syntheses of GNRs from multiwalled carbon nanotubes: one simple oxidative method that produces GNRs with some defects and one reductive method that produces GNRs that are less defective and more electrically conductive. These GNRs can be used in low-loss, high permittivity composites, as conductive reinforcement coatings on Kevlar

  19. Hygroscopic behavior of lyophilized acerola pulp powder

    Directory of Open Access Journals (Sweden)

    Luciana C. Ribeiro

    2016-03-01

    Full Text Available ABSTRACT Powder products are characterized by their practicality and long life. However, fruit powders have high hygroscopicity and tend to agglomerate due to its hydrophilic nature. The isotherms of equilibrium moisture content apply to the study of dehydrated food preservation potential. Acerola is a nutritionally rich fruit, with great economic and industrial potential. The objective of this study was to analyse acerola powder adsorption isotherms obtained by lyophilization and characterize the powder obtained from lyophilized acerola pulp. Analysis of hygroscopicity, solubility and degree of caking were performed. Isotherms were represented by the mathematical models of GAB, BET, Henderson and Oswin, at temperatures of 25, 35 and 45 °C. According to the results, the obtained powder showed hygroscopicity of 5.96 g of absorbed water 100g-1 of solids, solubility of 95.08% and caking of 14.12%. The BET model showed the best fit to the adsorption isotherms of the acerola pulp powder obtained by lyophilization. The obtained isotherm was of type III, with a "J" shape. There was an inversion of the effect of temperature on the isotherms of acerola powders.

  20. ESR powder line shape calculations

    Energy Technology Data Exchange (ETDEWEB)

    Vitko, J. Jr.; Huddleston, R.E.

    1976-05-01

    A program has been developed for computing the ESR spectrum of a collection of randomly oriented spins subject only to an electronic Zeeman interaction and having a Lorentzian single crystal line shape. Other single crystal line shapes, including numerical solutions of the Bloch equations, can be accommodated with minor modifications. The program differs in several features from those existing elsewhere, thus enabling one to study saturation effects, over-modulation effects, both absorptive and dispersive signals, and second and higher order derivative signals.

  1. Fire hazard of titanium powder layers mixed with inert nano TiO2 powder.

    Science.gov (United States)

    Yuan, Chunmiao; Cai, Jingzhi; Amyotte, Paul; Li, Chang; Bu, Yajie; Liu, Kangfu; Li, Gang

    2017-12-06

    Metallic dust layers are highly sensitive to ignition from common ignition sources, even when mixed with high percentages of inert solids. In turn, dust layer fires are a potential ignition source for dust explosions or other damaging fires. Flame spread velocity (FSV), as a potential parameter for evaluating fire hazard, was investigated for titanium powder layers mixed with inert nano TiO2 powder in both natural convection and in forced airflow conditions. Increased mass percentage of nano TiO2 powder decreased FSV of Ti powder mixtures as expected. The mixing ratio of nano TiO2 to fully suppress layer fires was 80% and 90% for micro and nano Ti powder, respectively. Mechanisms governing flame spread across a layer of nano Ti powder differed from those of a layer of micro Ti powder. FSV in no airflow conditions was higher than in aided airflow for micro Ti powder because conduction was the dominant heat transfer mechanism. However, FSV in no airflow was lower than in opposed airflow for nano Ti powder because convection/radiation was the dominant heat transfer mechanism. A fly fire phenomenon contributed to greater FSVs and higher fire hazard with nano Ti powder mixtures under aided airflow conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Use of whey powder and skim milk powder for the production of fermented cream

    Directory of Open Access Journals (Sweden)

    Ceren AKAL

    2016-01-01

    Full Text Available Abstract This study is about the production of fermented cream samples having 18% fat by addition of starter cultures. In order to partialy increase non-fat solid content of fermented cream samples, skim milk powder and demineralized whey powder in two different rates (50% and 70% were used. Samples were analyzed for changes in their biochemical and physicochemical properties (total solid, ash, fat, titratable acidity, pH value, total nitrogen, viscosity, tyrosine, acid number, peroxide and diacetyl values during 29-day of storage period. Samples tested consisted of 7 different groups; control group (without adding any powder, skim milk powder, 50% demineralized whey powder and 70% demineralized whey powder samples were in two different addition rate (2% and 4%. Also samples were analyzed for sensory properties. According to the results obtained, the addition of milk powder products affected titratable acidity and tyrosine values of fermented cream samples. Although powder addition and/or storage period didn’t cause significant variations in total solid, ash, fat, pH value, viscosity, acid number, peroxide, tyrosine and diacetyl values; sensory properties of fermented cream samples were influenced by both powder addition and storage period. Fermented cream containing 2% skim milk powder gets the top score of sensory evaluation among the samples.

  3. Computer simulation tests of optimized neutron powder diffractometer configurations

    Energy Technology Data Exchange (ETDEWEB)

    Cussen, L.D., E-mail: Leo@CussenConsulting.com [Cussen Consulting, 23 Burgundy Drive, Doncaster 3108 (Australia); Lieutenant, K., E-mail: Klaus.Lieutenant@helmholtz-berlin.de [Helmholtz Zentrum Berlin, Hahn-Meitner Platz 1, 14109 Berlin (Germany)

    2016-06-21

    Recent work has developed a new mathematical approach to optimally choose beam elements for constant wavelength neutron powder diffractometers. This article compares Monte Carlo computer simulations of existing instruments with simulations of instruments using configurations chosen using the new approach. The simulations show that large performance improvements over current best practice are possible. The tests here are limited to instruments optimized for samples with a cubic structure which differs from the optimization for triclinic structure samples. A novel primary spectrometer design is discussed and simulation tests show that it performs as expected and allows a single instrument to operate flexibly over a wide range of measurement resolution.

  4. Particle size changes in unsealed mineral trioxide aggregate powder.

    Science.gov (United States)

    Ha, William N; Kahler, Bill; Walsh, Laurence James

    2014-03-01

    Mineral trioxide aggregate (MTA) is commonly supplied in 1-g packages of powder that are used by some clinicians across several treatments against the manufacturer's instructions. ProRoot MTA cannot be resealed after opening, whereas MTA Angelus has a resealable lid. This study assessed changes in particle size distribution once the packaging had been opened. Fresh ProRoot MTA and MTA Angelus powder were analyzed by using laser diffraction and scanning electron microscopy and compared with powder from packages that had been opened once and kept in storage for 2 years. The ProRoot packet was folded over, whereas the MTA Angelus jar had the lid twisted back to its original position. After 2 years, ProRoot MTA powder showed a 6-fold increase in particle size (lower 10% from 1.13 to 4.37 μm, median particle size from 1.99 to 12.87 μm, and upper 10% from 4.30 to 34.67 μm), with an accompanying 50-fold change in particle surface area. MTA Angelus showed only a 2-fold increase in particle size (4.15 to 8.32 μm, 12.72 to 23.79 μm, and 42.66 to 47.91 μm, respectively) and a 2-fold change in particle size surface area. MTA reacts with atmospheric moisture, causing an increase in particle size that may adversely affect the properties and shelf life of the material. Smaller particles have a greater predisposition to absorb moisture. Single-use systems are advised. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Properies of binder systems containing cement, fly ash, and limestone powder

    Directory of Open Access Journals (Sweden)

    Krittiya Kaewmanee

    2014-10-01

    Full Text Available Fly ash and limestone powder are two major widely available cement replacing materials in Thailand. However, the current utilization of these materials is still not optimized due to limited information on properties of multi-binder systems. This paper reports on the mechanical and durability properties of mixtures containing cement, fly ash, and limestone powder as single, binary, and ternary binder systems. The results showed that a single binder system consisting of only cement gave the best carbonation resistance. A binary binder system with fly ash exhibited superior performances in long-term compressive strength and many durability properties except carbonation and magnesium sulfate resistances, while early compressive strength of a binary binder system with limestone powder was excellent. The ternary binder system, taking the most benefit of selective cement replacing materials, yielded, though not the best, satisfactory performances in almost all properties. Thus, the optimization of binders can be achieved through a multi-binder system.

  6. Hydrothermal synthesis of fine oxide powders

    Indian Academy of Sciences (India)

    The authors describe. hydrothermal decomposition,; hydrothermal metal oxidation,; hydrothermal reaction,; hydrothermal precipitation and hydrothermal hydrolysis,; hydrothermal electrochemical,; reactive electrode submerged arc,; hydrothermal microwave,; hydrothermal sonochemical,. etc and also ideal and real powders ...

  7. 30 CFR 56.6901 - Black powder.

    Science.gov (United States)

    2010-07-01

    ...) Containers of black powder shall be— (1) Nonsparking; (2) Kept in a totally enclosed cargo space while being transported by a vehicle; (3) Securely closed at all times when— (i) Within 50 feet of any magazine or open...

  8. Toxicology evaluation of selenium protein powder

    Directory of Open Access Journals (Sweden)

    Qin Shunyi

    2017-01-01

    Full Text Available The experiment was conducted to evaluate the safety of selenium protein powder, a novel organic selenium nutritional supplement, and reported corresponding data and results based on a series of toxicological tests. It was examined to evaluate oral acute toxicity by median lethal dose test and mutagenic potential by bone marrow cell micronucleus test and sperm abnormality test using Kun-Ming mice. The results showed that the oral LD50 of selenium protein powder exceeded 31.25 g/kg body weight in mice. No mutagenicity was found by mouse bone marrow cell micronucleus test and mouse sperm abnormality test. The results suggested greater safety of selenium protein powder as a nutritional selenium supplement, and selenium protein powder has the potential for development and application in food systems or functional foods.

  9. Surface chemistry and microscopy of food powders

    Science.gov (United States)

    Burgain, Jennifer; Petit, Jeremy; Scher, Joël; Rasch, Ron; Bhandari, Bhesh; Gaiani, Claire

    2017-12-01

    Despite high industrial and scientific interest, a comprehensive review of the surface science of food powders is still lacking. There is a real gap between scientific concerns of the field and accessible reviews on the subject. The global description of the surface of food powders by multi-scale microscopy approaches seems to be essential in order to investigate their complexity and take advantage of their high innovation potential. Links between these techniques and the interest to develop a multi-analytical approach to investigate scientific questions dealing with powder functionality are discussed in the second part of the review. Finally, some techniques used in others fields and showing promising possibilities in the food powder domain will be highlighted.

  10. Porous Nb-Ti based alloy produced from plasma spheroidized powder

    Directory of Open Access Journals (Sweden)

    Qijun Li

    Full Text Available Spherical Nb-Ti based alloy powder was prepared by the combination of plasma spheroidization and mechanical alloying. Phase constituents, microstructure and surface state of the powder, and pore characteristics of the resulting porous alloy were investigated. The results show that the undissolved W and V in the mechanically alloyed powder is fully alloyed after spheroidization, and single β phase is achieved. Particle size of the spheroidized powder is in the range of 20–110 μm. With the decrease of particle size, a transformation from typical dendrite solidification structure to fine cell microstructure occurs. The surface of the spheroidized powder is coated by a layer of oxides consisting mainly of TiO2 and Nb2O5. Probabilities of sinter-neck formation and particle coalescence increases with increasing sintering temperature. Porous skeleton with relatively homogeneous pore distribution and open pore channel is formed after vacuum sintering at 1700 °C, and the porosity is 32%. The sintering kinetic analysis indicates that grain boundary diffusion is the primary mass transport mechanism during sintering process. Keywords: Powder metallurgy, Nb-Ti based alloy, Porous material, Mechanical alloying, Plasma spheroidizing, Solidification microstructure

  11. Multi-Layered Effects of Fe on EMI Shielding of Sn-Al Hotel Architectural Powder

    Directory of Open Access Journals (Sweden)

    Hung Fei-Shuo

    2016-01-01

    Full Text Available No evident effect in shielding efficiency is observed when the electromagnetic wave-absorbing coating materials were applied in single layers because of the dispersing nature of the powder. When increased to two-layer coating, shielding effects were evident at both high and low frequencies, with greater shielding efficiency at low frequencies over high frequencies. It is worth noting that when increased to three-layer coating, as the weight percentage of powdered Fe increased from 5% to 8% , the shielding efficiency of the powdered-Fe composite material was raised to −35 dB This shows that, as the weight percentage gets higher, the powder shows the resonance phenomenon of permeability spectrum, and at high frequencies, the electromagnetic wave shielding efficiency of the composite materials were greatly increased. As the weight percentage of the powered Fe were increased to 8% , we were unable to spread the powder evenly in the epoxy because of the dispersing characteristic in the electromagnetic properties of Fe and the anisotropic and heterogeneous nature of a powered composite material. During production, the powder aggregates often resulted in greater heterogeneity in the materials and consequently, lowered shielding efficiency at 3GHz.

  12. Flow rate and flow equation of pharmaceutical free-flowable powder excipients.

    Science.gov (United States)

    Sklubalová, Zdenka; Zatloukal, Zdenek

    2013-02-01

    Basic aspect of powder handling is powder flow which depends on mechanical properties of the solid material. This experimental work presents the results of flowability testing of the free-flowable particle size fraction of 0.0250-0.0315 cm of five powder excipients. The single-point determination of the mass flow rate from a cylindrical, flat-bottomed hopper was primarily influenced by the diameter of a circular orifice. The significant effect of the orifice height was also noted. Increasing the orifice height, the flow under gravity is directed resulting in the sudden acceleration of the flow rate. The critical zone relates to the orifice diameter. The multi-point determination of flowability employed the actual parameters of the flow equation which allows the prediction of the mass flow rate. The precision of the prediction was the basic criterion in optimization of the orifice geometry. Based on the results, the orifice height of 1.6 cm can be recommended for the correction of faster powder flow. For the slower powder flow, an orifice height of 0.2 cm can be used alternatively. In conclusion, the information about the orifice height used should be referred to whenever test the powder flowability and compare the results.

  13. Characterization of temperature-dependent optical material properties of polymer powders

    Energy Technology Data Exchange (ETDEWEB)

    Laumer, Tobias [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany); Stichel, Thomas; Bock, Thomas; Amend, Philipp [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany); Schmidt, Michael [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); University of Erlangen-Nürnberg, Institute of Photonic Technologies, 91052 Erlangen (Germany); SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany)

    2015-05-22

    In former works, the optical material properties of different polymer powders used for Laser Beam Melting (LBM) at room temperature have been analyzed. With a measurement setup using two integration spheres, it was shown that the optical material properties of polymer powders differ significantly due to multiple reflections within the powder compared to solid bodies of the same material. Additionally, the absorption behavior of the single particles shows an important influence on the overall optical material properties, especially the reflectance of the powder bed. Now the setup is modified to allow measurements at higher temperatures. Because crystalline areas of semi-crystalline thermoplastics are mainly responsible for the absorption of the laser radiation, the influence of the temperature increase on the overall optical material properties is analyzed. As material, conventional polyamide 12 and polypropylene as new polymer powder material, is used. By comparing results at room temperature and at higher temperatures towards the melting point, the temperature-dependent optical material properties and their influence on the beam-matter interaction during the process are discussed. It is shown that the phase transition during melting leads to significant changes of the optical material properties of the analyzed powders.

  14. Pyrolysis characteristics of the mixture of printed circuit board scraps and coal powder.

    Science.gov (United States)

    Hao, Juan; Wang, Haifeng; Chen, Shuhe; Cai, Bin; Ge, Linhan; Xia, Wencheng

    2014-10-01

    Thermogravimetric (TG) analysis and infrared spectroscopy were used to analyze the pyrolysis characteristics of printed circuit board scraps (PCBs), coal powder and their mixtures under nitrogen atmosphere. The experimental results show that there is a large difference between waste PCBs and coal powder in pyrolysis processing. The pyrolysis properties of the mixing samples are the result of interaction of the PCBs and coal powder, which is influenced by the content of mixture. The degree of pyrolysis and pyrolysis properties of the mixture are much better than that of the single component. The TG and the differential thermogravimetric (DTG) curves of the PCBs mixed with coal powder move towards the high-temperature zone with increasing amount of coal powder and subsequently the DTG peak also becomes wider. The Coats-Redfern integral method was used to determine the kinetic parameters of pyrolysis reaction mechanism with the different proportion of mixture. The gas of pyrolysis mainly composes of CO2, CO, H2O and some hydrocarbon. The bromide characteristic absorption peak has been detected obviously in the pyrolysis gas of PCBs. On the contrary, the absorption peak of the bromide is not obvious in pyrolysis gas of the PCBs samples adding 40% coal powder. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  16. Powder Characterization and Optimization for Additive Manufacturing

    OpenAIRE

    Cordova, Laura; Campos, Mónica; Tinga, Tiedo

    2017-01-01

    Achieving the optimal quality for Additive Manufactured (AM) parts does not only depend on setting the right process parameters. Material feedstock also plays an important role when aiming for high performance products. The metal AM processes that are most applicable to industry, Powder Bed Fusion and Directed Energy Deposition, use metal powder as raw material. Therefore, controlling the quality and correctly characterizing the particles used in the process is a key step to successfully appl...

  17. Advanced powder metallurgy aluminum alloys and composites

    Science.gov (United States)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  18. Powder metallurgy in aerospace research: A survey

    Science.gov (United States)

    Blakeslee, H. W.

    1971-01-01

    The various techniques by which powders can be produced, as pure metals or as alloys, are discussed; the methods by which these powders can be formed into the final parts are explained as well as further processing that may be necessary to meet specific requirements. The NASA developments are detailed, and references are provided for those who wish to obtain further information characteristic of any methodology.

  19. Powder diffraction studies using anomalous dispersion

    Energy Technology Data Exchange (ETDEWEB)

    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]).

  20. Powder diffraction studies using anomalous dispersion

    Energy Technology Data Exchange (ETDEWEB)

    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}).

  1. Antibacterial effect of bioactive glass in combination with powdered enamel and dentin

    Directory of Open Access Journals (Sweden)

    Prabhakar A

    2010-01-01

    Full Text Available Background and Objectives: In endodontics, various intracanal medications have been advocated to eliminate bacteria after root canal instrumentation. A recent study has revealed that addition of powdered dentin to bioactive glass (BAG led to increased glass dissolution, and an increased antibacterial efficacy. Therefore, the present study was undertaken to compare the effect of enamel and dentin powder on the antibacterial efficacy of a commercially available BAG. Materials and Methods: Dentin blocks (dbs were prepared from single rooted human teeth. These dbs were infected with Enterococcus faecalis for two weeks in Tryptic Soy Broth (TSB, while negative controls were kept in sterile TSB. In group I, the infected dbs were filled with BAG, in group II with BAG + Enamel powder and group III with BAG + Dentin powder. Dentin samples were harvested from the dbs and cultured. Statistical Analysis: Kruskal-Wallis ANOVA was used for multiple group comparison followed by Scheffe′s post hoc test for pair-wise comparisons. Results: All the combinations of BAG evaluated significantly reduced the bacterial counts compared to the control group. However, at the end of 24 hours, three days, and five days BAG + Dentin powder showed significant reduction ( P < 0.01 in bacterial counts compared to the other experimental groups. Conclusion: Among the various materials evaluated, it appeared that though BAG exhibits antimicrobial efficacy, the addition of powdered enamel and dentin in aqueous suspension definitely enhanced this property. However, the addition of enamel powder BAG did not significantly alter its antimicrobial efficacy compared to BAG + dentin powder.

  2. Efficacy of a new pulmonary cyclosporine a powder formulation for prevention of transplant rejection in rats

    NARCIS (Netherlands)

    Zijlstra, Gerrit S.; Wolting, Joske; Prop, Jochum; Petersen, Arjen H.; Hinrichs, Wouter L.J.; Uges, Donald R.A.; Kerstjens, Huib A.M.; van der Bij, Wim; Frijlink, Henderik W.

    2009-01-01

    Background: The aim of this pilot study was to determine the pharmacokinetics of cyclosporine A powder for inhalation (iCsA) and its rejection prevention efficacy in an experimental lung transplantation model in rats. Methods: Single-dose pharmacokinetics (10 mg/kg) of pulmonary and orally

  3. Investigation of milling processes of semiconductor zinc oxide nanostructured powders by X-ray phase analysis

    Science.gov (United States)

    Pronin, I. A.; Averin, I. A.; Yakushova, N. D.; Vishnevskaya, G. V.; Sychov, M. M.; Moshnikov, V. A.; Terukov, E. I.

    2017-11-01

    The processes of mechanical activation of nanostructured zinc oxide powders are investigated by X-ray phase analysis. It was determined, that samples remain in a single phase state during the milling process. The particle size decreases according to the linear time law, and microstrains grow parabolically.

  4. Plasma spheroidization of nickel powders in a plasma reactor

    Indian Academy of Sciences (India)

    The technique involves injection of the powder into a plasma flame, melting, acceleration of the powder particles, impact and bonding with the substrate. Feedstock powders of metals, alloys and ceramics for thermal spray applications have to meet several requirements. Particle shape, size and its distribution, powder flow ...

  5. Frontal Dynamics of Powder Snow Avalanches

    Science.gov (United States)

    Louge, M. Y.; Carroll, C. S.; Turnbull, B.

    2012-04-01

    We model the dynamics of the head of dilute powder snow avalanches sustained by a massive frontal blow-out, arising as a weakly cohesive snow cover is fluidized by the very pore pressure gradients that the avalanche induces within the snow pack. Such material eruption just behind the front acts as a source of denser fluid thrust into a uniform ambient air flow at high Reynolds number. In such "eruption current", fluidization depth is inversely proportional to a bulk Richardson number representing avalanche height. By excluding situations in which the snow cover is not fluidized up to its free surface, we derive a criterion combining snow pack friction and density indicating which avalanches can produce a sustainable powder cloud. A mass balance involving snow cover and powder cloud sets avalanche height and mean density. By determining which solution of the mass balance is stable, we find that avalanches reach constant growth and acceleration rates for fixed slope and avalanche width. Under these conditions, we calculate the fraction of the fluidized cover that is actually scoured and blown-out into the cloud, and deduce from a momentum balance on the head that the avalanche accelerates at a rate only 14% of the gravitational component along the flow. We also calculate how far a powder cloud travels until its mean density becomes constant. Finally, we show that the dynamics of powder snow avalanches are crucially affected by the rate of change of their width, for example by reaching an apparent steady speed as their channel widens. If such widening is rapid, or if slope inclination vanishes, we calculate where and how powder clouds collapse. Predictions agree well with observations of powder snow avalanches carried out at the Vallee de la Sionne (Switzerland).

  6. Pure insulin highly respirable powders for inhalation.

    Science.gov (United States)

    Balducci, Anna Giulia; Cagnani, Stefano; Sonvico, Fabio; Rossi, Alessandra; Barata, Pedro; Colombo, Gaia; Colombo, Paolo; Buttini, Francesca

    2014-01-23

    The aim of the present research was to investigate the possibility to obtain by spray drying an insulin pulmonary powder respirable and stable at room temperature without the use of excipients. Several insulin spray-dried powders were prepared with or without the addition of excipients (mannitol, bovine serum albumin, aspartic acid) from water dispersions or from acidic aqueous solutions. Each formulation was characterized using laser diffraction, scanning electron microscopy and in vitro aerosol performance with a Turbospin DPI device. Stability was assessed by the quantification of impurities with a molecular mass greater than that of insulin (HMWP) and related proteins (A21+ORP). Insulin powders prepared without excipients from an acid solution showed a shrivelled, raisin-like shape of non-aggregated microparticles and a high respirability (FPF>65%). The optimal result with respect to respirability and stability was reached when the pH of the insulin acetic acid solution to spray dry was adjusted at pH 3.6 with ammonium hydroxide. The median volume diameter of the obtained powder was 4.04 μm, insulin content 95%, emitted dose of 89.5%, MMAD 1.79 μm and fine particle fraction of 83.6%. This powder was stable at room temperature over a period of eighteen months with respect to the content of A21+ORP. As far as the HMWP content was concerned, the powder complied with the specification limits for a period of five months. The insulin acetic powder opens up the possibility of a more effective pulmonary therapy less dependent on refrigerated storage. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

  8. Methods for production of aluminium powders and their application fields

    Energy Technology Data Exchange (ETDEWEB)

    Gopienko, V.G.; Kiselev, V.P.; Zobnina, N.S. (Vsesoyuznyj Nauchno-Issledovatel' skij i Proektnyj Inst. Alyuminievoj, magnievoj i ehlektrodnoj promyshlennosti (USSR))

    1984-12-01

    Different types of powder products made of alluminium and its alloys (powder, fine powders, granules and pastes) as well as their basic physicochemical properties are briefly characterized. The principle methods for alluminium powder production are outlined: physicochemical methods, the melt spraying by compressed gas being the mostly developed among them, and physico-mechanical ones. Main application spheres for powder productions of aluminium and its alloys are reported in short.

  9. PRODUCTION OF POROUS POWDER MATERIALS OF SPHERICAL POWDERS OF CORROSION-RESISTANT STEEL

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevskij

    2012-01-01

    Full Text Available Production of porous powder materials from spherical powders of corrosion-resistant steel 12Х18н10Т with formation at low pressures 120–140 mpa in the mold with the subsequent activated sintering became possible due to increase of duration of process of spattering and formation of condensate particles (Si–C or (Mo–Si on surface.

  10. Plasma synthesis of lithium based intercalation powders for solid polymer electrolyte batteries

    Science.gov (United States)

    Kong, Peter C [Idaho Falls, ID; Pink, Robert J [Pocatello, ID; Nelson, Lee O [Idaho Falls, ID

    2005-01-04

    The invention relates to a process for preparing lithium intercalation compounds by plasma reaction comprising the steps of: forming a feed solution by mixing lithium nitrate or lithium hydroxide or lithium oxide and the required metal nitrate or metal hydroxide or metal oxide and between 10-50% alcohol by weight; mixing the feed solution with O.sub.2 gas wherein the O.sub.2 gas atomizes the feed solution into fine reactant droplets, inserting the atomized feed solution into a plasma reactor to form an intercalation powder; and if desired, heating the resulting powder to from a very pure single phase product.

  11. Cosmetic powder suspensions in compliant, fingerprintlike contacts.

    Science.gov (United States)

    Timm, K; Myant, C; Spikes, H A; Schneider, M; Ladnorg, T; Grunze, M

    2011-09-01

    Cosmetic powders are regularly employed in skin creams and cosmetic formulations to improve performance and enhance skin feel. A previous study investigated the effect of particle concentration and size on the lubricating properties of powder suspensions in smooth, compliant contacts [Timm et al., Tribol. Int. (2011)]. In this paper the tribological properties of cosmetic powder suspensions are investigated in compliant contacts having model fingerprintlike surface topography. Friction coefficients were measured for a series of powder suspensions with varying particle size and concentration in a polydimethylsiloxane (PDMS)/PDMS contact. A commercial tribometer (MTM, PCS Instruments) was employed to measure friction as a function of rubbing time (20 min), under pure sliding (50 mm/s) and low load (0.5 N) conditions. Compared to results using smooth surfaces, it was clear that surface topography has a pronounced affect on the time-dependent tribological behavior of the cosmetic powder suspensions studied. A two-stage friction coefficient versus time curve was observed. By varying the particle size and concentration it was shown that the duration and magnitude of each stage can be controlled.

  12. Polymer powders for selective laser sintering (SLS)

    Science.gov (United States)

    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.

  13. Formulation Design of Dry Powders for Inhalation.

    Science.gov (United States)

    Weers, Jeffry G; Miller, Danforth P

    2015-10-01

    Drugs for inhalation are no longer exclusively highly crystalline small molecules. They may also be amorphous small molecules, peptides, antibodies, and myriad types of engineered proteins. The evolution of respiratory therapeutics has created a need for flexible formulation technologies to engineer respirable particles. These technologies have enabled medicinal chemists to focus on molecular design without concern regarding compatibility of physicochemical properties with traditional, blend-based technologies. Therapeutics with diverse physicochemical properties can now be formulated as stable and respirable dry powders. Particle engineering technologies have also driven the deployment of new excipients, giving formulators greater control over particle and powder properties. This plays a key role in enabling efficient delivery of drugs to the lungs. Engineered powder and device combinations enable aerosols that largely bypass the mouth and throat, minimizing the inherent variability among patients that arises from differences in oropharyngeal and airway anatomies and in breathing profiles. This review explores how advances among molecules, particles, and powders have transformed inhaled drug product development. Ultimately, this scientific progress will benefit patients, enabling new classes of therapeutics to be formulated as dry powder aerosols with improved efficacy, reduced variability and side effects, and improved patient adherence. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. Investigation of the potential for direct compaction of a fine ibuprofen powder dry-coated with magnesium stearate.

    Science.gov (United States)

    Qu, Li; Zhou, Qi Tony; Gengenbach, Thomas; Denman, John A; Stewart, Peter J; Hapgood, Karen P; Gamlen, Michael; Morton, David A V

    2015-05-01

    Intensive dry powder coating (mechanofusion) with tablet lubricants has previously been shown to give substantial powder flow improvement. This study explores whether the mechanofusion of magnesium stearate (MgSt), on a fine drug powder can substantially improve flow, without preventing the powder from being directly compacted into tablets. A fine ibuprofen powder, which is both cohesive and possesses a low-melting point, was dry coated via mechanofusion with between 0.1% and 5% (w/w) MgSt. Traditional low-shear blending was also employed as a comparison. No significant difference in particle size or shape was measured following mechanofusion. For the low-shear blended powders, only marginal improvement in flowability was obtained. However, after mechanofusion, substantial improvements in the flow properties were demonstrated. Both XPS and ToF-SIMS demonstrated high degrees of a nano-scale coating coverage of MgSt on the particle surfaces from optimized mechanofusion. The study showed that robust tablets were produced from the selected mechanofused powders, at high-dose concentration and tablet tensile strength was further optimized via addition of a Polyvinylpyrrolidone (PVP) binder (10% w/w). The tablets with the mechanofused powder (with or without PVP) also exhibited significantly lower ejection stress than those made of the raw powder, demonstrating good lubrication. Surprisingly, the release rate of drug from the tablets made with the mechanofused powder was not retarded. This is the first study to demonstrate such a single-step dry coating of model drug with MgSt, with promising flow improvement, flow-aid and lubrication effects, tabletability and also non-inhibited dissolution rate.

  15. Synthesis of yttria powders by electrospray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Rulison, A.J.; Flagan, R.C. (California Inst. of Technology, Pasadena, CA (United States))

    1994-12-01

    Electrospray atomization of high-concentration ([approximately]400 g/L) chemical precursor solutions was applied to the synthesis of yttria powders. Conditions were found which led to high-quality powders, composed of dense, spheroidal, submicrometer, and nanocrystalline oxide particles. The precursor solutions were hydrated yttrium nitrates dissolved in n-propyl alcohol at concentrations ranging from 44.1 to 455 g/L. Electrospray atomization produced submicrometer precursor droplets which were dispersed in air and carried through an electric furnace for thermal decomposition at 500 C for several seconds residence time. X-ray powder diffraction patterns indicated the expected cubic phase. Transmission electron micrographs showed that the particle structure varied with solution composition, ranging from hollow, inflated spheres for 6-hydrated nitrates to dense spheroids for 5-hydrated nitrates. The use of 6-hydrated nitrates in the solutions appeared to form particle surfaces which were impermeable to alcohol vapor evolved during thermal decomposition, leading to hollow, inflated spheres.

  16. Red man syndrome caused by vancomycin powder.

    Science.gov (United States)

    Nagahama, Yasunori; VanBeek, Marta J; Greenlee, Jeremy D W

    2018-02-01

    Red man syndrome (RMS) is a well-known hypersensitivity reaction caused by intravenous administration of vancomycin, with symptoms ranging from flushing, erythematous rash, pruritus, mild to profound hypotension, and even cardiac arrest. RMS has not previously been described from local application of vancomycin powder in a surgical wound, a technique increasingly utilized for infection prophylaxis in many surgical disciplines including neurosurgery. We describe the first reported case of RMS as a result of local intra-wound application of vancomycin powder for infection prophylaxis. A 73-year-old male with a history of Parkinson's disease underwent 2-stage deep brain stimulation implantation surgeries. Vancomycin powder was applied locally in the surgical wounds for infection prophylaxis during both of the surgeries. The patient developed a well-demarcated, geometric erythematous pruritic rash following the second surgery that was clinically diagnosed as RMS and resolved without sequelae. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Recent analytical developments for powder characterization

    Science.gov (United States)

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

    2015-07-01

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

  18. Enery Efficient Press and Sinter of Titanium Powder for Low-Cost Components in Vehicle Applications

    Energy Technology Data Exchange (ETDEWEB)

    Thomas Zwitter; Phillip Nash; Xiaoyan Xu; Chadwick Johnson

    2011-03-31

    This is the final technical report for the Department of Energy NETL project NT01931 Energy Efficient Press and Sinter of Titanium Powder for Low-Cost Components in Vehicle Applications. Titanium has been identified as one of the key materials with the required strength that can reduce the weight of automotive components and thereby reduce fuel consumption. Working with newly developed sources of titanium powder, Webster-Hoff will develop the processing technology to manufacture low cost vehicle components using the single press/single sinter techniques developed for iron based powder metallurgy today. Working with an automotive or truck manufacturer, Webster-Hoff will demonstrate the feasibility of manufacturing a press and sinter titanium component for a vehicle application. The project objective is two-fold, to develop the technology for manufacturing press and sinter titanium components, and to demonstrate the feasibility of producing a titanium component for a vehicle application. The lowest cost method for converting metal powder into a net shape part is the Powder Metallurgy Press and Sinter Process. The method involves compaction of the metal powder in a tool (usually a die and punches, upper and lower) at a high pressure (up to 60 TSI or 827 MPa) to form a green compact with the net shape of the final component. The powder in the green compact is held together by the compression bonds between the powder particles. The sinter process then converts the green compact to a metallurgically bonded net shape part through the process of solid state diffusion. The goal of this project is to expand the understanding and application of press and sinter technology to Titanium Powder applications, developing techniques to manufacture net shape Titanium components via the press and sinter process. In addition, working with a vehicle manufacturer, demonstrate the feasibility of producing a titanium component for a vehicle. This is not a research program, but rather a

  19. Metal vapor micro-jet controls material redistribution in laser powder bed fusion additive manufacturing.

    Science.gov (United States)

    Ly, Sonny; Rubenchik, Alexander M; Khairallah, Saad A; Guss, Gabe; Matthews, Manyalibo J

    2017-06-22

    The results of detailed experiments and finite element modeling of metal micro-droplet motion associated with metal additive manufacturing (AM) processes are presented. Ultra high speed imaging of melt pool dynamics reveals that the dominant mechanism leading to micro-droplet ejection in a laser powder bed fusion AM is not from laser induced recoil pressure as is widely believed and found in laser welding processes, but rather from vapor driven entrainment of micro-particles by an ambient gas flow. The physics of droplet ejection under strong evaporative flow is described using simulations of the laser powder bed interactions to elucidate the experimental results. Hydrodynamic drag analysis is used to augment the single phase flow model and explain the entrainment phenomenon for 316 L stainless steel and Ti-6Al-4V powder layers. The relevance of vapor driven entrainment of metal micro-particles to similar fluid dynamic studies in other fields of science will be discussed.

  20. In-house characterization of protein powder

    DEFF Research Database (Denmark)

    Hartmann, Christian Grundahl; Harris, Pernille; Ståhl, Kenny

    2011-01-01

    Collecting protein powder diffraction data on standard in-house powder diffractometers requires careful handling of the samples. Specially designed sample holders combined with optimized collimation were found to be the key factors in improving the data quality and reducing the data collection time....... For safe identification of the crystal form the experimental patterns have to be compared with patterns calculated from known crystal structures. Very good agreement with Protein Data Bank data was obtained after including corrections for background, unit cell parameters, disordered bulk...

  1. Hypolipidemic effects of fenugreek seed powder

    Directory of Open Access Journals (Sweden)

    Abu Saleh M. Moosa, Mamun Ur Rashid, A.Z.S. Asadi, Nazma Ara, M. Mojib Uddin and A. Ferdaus

    2006-12-01

    Full Text Available Effects of fenugreek (Trigonella foenugraecum Linn on serum lipid profile in hypercholesteremic type 2 diabetic patients were studied. Administration of fenugreek seed powder of 25 gm orally twice daily for 3 weeks and 6 weeks produces significant (P<0.001 reduction of serum total cholesterol, triacylglyceride and LDL-cholesterol in hypercholesteremic group but the change of serum HDL-cholesterol was not significant. On other hand, changes of lipid profile in hypercholesteremic type 2 diabetic patients without fenugreek were not significant (P<0.001. The present study suggests that fenugreek seed powder would be considered as effective agent for lipid lowering purposes.

  2. Desensitizing nano powders to electrostatic discharge ignition

    Energy Technology Data Exchange (ETDEWEB)

    Steelman, Ryan [Texas Tech Univ., Lubbock, TX (United States). Dept. of Mechanical Engineering; Clark, Billy [Texas Tech Univ., Lubbock, TX (United States). Dept. of Mechanical Engineering; Pantoya, Michelle L. [Texas Tech Univ., Lubbock, TX (United States). Dept. of Mechanical Engineering; Heaps, Ronald J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Daniels, Michael A. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    Electrostatic discharge (ESD) is a main cause for ignition in powder media ranging from grain silos to fireworks. Nanoscale particles are orders of magnitude more ESD ignition sensitive than their micron scale counterparts. This study shows that at least 13 vol. % carbon nanotubes (CNT) added to nano-aluminum and nano-copper oxide particles (nAl + CuO) eliminates ESD ignition sensitivity. The CNT act as a conduit for electric energy and directs electric charge through the powder to desensitize the reactive mixture to ignition. For nanoparticles, the required CNT concentration for desensitizing ESD ignition acts as a diluent to quench energy propagation.

  3. A mechanistic analysis of bulk powder caking

    Science.gov (United States)

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

    2013-06-01

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

  4. Safety consideration when handling metal powders

    CSIR Research Space (South Africa)

    Benson, JM

    2012-03-01

    Full Text Available . No compressed air hoses should be used � The dust extraction or venting system must be designed to convey powders at concentrations below their MEC. Eliminate all sources of ignition in powder-handling areas � No smoking or smoking materials, including..., and this gives some perspective on the immensity of the hazard. Aluminium dust particles produced during the diecasting process were collected by a dust extraction system for recycling and were stored in a trap outside the factory. A spark ignited an initial...

  5. Deposition and clearance of inhaled {sup 18}FDG powder in patients with chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Yanai, M.; Sasaki, H. [Tohoku Univ. School of Medicine, Dept. of Geriatric Medicine, Sendai (Japan); Hatazawa, J.; Ojima, F.; Itoh, M.; Ido, T. [Tohoku Univ. School of Medicine, Cyclotron and Radioisotope Center, Sendai (Japan)

    1998-12-31

    As freon is limited in its use as a generator for aerosol inhalation, powder particles are used as an alternative for inhalation therapy. The pulmonary deposition and clearance of inhaled powder particles was studied by positron emission tomography (PET) in ten patients with chronic obstructive pulmonary disease (COPD) and in five normal controls. The powder, 5 {mu}m in mean diameter, was water soluble and labelled with 2-deoxy-2[{sup 18}F]-fluoro-D-glucose ({sup 18}FDG). Powder inhalation was done with single deep inspiration from residual volume to total lung capacity. The initial deposition ratio in the right or left lung field to total inhaled dose, measured by an anteroposterior rectilinear scan, did not differ between normal and COPD patients. Ratios of radioactivity detected within the central and peripheral regions (the central to peripheral ratio) measured by the PET scan was not significantly different between COPD patients (4.8{+-}2.6, mean{+-}SD) and normals (2.6{+-}0.8, mean{+-}SD). However, the regional powder deposition in peripheral lung fields measured by the PET scan was significantly more uneven in COPD patients than in normal patients. The clearance rate of {sup 18}FDG, defined as the retention ratio of {sup 18}FDG activity to the initially deposited {sup 18}FDG at 60 and 120 min after inhalation, in the trachea, large bronchi or peripheral lung fields measured by tomographic scan showed a wider variation in COPD patients than in normals. To conclude, inhaled powder tended to be deposited more centrally and was distributed more unevenly in the peripheral lung in chronic obstructive pulmonary disease patients than in normals. This could be a limitation of powder inhalation used for therapy in chronic obstructive pulmonary disease patients. (au) 26 refs.

  6. Synthesis of Nanocobalt Powders for an Anode Material of Lithium-Ion Batteries by Chemical Reduction and Carbon Coating

    Directory of Open Access Journals (Sweden)

    Seong-Hyeon Hong

    2014-01-01

    Full Text Available Nanosized Co powders were prepared by a chemical reduction method with and without CTAB (cetyltrimethylammonium bromide, C19H42BrN and carbon-coating heat treatment at 700°C for 1 h, and the electrochemical properties of the prepared nanosized Co powders were examined to evaluate their suitability as an anode material of Li-ion batteries. Nanosized amorphous Co-based powders could be synthesized by a chemical reduction method in which a reducing agent is added to a Co ion-dissolved aqueous solution. When the prepared nanosized Co-based powders were subjected to carbon-coating heat treatment at 700°C for 1 h, the amorphous phase was crystallized, and a Co single phase could be obtained. The Co-based powder prepared by chemical reduction with CTAB and carbon-coating heat treatment had a smaller first discharge capacity (about 557 mAh/g than the Co-based powder prepared by chemical reduction without CTAB and carbon-coating heat treatment (about 628 mAh/g. However, the former had a better cycling performance than the latter from the third cycle. The carbon-coated layers are believed to have led to quite good cycling performances of the prepared Co-based powders from the third cycle.

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

    Science.gov (United States)

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

    2010-11-01

    Dry Powder Inhalers have drawn great attention from pharmaceutical scientists in recent years in particular those consisting of low-dose micronized drug particles associated with larger carrier particles and called interactive mixtures. However, there is little understanding of the relation between bulk powder properties such as powder structure and its aerodynamic dispersion performance. The aim of this work was to develop a simple method to measure the air permeability of interactive mixtures used in Dry Powder Inhalers by using Blaine's apparatus--a compendial permeameter and to relate it to the aerodynamic behaviour. The study was done with fluticasone propionate and terbutaline sulphate as drug models that were blended with several lactoses having different particle size distribution thus containing different percentages of fine particle lactose. The quality of the blends was examined by analysing the drug content uniformity. Aerodynamic evaluation of fine particle fraction was obtained using a Twin Stage Impinger. A linear correlation between a bulk property--air permeability of packed powder bed--and the fine particle fraction of drug was observed for the tested drugs. The air permeability reflects the quantity of the free particle fraction in the interparticulate spaces of powder bed that leads to fine particle fraction during fluidization in air flow. A theoretical approach was developed in order to link the air permeability of powder bed and drag force acting on powders during aerosolization process. The permeability technique developed in this study provides a potential tool for screening Dry Powder Inhaler formulations at the development stage. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Cheese powder as an ingredient in emulsion sausages

    DEFF Research Database (Denmark)

    Chen, Xiang; Ruiz Carrascal, Jorge; Petersen, Mikael Agerlin

    2017-01-01

    modified their profile of volatile compounds. Blue cheese increased some ketones, alcohols, and esters, while brown cheese brought typical Maillard reaction compounds. Overall, addition of cheese powders to sausages enhanced the intensity of flavour traits. A mixture of hard and blue cheese powder showed...... the highest effect on boosting saltiness, while brown cheese powder showed the strongest umami and meat flavour boosting effect, and sausages with added blue cheese powder showed a more intense aftertaste. Hardness significantly increased due to the addition of blue cheese powder. Addition of cheese powder...

  9. Characterization of Ni ferrites powders prepared by plasma arc discharge process

    Science.gov (United States)

    Safari, A.; Gheisari, Kh.; Farbod, M.

    2017-01-01

    The aim of this work was to synthesize a single-phase spinel structure from a mixture of zinc, iron and nickel powders by plasma arc discharge method. A mixture of zinc, iron and nickel powders with the appropriate molar ratio was prepared and formed into a cylindrical shape. The synthesis process was performed in air, oxygen and argon atmospheres with the applied arc current of 400 A and pressure of 1 atm. After establishing an arc between the electrodes, the produced powders were collected and their structure and magnetic properties were examined by XRD and VSM, respectively. ZnO as an impurity was appeared in the as-produced powders owing to the high reactivity of zinc atoms, preventing the formation of Ni-Zn ferrite. A pure spinel structure with the highest saturation magnetization (43.8 emu/g) was observed as zinc powders removed completely from the initial mixture. Morphological evaluations using field emission scanning electron microscopy showed that the mean size of fabricated nanoparticles was in the range 100-200 nm and was dependent on the production conditions.

  10. Monte Carlo simulation of light reflection from cosmetic powder particles near the human skin surface

    Science.gov (United States)

    Okamoto, Takashi; Kumagawa, Tatsuya; Motoda, Masafumi; Igarashi, Takanori; Nakao, Keisuke

    2013-06-01

    The reflection and scattering properties of light incident on human skin covered with powder particles have been investigated. A three-layer skin structure with a pigmented area is modeled, and the propagation of light in the skin's layers and in a layer of particles near the skin's surface is simulated using the Monte Carlo method. Assuming that only single scattering of light occurs in the powder layer, the simulation results show that the reflection spectra of light from the skin change with the size of powder particles. The color difference between normal and discolored skin is found to decrease considerably when powder particles with a diameter of approximately 0.25 μm are present near the skin's surface. The effects of the medium surrounding the particles, and the influence of the distribution of particle size (polydispersity), are also examined. It is shown that a surrounding medium with a refractive index close to that of the skin substantially suppresses the extreme spectral changes caused by the powder particles covering the skin surface.

  11. Molecular Dynamics Simulations of a Powder Model of the Intrinsically Disordered Protein Tau.

    Science.gov (United States)

    Fichou, Yann; Heyden, Matthias; Zaccai, Giuseppe; Weik, Martin; Tobias, Douglas J

    2015-10-01

    The tau protein, whose aggregates are involved in Alzheimer's disease, is an intrinsically disordered protein (IDP) that regulates microtubule activity in neurons. An IDP lacks a single, well-defined structure and, rather, constantly exchanges among multiple conformations. In order to study IDP dynamics, the combination of experimental techniques, such as neutron scattering, and computational techniques, such as molecular dynamics (MD) simulations, is a powerful approach. Amorphous hydrated powder samples have been very useful for studying protein internal dynamics experimentally, e.g., using neutron scattering. Thus, there is demand for realistic in silico models of hydrated protein powders. Here we present an MD simulation analysis of a powder hydrated at 0.4 g water/g protein of the IDP tau in the temperature range 20-300 K. By comparing with neutron scattering data, we identify the protein-water interface as the predominant feature determining IDP dynamics. The so-called protein dynamical transition is shown to be attenuated, but not suppressed, in the parts of the protein that are not exposed to the solvent. In addition, we find similarities in the mean-squared displacements of the core of a globular protein and "dry" clusters formed by the IDP in hydrated powders. Thus, the ps to ns dynamics of proteins in hydrated powders originate mainly from those residues in contact with solvent. We propose that by measuring the dynamics of protein assemblies, such as aggregates, one might assess qualitatively their state of hydration.

  12. PLGA Ethionamide Nanoparticles for Pulmonary Delivery: Development and in vivo evaluation of dry powder inhaler.

    Science.gov (United States)

    Debnath, Sujit Kumar; Saisivam, Srinivasan; Omri, Abdelwahab

    2017-10-25

    PLGA (50:50) nanoparticles were prepared to sustain the release of Ethionamide in order to decrease the dose and dosing frequency. It further modified in the form of dry powder inhaler to make suitable for pulmonary administration and increase drug residency in lungs. Ethionamide loaded PLGA nanoparticles were prepared by solvent evaporation method. Freeze dried nanoparticles and anhydrous inhalable grade lactose were mixed manually using geometrical dilution process to modify the nanoparticles in the form of dry powder inhaler. Animal study was conducted to correlate between in-vivo and in-vitro. PLGA nanoparticles showed initial burst release followed by zero order release up to 95.17±3.59% in 24h. Aerodynamic particle size of optimized dry powder inhaler was found as 1.79μm. There was no significant aggregation of dry powder inhaler during 6 months of stability study. Area under the concentration-time curve from 0h to infinity (AUC0(-∞)) signifies the prolong residency of ETH in body compartment, revealed from animal study. PLGA 50:50 coated nanoparticles released Ethionamide for the period of 24h in simulated lungs fluid. Correlation between in-vitro dissolution and in-vivo study was established after performing animal study. Prepared dry powder inhaler maintained Ethionamide concentration above minimum inhibitory concentration for more than 12h after single dose administration. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Sintering activation of 316L powder using a liquid phase forming powder

    Directory of Open Access Journals (Sweden)

    Nattaya Tosangthum

    2010-03-01

    Full Text Available It was found that the addition of a liquid forming powder (up to 6 wt.% of a gas-atomized tin powder to 316L powdercould activate the sintering process. Sintering activation could be observed by an increase of the sintered density and selected mechanical properties. When optimized tin powder content was used, shorter sintering time and lower sintering temperaturecould produce sintered 316L+tin materials with excellent mechanical properties. Electron dispersive spectroscopy analyses across 316L-tin-316L grains indicated that Ni transportation during the sintering process was enhanced by the presence of liquid tin.

  14. Acemetacin cocrystal structures by powder X-ray diffraction

    Directory of Open Access Journals (Sweden)

    Geetha Bolla

    2017-05-01

    Full Text Available Cocrystals of acemetacin drug (ACM with nicotinamide (NAM, p-aminobenzoic acid (PABA, valerolactam (VLM and 2-pyridone (2HP were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R32(9R22(8R32(9 with three different syn amides (VLM, 2HP and caprolactam. The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I or syn (type II. ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O...H, N...H, Cl...H and C...H interactions. The physicochemical properties of these cocrystals are under study.

  15. Ultra-fine powders using glycine-nitrate combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Chick, L.A.; Pederson, L.R.; Bates, J.L.; Maupin, G.D.

    1991-05-01

    Fabrication of advanced, multifunctional materials frequently requires the synthesis of complex, ultra-fine powders comprised of a single phase containing several elements (multicomponent) or of several phases that are intimately mixed on a micro-scale (composite). A new combustion synthesis method, the glycine/nitrate process (GNP), is particularly useful for synthesizing ultra-fine, multicomponent oxide powders. Examples discussed include La(Sr)CrO{sub 3} and La(Sr)FeO{sub 3} perovskites and a composite of three phases, NiO, NiFe{sub 2}O{sub 4}, and Cu metal. The GNP consists of two basic steps. First, metal nitrates and a low molecular weight amino acid are dissolved in water. Second, the solution is boiled until it thickens. This viscous liquid ignites and undergoes self-sustaining combustion, producing an ash composed of the oxide product. Most refractory oxides that are composed of a combination of metals having stable nitrates should be possible to synthesize using GNP. 15 refs., 8 figs.

  16. Powder-Metallurgy Process And Product

    Science.gov (United States)

    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.

  17. Laboratory Powder Metallurgy Makes Tough Aluminum Sheet

    Science.gov (United States)

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

    1993-01-01

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

  18. Progress in Titanium Metal Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Randall M. German

    2013-08-01

    Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  19. Progress in Titanium Metal Powder Injection Molding.

    Science.gov (United States)

    German, Randall M

    2013-08-20

    Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM) that must be simultaneously satisfied-density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  20. Neutron Powder Diffraction and Constrained Refinement

    DEFF Research Database (Denmark)

    Pawley, G. S.; Mackenzie, Gordon A.; Dietrich, O. W.

    1977-01-01

    The first use of a new program, EDINP, is reported. This program allows the constrained refinement of molecules in a crystal structure with neutron diffraction powder data. The structures of p-C6F4Br2 and p-C6F4I2 are determined by packing considerations and then refined with EDINP. Refinement...

  1. High-Performance Polyimide Powder Coatings

    Science.gov (United States)

    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.

  2. Tomato pomace powder ameliorated cisplatin-induced ...

    African Journals Online (AJOL)

    Tomato (Lycopersicon esculentum) pomace powder (TPP) may be a preventive agent by virtue of its known antioxidant property. The possible protective role of TPP against cisplatin-induced alteration of the microanatomy of rat brain was investigated. Thirty rats were divided equally into five groups: control, propylene glycol ...

  3. Balanced mechanical resonator for powder handling device

    Science.gov (United States)

    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.

  4. Quantification of the compactibility of pharmaceutical powders

    DEFF Research Database (Denmark)

    Sonnergaard, Jørn

    2006-01-01

    The purpose of this study is to investigate and to quantify the compactibility of pharmaceutical powders by a simple linear relationship between the diametral compressive strength of tablets and the applied compaction pressure. The mechanical strength of the tablets is characterized as the crushing...

  5. Sinterable Powders from Laser Driven Reactions

    Science.gov (United States)

    1979-07-01

    Agency or the U. S. Government. unclassified - S7 CURITY CLASIFPICATION of THI PAGE ,(1in Dato at" ’he laser heated process has been modeled in terms...for Si, Si 3N4 , and SiC are presented below. A comprehensive tabular listing of the individual run conditions and the resultant powder characteristics

  6. 21 CFR 73.1647 - Copper powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Copper powder. 73.1647 Section 73.1647 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR... use in color additive mixtures for coloring externally applied drugs. (b) Specifications. Copper...

  7. Powder Characterization and Optimization for Additive Manufacturing

    NARCIS (Netherlands)

    Cordova, Laura; Campos, Mónica; Tinga, Tiedo

    2017-01-01

    Achieving the optimal quality for Additive Manufactured (AM) parts does not only depend on setting the right process parameters. Material feedstock also plays an important role when aiming for high performance products. The metal AM processes that are most applicable to industry, Powder Bed Fusion

  8. Effectiveness of botanical powders against Callosobruchus maculatus

    African Journals Online (AJOL)

    Oluchi

    2013-03-20

    Mar 20, 2013 ... The phytochemical analysis revealed that alkaloids, steroids, glycosides and terpenoids were present in .... Phytochemistry of plant materials. The 5 g of each powdered plant material was weighed using ..... Bruchidae) on stored cowpea. Unpublished M.Sc. Thesis, Ahmadu. Bello University, Zaria, Nigeria ...

  9. Synergy Between Moringa oleifera Seed Powder

    African Journals Online (AJOL)

    Administrator

    with alum for water purification in rural communities. Keywords: Phytochemicals, coagulant ... derivatives are widely used in water treatment (Najm et al.,1998). However, there is a fear that aluminum may induce ..... well as the cost of water treatment (Muyibi & Okuofu, 1995). Blending alum and M. oleifera seed powder in ...

  10. (11) EFFECT OF POWDERED CASTOR BEAN

    African Journals Online (AJOL)

    Adeyinka Odunsi

    Ladoke Akintola University of Technology Ogbomoso, to determine the effects of powdered castor oil seed. (Ricinus communis L.Euphorbiaceae) on kidney, liver, spleen of albino rats. The rats were in five groups, which were replicated three (3) times. The castor oil seed was turned to powdery form using pestle and mortal.

  11. Evaluation of powder metallurgy superalloy disk materials

    Science.gov (United States)

    Evans, D. J.

    1975-01-01

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

  12. FLY ASH: AN ALTERNATIVE TO POWDERED ACTIVATED ...

    African Journals Online (AJOL)

    Preferred Customer

    This paper reports the use of powdered activated carbon (PAC) and raw coal fly ash (RFA) in the removal of eosin dye from aqueous ... calculation is hereby reported to know the amount of adsorbent required for efficient removal of eosin dye. EXPERIMENTAL. Dye properties and preparation. Analytical grade eosin dye ...

  13. Evaluating the Johanson theory for titanium powder

    CSIR Research Space (South Africa)

    Chikosha, S

    2015-05-01

    Full Text Available Direct powder rolling (DPR)/roll compaction has been labelled a complex and sample sensitive process. As such the design of the instrument and the determination of the optimal processing conditions for a given feed are very challenging...

  14. COMPARATIVE EFFICACY OF Acorus calamus POWDER AND ...

    African Journals Online (AJOL)

    The efficacy of the powder of a natural plant product (Acorus calamus L.) and two synthetic insecticides (i.e. Pirimiphos methyl and Rotenone) was compared in the laboratory for the control Sitophilus oryzea (L), Rhizopertha dominica (F) and Tribolium castaneum (Herbst) in stored wheat grains. Seven concentrations of the ...

  15. [Analysis on the chemical compositions of the volatile oil from ultramicro-powder and common grinding powder of Cinnamomum cassia].

    Science.gov (United States)

    Liu, Li; Liu, Nu-Yun; Liu, Qiang

    2008-03-01

    To analyse and compare the chemical compositions in the volatile oil from Utramicro-powder and Common Grinding Powder of Cinnamomum. The volatile oil was extracted by steam-stilling and analyzed by GC-MS. The relative content of each component was calculated by area normalization method. 34 and 19 peaks were isolated from Ultramicro-powder and Common Grinding Powder of Cinnamomum respectively. All of them were identified. The chemical components of the volatile oil from Ultramicro-powder and Common Grinding Powder of Cinnamomum are reported, the results here provides scientific proof for the application in external preparation of Cinnamomum.

  16. Particle-based simulations of powder coating in additive manufacturing suggest increase in powder bed roughness with coating speed

    Directory of Open Access Journals (Sweden)

    Parteli Eric J. R.

    2017-01-01

    Full Text Available We have developed the first particle-based numerical tool to simulate the coating of powder particles in additive manufacturing devices. Our Discrete Element Method considers realistic particle shapes and incorporates attractive interaction (van-der-Waals forces between the particles. From simulations of powder coating using a roller as coating device, we find that the surface roughness of the powder bed scales with the square of coating speed. Moreover, we find that using fine, highly polydisperse powders may lead to larger powder bed roughness, compared to process simulations using coarser powders, due to the formation of agglomerates resulting from cohesive forces.

  17. Coating powdered copper catalyst with yttria sol

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kuan-Ying [Department of Chemical and Engineering and Materials Science, Yuan Ze University, Chung-Li, Taiwan (China); Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Shen, Chia-Chieh, E-mail: ccshen@saturn.yzu.edu.tw [Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Department of Mechanical Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Graduate School of Renewable Energy Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Lee, Chi-Yuan; Lee, Shuo-Jen [Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Department of Mechanical Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Graduate School of Renewable Energy Engineering, Yuan Ze University, Chung-Li, Taiwan (China); Leu, Chih-Hsing [Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan (China); Wang, Jung-Hui [Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China); Yeh, Chuin-Tih [Department of Chemical and Engineering and Materials Science, Yuan Ze University, Chung-Li, Taiwan (China); Fuel Cell Center, Yuan Ze University, Chung-Li, Taiwan (China)

    2011-07-15

    Research highlights: {yields} The neutral Y{sub 2}O{sub 3} sol is an effective binder for coating powders of CuZnAl catalyst. {yields} A particle size ratio of 15 for catalyst to binder is suggested for stable coating. {yields} Sufficient stirring is an important step in the catalyst slurry preparation. - Abstract: A commercial Y{sub 2}O{sub 3} sol was tested as a binder for coating CuZnAl catalyst powder onto microchannels of a stainless steel plate (SSP). Coated plates were used to fabricate microchannel reactors that generate hydrogen via the steam reforming of methanol (SRM). Washcoating slurries were prepared by suspending catalyst powders into the sol. Slurry parameters, such as solid content, binder content, pH value, and stir time, were optimized to achieve a stable catalyst coating and good SRM performance. The expected stable coating could be obtained from neutral (pH 7) Y{sub 2}O{sub 3} slurry that is required for a negligible dissolution of the copper component of the catalyst. The experimental coating stability generally improved with the slurry stir time. Observed improvements were attributed to a dispersion of catalyst powders in the slurry through a two-step mechanism: the mechanical disassembly of agglomerated CuZnAl powders into primary particles, and the repelling of dissembled particles through adsorption of positively charged Y{sub 2}O{sub 3} binders. A reasonable reaction temperature of 280 deg. C was found for 95% conversion of methanol in SRM from the resulted microchannel reactors. A low CO fraction of 0.3% was also found in the hydrogen-rich gas reformed.

  18. Moisture-induced caking of beverage powders.

    Science.gov (United States)

    Chávez Montes, Edgar; Santamaría, Nadia Ardila; Gumy, Jean-Claude; Marchal, Philippe

    2011-11-01

    Beverage powders can exhibit caking during storage due to high temperature and moisture conditions, leading to consumer dissatisfaction. Caking problems can be aggravated by the presence of sensitive ingredients. The caking behaviour of cocoa beverage powders, with varying amounts of a carbohydrate sensitive ingredient, as affected by climate conditions was studied in this work. Sorption isotherms of beverage powders were determined at water activities (a(w) ) ranging from 0.1 to 0.6 in a moisture sorption analyser by gravimetry and fitted to the Brunauer-Emmett-Teller (BET) or the Guggenheim-Anderson-de Boer (GAB) equation. Glass transition temperatures (T(g) ) at several a(w) were analysed by differential scanning calorimetry and fitted to the Gordon-Taylor equation. Deduced T(g) = f(a(w) ) functions helped to identify stability or caking zones. Specific experimental methods, based on the analysis of mechanical properties of powder cakes formed under compression, were used to quantify the degree of caking. Pantry tests complemented this study to put in evidence the visual perception of powder caking with increasing a(w) . The glass transition approach was useful to predict the risks of caking but was limited to products where T(g) can be measured. On the other hand, quantification of the caking degree by analysis of mechanical properties allowed estimation of the extent of degradation for each product. This work demonstrated that increasing amounts of a carbohydrate sensitive ingredient in cocoa beverages negatively affected their storage stability. Copyright © 2011 Society of Chemical Industry.

  19. Oxidation behaviour of boron carbide powder

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.Q. [College of Materials Science and Engineering, Nanjing University of Technology, New Model Road 5, Nanjing, Jiangsu 210009 (China)]. E-mail: Li.Yuanqiang@nims.go.jp; Qiu, T. [College of Materials Science and Engineering, Nanjing University of Technology, New Model Road 5, Nanjing, Jiangsu 210009 (China)

    2007-01-25

    Isothermal oxidation behaviour of powdered boron carbide (B{sub 4}C) with the fine (1.52 {mu}m), medium (22.5 {mu}m) and coarse (59.6 {mu}m) particle size has been studied in air ranging from 500 to 800 deg. C. The oxidation rate strongly depends on the particle size of boron carbide and temperature. The smaller particle size the higher oxidation rate of B{sub 4}C powder due to its larger surface area. When B{sub 4}C powder is oxidized in air, a B{sub 2}O{sub 3} glass film is formed on the surface of B{sub 4}C grain which retards the further oxidation reaction. The oxidation kinetics is approximately fitted to the diffusion-controlled rate law which can be described by the Jander's equation. The apparent activation energy for the fine-, medium- and coarse-B{sub 4}C powders is 209.4 {+-} 11.4, 212.7 {+-} 35.8 and 219.2 {+-} 45.3 kJ mol{sup -1}, respectively, slightly varying with the impurity content of B{sub 4}C powders. The type of rate law suggests that the diffusion of oxygen through the oxide layer is the rate-limiting step in the oxidation reactions. In addition, the change in the oxidation process at higher oxidation fraction might associate with the B{sub 2}O{sub 3} volatilization at higher temperatures.

  20. Powder metallurgy of turbine disc alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ingesten, N.G. (Dep. of Engineering Metals)

    1981-03-01

    The first part embraced a study of carbide precipitated in IN 100 and astrology powders. The powder was heat treated at temperatures between 950/sup 0/C and 1150/sup 0/C. After aging at 950-1100/sup 0/C the MC-carbides formed during atomization were replaced by M/sub 23/C/sub 6/-carbides. After 1150/sup 0/C treatments the MC carbides were present again. Precipitation comparable with that obtained in HIP:ed specimens was not observed at free particle surfaces. However, powder particles which had agglomerated during atomization often exhibited considerable precipitation at contiguous surfaces. Obviously, contact between the particles must occur if coarse precipitation at particle surfaces is to develop. Reduced PPB-precipitation was obtained by pre-heat- treatment of powder before compaction. It is suggested that the carbon otherwise available for PPB-precipitation forms carbides in the interior of the powder particles. The aim of the second part was to ..gamma..-strengthen a Co-based super-alloy (Co-15Cr-3Mo-5Ti). Here the Ti-addition gives a coherent and ordered ..gamma..-phase Co/sub 3/Ti. However, upon ageing the alloy is unstable in order to increase the stability modifications of the alloy were prepared by: leaving out the Mo-content, adding 10 % Ni and by decreasing the Ti-content to 4.2 %. In addition, the effect of enhanced grain size and of deformation was investigated. Significant reduction of the transformation rate was only obtained by decresing the Ti-content while deformation of the alloy greatly increased the transformation rate.(author).

  1. Effect of Powder Morphologies on the Property of Conductive Silicone Rubber Filled with Carbonyl Nickel Powder

    Science.gov (United States)

    Xiao, Weimin; Lei, Yongping; Xia, Zhidong; Chen, Xin; Han, Yu; Nie, Jingkai; Huang, Pei

    2017-11-01

    Conductive silicone rubbers filled with the spherical, flaky, and chain-spherical carbonyl nickel powder were prepared. The effects of powder morphologies on their electromagnetic and mechanical properties were analyzed. The electromagnetic shielding effectiveness (SE) and tensile strength of the rubbers varies with their powder morphologies: the SE values increase from the spherical and the chain-spherical to the flaky morphology in the frequency range of 100-400 MHz. In the range of 500-1500 MHz, the SE rises from the spherical and the flaky to the chain-spherical morphologies. In addition, the tensile strength increases from the spherical and the flaky to the chain-spherical morphologies. These variations are related to the differences in the conductive network structure and the powder distribution in the rubber.

  2. Effects of dietary supplement of turmeric powder (Curcuma longa ...

    African Journals Online (AJOL)

    Ross 308) to investigate the effects of dietary supplementation with various levels of turmeric powder on blood constituents and antioxidant activity. The chicks were randomly assigned to eight dietary groups, which were given turmeric powder ...

  3. Research on Durability of Recycled Ceramic Powder Concrete

    Science.gov (United States)

    Chen, M. C.; Fang, W.; Xu, K. C.; Xie, L.

    2017-06-01

    Ceramic was ground into powder with 325 mesh and used to prepare for concrete. Basic mechanical properties, carbonation and chloride ion penetration of the concrete tests were conducted. In addition, 6-hour electric fluxes of recycled ceramic powder concrete were measured under loading. The results showed that the age strength of ceramics powder concrete is higher than that of the ordinary concrete and the fly ash concrete. The ceramic powder used as admixture would reduce the strength of concrete under no consideration of its impact factor; under consideration of the impact factor for ceramic powder as admixture, the carbonation resistance of ceramic powder concrete was significantly improved, and the 28 day carbonation depth of the ceramic powder concrete was only 31.5% of ordinary concrete. The anti-chloride-permeability of recycled ceramic powder concrete was excellent.

  4. Physical properties of yoghurt powder produced by spray drying

    National Research Council Canada - National Science Library

    Koç, Banu; Sakin-Yılmazer, Melike; Kaymak-Ertekin, Figen; Balkır, Pınar

    2014-01-01

    ... (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...

  5. Influence of Ultrafine 2CaO·SiO2 Powder on Hydration Properties of Reactive Powder Concrete

    Directory of Open Access Journals (Sweden)

    Hongfang Sun

    2015-09-01

    Full Text Available In this research, we assessed the influence of an ultrafine 2CaO·SiO2 powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (SEM, mineralogical composition were determined by X-ray diffraction, while the heat release characteristics up to the age of 3 days were investigated by calorimetry. Moreover, the properties of cementitious system in fresh and hardened state (setting time, drying shrinkage, and compressive strength with 5% ordinary Portland cement replaced by ultrafine powder were evaluated. From SEM micrographs, the particle size of ultrafine powder was found to be up to several hundred nanometers. The hydration product started formulating at the age of 3 days due to slow reacting nature of belitic 2CaO·SiO2. The initial and final setting times were prolonged and no significant difference in drying shrinkage was observed when 5% ordinary Portland cement was replaced by ultrafine powder. Moreover, in comparison to control reactive powder concrete, the reactive powder concrete containing ultrafine powder showed improvement in compressive strength at and above 7 days of testing. Based on above, it can be concluded that the manufactured ultrafine 2CaO·SiO2 powder has the potential to improve the performance of a reactive powder cementitious system.

  6. X-ray characterization by energy-resolved powder diffraction

    Directory of Open Access Journals (Sweden)

    G. Cheung

    2016-08-01

    Full Text Available A method for single-shot, nondestructive characterization of broadband x-ray beams, based on energy-resolved powder diffraction, is described. Monte-Carlo simulations are used to simulate data for x-ray beams in the keV range with parameters similar to those generated by betatron oscillations in a laser-driven plasma accelerator. The retrieved x-ray spectra are found to be in excellent agreement with those of the input beams for realistic numbers of incident photons. It is demonstrated that the angular divergence of the x rays can be deduced from the deviation of the detected photons from the Debye-Scherrer rings which would be produced by a parallel beam. It is shown that the angular divergence can be measured as a function of the photon energy, yielding the angularly resolved spectrum of the input x-ray beam.

  7. A Novel Technique for the Synthesis of Nanodiamond Powder

    Directory of Open Access Journals (Sweden)

    Leiming Fang

    2013-01-01

    Full Text Available We developed a novel technique to synthesize nanodiamond powder through the decomposition of graphitic C3N4 under high pressure and high temperature. The nanodiamond obtained by the present method is in an extremely pure form with no sp2 carbon contaminations. Individual nanodiamond grains are very uniform in size and virtually monodispersed single crystals. The grain size can be controlled from less than 1 nm to several hundred nanometers by adjusting the heating temperature (and also potentially by controlling pressure used for the synthesis. The present product requires neither post-surface treatment to remove outer shell made of sp2 carbons nor deglomeration and size classification unlike the case for nanodiamond obtained by the conventional TNT detonation method.

  8. Study of Velocity and Materials on Tribocharging of Polymer Powders for Powder Coating Applications

    Science.gov (United States)

    Biris, Alex S.; Trigwell, Steve; Sims, Robert A.; Mazumder, Malay K.

    2005-01-01

    Electrostatic powder deposition is widely used in a plethora of industrial-applications ranging from the pharmaceutical and food.industries, to farm equipment and automotive applications. The disadvantages of this technique are possible back corona (pin-like formations) onset and the Faraday penetration limitation (when the powder does not penetrate in some recessed areas). A possible solution to overcome these problems is to use tribochargers to electrostatically charge the powder. Tribocharging, or contact charging while two materials are in contact, is related to the work function difference between the contacting materials and generates bipolarly charged particles. The generation of an ion-free powder cloud by tribocharging with high bipolar charge and an overall charge density of almost zero, provides a better coverage of the recessed areas. In this study, acrylic and epoxy powders were fluidized and charged by passing through stainless steel, copper, aluminum, and polycarbonate static mixers, respectively. The particle velocity was varied to determine its effect on the net charge-to-mass ratio (QIM) acquired by the powders. In general, the Q/M increases rapidly when the velocity was increased from 1.5 to 2.5 m/s, remaining almost constant for higher velocities. Charge separation experiments showed bipolar charging for all chargers.

  9. Dust generation in powders: Effect of particle size distribution

    OpenAIRE

    Chakravarty Somik; Le Bihan Olivier; Fischer Marc; Morgeneyer Martin

    2017-01-01

    This study explores the relationship between the bulk and grain-scale properties of powders and dust generation. A vortex shaker dustiness tester was used to evaluate 8 calcium carbonate test powders with median particle sizes ranging from 2μm to 136μm. Respirable aerosols released from the powder samples were characterised by their particle number and mass concentrations. All the powder samples were found to release respirable fractions of dust particles which end up decreasing with time. Th...

  10. 49 CFR 173.170 - Black powder for small arms.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Black powder for small arms. 173.170 Section 173... Class 7 § 173.170 Black powder for small arms. Black powder for small arms that has been classed in... § 173.56; (d) Each completed package must be marked “BLACK POWDER FOR SMALL ARMS” and “NA 0027”; and (e...

  11. Optimization of the composition of the powdered cereal sprouts mixtures

    Directory of Open Access Journals (Sweden)

    Tumbas-Šaponjac Vesna T.

    2016-01-01

    Full Text Available Sprouts of cereals have received significant attention as functional food due to their nutritional and functional value. Consumption of sprouts has become increasingly popular among people interested in improving and maintaining their health status by changing dietary habits. Cereal grains contain several classes of phytochemicals, i.e. phenolics, chlorophylls, and carotenoids. However, their nutritional and chemical profile is altered and improved during germination. The purpose of this study was to find the best ratio of the powdered wheat (WS, oat (OS and barley (BS sprouts for designing the cereal sprout mixture (CSM with the highest total phenolic content (TPh and antioxidant capacity (AC, using Simplex-Centroid experimental design and response surface methodology (RSM. Single- and multi-response optimizations showed that OS did not contribute to TPh or AC values of CSM and, therefore, was not included in any of the compositions of the optimized CSM. Single-response optimizations showed that the highest TPh was found for CSM containing 82% BS and 18% WS, while the best AC was found for pure BS. The predicted ratio of cereal sprout powders in CSM obtained by multi-response optimization was: 96% BS and 4% WS. This mixture possessed the highest predicted TPh and AC (372.32 mg GAE/100 g, 549.99 μmol TE/100 g, respectively, which was confirmed to be in accordance with the experimental values. Based on the results obtained in this study, a designed CSM is proposed as a convenient ingredient of functional food products, dietary supplements and nutraceuticals.

  12. 49 CFR 173.171 - Smokeless powder for small arms.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Smokeless powder for small arms. 173.171 Section 173.171 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS... Class 7 § 173.171 Smokeless powder for small arms. Smokeless powder for small arms which has been...

  13. Magnetic properties of lanthanum orthoferrite fine powders prepared ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Fine powders of lanthanum iron oxide, LaFeO3, have been prepared by solid state reaction as well as sol–gel synthesis and nebulized spray pyrolysis. Struc- tures, morphologies and magnetic susceptibility measurements of these powders have been examined. The powders prepared by all the three ...

  14. Plant dried powders as biocatalysts: Hydrolysis of 1- phenylpropanol ...

    African Journals Online (AJOL)

    The hydrolytic ability of plant dried powders, lyophilized or acetone dried, was tested on the hydrolysis of racemic 1-phenylpropanol acetate. Most of the twenty powders tested showed hydrolytic activity, however the best values of conversion and enantioselectivity were reached with the lyophilized powder of nopal (27% ...

  15. Changes in hydroxyapatite powder properties via heat treatment

    Indian Academy of Sciences (India)

    The properties of hydroxyaptite (HA) powder, especially its physical one, are largely influenced by the heat treatment process. Controlling of these changes is vital in deciding the suitability of applying this powder in wet processing routes for green body fabrication. Chemically, the crystallinity of the HA powder was found to ...

  16. METHOD OF PRODUCING SHAPED BODIES FROM POWDERED METALS

    Science.gov (United States)

    Blainey, A.

    1960-05-31

    A method is given for enclosing a body of uranium in a sheath of compacted beryllium or zirconium powder and comprises enveloping the body with uncompacted powder and pressing at a temperature above the beta - gamma transition point of uranium, thereby causing the uranium to flow and isotropically compress the powder.

  17. 21 CFR 520.540a - Dexamethasone powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dexamethasone powder. 520.540a Section 520.540a... DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.540a Dexamethasone powder. (a) Specifications. Dexamethasone powder is packaged in packets containing 10 milligrams of dexamethasone. (b...

  18. Powder metallurgical processing and metal purity: A case for ...

    Indian Academy of Sciences (India)

    Unknown

    powder metallurgy route, because of many associated advantages (Upadhyaya 1997). The purity of the starting metal or ceramic powder is of significance in controlling the microstructure/properties/processing and performance of such products. The major methods of production of metal powders are: chemical, physical and ...

  19. 21 CFR 520.1720e - Phenylbutazone powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Phenylbutazone powder. 520.1720e Section 520.1720e... DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.1720e Phenylbutazone powder. (a) Specifications—(1) Each 1.15 grams (g) of powder contains 1 g phenylbutazone. (2) Each 10 g of...

  20. Determination of Dispersion of Zucchini and Cabbage Powders

    Directory of Open Access Journals (Sweden)

    M.I. Pogozhyh

    2013-07-01

    Full Text Available Particle size of cabbage and zucchini powders was determined by microscopy. It is shown that under the identical conditions of drying, grinding and other stages of the process, the cabbage powder has a higher content of fine fraction. Promising application of cabbage and zucchini powders in restaurant industry is indicated. Case diagram of the received production use is developed.

  1. 21 CFR 520.2087 - Roxarsone soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Roxarsone soluble powder. 520.2087 Section 520...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.2087 Roxarsone soluble powder. (a) Specifications. Each ounce (avoirdupois) of soluble powder contains 21.7 grams of roxarsone...

  2. 21 CFR 520.44 - Acetazolamide sodium soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acetazolamide sodium soluble powder. 520.44 Section 520.44 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Acetazolamide sodium soluble powder. (a) Specifications. The drug is in a powder form containing acetazolamide...

  3. 21 CFR 520.110 - Apramycin sulfate soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Apramycin sulfate soluble powder. 520.110 Section 520.110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... sulfate soluble powder. (a) Specifications. A water soluble powder used to make a medicated drinking water...

  4. 21 CFR 520.1044c - Gentamicin sulfate soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentamicin sulfate soluble powder. 520.1044c Section 520.1044c Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Gentamicin sulfate soluble powder. (a) Specifications. Each gram of gentamicin sulfate soluble powder...

  5. Controlling the composition and the magnetic properties of hexagonal Co2Z ferrite powders synthesized using two different methods

    Science.gov (United States)

    Rashad, M. M.; Rasly, M.; El-Sayed, H. M.; Sattar, A. A.; Ibrahim, I. A.

    2013-09-01

    Polycrystalline Co2Z hexaferrite (Ba3Co2Fe24O41) powders have been prepared via two wet chemical routes: sol gel auto-combustion (SGA) and co-precipitation (CP) methods. The effects of synthesis conditions on the crystal structure, crystallite size, morphology, and magnetic properties were systematically studied. The results revealed that single Co2Z hexaferrite phase was obtained at relatively low temperature 1250 ∘C for 5 h via the SGA method whereas it was formed at 1300 ∘C for 6 h using the CP pathway. The microstructures of the pure powders appeared as a hexagonal platelet-like structure. The particle size of the pure Co2Z powders by CP method was higher than as obtained by the SGA method. The soft characteristic loops were obtained for single Co2Z hexaferrite phase synthesized using both routes. High saturation magnetization ( M s =53.7 emu/g) was achieved for the Co2Z powder synthesized via the CP method compared with the formed single phase synthesized via the SGA method ( M s =47.0 emu/g). Good dielectric and dynamic magnetic properties were obtained for the Co2Z powder synthesized via the SGA method in comparison with the sample synthesized via CP method. The results obtained are discussed on the basis of electromagnetic theory.

  6. Oxidation behavior of Ni powder and Ni powder compact; Ni fun oyobi Ni fun atsufuntai no sanka kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, M.; Ochiai, S.; Watanabe, Y. [Teikyo Univ., Tokyo (Japan)

    1997-09-15

    With an objective to investigate reactions of metal powder and metal powder compact having open pores with gases, their oxidation behavior was elucidated by taking Ni powder and Ni powder compact as examples. Oxidation rate of the Ni powder can be expressed by the Jander equation, and activation energy for the oxidation was 0.948 times 10 {sup 5} J/mol. Oxidation rate of the Ni powder compact is equal to that of powder not made into compact in the initial stage of the oxidation, but it decreases as time elapses because of occurrence of packing of oxide. Difference in oxidation rate inside and outside the powder compact is very little. The oxidation rate of the powder compact was analyzed by using an improved Jander model. More specifically, a model was used, in which concentration difference of diffused components in the oxides decreases with progress of the oxidation, whereas 1.113 times 10 {sup 5} J/mol was derived as the activation energy of the oxidation. The cause for the activation energy for the oxidation of the powder and powder compact being about half of that for bulk Ni is because of low temperature oxidation of the powder, and tensile stress generated between metal particles and spherical shell shaped oxides, which make production of Ni {sup 2+} more difficult. 5 refs., 4 figs., 1 tab.

  7. Fabricating solid carbon porous electrodes from powders

    Science.gov (United States)

    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 (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.

  8. Powder metallurgy bearings for advanced rocket engines

    Science.gov (United States)

    Fleck, J. N.; Killman, B. J.; Munson, H.E.

    1985-01-01

    Traditional ingot metallurgy was pushed to the limit for many demanding applications including antifriction bearings. New systems require corrosion resistance, better fatigue resistance, and higher toughness. With conventional processing, increasing the alloying level to achieve corrosion resistance results in a decrease in other properties such as toughness. Advanced powder metallurgy affords a viable solution to this problem. During powder manufacture, the individual particle solidifies very rapidly; as a consequence, the primary carbides are very small and uniformly distributed. When properly consolidated, this uniform structure is preserved while generating a fully dense product. Element tests including rolling contact fatigue, hot hardness, wear, fracture toughness, and corrosion resistance are underway on eleven candidate P/M bearing alloys and results are compared with those for wrought 440C steel, the current SSME bearing material. Several materials which offer the promise of a significant improvement in performance were identified.

  9. Adsorption Studies of Radish Leaf Powder

    Directory of Open Access Journals (Sweden)

    Ankita

    2016-01-01

    Full Text Available Radish leaves (Raphanus sativus powder fractions was subjected to moisture adsorption isotherms at different isothermal temperature conditions from 15-45°C with an equal interval of 10°C. The sorption data obtained in gravimetric static method under 0.11–0.90 water activity conditions were subjected for sorption isotherms and found to be typical sigmoid trend. Experimental data were assessed for the applicability in the prediction through sorption models fitting and found that Polynomial and GAB equations performed well over all fitted models in describing equilibrium moisture content – equilibrium relative humidity (EMC–ERH relationships for shelf stable dehydrated radish leaf powder, over the entire range of temperatures condition under study. The net isosteric heat of sorption, differential entropy and free energy were determined at different temperatures and their dependence was seen with respect to equilibrium moisture content.

  10. Dry powder mixes comprising phase change materials

    Science.gov (United States)

    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 be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and in cementitious compositions of the type in which it is beneficial to use a pcm material. The silica-pcm mix can also be admixed with soil to provide a soil warming effect and placed about a tree, flower, or shrub.

  11. Ignition of THKP and TKP pyrotechnic powders :

    Energy Technology Data Exchange (ETDEWEB)

    Maharrey, Sean P.; Erikson, William W; Highley, Aaron M.; Wiese-Smith, Deneille; Kay, Jeffrey J

    2014-03-01

    We have conducted Simultaneous Thermogravimetric Modulated Beam Mass Spectrometry (STMBMS) experiments on igniter/actuator pyrotechnic powders to characterize the reactive processes controlling the ignition and combustion behavior of these materials. The experiments showed a complex, interactive reaction manifold involving over ten reaction pathways. A reduced dimensionality reaction manifold was developed from the detailed 10-step manifold and is being incorporated into existing predictive modeling codes to simulate the performance of pyrotechnic powders for NW component development. The results from development of the detailed reaction manifold and reduced manifold are presented. The reduced reaction manifold has been successfully used by SNL/NM modelers to predict thermal ignition events in small-scale testing, validating our approach and improving the capability of predictive models.

  12. Properties of Waste Tire Rubber Powder

    Directory of Open Access Journals (Sweden)

    M. Bekhiti

    2014-08-01

    Full Text Available Scrap tires are abundant and alarming waste. The aggregates resulting from the crushing of the waste tires are more and more used in the field of civil engineering (geotechnical, hydraulic works, light concretes, asphaltic concretes, etc.. Depending on the type of the used tires, dimensions and possible separations and treatment, the physical and mechanical characteristics of these aggregates might change. Some physical, chemical and direct shear tests were performed on three gradation classes of waste tire rubber powder. The tests results were combined with data from previous studies to generate empirical relationships between cohesion, friction angle and particle size of waste tire powder rubber. A cubic (third order regression model seems to be more appropriate compared to linear and quadratic models.

  13. Solving Crystal Structures from Powder Diffraction Data

    DEFF Research Database (Denmark)

    Christensen, A. Nørlund; Lehmann, M. S.; Nielsen, Mogens

    1985-01-01

    High resolution powder data from both neutron and X-ray (synchrotron) sources have been used to estimate the possibility of direct structure determination from powder data. Two known structures were resolved by direct methods with neutron and X-ray data. With synchrotron X-ray data, the measured...... range of data was insufficient for a structure analysis, but the R-factor calculations showed the intensities extracted from the profile data to be of acceptable quality. The results were used to estimate the largest structure that might be solved using routine techniques. It was found that the limit...... would be near twenty atoms in the asymmetric part of a centro-symmetric structure....

  14. Physical and chemical stability of tagatose powder.

    Science.gov (United States)

    Grant, Lenese D; Bell, Leonard N

    2012-03-01

    Tagatose is a reduced-calorie monosaccharide that displays prebiotic properties. Water can interact with powdered tagatose to varying extents, depending upon the storage environment. Adsorbed water can impact the stability of tagatose, altering its functionality and usability as an ingredient. The objective of this study was to evaluate the physical and chemical stability of bulk tagatose powder as a function of relative humidity (RH) and temperature. Powdered tagatose was stored in desiccators at 20, 30, and 40 °C and 33% to 85% RH. Moisture contents (MC), physical characteristics, tagatose degradation profiles, and browning kinetics were monitored for 12 mo. The critical RH associated with deliquescence (RH0) was approximately 85% at 20 °C. MC values below RH0 were all less than 2% (wb). The MC at 85% RH ranged from 55% to 80% (wb), increasing as temperature decreased. At 33% RH and 20 °C tagatose remained a free flowing powder. As either temperature or RH increased, varying degrees of physical caking occurred. At 85% RH, tagatose deliquesced at all temperatures. Browning occurred in all samples at 40 °C. Despite physical caking and browning, measurable tagatose degradation was only observed in the deliquesced sample at 85% RH and 40 °C, where 20% loss occurred in 6 mo. Although extreme RHs and temperatures are required for tagatose degradation to occur, intermediate RHs and temperatures promote physical caking and deliquescence, which create handling problems during product formulation. The exposure of tagatose to elevated relative humidities and temperatures should be avoided to maintain its physical and chemical quality. © 2012 Institute of Food Technologists®

  15. Compaction of amorphous iron–boron powder

    DEFF Research Database (Denmark)

    Hendriksen, Peter Vang; Mørup, Steen; Koch, Christian

    1993-01-01

    Large scale practical use of bulk amorphous alloys requires the capability of molding the material to a desired design, for instance by compaction of an amorphous powder. This is a difficult task because the sintering temperature is limited by the crystallization temperature of the alloy.1 Here w...... of density and structure on compaction pressure and compaction temperature. Journal of Applied Physics is copyrighted by The American Institute of Physics....

  16. PRODUCTION OF LEAD-FREE SOLDER POWDERS

    OpenAIRE

    Mustafacan , Kutsal

    2014-01-01

    The intentional use of conventional tin-lead (Sn-Pb) solder alloys was restricted with legislations across the world due to the toxic nature and the adverse effects of lead on health and the environment. Consequently, the development of new lead-free solder alloys has become a significant area of research. In addition to these health concerns, the continuing miniaturization trend of the consumer electronics has been pushing the production of solders from bulk form to powder form. In this stud...

  17. Modeling dissolution of sparingly soluble multisized powders

    OpenAIRE

    Almeida, Luís Pereira de; Simões, Sérgio; Brito, Paulo; Portugal, António; Figueiredo, Margarida

    1997-01-01

    The dissolution of powder drugs, besides being a topic of utmost importance, especially for the sparingly soluble ones, is far from being well-explained. The purpose of the present study is, on the one hand, to obtain experimental dissolution profiles and, on the other hand, to analyze and process the data for dissolution modeling. Three different size fractions of a widely used sparingly soluble drug - ibuprofen - were fully characterized with regard to its particle size distribution, specif...

  18. Powder-Metallurgical Bearings For Turbopumps

    Science.gov (United States)

    Bhat, B. N.; Humphries, T. S.; Thom, R. L.; Moxson, V.; Friedman, G. I.; Dolan, F. J.; Shipley, R. J.

    1993-01-01

    Bearings fabricated by powder metallurgy developed for use in machines subjected to extremes of temperature, rolling-contact cyclic stresses, and oxidizing or otherwise corrosive fluids. Bearings also extend operating lives of other machines in which bearings required to resist extreme thermal, mechanical, and chemical stresses. One alloy exhibiting outstanding properties was MRC-2001. Resistance to fatigue, stress corrosion cracking, and wear found superior to that of 440C stainless steel.

  19. Raman and dielectric studies of GdMnO3 bulk ceramics synthesized from nano powders

    Science.gov (United States)

    Samantaray, S.; Mishra, D. K.; Roul, B. K.

    2017-05-01

    Nanocrystalline GdMnO3 (GMO) powders has been synthesized by a simple chemical route i. e. pyrophoric reaction technique and then sintered in the form of bulk pellet at 850°C for 24 hours by adopting slow step sintering schedule. It is observed that by reducing the particles size, chemical route enhances the mixing process as well as decreasing the sintering temperature to get single phase material system in compared to the polycrystalline sample prepared directly from the micron sized commercial powder. Raman spectroscopic studies confirm that the sample is in single phase without any detectable impurity. Frequency dependent dielectric properties i.e., dielectric constant (K) and dielectric loss (tanδ) of GMO ceramics sintered at 850°C for 24 hours were studied at room temperature. The sample showed high K value (˜2736) in the frequency of 100 Hz at room temperature.

  20. Low-Flow-Rate Dry-Powder Feeder

    Science.gov (United States)

    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.

  1. Preparation and utilization of metal oxide fine powder

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    Metal oxide fine powders are used as new materials in many industrial fields. It is necessary to develop the technology for manufacturing such powders to improve the domestic industry. The purpose of present research is to develop technologies for the preparation and utilization of metal oxide fine powders. This research project is consisted of two main subjects. One is to develop processing technology on ultrafine silica powder of less than 100 nanometer in particle size, the other is on antimony trioxide powder which is used as flame retardant in plastic rubber, and textile industries. (author). 46 refs., 19 tabs., 35 figs.

  2. Combined experimental powder X-ray diffraction and DFT data to obtain the lowest energy molecular conformation of friedelin

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Djalma Menezes de; Mussel, Wagner da Nova; Duarte, Lucienir Pains; Silva, Gracia Divina de Fatima; Duarte, Helio Anderson; Gomes, Elionai Cassiana de Lima [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Guimaraes, Luciana [Universidade Federal de Sao Joao Del-Rei (UFSJ), MG (Brazil). Dept. de Ciencias Naturais; Vieira Filho, Sidney A., E-mail: bibo@ef.ufop.br [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Dept. de Farmacia

    2012-07-01

    Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer. (author)

  3. Combined experimental powder X-ray diffraction and DFT data to obtain the lowest energy molecular conformation of friedelin

    Directory of Open Access Journals (Sweden)

    Djalma Menezes de Oliveira

    2012-01-01

    Full Text Available Friedelin molecular conformers were obtained by Density Functional Theory (DFT and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single-crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer.

  4. Modeling of Powder Bed Manufacturing Defects

    Science.gov (United States)

    Mindt, H.-W.; Desmaison, O.; Megahed, M.; Peralta, A.; Neumann, J.

    2017-09-01

    Powder bed additive manufacturing offers unmatched capabilities. The deposition resolution achieved is extremely high enabling the production of innovative functional products and materials. Achieving the desired final quality is, however, hampered by many potential defects that have to be managed in due course of the manufacturing process. Defects observed in products manufactured via powder bed fusion have been studied experimentally. In this effort we have relied on experiments reported in the literature and—when experimental data were not sufficient—we have performed additional experiments providing an extended foundation for defect analysis. There is large interest in reducing the effort and cost of additive manufacturing process qualification and certification using integrated computational material engineering. A prerequisite is, however, that numerical methods can indeed capture defects. A multiscale multiphysics platform is developed and applied to predict and explain the origin of several defects that have been observed experimentally during laser-based powder bed fusion processes. The models utilized are briefly introduced. The ability of the models to capture the observed defects is verified. The root cause of the defects is explained by analyzing the numerical results thus confirming the ability of numerical methods to provide a foundation for rapid process qualification.

  5. New generation concretes including reactive powder concretes

    Directory of Open Access Journals (Sweden)

    Stefania Grzeszczyk

    2015-09-01

    Full Text Available Based on a broad literature review, this paper presents characteristics of new generation composites on the basis of cements which are applied in engineering structures and in rehabilitation of structures. The role of cement, microfillers, superplasticizers and fibers in the above stated composites i.e. factors which allow for the maximum packing of particles in the cement matrix and a minimum pore volume, and the increase in composite bending strength, have been discussed. Special attention was paid to Reactive Powder Concrete in which coarse aggregate was replaced by ground quartz and sand. Such composites contain active microfillers and the applied new-generation superplasticizers allow us to decrease the water-cement ratio in the composite up to 0.2. Whereas, steel fibre additive allows us to significantly improve the bending strength.The paper presents the properties of the excellent Ductal — a composite from Reactive Powder Concrete, which at compressive strength from 180 to 230 MPa achieves the tensile strength of 30 to 50 MPa. Its application allows us to create slim profiles and tall light and slender, and simultaneously durable and corrosion-resistant structural elements of considerable span. This paper gives a few examples of Ductal application in practice.[b]Keywords[/b]: civil engineering, composite materials, reactive powder concrete

  6. Shewanella strain isolated from black powder

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbach, Marcia T.S.; Contador, Luciana S.; Oliveira, Ana Lucia C.; Galvao, Mariana M. [National Institute of Technology (INT), Rio de Janeiro, RJ (Brazil); Pimenta, Gutemberg S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Black powder is a term frequently used to refer to residues formed by various types of iron sulfides mixed with contaminants eventually present in the natural gas flow. According to some researchers, the occurrence of black powder in gas pipelines, besides its chemical corrosion origin, can be directly related to the sulfate-reducing bacteria (SRB) metabolism in this environment. A black powder sample was inoculated in a Post gate E medium modified with the addition of thioglycolate. The resulting positive culture was kept in the laboratory for four years until its use. A dilution technique was then performed aiming to isolate an SRB strain. The bacterial strain isolated and identified through DNA sequencing was not an SRB but rather a Shewanella sp. Compared to the sulfate-reducing bacteria group-traditionally considered the foremost responsible for microbially-influenced corrosion (MIC) - Shewanella is a facultative anaerobe and has a versatile metabolism. Shewanella is able to reduce ferric iron and sulfite, oxidize hydrogen gas, and produce hydrogen sulfide; therefore, these bacteria can be responsible for MIC and pit formation. The isolated Shewanella was used in a corrosion experiment, and the corrosion products were characterized by X-ray diffraction, identifying iron sulfides, iron oxides, and sulfur. Our results indicate that the strain isolated, S. putrefaciens, plays a key role in corrosion problems in gas pipelines. (author)

  7. Moisture sorption of Thai red curry powder

    Directory of Open Access Journals (Sweden)

    Sudathip Inchuen

    2009-12-01

    Full Text Available Moisture sorption study was conducted on Thai red curry powder prepared by two different drying methods, viz. microwave and hot-air drying. Moisture sorption isotherms of the red curry powder at 30 C and water activity in the range of 0.113-0.970 were determined by a static gravimetric method. The isotherms exhibited Type III behaviour. The moisture sorption data were fitted to several sorption models and a non-linear regression analysis method was used to evaluate the constants of the sorption equations. The fit was evaluated using the coefficient of determination (R2, the reduced chi-square (2 and the root mean square error (RMSE. The GAB model followed by the Lewiski-3 model gave the best fit to the experimental data. The monolayer moisture content, taken as the safe minimum moisture level in the red curry powder, was determined using the BET equation and was found to range between 0.080 - 0.085 gram water per gram dry matter.

  8. [Making tablets of powdered milk and the physical properties].

    Science.gov (United States)

    Shibata, Mitsuho; Otsubo, Kazumitsu; Nakane, Shota; Niwa, Toshiyuki; Danjo, Kazumi

    2011-01-01

    Compressed baby milk powder has proven to be very convenient for parents due to the ease with which it can be handled, and the fact that use of a measuring scoop is not necessary. The purpose of this study was to develop a compressed baby milk powder and analyze the resulting physical properties. The basic production process consisted of the following steps: 1) molding milk powder by low compression pressure, 2) humidification at 25°C·97%RH and 3) drying with use of a desiccant. No chemical additives were used for solidification; therefore the chemical composition of the compressed milk powder is identical to the base milk powder. The important properties of the compressed milk powder are both ready solubility and the strength of the solid. The compressed milk powder obtained at low pressure was too brittle for practical use, but the strength was increased by humidification followed by drying. During the humidification process, the powder particles located close to the surface of the compressed milk powder partially dissolve resulting in bridging structures between the particles, leading to an increase in strength. Both specific surface area and the volume ratio of the compressed milk powder decreased. Testing showed that caking between the particles occurred following humidification, and that the volume of caking affected the ease with which the compressed milk powder dissolves in water.

  9. Experimental observations of dry powder inhaler dose fluidisation.

    Science.gov (United States)

    Tuley, Rob; Shrimpton, John; Jones, Matthew D; Price, Rob; Palmer, Mark; Prime, Dave

    2008-06-24

    Dry powder inhalers (DPIs) are widely used to deliver respiratory medication as a fine powder. This study investigates the physical mechanism of DPI operation, assessing the effects of geometry, inhalation and powder type on dose fluidisation. Patient inhalation through an idealised DPI was simulated as a linearly increasing pressure drop across three powder dose reservoir geometries permitting an analysis of shear and normal forces on dose evacuation. Pressure drop gradients of 3.3, 10 and 30 kPa s(-1)were applied to four powder types (glass, aluminium, and lactose 6 and 16% fines) and high speed video of each powder dose fluidisation was recorded and quantitatively analysed. Two distinct mechanisms are identified, labelled 'fracture' and 'erosion'. 'Fracture' mode occurs when the initial evacuation occurs in several large agglomerates whilst 'erosion' mode occurs gradually, with successive layers being evacuated by the high speed gas flow at the bed/gas interface. The mechanism depends on the powder type, and is independent of the reservoir geometries or pressure drop gradients tested. Both lactose powders exhibit fracture characteristics, while aluminium and glass powders fluidise as an erosion. Further analysis of the four powder types by an annular shear cell showed that the fluidisation mechanism cannot be predicted using bulk powder properties.

  10. Whey protein/polysaccharide-stabilized oil powders for topical application-release and transdermal delivery of salicylic acid from oil powders compared to redispersed powders.

    Science.gov (United States)

    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.

  11. X-ray luminescence of BaF 2:Ce 3+ powders

    OpenAIRE

    BATYGOV S. KH.; MAYAKOVA M.N.; S. V. Kuznetsov; Fedorov, P. P.

    2014-01-01

    We studied the mechanism for the formation of ceriumactivated barium fluoride scintillation ceramics and especially X-ray luminescence of its powdered precursors, prepared by coprecipitation of barium and cerium fluorides from aqueous solutions. We have found that the Ce 3+ luminescence, which is typical for cerium (III)-containing ceramics and single crystals, was not observed for such polycrystalline precursors, and the intensity of barium fluoride’s own luminescence decreases with increasi...

  12. Bimodal metal micro-nanopowders for powder injection molding

    Science.gov (United States)

    Pervikov, Aleksandr; Rodkevich, Nikolay; Glazkova, Elena; Lerner, Marat

    2017-12-01

    The paper studies a bimodal metal powder composition designed to prepare feedstock for powder injection molding, as well as microstructure and porosity of sintered pats. Two kinds of metal powder compositions are used, in particular, a mixture of micro- and nanopowders and a bimodal powder prepared with dispersion of steel wire. The feedstock is prepared by mixing a bimodal metal powder composition with acetylacetone and paraffin wax. The microstructure of the debound parts is observed by scanning electron microscopy. The sintered parts are characterized by density measurements and metallographic analysis. The technique of the metal powder composition proves to affect the characteristics of sintered parts. Nanoparticles are shown in the interstitial spaces among the microparticles upon mixing micro- and nanopowders, but the regular distribution of nanoparticles on the surface of microparticles is observed in the bimodal powder providing the reduction of the porosity of sintered parts and increasing the density to the proper density of steel.

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

    Science.gov (United States)

    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. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Powder dispersion mechanisms within a dry powder inhaler using microscale particle image velocimetry.

    Science.gov (United States)

    Kou, Xiang; Wereley, Steven T; Heng, Paul W S; Chan, Lai Wah; Carvajal, M Teresa

    2016-12-05

    The goal of this work was to evaluate the ability of Particle Image Velocimetry (PIV) to visually assess dry powder dispersion within an inhaler. Herein, the study reports particle movement characterization of entrained low-micron particles within an inhaler to further scheme of potential mechanisms. Carrier based DPI formulations were prepared and placed in a transparent model Rotahaler(®) chamber for the aerosolization experiments. Then using the PIV, a high-speed camera, the dried powder dispersion was directly observed and analyzed for all, neat, binary and ternary systems. Powder dispersion mechanisms proposed include drag force, impact with obstacle and particle-particle collision; these different mechanisms depended on the powder flow properties. A revised ratio of aerodynamic response time (τA) to the mean time between collisions (τC) was found to be 6.8 indicating that particle collisions were of strong influence to particle dispersion. With image analysis techniques, visualization of particle flow pattern and collision regions was possible; suggesting that the various mechanisms proposed did govern the powder dispersion. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Kilogram-scale production of SnO(2) yolk-shell powders by a spray-drying process using dextrin as carbon source and drying additive.

    Science.gov (United States)

    Choi, Seung Ho; Kang, Yun Chan

    2014-05-05

    A simple and general method for the large-scale production of yolk-shell powders with various compositions by a spray-drying process is reported. Metal salt/dextrin composite powders with a spherical and dense structure were obtained by spray drying and transformed into yolk-shell powders by simple combustion in air. Dextrin plays a key role in the preparation of precursor powders for fabricating yolk-shell powders by spray drying. Droplets containing metal salts and dextrin show good drying characteristics even in a severe environment of high humidity. Sucrose, glucose, and polyvinylpyrrolidone are widely used as carbon sources in the preparation of metal oxide/carbon composite powders; however, they are not appropriate for large-scale spray-drying processes because of their caramelization properties and adherence to the surface of the spray dryer. SnO2 yolk-shell powders were studied as the first target material in the spray-drying process. Combustion of tin oxalate/dextrin composite powders at 600 °C in air produced single-shelled SnO2 yolk-shell powders with the configuration SnO2 @void@SnO2 . The SnO2 yolk-shell powders prepared by the simple spray-drying process showed superior electrochemical properties, even at high current densities. The discharge capacities of the SnO2 yolk-shell powders at a current density of 2000 mA g(-1) were 645 and 570 mA h g(-1) for the second and 100th cycles, respectively; the corresponding capacity retention measured for the second cycle was 88 %. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Luminescence of aqueous reactions derived NiWO{sub 4} powders and sol-gel deposited films

    Energy Technology Data Exchange (ETDEWEB)

    He, Haiyan [Shaanxi University of Science and Technology (China). College of Materials Science and Engineering

    2010-03-15

    NiWO{sub 4} powders have been synthesized by reaction between NiCl{sub 2} and Na{sub 2}WO{sub 4} aqueous solutions and following calcinations at different temperatures. X-ray diffraction and scanning electron microscopy analysis were used to characterize the powders. Single phase NiWO{sub 4} powders were formed above a calcining temperature of 600 C. X-ray diffraction analysis indicated that the NiWO{sub 4} powders had a monoclinic structure and particle size of 26.8 nm and 30.3 nm for calcining temperatures of 600 C and 700 C, respectively. A little increase in intensity of the X-ray diffraction peaks was observed when increasing the calcining temperature from 600 C to 700 C. Scanning electron microscopy indicated that powders had uniform and very small particle size. The powders showed a broad blue-green emission band. The broad band of NiWO{sub 4} powders calcined at 600 C consisted of 423.2 nm (2.93 eV), 487.3 nm (2.54 eV) and two weak bands at 447.0 nm (2.77 eV), and 532.0 nm (2.33 eV). Small shifts in the peaks of excitation and luminescence and small increases in intensities were observed when increasing calcining temperature to 700 C. The films were deposited using the sol-gel method and using the precipitate as starting materials. The deposited films showed a similar blue-green emission to that of the powders. (orig.)

  17. Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

    Energy Technology Data Exchange (ETDEWEB)

    Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

    2018-02-06

    The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance against corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.

  18. HYDRATION PROCESS AND MECHANICAL PROPERTIES OF CEMENT PASTE WITH RECYCLED CONCRETE POWDER AND SILICA SAND POWDER

    Directory of Open Access Journals (Sweden)

    Jaroslav Topič

    2017-11-01

    Full Text Available Recycled concrete powder (RCP mostly consisting of cement paste could be reused as partial cement replacement. The aim of this paper is to compare hydration and mechanical properties of RCP and two types of silica sand powder (SSP. Comparison of those materials combined with cement can highlight the binder properties of recycled concrete powder. Using of two types of SSP also show an influence of their fines on hydration process and mechanical properties. Particle size analysis and calorimetric measurement were carried out and mechanical properties such as bulk density, dynamic Young’s modulus and compression strength were examine. Calorimetric measurement proves the presence of exposed non-hydrated particles in RCP that can react again. However lower density of old cement paste in RCP overweight the mentioned potential of RCP and mechanical properties are decreasing compared with reference cement paste and cement paste SSP.

  19. Validation of molecular crystal structures from powder diffraction data with dispersion-corrected density functional theory (DFT-D)

    DEFF Research Database (Denmark)

    van de Streek, Jacco; Neumann, Marcus A

    2014-01-01

    In 2010 we energy-minimized 225 high-quality single-crystal (SX) structures with dispersion-corrected density functional theory (DFT-D) to establish a quantitative benchmark. For the current paper, 215 organic crystal structures determined from X-ray powder diffraction (XRPD) data and published...

  20. The Quantitative Determination of Food Dyes in Powdered Drink Mixes: A High School or General Science Experiment

    Science.gov (United States)

    Sigmann, Samuella B.; Wheeler, Dale E.

    2004-01-01

    The development of a simple spectro photometric method to quantitatively determine the quantity of FD&C color additives present in powdered drink mixes, are focused by the investigations. Samples containing single dyes of binary mixtures of dyes can be analyzed using this method.

  1. A comparison between spray drying and spray freeze drying to produce an influenza subunit vaccine powder for inhalation

    NARCIS (Netherlands)

    Saluja, V.; Amorij, J-P.; Kapteyn, J. C.; de Boer, A. H.; Frijlink, H. W.; Hinrichs, W. L. J.

    2010-01-01

    The aim of this study was to investigate two different processes to produce a stable influenza subunit vaccine powder for pulmonary immunization i.e. spray drying (SD) and spray freeze drying (SFD). The formulations were analyzed by proteolytic assay, single radial immunodiffusion assay (SRID),

  2. Effects of Rare Earth Elements on Properties of Ni-Base Superalloy Powders and Coatings

    Directory of Open Access Journals (Sweden)

    Chunlian Hu

    2017-02-01

    Full Text Available NiCrMoY alloy powders were prepared using inert gas atomization by incorporation of rare earth elements, such as Mo, Nb, and Y into Ni60A powders, the coatings were sprayed by oxy-acetylene flame spray and then remelted with high-frequency induction. The morphologies, hollow particle ratio, particle-size distribution, apparent density, flowability, and the oxygen content of the NiCrMoY alloy powders were investigated, and the microstructure and hardness of the coatings were evaluated by optical microscopy (OM. Due to incorporation of the rare earth elements of Mo, Nb, or Y, the majority of the NiCrMoY alloy particles are near-spherical, the minority of which have small satellites, the surface of the particles is smoother and hollow particles are fewer, the particles exhibit larger apparent density and lower flowability than those of particles without incorporation, i.e., Ni60A powders, and particle-size distribution exhibits a single peak and fits normal distribution. The microstructure of the NiCrMoY alloy coatings exhibits finer structure and Rockwell hardness HRC of 60–63 in which the bulk- and needle-like hard phases are formed.

  3. Mixture of fuels for solution combustion synthesis of porous Fe3O4 powders

    Science.gov (United States)

    Parnianfar, H.; Masoudpanah, S. M.; Alamolhoda, S.; Fathi, H.

    2017-06-01

    The solution combustion synthesis of porous magnetite (Fe3O4) powders by a mixture of glycine and urea fuels was investigated concerning the thermodynamic aspects and powder characteristics. The adiabatic combustion temperature and combusted species were thermodynamically calculated as a function of the fuel to oxidant molar ratio (ϕ). The combustion behavior, phase evolution, porous structure and magnetic properties were characterized by thermal analysis, X-ray diffractometry, N2 adsorption-desorption, electron microscopy and vibrating sample magnetometry techniques. Nearly single phase Fe3O4 powders were synthesized by the mixture of fuels at ϕ values of 0.75 and 1. The as-combusted Fe3O4 powders at ϕ = 1 exhibited porous structure with the specific surface area of 83.4 m2/g. The highest saturation magnetization of 75.5 emu/g and the lowest coercivity of 84 Oe were achieved at ϕ = 1, due to the high purity and large crystallite size, inducing from the highest adiabatic combustion temperature.

  4. Prediction of bulk powder flow performance using comprehensive particle size and particle shape distributions.

    Science.gov (United States)

    Yu, Weili; Muteki, Koji; Zhang, Lin; Kim, Gloria

    2011-01-01

    The purpose of this study is to establish a modeling approach that can be used to predict bulk powder flowability of pharmaceutical materials from their particle size and shape distributions. To build and validate the model, 23 commonly used pharmaceutical excipients and 38 binary blends were fully characterized for their particle size and shape distributions. The particle size and shape of each sample was characterized by multiple descriptors to fully reflect their morphological characteristics. The flow properties of these materials were analyzed using the Schulze Ring Shear Tester at a fixed humidity condition. A partial least squares (PLS) approach was used to build the mathematical model. Several different modeling approaches were attempted and the best method was identified as using a combination of formulation composition and particle size and shape distributions of single-component powder systems. The PLS model was shown to provide excellent predictions of powder flow function coefficient (FFC) of up to approximately 20. The results also revealed that both particle size and shape play an important role in determining the powder flow behavior. Copyright © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

  5. Developing Characterization Procedures for Qualifying both Novel Selective Laser Sintering Polymer Powders and Recycled Powders

    Energy Technology Data Exchange (ETDEWEB)

    Bajric, Sendin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-12

    Selective laser sintering (SLS) is an additive technique which is showing great promise over conventional manufacturing techniques. SLS requires certain key material properties for a polymer powder to be successfully processed into an end-use part, and therefore limited selection of materials are available. Furthermore, there has been evidence of a powder’s quality deteriorating following each SLS processing cycle. The current investigation serves to build a path forward in identifying new SLS powder materials by developing characterization procedures for identifying key material properties as well as for detecting changes in a powder’s quality. Thermogravimetric analyses, differential scanning calorimetry, and bulk density measurements were investigated.

  6. Large Bore Powder Gun Qualification (U)

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Powder processing of hybrid titanium neural electrodes

    Science.gov (United States)

    Lopez, Jose Luis, Jr.

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

  8. Modeling Li-ion conductivity in LiLa(PO{sub 3}){sub 4} powder

    Energy Technology Data Exchange (ETDEWEB)

    Mounir, Ferhi, E-mail: ferhi.mounir@gmail.com [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia); Karima, Horchani-Naifer [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia); Khaled, Ben Saad [Laboratoire de Photovoltaieque, Centre des Recherches et des Technologies de l' Energie, Technopole Borj Cedria, BP No. 95, 2050 Hammam Lif (Tunisia); Mokhtar, Ferid [Laboratoire de Physicochimie des Materiaux Mineraux et leurs Applications, Centre National des Recherches en Sciences des Materiaux, BP No. 73, 8027 Soliman (Tunisia)

    2012-07-01

    Polycrystalline powder and single-crystal of LiLa(PO{sub 3}){sub 4} are synthesized by solid state reaction and flux technique, respectively. A morphological description of the obtained product was made based on scanning electron microscopy micrographs. The obtained powder was characterized by X-ray powder diffraction, FTIR and Raman spectroscopies. Ionic conductivity of the LiLa(PO{sub 3}){sub 4} powder was measured and evaluated over a temperature range from 553 to 913 K. Single crystals of LiLa(PO{sub 3}){sub 4} are characterized by single-crystal X-ray diffraction. The LiLa(PO{sub 3}){sub 4} structure was found to be isotypic with LiNd(PO{sub 3}){sub 4}. It crystallizes in the monoclinic system with space group C2/c and cell parameters: a=16.635(6) A, b=7.130(3) A, c=9.913(3) A, {beta}=126.37(4) Degree-Sign , V=946.72(6) A{sup 3} and Z=4. The LiLa(PO{sub 3}){sub 4} structure was described as an alternation between spiraling chains (PO{sub 3}){sub n} and (La{sup 3+}, Li{sup +}) cations along the b direction. The small Li{sup +} ions, coordinated to four oxygen atoms, were located in the large connected cavities created between the LaO{sub 8} polyhedra and the polyphosphate chains. The jumping of Li{sup +} through tunnels of the crystalline network was investigated using complex impedance spectroscopy. The close value of the activation energies calculated through the analysis of conductivity data and loss spectra indicate that the transport in the investigated system is through hopping mechanism. The correlation between ionic conductivity of LiLa(PO{sub 3}){sub 4} and its crystallographic structure was investigated and the most probably transport pathway model was determined.

  9. Ampicillin Trihydrate from Synchrotron Powder Diffraction Data

    Energy Technology Data Exchange (ETDEWEB)

    Burley,J.; van de Streek, J.; Stephens, P.

    2006-01-01

    The crystal structure of ampicillin trihydrate {l_brace}systematic name: 6-[D(-)-{alpha}-aminophenylacetamido]penicillanic acid trihydrate{r_brace}, C{sub 16}H{sub 19}N{sub 3}O{sub 4}S{center_dot}3H{sub 2}O, a broad-spectrum {beta}-lactam antibiotic of the aminopenicillin type, has been determined from synchrotron X-ray powder diffraction data. The three water molecules form an infinite hydrogen-bonded chain through the crystal structure, with hydrogen bonds to the NH{sub 3}{sup +}, COO{sup -}, C{double_bond}O and NH groups of the ampicillin molecules.

  10. Borax as a lubricant in powder metallurgy

    Directory of Open Access Journals (Sweden)

    Héctor Geovanny Ariza-Suarez

    2014-12-01

    were compacted at 700 MPa in a uniaxial press of 15 tons. DSC-TGA analysis of the mixture with borax was realized. The specimens were sintered in a plasma reactor at 1000 for 30 minutes, with a combined atmosphere of hydrogen and argon. Microhardness and density of the sintered samples was haracterized. XRD analysis was realized to detect possible compounds formation by interaction of borax. This paper shows that borax can be used as a lubricant in powder metallurgy.

  11. Conversion of Nitrocellulose to Smokeless Powder

    Science.gov (United States)

    1941-01-17

    Z.Ges.Schless-Sprengstoffw. 30,36l-1*-(l935) New Nitrocellulose Powders and Explosives g. S.ölückmann. Kunststoffe 25:25-29,120-23(1935) The Viscosity and... Kunststoffe 2^,32-5^(193^-) New Solvents and Plasticizers for Nitrocellulose 22. T.Tomonarl. J.Soc.Chem.Ind..Japan 37,Supp.775-7(1934) Classification of...L.Rutsteln. Kunststoffe 11,25-23(1921) The Viscosity of Nitrocellulose R.Robertson. Trans.Far.3oc. 16,66-71 (1921) Nitrocellulose F.Soroxton

  12. Surface free energy characterization of powders

    Science.gov (United States)

    Yildirim, Ismail

    2001-12-01

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

  13. [Easyhaler--ideal dry powder inhaler].

    Science.gov (United States)

    Andrzej, Emeryk; Małgorzata, Bartkowiak-Emeryk

    2010-04-01

    Dry powder inhalers (DPI) differ among each other in many technical aspects, size and value of lung deposition as well as clinical efficacy of inhaled drugs. Easyhaler is a reservoir, multi-dose, high-resistance DPI and it is easy to operate. The device needs low inspiratory flows which are possible to achieve even by asthmatic children over 5-year-old and emitted dose and fine particle fraction are practically stable within the range of optimal inspiratory flows. Currently budesonid, formoterol and salbutamol are available in Easyhaler device form. Easyhaler is accepted by majority of patients with asthma or COPD.

  14. Powder neutron diffractometers HRPT and DMCG

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P.; Doenni, A.; Staub, U.; Zolliker, M. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    Basic properties and applications of SINQ powder neutron diffractometers are described. For optimum use of the continuous neutron beams these instruments are equipped with position sensitive detectors, and both high-intensity and high-resolution modes of operation are possible. HRPT attaining resolutions {delta}d/d{<=}10{sup -3}, d=lattice spacing, at a thermal neutron channel of the target station and DMCG at a cold neutron guide coated with m=2 supermirrors, are complementary concerning the applications: the former will be mainly used for structural studies and the latter to investigate magnetic ordering phenomena. (author) figs., tabs., refs.

  15. Physical properties of yoghurt powder produced by spray drying.

    Science.gov (United States)

    Koç, Banu; Sakin-Yılmazer, Melike; Kaymak-Ertekin, Figen; Balkır, Pınar

    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 μm, respectively.

  16. POWDER INJECTION MOLDING OF SIC FOR THERMAL MANAGEMENT V

    Directory of Open Access Journals (Sweden)

    Valmikanathan Onbattuvelli

    2012-06-01

    Full Text Available Silicon carbide (SiC exhibits many functional properties that are relevant to applications in electronics, aerospace, defense and automotive industries. However, the successful translation of these properties into final applications lies in the net-shaping of ceramics into fully dense microstructures. Increasing the packing density of the starting powders is one effective route to achieve high sintered density and dimensional precision. The present paper presents an in-depth study on the effects of nanoparticle addition on the powder injection molding process (PIM of SiC powder-polymer mixtures. In particular, bimodal mixtures of nanoscale and sub-micrometer particles are found to have significantly increased powder packing characteristics (solids loading in the powder-polymer mixtures. The influence of nanoparticle addition on the multi-step PIM process is examined. The above results provide new perspectives which could impact a wide range of materials, powder processing techniques and applications.

  17. Production of functional pita bread using date seed powder.

    Science.gov (United States)

    Platat, Carine; Habib, Hosam M; Hashim, Isameldin Bashir; Kamal, Hina; AlMaqbali, Fatima; Souka, Usama; Ibrahim, Wissam H

    2015-10-01

    Functional foods represent a novel approach to prevent diet-related diseases. Due to its excellent nutritional and antioxidant properties, date seed was used to develop functional pita bread. Flour was replaced by 5, 10, 15 and 20 % date seed powder. Regular and whole wheat pita breads were the references. Results clearly showed that date seed powder containing bread contained comparable dietary fibers levels as in whole wheat bread and higher levels of flavonoids and phenolics. Date seed powder containing breads were particularly rich in flavan-3-ols whereas reference breads did not contain any of them and only a limited amount of other phenolic compounds. They also exhibited a much higher antioxidant capacity. Additionally, compared to regular bread, acrylamide level was significantly lower in 5 % date seed powder containing bread, and lower in all date seed powder containing breads compared to whole wheat bread. Date seed powder supplemented bread appears as a promising functional ingredient to prevent chronic diseases.

  18. Transient liquid-phase bonding using coated metal powders

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, W.D.; Eagar, T.W. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

    1997-04-01

    Powder particles coated with a small amount of melting point depressant (MPD) reveal different sintering behavior in comparison to an uncoated powder mixture of the same composition. Interlayers consisting of the coated powder particles were used in the transient liquid-phase (TLP) bonding process. The coating material and the thickness of the deposit are important parameters that influence shrinkage. The amount of MPD was controlled such that the volume fraction of the liquid was very small but existed at all contacts, thus improving densification of the interlayer. Ni-20Cr and 304L stainless steel powders coated with Ni-10P were applied to join 304 stainless steels. Fully dense joints with mechanical properties comparable to those of the base metals were obtained with Ni-20Cr powder interlayers, whereas joints with 304L stainless steel powder interlayers showed inferior mechanical properties due to residual porosity in the joints.

  19. Preparation of nanosized non-oxide powders using diatomaceous earth

    Directory of Open Access Journals (Sweden)

    Šaponjić A.

    2009-01-01

    Full Text Available In this paper the nanosized non-oxide powders were prepared by carbothermal reduction and subsequent nitridation of diatomaceous earth which is a waste product from coal exploitation. Our scope was to investigate the potential use of diatomaceous earth as a main precursor for low-cost nanosized non-oxide powder preparation as well as to solve an environmental problem. The influence of carbon materials (carbonized sucrose, carbon cryogel and carbon black as a reducing agent on synthesis and properties of low-cost nanosized nonoxide powders was also studied. The powders were characterized by specific surface area, X-ray and SEM investigations. It was found that by using diatomaceous earth it is was possible to produce either a mixture of non-oxide powders (Si3N4/SiC or pure SiC powders depending on temperature.

  20. Quality changes of Antarctic krill powder during long term storage

    DEFF Research Database (Denmark)

    Nielsen, Nina Skall; Lu, Henna Fung Sieng; Bruheim, Inge

    2017-01-01

    Krill is a valuable sustainable resource of omega-3 fatty acids and protein, which may be processed into a krill powder for human consumption. The objective of this study was to investigate the stability of krill powder when stored for up to 12 months at room temperature. In addition, the effect......) is a shrimp-like marine crustacean. It is rich in omega-3 fatty acids, primarily bound in phospholipids in the sn-2 position of the molecule, making it highly bioavailable. Krill may be processed into powder also rich in protein and astaxanthin. Stability of krill powder, stored for up to 12 months at room...... and a concomitant decrease in antioxidants, tocopherol, and astaxanthin was observed. In addition, there was a minor decrease in phospholipids and n-3 fatty acids; however, storage at vacuum improved the oxidative stability of krill powder. Practical applications: For the use of krill powder in human nutrition...

  1. Ni Based Powder Reconditioning and Reuse for LMD Process

    Science.gov (United States)

    Renderos, M.; Girot, F.; Lamikiz, A.; Torregaray, A.; Saintier, N.

    LMD is an additive manufacturing process based on the injection of metallic powder into a melt-pool created by a heat laser source on a substrate. One of the benefits of this technology is the reduction of the wasted material since it is a near-shape process. Moreover one of the main drawbacks is the relatively low efficiency of the trapped powder, which can be loss than 5% in some cases. The non-trapped powder represents a significant cost in the LMD process, since powder metal material is very expensive and usually is not reused. This article proposes a methodology of the reconditioning and posterior reuse of a nickel base powder commonly used in the aerospace industry, with the main objectives of cost saving, higher environmental cleanup and increase of the overall efficiency in the LMD process. The results are checked by the development of a prototype part built up from reused powder.

  2. Method for preparing metal powder, device for preparing metal powder, method for processing spent nuclear fuel

    Science.gov (United States)

    Park, Jong-Hee [Clarendon Hills, IL

    2011-11-29

    A method for producing metal powder is provided the comprising supplying a molten bath containing a reducing agent, contacting a metal oxide with the molten bath for a time and at a temperature sufficient to reduce the metal in the metal oxide to elemental metal and produce free oxygen; and isolating the elemental metal from the molten bath.

  3. Risky business: pre-powdered gloves or powder-free gloves in the operating suite?

    Science.gov (United States)

    Spicer, M; Richardson, M

    1998-01-01

    Two of the emerging issues for the health-care sector in the 1990s are occupational health and safety, and iatrogenic issues. Both of these issues are implicated in the use of pre-powdered latex gloves. Hospital health-care workers are exposed to latex in many ways: gloves, intravenous sets, ventilator circuits, dental products, resuscitation equipment, anaesthetic equipment. Post-operative complications, delayed wound healing, scar formation, and the potential for misdiagnosis, in the presence of starch powder, have been well documented in the literature with the need for through glove rinsing prior to surgery. Another route for glove powder to enter wounds is through a barrier breach. For an institution to ensure it provides the most durable and effective barrier for healthcare worker protection and patient safety, knowledge is needed regarding the various factors which lead to glove barrier failure. The primary aim of the study was to evaluate the in-use durability of the surgical gloves in current use against powder-free gloves. Descriptive statistics were used to analyse the data, in addition a cost analysis was calculated. The results of this study demonstrated clinically important differences between existing glove products in terms of barrier quality.

  4. Laser-driven synthesis of SiC ceramic powders

    Energy Technology Data Exchange (ETDEWEB)

    Curcio, F.; Ghiglione, G.; Musci, M.; Nannetti, C.

    1989-01-01

    Ultrafine silicon carbide ceramic powders were produced by irradiating silane and acethylene mixtures with a CW carbon dioxide laser. The process and powder characteristics were studied against the most important experimental parameters. Sintering tests were done in order to evaluate the performance of the laser produced powders: densifications up to 99% of the theoretical value were achieved and metallographic analyses evidenced the superior quality of the best obtained specimens.

  5. Microwave Sintering of Electroless Ni Plated WC Powders

    OpenAIRE

    EROL, Ayhan; YONETKEN, Ahmet

    2010-01-01

    Nickel matrix reinforced with WC has been manufactured by microwave sintering at various temperatures. A uniform nickel layer on WC powders was deposited prior to sintering using electroless plating technique, allowing close surface contact than can be achieved using conventional methods such as mechanical alloying. The reactivity between WC powders to form compounds is controlled through Ni layer existing on the starting powders. A composite consisting of quaternary additions, a ceramic phas...

  6. Need for a comparative performance standard for dry powder inhalers.

    Science.gov (United States)

    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

  7. A major advance in powder metallurgy

    Science.gov (United States)

    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. Powdered tucupi condiment: sensory and hygroscopic evaluation

    Directory of Open Access Journals (Sweden)

    Telma dos Santos COSTA

    Full Text Available Abstract Tucupi is a fermented liquid obtained from cassava (Manihot esculenta Crantz, very much appreciated by the traditional cuisine of Northern Brazil. However, there are no scientific reports on its use in the formulation of products. Thus, the present study aimed to elaborate a powdered condiment with tucupi, as well as to assess the product’s sensory acceptability and its hygroscopic behavior. The powdered tucupi used in the formulation of the condiment was obtained by drying in a spray dryer. The product underwent sensory evaluation for its acceptability regarding the attributes of color, aroma, flavor, and overall impression and a purchase intention test was applied by hedonic scale. The acceptability index was 80% for overall impression and the purchase intention test indicated that 94% of the judges would be willing to buy the product. The product’s moisture sorption isotherms presented type-II behavior for adsorption and type-III for desorption, at 25 °C. The hygroscopic behavior indicated that the product is more susceptible to spoilage changes when stored in an environment with relative humidity above 60% and the Peleg model showed an excellent performance on predicting the product’s moisture sorption isotherms.

  9. Thermophotovoltaics, wood powder and fuel quality

    Energy Technology Data Exchange (ETDEWEB)

    Marks, J. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Operational Efficiency; Broman, L.; Jarefors, K. [Solar Energy Research Center, Borlaenge (Sweden)

    1998-06-01

    PV cells can be used for electricity production based on other heat sources than the sun. If the temperature of the source is around 1500 K it is possible to get reasonably high conversion efficiency from heat radiation to electricity. This is due to recent advances in low-bandgap PV cells and selectively emitting fibrous emissive burners. There are some different biomass fuels capable of producing this temperature in the flame, especially gas and liquid fuels of different kinds. Wood powder is the only solid wood fuel with a sufficiently stable quality and properties for this high temperature combustion. A joint project between SERC, SLU and National Renewable Energy Laboratory NREL in Golden, Colorado, USA aims at building a wood powder fuelled thermophotovoltaic (TPV) generator for cogeneration of heat and electricity. A stable flame temperature of 1500 K has been achieved in a prototype pilot-scale burner that includes feeder and combustion chamber. Furthermore, a setup for measuring TPV cell efficiency for a wide region of black body emitter temperatures and cell irradiation has been constructed and several 0.6 eV GaInAs TPV cells have been investigated. A setup for testing the chain IR emitter - selectively reflecting filter - TPV cell has been designed. In order to limit the region of filter incident angles, which will make the filter act more efficiently, a special geometry of the internally reflecting tube that transmits the radiation is considered 23 refs, 4 figs

  10. Synchrotron powder diffraction on Aztec blue pigments

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez del Rio, M. [European Synchrotron Radiation Facility, B.P. 220, Grenoble Cedex (France); Gutierrez-Leon, A.; Castro, G.R.; Rubio-Zuazo, J. [Spanish CRG Beamline at the European Synchrotron Radiation Facility, SpLine, B.P. 220, Grenoble Cedex (France); Solis, C. [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico, D.F. (Mexico); Sanchez-Hernandez, R. [INAH Subdireccion de Laboratorios y Apoyo Academico, Mexico, D.F. (Mexico); Robles-Camacho, J. [INAH Centro Regional Michoacan, Morelia, Michoacan (Mexico); Rojas-Gaytan, J. [INAH Direccion de Salvamento Arqueologico, Naucalpan de Juarez (Mexico)

    2008-01-15

    Some samples of raw blue pigments coming from an archaeological rescue mission in downtown Mexico City have been characterized using different techniques. The samples, some recovered as a part of a ritual offering, could be assigned to the late Aztec period (XVth century). The striking characteristic of these samples is that they seem to be raw pigments prior to any use in artworks, and it was possible to collect a few {mu}g of pigment after manual grain selection under a microscopy monitoring. All pigments are made of indigo, an organic colorant locally known as anil or xiuhquilitl. The colorant is always found in combination with an inorganic matrix, studied by powder diffraction. In one case the mineral base is palygorskite, a rare clay mineral featuring micro-channels in its structure, well known as the main ingredient of the Maya blue pigment. However, other samples present the minerals sepiolite (a clay mineral of the palygorskite family) and calcite. Another sample contains barite, a mineral never reported in prehispanic paints. We present the results of characterization using high resolution powder diffraction recorded at the European Synchrotron Radiation Facility (BM25A, SpLine beamline) complemented with other techniques. All of them gave consistent results on the composition. A chemical test on resistance to acids was done, showing a high resistance for the palygorskite and eventually sepiolite compounds, in good agreement with the excellent resistance of the Maya blue. (orig.)

  11. Modeling dissolution of sparingly soluble multisized powders.

    Science.gov (United States)

    de Almeida, L P; Simöes, S; Brito, P; Portugal, A; Figueiredo, M

    1997-06-01

    The dissolution of powder drugs, besides being a topic of utmost importance, especially for the sparingly soluble ones, is far from being well-explained. The purpose of the present study is, on the one hand, to obtain experimental dissolution profiles and, on the other hand, to analyze and process the data for dissolution modeling. Three different size fractions of a widely used sparingly soluble drug--ibuprofen--were fully characterized with regard to its particle size distribution, specific surface area, density, solubility, and diffusion coefficient. The dissolution profiles were obtained making use of a technique that counts and sizes particles--the Coulter counter technique--which is capable of following the number and size of the particles in suspension throughout time. The knowledge of these parameters allowed a critical study of the assumptions associated with the models currently used to describe the dissolution process. It was concluded that most of the assumptions were not valid for the present experimental conditions. This motivated the proposal of a new methodology, which uses the experimentally determined characteristics of the drug and takes into account the polydisperse nature of the powder. By applying an adequate dissolution equation to each of the many size classes in which the primary particle size distribution was divided, it was possible to obtain a large agreement between the simulated and the experimental dissolution profile.

  12. An Acceptability Trial of Desiccated Beef Liver and Meat Powder as Potential Fortifiers of Complementary Diets of Young Children in Indonesia.

    Science.gov (United States)

    Duizer, Lisa M; Diana, Aly; Rathomi, Hilmi S; Luftimas, Dimas E; Rahmannia, Sofa; Santi, Widya; Nugraha, Gaga Irawan; Haszard, Jill J; Gibson, Rosalind S; Houghton, Lisa A

    2017-09-01

    The addition of desiccated beef liver to infant and young child complementary foods can be used to overcome nutrient deficits, however its acceptability is unknown. We conducted a series of studies to test the acceptability of complementary foods fortified with either powdered beef liver, beef meat, beef liver + meat or placebo among 96 Indonesian children aged 12 to 23 mo. This was achieved by determining liking of a single test food with added study powder, followed by a 2-wk home trial and focus group discussions to assess liking during repeated consumption of the study powders added to daily meals. The test food with added beef powders were well liked by mothers, with liking scores never falling below neutral on a 7-point scale. After home use, mothers reported that their children moderately liked their meals with added powder, with scores ranging between 3.3 and 3.5 on a 5-point scale. With the exception of lower liking for the combination beef liver + meat powder, there were no detectable differences in mothers' overall perception of child's liking between the placebo and any of the study powders. The low disappearance rate of the study powders during the home trial was a concern, with mothers reporting a strong smell and fishy odor as the major reason why children did not like their meals. Nonetheless, mothers declared they would continue using the powder on account of the nutritional value and perceived health benefits. Strategies are underway to minimize the level of fishy odor in the beef liver powder. © 2017 Institute of Food Technologists®.

  13. Abrasive Wear Resistance of Overlay Composite Alloy with Addition of Carbide Powders

    OpenAIRE

    Tadao, ARAKI; Minoru, NISHIDA; Akio, HIROSE; Kouji, YANO; HIroshi, FUJITA; Faculty of Eng., Ehime University; Faculty of Eng., Ehime University; Faculty of Eng., Osaka University; Kawasaki Steel Co., Ltd.; Tokuden Co., Ltd.

    1993-01-01

    The overall objective of this project is to provide data showing how carbide powder in addition to base alloy powder can be used effectively to increase hardness of overlay alloy and resistance to abrasive wear. An experimental study was performed to examine combinations of base alloy powders and reinforcing powders. The base alloy powders considered were stainless steel, Ni-base alloy, Co-base alloy and high speed steel powder, while reinforcing powders considered were metal-carbide and cera...

  14. Phytoene, Phytofluene, and Lycopene from Tomato Powder Differentially Accumulate in Tissues of Male Fisher 344 Rats.

    Science.gov (United States)

    Campbell, Jessica K; Engelmann, Nancy J; Lila, Mary Ann; Erdman, John W

    2007-12-01

    Tomato product consumption is inversely related to prostate cancer incidence, and lycopene (LYC) has been implicated in reduced prostate cancer risk. The contribution of other tomato carotenoids, phytoene (PE) and phytofluene (PF), towards prostate cancer risk has not been adequately studied. The relative uptake and tissue distribution of tomato carotenoids are not known. We hypothesize that PE and PF are bioavailable from a tomato powder diet or from a purified source and accumulate in androgen-sensitive tissues. In this study, 4 wk old male Fisher 344 rats were pre-fed an AIN-93G powder diet composed of 10% tomato powder containing PE, PF, and LYC (0.015, 0.012, and 0.011 g/kg diet, respectively). After 30 d tomato powder feeding, hepatic PF concentrations (168 ± 20 nmol/g) were higher than PE or LYC (104 ± 13 and 104 ± 13 nmol/g, respectively). In contrast, LYC, followed by PF, had the highest accumulation of the measured carotenoids in the prostate lobes and seminal vesicles. When tomato powder-fed rats received a single oral dose of either ∼2.7 mg PE or PF, an increase in the dosed carotenoid concentration was observed in all measured tissues, except the adrenal. Percent increases of PF were greater than that of PE in liver, serum, and adipose (37, 287 and 49% versus 16, 179 and 23%, respectively). Results indicate that the relative tomato carotenoid biodistribution differs in liver and androgen-sensitive tissues, suggesting that minor changes in the number of sequential double bonds in carotenoid structures alter absorption and/or metabolism of tomato carotenoids.

  15. NOTE: Effects of powder additives suspended in dielectric on crater characteristics for micro electrical discharge machining

    Science.gov (United States)

    Yeo, S. H.; Tan, P. C.; Kurnia, W.

    2007-11-01

    The effects of using powder additives suspended in dielectric on crater characteristics for micro electrical discharge machining (PSD micro-EDM) are investigated through the conduct of single RC discharge experiments at low discharge energies of 2.5 µJ, 5 µJ and 25 µJ. Through the introduction of additive particles into the dielectric, results of the single discharge experiments show the formation of craters with smaller diameters and depths, and having more consistent circular shapes than those produced in dielectric without additive. These craters also possess a noticeable morphological difference compared to those generated in dielectric without additive. In addition, discharge current measurements show a smaller amount of charges flowing between the tool electrode and workpiece, and at a slower flow rate when additives are present in the dielectric. Furthermore, based on the experimental results and findings from studies done in nanofluids, a hypothesis is made on the effects of powder suspended dielectric on the crater formation mechanism. The increased viscosity and enhanced thermal conductivity of a powder suspended dielectric lower the plasma heat flux into the electrode and raise the rate of heat dissipation away from the molten cavity. As a result, a smaller-sized crater having a larger amount of resolidified material within the crater cavity is formed.

  16. Synergy between transmission electron microscopy and powder diffraction: application to modulated structures.

    Science.gov (United States)

    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).

  17. Joining of parts via magnetic heating of metal aluminum powders

    Science.gov (United States)

    Baker, Ian

    2013-05-21

    A method of joining at least two parts includes steps of dispersing a joining material comprising a multi-phase magnetic metal-aluminum powder at an interface between the at least two parts to be joined and applying an alternating magnetic field (AMF). The AMF has a magnetic field strength and frequency suitable for inducing magnetic hysteresis losses in the metal-aluminum powder and is applied for a period that raises temperature of the metal-aluminum powder to an exothermic transformation temperature. At the exothermic transformation temperature, the metal-aluminum powder melts and resolidifies as a metal aluminide solid having a non-magnetic configuration.

  18. Time resolved fluorescence of cow and goat milk powder

    Science.gov (United States)

    Brandao, Mariana P.; de Carvalho dos Anjos, Virgílio; Bell., Maria José V.

    2017-01-01

    Milk powder is an international dairy commodity. Goat and cow milk powders are significant sources of nutrients and the investigation of the authenticity and classification of milk powder is particularly important. The use of time-resolved fluorescence techniques to distinguish chemical composition and structure modifications could assist develop a portable and non-destructive methodology to perform milk powder classification and determine composition. This study goal is to differentiate milk powder samples from cows and goats using fluorescence lifetimes. The samples were excited at 315 nm and the fluorescence intensity decay registered at 468 nm. We observed fluorescence lifetimes of 1.5 ± 0.3, 6.4 ± 0.4 and 18.7 ± 2.5 ns for goat milk powder; and 1.7 ± 0.3, 6.9 ± 0.2 and 29.9 ± 1.6 ns for cow's milk powder. We discriminate goat and cow powder milk by analysis of variance using Fisher's method. In addition, we employed quadratic discriminant analysis to differentiate the milk samples with accuracy of 100%. Our results suggest that time-resolved fluorescence can provide a new method to the analysis of powder milk and its composition.

  19. Nanocomposite Thermolectric Materials by High Pressure Powder Consolidation Manufacturing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA's need to develop advanced nanostructured thermolectric materials, UTRON is proposing an innovative high pressure powder consolidation...

  20. Forming gas treatment of lithium ion battery anode graphite powders

    Science.gov (United States)

    Contescu, Cristian Ion; Gallego, Nidia C; Howe, Jane Y; Meyer, III, Harry M; Payzant, Edward Andrew; Wood, III, David L; Yoon, Sang Young

    2014-09-16

    The invention provides a method of making a battery anode in which a quantity of graphite powder is provided. The temperature of the graphite powder is raised from a starting temperature to a first temperature between 1000 and 2000.degree. C. during a first heating period. The graphite powder is then cooled to a final temperature during a cool down period. The graphite powder is contacted with a forming gas during at least one of the first heating period and the cool down period. The forming gas includes H.sub.2 and an inert gas.

  1. Evaluation of ring shear testing as a characterization method for powder flow in small-scale powder processing equipment

    DEFF Research Database (Denmark)

    Søgaard, Søren Vinter; Pedersen, Troels; Allesø, Morten

    2014-01-01

    Powder flow in small-scale equipment is challenging to predict. To meet this need, the impact of consolidation during powder flow characterization, the level of consolidation existing during discharge of powders from a tablet press hopper and the uncertainty of shear and wall friction measurements...... at small consolidation stresses were investigated. For this purpose, three grades of microcrystalline cellulose were used. Results showed that powder flow properties depend strongly on the consolidation during testing. The consolidation during discharge in terms of the major principal stress and wall......, the wall and shear stress resolution influences the precision of the measured powder flow properties. This study highlights the need for an improved experimental setup which would be capable of measuring the flow properties of powders under very small consolidation stresses with a high shear stress...

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

    Science.gov (United States)

    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

  3. Energy-conscious production of titania and titanium powders from slag

    Science.gov (United States)

    Middlemas, Scott C.

    Titanium dioxide (TiO2) is used as a whitening agent in numerous domestic and technological applications and is mainly produced by the high temperature chloride process. A new hydrometallurgical process for making commercially pure TiO2 pigment is described with the goal of reducing the necessary energy consumption and CO2 emissions. The process includes alkaline roasting of titania slag with subsequent washing, HCl leaching, solvent extraction, hydrolysis, and calcination stages. The thermodynamics of the roasting reaction were analyzed, and the experimental parameters for each step in the new process were optimized with respect to TiO 2 recovery, final product purity, and total energy requirements. Contacting the leach solution with a tertiary amine extractant resulted in complete Fe extraction in a single stage and proved effective in reducing the concentration of discoloring impurities in the final pigment to commercially acceptable levels. Additionally, a new method of producing Ti powders from titania slag is proposed as a potentially more energy efficient and lower cost alternative to the traditional Kroll process. Thermodynamic analysis and initial experimental results validate the concept of reducing titanium slag with a metal hydride to produce titanium hydride (TiH2) powders, which are subsequently purified by leaching and dehydrided to form Ti powders. The effects of reducing agent type, heating time and temperature, ball milling, powder compaction, and eutectic chloride salts on the conversion of slag to TiH2 powders were determined. The purification of reduced powders through NH4Cl, NaOH, and HCl leaching stages was investigated, and reagent concentration, leaching temperature, and time were varied in order to determine the best conditions for maximum impurity removal and recovery of TiH2. A model plant producing 100,000 tons TiO2 per year was designed that would employ the new method of pigment manufacture. A comparison of the new process and the

  4. Growth of 2-amino-5-chlorobenzophenone single crystal by ...

    Indian Academy of Sciences (India)

    Abstract. Organic single crystals of 2-amino-5-chlorobenzophenone (2A5CB) were grown by Microtube Czochral- ski method using Microtube as a seed. The grown crystals were characterized by single crystal and powder X-ray diffraction. The functional groups of the grown crystal were found using Fourier transform ...

  5. Growth of 2-amino-5-chlorobenzophenone single crystal by ...

    Indian Academy of Sciences (India)

    Organic single crystals of 2-amino-5-chlorobenzophenone (2A5CB) were grown by Microtube Czochralski method using Microtube as a seed. The grown crystals were characterized by single crystal and powder X-ray diffraction. The functional groups of the grown crystal were found using Fourier transform infrared ...

  6. Particle-based simulations of powder coating in additive manufacturing suggest increase in powder bed roughness with coating speed

    OpenAIRE

    Parteli Eric J. R.; Pöschel Thorsten

    2017-01-01

    We have developed the first particle-based numerical tool to simulate the coating of powder particles in additive manufacturing devices. Our Discrete Element Method considers realistic particle shapes and incorporates attractive interaction (van-der-Waals) forces between the particles. From simulations of powder coating using a roller as coating device, we find that the surface roughness of the powder bed scales with the square of coating speed. Moreover, we find that using fine, highly polyd...

  7. FORMATION MECHANISM OF NANOSIZED TIN OXIDE (SnO2 POWDER DURING HYDROTHERMAL SYNTHESIS

    Directory of Open Access Journals (Sweden)

    M. Ozan ÖZER

    2011-06-01

    Full Text Available Preparation of nanosized SnO₂ electroceramic powders via hydrothermal synthesis was investigated as a function of initial concentration and treatment time in order to understand the formation and growth mechanisms. SnO₂ powder was successfully synthesized from the hydrous tin oxide by hydro- thermal synthesis at 200°C. Crystalline SnO₂ particles with a specific surface area as high as 170 m₂/g were produced in a single step without requiring any calcination process. As initial concentration of metal cation increases from 0.0125 to 0.05 M, an Ostwald ripening type growth process was observed in the crystallite size from 3.1 to 4.6 nm. Evolution of tin oxide particles was also investigated by al- tering the treatment time from 1 to 24 h and a diffusion controlled growth behavior was observed as a function of synthesis time.

  8. Comprehensive characterization of BiFeO3 powder synthesized by the hydrothermal procedure

    Directory of Open Access Journals (Sweden)

    Maria Čebela

    2016-12-01

    Full Text Available In this paper, bismuth ferrite (BFO particles synthesized by controlled hydrothermal process, where the particles of small sizes and with high purity were obtained. Structural analysis showed that non-annealed powder can be perfectly fitted to rhombohedral space group R3c and contains a very small amount of secondary phase, whereas the final product (annealed at 800 °C represents single-phase perovskite powder with high crystallinity. HRTEM analysis confirmed existence of twin stacking faults, which are responsible for enhanced magnetic properties. EPR measurements suggested existence of electrons trapped by vacancies or defects. It has been proposed that existence of Fe3+−OV defect complex could be generated at elevated temperatures followed by formation of trivalent Fe ions, which intensely provide local 3d moments.

  9. Manganese iron oxide superparamagnetic powder by mechanochemical processing. Nanoparticles functionalization and dispersion in a nanofluid

    Energy Technology Data Exchange (ETDEWEB)

    Bellusci, M., E-mail: mariangela.bellusci@enea.it; Aliotta, C. [ENEA, CR Casaccia, Dipartimento di Chimica e Technologia dei Materiali (Italy); Fiorani, D. [ISM-CNR, Area della Ricerca (Italy); La Barbera, A.; Padella, F. [ENEA, CR Casaccia, Dipartimento di Chimica e Technologia dei Materiali (Italy); Peddis, D. [ISM-CNR, Area della Ricerca (Italy); Pilloni, M. [ENEA, CR Casaccia, Dipartimento di Chimica e Technologia dei Materiali (Italy); Secci, D. [Universita di Roma La Sapienza, Dipartimento di Chimica e Tecnologie del Farmaco (Italy)

    2012-06-15

    Manganese ferrite nanoparticles were synthesized using a High-Energy Ball-Milling mechanochemical method. After 1 h of milling, the process produces a material consisting of single crystalline domain nanoparticles having a diameter of about 8 nm. Chemical properties of the synthesized powders allow an easy functionalization with citric acid. Both as-obtained and functionalized samples show superparamagnetic behaviour at room temperature, and the functionalized powder is stably dispersible in aqueous media at physiological pH. The average hydrodynamic diameter is equal to {approx}60 nm. Nanoparticles obtained by the reported High-Energy Ball-Milling method can be synthesized with high yield and low costs and can be successfully utilized in ferrofluids development for biomedical applications.

  10. Effect of target-fixture geometry on shock-wave compacted copper powders

    Science.gov (United States)

    Kim, Wooyeol; Ahn, Dong-Hyun; Yoon, Jae Ik; Park, Lee Ju; Kim, Hyoung Seop

    2018-01-01

    In shock compaction with a single gas gun system, a target fixture is used to safely recover a powder compact processed by shock-wave dynamic impact. However, no standard fixture geometry exists, and its effect on the processed compact is not well studied. In this study, two types of fixture are used for the dynamic compaction of hydrogen-reduced copper powders, and the mechanical properties and microstructures are investigated using the Vickers microhardness test and electron backscatter diffraction, respectively. With the assistance of finite element method simulations, we analyze several shock parameters that are experimentally hard to control. The results of the simulations indicate that the target geometry clearly affects the characteristics of incident and reflected shock waves. The hardness distribution and the microstructure of the compacts also show their dependence on the geometry. With the results of the simulations and the experiment, it is concluded that the target geometry affects the shock wave propagation and wave interaction in the specimen.

  11. An empirical-statistical model for laser cladding of WC-12Co powder on AISI 321 stainless steel

    Science.gov (United States)

    Erfanmanesh, Mohammad; Abdollah-Pour, Hassan; Mohammadian-Semnani, Hamidreza; Shoja-Razavi, Reza

    2017-12-01

    In this study, laser cladding of WC-12Co powder on AISI 321 steel substrate was optimized using an empirical-statistical viewpoint. The correlations that exist between key parameters of the process (i.e., laser power, scanning speed, powder feeding rate) and geometrical characteristics for single clads (i.e. height, width, dilution, and wetting angle) were predicted and analyzed by regression method (RA). The preliminary geometrical considerations allowed to choose the processing parameters which led to high quality clads with minimum porosity. All considerations finally resulted in the development of a processing map that shows the optimum parameters for laser cladding process of WC-12Co powder on AISI 321 stainless steel.

  12. International outbreak of multiple Salmonella serotype infections linked to sprouted chia seed powder - USA and Canada, 2013-2014.

    Science.gov (United States)

    Harvey, R R; Heiman Marshall, K E; Burnworth, L; Hamel, M; Tataryn, J; Cutler, J; Meghnath, K; Wellman, A; Irvin, K; Isaac, L; Chau, K; Locas, A; Kohl, J; Huth, P A; Nicholas, D; Traphagen, E; Soto, K; Mank, L; Holmes-Talbot, K; Needham, M; Barnes, A; Adcock, B; Honish, L; Chui, L; Taylor, M; Gaulin, C; Bekal, S; Warshawsky, B; Hobbs, L; Tschetter, L R; Surin, A; Lance, S; Wise, M E; Williams, I; Gieraltowski, L

    2017-06-01

    Salmonella is a leading cause of bacterial foodborne illness. We report the collaborative investigative efforts of US and Canadian public health officials during the 2013-2014 international outbreak of multiple Salmonella serotype infections linked to sprouted chia seed powder. The investigation included open-ended interviews of ill persons, traceback, product testing, facility inspections, and trace forward. Ninety-four persons infected with outbreak strains from 16 states and four provinces were identified; 21% were hospitalized and none died. Fifty-four (96%) of 56 persons who consumed chia seed powder, reported 13 different brands that traced back to a single Canadian firm, distributed by four US and eight Canadian companies. Laboratory testing yielded outbreak strains from leftover and intact product. Contaminated product was recalled. Although chia seed powder is a novel outbreak vehicle, sprouted seeds are recognized as an important cause of foodborne illness; firms should follow available guidance to reduce the risk of bacterial contamination during sprouting.

  13. Mixture of fuels for solution combustion synthesis of porous Fe{sub 3}O{sub 4} powders

    Energy Technology Data Exchange (ETDEWEB)

    Parnianfar, H.; Masoudpanah, S.M., E-mail: masoodpanah@iust.ac.ir; Alamolhoda, S.; Fathi, H.

    2017-06-15

    Highlights: • Mixture of glycine and urea fuels was applied for solution combustion synthesis of Fe3O4 powders. • The phase and crystallite size of the as-combusted powders depends on the fuel to oxidant ratio (ϕ). • The maximum density (0.033 cm{sup 3}/g) was observed for the as-combusted powders at ϕ = 1. • The highest Ms of 75.5 emu/g and the lowest Hc of 84 Oe were achieved at ϕ = 1. - Abstract: The solution combustion synthesis of porous magnetite (Fe{sub 3}O{sub 4}) powders by a mixture of glycine and urea fuels was investigated concerning the thermodynamic aspects and powder characteristics. The adiabatic combustion temperature and combusted species were thermodynamically calculated as a function of the fuel to oxidant molar ratio (ϕ). The combustion behavior, phase evolution, porous structure and magnetic properties were characterized by thermal analysis, X-ray diffractometry, N{sub 2} adsorption–desorption, electron microscopy and vibrating sample magnetometry techniques. Nearly single phase Fe{sub 3}O{sub 4} powders were synthesized by the mixture of fuels at ϕ values of 0.75 and 1. The as-combusted Fe{sub 3}O{sub 4} powders at ϕ = 1 exhibited porous structure with the specific surface area of 83.4 m{sup 2}/g. The highest saturation magnetization of 75.5 emu/g and the lowest coercivity of 84 Oe were achieved at ϕ = 1, due to the high purity and large crystallite size, inducing from the highest adiabatic combustion temperature.

  14. Importance of powder residence time for the aerosol delivery performance of a commercial dry powder inhaler Aerolizer(®).

    Science.gov (United States)

    Jiang, Liqun; Tang, Yue; Zhang, Hongjiu; Lu, Xifeng; Chen, Xijing; Zhu, Jiabi

    2012-10-01

    The performance of dry powder aerosol delivery systems depends not only on the powder formulation but also on the dry powder inhalers (DPIs). Effects of turbulence, grid, mouthpiece, inlet size, air flow, and capsule on the DPIs performance have been investigated previously. Considering powder dispersion in DPIs is a time-dependent process, the powder residence time in DPIs is supposed to have a great impact on DPIs efficiency. This study sought to investigate the effect of powder residence time on the performance of a commercial DPI Aerolizer(®). A standard Aerolizer(®) (SD) and five modified devices (MD1, MD2, MD3, MD4, and MD5) were employed for this research. Computational fluid dynamics analysis was used to calculate the flow field and the powder residence time in these devices. Recombinant human interleukin-2 inhalation powders and a twin impinger were used for the deposition experiment. The powder mean residence time in the secondary atomization zone of the devices was increased from 0 ms for SD to 0.33, 0.96, 1.42, 1.76, and 2.14 ms for MD1, MD2, MD3, MD4, and MD5, respectively. At a flow rate of 60 L/min, with an increase in the powder residence time in these devices, a significant gradual and increasing trend in the powder respirable fraction was observed from 29.1%± 1.1% (MD1) to 32.6% ± 2.2% (MD2), 37.1% ± 1.1% (MD3), and 43.7% ± 2.1% (MD4). There was no significant difference in the powder respirable fraction between SD and MD1 or between MD4 and MD5. Within a certain range, increasing the powder residence time could improve the performance of Aerolizer(®) by increasing the powder-air interaction time (the main reason) and increasing the powder-device compaction (the secondary reason). Combination of high turbulence level and sufficient powder residence time could further improve the device performance.

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

    OpenAIRE

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

    2015-01-01

    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...

  16. Complications associated with bacitracin powder in surgical wounds.

    Science.gov (United States)

    Beckman, Joshua M; Amankwah, Ernest K; Tetreault, Lisa L; Perlman, Sharon A; Tuite, Gerald F

    2015-12-01

    There has been renewed interest in the application of concentrated antibiotic powder to surgical wounds as a method to decrease infection rates. While there is substantial medical literature describing the effectiveness and complications associated with vancomycin and gentamycin powders, very little has been reported regarding the safety and effectiveness of bacitracin powder in surgical wounds. In this paper the authors report their detailed analysis of potential bacitracin powder-related complications in a population of pediatric patients who underwent shunt surgery. A detailed retrospective analysis was completed of all CSF shunt surgeries performed by the corresponding author at a large children's hospital between 2001 and 2013. This cohort consisted of many patients who were the subject of a previous report that showed the use of bacitracin powder in shunt wounds potentially decreased infection rates. Data were collected regarding the most common known complications of bacitracin, i.e., anaphylaxis, wound healing difficulties, and renal dysfunction. Data were stratified by typical demographic, medical, and surgical variables, including whether bacitracin powder was applied to wounds prior to closure. A total of 597 patients were reviewed in the analysis: 389 underwent surgery without bacitracin powder and 208 had concentrated bacitracin powder applied to the wounds prior to closure. The application of bacitracin powder was not associated with anaphylaxis (n = 0 both groups) or with an increase in wound breakdown (n = 5 in the control group, n = 0 in the bacitracin powder group) or renal dysfunction (creatinine/estimated glomerular filtration rate) using both comparative and multivariate analyses between the 2 groups. The sample size evaluating renal function was significantly lower (range 6-320) than that of anaphylaxis and wound breakdown analysis because only clinical values acquired during the routine care of these patients were available for analysis. The

  17. Sintering and composition of a powder mixture of fine Al2O3 and beta-sialon composite made from bauxite

    Directory of Open Access Journals (Sweden)

    Nan L.I.

    2002-01-01

    Full Text Available The sintering and composition of samples made of powder mixtures consisting of fine a-AI2O3 powder and beta-Sialon composite powder which was made from bauxite by carbonthermal reduction and nitridation were studied. The proportion of fine a-AI2O3 to beta'-Sialon composite powder in the powder mixture and soaking time give influences on porosity and relative density of the samples sintered at 1600eC. AI2O3, 15R and MgO which was added in 2 wt.% to improve sintering of the sample disappeared in the samples made of single P'-Sialon composite powder. They solubilize into beta-Sialon. In the sample made of a powder mixture consiting of 60 wt.% beta'-Sialon composite to 40 wt.% a-AI2O3 with addition of 2 wt.% MgO, beta'-Sialon, ct-AI2O3 and MgAION coexist after sintering at 1600BC.

  18. Characterization of La1-xSrxMnO3±d (x = 0.15, d 0) and La1-xSrxCrO3±d (x = 0.2, d 0) Powders by X-ray Powder Diffraction

    DEFF Research Database (Denmark)

    Berg, Rolf; Andersen, Mette M.; Bjerrum, Niels

    1996-01-01

    C, resulting in homogeneous single phased ceramic powders. X-ray diffraction diagrams were taken using copper Ka radiation with a Bragg-Brentano diffractometer. The obtained X-ray diagrams of the synthesised La0.85Sr0.15MnO3±d and La0.8Sr0.2CrO3±d (d 0) powders were compared to data in the literature which...

  19. X-Ray Powder Diffraction Study of Synthetic Palmierite, K{sub 2}Pb(SO{sub 4}){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    TISSOT JR.,RALPH G.; RODRIGUEZ,MARK A.; SIPOLA,DIANA L.; VOIGT,JAMES A.

    2000-12-19

    Palmierite (K{sub 2}Pb(SO{sub 4}){sub 2}) has been prepared via a chemical synthesis method. Intensity differences were observed when X-ray powder data from the newly synthesized compound were compared to the published powder diffraction card (PDF) 29-1015 for Palmierite. Investigation of these differences indicated the possibility of preferred orientation and/or chemical inhomogeneity affecting intensities, particularly those of the basal (00{ell}) reflections. Annealing of the Palmierite was found to reduce the effects of preferred orientation. Electron microprobe analysis confirmed K:Pb:S as 2:1:2 for the annealed Palmierite powder. Subsequent least-squares refinement and Rietveld analysis of the annealed powder showed peak intensities very close to that of a calculated Palmierite pattern (based on single crystal data), yet substantially higher than many of the PDF 29-1015 published intensities. Further investigation of peak intensity variation via calculated patterns suggested that the intensity discrepancies between the annealed sample and those found in PDF 29-1015 were potentially due to chemical variation in the K{sub 2}Pb(SO{sub 4}){sub 2} composition. X-ray powder diffraction and crystal data for Palmierite are reported for the annealed sample. Palmierite is Trigonal/Hexagonal with unit cell parameters a = 5.497(1){angstrom}, c = 20.864(2) {angstrom}, space group R-3m (166), and Z = 3.

  20. Pulsed Neutron Powder Diffraction for Materials Science

    Science.gov (United States)

    Kamiyama, T.

    2008-03-01

    The accelerator-based neutron diffraction began in the end of 60's at Tohoku University which was succeeded by the four spallation neutron facilities with proton accelerators at the High Energy Accelerator Research Organization (Japan), Argonne National Laboratory and Los Alamos Laboratory (USA), and Rutherford Appleton Laboratory (UK). Since then, the next generation source has been pursued for 20 years, and 1MW-class spallation neutron sources will be appeared in about three years at the three parts of the world: Japan, UK and USA. The joint proton accelerator project (J-PARC), a collaborative project between KEK and JAEA, is one of them. The aim of the talk is to describe about J-PARC and the neutron diffractometers being installed at the materials and life science facility of J-PARC. The materials and life science facility of J-PARC has 23 neutron beam ports and will start delivering the first neutron beam of 25 Hz from 2008 May. Until now, more than 20 proposals have been reviewed by the review committee, and accepted proposal groups have started to get fund. Those proposals include five polycrystalline diffractometers: a super high resolution powder diffractometer (SHRPD), a 0.2%-resolution powder diffractometer of Ibaraki prefecture (IPD), an engineering diffractometers (Takumi), a high intensity S(Q) diffractometer (VSD), and a high-pressure dedicated diffractometer. SHRPD, Takumi and IPD are being designed and constructed by the joint team of KEK, JAEA and Ibaraki University, whose member are originally from the KEK powder group. These three instruments are expected to start in 2008. VSD is a super high intensity diffractometer with the highest resolution of Δd/d = 0.3%. VSD can measure rapid time-dependent phenomena of crystalline materials as well as glass, liquid and amorphous materials. The pair distribution function will be routinely obtained by the Fourier transiformation of S(Q) data. Q range of VSD will be as wide as 0.01 Å-1science and

  1. Adsorption of arsenate on untreated dolomite powder.

    Science.gov (United States)

    Ayoub, G M; Mehawej, M

    2007-09-05

    Raw dolomite powder was evaluated for its efficiency in adsorbing As(V) from water. An experimental setup comprised of a fluidized dolomite powder bed was used to assess the impact of various test variables on the efficiency of removal of As(V). Test influents including distilled water (DW), synthetic groundwater (SGW) and filtered sewage effluent (FSE) were employed to assess the effect of influent parameters on the adsorption process and the quality of the effluent generated. Dolomite exhibited good As(V) removal levels for distilled water (>92%) and synthetic ground water (>84%) influents at all initial As(V) concentrations tested (0.055-0.600 ppm). Breakthrough of dolomite bed occurred after 45 bed volumes for DW and 20 bed volumes for SGW influents with complete breakthrough taking place at more than 300 bed volumes. As(V) removal from FSE influents was relatively unsuccessful as compared to the DW and SGW influents. Partial removal in the order of 32% from filtered sewage effluent at initial concentration of 0.6 mg/L started at 75 bed volumes and gradually stopped at 165 bed volumes. Varying degrees of As(V) adsorption capacities were observed by the different test influents employed, which indicate that the adsorption of As(V) is adversely affected by competing species, mainly sulfates and phosphates present in the influent. The adsorptive behavior of dolomite was described by fitting data generated from the study into the Langmuir and Freundlich isotherm models. Both models described well the adsorption of dolomite. The average isotherm adsorptive capacity was determined at 5.02 mug/g. Regeneration of the dolomite bed can be achieved with the use of caustic soda solution at a pH of 10.5.

  2. Erosion dynamics of powder snow avalanches - Observations

    Science.gov (United States)

    Sovilla, Betty; Louge, Michel

    2013-04-01

    Powder snow avalanches (PSA) entrain massive amounts of material from the underlying snow cover by erosion mechanisms that are not fully understood. Despite their inherent diversity, PSAs have recognizable flow features: they are fast, reaching velocity up to 80 m/s, they develop a tall, low density powder cloud and, at the same time, they can exert impact pressure with similar magnitudes of high density flow. In this talk, we report observations that underscore the interplay between entrainment and flow dynamics qualitatively shared by several PSAs at the Vallée de la Sionne test site in Switzerland. Measurements include time-histories of snow pack thickness with buried FMCW radar and time-histories of particle velocity using optical sensors, cloud density and cluster size using capacitance probes, and impact pressure measured at several elevations on a pylon. Measurements show that, at the avalanche front, a layer of light, cold and cohesionless snow is rapidly entrained, creating a turbulent and stratified head region with intermittent snow clusters. Fast and localized entrainment of deeper and warmer snow layers may also occur well behind the front, up to a distance of hundreds of meters, where pronounced stratification appears and snow clusters grow larger. In the avalanche head, impact pressure strongly fluctuates and is larger near the ground. Velocity profiles change throughout the avalanche head, with more abrupt changes localized where rapid entrainment occurs. A basal, continuous dense layer forms as deeper, warmer and denser snow cover is entrained and as suspended material starts to deposit. The thickness of the basal layer progressively increases toward the avalanche tail where, finally, deposition occurs en masse. Toward the avalanche tail, velocity profiles tend to become uniform, impact pressures are lower and nearly constant, while entrainment processes are negligible. These observations underscore the relevance of entrainment location and the

  3. Plasma spheroidization of nickel powders in a plasma reactor

    Indian Academy of Sciences (India)

    Unknown

    factors to be considered in order to ensure high spray efficiency and better coating properties. For smooth and uniform feeding of powders into plasma jet, the powder particles have to be spherical in shape. High tem- peratures and steep temperatures present in thermal plasma is exploited to spheroidize particles in the pre-.

  4. Acceptability of chicken powder in home prepared complementary ...

    African Journals Online (AJOL)

    The chicken powder was incorporated into a breakfast meal (“Tom Brown”) and lunch/supper meal (rice and gravy) on weight basis according to predetermined proportions of the raw ingredients. Each meal consisted of a control sample (not containing chicken powder) and 3 test samples containing different amounts of ...

  5. Evaluation of the disintegrant and dissolution properties Of Powder ...

    African Journals Online (AJOL)

    Extracted cellulose and powder from cocoa pod husk were characterized physicochemical, their distingrant efficacy determined and compared with standard disintegrants such as maize starch and micro crystalliro cellulose. To evaluate the disintegrant and dissolution efficacy of extracted cellulose and powder from cocoa ...

  6. Prediction of the Effective Thermal Conductivity of Powder Insulation

    Science.gov (United States)

    Jin, Lingxue; Park, Jiho; Lee, Cheonkyu; Jeong, Sangkwon

    The powder insulation method is widely used in structural and cryogenic systems such as transportation and storage tanks of cryogenic fluids. The powder insulation layer is constructed by small particle powder with light weight and some residual gas with high porosity. So far, many experiments have been carried out to test the thermal performance of various kinds of powder, including expanded perlite, glass microspheres, expanded polystyrene (EPS). However, it is still difficult to predict the thermal performance of powder insulation by calculation due to the complicated geometries, including various particle shapes, wide powder diameter distribution, and various pore sizes. In this paper, the effective thermal conductivity of powder insulation has been predicted based on an effective thermal conductivity calculationmodel of porous packed beds. The calculation methodology was applied to the insulation system with expanded perlite, glass microspheres and EPS beads at cryogenic temperature and various vacuum pressures. The calculation results were compared with previous experimental data. Moreover, additional tests were carried out at cryogenic temperature in this research. The fitting equations of the deformation factor of the area-contact model are presented for various powders. The calculation results show agood agreement with the experimental results.

  7. Effect of particle properties on the flowability of ibuprofen powders.

    Science.gov (United States)

    Liu, L X; Marziano, I; Bentham, A C; Litster, J D; White, E T; Howes, T

    2008-10-01

    Powder flowability is one of the key parameters in the pharmaceutical tabletting process. The flowability is affected by both the particles' properties and the tabletting equipment characteristics. Although it is generally accepted that powder flowability increases with an increase in particle size, quantitative studies and comprehensive theoretical insights into the particle property effects are still lacking. In this paper, ibuprofen, a non-steroidal drug widely used as an anti-inflammatory analgesic was chosen as a model material to assess the effect of particle properties on its flowability. Ibuprofen typically has a needle shaped morphology. The flowability of ibuprofen size fractions was studied in detail using two flow measurement methods. The separated fractions were also compared to magnesium stearate lubricated ibuprofen and its size fractions. The experimental results showed that powder flowability is significantly affected by both the particle size and size distribution. The finest size fraction that is separated from the bulk ibuprofen powder flows better than the bulk powder. For powders with narrow size distributions, the flowability increases significantly with the increase in particle size. In addition, admixing magnesium stearate to ibuprofen not only increases the flow function of the powder, but also reduces the internal friction angle. A theoretical analysis based on the limiting tensile strength of the powder bed was carried out and the flow conditions for particles of different size and shape were developed.

  8. 21 CFR 520.763b - Dithiazanine iodide powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dithiazanine iodide powder. 520.763b Section 520.763b Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... of use. (1) Dithiazanine iodide powder is administered to dogs by mixing the proper dosage in the dog...

  9. The formulation and evaluation of salbutamol dry powder inhalation ...

    African Journals Online (AJOL)

    Metered dose inhalers (MDIs) contain chlorofluorocarbons, widely known, to affect the environment adversely. These chemicals deplete the ozone layer. The use of dry powder inhalers is therefore in the ascendance to replace MDIs for delivery of medicines to the respiratory tract. In this study we have formulated dry powder ...

  10. Powder Flow Testing: Judicious Choice of Test Methods.

    Science.gov (United States)

    Tay, Justin Yong Soon; Liew, Celine Valeria; Heng, Paul Wan Sia

    2017-07-01

    Flow property of pharmaceutical powders can be assessed by various flow testers and test methods. In this study, eight commercially available lactose grades were sourced and tested for angles of repose, tapping studies, shear cell measurements, stirred powder rheometry, and avalanching powder measurements. The relationships between various flow parameters and particle size were analyzed. Deviations from the general trend could be attributed to either the insensitivity of the test or differences in particle shape. The basic flowability energy of the powder rheometer was unable to reconcile the effects of shape and particle size on powder flowability. Avalanche time of the revolving drum powder analyzer and angle of repose exhibited good correlation with each other (r = 0.92) but experienced poor resolution for samples of smaller particle sizes due to powder cohesiveness and the propensity for agglomerative flow. Flow test parameters could be categorized into three broad types, based on their relationship with particle size: (i) linear relationship, (ii) test parameter more sensitive to smaller sized particles, and (iii) test parameter more sensitive to larger sized particles. Choice of test parameters used to represent powder flow should be dependent on the sensitivity of the selected flow test methods to the sample types.

  11. optimizing soybean flour., whey powder. and colostrum ratios for ...

    African Journals Online (AJOL)

    SUMMARY: The object of the study was to determine diet combinations consisting of soybean flour, whey powder and colostrum that can be em- ... of the liquid diets varied from l0 to 2A9;, the whey powder content from 40 to 609oand the colostrum content from 20 to 509e, on a dry mass ..... Although pancreatic iuice flow.

  12. Thermophysical characterization of the powder resulting from the ...

    African Journals Online (AJOL)

    This paper presents the results of thermophysical characterization of the powder resulting from the solar drying of Moringa oleifera leaves. The desorption isotherms of the powder, are determined by the gravimetric static method. The models of B.E.T, Smith, Henderson, Iglesias and GAB are used for the smoothing of the ...

  13. Effect of Tomato ( Lycopersicon esculentum ) powder on oxidative ...

    African Journals Online (AJOL)

    Antioxidant potency of graded levels of tomato powder in cooked and raw broiler meat under refrigerated storage was evaluated and compared with that of Butylated Hydroxyl Anisole (BHA), a synthetic antioxidant. To a separate 200g of minced broiler meat, 0% (control), 0.5%, 1% and 1.5% of tomato powder were applied.

  14. KINETICS OF DENSIFICATION PROCESSES OF POWDER MATERIALS UNDER ELECTROPULSE SINTERING

    NARCIS (Netherlands)

    Grigoryev, E. G.

    The process of electropulse sintering of ferrous and high-speed steel powder materials by powerful pulse current and external pressure was investigated. Formation of high density and high strength structure of ferrous and highspeed steel powder materials was analyzed and optimal process parameters

  15. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process,.

  16. Effect of annealing process of iron powder on magnetic properties ...

    Indian Academy of Sciences (India)

    Iron powder magnetic cores are used as soft magnetic rotors, in micro special motors such as BS brake motors, refrigerator compressor motors and brushless servo motors. Heat treatment of iron powder played an important role in the magnetic properties and loss of the motor cores. After the annealing process, the cracks ...

  17. Effects of coriander ( Coriandrum sativum L.) seed powder and ...

    African Journals Online (AJOL)

    Feed conversion ratios improved with the inclusion of coriander powder in the diet throughout the experimental period. These results suggest that coriander powder in the diet and coriander extract in water could replace synthetic antibiotics and could be regarded as natural feed additives and growth promoters in poultry ...

  18. 21 CFR 524.1005 - Furazolidone aerosol powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Furazolidone aerosol powder. 524.1005 Section 524.1005 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Furazolidone aerosol powder. (a) Specifications. The product contains either 4 or 10 percent furazolidone in...

  19. Toxicity and Histopathological Effects of Portland Cement Powder in ...

    African Journals Online (AJOL)

    The most common gill changes at all doses of Portland cement powder in solution were destruction of gill lamella, epithelial hyperplasia and epithelial hypertrophy. Hepatic lesions in the liver tissues of fish exposed to Portland cement powder in solution were characterized by degeneration of hepatocyte, vascuolization of ...

  20. Statistical Description of Segregation in a Powder Mixture

    DEFF Research Database (Denmark)

    Chapiro, Alexander; Stenby, Erling Halfdan

    1996-01-01

    In this paper we apply the statistical mechanics of powders to describe a segregated state in a mixture of grains of different sizes. Variation of the density of a packing with depth arising due to changes of particle configurations is studied. The statistical mechanics of powders is generalized...

  1. Characterization of combustion synthesized zirconia powder by UV ...

    Indian Academy of Sciences (India)

    Fine powders of zirconia were prepared by employing combustion method with varying fuel to precursor molar ratios. The zirconia powders contained more amount of monoclinic phase as the fuel content was increased. This aspect was studied using XRD, IR and UV-vis diffuse reflectance techniques. The surface acidbase ...

  2. Assessment of the toxic potentials of some plants powders on ...

    African Journals Online (AJOL)

    Dried leaves powders of Guirea senegalensis, Piliostigma reticulatum and dried fruit powder of Piper guineense, were tested along side a conventional insecticide, Actellic-2-Dust, to compare their efficacies on survival of cowpea weevil (Callosobuchus maculates) during storage. Both the treated and untreated cowpeas ...

  3. The effect of powder metallurgy process parameters on mechanical ...

    African Journals Online (AJOL)

    The ever-increasing development of applying the iron pieces made by powder metallurgy in car industries and other usages depends on making pieces with high density and consequently acceptable physical and mechanical properties. Regarding the effect of decrease in the powder bits' size on improvement of the ...

  4. Insecticidal activity of four medicinal plant powders and extracts ...

    African Journals Online (AJOL)

    Powders and extracts prepared from Capsicum frutescens, Cymbopogon citratus, Moringa oleifera, Anacardium occidentale were tested for their insecticidal potential against Angoumois grain moth, Sitotroga cerealella. The powder of C. frutescens had the highest mortality rate of 100% after 2 days of application at all tested ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-09-26

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

  6. Efficacy of two plant powders as cowpea grain protectants against ...

    African Journals Online (AJOL)

    Objective: This study was carried out to study insecticidal effect of powders from Chenopodium ambrosioides leaves and Aframomum melegueta seeds on cowpea weevil Callosobruchus maculatus. Methodology and Results: 5g of both powders of A. melegueta and C. ambrosioides were used in the proportions of C.

  7. Page 1 Ceramic oxide powders preparation—A novel chemical ...

    Indian Academy of Sciences (India)

    slow evaporation of the precursor solution to dry mass. The resultant powders obtained from thermolysis and flame pyrolysis both, may require further heat treatment for obtaining the desired crystalline phase. The exothermic decomposition of the precursor powder is accompanied by the evolution of large amounts of gases.

  8. Shock wave equation of state of powder material

    NARCIS (Netherlands)

    Dijken, D.K.; Hosson, J.Th.M. De

    1994-01-01

    A model is proposed to predict the following quantities for powder materials compacted by shock waves: the pressure, the specific volume, the internal energy behind the shock wave, and the shock-wave velocity U-s. They are calculated as a function of flyerplate velocity u(p) and initial powder

  9. Computation of X-ray powder diffractograms of cement components ...

    Indian Academy of Sciences (India)

    C and ground to fine powder using mortar and pestle. The paste samples analysed by QXRD technique were prepared by homogeneously mix- ing dried cement paste powder and rutile in the weight ratio of 5:1 and the corresponding diffractograms were recorded for quantitative measurement of the degree of hydration (α).

  10. Influence of oxidant and fuel on the powder characteristics of ...

    Indian Academy of Sciences (India)

    attention recently, the influence of oxidants and different fuels' sources on the synthesized powders has not yet been thoroughly studied. ... nitrate as an oxidant on the powder characteristics of LiNbO3 synthesized by combustion method. In addition .... C, and then crushed with a pestle in an agate mortar, sieved through a ...

  11. Can patients use all dry powder inhalers equally well?

    NARCIS (Netherlands)

    Gustafsson, P; Taylor, A; Zanen, P; Chrystyn, H

    2005-01-01

    If patients are unable to use their inhaler, drug delivery may be unsatisfactory and the patients may fail to benefit from the prescribed medication. It is important to consider whether patients can use all dry powder inhalers equally well. Changing a patient from a dry powder inhaler used well to

  12. 21 CFR 520.88d - Amoxicillin trihydrate soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Amoxicillin trihydrate soluble powder. 520.88d Section 520.88d Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... trihydrate soluble powder. (a) Specifications. Each gram contains amoxicillin trihydrate equivalent to 115.4...

  13. 21 CFR 520.90e - Ampicillin trihydrate soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ampicillin trihydrate soluble powder. 520.90e Section 520.90e Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... trihydrate soluble powder. (a) Specifications. Each gram contains ampicillin trihydrate equivalent to 88.2...

  14. 21 CFR 524.1580c - Nitrofurazone soluble powder.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Nitrofurazone soluble powder. 524.1580c Section... § 524.1580c Nitrofurazone soluble powder. (a) Specifications. The drug contains 0.2 percent nitrofurazone in a water-soluble base. (b) Sponsor. See Nos. 000010, 000069, and 050749 in § 510.600(c) of this...

  15. Rapid flow cytometry analysis of antimicrobial properties of nettle powder and cranberry powder

    Science.gov (United States)

    Hattuniemi, Maarit; Korhonen, Johanna; Jaakkola, Mari; Räty, Jarkko; Virtanen, Vesa

    2010-11-01

    Both nettle (Urtica dioica) and cranberry (Vaccinium oxycoccus) are widely known to have good influence on health. The aim of this study was to investigate antimicrobial properties of nettle powder and cranberry powder against Escherichia coli (E. coli) and monitor the growth of the bacteria by a rapid flow cytometry (FCM) method. For FCM measurements samples were stained with fluorescent dyes. The inhibitory effects of plant material on growth of E. coli were estimated by comparing the results of control sample (E. coli) to E. coli samples with plant material. FCM offers both a brilliant tool to investigate the kinetics of the growth of bacterium, since subsamples can be taken from the same liquid medium during the growing period and with fluorescent dyes a rapid method to investigate viability of the bacterium.

  16. [Comparative study on HPLC fingerprint of ordinary powder and ultrafine powder for Gardenia jasminoides f. longicarpa].

    Science.gov (United States)

    Ju, Ai-Hua; Zhou, Kai; Zhang, Jing; Cai, Li-Juan; Song, Ping-Ping

    2013-07-01

    To establish an HPLC fingerprint of Gardenia jasminoides f. longicarpa and compare the differences between its ordinary powder and ultrafine powder. The analysis was carried out on a Kromasil C18 (250 mm x 4.6 mm, 5 microm) column with gradient elution of acetonitrile-0.4% phosphoric acid at the flow rate of 1.0 ml/min. The wavelength was 240 nm during 0 - 40 min and 440 nm during 40 - 80 min. HPLC fingerprint of Gardenia jasminoides f. longicarpa was established, 23 common peaks were identified,and the similarity of 10 samples was greater than 0.9. Ultrafine grinding did not change the types and number of chemical compositions, but it obviously increased the content of main chemical compositions. The HPLC fingerprint is accurate, reliable and repeatable, which can be used for quality control of Gardenia jasminoides f. longicarpa. Ultrafine grinding can stimulate the release of chemical components of Gardenia jasminoides f. longicarpa.

  17. DREAM — a versatile powder diffractometer at the ESS

    Science.gov (United States)

    Schweika, W.; Violini, N.; Lieutenant, K.; Zendler, C.; Nekrassov, D.; Houben, A.; Jacobs, P.; Henry, P. F.

    2016-09-01

    The instrument DREAM, in construction at the long pulse European Spallation Source (ESS), is a new type of neutron time-of-flight powder diffractometer, which utilizes additional choppers to meet the typical high resolution requests. Pulses will be of symmetric shape and their width can be varied from 10 μs to 1 ms, providing an unprecedented flexibility from highest to low resolution with optimized intensities at the superior brightness of the 5 MW source. The design is driven particularly by the needs and challenges for small and complex samples, large unit cell materials, thermoelectric cage structures or metal-organic framework structures, multiphase battery materials and complex magnetic structures. Therefore, the chosen wavelength bandwidth of 3.7 Å may cover well the peak intensities of the thermal and cold moderator used simultaneously and provides a sufficient Q (and d) range for obtaining diffraction patterns in a single setting. VITESS simulations show a performance that is about two orders of magnitude higher than current best instruments.

  18. Minerals and Total Polyphenolic Content of Some Vegetal Powders

    Directory of Open Access Journals (Sweden)

    Roxana E. TUFEANU

    2017-11-01

    Full Text Available The total polyphenolic content and minerals were determined for chia seeds, Psyllium husks and watermelon rind powder. The minerals content was performed by using the Inductively Coupled Plasma Optical Emissions Spectrometer and Atomic Absorption Spectrometer, technique FIAS-Furnace (for Se. The sample with the highest content of polyphenols was chia (2.69 mg GAE/g s. followed by the watermelon rind powder. Reduced amounts of polyphenols were found in the Psyllium husks. Also, the total polyphenol concentration increased with the increase of the extraction time on the ultrasonic water bath. Minerals analysis indicated that powders obtained from chia seeds and watermelon rind contained large amounts of potassium, calcium, phosphorus and magnesium. The most abundant mineral in the Psyllium husks powder was found potassium, followed by calcium. In conclusion, these powders can be used as ingredients for functional food and food supplements production due to the high nutritional content and bioactive properties.

  19. Qualitative improvement of rabbit burgers using Zingiber officinale Roscoe powder

    Directory of Open Access Journals (Sweden)

    S. Mancini

    2017-12-01

    Full Text Available The object of this study was to evaluate the effect of Zingiber officinale powder on physical-chemical traits, microbiological growth and sensory properties of rabbit burger. Raw burgers (only meat and meat added with 1 and 2% w/w ginger powder were stored at 4°C for 1, 4 and 7 d and then cooked. Ginger modified the colour of both raw and cooked burgers, leading to more yellow hue and reducing lightness. Aspect of burgers were affected by ginger powder addition, leading to a noticeable difference between the samples. During storage time, the highest modifications were recorded for control samples, followed by burgers with added ginger. Sensory evaluation highlighted that ginger enhanced the juiciness of the burgers; moreover, burgers with ginger powder presented a significant delay in microbial growth. Ginger powder might be considered as a potential ingredient in rabbit meat products to increase their quality and extend their shelf-life.

  20. Influences of the Air in Metal Powder High Velocity Compaction

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2017-01-01

    Full Text Available During the process of metal powder high velocity impact compaction, the air is compressed sharply and portion remains in the compacts. In order to study the Influences, a discrete density volleyball accumulation model for aluminium powder was established with the use of ABAQUS. Study found that the powder porosity air obstruct the pressing process because remaining air reduced strength and density of the compacts in the current high-speed pressing (V≤100m/s. When speed further increased (V≥100m/s, the temperature of the air increased sharply, and was even much higher than the melting point of the material. When aluminium powder was compressed at a speed of 200m/s, temperatures of air could reach 2033 K, far higher than the melting point of 877 K. Increased density of powders was a result of local softening and even melt adhesive while air between particles with high temperature and pressure flowed past.

  1. Investigation of metal ions sorption of brown peat moss powder

    Science.gov (United States)

    Kelus, Nadezhda; Blokhina, Elena; Novikov, Dmitry; Novikova, Yaroslavna; Chuchalin, Vladimir

    2017-11-01

    For regularities research of sorptive extraction of heavy metal ions by cellulose and its derivates from aquatic solution of electrolytes it is necessary to find possible mechanism of sorption process and to choice a model describing this process. The present article investigates the regularities of aliovalent metals sorption on brown peat moss powder. The results show that sorption isotherm of Al3+ ions is described by Freundlich isotherm and sorption isotherms of Na+ i Ni2+ are described by Langmuir isotherm. To identify the mechanisms of brown peat moss powder sorption the IR-spectra of the initial brown peat moss powder samples and brown peat moss powder samples after Ni (II) sorption were studied. Metal ion binding mechanisms by brown peat moss powder points to ion exchange, physical adsorption, and complex formation with hydroxyl and carboxyl groups.

  2. Recovery Of Electrodic Powder From Spent Lithium Ion Batteries (LIBs

    Directory of Open Access Journals (Sweden)

    Shin S.M.

    2015-06-01

    Full Text Available This study was focused on recycling process newly proposed to recover electrodic powder enriched in cobalt (Co and lithium (Li from spent lithium ion battery. In addition, this new process was designed to prevent explosion of batteries during thermal treatment under inert atmosphere. Spent lithium ion batteries (LIBs were heated over the range of 300°C to 600°C for 2 hours and each component was completely separated inside reactor after experiment. Electrodic powder was successfully recovered from bulk components containing several pieces of metals through sieving operation. The electrodic powder obtained was examined by X-ray diffraction (XRD, energy dispersive X-ray spectroscopy (EDS, and atomic absorption spectroscopy (AA and furthermore image of the powder was taken by scanning electron microscopy (SEM. It was finally found that cobalt and lithium were mainly recovered to about 49 wt.% and 4 wt.% in electrodic powder, respectively.

  3. Powder Metallurgy Fabrication of Molybdenum Accelerator Target Disks

    Energy Technology Data Exchange (ETDEWEB)

    Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kiggans Jr., James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nunn, Stephen D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parten, Randy J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

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

  4. Advanced powder metallurgy aluminum alloys via rapid solidification technology

    Science.gov (United States)

    Ray, R.

    1984-01-01

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

  5. Powder injection molding of Stellite 6 powder: Sintering, microstructural and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Gülsoy, H. Özkan [Marmara University, Technology Faculty, Metall. and Mater. Eng., 34722 Istanbul (Turkey); Özgün, Özgür, E-mail: oozgun@bingol.edu.tr [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Bilketay, Sezer [Marmara University, Technology Faculty, Metall. and Mater. Eng., 34722 Istanbul (Turkey)

    2016-01-10

    The purpose of this study was to produce Co-based Stellite 6 superalloy components by using the method of Powder Injection Molding (PIM) and to characterize the microstructural and mechanical properties of the produced components. The experimental studies were started through the formation of feedstock by mixing Stellite 6 powder with a multicomponent binder system. Prepared feedstock was formed by utilizing powder injection molding technique. Then the molded samples were subjected to the solvent and thermal debinding processes. Different sintering cycles were applied to the raw components for the purpose of determining the optimum sintering conditions. The densities of the sintered components were determined in accordance with the Archimedes' principle. The microstructural characterization was performed through scanning electron microscope (SEM) analysis, energy dispersive spectrometry (EDS) analyses, and X-ray diffraction (XRD) analysis. Hardness measurement and tensile test were conducted in order to determine the mechanical properties. The results illustrated that the injection molded Stellite 6 components were composed of fine and equiaxed grains, plenty of carbide precipitates exhibiting homogenous distribution throughout the microstructure formed at the grain boundaries and thus the mechanical properties were considerably high.

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

    Science.gov (United States)

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

    2013-03-01

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

  7. A facile synthesis of ZnS nanocrystallites by pyrolysis of single ...

    Indian Academy of Sciences (India)

    )2 and ZnCl2 (cinnamtsczH)2 (cinnamtsczH = cinnamaldehyde thiosemicarbazone) as single source precursors. The prepared ZnS nanocrystallites were characterized by powder X-ray diffraction (XRD), transmission electron microscopy ...

  8. Development of a new method to get a reliable powder flow characteristics using only 1 to 2 g of powder.

    Science.gov (United States)

    Seppälä, Kari; Heinämäki, Jyrki; Hatara, Juha; Seppälä, Lassi; Yliruusi, Jouko

    2010-03-01

    In powder technology, it is often important to directly measure real powder flow rate from a small amount of powder. For example, in pharmaceutical industry, a frequent problem is to determine powder flow properties of new active pharmaceutical ingredient (API) in an early stage of the development when the amount of API is limited. The purpose of this paper is to introduce a new direct method to measure powder flow when the material is poorly flowing (cohesive) and the amount of material is about 1 to 2 g. The measuring system was simple, consisting of a flow chamber and electronic balance and an automated optical detection system, and for each measurement, only 1 to 2 g of sample was required. Based on the results obtained with this testing method, three selected sugar excipients, three grades of microcrystalline cellulose, and APIs (caffeine, carbamazepine, and paracetamol) can be classified as freely flowing, intermediate flowing, and poorly flowing powders, respectively. The average relative standard deviation for the flow time determinations was not more than 2-10%. The present novel flowability testing method provides a new tool for a rapid determination of flowing characteristics of powders (e.g., inhalation powders) and granules at a small scale.

  9. Magnetic properties of co-precipitated hexaferrite powders with Sm-Co substitutions optimized with the molten flux method

    Science.gov (United States)

    Serletis, C.; Litsardakis, G.; Pavlidou, E.; Efthimiadis, K. G.

    2017-11-01

    In this work, using the chemical coprecipitation method, Sr1-xSmxFe12-xCoxO19 (x = 0, 0.1, 0.2) hexaferrite powders were prepared. Major magnetization loops were recorded at room temperature in order to determine the correct calcination temperature for optimum hard magnetic properties. It is found that a small degree of substitution increases substantially the coercive field. Also, the use of the molten flux calcination method increases the remanent magnetization. SEM/EDXS and XRD measurements were performed at the calcined powders: the results show that a single hexaferrite phase is formed and that the substituted powders consist of an assembly of grains with a mean diameter of 40 nm. Measurements of minor magnetization loops and of the temperature and time dependence of the magnetization confirm that the powders consist of a non-oriented single domain magnetic particles assembly. The results indicate that Sm could be a viable replacement for La in the manufacturing of hexaferrites with a high-energy product.

  10. [Comparative analysis between origin of cooked traditional Chinese medicine powder and modern formula granules].

    Science.gov (United States)

    Li, Rui; Zhai, Hua-Qiang; Tian, Wei-Lan; Hou, Ji-Ru; Jin, Shi-Yuan; Wang, Yong-Yan

    2016-03-01

    In this study, the origin and causes of cooked traditional Chinese medicine powder were reviewed, and a comprehensive analysis was made for the time background of modern traditional Chinese medicine formula granules and the future development trend, in order to provide reference for application and promotion of traditional Chinese medicine formula granules. By reference to ancient medical books of previous dynasties, a system review was conducted for infancy, formation, maturity and transition of cooked traditional Chinese medicine powder, and a comprehensive analysis was made for the six factors of cooked traditional Chinese medicine powder's maturity in the Song Dynasty. Efforts were made to collect domestic and foreign research literatures of modern formula granules, understand the detailed development, and conduct an objective analysis of the current clinical application of modern formula granules. According to the comparative analysis for the application characteristics of cooked traditional Chinese medicine powder and modern formula granules, ①the popularity of cooked traditional Chinese medicine powder in the Song Dynasty has six factors: soaring numbers of medical students and medical practitioners, high medical expenses due to huge army, rapid population growth, frequent epidemics and increasing diseases, and insufficient finances of central and local governments. ②On the basis of clinical application characteristics of traditional Chinese medicine formula granules, traditional Chinese medicine formula granules contain extracted and concentrated effective components, which guarantee the curative effect, meet modern people's demands for "quick, simple and convenience" traditional Chinese medicine decoctions, show a relatively high cost performance; however, formula granules are restricted by their varieties and lack unified quality control standards, and single-extract formula granules have not synergy and attenuation effects of combined traditional

  11. Toward high performance in Powder Metallurgy

    Directory of Open Access Journals (Sweden)

    Torralba, José M.

    2014-06-01

    Full Text Available Powder Metallurgy (PM is technology well known for mass production of parts at low cost but usually with worse mechanical properties than same parts obtained by alternative routes. But using this technology, high performance materials can be obtained, depending of the processing route and the type and amount of porosity. In this paper, a brief review of the capabilities of powder technology is made with the objective of attaining the highest level of mechanical and physical properties. For this purpose, different strategies over the processing can be chosen: to act over the density/porosity level and properties of the pores, to act over strengthening mechanisms apart from the density of the material (the alloying system, the microstructure, the grain size,.., to improve the sintering activity by different routes and to use techniques that avoid the grain growth during sintering.La Pulvimetalurgia es una tecnología bien conocida por su faceta de producir piezas de forma masiva a bajo coste, pero habitualmente con una pérdida de propiedades mecánicas si se la compara con tecnologías alternativas para obtener las mismas piezas. Sin embargo, mediante esta tecnología, también se pueden obtener piezas de altas prestaciones, dependiendo de la ruta de procesado y del nivel de porosidad. En este trabajo, se realiza una sucinta revisión de las posibilidades de la tecnología de polvos que permitirían obtener los mayores niveles de prestaciones en cuanto a propiedades mecánicas y físicas. Se pueden elegir distintas estrategias en el procesado: actuar sobre el nivel de densidad/porosidad y las propiedades de los poros, actuar sobre mecanismos de endurecimiento distintos a la densidad (el sistema de aleación, la microestructura, el tamaño de grano,…, mejorar la activación durante la sinterización y utilizar técnicas que inhiban el tamaño de grano durante la sinterización.

  12. Homogeneous Precipitation of Nickel Hydroxide Powders

    Energy Technology Data Exchange (ETDEWEB)

    Mavis, Bora [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    Precipitation and characterization of nickel hydroxide powders were investigated. A comprehensive precipitation model incorporating the metal ion hydrolysis, complexation and precipitation reactions was developed for the production of the powders with urea precipitation method. Model predictions on Ni2+ precipitation rate were confirmed with precipitation experiments carried out at 90 C. Experimental data and model predictions were in remarkable agreement. Uncertainty in the solubility product data of nickel hydroxides was found to be the large contributor to the error. There were demonstrable compositional variations across the particle cross-sections and the growth mechanism was determined to be the aggregation of primary crystallites. This implied that there is a change in the intercalate chemistry of the primary crystallites with digestion time. Predicted changes in the concentrations of simple and complex ions in the solution support the proposed mechanism. The comprehensive set of hydrolysis reactions used in the model described above allows the investigation of other systems provided that accurate reaction constants are available. the fact that transition metal ions like Ni2+ form strong complexes with ammonia presents a challenge in the full recovery of the Ni2+. On the other hand, presence of Al3+ facilitates the complete precipitation of Ni2+ in about 3 hours of digestion. A challenge in their predictive modeling studies had been the fact that simultaneous incorporation of more than one metal ion necessitates a different approach than just using the equilibrium constants of hydrolysis, complexation and precipitation reactions. Another limitation of using equilibrium constants is that the nucleation stage of digestion, which is controlled mainly by kinetics, is not fully justified. A new program released by IBM Almaden Research Center (Chemical Kinetics Simulator™, Version 1.01) lets the user change

  13. Powder synthesis, processing and characterization of lanthanum silicates for SOFC application

    Energy Technology Data Exchange (ETDEWEB)

    Jothinathan, E.; Vanmeensel, K. [Department of Metallurgy and Materials Engineering, Kasteelpark Arenberg 44, B-3001 Heverlee, Leuven (Belgium); Vleugels, J., E-mail: jozef.vleugels@mtm.kuleuven.b [Department of Metallurgy and Materials Engineering, Kasteelpark Arenberg 44, B-3001 Heverlee, Leuven (Belgium); Van der Biest, O. [Department of Metallurgy and Materials Engineering, Kasteelpark Arenberg 44, B-3001 Heverlee, Leuven (Belgium)

    2010-04-16

    Recent studies have shown that rare earth silicates exhibit higher oxygen conductivity at lower temperatures (500-800 {sup o}C) compared to traditional yttria-stabilized cubic zirconia. Among the rare earth silicates, doped lanthanum silicates are known to exhibit higher ionic conductivity. The difficulty in sinterability of these powders combined with the fact that the electrolyte material should be sintered onto a porous anode material in a single sintering step to produce SOFC half cells requires very fine starting powders with high sinterability at lower temperatures (1000-1200 {sup o}C). In this paper, we report on the synthesis of lanthanum silicates doped with aluminium or iron using the sol-gel process. Using this fairly simple and quick process, nanometer sized powders with an average grain size below 100 nm have been synthesised, while the intrinsic nanostructure could be maintained in the fully densified electrolyte material after pulsed electric current sintering (PECS) at 1100-1200 {sup o}C.

  14. Evaluation of the imaging performance of LSO powder scintillator for use in X-ray mammography

    Science.gov (United States)

    Michail, C.; David, S.; Liaparinos, P.; Valais, I.; Nikolopoulos, D.; Kalivas, N.; Toutountzis, A.; Cavouras, D.; Kandarakis, I.; Panayiotakis, G.

    2007-09-01

    The aim of the present study was to evaluate the imaging performance of Lu 2SiO 5:Ce (LSO:Ce) powder scintillator for use in X-ray detectors used in mammography. LSO:Ce scintillator is a high efficiency, fast emitting material, which in single-crystal form is used in positron emission tomography detectors. A scintillating screen, with a coating thickness of 25 mg/cm 2, was prepared in our laboratory from commercially available LSO:Ce powder (Phosphor Technology Ltd.). The imaging performance of the screen was assessed by experimental determination of the modulation transfer function (MTF) and the noise transfer function (NTF). Experimental MTF values were compared to data obtained by a custom Monte Carlo simulation program. Screen irradiation was performed under exposure conditions employed in mammographic applications (27 kV p, 63 mA s). MTF was determined by the Square Wave Response Function (SWRF) method whereas NTF was estimated by Noise Power Spectrum (NPS) measurements, under uniform screen irradiation. Our results showed that LSO:Ce exhibits high MTF, which is comparable to that of the commercially used Gd 2O 2S:Tb powder scintillator. Considering our MTF results and the fast response of LSO:Ce scintillator screen (40 ns), this material can be considered for use in X-ray mammographic detectors.

  15. Production of spray-dried honey jackfruit (Artocarpus heterophyllus) powder from enzymatic liquefied puree.

    Science.gov (United States)

    Wong, Chen Wai; Tan, Hong Hock

    2017-02-01

    This paper presents the enzymatic liquefaction process for honey jackfruit optimized with Pectinex ® Ultra SP-L and Celluclast ® 1.5 L individually or in combinations at different concentrations (0-2.5% v/w) and incubation time (0-2.5 h). Treatment with combinations of enzymes showed a greater effect in the reduction of viscosity (83.9-98.8%) as compared to single enzyme treatment (64.8-87.3%). The best parameter for enzymatic liquefaction was obtained with 1.0% (v/w) Pectinex ® Ultra SP-L and 0.5% (v/w) Celluclast ® 1.5 L for 1.5 h. Spray drying process was carried out using different inlet temperatures (140-180 °C) and maltodextrin concentrations (10-30% w/w). Results indicated that the spray-dried honey jackfruit powder produced at 160 °C with 30% w/w maltodextrin gave the highest product yield (66.90%) with good powder qualities in terms of water activity, solubility, moisture content, hygroscopicity, color and bulk density. The spray-dried honey jackfruit powder could potentially be incorporated into various food products.

  16. Concurrent crack and powder cocaine users from Sao Paulo: Do they represent a different group?

    Directory of Open Access Journals (Sweden)

    Breen Gerome

    2006-01-01

    Full Text Available Abstract Background Cocaine abuse is a serious and socially damaging illegal drug problem. Different routes of administration are associated with a specific progression of use, different degrees of abuse liability, propensity for dependence and treatment response. There have been relatively few studies comparing different cocaine users groups and no studies into the characterization of the group of individuals reporting concurrent use of powder cocaine and crack cocaine. Methods Six hundred and ninety-nine cocaine users were assessed during the period August 1997 to October 1998 in one outpatient and six inpatient clinics located in the São Paulo, Brazil. Patients were interviewed using a structured questionnaire schedule in Portuguese, designed specifically for the Brazilian population. The statistical analyses were performed using either ANOVA or a chi-squared test and focusing on their preferred form of use/route of administration and other variables. Results For 83% of the variables tested in this study, the Dual Users subgroup (using both powder and crack cocaine demonstrated statistical differences from the single drug user subgroups. Those differences include the initiation of cocaine, the abuse of other illicit drugs, and rates of criminal history. Conclusion These data suggest cocaine-dependent individuals who report use of both powder and crack cocaine are an at least partially, distinct subgroup. However, further studies will be necessary to confirm this and to determine if they also show a different treatment response.

  17. Application of SnO2 Nano-powder on MEMS Type Gas Sensors

    Directory of Open Access Journals (Sweden)

    E. Abbaspour-Sani

    2007-04-01

    Full Text Available This paper describes a cost effective and new method for preparing SnO2 sol-gel as the basic material for the Micro-Electro-Mechanical System (MEMS type gas sensors. The SnO2 sol-gel was prepared by mixing SnCl4, propanol and isopropanol in a specified ratio. The produced sol-gel was exposed to two different decomposition temperatures of 600°C and 1200°C. Thermal treatment of the sol-gel resulted in formation of nano-crystalline single phase SnO2 powder having two different grain sizes. The grain size of the nano-powder calcinated at 600°C was about 10 nm and increased to about 80nm when the treatment temperature increased to 1200°C. The samples analyzed by XRD and TEM methods and both confirmed the grain size dependency on temperature. The prepared SnO2 sol-gels were applied on alumina substrates and the prepared samples were tested for sensitivity and selectivity using hydrogen, air and natural gas. The measurement results indicate a decrease in both selectivity and sensitivity of the gas sensor for increased nano-powder grain size.

  18. Primary packaging considerations in developing medicines for children: oral liquid and powder for constitution.

    Science.gov (United States)

    Campbell, Gossett A; Vallejo, Erick

    2015-01-01

    The packaging presentation of oral liquid pediatric medicines is a critical step in maintaining chemical and physical stability, compliance, adherence, and proper handling by the target patient population, guardians, caregivers, and health-care professionals. The common packaging presentations for commercial oral liquid pediatric drug products are glass bottle, plastic bottle, sachet, and stick pack configurations. The type of pack presentation selected is driven by the quality target product profile (QTPP) that is designed around the physicochemical properties of the drug substance and the desired drug product suitability for the target population. The QTPP defines the intended use of the drug product, drug product quality criteria, dose strength, dosage form, container closure system, storage conditions, stability criteria, dosing device, shelf life, and attributes affecting the pharmacokinetic characteristics. Oral liquid pediatric formulations are typically prepared from a powder that is constituted at the time of use as a suspension or a solution for single or multiple use depending on the stability of the constituted formulation. Active ingredients with high aqueous solubility can be developed as a powder for oral solution and presented in a bottle for multiple use product and a stick pack, packet, or sachet for single-use product. Active ingredients with low aqueous solubility can be developed as a powder for oral suspension and presented in a bottle for multiple use product and a stick pack or sachet for single-use product. A secondary package may be used in cases where the primary pack failed to provide adequate protection against light degradation. This work will help formulation scientists select the most appropriate pack presentation in the early stages of pediatric clinical development. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  19. Sinterability and microstructure evolution during sintering of ferrous powder mixtures

    Directory of Open Access Journals (Sweden)

    Kétner Bendo Demétrio

    2013-01-01

    Full Text Available The present work is focused on ferrous powder metallurgy and presents some results of a development of a suitable masteralloy for use as an additive to iron powder for the production of sintered steels. The masteralloy was produced by melting a powder mixture containing approximately Fe + 20% Ni + 20% Mn + 20% Si + 1% C (wt%, in order to obtain a cast billet that was converted into fine powder by crushing and milling. It was observed presence of SiC in the masteralloy after melting that is undesirable in the alloy. Si element should be introduced by using ferrosilicon. Sintered alloys with distinct contents of alloying elements were prepared by mixing the masteralloy powder to plain iron powder. Samples were produced by die compaction of the powder mixtures and sintering at 1200 °C in a differential dilatometer in order to record their linear dimensional behaviour during heating up and isothermal sintering, aiming at studying the sinterability of the compacts. Microstructure development during sintering was studied by SEM, XRD and microprobe analyses.

  20. Milk powders ageing: effect on physical and functional properties.

    Science.gov (United States)

    Thomas, Marie E C; Scher, Joël; Desobry-Banon, Sylvie; Desobry, Stéphane

    2004-01-01

    Milk powders are now considered as food ingredients, mainly because of the functional properties of milk proteins. During the storage of milk powders, many physicochemical damages, mainly dependent on lactose glass transition occur. They have important consequences on physical (flowability) and functional properties (solubility, emulsifying, and foaming properties) of milk powders. First, lactose crystallization modifies the microstructure and chemical composition of the surface of powder particles. Thus, milk powders flowability is decreased. Since the structure of milk proteins is destabilized, its solubility is damaged. Moreover, particle collapse and caking occur and mainly decrease the physical properties of milk powders (density and flowability). The mechanical stresses involved may also enhance proteins unfolding, which is detrimental to solubility. Finally, molecular mobility is favored upon ageing, and both chemical (Maillard reaction) and enzymatic reactions occur. Maillard reaction and oxidation enhance protein interactions and aggregations, which mainly lessen milk powders solubility. Maillard reaction also decreases emulsifying and foaming properties. Storage temperature and relative humidity have been considered as the predominant factors involved, but time, milk components, and their physical state also have been implied.

  1. Standard specification for nuclear-grade boron carbide powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This specification defines the chemical and physical requirements for boron carbide powder intended for a variety of nuclear applications. Because each application has a different need for impurity and boron requirements, three different chemical compositions of powder are specified. In using this specification, it is necessary to dictate which type of powder is intended to be used. In general, the intended applications for the various powder types are as follows: 1.1.1 Type 1—For use as particulate material in nuclear reactor core applications. 1.1.2 Type 2—Powder that will be further processed into a fabricated shape for use in a nuclear reactor core or used in non-core applications when the powder directly or indirectly may cause adverse effects on structural components, such as halide stress corrosion of stainless steel. 1.1.3 Type 3—Powder that will be used for non-core applications or special in-core applications. 1.2 The values stated in SI units are to be regarded as standard. No other ...

  2. Comparative evaluation of flow for pharmaceutical powders and granules.

    Science.gov (United States)

    Shah, Rakhi B; Tawakkul, Mobin A; Khan, Mansoor A

    2008-01-01

    The objective of the present work was to carry out a systematic evaluation of flow of pharmaceutical powders and granules using compendial and non-compendial methods. Angle of repose, bulk density, tapped density, Carr's compressibility index, and Hausner ratios were evaluated. Additionally, flow was characterized using a powder rheometer in which a sensitive force transducer monitors the forces generated as a result of the sample displacement. The critical attributes such as cohesivity index, caking strength, and flow stability were determined for samples. The samples consisted of different grades of magnesium stearate powder including bovine, vegetable, and food grade, physical mixture powder blend consisting of a model formulation, granules prepared by various methods including slugging, high shear granulator, and fluid bed dryer. Lubricant efficiency was also determined for granules lubricated with various concentrations of magnesium stearate. It was observed that the compendial methods were often non-discriminating for minor variations in powder flow. The additional characterization such as cohesivity, and caking strength were helpful in understanding the flow characteristics of pharmaceutical systems. The flow stability test determined that the powders were not affected by the test conditions on the rheometer. The non-compendial tests were discriminating to even minor variations in powder flow.

  3. Properties of magnetic nickel/porous-silicon composite powders

    Directory of Open Access Journals (Sweden)

    Toshihiro Nakamura

    2012-09-01

    Full Text Available The magnetic and photoluminescence (PL properties of nickel/porous-silicon (Ni/PSi composite powders are investigated. Ni/PSi composite powders are prepared by stain etching of Si powder in a HF/HNO3 solution followed by electroless plating of Ni nanoparticles on the stain-etched PSi powder in a NiCl2 solution. The Ni/PSi powders exhibit hydrophillicity, superparamagnetism caused by the deposited Ni nanoparticles, and orange-red PL owing to the nanostructured PSi surface. The degree of magnetization decreases with increasing Ni plating time, indicating its dependence on the size of the Ni nanoparticles. The Ni/PSi composite powders also show a stronger magnetization as compared to that of the Ni-particle-plated Si powder. The stronger magnetization results from the larger surface area of PSi. The PL intensity, peak wavelength, and lifetime of Ni/PSi are strongly dependent on the NiCl2 concentration. This dependence is due to the different thickness of the oxide overlayer on the PSi surface formed during the Ni plating process. The existence of the oxide overlayer also results in a small change in the PL intensity against excitation time.

  4. Device for preparing combinatorial libraries in powder metallurgy.

    Science.gov (United States)

    Yang, Shoufeng; Evans, Julian R G

    2004-01-01

    This paper describes a powder-metering, -mixing, and -dispensing mechanism that can be used as a method for producing large numbers of samples for metallurgical evaluation or electrical or mechanical testing from multicomponent metal and cermet powder systems. It is designed to make use of the same commercial powders that are used in powder metallurgy and, therefore, to produce samples that are faithful to the microstructure of finished products. The particle assemblies produced by the device could be consolidated by die pressing, isostatic pressing, laser sintering, or direct melting. The powder metering valve provides both on/off and flow rate control of dry powders in open capillaries using acoustic vibration. The valve is simple and involves no relative movement, avoiding seizure with fine powders. An orchestra of such valves can be arranged on a building platform to prepare multicomponent combinatorial libraries. As with many combinatorial devices, identification and evaluation of sources of mixing error as a function of sample size is mandatory. Such an analysis is presented.

  5. Characterization of Metal Powders Used for Additive Manufacturing

    Science.gov (United States)

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

    2014-01-01

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

  6. Cohesive, multicomponent, dense powder flow characterization by NIR.

    Science.gov (United States)

    Benedetti, C; Abatzoglou, N; Simard, J-S; McDermott, L; Léonard, G; Cartilier, L

    2007-05-24

    Non-aerated powder flows are frequently encountered in downstream pharmaceutical processes. Such flows occur at the entrance of powder compression units, and their characteristics are of great interest because any powder agglomeration or segregation can be detrimental to the quality of the final solid oral dosage form. This work was aimed at developing a process analytical technology (PAT) method, based on near-infrared spectroscopy (NIR) for the in-line powder flow characterization of pharmaceutical formulations. An Ibuprofen drug formulation was selected for study. A bench-scale hopper system was assembled to monitor powder flow behaviour. An in-line commercial NIR Axsun spectrometer and probe were chosen to collect in-line spectral data on dense, multicomponent, non-aerated powder flow prior to compression. Spectra were collected on flowing mannitol and pharmaceutical product blends. A specially designed, non-contact sampling interface allowed the collection of representative process powder flow spectra without affecting blend uniformity. A partial least squares chemometric model was developed for laboratory-prepared samples, to quantitatively determine the flowing powder's active pharmaceutical ingredient (API) level. Static sample spectra and flowing pure mannitol spectra proved to have a high degree of reproducibility. The model's standard error of calibration was 2.95% of the API level with a R2 of 0.991. Flowing blend powder spectra and API estimates showed variations consistent with those seen in model samples. The average values for flowing pharmaceutical blends were close to the API concentration, indicating that the proposed procedure was statistically acceptable. The model is considered very promising, and some improvements would lead to its final acceptance at production scale as a PAT tool.

  7. Characterization of Metal Powders Used for Additive Manufacturing.

    Science.gov (United States)

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

    2014-01-01

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

  8. Sensory analysis of cosmetic powders: personal care ingredients and emulsions.

    Science.gov (United States)

    Moussour, M; Lavarde, M; Pensé-Lhéritier, A-M; Bouton, F

    2017-02-01

    The powders are ingredients increasingly used in the formulation of cosmetic products for the sensory qualities they give. The objective of this study was the development of a lexicon and a referential for sensory characterization of these pure raw materials as well as formulations which contain them. Eleven expert panellists from Ecole de biologie industrielle de Cergy (France) developed a lexicon and a referential based on 12 powders of different chemical natures. The selected attributes were then used for performing a quantitative descriptive profile of two powders and an emulsion containing or not one of these two powders. A lexicon has been established through a consensus approach of the panel. It contains seven attributes that allow the evaluation of the powders in four phases: the appearance, the pickup, the application and the after-feel. This lexicon contains definitions and assessment protocols and provides references products. The quantitative descriptive profile of two powders of the same chemical nature, but different in physical quality showed significant differences in sensory level between products. These same attributes used to evaluate an emulsion containing the powder or not allowed to prove the contribution of these raw materials on the sensory specificities of the emulsion. The lexicon developed in this study can be used for assessment of other powders but also to define the quantities necessary to put in the formulation to meet the sensory characteristics of these raw materials powder. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  9. Antiviral activities of heated dolomite powder.

    Science.gov (United States)

    Motoike, Koichi; Hirano, Shozo; Yamana, Hideaki; Onda, Tetsuhiko; Maeda, Takayoshi; Ito, Toshihiro; Hayakawa, Motozo

    2008-12-01

    The effect of the heating conditions of dolomite powder on its antiviral activity was studied against the H5N3 avian influenza virus. Calcium oxide (CaO) and magnesium oxide (MgO), obtained by the thermal decomposition of dolomite above 800 degrees C, were shown to have strong antiviral activity, but the effect was lessened when the heating temperature exceeded 1400 degrees C. Simultaneous measurement of the crystallite size suggested that the weakening of the activity was due to the considerable grain growth of the oxides. It was found that the presence of Mg in dolomite contributed to the deterrence of grain growth of the oxides during the heating process. Although both CaO and MgO exhibited strong antiviral activity, CaO had the stronger activity but quickly hydrated in the presence of water. On the other hand, the hydration of MgO took place gradually under the same conditions. Separate measurements using MgO and Mg(OH)2 revealed that MgO had a higher antiviral effect than Mg(OH)2. From the overall experiments, it was suggested that the strong antiviral activity of dolomite was related to the hydration reaction of CaO.

  10. Tests on concrete containing cork powder admixtures

    Directory of Open Access Journals (Sweden)

    Guerra, I.

    2007-06-01

    Full Text Available The present study aimed to determine the physical and mechanical properties of laboratory concrete made with different proportions of cork powder. While the resulting material lacked the mechanical strength characteristic of concrete, its properties may prove to be apt for certain hardscaping and agricultural uses, such as in the manufacture of pavement for playgrounds and parks, or certain kinds of structures used in livestock raising. These findings need to be analyzed and verified.Este trabajo de investigación tiene por objeto conocer algunas propiedades físicas y mecánicas de un hormigón elaborado en laboratorio, adicionándole diversas proporciones de polvo de corcho. Las propiedades del material resultante, si bien carecen de la resistencia mecánica que caracteriza al hormigón, parecen interesantes para su uso en ciertas aplicaciones de la ingeniería agronómica tales como en la fabricación de piezas para solados de parques infantiles y jardines, o en los cubículos de ciertas construcciones ganaderas, extremos que es preciso analizar y comprobar.

  11. Substantiating powder metal life methodologies for engines

    Science.gov (United States)

    Domas, P. A.

    1993-04-01

    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) and damage tolerance (crack growth resistance) capability to insure reliability and safety. Fatigue life for these alloys can be influenced by inhomogeneities (inclusions) intrinsic to the microstructure as the result of processing, and by perturbations of the surface integrity during component manufacture and subsequent usage. Understanding of PM fatigue behavior and substantiation of life assessment methodology must appropriately recognize these potential influences. New testing, modeling, and analysis schemes are necessitated in engineering development programs addressing generation and validation of life prediction techniques for these materials. This paper outlines one approach to substantiating PM fatigue life prediction that attempts to recognize homogeneous fatigue initiation by incorporating probabilistic models and development testing methods that address material volume and component feature effects. Complications and limitations being addressed in ongoing work are discussed.

  12. The structure of powder snow avalanches

    Science.gov (United States)

    Sovilla, Betty; McElwaine, Jim N.; Louge, Michel Y.

    2015-01-01

    Powder snow avalanches (PSAs) can be hundreds of metres high and descend at astonishing speeds. This review paints a composite picture of PSAs from data acquired at the Vallée de la Sionne test site in Switzerland, including time-histories of snow cover thickness from buried RADAR and, at several elevations on a pylon, impact pressures from load cells, air pressure, particle velocity from optical sensors, and cloud density and particle cluster size from capacitance probes. PSAs feature distinct flow regions with stratification in mean density. At the head, highly fluctuating impact pressures weaken with elevation, while vertical velocity profiles evolve rapidly along the flow, suggesting that surface snow layers of light, cold, cohesionless snow erupt into a turbulent, inhomogeneous, recirculating frontal cloud region. For hundreds of metres behind the head, cloud stratification sharpens with the deposition of suspended cloud particles, while a denser basal flow of increasing thickness forms as deeper, warmer and heavier parts of the weakened snow cover are entrained. Toward the tail, vertical velocity profiles are more uniform, impact pressures become lower and steadier as the flow becomes thinner, and snow pack entrainment is negligible.

  13. Complex Impedance of Manganese Ferrite Powders Obtained by Two Different Methods

    Directory of Open Access Journals (Sweden)

    Mălăescu I.

    2015-12-01

    Full Text Available Two samples of manganese ferrite powder were obtained by the calcination method (sample A and hydrothermal method (sample B. The crystal structure of the samples has been determined using X-ray diffraction analysis (XRD. The results shown that the sample A has three phases (FeMnO3, Mn2O3 and Fe2O3 and the prevailing phase is FeMnO3 with perovskite structure and the sample B has only a single phase (MnFe2O4.

  14. Application of SnO2 Nano-powder on MEMS Type Gas Sensors

    OpenAIRE

    E. Abbaspour-Sani; M. N. Azarmanesh; M. Nasseri; Kh. Farhadi

    2007-01-01

    This paper describes a cost effective and new method for preparing SnO2 sol-gel as the basic material for the Micro-Electro-Mechanical System (MEMS) type gas sensors. The SnO2 sol-gel was prepared by mixing SnCl4, propanol and isopropanol in a specified ratio. The produced sol-gel was exposed to two different decomposition temperatures of 600°C and 1200°C. Thermal treatment of the sol-gel resulted in formation of nano-crystalline single phase SnO2 powder having two different grain sizes. The ...

  15. Corrosion issues of powder coated AA6060 aluminium profiles

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl

    2015-01-01

    In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

  16. A new process based agglomeration parameter to characterize ceramic powders

    Energy Technology Data Exchange (ETDEWEB)

    Balakrishna, Palanki [Nuclear Fuel Complex, 17-1-391/44 Subrahmanya Nagar, Saidabad, Hyderabad 500 059, Andhra Pradesh (India)], E-mail: bpalanki@rediffmail.com; Narasimha Murty, B.; Anuradha, M. [Nuclear Fuel Complex, 17-1-391/44 Subrahmanya Nagar, Saidabad, Hyderabad 500 059, Andhra Pradesh (India)

    2009-02-15

    Uranium dioxide powders are made through aqueous chemical route involving precipitation, drying, calcination and reduction. The presence of agglomerates causes powder packing difficulties in the compaction die, and non-uniform and incomplete densification on sintering. To quantify the degree of agglomeration, several authors have proposed 'Agglomeration Parameters'. The change in BET specific surface area of calcined U{sub 3}O{sub 8} upon reduction to UO{sub 2} per unit temperature difference is a simple new measure of agglomeration in uranium dioxide powders.

  17. Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

    Directory of Open Access Journals (Sweden)

    Apinpus Rujiwatra

    2011-01-01

    Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.

  18. Printed circuit board metal powder filters for low electron temperatures

    OpenAIRE

    Müller, F.; Mueller, Filipp; Schouten, Raymond N.; Brauns, M.; Gang, T.; Lim, Wee Han; Lai, Nai Shyan; Dzurak, Andrew S.; van der Wiel, Wilfred Gerard; Zwanenburg, Floris Arnoud

    2013-01-01

    We report the characterisation of printed circuit boards (PCB) metal powder filters and their influence on the effective electron temperature which is as low as 22 mK for a quantum dot in a silicon MOSFET structure in a dilution refrigerator. We investigate the attenuation behaviour (10 MHz–20 GHz) of filter made of four metal powders with a grain size below 50 μm. The room-temperature attenuation of a stainless steel powder filter is more than 80 dB at frequencies above 1.5 GHz. In all metal...

  19. Production of nanocrystalline metal powders via combustion reaction synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Frye, John G.; Weil, Kenneth Scott; Lavender, Curt A.; Kim, Jin Yong

    2017-10-31

    Nanocrystalline metal powders comprising tungsten, molybdenum, rhenium and/or niobium can be synthesized using a combustion reaction. Methods for synthesizing the nanocrystalline metal powders are characterized by forming a combustion synthesis solution by dissolving in water an oxidizer, a fuel, and a base-soluble, ammonium precursor of tungsten, molybdenum, rhenium, or niobium in amounts that yield a stoichiometric burn when combusted. The combustion synthesis solution is then heated to a temperature sufficient to substantially remove water and to initiate a self-sustaining combustion reaction. The resulting powder can be subsequently reduced to metal form by heating in a reducing gas environment.

  20. Shock wave equation of state of powder material

    Science.gov (United States)

    Dijken, D. K.; De Hosson, J. Th. M.

    1994-01-01

    A model is proposed to predict the following quantities for powder materials compacted by shock waves: the pressure, the specific volume, the internal energy behind the shock wave, and the shock-wave velocity Us. They are calculated as a function of flyerplate velocity up and initial powder specific volume V00. The model is tested on Cu, Al2024, and Fe. Calculated Us vs up curves agree well with experiments provided V00 is smaller than about two times the solid specific volume. The model can be used to predict shock-wave state points of powder or solid material with a lower or higher initial temperature than room temperature.

  1. Deformed liquid marbles: Freezing drop oscillations with powders

    KAUST Repository

    Marston, Jeremy

    2012-09-01

    In this work we show that when a liquid drop impacts onto a fine-grained hydrophobic powder, the final form of the drop can be very different from the spherical form with which it impacts. In all cases, the drop rebounds due to the hydrophobic nature of the powder. However, we find that above a critical impact speed, the drop undergoes a permanent deformation to a highly non-spherical shape with a near-complete coverage of powder, which then freezes the drop oscillations during rebound. © 2012 Elsevier B.V.

  2. Effect of thermal treatment on mechanically milled cobalt powder

    CSIR Research Space (South Africa)

    Bolokang, AS

    2012-03-01

    Full Text Available , there are studies reporting the metastable BCC crystal structure obtained in Co films [15, 16]. The stabilization of BCC Co depends on the crystalline size range of 2 to 5 nm [17]. In cemented carbides, Co is a suitable binder for HCP WC particles processed via... powder metallurgical route. In is the modern trend that nanocrystalline powders are used to improve the strength of cemented carbides [18-20]. Therefore, alloyed nanocrystalline carbide powders have been synthesized using MM technique [21, 22], while...

  3. Antioxidant effects of broccoli powder extract in goat meat nuggets.

    Science.gov (United States)

    Banerjee, Rituparna; Verma, Arun K; Das, Arun K; Rajkumar, V; Shewalkar, A A; Narkhede, H P

    2012-06-01

    The antioxidant potential of broccoli powder extract (BPE) was determined and evaluated in goat meat nuggets at three different levels 1, 1.5 and 2%, compared with control and butylated hydroxyl toluene (100ppm BHT). Total phenolics in 5mg broccoli powder was higher (Ppower of 10mg broccoli powder was comparable to the 100ppm BHT. Incorporation of 1.5 and 2% BPE decreased (Pgoat meat nuggets without affecting product acceptability. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Roller compaction: Effect of relative humidity of lactose powder.

    Science.gov (United States)

    Omar, Chalak S; Dhenge, Ranjit M; Palzer, Stefan; Hounslow, Michael J; Salman, Agba D

    2016-09-01

    The effect of storage at different relative humidity conditions, for various types of lactose, on roller compaction behaviour was investigated. Three types of lactose were used in this study: anhydrous lactose (SuperTab21AN), spray dried lactose (SuperTab11SD) and α-lactose monohydrate 200M. These powders differ in their amorphous contents, due to different manufacturing processes. The powders were stored in a climatic chamber at different relative humidity values ranging from 10% to 80% RH. It was found that the roller compaction behaviour and ribbon properties were different for powders conditioned to different relative humidities. The amount of fines produced, which is undesirable in roller compaction, was found to be different at different relative humidity. The minimum amount of fines produced was found to be for powders conditioned at 20-40% RH. The maximum amount of fines was produced for powders conditioned at 80% RH. This was attributed to the decrease in powder flowability, as indicated by the flow function coefficient ffc and the angle of repose. Particle Image Velocimetry (PIV) was also applied to determine the velocity of primary particles during ribbon production, and it was found that the velocity of the powder during the roller compaction decreased with powders stored at high RH. This resulted in less powder being present in the compaction zone at the edges of the rollers, which resulted in ribbons with a smaller overall width. The relative humidity for the storage of powders has shown to have minimal effect on the ribbon tensile strength at low RH conditions (10-20%). The lowest tensile strength of ribbons produced from lactose 200M and SD was for powders conditioned at 80% RH, whereas, ribbons produced from lactose 21AN at the same condition of 80% RH showed the highest tensile strength. The storage RH range 20-40% was found to be an optimum condition for roll compacting three lactose powders, as it resulted in a minimum amount of fines in the

  5. Effect of Ekabor 2 powder on the mechanical properties of pure iron powder metal compacts

    Directory of Open Access Journals (Sweden)

    Altintaş, Ayberk

    2016-09-01

    Full Text Available Ekabor 2 powder of different weights, used by V type powder mixture was mixed with pure iron powder. Specimens were created by dry pressing into die followed by cold isostatic press at a pressure of 100 bar for purpose of resizing. The conventional sintering process at 900 °C and 950 °C was carried out for 4 h using conventional furnaces. Specimens were gradually cooled by air. The sintered pellets were examined in terms of density, wear abrasion, surface roughness and hardness at 900 °C and 950 °C. Microstructure of pellets was observed with optic microscope. The results show that the hardness gradually increased with additions of 0 wt. % to 10 wt. % of Ekabor 2 however, after 10 wt. %, this hardness tended to decrease.Se mezclaron diferentes cantidades de polvo denominado “Ekabor 2”, el cual se utiliza en mezclas de polvo tipo V, con hierro puro en polvo. La muestras se obtuvieron por prensado en seco seguido de prensa isostática en frío a una presión de 100 bar, con el objeto de redimensionar la muestra. Se llevó a cabo el proceso de sinterización convencional a 900 °C y 950 °C durante 4 h utilizando hornos convencionales. Las muestras se enfriaron gradualmente en aire. Las pastillas sinterizadas (pellets se examinaron en términos de densidad, resistencia a la abrasión, rugosidad y dureza a 900 °C y 950 °C. Se observó la microestructura de las pastillas por microscopía óptica. Los resultados mostraron un aumento gradual de la dureza con la adición de 0 % en peso a 10% en peso de polvo Ekabor 2. Sin embargo, para mayores cantidades del 10% en peso se observó una tendencia a disminuir en la dureza.

  6. Effect of Production Conditions of Wood Powder on Bending Properties of Wood Powder Molding Material without Adhesive

    Science.gov (United States)

    Imanishi, Hiroshi; Soma, Naho; Yamashita, Osamu; Miki, Tsunehisa; Kanayama, Kozo

    The effect of production conditions of wood powder on the bending properties of wood powder molding material was investigated. Wood powder was produced by milling wood into powder under conditions of different temperatures (25°C, 100°C) and moisture contents (0%MC, about 30%MC). Molding materials were produced from wood powder in stream atmosphere of high temperature and high pressure (175°C, 900kPa) using self-bonding ability of the wood powder. Adhesives, such as a synthetic resin, were not used. To evaluate the bending properties of the molding materials, the modulus of elasticity and the bending strength were examined by static three-point bending test. As for the characteristic of wood particle, in case of wood particle produced by milling wood under a condition of high temperature and high moisture content (100°C and about 30%MC), tendencies for intercellular layer to be exposed on surface of a particle and for the aspect ratio of particles to be large were confirmed. And in that case, the molding material showed the highest value in modulus of elasticity and bending strength. It is highly probable that the inprovement of the self-bonding ability of wood powder and the increase of the aspect ratio of wood particle take part in the improvement of strength properties of molding material.

  7. Predictive Simulation of Process Windows for Powder Bed Fusion Additive Manufacturing: Influence of the Powder Bulk Density.

    Science.gov (United States)

    Rausch, Alexander M; Küng, Vera E; Pobel, Christoph; Markl, Matthias; Körner, Carolin

    2017-09-22

    The resulting properties of parts fabricated by powder bed fusion additive manufacturing processes are determined by their porosity, local composition, and microstructure. The objective of this work is to examine the influence of the stochastic powder bed on the process window for dense parts by means of numerical simulation. The investigations demonstrate the unique capability of simulating macroscopic domains in the range of millimeters with a mesoscopic approach, which resolves the powder bed and the hydrodynamics of the melt pool. A simulated process window reveals the influence of the stochastic powder layer. The numerical results are verified with an experimental process window for selective electron beam-melted Ti-6Al-4V. Furthermore, the influence of the powder bulk density is investigated numerically. The simulations predict an increase in porosity and surface roughness for samples produced with lower powder bulk densities. Due to its higher probability for unfavorable powder arrangements, the process stability is also decreased. This shrinks the actual parameter range in a process window for producing dense parts.

  8. A sample holder for in-house X-ray powder diffraction studies of protein powders

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Harris, Pernille; Ståhl, Kenny

    2011-01-01

    A sample holder for handling samples of protein for in-house X-ray powder diffraction (XRPD) analysis has been made and tested on lysozyme. The use of an integrated pinhole reduced the background, and good signal-to-noise ratios were obtained from only 7 l of sample, corresponding to approximately...... 2-3 mg of dry protein. The sample holder is further adaptable to X-ray absorption spectroscopy (XAS) measurements. Both XRPD and XAS at the Zn K-edge were tested with hexameric Zn insulin....

  9. Review of the Methods for Production of Spherical Ti and Ti Alloy Powder

    Science.gov (United States)

    Sun, Pei; Fang, Zhigang Zak; Zhang, Ying; Xia, Yang

    2017-10-01

    Spherical titanium alloy powder is an important raw material for near-net-shape fabrication via a powder metallurgy (PM) manufacturing route, as well as feedstock for powder injection molding, and additive manufacturing (AM). Nevertheless, the cost of Ti powder including spherical Ti alloy has been a major hurdle that prevented PM Ti from being adopted for a wide range of applications. Especially with the increasing importance of powder-bed based AM technologies, the demand for spherical Ti powder has brought renewed attention on properties and cost, as well as on powder-producing processes. The performance of Ti components manufactured from powder has a strong dependence on the quality of powder, and it is therefore crucial to understand the properties and production methods of powder. This article aims to provide a cursory review of the basic techniques of commercial and emerging methods for making spherical Ti powder. The advantages as well as limitations of different methods are discussed.

  10. Single-crystal vanadium pentoxide nanowires.

    Science.gov (United States)

    Gao, Shaokang; Chen, Yuzhen; Luo, Haiyan; Jiang, Lilong; Ye, Binghuo; Wei, Mingdeng; Wei, Kemei

    2008-07-01

    Single-crystal V2O5 nanowires were successfully synthesized from the starting materials V6O13 powder and water. The experimental results indicate that high purity nanowires can be obtained using this simple synthetic route in absence of templates or catalysts. The diameter of the nanowires was found to be ca. 20 approximately 60 nm and the length up to several tens of micrometers, and the phases of nanowires were determined by XRD and TEM measurements.

  11. Net Shape Rapid Manufacturing Using Nano Encapsulated Powders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this STTR is to determine the capability of Net Shape LENS processing with Nano-coated powders. The unique composites produced using regualr...

  12. Net Shape Rapid Manufacturing Using Nano Encapsulated Powders Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase II program is developing NET Shape components from Encapsulated Powders. Significant advances in Phase I for various materials and in net shape processing...

  13. For Diabetics, Nasal Powder Fixed Severe Low Blood Sugar

    Science.gov (United States)

    ... For Diabetics, Nasal Powder Fixed Severe Low Blood Sugar New product much easier to use than rescue ... News) -- For many people with diabetes, low blood sugar levels are a serious health risk, but researchers ...

  14. Synthesis and characterization of nanoboron powders prepared with ...

    Indian Academy of Sciences (India)

    % hydrochloric acid (only one) to remove impurities. Boron powders were obtained after centrifuging, decanting, washing and drying operations. Sample was characterized by inductively coupled plasma (ICP), energy-dispersive spectroscopy, ...

  15. Green biosynthesis of silver nanoparticles using Curcuma longa tuber powder

    National Research Council Canada - National Science Library

    Shameli, Kamyar; Ahmad, Mansor Bin; Zamanian, Ali; Sangpour, Parvanh; Shabanzadeh, Parvaneh; Abdollahi, Yadollah; Zargar, Mohsen

    2012-01-01

    .... In this study, silver nanoparticles were biosynthesized from aqueous silver nitrate through a simple and eco-friendly route using Curcuma longa tuber-powder extracts, which acted as a reductant...

  16. 21 CFR 872.6660 - Porcelain powder for clinical use.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6660 Porcelain powder for clinical use... removable dentures, of jacket crowns, facings, and veneers. The device is used in prosthetic dentistry by...

  17. Powder XRD investigations on dotriacontane in mixtures: Phase ...

    Indian Academy of Sciences (India)

    Abstract. Powder XRD investigations on dotriacontane-decane and dotriacontane-decanol mixtures are made. Phase strength, phase separation and formation of superlattices are discussed. The role of tunnel-like defects is considered.

  18. Optimization of precursor powders for manufacturing Bi-2223/Ag tapes

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C H [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China); Yoo, J M [Materials Engineering Department, Korea Institute of Machinery and Materials, 66 Sangnam-Dong, Changwon (Korea, Republic of); Ko, J W [Materials Engineering Department, Korea Institute of Machinery and Materials, 66 Sangnam-Dong, Changwon (Korea, Republic of); Chung, H S [Department of Molecular Science and Technology, Ajou University (Korea, Republic of); Qiao, G W [Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang (China)

    2003-01-01

    The phase assemblage and particle sizes of precursor powders have been optimized in a sequence for fabricating Ag/BSCCO-2223 composite tapes. Firstly, an optimal calcination temperature was determined based on the experimental results. Then, the precursors calcined at the optimal temperature were ball-milled for different dwell times to obtain varied particle sizes. The effects of both the phase assemblages and particle sizes of the precursor powder on the phase formation, microstructure and transport J{sub c} of Bi-2223/Ag tapes have been investigated. The results show that the precursor phase assemblage has a large impact on the reaction routes, microstructure, and J{sub c} property. Meanwhile, a fine powder is beneficial for the grain growth, alignment, and J{sub c} enhancement in fully reacted tapes. The best J{sub c} was achieved in the tape made from the powder after optimizing the phase assemblage and particle size.

  19. A New Coating Process for Production of Coated Magnesium Powders

    National Research Council Canada - National Science Library

    2008-01-01

    .... In brief, Task 1 involved the construction and assembly of the coating system and supporting infrastructure, which was used for the scale-up and production of 1-lb batches of coated magnesium powder...

  20. Optimization of precursor powders for manufacturing Bi-2223/Ag tapes

    Science.gov (United States)

    Jiang, C. H.; Yoo, J. M.; Ko, J. W.; Chung, H. S.; Qiao, G. W.

    2003-01-01

    The phase assemblage and particle sizes of precursor powders have been optimized in a sequence for fabricating Ag/BSCCO-2223 composite tapes. Firstly, an optimal calcination temperature was determined based on the experimental results. Then, the precursors calcined at the optimal temperature were ball-milled for different dwell times to obtain varied particle sizes. The effects of both the phase assemblages and particle sizes of the precursor powder on the phase formation, microstructure and transport Jc of Bi-2223/Ag tapes have been investigated. The results show that the precursor phase assemblage has a large impact on the reaction routes, microstructure, and Jc property. Meanwhile, a fine powder is beneficial for the grain growth, alignment, and Jc enhancement in fully reacted tapes. The best Jc was achieved in the tape made from the powder after optimizing the phase assemblage and particle size.

  1. Porous mandrels provide uniform deformation in hydrostatic powder metallurgy

    Science.gov (United States)

    Gripshover, P. J.; Hanes, H. D.

    1967-01-01

    Porous copper mandrels prevent uneven deformation of beryllium machining blanks. The beryllium powder is arranged around these mandrels and hot isostatically pressed to form the blanks. The mandrels are then removed by leaching.

  2. Characterization Of The Graded Microstructure In Powder Sintered Porous Titanium

    Directory of Open Access Journals (Sweden)

    Oak J.-J.

    2015-06-01

    Full Text Available The proposed sintering process produce porosity and functional graded microstructure in the sinterd titanium powders. Titanium powders with different micro sizes were sintered at the proposed temperature region at 1200 and 1300°C for 2h. The apatite-forming on the graded microstructure is observed by immersion test in Hanks balanced salt soluion at 37°C. Sintering condition of titanium powders is estimated by thermogravitmetry-differential thermal analysis (TG-DTA. The synthersied surface structures and apatite-forming ability were characterized by a field emission scanning electron microscopy (FE-SEM observation and energy dispersive X-ray spectroscopy (EDS analysis. As results, these graded microstructure of sintered porous titanium powders reveals apatite-forming ability as osseointegration by calcification in Hanks balanced salt soluion(HBSS at 37°C.

  3. Moisture Sorption Isotherms of Yogurt Powder Containing Candied Chestnut Puree

    Directory of Open Access Journals (Sweden)

    Aslı Zungur Bastıoğlu

    2016-08-01

    Full Text Available Yogurt powder was produced by freeze drying and with added candied chestnut puree at ratios of 5, 10, and 20 % by weight. Moisture sorption isotherms of yogurt powder samples, plain (YP, and containing 5, 10, 20% candied chestnut puree (CCP were determined at 25°C using the standard, static-gravimetric method. The experimental adsorption data of yogurt powders at 25°C were fitted to 14 sorption equations which are most widely used to fit experimental sorption data of various food materials. The parameters of the sorption models were estimated from the experimental results by using the nonlinear regression analysis. The GAB model gave the closet fit to the sorption data of freeze dried yogurt powders with candied chestnut puree at 25°C. BET, Ferro Fanton, Henderson, Halsey, Oswin and Modified Oswin models are also acceptable for describing the adsorption isotherms for freeze dried yogurt with candied chestnut puree at 25°C.

  4. Investigation of cell parameters, microstructures and electrochemical behaviour of LiMn{sub 2}O{sub 4} normal and nano powders

    Energy Technology Data Exchange (ETDEWEB)

    Kamarulzaman, N.; Yusoff, R.; Kamarudin, N.; Shaari, N.H.; Abdul Aziz, N.A. [Centre for Nanomaterials Research, Institute of Science, Faculty of Applied Sciences, Universiti Technologi MARA, 40450 Shah Alam, Selangor (Malaysia); Bustam, M.A. [Chemical Engineering Programme, Universiti Teknologi Petronas, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Blagojevic, N.; Elcombe, M.; Blackford, M.; Avdeev, M. [Australian Nuclear Science and Technology Organization, Lucas Heights Science and Technology Centre, Menai, NSW 2234 (Australia); Arof, A.K. [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2009-03-01

    Nano materials are usually difficult to prepare. This work presents a simple way of preparing LiMn{sub 2}O{sub 4} nano powders using the high-energy ball milling method. This method has the advantage of producing pure, single-phase and crystalline nano powders. The milling method is carefully controlled to avoid unwanted chemical reactions that may change the stoichiometry of the material. Nano powders of between 30 and 50 nm are obtained. Structural studies of the nano powders, as well as the more conventional micron-sized LiMn{sub 2}O{sub 4}, are made using X-ray diffraction and neutron diffraction methods. Electrochemical evaluation of the materials is undertaken with a three-probe cyclic voltammetry technique and galvanostatic charge-discharge measurements. Structural studies reveal that not only are the crystallites of the nano powders much reduced in size from the normal powders, but their cell parameters are also smaller. The performance characteristics of the nano material show an improvement over that of the micron-sized material by about 17% in the 1st cycle and 70.6% in the 5th cycle, at which the capacity is 132 mAh g{sup -1}. The normal material suffers from severe capacity fading but the nano material shows much improved capacity retention. (author)

  5. Phase, crystal struture and sintering behavior of shock-synthesized Pb(Zr 0.95Ti 0.05)O 3 powders

    Science.gov (United States)

    Wang, Junxia; Yang, Shiyuan; Wang, Jin; He, Hongliang; Xiong, Ying; Chen, Feng

    2010-12-01

    With a cylindrical shock-wave-loading technique, the single perovskite-phase Pb(Zr 0.95Ti 0.05)O 3 powders (PZT 95/5) were synthesized by shock-induced chemical reactions in heterogeneous multi-material powder mixtures of Pb 3O 4, ZrO 2 and TiO 2. The phase and crystal structure of as-synthesized powders were characterized by X-ray diffraction (XRD) and fourier transform infrared (FT-IR) analysis. And the microstructure and electrical properties of PZT 95/5 ceramics prepared with as-synthesized PZT powders at different sintering temperature were analyzed. The results showed that the shock-wave-induced a large quantity of lattice defects and distortion of the crystal structure in the shock-synthesized PZT powders, which could enhance the sintering activity. Thus, the optimal density and electrical properties of PZT ceramics prepared with as-synthesized powders could be obtained at a sintering temperature of 1200-1225 °C for 3 h, significantly lower than the sintering temperature of PZT 95/5 ceramics prepared by conventional solid-state reaction.

  6. Peculiarities of chemical composition of sainfoin seeds powder

    OpenAIRE

    Natalia Aleksandrovna Tarasenko; Elena Aleksandrovna Butina; Evgeny Olegovich Gerasimenko

    2015-01-01

    This paper is devoted to studying chemical composition of the powder of the seeds of non-traditional legume, sainfoin. The experimental studies showed that crushed seeds of sainfoin make a flowing fine powder of light brown color with a pleasant unpronounced specific smell with floral notes. The taste is grassy with the after-taste typical for legumes. The chemical composition of sainfoin seeds is dominated by proteins and fiber, and fat content does not exceed 8%. The total content of amino-...

  7. Characterization of cohesive powders for bulk handling and DEM modelling

    OpenAIRE

    Thakur, S.C.; Imole, Olukayode Isaiah; Wojtkowski, Mateusz Bronislaw; Magnanimo, Vanessa; Montes, E.C.; Ramaioli, Marco; Ahmadian, H.; Ooi, J.Y.; Bischoff, M; Ramm, E.; Onate, E.; Owen, R; Wriggers, P.

    2013-01-01

    The flow behaviour of granular materials is relevant for many industrial applications including the pharmaceutical, chemical, consumer goods and food industries. A key issue is the accurate characterisation of these powders under different loading conditions and flow regimes, for example in mixers, pneumatic conveyors and silo filling and discharge. This paper explores the experimental aspects of cohesive powder handling at different compaction levels and flow regimes, namely inertial and qua...

  8. Durability Enhancement Of SCC With Waste Glass Powder

    OpenAIRE

    Matos,Ana Mafalda; Ramos, Telma; Nunes, Sandra; Sousa-Coutinho, Joana

    2016-01-01

    Self compacting concrete (SCC) requires a large quantity of fine materials compared to common concrete. In this work waste glass powder was used to replace (50%) of filler required. Two types of SCC were manufactured, a control SCC type (CTL) using cement and limestone filler and another with glass powder replacing 50% of the filler. Mechanical and durability properties, namely, compressive strength, resistivity, chloride ion penetration, carbonation, capillary water absorption and oxygen per...

  9. Sintering nanodisperse zirconium powders with various stabilizing additives

    Directory of Open Access Journals (Sweden)

    Antsiferov V.N.

    2011-01-01

    Full Text Available Effect of various stabilizing additives on sintering kinetics of nanodisperse powders was studied by thermomechanical analysis. Temperature ranges of the most intense shrinking, characteristic points of shrinking rate changes were established. Peaks characterizing the most intense shrinking of nanodisperse zirconium powder samples were shown to allow to arrange the stabilizing additives as follows: Y2O3→CeO2→TiO2.

  10. Standard specification for Nuclear-Grade aluminum oxide powder

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This specification provides the chemical and physical requirements for nuclear-grade aluminum oxide powder intended for fabrication into shapes for nuclear applications. Two specific uses for which this powder is intended are Al2O3 pellets and Al2O 3 − B4C composite pellets for use as thermal insulator or burnable neutron absorbers, respectively. 1.2 The material described herein shall be particulate in nature.

  11. Particle-based Powder-snow Avalanche Simulation Using GPU

    OpenAIRE

    Yndestad, Leif Kåre Hornnes

    2011-01-01

    The main focus of this thesis was the simulation of a powder-snow avalanche flow. The simulation were implemented using the particle-based simulation solution SPH, from a mathematical model describing powder-snow flow dynamics. The simulation was accelerated by applying the computational power of the GPU, in order to provide a faster simulation time than would have been achieved on the CPU.

  12. Evaluation of milk powder quality by protein oxidative modifications.

    Science.gov (United States)

    Scheidegger, Dana; Radici, Paola M; Vergara-Roig, Víctor A; Bosio, Noelia S; Pesce, Silvia F; Pecora, Rolando P; Romano, José C P; Kivatinitz, Silvia C

    2013-06-01

    The objective of the present research was to evaluate commercially available milk powders according to their protein oxidative modifications and antioxidant capacity, and to evaluate if these characteristics are related to physical quality parameters such as dispersibility or stability during storage. Fifteen commercially processed spray-dried milk powders were evaluated: 6 whole milk powders (WMP), 4 skim milk powders (SMP), and 5 infant formula powders (IFP). Protein oxidative status was measured as protein carbonyl (PC) content, dityrosine content, and extent of protein polymerization. The level of PC was slightly lower in SMP than in WMP, whereas IFP had more than twice as much PC as WMP (2.8 ± 0.4, 2.1 ± 0.2, and 6.5 ± 1.3 nmol/mg of protein for WMP, SMP, and IFP, respectively). No differences were detected in dityrosine accumulation. Although all the possible pairs of parameters were tested for correlations, we found that 4 parameters were linked: PC, whey content, protein aggregate level, and dispersibility. After 9 mo of storage at -20°C or room temperature, all milk samples were analyzed to evaluate changes in protein oxidative status (PC, dityrosine, and protein integrity) and related parameters. Compared with the initial condition, PC increased in all tested samples after 9 mo of storage at -20°C or at room temperature. Stored milk powders had increased PC and decreased dispersibility compared with prestorage levels. Our results highlight the importance of protein oxidative status in milk powder and its relationship to other related quality parameters, such as protein integrity and dispersibility. Our findings suggest that the understanding of such relationships could help in developing quality differentiation for different types of milk powders in the product market. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Whey powder: glassy state and spray drying conditions

    OpenAIRE

    Ítalo Tuler Perrone; Arlan Caldas Pereira Silveira; Evandro Martins; Antônio Fernandes de Carvalho; Pierre Schuck,

    2017-01-01

    The knowledge on spray drying of whey has significantly changed during the last 20 years. Industries started to apply more technical and scientific information for whey powder production. The main problems in whey powder are: sticking and caking during production and storage, which lead to decrease of the yield. These problems are based on the control of the glassy state during the dehydration process and storage. Due to the importance of the glass transition, spray drying parameters should b...

  14. Polymer-Cement Composites Containing Waste Perlite Powder

    OpenAIRE

    Paweł Łukowski

    2016-01-01

    Polymer-cement composites (PCCs) are materials in which the polymer and mineral binder create an interpenetrating network and co-operate, significantly improving the performance of the material. On the other hand, the need for the utilization of waste materials is a demand of sustainable construction. Various mineral powders, such as fly ash or blast-furnace slag, are successfully used for the production of cement and concrete. This paper deals with the use of perlite powder, which is a burde...

  15. Liposomal dry powders as aerosols for pulmonary delivery of proteins.

    Science.gov (United States)

    Lu, Dongmei; Hickey, Anthony J

    2005-12-21

    The purpose of this research was to develop liposomal dry powder aerosols for protein delivery. The delivery of stable protein formulations is essential for protein subunit vaccine delivery, which requires local delivery to macrophages in the lungs. Beta-glucuronidase (GUS) was used as a model protein to evaluate dry powder liposomes as inhaled delivery vehicles. Dimyristoyl phosphatylcholine:cholesterol (7:3) was selected as the liposome composition. The lyophilization of liposomes, micronization of the powders, aerosolization using a dry powder inhaler (DPI), and in vitro aerodynamic fine particle fraction upon collection in a twin-stage liquid impinger were evaluated. After lyophilization and jet-milling, the total amount of GUS and its activity, representing encapsulation efficiency and stability, were evaluated. The GUS amount and activity were measured and compared with freshly-prepared liposomes in the presence of mannitol, 43% of initial GUS amount, 29% of GUS activity after lyophilization and 36% of GUS amount, 22% of activity after micronization were obtained. Emitted doses from dry powder inhaler were 53%, 58%, 66%, and 73% for liposome powder:mannitol carrier ratios of 1:0, 1:4, 1:9, and 1:19. Fifteen percent of the liposome particles were less than 6.4 mum in aerodynamic diameter. The results demonstrate that milled liposome powders containing protein molecules can be aerosolized effectively at a fixed flow rate. Influences of different cryoprotectants on lyophilization of protein liposome formulations are reported. The feasibility of using liposomal dry powder aerosols for protein delivery has been demonstrated but further optimization is required in the context of specific therapeutic proteins.

  16. Formulating powder-device combinations for salmeterol xinafoate dry powder inhalers.

    Science.gov (United States)

    Hassoun, Mireille; Ho, Shirlene; Muddle, Joanna; Buttini, Francesca; Parry, Mark; Hammond, Mark; Forbes, Ben

    2015-07-25

    Using salmeterol xinafoate (SX) as an active pharmaceutical ingredient, the effects of carrier lactose particle type, total lactose fines content and device resistance on dry powder inhaler performance were investigated in vitro. To mimic drug levels in commercial preparations, interactive mixtures containing 0.58% w/w SX were prepared by low shear tumble mixing. Three types of milled inhalation grade lactose were used (Lactohale(®) LH 200, Respitose(®) ML006 and ML001) and the concentration of fine lactose (Lactohale(®) 300) added was varied. The in vitro deposition of each mixture was studied using a next generation impactor and inhaler devices exhibiting different resistances, Rotahaler(®)MMAD) ± geometric standard deviation (GSD) and fine particle fraction (FPF). Increases of up to eight-fold in FPF were observed with increasing intrinsic fine lactose content. The addition of extra fine lactose increased the FPF further, although the effect diminished as more fines were added. The Aerolizer produced the best aerosol performance with any given powder blend, although suitable formulations were identified for each device as defined by the a priori success criteria: >80% ED and MMAD ± GSD between 1-5 μm. The results confirmed the factors under investigation to be important determinants of product performance, but demonstrated using realistic conditions how individual factor impact may be enhanced or mitigated by inter-dependency. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Preparation and Characterization of Zinc Materials Prepared by Powder Metallurgy

    Directory of Open Access Journals (Sweden)

    Michaela Krystýnová

    2017-09-01

    Full Text Available The use of zinc-based materials as biodegradable materials for medical purposes is offered as a possible alternative to corrosion-less resistant magnesium-based materials. Zinc powders with two different particle sizes (7.5 µm and 150 µm were processed by the methods of powder metallurgy: cold pressing, cold pressing followed by sintering and hot pressing. The microstructure of prepared materials was evaluated in terms of light optical microscopy, and the mechanical properties were analyzed with Vickers microhardness testing and three-point bend testing. Fractographic analysis of broken samples was performed with scanning electron microscopy. Particle size was shown to have a significant effect on compacts mechanical properties. The deformability of 7.5 µm particle size powder was improved by increased temperature during the processing, while in the case of larger powder, no significant influence of temperature was observed. Bending properties of prepared materials were positively influenced by elevated temperature during processing and correspond to the increasing compacting pressures. Better properties were achieved for pure zinc prepared from 150 µm particle size powder compared to materials prepared from 7.5 µm particle size powder.

  18. Permanent magnet microstructures using dry-pressed magnetic powders

    Science.gov (United States)

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

    2013-07-01

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

  19. Study on the storage of Ginseng powder by. gamma. -irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Min, O.N. (Seoul National Univ. (Republic of Korea))

    1982-04-01

    To determine the effect of ..gamma..-irradiation on the microorganisms destruction and the changes of general constituents of Ginseng Powder, three samples were analyzed at 1st and 3rd month after ..gamma..-irradation. The results were as follows: 1. Total bacterial counts were decreased during storage as the irradation dose increased. It seems that about 300 Krad was satisfactory to the regulation of ginseng powder. (5.0 x 10/sup 4/ per g) 2. Coliform group was also decreased during storage as the irradiation dose increased. Coliform group was not detected at the irradiation dose higher than 500 Krad. 3. Total bacterial counts and coliform group were in proportion to the content of moisture in Ginseng powder. 4. The contents of moisture, ash, crude protein, crude lipid and total sugar in Ginseng powder during storage had nearly no changes. 5. The content of reducing sugar in Ginseng powder during storage had a tendency to increase as the irradiation dose increased. 6. The content of amino-nitrogen in Ginseng powder during storage had a tendency to decrease as the irradiation dose increased.

  20. On iron contamination in mechanically alloyed Cr-Si powders

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Bruno B. [Universidade do Vale do Paraiba, Instituto de Pesquisa e Desenvolvimento, Sao Jose dos, Campos-SP, CEP 12244-000 (Brazil); Rodrigues, Geovani [Faculdade de Engenharia Quimica de Lorena, Departamento de Engenharia de Materiais, Caixa Postal 116, Lorena-SP, CEP 12600-970 (Brazil); Coelho, Gilberto C. [Faculdade de Engenharia Quimica de Lorena, Departamento de Engenharia de Materiais, Caixa Postal 116, Lorena-SP, CEP 12600-970 (Brazil); Ramos, Alfeu S. [Universidade do Vale do Paraiba, Instituto de Pesquisa e Desenvolvimento, Sao Jose dos, Campos-SP, CEP 12244-000 (Brazil)]. E-mail: alfeu@univap.br

    2005-09-25

    The present work reports on iron contamination and phase transformation during high-energy ball milling from high-purity elemental powder Cr-25Si, Cr-37.5Si, Cr-50Si, and Cr-66Si mixtures (at%) and their subsequent heat treatment. Samples were characterized in the as-milled state as well as after heat treatment by X-ray diffraction (XRD), scanning electron microscopy (SEM), and microanalysis via energy dispersive spectrometry (EDS). Only Cr peaks were observed in Cr-25Si and Cr-37.5Si powders after milling for 200 h, suggesting that amorphous phases can be formed. In Cr-50Si and Cr-66Si powders, the CrSi and CrSi{sub 2} phases were formed during ball milling, respectively. In Cr-25Si and Cr-50Si milled powders, heat-treated at 1200 deg. C for 4 h, the formation of the Cr{sub 3}Si and CrSi phases dissolving up to 15 and 16.9 at%Fe, respectively, was noted. In addition, the ternary Cr{sub 9}Fe{sub 9}Si{sub 2} phase was also formed in heat-treated Cr-25Si powders. A small amount of Cr{sub 5}Si{sub 3} and CrSi{sub 2} was formed in heat-treated Cr-37.5Si and Cr-66Si powders, respectively.

  1. Supercritical fluid molecular spray thin films and fine powders

    Science.gov (United States)

    Smith, Richard D.

    1988-01-01

    Solid films are deposited, or fine powders formed, by dissolving a solid material into a supercritical fluid solution at an elevated pressure and then rapidly expanding the solution through a short orifice into a region of relatively low pressure. This produces a molecular spray which is directed against a substrate to deposit a solid thin film thereon, or discharged into a collection chamber to collect a fine powder. The solvent is vaporized and pumped away. Solution pressure is varied to determine, together with flow rate, the rate of deposition and to control in part whether a film or powder is produced and the granularity of each. Solution temperature is varied in relation to formation of a two-phase system during expansion to control porosity of the film or powder. A wide variety of film textures and powder shapes are produced of both organic and inorganic compounds. Films are produced with regular textural feature dimensions of 1.0-2.0 .mu.m down to a range of 0.01 to 0.1 .mu.m. Powders are formed in very narrow size distributions, with average sizes in the range of 0.02 to 5 .mu.m.

  2. Effects of powder flow properties on capsule filling weight uniformity.

    Science.gov (United States)

    Osorio, Juan G; Muzzio, Fernando J

    2013-09-01

    Filling capsules with the right amount of powder ingredients is an important quality parameter. The purpose of this study was to develop effective laboratory methods for characterizing flow properties of pharmaceutical powder blends and correlating such properties to weight variability in filled capsules. The methods used for powder flow characterization were bulk and tapped density, gravitational displacement rheometer (GDR) flow index, Freeman Technology V.4 (FT4) powder rheometer compressibility, FT4 basic flow energy (BFE), and cohesion parameters [cohesion, (C) and flow factor (ffc)] measured in a shear cell also using the FT4. Capsules were filled using an MG2-G140 continuous nozzle dosator capsule-filling machine. Powder flow properties were the most predominant factors affecting the weight and weight variability in the filled capsules. Results showed that the weight variability decreased with increasing bulk and tapped density, ffc and BFE, while the weight variability increased with increasing compressibility, cohesion and GDR flow index. Powder flow properties of the final blends were significantly correlated to the final capsule weight and weight variability of the filled capsules.

  3. Dry Powder Precursors of Cubic Liquid Crystalline Nanoparticles (cubosomes)

    Science.gov (United States)

    Spicer, Patrick T.; Small, William B.; Small, William B.; Lynch, Matthew L.; Burns, Janet L.

    2002-08-01

    Cubosomes are dispersed nanostructured particles of cubic phase liquid crystal that have stimulated significant research interest because of their potential for application in controlled-release and drug delivery. Despite the interest, cubosomes can be difficult to fabricate and stabilize with current methods. Most of the current work is limited to liquid phase processes involving high shear dispersion of bulk cubic liquid crystalline material into sub-micron particles, limiting application flexibility. In this work, two types of dry powder cubosome precursors are produced by spray-drying: (1) starch-encapsulated monoolein is produced by spray-drying a dispersion of cubic liquid crystalline particles in an aqueous starch solution and (2) dextran-encapsulated monoolein is produced by spray-drying an emulsion formed by the ethanol-dextran-monoolein-water system. The encapsulants are used to decrease powder cohesion during drying and to act as a soluble colloidal stabilizer upon hydration of the powders. Both powders are shown to form (on average) 0.6 μm colloidally-stable cubosomes upon addition to water. However, the starch powders have a broader particle size distribution than the dextran powders because of the relative ease of spraying emulsions versus dispersions. The developed processes enable the production of nanostructured cubosomes by end-users rather than just specialized researchers and allow tailoring of the surface state of the cubosomes for broader application.

  4. Development of equipment for fabricating DUPIC fuel powder

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Ho; Yang, M. S.; Park, J. J.; Lee, J. W.; Kim, J. H.; Cho, K. H.; Lee, D. Y.; Lee, Y. S.; Na, S. H

    1999-06-01

    The powder fabrication processes, as the first stage of manufacturing DUPIC (Direct Use of PWR spent fuel In CANDU) fuel, consist of the slitting of spent PWR fuel rods, REOX (Oxidation and REduction of Oxide Fuels) processing to produce the powder feedstock, the milling of the produced powder, the granulation of the milled powder, and the mixing of the granulated powder with pressing lubricants. All these processes should be conducted by remote means in a hot-cell environment where the direct human access is limited to the strictest minimum due to the high radioactivity. This report describe the development of the equipment for fabricating DUPIC fuel powder. These equipment are Slitting Machine, Oxidation and Reduction (OREOX) Furnace, Mill, Roll Compactor, and Mixer. Remote design concept was applied to all the equipment for use in the M6 hot-cell of the IMEF. Mechanical design considerations and capabilities of the equipment for remote operation and maintenance are presented. First prototypes were developed and installed in the DUPIC full scale mock-up and tested using a master-slave manipulator. Redesign and reconstruction were made on each equipment based on mock-up test results. The remote technology acquired through this research was utilized in developing other equipment for DUPIC fuel fabrication, thereby improving safety and increasing productivity. This technology could also be extended to the area of remote handling equipment development for use in hazardous environments. (author). 14 refs., 9 tabs., 21 figs.

  5. Titanium Metal Powder Production by the Plasma Quench Process

    Energy Technology Data Exchange (ETDEWEB)

    R. A. Cordes; A. Donaldson

    2000-09-01

    The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

  6. Experimental and numerical studies on laser-based powder deposition of slurry erosion resistant materials

    Science.gov (United States)

    Balu, Prabu

    cracking issue, and 3) the effect of composition and composition gradient of Ni and WC on the slurry erosion resistance over a wide range of erosion conditions. This thesis presents a set of numerical and experimental methods in order to address the challenges mentioned above. A three-dimensional (3-D) computational fluid dynamics (CFD) based powder flow model and three vision based techniques were developed in order to visualize the process of feeding the Ni-WC powder in the LBPD process. The results provide the guidelines for efficiently feeding the Ni-WC composite powder into the laser-formed molten pool. The finite element (FE) based experimentally verified 3-D thermal and thermo-mechanical models are developed in order to understand the thermal and stress evolutions in Ni-WC composite material during the LBPD process. The models address the effect of the process variables, preheating temperature, and different mass fractions of WC in Ni on thermal cycles and stress distributions within the deposited material. The slurry erosion behavior of the single and multilayered deposits of Ni-WC composite material produced by the LBPD process is investigated using an accelerated slurry erosion testing machine and a 3-D FE dynamic model. The verified model is used to identify the appropriate composition and composition gradient of Ni-WC composite material required to achieve erosion resistance over a wide range of erosion conditions.

  7. Spectrochemical analysis of powdered biological samples using transversely excited atmospheric carbon dioxide laser plasma excitation

    Science.gov (United States)

    Zivkovic, Sanja; Momcilovic, Milos; Staicu, Angela; Mutic, Jelena; Trtica, Milan; Savovic, Jelena

    2017-02-01

    The aim of this study was to develop a simple laser induced breakdown spectroscopy (LIBS) method for quantitative elemental analysis of powdered biological materials based on laboratory prepared calibration samples. The analysis was done using ungated single pulse LIBS in ambient air at atmospheric pressure. Transversely-Excited Atmospheric pressure (TEA) CO2 laser was used as an energy source for plasma generation on samples. The material used for the analysis was a blue-green alga Spirulina, widely used in food and pharmaceutical industries and also in a few biotechnological applications. To demonstrate the analytical potential of this particular LIBS system the obtained spectra were compared to the spectra obtained using a commercial LIBS system based on pulsed Nd:YAG laser. A single sample of known concentration was used to estimate detection limits for Ba, Ca, Fe, Mg, Mn, Si and Sr and compare detection power of these two LIBS systems. TEA CO2 laser based LIBS was also applied for quantitative analysis of the elements in powder Spirulina samples. Analytical curves for Ba, Fe, Mg, Mn and Sr were constructed using laboratory produced matrix-matched calibration samples. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used as the reference technique for elemental quantification, and reasonably well agreement between ICP and LIBS data was obtained. Results confirm that, in respect to its sensitivity and precision, TEA CO2 laser based LIBS can be successfully applied for quantitative analysis of macro and micro-elements in algal samples. The fact that nearly all classes of materials can be prepared as powders implies that the proposed method could be easily extended to a quantitative analysis of different kinds of materials, organic, biological or inorganic.

  8. Reconstituted yogurt from yogurt cultured milk powder mix has better overall characteristics than reconstituted yogurt from commercial yogurt powder

    National Research Council Canada - National Science Library

    Song, Lijie; Aryana, Kayanush J

    2014-01-01

    For manufacture of commercial yogurt powder, yogurt has to go through a drying process, which substantially lowers the yogurt culture counts, so the potential health benefits of the yogurt culture bacteria are reduced...

  9. Improved pharmacokinetics of sumatriptan with Breath Powered™ nasal delivery of sumatriptan powder.

    Science.gov (United States)

    Obaidi, Mohammad; Offman, Elliot; Messina, John; Carothers, Jennifer; Djupesland, Per G; Mahmoud, Ramy A

    2013-09-01

    The purpose of this study was to directly compare the pharmacokinetic (PK) profile of 22-mg sumatriptan powder delivered intranasally with a novel Breath Powered™ device (11 mg in each nostril) vs a 20-mg sumatriptan liquid nasal spray, a 100-mg oral tablet, and a 6-mg subcutaneous injection. A prior PK study found that low doses of sumatriptan powder delivered intranasally with a Breath Powered device were efficiently and rapidly absorbed. An early phase clinical trial with the same device and doses found excellent tolerability with high response rates and rapid onset of pain relief, approaching the benefits of injection despite significantly lower predicted drug levels. An open-label, cross-over, comparative bioavailability study was conducted in 20 healthy subjects at a single center in the USA. Following randomization, fasted subjects received a single dose of each of the 4 treatments separated by a 7-day washout. Blood samples were taken pre-dose and serially over 14 hours post-dose for PK analysis. Quantitative measurement of residuals in used Breath Powered devices demonstrated that the devices delivered 8±0.9 mg (mean±standard deviation) of sumatriptan powder in each nostril (total dose 16 mg). Although the extent of systemic exposure over 14 hours was similar following Breath Powered delivery of 16-mg sumatriptan powder and 20-mg liquid nasal spray (area under the curve [AUC]0-∞ 64.9 ng*hour/mL vs 61.1 ng*hour/mL), sumatriptan powder, despite a 20% lower dose, produced 27% higher peak exposure (Cmax 20.8 ng/mL vs 16.4 ng/mL) and 61% higher exposure in the first 30 minutes compared with the nasal spray (AUC0-30 minutes 5.8 ng*hour/mL vs 3.6 ng*hour/mL). The magnitude of difference is larger on a per-milligram basis. The absorption profile following standard nasal spray demonstrated bimodal peaks, consistent with lower early followed by higher later absorptions. In contrast, the profile following Breath Powered delivery showed higher

  10. Multiple micronutrient powders for home (point-of-use) fortification of foods in pregnant women.

    Science.gov (United States)

    Suchdev, Parminder S; Peña-Rosas, Juan Pablo; De-Regil, Luz Maria

    2015-06-19

    It is estimated that 32 million pregnant women suffer from anaemia worldwide. Due to increased metabolic demands, pregnant women are particularly vulnerable to anaemia and vitamin and mineral deficiencies, leading to adverse health effects in both the mother and her baby. Despite the demonstrated benefits of prenatal supplementation with iron and folic acid or multiple micronutrients, poor adherence to routine supplementation has limited the effectiveness of this intervention in many settings. Micronutrient powders for point-of-use fortification are packed, single-dose sachets containing vitamins and minerals that can be added onto prepared food to improve its nutrient profile. The use of multiple micronutrient powders for point-of-use fortification of foods in pregnant women could be an alternative intervention to prenatal micronutrient supplementation. To assess the effects of prenatal home (point-of-use) fortification of foods with multiple micronutrient powders on maternal and newborn health. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015) and the International Clinical Trials Registry Platform (ICTRP) (31 January 2015). We also contacted relevant agencies to identify ongoing and unpublished studies. Randomised controlled trials (both individual and cluster randomisation) and quasi-randomised trials, irrespective of language or publication status.The intervention was micronutrient powders for point-of-use fortification of foods, containing at least three micronutrients with one of them being iron, provided to pregnant women of any gestational age and parity. Five comparison groups were considered: no intervention/placebo, iron and folic acid supplements, iron-only supplements, folic-acid only supplements, and multiple micronutrients in supplements. Two review authors independently assessed the eligibility of studies, extracted and checked data accuracy, and assessed the risk of bias of included studies. Our search

  11. Synthesis of alumina powder by the urea-glycine-nitrate combustion process: a mixed fuel approach to nanoscale metal oxides

    Science.gov (United States)

    Sharma, Amit; Rani, Amita; Singh, Ajay; Modi, O. P.; Gupta, Gaurav K.

    2014-03-01

    Main objective of present work is to study the efficiency of mixed fuel towards solution combustion synthesis of alumina powder, which otherwise prepared by single fuel and study of properties of final product with mixed fuel approach. Two different fuels, glycine and urea, along with aluminium nitrates have been used to prepare nanophase alumina powder. Different fuel to oxidizer ratios and different percentage combination of two fuels were used to prepare six samples. In all samples, nanoscale particle size obtained. Parameter which continuously changes the results of various characterisations is percentage combination of two fuels. In case where percentage of urea is higher than glycine reaction takes place with high exothermicity and hence crystallinity in product phase, whereas glycine promotes amorphous character. With mixed fuel approach, crystallinity can be enhanced easily, by calcinations of powder product at low temperature, because due to mixed urea and glycine, there is already some fraction of crystallinity observed. Overall mixed fuel approach has ability to produce nanophase alumina powder with wide range of particles size.

  12. BaTiO3 thick fi lms obtained by tape casting from powders prepared by the oxalate route

    Directory of Open Access Journals (Sweden)

    Adelina Ianculescu

    2009-06-01

    Full Text Available BaTiO3 powders were prepared by co-precipitation via oxalate route. The size, morphology and particle size distribution of the oxalate powders have been optimized by the control of different synthesis parameters during the precipitation reaction (nature of salts, concentration of different solutions, aging time. The single phase BaTiO3 oxide particles were obtained after a thermal decomposition of the as-synthesized powders at 850°C for 4 hours under air atmosphere. Oxide powders with a suitable specifi c surface area were selected in order to obtain thick fi lms by the tape casting technique. The microstructure and dielectric properties of the thick films varied obviously depending on the deposition-calcination-sintering cycle used. A double depositioncalcination cycle followed by sintering, as well as a two step deposition-calcination-sintering procedure was used in order to improve the compactness and therefore, the dielectric behaviour. A higher dielectric constant value (~ 750 and lower dielectric losses (~ 2 % were achieved at room temperature and at 1 kHz frequency for the dense, double-deposited fi lm obtained after two deposition-calcination-sintering cycles. For this film, a superior value of the dielectric constant (~ 1100, almost frequency independent in the frequency range of 100 Hz – 10 kHz was gained also at the ferroelectric-paraelectric phase transition temperature of 130°C.

  13. Bond Strength of White Mineral Trioxide Aggregate with and without Disodium Hydrogen Phosphate with Different Liquid-to-Powder Ratios.

    Science.gov (United States)

    Mokhtari, Hadi; Jafarizadeh, Sara; Mokhtari Zonouzi, Hamid Reza; Lotfi, Mehrdad; Forough Reyhani, Mohammad; Sohrabi, Aydin

    2017-01-01

    Mineral trioxide aggregate (MTA) can be used in the treatment of irritated vital pulp and repair of root perforations. However, the initial reaction of inflammatory cells to this material and also its setting time are not ideal. Studies have shown that disodium hydrogen phosphate (DHP), decreases the setting time of MTA, with no effect on its pH. This study was undertaken to evaluate the effect of DHP on push-out bond strength of MTA at different liquid-to-powder ratios. A total of 120 samples were prepared from the middle third of the roots of single-rooted teeth for evaluation of push-out bond strength. The push-out bond strength was measured in both groups after 72 h at different liquid-to-powder ratios, including 0.33:1, 0.5:1 and 0.6:1. Factorial ANOVA and Tukey's HSD post-hoc tests were used to compare the differences between the independent groups. Statistical significant was set at PMTA and MTA+DHP groups were 10.96±5.78 and 13.32±5.03, respectively. Tukey's HSD post-hoc test revealed significant differences between the two groups. Furthermore, there were no interactive effect between material and the liquid: powder ratio. Incorporation of DHP into MTA resulted in an increase in push-out bond strength of MTA, and an increase in liquid-to-powder ratio resulted in a decrease in push-out bond strength.

  14. 40 CFR 471.100 - Applicability; description of the powder metals subcategory.

    Science.gov (United States)

    2010-07-01

    ... powder metals subcategory. 471.100 Section 471.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY Metals Powders Subcategory § 471.100 Applicability; description of the powder metals...

  15. Evaluation of ring shear testing as a characterization method for powder flow in small-scale powder processing equipment.

    Science.gov (United States)

    Søgaard, Søren Vinter; Pedersen, Troels; Allesø, Morten; Garnaes, Joergen; Rantanen, Jukka

    2014-11-20

    Powder flow in small-scale equipment is challenging to predict. To meet this need, the impact of consolidation during powder flow characterization, the level of consolidation existing during discharge of powders from a tablet press hopper and the uncertainty of shear and wall friction measurements at small consolidation stresses were investigated. For this purpose, three grades of microcrystalline cellulose were used. Results showed that powder flow properties depend strongly on the consolidation during testing. The consolidation during discharge in terms of the major principal stress and wall normal stress were approximately 200 Pa and 114 Pa, respectively, in the critical transition from the converging to the lower vertical section of the hopper. The lower limit of consolidation for the shear and wall friction test was approximately 500 Pa and 200 Pa, respectively. At this consolidation level, the wall and shear stress resolution influences the precision of the measured powder flow properties. This study highlights the need for an improved experimental setup which would be capable of measuring the flow properties of powders under very small consolidation stresses with a high shear stress resolution. This will allow the accuracy, precision and applicability of the shear test to be improved for pharmaceutical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Comparison of the oxygen reduction on a diamond powder supported electrocatalysts and Pani modified diamond powder supported electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ozenler, S.S.; Kadirgan, F. [Istanbul Technical Univ., Istanbul (Turkey). Dept. of Chemistry

    2006-07-01

    A study was conducted in which a catalyst was prepared based on the nanostructured Mo{sub x}Ru{sub y}Se{sub z} compounds was prepared by thermolysis of their carbonyl compounds in organic solvents. The activities towards the oxygen reduction of diamond powder supported Mo{sub x}Ru{sub y}Se{sub z} based electrodes and Polyaniline (Pani) modified diamond powder supported Mo{sub x}Ru{sub y}Se{sub z} based cathode electrodes for proton exchange membrane fuel cells (PEMFC) were then compared by electrochemical methods on carbon paper and carbon textile. The synthesized catalyst was supported either by nano diamond powder or Pani modified nano diamond powder. Polyaniline modified electrodes were fabricated electrochemically on diamond powder supported electrodes. The oxygen reduction activity and methanol tolerance of both electrodes was compared with platinum electrode at elevated temperatures. The oxygen reduction reaction rate was found to be much higher with the polyaniline coated diamond powder matrix. 5 refs.

  17. Macro- and Microelemental Composition and Toxicity of Unsweetened Natural Cocoa Powder in Sprague-Dawley Rats

    Directory of Open Access Journals (Sweden)

    Isaac Julius Asiedu-Gyekye

    2016-01-01

    Full Text Available Unsweetened natural cocoa powder (UNCP is a pulverized high-grade powder of compressed solid blocks which remains after extraction. Little scientific data is available concerning its safety despite the presence of potential toxic elements. Elemental composition in UNCP was analyzed with ED-XRF spectroscopy. Single oral high dose toxicity study was conducted on adult male Sprague-Dawley rats (150 g by the limit test method. One group received water and the test group 2000 mg/kg UNCP. All animals were observed for 14 days and then euthanized for haematological, biochemical, and histopathological examinations. Thirty-eight (38 elements were found in UNCP. There was an increase in HDL cholesterol (p0.05, alkaline phosphatase (p0.05. Haematological changes were not significant. Histopathological analysis showed no toxic effect on the heart, liver, kidney, lungs, testis, and spleen. Intestinal erosion was observed in the test group. UNCP appears to be relatively safe when taken as a single oral high dose of 2000 mg/kg b.w.t. in rats. Caution should however be exercised at high doses due to the high elemental content of copper and high possibility of intestinal lining erosion.

  18. Steady-state tryptophan fluorescence spectroscopy study to probe tertiary structure of proteins in solid powders.

    Science.gov (United States)

    Sharma, Vikas K; Kalonia, Devendra S

    2003-04-01

    The purpose of this work was to obtain information about protein tertiary structure in solid state by using steady state tryptophan (Trp) fluorescence emission spectroscopy on protein powders. Beta-lactoglobulin (betaLg) and interferon alpha-2a (IFN) powder samples were studied by fluorescence spectroscopy using a front surface sample holder. Two different sets of dried betaLg samples were prepared by vacuum drying of solutions: one containing betaLg, and the other containing a mixture of betaLg and guanidine hydrochloride. Dried IFN samples were prepared by vacuum drying of IFN solutions and by vacuum drying of polyethylene glycol precipitated IFN. The results obtained from solid samples were compared with the emission scans of these proteins in solutions. The emission scans obtained from protein powders were slightly blue-shifted compared to the solution spectra due to the absence of water. The emission scans were red-shifted for betaLg samples dried from solutions containing GuHCl. The magnitude of the shifts in lambda(max) depended on the extent of drying of the samples, which was attributed to the crystallization of GuHCl during the drying process. The shifts in the lambda(max) of the Trp emission spectrum are associated with the changes in the tertiary structure of betaLg. In the case of IFN, the emission scans obtained from PEG-precipitated and dried sample were different compared to the emission scans obtained from IFN in solution and from vacuum dried IFN. The double peaks observed in this sample were attributed to the unfolding of the protein. In the presence of trehalose, the two peaks converged to form a single peak, which was similar to solution emission spectra, whereas no change was observed in the presence of mannitol. We conclude that Trp fluorescence spectroscopy provides a simple and reliable means to characterize Trp microenvironment in protein powders that is related to the tertiary conformation of proteins in the solid state. This study shows

  19. Comparative study of kinetics of adsorption of methylene blue from aqueous solutions using cinnamon plant (Cinnamonum zeylanicum) leaf powder and pineapple peel powder

    National Research Council Canada - National Science Library

    Patil, Satish D; Renukdas, S; Patel, N.T

    2012-01-01

    ...) leaf powder (CPLP) and Pineapple (Ananas Comosus) peel powder (PPP) was investigated. Different parameters such as initial sorbate concentration, adsorbent dosage, pH, contact time, agitation speed, temperature and particle size...

  20. Titania and silica powders produced in a counterflow diffusion flame

    Energy Technology Data Exchange (ETDEWEB)

    Rulison, A.J.; Miquel, P.F.; Katz, J.L. [Department of Chemical Engineering, The Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    1996-12-01

    Earlier publications describe the counterflow diffusion flame burner and its unique capability to produce oxide particles having certain structures, such as spheres of one material coated with another, spheres of one composition with attached bulbs of another composition, and uniform multicomponent mixtures. Here we describe the production and properties of bulk quantities of powders produced using this burner. Measurements were made of specific surface area and, for titania, of phase composition. It was found that the controls over powder characteristics used in other forms of flame-synthesis are equally effective in the counterflow diffusion flame burner. We found that the specific surface area of both silica and titania powders decrease with increasing precursor concentrations. Transmission electron microscopy analysis of the titania powders indicates that the mean size of the particles that comprise these powders increases with increasing concentration. These trends are consistent with the collision-coalescence theory of particle growth. In addition, the crystalline phase of titania can be controlled by selecting the appropriate feed stream. For example, over the ranges TiCl{sub 4} precursor concentrations tested, feeding it only into the {ital oxidizer} stream yields mainly {ital anatase} TiO{sub 2} powders, while feeding only into the {ital fuel} stream yields mainly {ital rutile} TiO{sub 2} powders. These trends can be explained by the known atmosphere-dependent anatase-rutile transformation. The present data demonstrate that, in addition to its unique capability to produce certain particle shapes and morphologies, the counterflow diffusion flame burner can be manipulated to produce either of the major commercial titania phases, and also silica, with a wide range of specific surface areas. {copyright} {ital 1996 Materials Research Society.}

  1. The Use of Alginate in Lemon Extract Effervescent Powder Production

    Directory of Open Access Journals (Sweden)

    Murdinah

    2015-11-01

    Full Text Available Study on the use of alginate in lemon (Citrus medica var lemon extract effervescent powder production has conducted. The aims of the research are to determine the optimum concentration of alginate used in lemon extract effervescent powder to produced best product and acceptance consumen.The lemon extract effervescent powder formula consisted of lemon extract powder, sucrose, aspartame, salt and effervescent mix (citric acid-tartrat acid-sodium bicarbonat. The alginate used in this study was extracted from Sargassum filipendula sea weed. The concentration of alginate used in lemon effervescent powder production was varied from 1; 2; 3 and 4%. The parameters observed to see the quality of the product were moisture content, ash content, pH, viscosity and organoleptic value (flavor, taste, viscosity, effec effervescent, effect sparkle and acceptance. Analysis of dietary fiber, sugar content, vitamin C content, total titratable acids, TPC and E.Coli to the best product. The result showed that the higher the concentration of alginate used in lemon effervescent powder production, the higher viscousness and the lower the organoleptic value. The optimum concentration of alginate used in the lemon extract effervescent powder processing was 1%. The characteristic this product 7.60% moisture content, 0.86% insoluble dietary fiber , 7.92% soluble dietary fiber, 3.74% sugar content, 55,26 mg/100 g vitamin C, 134.15 mL 0.1 NaOH/100 mL total titratable acids, 20 cPs viscosity, <2.5x102 coloni/mL TPC and E.Coli negative.

  2. Comparison between powder and slices diffraction methods in teeth samples

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Marcos V.; Barroso, Regina C. [Universidade do Estado do Rio de Janeiro (IF/UERJ), RJ (Brazil). Inst. de Fisica. Dept. de Fisica Aplicada; Porto, Isabel M. [Universidade Estadual de Campinas (FOP/UNICAMP), Piracicaba, SP (Brazil). Fac. de Odontologia. Dept. de Morfologia; Gerlach, Raquel F. [Universidade de Sao Paulo (FORP/USP), Rieirao Preto, SP (Brazil). Fac. de Odontologia. Dept. de Morfologia, Estomatologia e Fisiologia; Costa, Fanny N. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LIN/COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2011-07-01

    Propose different methods to obtain crystallographic information about biological materials are important since powder method is a nondestructive method. Slices are an approximation of what would be an in vivo analysis. Effects of samples preparation cause differences in scattering profiles compared with powder method. The main inorganic component of bones and teeth is a calcium phosphate mineral whose structure closely resembles hydroxyapatite (HAp). The hexagonal symmetry, however, seems to work well with the powder diffraction data, and the crystal structure of HAp is usually described in space group P63/m. Were analyzed ten third molar teeth. Five teeth were separated in enamel, detin and circumpulpal detin powder and five in slices. All the scattering profile measurements were carried out at the X-ray diffraction beamline (XRD1) at the National Synchrotron Light Laboratory - LNLS, Campinas, Brazil. The LNLS synchrotron light source is composed of a 1.37 GeV electron storage ring, delivering approximately 4x10{sup -1}0 photons/s at 8 keV. A double-crystal Si(111) pre-monochromator, upstream of the beamline, was used to select a small energy bandwidth at 11 keV . Scattering signatures were obtained at intervals of 0.04 deg for angles from 24 deg to 52 deg. The human enamel experimental crystallite size obtained in this work were 30(3)nm (112 reflection) and 30(3)nm (300 reflection). These values were obtained from measurements of powdered enamel. When comparing the slice obtained 58(8)nm (112 reflection) and 37(7)nm (300 reflection) enamel diffraction patterns with those generated by the powder specimens, a few differences emerge. This work shows differences between powder and slices methods, separating characteristics of sample of the method's influence. (author)

  3. Single scan vector prediction in selective laser melting

    NARCIS (Netherlands)

    Wits, Wessel Willems; Bruins, R.; Terpstra, L.; Huls, R.A.; Geijselaers, Hubertus J.M.

    2015-01-01

    In selective laser melting (SLM) products are built by melting layers of metal powder successively. Optimal process parameters are usually obtained by scanning single vectors and subsequently determining which settings lead to a good compromise between product density and build speed. This paper

  4. Pharmacokinetic Comparison of a Unit Dose Dry Powder Inhaler with a Multidose Dry Powder Inhaler for Delivery of Fluticasone Furoate.

    Science.gov (United States)

    Mehta, Rashmi; Moore, Alison; Riddell, Kylie; Joshi, Shashidhar; Chan, Robert

    2017-10-01

    The unit dose dry powder inhaler (UD-DPI) is being considered as an alternative inhaler platform that, if developed, has the potential to improve access to inhaled respiratory medicines in developing countries. This study compared the systemic exposure of fluticasone furoate after delivery from the UD-DPI with that from the ELLIPTA ® inhaler. This open-label, five-way cross-over, randomized, single-dose study in healthy subjects evaluated fluticasone furoate systemic exposure of three dose strengths (using four inhalations), 4 × 80 μg [320 μg], 4 × 100 μg [400 μg], and 4 × 140 μg [560 μg]), and two percentages of drug in lactose blends (0.6% and 0.8% by weight) after delivery from the UD-DPI compared with systemic exposures from the ELLIPTA inhaler (4 × 100 μg [400 μg] dose, 0.8% lactose blend). The primary treatment comparisons were area under the concentration-time curve from time 0 to 6 hours [AUC 0-6 ] and maximum plasma concentration [C max ]. After single-dose administration of fluticasone furoate, systemic exposure was lower from all UD-DPI formulations versus the ELLIPTA inhaler in terms of both AUC 0-6 [AUC 0-6 geometric least squares mean (GLM) ratios confidence interval (90% CI) for: UD-DPI (400 μg 0.8% blend)/ELLIPTA: 0.61 (0.55-0.67) and C max GLM (90% CI) for: UD-DPI (400 μg 0.8% blend)/ELLIPTA: 0.56 (0.49-0.64)]. Systemic exposures were ∼10% lower for fluticasone furoate UD-DPI for the 0.8% blend versus the 0.6% blend [GLM ratio (90% CI); 0.90 (0.81-1.00) for AUC 0-6 and 0.89 (0.77-1.01) for C max ], and increasing doses of fluticasone furoate from the UD-DPI showed systemic exposures that were approximately dose proportional. All treatments were well tolerated. Fluticasone furoate systemic exposure was lower from the UD-DPI than from the ELLIPTA inhaler, but the UD-DPI formulations did demonstrate detectable systemic levels and approximate dose proportionality. Together with the good tolerability

  5. The effect of the particle shape and structure on the flowability of electrolytic copper powder. II. The experimental verification of the model of the representative powder particle

    Directory of Open Access Journals (Sweden)

    MILUTIN C. OBRADOVIC

    2003-10-01

    Full Text Available An analysis of the effects of the shape, surface structure and size distribution of particles on the flowability of the copper powder was performed. It is shown that the most important property of the particles of a powder, regarding the flowability of the powder, is the surface structure of the particles.

  6. Analytical method development for powder characterization: Visualization of the critical drug loading affecting the processability of a formulation for direct compression

    DEFF Research Database (Denmark)

    Hirschberg, Cosima; Sun, Calvin Changquan; Rantanen, Jukka

    2016-01-01

    Characterization of particulate systems (powders) is one of the remaining scientific challenges. Evaluation of powder behaviour is often empirical and the decision-making processes are experience-based. There is a need for development of analytical instrumentation enabling more fundamental...... was investigated using a ring shear tester and tablets were prepared at four different compression pressures using a single punch tablet press. Thereby, a material sparing screening approach was developed to estimate the influence of APIs on behaviour of a given DC formulation. Additionally, this approach...

  7. Production of fine powder from silk by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Ishida, Kazushige; Kamiishi, Youichi [Textile Research Inst. of Gunma, Kiryu, Gunma (Japan)

    2000-09-01

    To produce silk fine powder, silk fibroin fibers were irradiated with an accelerated electron beam. Though unirradiated silk fibers were not pulverized at all, irradiated silk fibers were able to be crushed only by physical means using a ball mill. In the dose range of 250- 1000 kGy, as the dose to silk fibroin increased, the conversion rate from fiber to powder was increased. The electron microscope observation showed that the particle size of silk powder was less than 10 micrometers, and that those particles composed aggregate. Although silk fibroin fiber was not soluble in water, silk powders from fiber irradiated 500 kGy dissolved more than 50 weight %. Amino acid analysis of soluble fraction in silk powder showed that Gly content is lower than in normal silk and other amino acids contents except for Ala are 1.5 times as large as in normal silk. From these results, it is reasonable to suppose that irradiation and pulverization decomposed Gly and Ala. (author)

  8. Rapid process for manufacturing of aluminum nitride powder

    Energy Technology Data Exchange (ETDEWEB)

    Weimer, A.W.; Cochran, G.A.; Eisman, G.A.; Henley, J.P.; Hook, B.D.; Mills, L.K. [Dow Chemical Co., Midland, MI (United States). Ceramics and Advanced Materials Research; Guiton, T.A.; Knudsen, A.K.; Nicholas, R.N.; Volmering, J.E.; Moore, W.G. [Dow Chemical Co., Midland, MI (United States). Advanced Ceramics Lab.

    1994-01-01

    A rapid, direct nitridation process for the manufacture of sinterable aluminum nitride (AIN) powder was developed at the pilot scale. Atomized aluminum metal and nitrogen gas were heated and reacted rapidly to synthesize AIN while they passed through the reaction zone of a transport flow reactor. The heated walls of the reactor simultaneously initiated the reaction and removed the generated heat to control the exotherm. Several variations of the process were required to achieve high conversion and reduce wall deposition of the product. The fine AIN powder produced did not require a postreaction grinding step to reduce particle size. However, a secondary heat treatment, following a mild milling step to expose fresh surface, was necessary to ensure complete conversion of the aluminum. In some instances, a final air classification step to remove large particles was necessary to promote densification by pressure less sintering. The AIN powder produced was pressure less sintered with 3 wt% yttria to fabricate fully dense parts which exhibited high thermal conductivity. The powder was shown to be less sinterable than commercially available carbothermally produced powders

  9. Transport and deposition of cohesive pharmaceutical powders in human airway

    Directory of Open Access Journals (Sweden)

    Wang Yuan

    2017-01-01

    Full Text Available Pharmaceutical powders used in inhalation therapy are in the size range of 1-5 microns and are usually cohesive. Understanding the cohesive behaviour of pharmaceutical powders during their transportation in human airway is significant in optimising aerosol drug delivery and targeting. In this study, the transport and deposition of cohesive pharmaceutical powders in a human airway model is simulated by a well-established numerical model which combines computational fluid dynamics (CFD and discrete element method (DEM. The van der Waals force, as the dominant cohesive force, is simulated and its influence on particle transport and deposition behaviour is discussed. It is observed that even for dilute particle flow, the local particle concentration in the oral to trachea region can be high and particle aggregation happens due to the van der Waals force of attraction. It is concluded that the deposition mechanism for cohesive pharmaceutical powders, on one hand, is dominated by particle inertial impaction, as proven by previous studies; on the other hand, is significantly affected by particle aggregation induced by van der Waals force. To maximum respiratory drug delivery efficiency, efforts should be made to avoid pharmaceutical powder aggregation in human oral-to-trachea airway.

  10. Technological and practical challenges of dry powder inhalers and formulations.

    Science.gov (United States)

    Hoppentocht, M; Hagedoorn, P; Frijlink, H W; de Boer, A H

    2014-08-01

    In the 50 years following the introduction of the first dry powder inhaler to the market, several developments have occurred. Multiple-unit dose and multi-dose devices have been introduced, but first generation capsule inhalers are still widely used for new formulations. Many new particle engineering techniques have been developed and considerable effort has been put in understanding the mechanisms that control particle interaction and powder dispersion during inhalation. Yet, several misconceptions about optimal inhaler performance manage to survive in modern literature. It is, for example still widely believed that a flow rate independent fine particle fraction contributes to an inhalation performance independent therapy, that dry powder inhalers perform best at 4 kPa (or 60 L/min) and that a high resistance device cannot be operated correctly by patients with reduced lung function. Nevertheless, there seems to be a great future for dry powder inhalation. Many new areas of interest for dry powder inhalation are explored and with the assistance of new techniques like computational fluid dynamics and emerging particle engineering technologies, this is likely to result in a new generation of inhaler devices and formulations, that will enable the introduction of new therapies based on inhaled medicines. Copyright © 2014. Published by Elsevier B.V.

  11. Flowability of lignocellusic biomass powders: influence of torrefaction intensity

    Science.gov (United States)

    Pachón-Morales, John; Colin, Julien; Pierre, Floran; Champavert, Thibaut; Puel, François; Perré, Patrick

    2017-06-01

    The poor flowability of powders produced from raw lignocellulosic biomass may be an economically issue for the production of second-generation biofuels. Torrefaction is a pre-treatment step of the gasification process that improves the physical characteristics of biomass by making it more coal-like. Particularly, the loss of resilience allows a reduction of the grinding energy consumption and is likely to improve the flow behaviour of woody powders. In this study, we investigated the effect of particle size and shape distribution on flow properties (unconfined yield stress and flowability factor) of powder from raw and torrefied biomass (Picea abies). Several intensities of torrefaction were tested, and its extent was quantified by the global mass loss, chosen as synthetic indicator of torrefaction intensity (its accounts for both the temperature level and the residence time). The intensity of torrefaction shifts the particle size distribution towards smaller sizes. An effect on the circularity and aspect ratio was also observed. A strong, positive correlation was obtained between the measured flowability of biomass powders at different consolidation stresses and the intensity of heat treatment. These results confirm the interest of torrefaction as a pre-treatment step and aim to provide new knowledge on rheological properties of biomass powders.

  12. Sintering Behaviors of Carbon Nanotubes—Aluminum Composite Powders

    Directory of Open Access Journals (Sweden)

    Biao Chen

    2016-09-01

    Full Text Available Carbon nanotubes (CNTs are promising reinforcements for fabricating aluminum (Al matrix composites with outstanding properties. The understanding of the consolidation process of CNT–Al composite powders plays a significant role in achieving high performances of bulk composites. In this study, an advanced consolidation technique of spark plasma sintering (SPS was used to fabricate CNT–Al composites with homogeneously dispersed CNTs. The sintering kinetics of pure Al powders and those powders coated with 1 wt % CNTs were studied. By combining the electrical conductivity and relative density results, it was found that the sintering process consisted of two stages with distinct densification rates. The second stage with a much lower rate was governed by the breaking down of alumina films at primary particle boundaries. The activation energy of the controlling second stage increased by 55% in CNT–Al composite powders compared to that of pure Al powder. As a result, CNT addition led to the overall decrease of sintering ability, which raised a challenge in the processing of CNT–Al composites.

  13. [Effects of colorants on yttria stabilized tetragonal zirconia polycrystals powder].

    Science.gov (United States)

    Wang, Bo; Chen, Jianfeng; Zhang, Yanchun; Wang, Ru

    2015-10-01

    To evaluate the effect of Fe2O3 and CeO2 as colorants on yttria stabilized tetragonal zirconia poly-crystals (Y-TZP) powder. The spray granulation slurry of colored zirconia was prepared with different concentrations of Fe2O3 (0.15%) and CeO2 (4%), which were added in Y-TZP. Zirconia powder was made by spray granulation. The powder specimens were divided into three groups: uncolored zirconia, Fe2O3 (0.15%) zirconia, and CeO2 (4%) zirconia. The particle morphologies of the powder specimens were measured with a laser particle size analyzer and an optical microscope. The differences in D50 among the three groups were statistically significant (Pzirconia (Pzirconia showed no significant difference from group CeO2 (P>0.05). Mostly spherical powder was observed in the three groups. Fe2O3 as a colorant can affect particles, whereas CeO2 has no effect.

  14. Interfacial Microstructure and Properties of Steel/Aluminum Powder Additive

    Directory of Open Access Journals (Sweden)

    YUAN Jiang

    2017-09-01

    Full Text Available Based on first-principles density functional theory, the Fe/Al interface model of steel/aluminum laser welding was constructed by layer technique. The Fe/Al interface was studied by metal atom X (X=Sn, Sr, Zr, Ce, La.The results show that Sn, Sr and Ce preferentially displace the Al atoms at the Fe/Al interface, while La and Zr preferentially displace the Fe atoms at the Fe/Al interface. Alloying promotes the transfer of Fe/Al interfacial electrons between different orbits, enhances the ionic bond properties of Fe-Al, improves the Fe/Al interface binding capacity, improves the brittle fracture of Fe/Al interface, and the alloying effect of Sn most notable. On the basis of this, the laser lap welding test of Sn and Zr powder was carried out on 1.4mm thick DC51D+ZF galvanized steel and 1.2mm thick 6016 aluminum alloy specimen. The results show that the addition of powder can promote the flowability of the molten bath and change the composition and microstructure of the joint interface. The tensile strength of the steel/aluminum joint is 327.41MPa and the elongation is 22.93% with the addition of Sn powder, which is obviously improved compared with the addition of Zr powder and without the addition of powder.

  15. Engineered sodium hyaluronate respirable dry powders for pulmonary drug delivery.

    Science.gov (United States)

    Martinelli, Francesco; Balducci, Anna Giulia; Kumar, Abhinav; Sonvico, Fabio; Forbes, Ben; Bettini, Ruggero; Buttini, Francesca

    2017-01-30

    Sodium hyaluronate (HYA) warrants attention as a material for inhalation due to its (i) therapeutic potential, (ii) utility as a formulation excipient or drug carrier, and (iii) ability to target lung inflammation and cancer. This study aimed to overcome formulation and manufacturing impediments to engineer biocompatible spray-dried HYA powders for inhalation. Novel methodology was developed to produce HYA microparticles by spray drying. Different types of surfactant were included in the formulation to improve powder respirability, which was evaluated in vitro using cascade impactors. The individual formulation components and formulated products were evaluated for their biocompatibility with A549 respiratory epithelial cells. The inclusion of stearyl surfactants, 5% w/v, produced the most respirable HYA-powders; FPF 59.0-66.3%. A trend to marginally higher respirability was observed for powders containing stearylamine>stearyl alcohol>cetostearyl alcohol. Pure HYA was biocompatible with A549 cells at all concentrations measured, but the biocompatibility of the stearyl surfactants (based on lethal concentration 50%; LC50) in the MTT assay ranked stearyl alcohol>cetostearyl alcohol>stearylamine with LC50 of 24.7, 13.2 and 1.8μg/mL, respectively. We report the first respirable HYA powders produced by spray-drying. A lead formulation containing 5% stearyl alcohol was identified for further studies aimed at translating the proposed benefits of inhaled HYA into safe and clinically effective HYA products. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  16. Microstructural Development in Al-Si Powder During Rapid Solidification

    Energy Technology Data Exchange (ETDEWEB)

    Genau, Amber Lynn [Iowa State Univ., Ames, IA (United States)

    2004-01-01

    Powder metallurgy has become an increasingly important form of metal processing because of its ability to produce materials with superior mechanical properties. These properties are due in part to the unique and often desirable microstructures which arise as a result of the extreme levels of undercooling achieved, especially in the finest size powder, and the subsequent rapid solidification which occurs. A better understanding of the fundamental processes of nucleation and growth is required to further exploit the potential of rapid solidification processing. Aluminum-silicon, an alloy of significant industrial importance, was chosen as a model for simple eutectic systems displaying an unfaceted/faceted interface and skewed coupled eutectic growth zone, Al-Si powder produced by high pressure gas atomization was studied to determine the relationship between microstructure and alloy composition as a function of powder size and atomization gas. Critical experimental measurements of hypereutectic (Si-rich) compositions were used to determine undercooling and interface velocity, based on the theoretical models which are available. Solidification conditions were analyzed as a function of particle diameter and distance from nucleation site. A revised microstructural map is proposed which allows the prediction of particle morphology based on temperature and composition. It is hoped that this work, by providing enhanced understanding of the processes which govern the development of the solidification morphology of gas atomized powder, will eventually allow for better control of processing conditions so that particle microstructures can be optimized for specific applications.

  17. Luminescent characteristics of praseodymium-doped zinc aluminate powders

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Perez, C.D.; Garcia-Hipolito, M.; Alvarez-Fregoso, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Coyoacan, DF (Mexico); Alvarez-Perez, M.A. [Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, Coyoacan, DF (Mexico); Ramos-Brito, F. [Laboratorio de Materiales Optoelectronicos, DIDe, Centro de Ciencias de Sinaloa, Av. De las Americas No. 2771 Nte. Col. Villa Universidad, Culiacan, Sinaloa (Mexico); Falcony, C. [Centro de Investigaciones y Estudios Avanzados del IPN, Departamento de Fisica, Mexico, DF (Mexico)

    2010-02-15

    In this research, we report the cathodoluminescence (CL) and preliminary photoluminescence (PL) properties of praseodymium-doped zinc aluminate powders. ZnAl{sub 2}O{sub 4}:Pr powders were synthesized by a very simple chemical process. X-ray diffraction spectra indicated a cubic spinel crystalline structure with an average crystallite size of 15 nm. CL properties of the powders were studied as a function of the praseodymium concentration and electron-accelerating potential. In this case, all the cathodoluminescent emission spectra showed main peaks located at 494, 535, 611, 646, and 733 nm, which were associated to the electronic transitions {sup 3}P{sub 0}{yields}{sup 3}H{sub 4}, {sup 3}P{sub 0}{yields}{sup 3}H{sub 5}, {sup 3}P{sub 0}{yields}{sup 3}H{sub 6}, {sup 3}P{sub 0}{yields}{sup 3}F{sub 2}, and {sup 3}P{sub 0}{yields}{sup 3}F{sub 4} of the Pr{sup 3+} ions, respectively. A quenching of the CL, with increasing doping concentration, was observed. Also, an increment on cathodoluminescent emission intensity was observed as the accelerating voltage increased. The PL emission spectrum showed similar characteristics to those of the CL spectra. The chemical composition of the powders, as determined by energy dispersive spectroscopy, is also reported. In addition, the surface morphology characteristics of the powders are shown. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  18. Surface quality analysis of die steels in powder-mixed electrical discharge machining using titan powder in fine machining

    Directory of Open Access Journals (Sweden)

    Banh Tien Long

    2016-06-01

    Full Text Available Improving the quality of surface molds after electrical discharge machining is still being considered by many researchers. Powder-mixed dielectric in electrical discharge machining showed that it is one of the processing methods with high efficiency. This article reports on the results of surface quality of mold steels after powder-mixed electrical discharge machining using titanium powder in fine machining. The process parameters such as electrode material, workpiece material, electrode polarity, pulse on-time, pulse off-time, current, and titanium powder concentration were considered in the research. These materials are most commonly used with die-sinking electrical discharge machining in the manufacture of molds and has been selected as the subject of research: workpiece materials were SKD61, SKT4, and SKD11 mold steels, and electrode materials were copper and graphite. Taguchi’s method is used to design experiments. The influence of the parameters on surface roughness was evaluated through the average value and ratio (S/N. Results showed that the parameters such as electrical current, electrode material, pulse on-time, electrode polarity, and interaction between the electrode materials with concentration powder mostly influence surface roughness and surface roughness at optimal parameters SRopt = 1.73 ± 0.39 µm. Analysis of the surface layer after powder-mixed electrical discharge machining using titanium powder in optimal conditions has shown that the white layer with more uniform thickness and increased hardness (≈861.0 HV, and amount and size of microscopic cracks, is reduced. This significantly leads to the increase in the quality of the surface layer.

  19. Platelet-Rich Plasma Powder: A New Preparation Method for the Standardization of Growth Factor Concentrations.

    Science.gov (United States)

    Kieb, Matthias; Sander, Frank; Prinz, Cornelia; Adam, Stefanie; Mau-Möller, Anett; Bader, Rainer; Peters, Kirsten; Tischer, Thomas

    2017-03-01

    Platelet-rich plasma (PRP) is widely used in sports medicine. Available PRP preparations differ in white blood cell, platelet, and growth factor concentrations, making standardized research and clinical application challenging. To characterize a newly standardized procedure for pooled PRP that provides defined growth factor concentrations. Controlled laboratory study. A standardized growth factor preparation (lyophilized PRP powder) was prepared using 12 pooled platelet concentrates (PCs) derived from different donors via apheresis. Blood samples and commercially available PRP (SmartPrep-2) served as controls (n = 5). Baseline blood counts were analyzed. Additionally, single PCs (n = 5) were produced by standard platelet apheresis. The concentrations of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived growth factor AB (PDGF-AB), transforming growth factor β1 (TGF-β1), insulin-like growth factor 1 (IGF-1), interleukin (IL)-1α, IL-1β, and IL-1 receptor agonist (IL-1RA) were analyzed by enzyme-linked immunosorbent assay, and statistical analyses were performed using descriptive statistics, mean differences, 95% CIs, and P values (analysis of variance). All growth factor preparation methods showed elevated concentrations of the growth factors VEGF, bFGF, PDGF-AB, and TGF-β1 compared with those of whole blood. Large interindividual differences were found in VEGF and bFGF concentrations. Respective values (mean ± SD in pg/mL) for whole blood, SmartPrep-2, PC, and PRP powder were as follows: VEGF (574 ± 147, 528 ± 233, 1087 ± 535, and 1722), bFGF (198 ± 164, 410 ± 259, 151 ± 99, and 542), PDGF-AB (2394 ± 451, 17,846 ± 3087, 18,461 ± 4455, and 23,023), and TGF-β1 (14,356 ± 4527, 77,533 ± 13,918, 68,582 ± 7388, and 87,495). IGF-1 was found in SmartPrep-2 (1539 ± 348 pg/mL). For PC (2266 ± 485 pg/mL), IGF-1 was measured at the same levels of whole blood (2317 ± 711 pg/mL) but was not detectable in PRP

  20. Synthesis of La{sup 3+} doped nanocrystalline ceria powder by urea-formaldehyde gel combustion route

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, M. [Central Glass and Ceramic Research Institute, Kolkata 700 032 (India); Bandyopadhyay, S., E-mail: sbando@cgcri.res.in [Central Glass and Ceramic Research Institute, Kolkata 700 032 (India)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Nano LC synthesized by gel combustion, using urea-formaldehyde fuel for first time. Black-Right-Pointing-Pointer Largely single crystals were produced in average range of 20-30 nm. Black-Right-Pointing-Pointer La{sup 3+} doping increases cell dimension linearly. Black-Right-Pointing-Pointer La{sup 3+} doping introduces ionic point defects but does not change electronic band gap. Black-Right-Pointing-Pointer Presence of Ce{sup 3+} indicates that this synthesis route produces reactive powders. -- Abstract: Nanocrystalline ceria powders doped with various concentrations of lanthanum oxide have been prepared following gel combustion route using for the first time urea-formaldehyde as fuel. The synthesized products were characterized by XRD, FESEM, TEM, PL and UV-vis spectroscopy. Peak positions of XRD were refined and the lattice parameters were obtained by applying Cohen's method. Unit cell parameter increases with concentration of La{sup 3+} ion and the variation is consistently linear. XRD calculations showed the dependence of crystallite size on dopant concentrations at lower level. TEM observation revealed unagglomerated particles to be single crystals in the average range of 20-30 nm. Band gap of the La{sup 3+} doped ceria materials does not change with doping. Spectroscopic experiments proved the existence of Ce{sup 3+} in the formed powder.