Research on manufacturing aluminum - rare earth alloy with a high content of rare earth (> 20% RE) from total rare earth oxides by thermit reduction

International Nuclear Information System (INIS)

Ngo Trong Hiep; Dam Van Tien; Tran Duy Hai; Ngo Xuan Hung and Ly Thanh Vu

2004-01-01

In this report, several theoretical principles of thermit reduction method used for metal oxides to obtain metals, ferroalloys and ligatua with technical purity are presented. Manufacture of aluminum-rare earth alloys by thermit reduction is also described in the report. Data that are generalized based on thermo-kinetic calculation of the thermit reduction and selection of technological flow-sheet based on thermal effect will partly clarify research results in investigating typical features of the process and identify measures to reduce metal loss in discharged slags. (author)

Analysis of a thermite experiment to study low pressure corium dispersion

International Nuclear Information System (INIS)

Wilhelm, D.

2001-08-01

The report describes the recalculation of a thermite experiment in a reduced scale which simulates the discharge of molten core materials out of the pressure vessel of a light water reactor into the open compartments and the dome of the containment. The experiment was performed in the framework of a multinational effort at the Sandia National Laboratory, U.S.A. It is being followed by the DISCO program at the Forschungszentrum Karlsruhe. A computational fluid dynamics code was supplemented with specific models to recalculate the Sandia experiment in order to identify problem areas which need to be addressed in the future. Therefore, a first attempt was undertaken to extrapolate to reactor conditions. This was done in two steps to separate geometric from material scaling relationships. The study shows that important experimental results can be extrapolated according to general scaling laws but that there are sensitivities, especially when replacing thermite by corium. The results show a considerable scatter and a dependence on geometric resolution and dynamics of energy transfer between participating components. (orig.) [de

Calculation of the CAREM reactor with the HUEMUL-PUMA-THERMIT chain of codes; Calculo del reactor CAREM con la cadena de codigos HUEMUL-PUMA-THERMIT

Energy Technology Data Exchange (ETDEWEB)

Notari, Carla; Grant, Carlos R [Comision Nacional de Energia Atomica, General San Martin (Argentina)

2000-07-01

The purpose of the work was the evaluation of the the CAREM 25 reactor core, using a chain of codes (HUEMUL-PUMA-THERMIT) different to the one used in the original design (CONDOR-CITVAP-THERMIT). First, we performed a partial validation of the our codes in lattices similar to CAREM and reproduced a benchmark for simulation of gadolinium burnup. The results were considered satisfactory for this stage of the project. Then, we calculated the core along the normal operating equilibrium cycle and in hot and cold shut-down conditions. The main outcome of our evaluation confirms the general behaviour of the reference calculations except in one important point referring to the cold shut down. In this condition, the failure of one single rod of bank number 13 of the shut down system, leaves the core in a supercritical state at the beginning of the cycle and this anomaly persists during almost a third of the overall cycle. A new design of the core is proposed with minor modifications of the reference one, without introducing new types of fuel elements and keeping the same fuel management scheme. This new core fulfills all the design requirements. (author)

Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

Science.gov (United States)

Tringe, J. W.; Létant, S. E.; Dugan, L. C.; Levie, H. W.; Kuhl, A. L.; Murphy, G. A.; Alves, S. W.; Vandersall, K. S.; Pantoya, M. L.

2013-12-01

Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300-2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%-1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.

Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

International Nuclear Information System (INIS)

Tringe, J. W.; Létant, S. E.; Dugan, L. C.; Levie, H. W.; Kuhl, A. L.; Murphy, G. A.; Alves, S. W.; Vandersall, K. S.; Pantoya, M. L.

2013-01-01

Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300–2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%–1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine

Comparison of Bacillus atrophaeus spore viability following exposure to detonation of C4 and to deflagration of halogen-containing thermites

Energy Technology Data Exchange (ETDEWEB)

Tringe, J. W.; Létant, S. E.; Dugan, L. C.; Levie, H. W.; Kuhl, A. L.; Murphy, G. A.; Alves, S. W.; Vandersall, K. S. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States); Pantoya, M. L. [Mechanical Engineering Department, Texas Tech University, Lubbock, Texas 79409 (United States)

2013-12-21

Energetic materials are being considered for the neutralization of spore-forming bacteria. In this study, the neutralization effects of a monomolecular explosive were compared to the effects of halogen-containing thermites. Bacillus atrophaeus spores were exposed to the post-detonation environment of a 100 g charge of the military explosive C-4 at a range of 50 cm. These tests were performed in the thermodynamically closed environment of a 506-l barometric calorimeter. Associated temperatures were calculated using a thermodynamic model informed by calculations with the Cheetah thermochemical code. Temperatures in the range of 2300–2800 K were calculated to persist for nearly the full 4 ms pressure observation time. After the detonation event, spores were characterized using optical microscopy and the number of viable spores was assessed. Results showed live spore survival rates in the range of 0.01%–1%. For the thermite tests, a similar, smaller-scale configuration was employed that examined the spore neutralization effects of two thermites: aluminum with iodine pentoxide and aluminum with potassium chlorate. Only the former mixture resulted in spore neutralization. These results indicate that the detonation environment produced by an explosive with no chemical biocides may provide effective spore neutralization similar to a deflagrating thermite containing iodine.

Fabrication of hard cermets by in-situ synthesis and infiltration of metal melts into WC powder compacts

Directory of Open Access Journals (Sweden)

Guanghua Liu

2017-12-01

Full Text Available Hard carbide cermets are prepared by in-situ synthesis and infiltration of metal melts into WC powder compacts. Ni–W and Ni–W–Cr metal melts are in-situ synthesized from thermite reactions and infiltrated into WC powder compacts under high-gravity. During the infiltration, W in the metal melts reacts with WC to form W2C, and more W2C and W are observed at the upper parts of the cermets than the lower parts. The cermets show a maximum hardness of 15.4 GPa, which is higher than most commercial cemented carbides, although they are not fully dense and have a porosity of 15–20%.

Ab initio molecular dynamics study of thermite reaction at Al and CuO nano-interfaces at different temperatures

Science.gov (United States)

Tang, Cui-Ming; Chen, Xiao-Xu; Cheng, Xin-Lu; Zhang, Chao-Yang; Lu, Zhi-Peng

2018-05-01

The thermite reaction at Al/CuO nano-interfaces is investigated with ab initio molecular dynamics calculations in canonical ensemble at 500 K, 800 K, 1200 K and 1500 K, respectively. The reaction process and reaction products are analyzed in terms of chemical bonds, average charge, time constants and total potential energy. The activity of the reactants enhances with increasing temperature, which induces a faster thermite reaction. The alloy reaction obviously expands outward at Cu-rich interface of Al/CuO system, and the reaction between Al and O atoms obviously expands outward at O-rich interface as temperature increases. Different reaction products are found at the outermost layer of different interfaces in the Al/CuO system. In generally, the average charge of the outer layer aluminum atoms (i.e., Al1, Al2, Al5 and Al6) increases with temperature. The potential energy of Al/CuO system decreases significantly, which indicates that drastic exothermic reaction occurs at the Al/CuO system. This research enhances fundamental understanding in temperature effect on the thermite reaction at atomic level, which can potentially open new possibilities for its industrial application.

Characterisation of Ceramic-Coated 316LN Stainless Steel Exposed to High-Temperature Thermite Melt and Molten Sodium

Science.gov (United States)

Ravi Shankar, A.; Vetrivendan, E.; Shukla, Prabhat Kumar; Das, Sanjay Kumar; Hemanth Rao, E.; Murthy, S. S.; Lydia, G.; Nashine, B. K.; Mallika, C.; Selvaraj, P.; Kamachi Mudali, U.

2017-11-01

Currently, stainless steel grade 316LN is the material of construction widely used for core catcher of sodium-cooled fast reactors. Design philosophy for core catcher demands its capability to withstand corium loading from whole core melt accidents. Towards this, two ceramic coatings were investigated for its application as a layer of sacrificial material on the top of core catcher to enhance its capability. Plasma-sprayed thermal barrier layer of alumina and partially stabilised zirconia (PSZ) with an intermediate bond coat of NiCrAlY are selected as candidate material and deposited over 316LN SS substrates and were tested for their suitability as thermal barrier layer for core catcher. Coated specimens were exposed to high-temperature thermite melt to simulate impingement of molten corium. Sodium compatibility of alumina and PSZ coatings were also investigated by exposing samples to molten sodium at 400 °C for 500 h. The surface morphology of high-temperature thermite melt-exposed samples and sodium-exposed samples was examined using scanning electron microscope. Phase identification of the exposed samples was carried out by x-ray diffraction technique. Observation from sodium exposure tests indicated that alumina coating offers better protection compared to PSZ coating. However, PSZ coating provided better protection against high-temperature melt exposure, as confirmed during thermite melt exposure test.

Prompt striations observed in a barium thermite release at 335 km

International Nuclear Information System (INIS)

Simons, D.J.; Pongratz, M.B.; Smith, G.M.; Barasch, G.E.; Fitzgerald, T.J.

1981-01-01

Three barium clouds have been released from a single rocket at altitudes of 335, 443, and 535 km. The releases were by means of barium thermite injection. Adding the different cross-field velocity components of the rocket at each of the releases resulted in barium clouds with different kinetic velocity distributions. The barium cloud with the most peaked velocity distribution striated promptly, in good agreement with theoretical predictions based on a kinetic plasma instability. Details of the data analysis and experiment are discussed

Calculation of the CAREM reactor with the HUEMUL-PUMA-THERMIT chain of codes

International Nuclear Information System (INIS)

Notari, Carla; Grant, Carlos R.

2000-01-01

The purpose of the work was the evaluation of the the CAREM 25 reactor core, using a chain of codes (HUEMUL-PUMA-THERMIT) different to the one used in the original design (CONDOR-CITVAP-THERMIT). First, we performed a partial validation of the our codes in lattices similar to CAREM and reproduced a benchmark for simulation of gadolinium burnup. The results were considered satisfactory for this stage of the project. Then, we calculated the core along the normal operating equilibrium cycle and in hot and cold shut-down conditions. The main outcome of our evaluation confirms the general behaviour of the reference calculations except in one important point referring to the cold shut down. In this condition, the failure of one single rod of bank number 13 of the shut down system, leaves the core in a supercritical state at the beginning of the cycle and this anomaly persists during almost a third of the overall cycle. A new design of the core is proposed with minor modifications of the reference one, without introducing new types of fuel elements and keeping the same fuel management scheme. This new core fulfills all the design requirements. (author)

Simulation of TRAN B experiments by alumina thermite melt injection (SIMBATH out-of-pile experiments, TRAN simulation B1/1, B1/3, B1/4)

International Nuclear Information System (INIS)

Peppler, W.; Will, H.

1986-07-01

The SIMBATH programme was initiated to investigate the physical phenomena of transient material movement and relocation during transient overpower (TOP) and loss of flow (LOF) driven TOP accidents in LMFBR's. The energy release during the accident is simulated out of pile by the reaction of a thermite mixture. Within the frame of comparing studies of the behaviour of fuel (UO 2 ) and the thermite melt (Al 2 O 3 +Fe) used, respectively, the TRAN B series was reproduced out of pile with this thermite. Special emphasis is given to the similarities and differences in the freezing behaviour of these two materials. The test results of the simulation experiments are analysed and reported. Additionally the tests were recalculated with the code PLUGM. Similarity is found with respect to the freezing behaviour of these two materials. (orig.) [de

Analysis of the consequences of 'thermite' reaction; Analisis sobre las consecuencias de la reaccion 'termita'

Energy Technology Data Exchange (ETDEWEB)

Yorio, Daniel; Cincotta, Daniel O; Camacho, Esteban F; Bruno, Hernan R; Boero, Norma L [Comision Nacional de Energia Atomica, General San Martin (Argentina). Centro Atomico Constituyentes

1999-07-01

The mixture of Al-U{sub 3}O{sub 8} is not in a state of chemical equilibrium, and at temperatures of between 850 degree C and 1000 degree C, it reacts exo thermally. This is known, in corresponding bibliography, as a 'Thermite reaction'. This mixture is used in the manufacturing of the plate-type fuel used in research reactors. It has been pointed out that the release of energy caused by this type of reactions might represent a risk in case of accidents in this type of reactor. Conclusions, in general, tend to indicate that no such risk exists, although no concrete assurance is given that this is the case, and this fact, therefore, leaves room for doubt. The objective of this paper is to provide an in-depth study of what happens to a fuel plate when it is subjected to thermite reaction. We will, furthermore, analyze the consequences of the release of energy generated by this type of reaction within the core of the reactor, clearly defining the problem for this type of fuel and this kind of reactor.

Thermo-chemical characterization of a Al nanoparticle and NiO nanowire composite modified by Cu powder

International Nuclear Information System (INIS)

Bohlouli-Zanjani, Golnaz; Wen, John Z.; Hu, Anming; Persic, John; Ringuette, Sophie; Zhou, Y. Norman

2013-01-01

Highlights: • First study on the copper modified powder-type Al nanoparticle and NiO nanowire composites. • Experimental findings were unique in identifying the AlNi formation and comparing with the Al/CuO thermite. • Potential applications in material joining and bonding. - Abstract: Thermo-chemical properties of the Al nanoparticle and NiO nanowire composites modified by the micro-sized copper additive were investigated experimentally. Their onset temperatures of ignition and energy release data per mass were characterized using differential thermal analysis measurements. These microstructures and chemical compositions of reaction products were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The fuel-rich Al/NiO/Cu composites produced two types of metallic spheres. Copper spheres were formed from melting and solidification of the copper additive, while AlNi composite spheres were identified by the energy dispersive X-ray spectroscopy and X-ray diffraction analyses. It was found that the amount of the copper additive did not significantly influence the onset temperature of thermite peaks, but caused a dramatic change in energy release. The aforementioned ignition and energetic properties were compared with these from the Al nanoparticle and CuO nanowire composites

A DFT study on the enthalpies of thermite reactions and enthalpies of formation of metal composite oxide

Science.gov (United States)

Zhang, Yu-ying; Wang, Meng-jie; Chang, Chun-ran; Xu, Kang-zhen; Ma, Hai-xia; Zhao, Feng-qi

2018-05-01

The standard thermite reaction enthalpies (ΔrHmθ) for seven metal oxides were theoretically analyzed using density functional theory (DFT) under five different functional levels, and the results were compared with experimental values. Through the comparison of the linear fitting constants, mean error and root mean square error, the Perdew-Wang functional within the framework of local density approximation (LDA-PWC) and Perdew-Burke-Ernzerhof exchange-correlation functional within the framework of generalized gradient approximation (GGA-PBE) were selected to further calculate the thermite reaction enthalpies for metal composite oxides (MCOs). According to the Kirchhoff formula, the standard molar reaction enthalpies for these MCOs were obtained and their standard molar enthalpies of formation (ΔfHmθ) were finally calculated. The results indicated that GGA-PBE is the most suitable one out of the total five methods to calculate these oxides. Tungstate crystals present the maximum deviation of the enthalpies of thermite reactions for MCOs and these of their physical metal oxide mixtures, but ferrite crystals are the minimum. The correlation coefficients are all above 0.95, meaning linear fitting results are very precise. And the molar enthalpies of formation for NiMoO4, CuMoO4, PbZrO3 (Pm/3m), PbZrO3 (PBA2), PbZrO3 (PBam), MgZrO3, CdZrO3, MnZrO3, CuWO4 and Fe2WO6 were first obtained as -1078.75, -1058.45, -1343.87, -1266.54, -1342.29, -1333.03, -1210.43, -1388.05, -1131.07 and - 1860.11 kJ·mol-1, respectively.

Ignition dynamics and activation energies of metallic thermites: From nano- to micron-scale particulate composites

Science.gov (United States)

Hunt, Emily M.; Pantoya, Michelle L.

2005-08-01

Ignition behaviors associated with nano- and micron-scale particulate composite thermites were studied experimentally and modeled theoretically. The experimental analysis utilized a CO2 laser ignition apparatus to ignite the front surface of compacted nickel (Ni) and aluminum (Al) pellets at varying heating rates. Ignition delay time and ignition temperature as a function of both Ni and Al particle size were measured using high-speed imaging and microthermocouples. The apparent activation energy was determined from this data using a Kissinger isoconversion method. This study shows that the activation energy is significantly lower for nano- compared with micron-scale particulate media (i.e., as low as 17.4 compared with 162.5kJ /mol, respectively). Two separate Arrhenius-type mathematical models were developed that describe ignition in the nano- and the micron-composite thermites. The micron-composite model is based on a heat balance while the nanocomposite model incorporates the energy of phase transformation in the alumina shell theorized to be an initiating step in the solid-solid diffusion reaction and uniquely appreciable in nanoparticle media. These models were found to describe the ignition of the Ni /Al alloy for a wide range of heating rates.

Applications of the thermit code to 3D thermal hydraulic analysis of LWR cores

International Nuclear Information System (INIS)

Reed, W.H.

1979-01-01

The THERMIT code calculates the three-dimensional transient thermal hydraulic behavior of light water reactor cores. Its two-fluid dynamics equations for two-phase flow offer improved physical modelling capability needed in the context of calculation coupled to neutron kinetics for feedback. The numerical fluid dynamics method was chosen for reliability over a wider range of transients. An improved heat transfer numerical method is presented which gives better numerical stability and accuracy. A number of example calculations are discussed which give an idea of the power and flexibility of the code

Simulation of sodium boiling experiments with THERMIT sodium version

International Nuclear Information System (INIS)

Huh, K.Y.

1982-05-01

Natural and forced convection experiments (SBTF and French) are simulated with the sodium version of the thermal-hydraulic computer code THERMIT. Simulation is done for the test section with the pressure-velocity boundary condition and subsequently extended to the whole loop. For the test section simulation, a steady-state and transient calculations are performed and compared with experimental data. For the loop simulation, two methods are used, a simulated 1-D loop and an actual 1-D loop. In the simulated 1-D loop analysis, the vapor density is increased by one hundred and two hundred times to avoid the code failure and the results still showed some of the important characteristics of the two-phase flow oscillation in a loop. A mathematical model is suggested for the two-phase flow oscillation. In the actual 1-D loop, only the single phase calculation was performed and turned out to be nearly the same as the simulated 1-D loop single phase results

Study of the U3O8-Al thermite reaction and strength of reactor fuel tubes

International Nuclear Information System (INIS)

Peacock, H.B.

1984-01-01

Research and test reactors are presently operated with aluminum-clad fuel elements containing highly enriched uranium-aluminum alloy cores. To lower the enrichment and still maintain reactivity, the uranium content of the fuel element will need to be higher than currently achievable with alloy fuels. This will necessitate conversion to other forms such as U 3 O 8 -aluminum cermets. Above the aluminum melting point, U 3 O 8 and aluminum undergo an exothermic thermite reaction and cermet fuel cores tend to keep their original shape. Both factors could affect the course and consequences of a reactor accident, and therefore prompted an investigation of the behavior of cermet fuels at elevated temperatures. Tests were carried out using pellets and extruded tube sections with 53 wt % U 3 O 8 in aluminum. This content corresponds to a theoretical uranium density of 1.9 g/cc. Results indicate that the thermite reaction occurs at about 900 0 C in air without a violent effect. The heat of reaction was approximately 123 cal/g of U 3 O 8 -aluminum fuel. Tensile and compressive strength of the fuel tube section is low above 660 0 C. In tension, sections failed at about the aluminum melting point. In compression with 2 psi average axial stress, failure occurred at 917 0 C, while 7 psi average axial stress produced failure at 669 0 C. (author)

Study of the U3O8-Al thermite reaction and strength of reactor fuel tubes

International Nuclear Information System (INIS)

Peacock, H.B.

1983-01-01

Research and test reactors are presently operated with aluminum-clad fuel elements containing highly enriched uranium-aluminum alloy cores. To lower the enrichment and still maintain reactivity, the uranium content of the fuel element will need to be higher than currently achievable with alloy fuels. This will necessitate conversion to other forms such as U 3 O 8 -aluminum cermets. Above the aluminum melting point, U 3 O 8 and aluminum undergo an exothermic thermite reaction and cermet fuel cores tend to keep their original shape. Both factors could affect the course and consequences of a reactor accident, and prompted an investigation of the behavior of cermet fuels at elevated temperatures. Tests were carried out using pellets and extruded tube-sections with 53 wt % U 3 O 8 in aluminum. This content corresponds to a theoretical uranium density of 1.9 g/cc. Results indicate that the thermite reaction occurs at about 900 0 C in air without a violent effect. The heat of reaction was approximately 123 cal/g of U 3 O 8 -aluminum fuel. Tensile and compressive strength of the fuel tube section is low above 660 0 C. In tension, sections failed at about the aluminum melting point. In compression with 2-psi average axial stress, failure occurred at 917 0 C, while 7 psi average axial stress produced failure at 669 0 C

A new concept for very low energy detonators and torches

Energy Technology Data Exchange (ETDEWEB)

Bickes, Jr., R. W.; Grubelich, M. C.; Romero, J. A.; Staley, D. J.; Buss, R. J.; Ward, P. P.; Erickson, K. L.

1996-03-01

We deposited secondary explosive and multilayer thermite films directly onto semiconductor bridges (SCBs) and other substrates. Methods for the deposition of two thermite films (aluminum/copper oxide and magnesium/fluorocarbon polymer) were developed as part of this study and a new capability was obtained for depositing adherent films on any material, including Teflon and Gore-Tex. Our experimental program determined conditions for the SCB ignition of the deposited films, and with the aluminum/copper oxide film, we observed a lower threshold for ignition of a powder pressed against the bridge. We also looked at other ignition methods including lasers, spark discharges, primers and hot combustion gases.

Production of carbon nanotubes using mechanical milling in the presence of an exothermic reaction

International Nuclear Information System (INIS)

Karimi, E.Z.; Zebarjad, S.M.; Khaki, J. Vahdati; Izadi, H.

2010-01-01

Carbon nanotubes (CNTs) have shown promising potential for many applications in field of engineering due to their unusual significant properties. A major challenge for the industrial applications of CNTs is the large-quantity production. In this field, one new method for CNT production is annealing the ball milled graphite powder. The annealing process should be done in high temperature (1200-1400 o C) and needs time more than 6 h. The novel process introduced in this paper is elimination the annealing stage thorough a thermite reaction. The necessity heat for the conversion of milling products to CNTs was generated in the milling chamber by an exothermic reaction. In addition, the reaction products acted as catalysts to the CNT formation process. The adiabatic temperatures of 1809, 2000 and 2325 K were selected according to balancing graphite and thermite mixture (Aluminum + Iron oxide powders) for exothermic reaction. The results of thermo gravimetric analysis (TGA) test proved that CNT formation strongly depends on adiabatic temperature. The results of microscopic evaluation done by transition electron microscope (TEM) showed that at higher adiabatic temperature CNTs could be produced.

Experiments on the behaviour of thermite melt injected into sodium: Final report on the THINA test results

International Nuclear Information System (INIS)

Huber, F.; Kaiser, A.; Peppler, W.

1994-01-01

During hypothetical accidents of fast breeder reactors the core melts and part of the core material inventory is ejected into the upper coolant plenum. As a consequence, a fuel to coolant thermal interaction occurs between the melt and the sodium. A series of simulating experiments was carried out in KfK/IRS to improve the knowledge about the phenomenology of molten fuel/coolant interactions and to support theoretical work on the safety of fast breeder reactors. In the tests, a thermite melt of up to 3270 K is injected from below into a sodium pool the temperature of which is between 770 and 820 K. The masses of the melt and the sodium are about five and 150 kg, respectively. Thermal interactions have been observed to occur as a sequence of small local pressure events mainly during the melt injection. Large-scale vapour explosions have not been observed. Generally, the conversion ratios of thermal to mechanical energy have been low. (author)

In Situ Imaging of Particle Formation and Dynamics in Reactive Material Deflagrations

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Kyle T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-12-12

Reactive composites utilizing nanoparticles have been the topic of extensive research in the past two decades. The driver for this is that, as the particle size is decreased, the mixing scale between constituents is greatly reduced, which has long thought to increase the rate of chemical reaction. While a general trend of increased reactivity has been seen for metal / metal oxide, or thermite, reactive materials, some results have demonstrated diminishing returns as the particle size is further decreased. Recent results have shown that nanoparticles, which are typically aggregates of several primary particles, can undergo very rapid coalescence to form micron particles once a critical temperature is reached. Experiments on this topic to date have been performed on very small sample masses, and sometimes under vacuum; conditions which are not representative of the environment during a deflagration. In this feasibility study, a custom burn tube was used to ignite and react 100 mg powdered thermite samples in long acrylic tubes. X-ray imaging at APS Sector 32 was performed to image the particle field as a function of distance and time as the rarefied particle cloud expanded and flowed down the tube. Five different thermite formulations were investigated, Al / CuO, Al / Fe₂O₃, Al / SnO₂, Al / WO₃, and Al / Fe₂O₃, along with Al / CuO formulations with different sizes of Al particles ranging from 80 nm to approximate 10 μm. The results clearly show that the sample powder reacts and unloads into a distribution of larger micron-scale particles (~5-500 μm), which continue to react and propagate as the particle-laden stream flows down the tube. This was the first direct imaging of the particle field during a thermite deflagration, and gives significant insight into the evolution of reactants to products. Analysis of phase is currently being pursued to determine whether this method can be used to extract

Microstructure and wear resistance of Al2O3-M7C3/Fe composite coatings produced by laser controlled reactive synthesis

Science.gov (United States)

Tan, Hui; Luo, Zhen; Li, Yang; Yan, Fuyu; Duan, Rui

2015-05-01

Based on the principle of thermite reaction of Al and Fe2O3 powders, the Al2O3 ceramic reinforced Fe-based composite coatings were fabricated on a steel substrate by laser controlled reactive synthesis and cladding. The effects of different additions of thermite reactants on the phase transition, microstructure evolution, microhardness and wear resistance of the composite coatings were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Vickers microhardness and block-on-ring wear test, respectively. The results show that Al2O3 ceramic and M7C3 carbide are in situ synthesized via the laser controlled reactive synthesis. The Al2O3 ceramic and M7C3 carbides prefer to distribute along the γ-Fe phase boundary continuously, which separates the γ-Fe matrix and is beneficial to the grain refinement. With the increase of thermite reactants, the amount of Al2O3 ceramic and M7C3 carbide in the composite coatings increases gradually. Moreover the cladding layer changes from dendritic structure to columnar structure and martensite structure in the heat affected zone becomes coarse. The increased thermite reactants improve the microhardness and wear resistance of the in situ composite coatings obviously and enhance the hardness of the heat affected zone, which should be ascribed to the grain refinement, ceramic and carbide precipitation and solid solution strengthening.

Characteristics of Inconel Powders for Powder-Bed Additive Manufacturing

Directory of Open Access Journals (Sweden)

Quy Bau Nguyen

2017-10-01

Full Text Available In this study, the flow characteristics and behaviors of virgin and recycled Inconel powder for powder-bed additive manufacturing (AM were studied using different powder characterization techniques. The results revealed that the particle size distribution (PSD for the selective laser melting (SLM process is typically in the range from 15 μm to 63 μm. The flow rate of virgin Inconel powder is around 28 s·(50 g−1. In addition, the packing density was found to be 60%. The rheological test results indicate that the virgin powder has reasonably good flowability compared with the recycled powder. The inter-relation between the powder characteristics is discussed herein. A propeller was successfully printed using the powder. The results suggest that Inconel powder is suitable for AM and can be a good reference for researchers who attempt to produce AM powders.

Synthesis of Uranium nitride powders using metal uranium powders

International Nuclear Information System (INIS)

Yang, Jae Ho; Kim, Dong Joo; Oh, Jang Soo; Rhee, Young Woo; Kim, Jong Hun; Kim, Keon Sik

2012-01-01

Uranium nitride (UN) is a potential fuel material for advanced nuclear reactors because of their high fuel density, high thermal conductivity, high melting temperature, and considerable breeding capability in LWRs. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. The carbothermic reduction has an advantage in the production of fine powders. However it has many drawbacks such as an inevitable engagement of impurities, process burden, and difficulties in reusing of expensive N 15 gas. Manufacturing concerns issued in the carbothermic reduction process can be solved by changing the starting materials from oxide powder to metals. However, in nitriding process of metal, it is difficult to obtain fine nitride powders because metal uranium is usually fabricated in the form of bulk ingots. In this study, a simple reaction method was tested to fabricate uranium nitride powders directly from uranium metal powders. We fabricated uranium metal spherical powder and flake using a centrifugal atomization method. The nitride powders were obtained by thermal treating those metal particles under nitrogen containing gas. We investigated the phase and morphology evolutions of powders during the nitriding process. A phase analysis of nitride powders was also a part of the present work

New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

OpenAIRE

Budding, A.; Vaneker, T.H.J.

2013-01-01

In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of applications, but this study solely focuses on the application for powder -based three-dimensional printing (e.g. SLS, 3DP). This research is primarily interested in powder compaction for creating membrane...

Corrosion-resistant powder-metallurgy stainless steel powders and compacts therefrom

International Nuclear Information System (INIS)

Klar, E.; Ro, D.H.; Whitman, C.I.

1980-01-01

Disclosed is a process for improving the corrosion resistance of a stainless steel powder or compact thereof wherein the powder is produced by atomizing a melt of metals in an oxidizing environment whereby the resulting stainless steel powder is surface-enriched in silicon oxides. The process comprises adding an effective proportion of modifier metal to the melt prior to the atomization, the modifier metal selected from the group consisting of tin, aluminum, lead, zinc, magnesium, rare earth metals and like metals capable of enrichment about the surface of the resulting atomized stainless steel powder and effective under reductive sintering conditions in the depletion of the silicon oxides about the surface; and sintering the resulting atomized powder or a compact thereof under reducing conditions, the sintered powder or compact thereof being depleted in the silicon oxides and the corrosion resistance of the powder or compact thereof being improved thereby

Light extinction in metallic powder beds: Correlation with powder structure

International Nuclear Information System (INIS)

Rombouts, M.; Froyen, L.; Gusarov, A.V.; Bentefour, E.H.; Glorieux, C.

2005-01-01

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

Synthesis, Consolidation and Characterization of Sol-gel Derived Tantalum-Tungsten Oxide Thermite Composites

Energy Technology Data Exchange (ETDEWEB)

Cervantes, O [Univ. of California, Davis, CA (United States)

2010-06-01

Energetic composite powders consisting of sol-gel (SG) derived nanostructured tungsten oxide were produced with various amounts of micrometer-scale tantalum fuel metal. Such energetic composite powders were ignition-tested and results show that the powders are not sensitive to friction, spark and/or impact ignition. Initial consolidation experiments, using the High Pressure Spark Plasma Sintering (HPSPS) technique, on the SG derived nanostructured tungsten oxide produced samples with higher relative density than can be achieved with commercially available tungsten oxide. The SG derived nanostructured tungsten oxide with immobilized tantalum fuel metal (Ta - WO3) energetic composite was consolidated to a density of 9.17 g·cm-3 or 93% relative density. In addition, those samples were consolidated without significant pre-reaction of the constituents, thus retaining their stored chemical energy.

New Strategies for Powder Compaction in Powder-based Rapid Prototyping Techniques

NARCIS (Netherlands)

Budding, A.; Vaneker, Thomas H.J.

2013-01-01

In powder-based rapid prototyping techniques, powder compaction is used to create thin layers of fine powder that are locally bonded. By stacking these layers of locally bonded material, an object is made. The compaction of thin layers of powder mater ials is of interest for a wide range of

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.

Spherical rhenium metal powder

International Nuclear Information System (INIS)

Leonhardt, T.; Moore, N.; Hamister, M.

2001-01-01

The development of a high-density, spherical rhenium powder (SReP) possessing excellent flow characteristics has enabled the use of advanced processing techniques for the manufacture of rhenium components. The techniques that were investigated were vacuum plasma spraying (VPS), direct-hot isostatic pressing (D-HIP), and various other traditional powder metallurgy processing methods of forming rhenium powder into near-net shaped components. The principal disadvantages of standard rhenium metal powder (RMP) for advanced consolidation applications include: poor flow characteristics; high oxygen content; and low and varying packing densities. SReP will lower costs, reduce processing times, and improve yields when manufacturing powder metallurgy rhenium components. The results of the powder characterization of spherical rhenium powder and the consolidation of the SReP are further discussed. (author)

Measurement of loose powder density

International Nuclear Information System (INIS)

Akhtar, S.; Ali, A.; Haider, A.; Farooque, M.

2011-01-01

Powder metallurgy is a conventional technique for making engineering articles from powders. Main objective is to produce final products with the highest possible uniform density, which depends on the initial loose powder characteristics. Producing, handling, characterizing and compacting materials in loose powder form are part of the manufacturing processes. Density of loose metallic or ceramic powder is an important parameter for die design. Loose powder density is required for calculating the exact mass of powder to fill the die cavity for producing intended green density of the powder compact. To fulfill this requirement of powder metallurgical processing, a loose powder density meter as per ASTM standards is designed and fabricated for measurement of density. The density of free flowing metallic powders can be determined using Hall flow meter funnel and density cup of 25 cm/sup 3/ volume. Density of metal powders like cobalt, manganese, spherical bronze and pure iron is measured and results are obtained with 99.9% accuracy. (author)

Fundamentals of powder metallurgy

International Nuclear Information System (INIS)

Khan, I.H.; Qureshi, K.A.; Minhas, J.I.

1988-01-01

This book is being presented to introduce the fundamentals of technology of powder metallurgy. An attempt has been made to present an overall view of powder metallurgy technology in the first chapter, whereas chapter 2 to 8 deal with the production of metal powders. The basic commercial methods of powder production are briefly described with illustrations. Chapter 9 to 12 describes briefly metal powder characteristics and principles of testing, mixing, blending, conditioning, compaction and sintering. (orig./A.B.)

Microstructural and mechanical properties of titanium particulate reinforced magnesium composite materials

Energy Technology Data Exchange (ETDEWEB)

Umeda, Junko; Kawakami, Masashi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan); Kondoh, Katsuyoshi, E-mail: kondoh@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan); Ayman, El-Sayed; Imai, Hisashi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaragi, Osaka 567-0047 (Japan)

2010-10-01

Pure titanium (Ti) particulate reinforced pure magnesium (Mg) composite materials were fabricated via powder metallurgy route, and their microstructural and mechanical properties were evaluated. When using the elemental mixture of pure Mg and pure Ti powders and consolidating them by solid-state sintering process, no significant increase in tensile strength of the composites was obtained, because of poor bonding strength at the interface between {alpha}-Mg matrix and Ti particles. In particular, coarse magnesium oxide (MgO) particles of about 100 nm were formed via thermite reaction between TiO{sub 2} surface films of Ti particles and Mg raw powders and resulted in preventing the improvement of the mechanical properties of the composite material. On the other hand, when using the atomized pure Mg composite powders reinforced with Ti particulates, their extruded composite material showed obviously improved tensile strength and good elongation, compared to the extruded pure Mg powder material including no Ti particle. The obvious improvement in the tensile strength was due to the restriction of dislocation movement by Ti reinforcements under applied tensile load.

Low pressure powder injection moulding of stainless steel powders

Energy Technology Data Exchange (ETDEWEB)

Zampieron, J.V.; Soares, J.P.; Mathias, F.; Rossi, J.L. [Powder Processing Center CCP, Inst. de Pesquisas Energeticas e Nucleares, Sao Paulo, SP (Brazil); Filho, F.A. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

2001-07-01

Low-pressure powder injection moulding was used to obtain AISI 316L stainless steel parts. A rheological study was undertaken using gas-atomised powders and binders. The binders used were based on carnauba wax, paraffin, low density polyethylene and microcrystalline wax. The metal powders were characterised in terms of morphology, particle size distribution and specific surface area. These results were correlated to the rheological behaviour. The mixture was injected in the shape of square bar specimens to evaluate the performance of the injection process in the green state, and after sintering. The parameters such as injection pressure, viscosity and temperature were analysed for process optimisation. The binders were thermally removed in low vacuum with the assistance of alumina powders. Debinding and sintering were performed in a single step. This procedure shortened considerably the debinding and sintering time. (orig.)

Foundations of powder metallurgy

International Nuclear Information System (INIS)

Libenson, G.A.

1987-01-01

Consideration is being given to physicochemical foundations and technology of metal powders, moulding and sintering of bars, made of them or their mixtures with nonmetal powders. Data on he design of basic equipment used in the processes of powder metallurgy and its servicing are presented. General requirements of safety engineering when fabricating metal powders and products of them are mentioned

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.

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...

Biaxially textured articles formed by powder metallurgy

Science.gov (United States)

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

2003-08-05

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

An analysis of un-dissolved powders of instant powdered soup by using ultrasonographic image

Science.gov (United States)

Kawaai, Yukinori; Kato, Kunihito; Yamamoto, Kazuhiko; Kasamatsu, Chinatsu

2008-11-01

Nowadays, there are many instant powdered soups around us. When we make instant powdered soup, sometimes we cannot dissolve powders perfectly. Food manufacturers want to improve this problem in order to make better products. Therefore, they have to measure the state and volume of un-dissolved powders. Earlier methods for analyzing removed the un-dissolved powders from the container, the state of the un-dissolved power was changed. Our research using ultrasonographic image can measure the state of un-dissolved powders with no change by taking cross sections of the soup. We then make 3D soup model from these cross sections of soup. Therefore we can observe the inside of soup that we do not have ever seen. We construct accurate 3D model. We can visualize the state and volume of un-dissolved powders with analyzing the 3D soup models.

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.

Characterization of ceramic powder compacts

International Nuclear Information System (INIS)

Yanai, K.; Ishimoto, S.; Kubo, T.; Ito, K.; Ishikawa, T.; Hayashi, H.

1995-01-01

UO 2 and Al 2 O 3 powder packing structures in cylindrical powder compacts are observed by scanning electron microscopy using polished cross sections of compacts fixed by low viscosity epoxy resin. Hard aggregates which are not destroyed during powder compaction are observed in some of the UO 2 powder compacts. A technique to measure local density in powder compacts is developed based on counting characteristic X-ray intensity by energy dispersive X-ray analysis (EDX). The local density of the corner portion of the powder compact fabricated by double-acting dry press is higher than that of the inner portion. ((orig.))

Operation whey powder

International Nuclear Information System (INIS)

Brunner, E.

1987-01-01

The odyssey of the contaminated whey powder finally has come to an end, and the 5000 tonnes of whey now are designated for decontamination by means of an ion exchange technique. The article throws light upon the political and economic reasons that sent the whey powder off on a chaotic journey. It is worth mentioning in this context that the natural radioactivity of inorganic fertilizers is much higher than that of the whey powder in question. (HP) [de

Densification behavior of aluminum alloy powder mixed with zirconia powder inclusion under cold compaction

International Nuclear Information System (INIS)

Ryu, Hyun Seok; Lee, Sung Chul; Kim, Ki Tae

2002-01-01

Densification behavior of composite powders was investigated during cold compaction. Experimental data were obtained for aluminum alloy powder mixed with zirconia powder inclusion under triaxial compression. The cap model with constraint factors was implemented into a finite element program(ABAQUS) to simulate compaction responses of composite powders during cold compaction. Finite element results were compared with experimental data for densification behavior of composite powders under cold isostatic pressing and die compaction. The agreements between experimental data and finite element calculations from the cap model with constraint factors were good

Nuclear fuel powder transfer device

International Nuclear Information System (INIS)

Komono, Akira

1998-01-01

A pair of parallel rails are laid between a receiving portion to a molding portion of a nuclear fuel powder transfer device. The rails are disposed to the upper portion of a plurality of parallel support columns at the same height. A powder container is disposed while being tilted in the inside of the vessel main body of a transfer device, and rotational shafts equipped with wheels are secured to right and left external walls. A nuclear powder to be mixed, together with additives, is supplied to the powder container of the transfer device. The transfer device engaged with the rails on the receiving side is transferred toward the molding portion. The wheels are rotated along the rails, and the rotational shafts, the vessel main body and the powder container are rotated. The nuclear powder in the tilted powder container disposed is rotated right and left and up and down by the rotation, and the powder is mixed satisfactory when it reaches the molding portion. (I.N.)

Preparation of tris(8-hydroxyquinolinato)aluminum thin films by sputtering deposition using powder and pressed powder targets

Science.gov (United States)

Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Tanaka, Rei; Suda, Yoshiaki

2017-06-01

Tris(8-hydroxyquinolinato)aluminum (Alq3) thin films, for use in organic electroluminescence displays, were prepared by a sputtering deposition method using powder and pressed powder targets. Experimental results suggest that Alq3 thin films can be prepared using powder and pressed powder targets, although the films were amorphous. The surface color of the target after deposition became dark brown, and the Fourier transform infrared spectroscopy spectrum changed when using a pressed powder target. The deposition rate of the film using a powder target was higher than that using a pressed powder target. That may be because the electron and ion densities of the plasma generated using the powder target are higher than those when using pressed powder targets under the same deposition conditions. The properties of a thin film prepared using a powder target were almost the same as those of a film prepared using a pressed powder target.

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

Science.gov (United States)

Sun, Hongfang; Li, Zishanshan; Memon, Shazim Ali; Zhang, Qiwu; Wang, Yaocheng; Liu, Bing; Xu, Weiting; Xing, Feng

2015-09-17

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.

Application of laser in powder metallurgy

International Nuclear Information System (INIS)

Tolochko, N.K.

1995-01-01

Modern status of works in the field of laser application in powder metallurgy (powders preparation, sintering, coatings formation, powder materials processing) is considered. The attention is paid to the new promising direction in powder products shape-formation technology - laser layer-by-layer selective powders sintering and bulk sintering of packaged layered profiles produced by laser cutting of powder-based sheet blanks. 67 refs

Container for nuclear fuel powders

International Nuclear Information System (INIS)

Etheredge, B.F.; Larson, R.I.

1982-01-01

A critically safe container is disclosed for the storage and rapid discharge of enriched nuclear fuel material in powder form is disclosed. The container has a hollow, slab-shaped container body that has one critically safe dimension. A powder inlet is provided on one side wall of the body adjacent to a corner thereof and a powder discharge port is provided at another corner of the body approximately diagonal the powder inlet. Gas plenum for moving the powder during discharge are located along the side walls of the container adjacent the discharge port

Preparation of superconductor precursor powders

Science.gov (United States)

Bhattacharya, Raghunath

1998-01-01

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

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.

Magnetically responsive enzyme powders

Energy Technology Data Exchange (ETDEWEB)

Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

2015-04-15

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

Sintered aluminium powders

International Nuclear Information System (INIS)

Stepanova, M.G.; Matveev, B.I.

1974-01-01

The mechanical and physical properties of aluminium powder alloys and the various methods employed to produce them are considered. Data are given on the hardening of the alloys SAP and SPAK-4, as well as the powder-alloy system Al-Cr-Zr. (L.M.)

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.

Powder diffraction

International Nuclear Information System (INIS)

Hart, M.

1995-01-01

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

Method to blend separator powders

Science.gov (United States)

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

2007-12-04

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

Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

International Nuclear Information System (INIS)

Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

1979-01-01

Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

SAF line powder operations

International Nuclear Information System (INIS)

Frederickson, J.R.; Horgos, R.M.

1983-10-01

An automated nuclear fuel fabrication line is being designed for installation in the Fuels and Materials Examination Facility (FMEF) near Richland, Washington. The fabrication line will consist of seven major process systems: Receiving and Powder Preparation; Powder Conditioning; Pressing and Boat Loading; Debinding, Sintering, and Property Adjustment; Boat Transport; Pellet Inspection and Finishing; and Pin Operations. Fuel powder processing through pellet pressing will be discussed in this paper

Two layer powder pressing

International Nuclear Information System (INIS)

Schreiner, H.

1979-01-01

First, significance and advantages of sintered materials consisting of two layers are pointed out. By means of the two layer powder pressing technique metal powders are formed resulting in compacts with high accuracy of shape and mass. Attributes of basic powders, different filling methods and pressing techniques are discussed. The described technique is supposed to find further applications in the field of two layer compacts in the near future

The analysis of powder diffraction data

International Nuclear Information System (INIS)

David, W.I.F.; Harrison, W.T.A.

1986-01-01

The paper reviews neutron powder diffraction data analysis, with emphasis on the structural aspects of powder diffraction and the future possibilities afforded by the latest generation of very high resolution neutron and x-ray powder diffractometers. Traditional x-ray powder diffraction techniques are outlined. Structural studies by powder diffraction are discussed with respect to the Rietveld method, and a case study in the Rietveld refinement method and developments of the Rietveld method are described. Finally studies using high resolution powder diffraction at the Spallation Neutron Source, ISIS at the Rutherford Appleton Laboratory are summarized. (U.K.)

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.

Black powder in gas pipelines

Energy Technology Data Exchange (ETDEWEB)

Sherik, Abdelmounam [Saudi Aramco, Dhahran (Saudi Arabia)

2009-07-01

Despite its common occurrence in the gas industry, black powder is a problem that is not well understood across the industry, in terms of its chemical and physical properties, source, formation, prevention or management of its impacts. In order to prevent or effectively manage the impacts of black powder, it is essential to have knowledge of its chemical and physical properties, formation mechanisms and sources. The present paper is divided into three parts. The first part of this paper is a synopsis of published literature. The second part reviews the recent laboratory and field work conducted at Saudi Aramco Research and Development Center to determine the compositions, properties, sources and formation mechanisms of black powder in gas transmission systems. Microhardness, nano-indentation, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscopy (SEM) techniques were used to analyze a large number of black powder samples collected from the field. Our findings showed that black powder is generated inside pipelines due to internal corrosion and that the composition of black powder is dependent on the composition of transported gas. The final part presents a summary and brief discussion of various black powder management methods. (author)

Fabrication of Cu-riched W–Cu composites by combustion synthesis and melt-infiltration in ultrahigh-gravity field

Energy Technology Data Exchange (ETDEWEB)

Zhao, Pei [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Guo, Shibin; Liu, Guanghua; Chen, Yixiang [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Li, Jiangtao, E-mail: ljt0012@vip.sina.com [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

2013-10-15

Unadulterated Cu-riched W–Cu composites of W27–Cu73, W34–Cu66, W40–Cu60, W49–Cu51 and W56–Cu44 have been prepared by a novel method called combustion synthesis and melt-infiltration in ultrahigh-gravity field, of which W27–Cu73 and W34–Cu66 showed good ductility and W40–Cu60, W49–Cu51 and W56–Cu44 were brittle. In this technique, Cu melt accompanied with a great amount of heat was produced by thermit reaction and infiltrated into W–Cu powder bed. When the powder bed was Cu-riched powder bed such as W50–Cu50 or W60–Cu40, Cu melt would go through the powder bed, reach the bottom of the graphite crucible and then form a heat dissipation channel. Thus the cooling rate was so fast that the product was mixed up with impurity. The problem can be solved by putting some W powders under W50–Cu50 or W60–Cu40 powder bed to prevent the formation of heat dissipation channel.

Thermal plasma spheroidization and spray deposition of barium titanate powder and characterization of the plasma sprayable powder

Energy Technology Data Exchange (ETDEWEB)

Pakseresht, A.H., E-mail: amirh_pak@yahoo.com [Department of Ceramics, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Rahimipour, M.R. [Department of Ceramics, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Vaezi, M.R. [Department of Nanotechnology and Advanced Materials, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Salehi, M. [Department of Materials Engineering, Isfahan University of Technology, P.O. Box 84156-83111, Isfahan (Iran, Islamic Republic of)

2016-04-15

In this paper, atmospheric plasma spray method was used to produce dense plasma sprayable powder and thick barium titanate film. In this regard, the commercially feedstock powders were granulated and spheroidized by the organic binder and the thermal spray process, respectively. Scanning electron microscopy was used to investigate the microstructure of the produced powders and the final deposits. X-ray diffraction was also implemented to characterize phase of the sprayed powder. The results indicated that spheroidized powder had suitable flowability as well as high density. The micro-hardness of the film produced by the sprayed powders was higher than that of the film deposited by the irregular granules. Additionally, relative permittivity of the films was increased by decreasing the defects from 160 to 293 for film deposited using spheroidized powder. The reduction in the relative permittivity of deposits, in comparison with the bulk material, was due to the existence of common defects in the thermal spray process. - Highlights: • We prepare sprayable BaTiO{sub 3} powder with no or less inside voids for plasma spray application for first time. • The sprayable powder has good flow characteristics and high density. • Powder spheroidization via plasma spray improves the hardness and dielectric properties of the deposited film.

Thermal plasma spheroidization and spray deposition of barium titanate powder and characterization of the plasma sprayable powder

International Nuclear Information System (INIS)

Pakseresht, A.H.; Rahimipour, M.R.; Vaezi, M.R.; Salehi, M.

2016-01-01

In this paper, atmospheric plasma spray method was used to produce dense plasma sprayable powder and thick barium titanate film. In this regard, the commercially feedstock powders were granulated and spheroidized by the organic binder and the thermal spray process, respectively. Scanning electron microscopy was used to investigate the microstructure of the produced powders and the final deposits. X-ray diffraction was also implemented to characterize phase of the sprayed powder. The results indicated that spheroidized powder had suitable flowability as well as high density. The micro-hardness of the film produced by the sprayed powders was higher than that of the film deposited by the irregular granules. Additionally, relative permittivity of the films was increased by decreasing the defects from 160 to 293 for film deposited using spheroidized powder. The reduction in the relative permittivity of deposits, in comparison with the bulk material, was due to the existence of common defects in the thermal spray process. - Highlights: • We prepare sprayable BaTiO_3 powder with no or less inside voids for plasma spray application for first time. • The sprayable powder has good flow characteristics and high density. • Powder spheroidization via plasma spray improves the hardness and dielectric properties of the deposited film.

Weighing fluidized powder

International Nuclear Information System (INIS)

Adomitis, J.T.; Larson, R.I.

1980-01-01

Fluidized powder is discharged from a fluidizing vessel into a container. Accurate metering is achieved by opening and closing the valve to discharge the powder in a series of short-duration periods until a predetermined weight is measured by a load cell. The duration of the discharge period may be increased in inverse proportion to the amount of powder in the vessel. Preferably the container is weighed between the discharge periods to prevent fluctuations resulting from dynamic effects. The gas discharged into the container causes the pressures in the vessel and container to equalize thereby decreasing the rate of discharge and increasing the accuracy of metering as the weight reaches the predetermined value. (author)

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... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1647 Copper powder. (a) Identity. (1) The color additive copper powder is a very fine free-flowing metallic powder prepared from virgin electrolytic copper. It...

[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.

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

Crushing method for nuclear fuel powder

International Nuclear Information System (INIS)

Hasegawa, Shin-ichi; Tsuchiya, Haruo.

1997-01-01

A crushing medium is contained in mill pots disposed at the circumferential periphery of a main axis. The diameter of each mill pot is determined such that powdery nuclear fuels containing aggregated powders and ground and mixed powders do not reach criticality. A plurality of mill pots are revolved in the direction of the main axis while each pots rotating on its axis. Powdery nuclear fuels containing aggregated powders are conveyed to a supply portion of the moll pot, and an inert gas is supplied to the supply portion. The powdery nuclear fuels are supplied from the supply portion to the inside of the mill pots, and the powdery nuclear fuels containing aggregated powders are crushed by centrifugal force caused by the rotation and the revolving of the mill pots by means of the crushing medium. UO 2 powder in uranium oxide fuels can be crushed continuously. PuO 2 powder and UO 2 powder in MOX fuels can be crushed and mixed continuously. (I.N.)

Ultrafine hydrogen storage powders

Science.gov (United States)

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

2000-06-13

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

Electrochemical behaviors of wax-coated Li powder/Li 4Ti 5O 12 cells

Science.gov (United States)

Park, Han Eol; Seong, Il Won; Yoon, Woo Young

The wax-coated Li powder specimen was effectively synthesized using the drop emulsion technique (DET). The wax layer on the powder was verified by SEM, Focused Ion Beam (FIB), EDX and XPS. The porosity of a sintered wax-coated Li electrode was measured by linear sweep voltammetry (LSV) and compared with that of a bare, i.e., un-coated Li electrode. The electrochemical behavior of the wax-coated Li powder anode cell was examined by the impedance analysis and cyclic testing methods. The cyclic behavior of the wax-coated Li powder anode with the Li 4Ti 5O 12 (LTO) cathode cell was examined at a constant current density of 0.35 mA cm -2 with the cut-off voltages of 1.2-2.0 V at 25 °C. Over 90% of the initial capacity of the cell remained even after the 300th cycle. The wax-coated Li powder was confirmed to be a stable anode material.

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.

Plasma technology for powder particles

Energy Technology Data Exchange (ETDEWEB)

Kranz, E. (Technische Hochschule, Ilmenau (German Democratic Republic))

1983-03-01

A survey is given of principles and applications of plasma spraying and of powder transformation and generation in plasma considering spheroidization, grain size transformation, powder particle formation, powder reduction, and melting within the power range of 10/sup 3/ to 10/sup 7/ W. The products are applied in many industrial fields such as nuclear engineering, hard metal production, metallurgy, catalysis, and semiconductor techniques.

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.

Minimum ignition energy of nano and micro Ti powder in the presence of inert nano TiO₂ powder.

Science.gov (United States)

Chunmiao, Yuan; Amyotte, Paul R; Hossain, Md Nur; Li, Chang

2014-06-15

The inerting effect of nano-sized TiO2 powder on ignition sensitivity of nano and micro Ti powders was investigated with a Mike 3 apparatus. "A little is not good enough" is also suitable for micro Ti powders mixed with nano-sized solid inertants. MIE of the mixtures did not significantly increase until the TiO2 percentage exceeded 50%. Nano-sized TiO2 powders were ineffective as an inertant when mixed with nano Ti powders, especially at higher dust loadings. Even with 90% nano TiO2 powder, mixtures still showed high ignition sensitivity because the statistic energy was as low as 2.1 mJ. Layer fires induced by ignited but unburned metal particles may occur for micro Ti powders mixed with nano TiO2 powders following a low level dust explosion. Such layer fires could lead to a violent dust explosion after a second dispersion. Thus, additional attention is needed to prevent metallic layer fires even where electric spark potential is low. In the case of nano Ti powder, no layer fires were observed because of less flammable material involved in the mixtures investigated, and faster flame propagation in nanoparticle clouds. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultrasonic wave propagation in powders

Science.gov (United States)

Al-Lashi, R. S.; Povey, M. J. W.; Watson, N. J.

2018-05-01

Powder clumps (cakes) has a significant effect on the flowability and stability of powders. Powder caking is mainly caused by moisture migration due to wetting and environmental (temperature and humidity) changes. The process of moisture migration caking involves creating liquid bridges between the particles during condensation which subsequently harden to form solid bridges. Therefore, an effective and reliable technique is required to quantitatively and non-invasively monitor caking kinetics and effective stiffness. This paper describes two ultrasonic instruments (ultrasonic velocity pulse and airborne ultrasound systems) that have been used to monitor the caking phenomenon. Also, it discusses the relationship between the ultrasonic velocity and attenuation measurements and tracking caking kinetics and the effective stiffness of powders.

Effect of surface energy on powder compactibility.

Science.gov (United States)

Fichtner, Frauke; Mahlin, Denny; Welch, Ken; Gaisford, Simon; Alderborn, Göran

2008-12-01

The influence of surface energy on the compactibility of lactose particles has been investigated. Three powders were prepared by spray drying lactose solutions without or with low proportions of the surfactant polysorbate 80. Various powder and tablet characterisation procedures were applied. The surface energy of the powders was characterized by Inverse Gas Chromatography and the compressibility of the powders was described by the relationship between tablet porosity and compression pressure. The compactibility of the powders was analyzed by studying the evolution of tablet tensile strength with increasing compaction pressure and porosity. All powders were amorphous and similar in particle size, shape, and surface area. The compressibility of the powders and the microstructure of the formed tablets were equal. However, the compactibility and dispersive surface energy was dependent of the composition of the powders. The decrease in tablet strength correlated to the decrease in powder surface energy at constant tablet porosities. This supports the idea that tablet strength is controlled by formation of intermolecular forces over the areas of contact between the particles and that the strength of these bonding forces is controlled by surface energy which, in turn, can be altered by the presence of surfactants.

Safety consideration when handling metal powders

CSIR Research Space (South Africa)

Benson, JM

2012-03-01

Full Text Available to some form of irritation or allergic reaction (e.g. dermatitis). In the case of nano-powders, the particles can penetrate the skin and become absorbed into cells in various parts of the body, including the brain � Eye contact, resulting in a... powders, and thus data is often limited to various ailments that have been reported for people working with that particular powder (amongs other things). There are three ways that powders can interact with the body: � Skin contact, which may lead...

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.

Baking Powder Wars

OpenAIRE

Civitello, Linda

2017-01-01

How did a mid-nineteenth century American invention, baking powder, replace yeast as a leavening agent and create a culinary revolution as profound as the use of yeast thousands of years ago?The approach was two-pronged and gendered: business archives, U.S. government records and lawsuits revealed how baking powder was created, marketed, and regulated. Women’s diaries and cookbooks—personal, corporate, community, ethnic—from the eighteenth century to internet blogs showed the use women made o...

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.

Comparison of blueberry powder produced via foam-mat freeze-drying versus spray-drying: evaluation of foam and powder properties.

Science.gov (United States)

Darniadi, Sandi; Ho, Peter; Murray, Brent S

2018-03-01

Blueberry juice powder was developed via foam-mat freeze-drying (FMFD) and spray-drying (SD) via addition of maltodextrin (MD) and whey protein isolate (WPI) at weight ratios of MD/WPI = 0.4 to 3.2 (with a fixed solids content of 5 wt% for FMFD and 10 wt% for SD). Feed rates of 180 and 360 mL h -1 were tested in SD. The objective was to evaluate the effect of the drying methods and carrier agents on the physical properties of the corresponding blueberry powders and reconstituted products. Ratios of MD/WPI = 0.4, 1.0 and 1.6 produced highly stable foams most suitable for FMFD. FMFD gave high yields and low bulk density powders with flake-like particles of large size that were also dark purple with high red values. SD gave low powder recoveries. The powders had higher bulk density and faster rehydration times, consisting of smooth, spherical and smaller particles than in FMFD powders. The SD powders were bright purple but less red than FMFD powders. Solubility was greater than 95% for both FMFD and SD powders. The FMFD method is a feasible method of producing blueberry juice powder and gives products retaining more characteristics of the original juice than SD. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

[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.

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...

CLAY SOIL STABILISATION USING POWDERED GLASS

Directory of Open Access Journals (Sweden)

J. OLUFOWOBI

2014-10-01

Full Text Available This paper assesses the stabilizing effect of powdered glass on clay soil. Broken waste glass was collected and ground into powder form suitable for addition to the clay soil in varying proportions namely 1%, 2%, 5%, 10% and 15% along with 15% cement (base by weight of the soil sample throughout. Consequently, the moisture content, specific gravity, particle size distribution and Atterberg limits tests were carried out to classify the soil using the ASSHTO classification system. Based on the results, the soil sample obtained corresponded to Group A-6 soils identified as ‘fair to poor’ soil type in terms of use as drainage and subgrade material. This justified stabilisation of the soil. Thereafter, compaction, California bearing ratio (CBR and direct shear tests were carried out on the soil with and without the addition of the powdered glass. The results showed improvement in the maximum dry density values on addition of the powdered glass and with corresponding gradual increase up to 5% glass powder content after which it started to decrease at 10% and 15% powdered glass content. The highest CBR values of 14.90% and 112.91% were obtained at 5% glass powder content and 5mm penetration for both the unsoaked and soaked treated samples respectively. The maximum cohesion and angle of internal friction values of 17.0 and 15.0 respectively were obtained at 10% glass powder content.

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.

Shock diffraction in alumina powder

International Nuclear Information System (INIS)

Venz, G.; Killen, P.D.; Page, N.W.

1996-01-01

In order to produce complex shaped components by dynamic compaction of ceramic powders detailed knowledge of their response under shock loading conditions is required. This work attempts to provide data on release effects and shock attenuation in 1 μm and 5 μm α-alumina powders which were compacted to between 85 % and 95 % of the solid phase density by the impact of high velocity steel projectiles. As in previous work, the powder was loaded into large cylindrical dies with horizontal marker layers of a contrasting coloured powder to provide a record of powder displacement in the recovered specimens. After recovery and infiltration with a thermosetting resin the specimens were sectioned and polished to reveal the structure formed by the passage of the projectile and shock wave. Results indicate that the shock pressures generated were of the order of 0.5 to 1.4 GPa and higher, with shock velocities and sound speeds in the ranges 650 to 800 m/s and 350 to 400 m/s respectively

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...

21 CFR 73.2647 - Copper powder.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Copper powder. 73.2647 Section 73.2647 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2647 Copper powder. (a) Identity and specifications. The color additive copper powder shall conform in identity and specifications to the requirements of § 73...

Effect of additives on the orientation of magnetic Sr-ferrite powders in powder injection molded compacts

Energy Technology Data Exchange (ETDEWEB)

Cho, T.S. [Sangju National Unviersity, Sangju (Korea); Jeung, W.Y. [Korea Institute of Science and Technology, Seoul (Korea)

2001-03-01

The effect of additives on the orientation of magnetic Sr-ferrite powders has been studied during powder injection molding under applied magnetic field for fabricating multi=pole anisotropic sintered Sr-ferrite magnets. The orientation of the Sr-ferrite powders depends sensitively on the fluidity of powder-binder mixture, related to the binder additives and the injection molding temperature, and the magnetic field intensity. The orientation of Sr-ferrite powders is good for the compacts with stearic acid added in the binder system of paraffin wax/ carnauba wax/HDPE, but it is poor of the compacts with silane coupling agent added. The orientation of sr-ferrites higher than 80% is achieved at the following useful conditions; apparent viscosity lower than 2500 poise in 1000 sec {sup -1} shear rate and applied magnetic field higher than 4 kOe. (author). 15 refs., 1 tab., 6 figs.

Hydrothermal treatment of coprecipitated YSZ powders

International Nuclear Information System (INIS)

Arakaki, Alexander Rodrigo; Yoshito, Walter Kenji; Ussui, Valter; Lazar, Dolores Ribeiro Ricci

2009-01-01

Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermally treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, uniaxially pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N 2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density. (author)

Cheese powder as an ingredient in emulsion sausages

DEFF Research Database (Denmark)

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

2017-01-01

Different types of cheese powder were added to meat emulsion sausages in order to address its influence on chemical composition, volatile compounds profile and sensory properties, and its potential to reduce salt content through boosting saltiness. Addition of cheese powder to emulsion sausages...... 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...

Spheroidization of glass powders for glass ionomer cements.

Science.gov (United States)

Gu, Y W; Yap, A U J; Cheang, P; Kumar, R

2004-08-01

Commercial angular glass powders were spheroidized using both the flame spraying and inductively coupled radio frequency plasma spraying techniques. Spherical powders with different particle size distributions were obtained after spheroidization. The effects of spherical glass powders on the mechanical properties of glass ionomer cements (GICs) were investigated. Results showed that the particle size distribution of the glass powders had a significant influence on the mechanical properties of GICs. Powders with a bimodal particle size distribution ensured a high packing density of glass ionomer cements, giving relatively high mechanical properties of GICs. GICs prepared by flame-spheroidized powders showed low strength values due to the loss of fine particles during flame spraying, leading to a low packing density and few metal ions reacting with polyacrylic acid to form cross-linking. GICs prepared by the nano-sized powders showed low strength because of the low bulk density of the nano-sized powders and hence low powder/liquid ratio of GICs.

Effect of powder geometry on densification

International Nuclear Information System (INIS)

Spasskij, M.R.; Spasskaya, I.A.; Shatalova, I.G.; Shchukin, E.D.

1979-01-01

The effect of particle shape and size composition on the processes of powder vibratory compacting is considered. Using microstress measurements in compacted structures of conglomerated and disintegrated tungsten powders as well as powder strength testing the existence of a zone of transition from a structural deformation to a plastic one has been shown. The formation of phase interparticle contacts of practically stable strength (approximately 5-6 dyn) is a characteristic feature of the zone. The width of the transition zone greatly depends upon geometrical powder properties; 55-65 % for conglomerated tungsten, 63-66 % for integrated tungsten

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.

Simple process to fabricate nitride alloy powders

International Nuclear Information System (INIS)

Yang, Jae Ho; Kim, Dong-Joo; Kim, Keon Sik; Rhee, Young Woo; Oh, Jang-Soo; Kim, Jong Hun; Koo, Yang Hyun

2013-01-01

Uranium mono-nitride (UN) is considered as a fuel material [1] for accident-tolerant fuel to compensate for the loss of fissile fuel material caused by adopting a thickened cladding such as SiC composites. Uranium nitride powders can be fabricated by a carbothermic reduction of the oxide powders, or the nitriding of metal uranium. Among them, a direct nitriding process of metal is more attractive because it has advantages in the mass production of high-purity powders and the reusing of expensive 15 N 2 gas. However, since metal uranium is usually fabricated in the form of bulk ingots, it has a drawback in the fabrication of fine powders. The Korea Atomic Energy Research Institute (KAERI) has a centrifugal atomisation technique to fabricate uranium and uranium alloy powders. In this study, a simple reaction method was tested to fabricate nitride fuel powders directly from uranium metal alloy powders. Spherical powder and flake of uranium metal alloys were fabricated using a centrifugal atomisation method. The nitride powders were obtained by thermal treating the metal particles under nitrogen containing gas. The phase and morphology evolutions of powders were investigated during the nitriding process. A phase analysis of nitride powders was also part of the present work. KAERI has developed the centrifugal rotating disk atomisation process to fabricate spherical uranium metal alloy powders which are used as advanced fuel materials for research reactors. The rotating disk atomisation system involves the tasks of melting, atomising, and collecting. A nozzle in the bottom of melting crucible introduces melt at the center of a spinning disk. The centrifugal force carries the melt to the edge of the disk and throws the melt off the edge. Size and shape of droplets can be controlled by changing the nozzle size, the disk diameter and disk speed independently or simultaneously. By adjusting the processing parameters of the centrifugal atomiser, a spherical and flake shape

MECHANICS OF DYNAMIC POWDER COMPACTION PROCESS

OpenAIRE

Nurettin YAVUZ

1996-01-01

In recent years, interest in dynamic compaction methods of metal powders has increased due to the need to improve compaction properties and to increase production rates of compacts. In this paper, review of dynamic and explosive compaction of metal powders are given. An attempt is made to get a better understanding of the compaction process with the mechanicis of powder compaction.

Tantalum powder consolidation, modeling and properties

International Nuclear Information System (INIS)

Bingert, S.R.; Vargas, V.D.; Sheinberg, H.C.

1996-01-01

A systematic approach was taken to investigate the consolidation of tantalum powders. The effects of sinter time, temperature and ramp rate; hot isostatic pressing (HIP) temperature and time; and powder oxygen content on consolidation density, kinetics, microstructure, crystallographic texture, and mechanical properties have been evaluated. In general, higher temperatures and longer hold times resulted in higher density compacts with larger grain sizes for both sintering and HIP'ing. HIP'ed compacts were consistently higher in density than sintered products. The higher oxygen content powders resulted in finer grained, higher density HIP'ed products than the low oxygen powders. Texture analysis showed that the isostatically processed powder products demonstrated a near random texture. This resulted in isotropic properties in the final product. Mechanical testing results showed that the HIP'ed powder products had consistently higher flow stresses than conventionally produced plates, and the sintered compacts were comparable to the plate material. A micromechanics model (Ashby HIP model) has been employed to predict the mechanisms active in the consolidation processes of cold isostatic pressing (CIP), HIP and sintering. This model also predicts the density of the end product and whether grain growth should be expected under the applied processing conditions

Vacuum hot pressing of titanium-alloy powders

International Nuclear Information System (INIS)

Malik, R.K.

1975-01-01

Full or nearly full dense products of wrought-metal properties have been obtained by vacuum hot pressing (VHP) of several prealloyed Ti--6Al--4V powders including hydride, hydride/dehydride, and rotating electrode process (REP) spherical powder. The properties of billets VHP from Ti--6Al--4V hydride powder and from hydride/dehydride powders have been shown to be equivalent. The REP spherical powder billets processed by VHP or by hot isostatic pressing (HIP) resulted in equivalent tensile properties. The potential of VHP for fabrication of near net aircraft parts such as complex fittings and engine disks offers considerable cost savings due to reduced material and machining requirements

Superconductors by powder metallurgy techniques

International Nuclear Information System (INIS)

Pickus, M.R.; Wang, J.L.F.

1976-05-01

Fabrication methods for Nb 3 Sn type compounds are described. Information is included on the Bell Telephone process, the General Electric tape process, superconductor stability, the bronze process, powder metallurgy multifilamentary tapes and wires, and current assessment of powder metallurgy superconducting wire

Impact strength of sintered astaloy CrM powders

International Nuclear Information System (INIS)

Kazior, J.; Ploszczak, J.; Nykiel, M.; Pieczonka, T.

2003-01-01

In this paper results of a series of impact tests on sintered Astaloy CrM powders alloys modified by boron are presented and discussed. Boron in different forms, i.e. as elemental boron powder, boron carbide B 4 C powder or mixture of boron and carbon elemental powders, was used in different weight percentage to activate sintering of Astaloy CrM powder and to increase hardenability, with aim of increasing impact strength in view of structural applications. (author)

Shock compaction of molybdenum powder

Science.gov (United States)

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

1983-01-01

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

Metal powder production by gas atomization

Science.gov (United States)

Ting, E. Y.; Grant, N. J.

1986-01-01

The confined liquid, gas-atomization process was investigated. Results from a two-dimensional water model showed the importance of atomization pressure, as well as delivery tube and atomizer design. The atomization process at the tip of the delivery tube was photographed. Results from the atomization of a modified 7075 aluminum alloy yielded up to 60 wt pct. powders that were finer than 45 microns in diameter. Two different atomizer designs were evaluated. The amount of fine powders produced was correlated to a calculated gas-power term. An optimal gas-power value existed for maximized fine powder production. Atomization at gas-power greater than or less than this optimal value produced coarser powders.

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.

Metallography of powder metallurgy materials

International Nuclear Information System (INIS)

Lawley, Alan; Murphy, Thomas F.

2003-01-01

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

Spheroidization of molybdenum powder by radio frequency thermal plasma

Science.gov (United States)

Liu, Xiao-ping; Wang, Kuai-she; Hu, Ping; Chen, Qiang; Volinsky, Alex A.

2015-11-01

To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency (RF) plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 µm, and the tap density is increased from 2.7 to 6.2 g/cm3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.

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....

Powder handling for automated fuel processing

International Nuclear Information System (INIS)

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

1989-01-01

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

Development of granular powder manufacturing technology by spray pyrolysis

International Nuclear Information System (INIS)

Katoh, Yoshiyuki; Kawase, Keiichi; Takahashi, Yoshiharu; Todokoro, Akio

1996-01-01

For shortening of mixed-oxide (MOX) fuel manufacturing process and improvement in treatment of MOX-powder, we have been developing the granular powder production technology. Since the granular powders have excellent fluidity owing to the spherical shape, there is the possibility of modifying scattering and adcering of the powder in the process equipment. In this paper, spray pyrolysis process in adopted as the process of manufacturing the granular powders and the basic feasibility study has been carried out. The experimental results show that the manufactured granular powders have excellent fluidity and the diameter of the powders is controllable. Furthermore, high density pellets are formed by sintering the powders. Thus, it is clarified that this process is promising for the actual MOX fuel fabrication. (author)

Vibration-Assisted Handling of Dry Fine Powders

Directory of Open Access Journals (Sweden)

Paul Dunst

2018-04-01

Full Text Available Since fine powders tend strongly to adhesion and agglomeration, their processing with conventional methods is difficult or impossible. Typically, in order to enable the handling of fine powders, chemicals are added to increase the flowability and reduce adhesion. This contribution shows that instead of additives also vibrations can be used to increase the flowability, to reduce adhesion and cohesion, and thus to enable or improve processes such as precision dosing, mixing, and transport of very fine powders. The methods for manipulating powder properties are described in detail and prototypes for experimental studies are presented. It is shown that the handling of fine powders can be improved by using low-frequency, high-frequency or a combination of low- and high-frequency vibration.

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...... normal stress were approximately 200Pa and 114Pa, 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 500Pa and 200Pa, 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...

Fabrication of nuclear fuel by powder injection moulding: Study of the binders systems and the de-binding of feedstock containing actinide powder

International Nuclear Information System (INIS)

Bricout, J.

2012-01-01

Powder Injection Moulding (PIM) is identified as an innovative process for the nuclear fuel fabrication. Technological breakthrough compared to the current process of powder metallurgy, the impact of actinide powder's specificities on the different steps of PIM is performed. Alumina powders simulating actinide powder have been implemented with a reference binders system. Thermal and rheological studies show the injectability and the de-binding of feedstocks with adequate solid loading (≥50 %vol), thanks to the de-agglomeration during the mixing step, which allow to obtain net shape fuel pellet. Specific surface area of powders, acting as a key role in behaviour's feedstocks, has been integrated in analysis models of viscosity prediction according to the shear rate. Also conducted studies on uranium oxide powder show that the selected binders systems, which have a compatible rheological behaviour with PIM process, impact the de-agglomeration of powder and final microstructure of the fuel pellet, consistent with the results obtained on alumina powders. Independent behaviour of binders and uranium oxide powder, showing no adverse chemical reaction against the PIM process, show a residual mass of carbon of about 150 ppm after sintering. Binders system using polystyrene, resistant to radiolysis phenomena and loadable more than 50 %(vol) of actinide powder, shows the promising potential of PIM process for the fuel fabrication. (author) [fr

Spray drying of beryllium oxide powder

International Nuclear Information System (INIS)

Sepulveda, J.L.; Kahler, D.A.

1991-01-01

Forming of beryllia ceramics through dry pressing requires the agglomeration of the powder through spray drying. To produce high quality fired ceramics it is necessary to disperse/grind the primary powder prior to binder addition. Size reduction of the powder is accomplished using an aqueous system in Vibro-Energy mills (VEM) charged with beryllia media to minimize contamination. Two VEM mills of different size were used to characterize the grinding operation. Details of the grinding kinetics are described within the context of the Macroscopic Population Balance Model approach. Spray drying of the ceramic slurry was accomplished with both a centrifugal atomizer and a two fluid nozzle atomizer. Two different spray dryers were used. Important operating parameters affecting the size distribution of the spray dried powder are discussed

Method of producing radioactive carbon powder

International Nuclear Information System (INIS)

Imamura, Y.

1980-01-01

Carbon powder, placed in a hermetically closed apparatus under vacuum together with radium ore, adsorbs radon gas emanating from the radium ore thus producing a radioactive carbonaceous material, the radioactivity of which is due to the presence of adsorbed radon. The radioactive carbon powder thus obtained has excellent therapeutical efficacy and is suitable for a variety of applications because of the mild radioactivity of radon. Radium ore permits substantially limitlessly repeated production of the radioactive carbon powder

Preparation techniques for ceramic waste form powder

International Nuclear Information System (INIS)

Hash, M.C.; Pereira, C.; Lewis, M.A.

1997-01-01

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

Synthesis of a TiBw/Ti6Al4V composite by powder compact extrusion using a blended powder mixture

Energy Technology Data Exchange (ETDEWEB)

Lu, Huiyang, E-mail: hl209@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Zhang, Deliang, E-mail: zhangdeliang@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai (China); Gabbitas, Brian, E-mail: briang@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Yang, Fei, E-mail: fyang@waikato.ac.nz [Waikato Center for Advanced Materials, School of Engineering, University of Waikato, Hamilton (New Zealand); Matthews, Steven, E-mail: S.Matthews@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Auckland (New Zealand)

2014-09-01

Highlights: • TiB/Ti6Al4V composites were prepared from extruded BE powders. • Different starting powders affected the morphologies of TiB whiskers formed in-situ. • A TiB/Ti6Al4V composite with TiB whiskers had good strength and ductility. • The strength and ductility achieved were superior to those obtained by other methods. - Abstract: A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by powder compact extrusion using a blended powder mixture. The microstructural characterization of the various extruded samples showed that the different starting powders, pre-alloyed powder plus boron powder or titanium plus Al–40V master alloy powder plus boron powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study.

Synthesis of a TiBw/Ti6Al4V composite by powder compact extrusion using a blended powder mixture

International Nuclear Information System (INIS)

Lu, Huiyang; Zhang, Deliang; Gabbitas, Brian; Yang, Fei; Matthews, Steven

2014-01-01

Highlights: • TiB/Ti6Al4V composites were prepared from extruded BE powders. • Different starting powders affected the morphologies of TiB whiskers formed in-situ. • A TiB/Ti6Al4V composite with TiB whiskers had good strength and ductility. • The strength and ductility achieved were superior to those obtained by other methods. - Abstract: A Ti–6 wt%Al–4 wt%V alloy (Ti6Al4V) matrix composite, reinforced by in situ synthesized TiB whiskers (TiBw) has been successfully fabricated by powder compact extrusion using a blended powder mixture. The microstructural characterization of the various extruded samples showed that the different starting powders, pre-alloyed powder plus boron powder or titanium plus Al–40V master alloy powder plus boron powder, had a significant effect on the morphology of the in situ synthesized TiB whiskers. It is also evident that the TiB whiskers affect the microstructural evolution of the Ti6Al4V matrix. The tensile test results indicated that the composite with a dispersion of fine TiB whiskers with high aspect ratios exhibited a high ultimate tensile stress (UTS) and yield stress (YS) of 1436 MPa and 1361 MPa, respectively, a reasonably good tensile ductility reflected by an elongation to fracture of 5.6% was also achieved. This is a significant improvement compared with as-extruded monolithic Ti6Al4V alloy produced in this study

(YSZ) powders

Indian Academy of Sciences (India)

Unknown

109–114. © Indian Academy of Sciences. 109 ... Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085, India .... pensions of 900°C calcined YSZ powders. .... The sintered density data of the compacts (sintered at.

Internal Friction Angle of Metal Powders

Directory of Open Access Journals (Sweden)

Jiri Zegzulka

2018-04-01

Full Text Available Metal powders are components with multidisciplinary usage as their application is very broad. Their consistent characterization across all disciplines is important for ensuring repeatable and trouble-free processes. Ten metal powders were tested in the study. In all cases, the particle size distribution and morphology (scanning electron microscope—SEM photos were determined. The aim of this work was to inspect the flow behavior of metal powders through another measured characteristic, namely the angle of internal friction. The measured values of the effective internal friction angle in the range 28.6–32.9°, together with the spherical particle shape and the particle size distribution, revealed the likely dominant mode of the metal particle transfer mechanism for stainless steel 316L, zinc and aluminum powder. This third piston flow mechanism is described and illustrated in detail. The angle of internal friction is mentioned as another suitable parameter for the characterization of metal powders, not only for the relative simplicity of the determination but also for gaining insight into the method of the movement of individual particles during the flow.

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.

Preparation procedure for spherical titanium powders by RF induction plasma

International Nuclear Information System (INIS)

Gu Zhongtao; Jin Yuping; Ye Gaoying

2011-01-01

The paper uses the single-factor method for the study of spherical titanium powder preparation process. Titanium powders with excellent sphericity can be prepared through controlling and regulating the radio frequency plasma anode working current and voltage, central gas flow rate, sheath gas flow rate, powder-carrying gas flow rate, negative ventilation pressure and powder feed rate, etc. Spheroidization of titanium powders with a size of (17.0±2.0) μm is performed by radio frequency plasma technology. With the increase of negative ventilation pressure, the spheroidization rate of titanium powders increases firstly and then decreases rapidly at the turning point around 1800 Pa. With the rate of powder feed increasing, the spheroidization rate of titanium powders increases firstly. When the powder feed rate is greater than 90.0 g/min, the spheroidization rate of titanium powders reduces rapidly as the powder feed rate increases. (authors)

Electrical conductivity of metal powders under pressure

Science.gov (United States)

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

2011-12-01

A model for calculating the electrical conductivity of a compressed powder mass consisting of oxide-coated metal particles has been derived. A theoretical tool previously developed by the authors, the so-called `equivalent simple cubic system', was used in the model deduction. This tool is based on relating the actual powder system to an equivalent one consisting of deforming spheres packed in a simple cubic lattice, which is much easier to examine. The proposed model relates the effective electrical conductivity of the powder mass under compression to its level of porosity. Other physically measurable parameters in the model are the conductivities of the metal and oxide constituting the powder particles, their radii, the mean thickness of the oxide layer and the tap porosity of the powder. Two additional parameters controlling the effect of the descaling of the particle oxide layer were empirically introduced. The proposed model was experimentally verified by measurements of the electrical conductivity of aluminium, bronze, iron, nickel and titanium powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

Study of nuclear fuel powders forming by axial compaction

International Nuclear Information System (INIS)

Fourcade, J.

2002-12-01

Nuclear fuel powders forming, although perfectly dominated, fail to make compacts without density gradients. Density heterogeneities induce diametric deformations during firing which force manufacturers to adjust shape with a high cost machining stage. Manufacturing process improvement is a major project to obtain perfectly shaped pellets and reduce their cost. One way of investigation of this project is the study of powders compaction mechanisms to understand and improve their behaviour. The goal of this study is to identify the main mechanisms linked with powder properties that act on pressing. An empirical model is developed to predict pellet deformations from a single compaction test. This model has to link powder properties with their compaction behaviour. Then, compaction tests identify the main mechanisms whereas a contact dynamic program is used to explain them. These works, done to improve the understanding in powders behaviour, focus on powders agglomeration state and macroscopic particles arrangement during the die filling stage. Actually, for granulated powders, granules cohesion act on the powder bed behaviour under pressure. The first particles arrangement is responsible for the first transfer directions into the powder and so for its transfer homogeneity and isotropy. As a consequence, the knowledge of all the macroscopic powder properties is essential to understand and improve the manufacturing process. Moreover, tests on UO 2 powders have shown that it is better to use granulated powders with spherical granules, short size distribution and granules cohesion according with compaction pressure to improve compact homogeneity of densification. (author)

Radiotreated cocoa powder for frozen elaboration

International Nuclear Information System (INIS)

Rodriguez Jorge, M.; Alvarez Gil, M.; Prieto Miranda, E.; Morales Valladares, M.

1995-01-01

The aim of the present papers is to study the possibilities of 2.0 kGy gamma radiotreated cocoa powder to be used in the elaboration of powder mixture for the preparation of chocolate frozen. Three industrial productions were carried out. Microbiological and organoleptic evaluations of the final product were performed. The results showed that the use of radurized cocoa powder in the frozen elaboration is feasible. A good hygienic quality of this product was obtained and no organoleptic alterations were detected [es

Preparation and utilization of metal oxide fine powder

Energy Technology Data Exchange (ETDEWEB)

Kim, Joon Soo; Jang, Hee Dong; Lim, Young Woong; Kim, Sung Don; Lee, Hi Sun; Lee, Hoo In; Kim, Chul Joo; Shim, Gun Joo; Jang, Dae Kyu [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-01

Metal oxide fine powders finds many applications in industry as new materials. It is very much necessary for the development of such powders to improve the domestic industry. The purpose of present research is to develop a process for the preparation and utilization of metal oxide fine powder. This project is consisted of two main subjects. (1) Production of ultrafine metal oxide powder: Ultrafine metal oxide powder is defined as a metal oxide powder of less than 100 nanometer in particle size. Experiments for the control of particle size and distributions in the various reaction system and compared with results of (2 nd year research). Various reaction systems were adopted for the development of feasible process. Ultrafine particles could be prepared even higher concentration of TiCl{sub 4} and lower gas flowrate compared to TiCl{sub 4}-O{sub 2} system in the TiCl{sub 4}-Air-H{sub 2}O system. Ultrafine Al{sub 2}O{sub 3} powders also prepared with the change of concentration and gas flowrate. Experiments on the treatment of surface characteristics of ultrafine TiO{sub 2} powders were investigated using esterification and surface treating agents. A mathematical model that can predict the particle size and distribution was also developed. (2) Preparation of cerium oxide for high-grade polishing powder: Used cerium polishing powder was recycled for preparation of high grade cerium oxide polishing powder. Also, cerium hydroxide which was generated as by-product in processing of monazite ore was used as another material. These two materials were leached respectively by using acid, and the precipitate was gained in each leached solution by adjusting pH of the solution, and by selective crystallization. These precipitates were calcined to make high grade cerium oxide polishing powder. The effect of several experimental variables were investigated, and the optimum conditions were obtained through the experiments. (author). 81 refs., 49 figs., 27 tabs.

21 CFR 169.182 - Vanilla-vanillin powder.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Vanilla-vanillin powder. 169.182 Section 169.182... Dressings and Flavorings § 169.182 Vanilla-vanillin powder. (a) Vanilla-vanillin powder conforms to the... § 169.3(c) contained therein, the article also contains not more than 1 ounce of added vanillin. (b) The...

Shock-induced modification of inorganic powders

International Nuclear Information System (INIS)

Graham, R.A.; Morosin, B.; Venturini, E.L.; Beauchamp, E.K.; Hammetter, W.F.

1984-01-01

The results of studies performed to quantify the characteristics of TiO2, ZrO2 and Si3N4 powders exposed to explosive loading and post-shock analysis are reported. The shocks were produced with plane wave generators and explosive pads impinging on steel disks, a copper recovery fixture, and then the samples. Peak pressures of 13 and 17 GPa were attained, along with 40 GPz at the center of the powder cavity. Data are provided on the changes occurring during the explosive densification and X-ray and paramagnetic studies of the products. Only fractured disks were obtained in the trials. The shock-treated materials were more free flowing than the original powders, which were fluffy. Post-shock annealing was a significant feature of the treated powders

[The species traceability of the ultrafine powder and the cell wall-broken powder of herbal medicine based on DNA barcoding].

Science.gov (United States)

Xiang, Li; Tang, Huan; Cheng, Jin-le; Chen, Yi-long; Deng, Wen; Zheng, Xia-sheng; Lai, Zhi-tian; Chen, Shi-lin

2015-12-01

Ultrafine powder and cell wall-broken powder of herbal medicine lack of the morphological characters and microscopic identification features. This makes it hard to identify herb's authenticity with traditional methods. We tested ITS2 sequence as DNA barcode in identification of herbal medicine in ultrafine powder and cell wall-broken powder in this study. We extracted genomic DNAs of 93 samples of 31 representative herbal medicines (28 species), which include whole plant, roots and bulbs, stems, leaves, flowers, fruits and seeds. The ITS2 sequences were amplified and sequenced bidirectionally. The ITS2 sequences were identified using Basic Local Alignment Search Tool (BLAST) method in the GenBank database and DNA barcoding system to identify the herbal medicine. The genetic distance was analyzed using the Kimura 2-parameter (K2P) model and the Neighbor-joining (NJ) phylogenetic tree was constructed using MEGA 6.0. The results showed that DNA can be extracted successfully from 93 samples and high quality ITS2 sequences can be amplified. All 31 herbal medicines can get correct identification via BLAST method. The ITS2 sequences of raw material medicines, ultrafine powder and cell wall-broken powder have same sequence in 26 herbal medicines, while the ITS2 sequences in other 5 herbal medicines exhibited variation. The maximum intraspecific genetic-distances of each species were all less than the minimum interspecific genetic distances. ITS2 sequences of each species are all converged to their standard DNA barcodes using NJ method. Therefore, using ITS2 barcode can accurately and effectively distinguish ultrafine powder and cell wall-broken powder of herbal medicine. It provides a new molecular method to identify ultrafine powder and cell wall-broken powder of herbal medicine in the quality control and market supervision.

Spark-plasma sintering and mechanical property of mechanically alloyed NiAl powder compact and ball-milled (Ni+Al) mixed powder compact

International Nuclear Information System (INIS)

Kim, J.S.; Jang, Y.I.; Kwon, Y.S.; Kim, Y.D.; Ahn, I.S.

2001-01-01

Mechanically-alloyed NiAl powder and (Ni+Al) powder mixture prepared by ball-milling were sintered by spark-plasma sintering (SPS) process. Densification behavior and mechanical property were determined from the experimental results and analysis such as changes in linear shrinkage, shrinkage rate, microstructure, and phase during sintering process, Vicker's hardness and transverse rupture strength tests. Densification mechanisms for MA-NiAl powder compact and (Ni+Al) powder mixture were different from each other. While the former showed a rapid increase in densification rate only at higher temperature region of 800-900 o C, the latter revealed firstly a rapid increase in densification rate even at low temperature of 300 o C and a subsequent increase up to 500 o C. Densities of both powder compact (MA and mixture) sintered at 1150 o C for 5 min were 98 and above 99 %, respectively. Sintered bodies were composed mainly of NiAl phase with Ni 3 Al as secondary phase for both powders. Sintered body of MA-NiAl powder showed a very fine grain structure. Crystallite size determined by XRD result and the Sherrer's equation was approximately 80 nm. Vicker's hardness for the sintered bodies of (Ni+Al) powder mixture and MA-NiAl powder were 410±12 H v and 555±10 H v , respectively, whereas TRS values 1097±48 MPa and 1393±75 MPa. (author)

The effect of polymorphism on powder compaction and dissolution properties of chemically equivalent oxytetracycline hydrochloride powders.

Science.gov (United States)

Liebenberg, W; de Villiers, M M; Wurster, D E; Swanepoel, E; Dekker, T G; Lötter, A P

1999-09-01

In South Africa, oxytetracycline is identified as an essential drug; many generic products are on the market, and many more are being developed. In this study, six oxytetracycline hydrochloride powders were obtained randomly from manufacturers, and suppliers were compared. It was found that compliance to a pharmacopoeial monograph was insufficient to ensure the optimum dissolution performance of a simple tablet formulation. Comparative physicochemical raw material analysis showed no major differences with regard to differential scanning calorimetry (DSC), infrared (IR) spectroscopy, powder dissolution, and particle size. However, the samples could be divided into two distinct types with respect to X-ray powder diffraction (XRD) and thus polymorphism. The two polymorphic forms had different dissolution properties in water or 0.1 N hydrochloride acid. This difference became substantial when the dissolution from tablets was compared. The powders containing form A were less soluble than that containing form B.

Electro/powder separation process

International Nuclear Information System (INIS)

Dunn, J.P.

1977-01-01

A report is presented to introduce the ELECTRO/POWDER process to the P/M Industry. The process effectively uses electrostatic forces to convey, sort, meter, and blend fine powders. The major advantages of this separating process consist of the processing of primary particles, low particle energy due to particle velocity control and the pattern of particle movement over the sieve (vertical oscillation of particles above the sieve aperture). The report briefly describes the forces involved in both mechanical and sieving devices, with major emphasis on the operating principles of this process. Sieve separation of particulates is basically the result of two physical separating processes which occur simultaneously or independently; separation (dispersion) of particulates from each other and the size separation by passage through fixed apertures. In order to accomplish this goal, mechanical sieving devices utilize various motions to induce shear forces between the sieve surface and the particulates, and between the particulates themselves. It is noted that the ELECTRO/POWDER process is making steady progress in becoming an industrial tool for sieving and feeding of fine particles. Its potential extends into both the blending and admixing of powders, either by incorporating two opposing feeders, one being charged with the opposite polarity or by modifying the ELECTRO/SIEVE to incorporate more than one input and a solid electrode to replace the sieve electrode

Fe-based nanocrystalline powder cores with ultra-low core loss

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiangyue, E-mail: wangxiangyue1986@163.com [China Iron and Steel Research Institute Group, Beijing 100081 (China); Center of Advanced Technology and Materials Co., Ltd., Beijing 100081 (China); Lu, Zhichao; Lu, Caowei; Li, Deren [China Iron and Steel Research Institute Group, Beijing 100081 (China); Center of Advanced Technology and Materials Co., Ltd., Beijing 100081 (China)

2013-12-15

Melt-spun amorphous Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 15.5}B{sub 7} alloy strip was crushed to make flake-shaped fine powders. The passivated powders by phosphoric acid were mixed with organic and inorganic binder, followed by cold compaction to form toroid-shaped bonded powder-metallurgical magnets. The powder cores were heat-treated to crystallize the amorphous structure and to control the nano-grain structure. Well-coated phosphate-oxide insulation layer on the powder surface decreased the the core loss with the insulation of each powder. FeCuNbSiB nanocrystalline alloy powder core prepared from the powder having phosphate-oxide layer exhibits a stable permeability up to high frequency range over 2 MHz. Especially, the core loss could be reduced remarkably. At the other hand, the softened inorganic binder in the annealing process could effectively improve the intensity of powder cores. - Highlights: • Fe-based nanocrystalline powder cores were prepared with low core loss. • Well-coated phosphate-oxide insulation layer on the powder surface decreased the core loss. • Fe-based nanocrystalline powder cores exhibited a stable permeability up to high frequency range over 2 MHz. • The softened inorganic binder in the annealing process could effectively improve the intensity of powder cores.

Preparation of superconducting powders by freeze-drying

International Nuclear Information System (INIS)

Johnson, S.M.; Gusman, M.I.; Rowcliffe, D.J.; Geballe, T.H.; Sun, J.Z.

1987-01-01

A method of preparing superconducting powders by freeze-drying is described. Powders produced by this method are homogeneous, have high purities, and are very reactive. Materials sintered from these powders have densities up to 89% of the theoretical density, and exhibit very sharp resistivity drops and large Meissner effects. The microstructure of the materials is very sensitive to the sintering temperature

Food powders flowability characterization: theory, methods, and applications.

Science.gov (United States)

Juliano, Pablo; Barbosa-Cánovas, Gustavo V

2010-01-01

Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.

Exploring Oven-drying Technique in Producing Pineapple Powder

Directory of Open Access Journals (Sweden)

Cyril John A. Domingo

2017-11-01

Full Text Available Pineapple puree and juice of 11 to 12 °Brix were used to obtain pineapple powder using oven-drying technique. Addition of maltodextrin in treatments 2 and 4 yielded good quality powder, however addition of sugar and maltodextrin in treatments 1 and 3 resulted to sticky product which was processed to pineapple leather. Treatment 2 composed of pineapple puree and maltodextrin resulted to significantly higher powder recovery compared with treatment 4 which composed of pineapple juice and maltodextrin. The solubility of pineapple powder improved as maltodextrin concentration is increased from 40.00 % to 60.00 %.Addition of maltodextrin also reduced stickiness of the final product. An instant pineapple powder of 5.47 and 5.33 % moisture content could be produced by oven-drying.This level of moisture content will prohibit bacterial growth in the pineapple powder but may have mold or yeast growth with increase storage period at environments with high humidity. Molds were observed on the 17th day at 89.00 % relative humidity as exhibited by the moisture sorption isotherm data. This suggests that appropriate packaging with moisture barrier is recommended for pineapple powder. This study showedthat by using appropriate ratio of juice, puree, and maltodextrin and appropriate oven drying conditions, a good oven-dried pineapple powder could be obtained.

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.

The quantitative characterization of sintering of urania powders

International Nuclear Information System (INIS)

Das, P.; Kulkarni, U.D.

1981-01-01

This paper presents a unified approach towards characterization of the sintering behaviour of UO 2 powders in terms of their extrinsic properties. Empirical equations connecting the sintering index with various powder parameters have been set up. The influence of various powder parameters, either individually or as dimensionless/dimensional groups, on the sintering behaviour has been studied. The relative importance of these factors has also been analysed. A good polynomial fit has been obtained for variation of sintering index with some of the powder parameters and dimensionless/dimensional groups. The equations are expected to provide a good basis for assessing the sinterability of UO 2 powders. (Auth.)

Characterization and Sintering of Armstrong Process Titanium Powder

Science.gov (United States)

Xu, Xiaoyan; Nash, Philip; Mangabhai, Damien

2017-04-01

Titanium and titanium alloys have a high strength to weight ratio and good corrosion resistance but also need longer time and have a higher cost on machining. Powder metallurgy offers a viable approach to produce near net-shape complex components with little or no machining. The Armstrong titanium powders are produced by direct reduction of TiCl4 vapor with liquid sodium, a process which has a relatively low cost. This paper presents a systematic research on powder characterization, mechanical properties, and sintering behavior and of Armstrong process powder metallurgy, and also discusses the sodium issue, and the advantages and disadvantages of Armstrong process powders.

Advances in beryllium powder consolidation simulations

International Nuclear Information System (INIS)

Reardon, B.J.

1998-01-01

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

Strain-enhanced sintering of iron powders

Energy Technology Data Exchange (ETDEWEB)

Amador, D.R.; Torralba, J.M. [Universidad Carlos III de Madrid, Departamento de Ciencias de Materiales e Ingenieria Metalurgica, Leganes, Madrid (Spain); Monge, M.A.; Pareja, R. [Universidad Carlos III de Madrid, Departamento de Fisica, Madrid (Spain)

2005-02-01

Sintering of ball-milled and un-milled Fe powders has been investigated using dilatometry, X-ray, density, and positron annihilation techniques. A considerable sintering enhancement is found in milled powders showing apparent activation energies that range between 0.44 and 0.80 eV/at. The positron annihilation results, combined with the evolution of the shrinkage rate with sintering temperature, indicate generation of lattice defects during the sintering process of milled and un-milled powders. The sintering enhancement is attributed to pipe diffusion along the core of moving dislocations in the presence of the vacancy excess produced by plastic deformation. Positron annihilation results do not reveal the presence of sintering-induced defects in un-milled powders sintered above 1200 K, the apparent activation energy being in good agreement with that for grain-boundary diffusion in {gamma}-Fe. (orig.)

Powder diffractometry

International Nuclear Information System (INIS)

Doucet, J.

1983-01-01

The new possibilities openned by the synchrotron radiation in the powder diffractometry techniques are presented. This technique is described in a general manner and some aspects which can be developed with the use of the synchrotron radiation are analyzed. (L.C.) [pt

Powder metallurgy techniques in nuclear technology

International Nuclear Information System (INIS)

Mardon, P.G.

1983-01-01

The nuclear application of conventional powder metallurgy routes is centred on the fabrication of ceramic fuels. The stringent demands in terms of product performance required by the nuclear industry militate against the use of conventional powder metallurgy to produce metallic components such as the fuel cladding. However, the techniques developed in powder metallurgy find widespread application throughout nuclear technology. Illustrations of the use of these techniques are given in the fields of absorber materials, ceramic cladding materials, oxide fuels, cermet fuels, and the disposal of highly active waste. (author)

Plasma metallization of refractory carbide powders

International Nuclear Information System (INIS)

Koroleva, E.B.; Klinskaya, N.A.; Rybalko, O.F.; Ugol'nikova, T.A.

1986-01-01

The effect of treatment conditions in plasma on properties of produced metallized powders of titanium, tungsten and chromium carbides with the main particle size of 40-80 μm is considered. It is shown that plasma treatment permits to produce metallized powders of carbide materials with the 40-80 μm particle size. The degree of metallization, spheroidization, chemical and phase composition of metallized carbide powders are controlled by dispersivity of the treated material, concentration of a metal component in the treated mixtures, rate of plasma flow and preliminary spheroidization procedure

Net shape powder processing of aluminium

International Nuclear Information System (INIS)

Schaffer, G.B.

2000-01-01

The increasing interest in light weight materials coupled to the need for cost-effective processing have combined to create a significant opportunity for aluminium powder metallurgy. Net shape processing of aluminium using the classical press-and-sinter powder metallurgy technique is a unique and important metal-forming method which is cost effective in producing complex parts at, or very close to, final dimensions. This paper provides an overview of the net shape powder processing of aluminium. Current research is critically reviewed and the future potential is briefly considered

Application of permanent magnets made from NdFeB powder and from mixtures of powders in DC motors

International Nuclear Information System (INIS)

Slusarek, B.; Dudzikowski, I.

2002-01-01

The paper presents the influence of magnetic properties of applied permanent magnets on the characteristics of DC motors excited with these magnets. In the factory-produced DC motors, excited with sintered ferrite magnets, authors replaced ferrite magnets with the dielectromagnets from NdFeB powder and from different mixtures of NdFeB and ferrite powders. The paper shows the increase of the power of the resultant DC motors according to the powders' content

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.

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.

Powder technology

International Nuclear Information System (INIS)

Agueda, Horacio

1989-01-01

Powder technology is experiencing nowadays a great development and has broad application in different fields: nuclear energy, medicine, new energy sources, industrial and home artifacts, etc. Ceramic materials are of daily use as tableware and also in the building industry (bricks, tiles, etc.). However, in machine construction its utilization is not so common. The same happens with metals: powder metallurgy is employed less than traditional metal forming techniques. Both cases deal with powder technology and the forming techniques as far as the final consolidation through sintering processes are very similar. There are many different methods and techniques in the forming stage: cold-pressing, slip casting, injection molding, extrusion molding, isostatic pressing, hot-pressing (which involves also the final consolidation step), etc. This variety allows to obtain almost any desired form no matter how complex it could be. Some applications are very specific as in the case of UO 2 pellets (used as nuclear fuels) but with the same technique and other materials, it is possible to manufacture a great number of different products. This work shows the characteristics and behaviour of two magnetic ceramic materials (ferrites) fabricated in the laboratory of the Applied Research Division of the Bariloche Atomic Center for different purposes. Other materials and products made with the same method are also mentioned. Likewise, densities and shrinkage obtained by different methods of forming (cold-pressing, injection molding, slip casting and extrusion molding) using high-purity alumina (99.5% Al 2 O 3 ). Finally, different applications of such methods are given. (Author) [es

Investigation of pressing of molybdenum powder compacts

International Nuclear Information System (INIS)

Mymrin, S.A.; Kuznetsov, V.Eh.; Yampol'skij, M.L.; Leonov, S.A.; Mikhridinov, R.M.; Korzukhin, V.A.

1990-01-01

Results of an experimental investigation into pressing of compacts of MCh type molybdenum powders using the industrial equipment are presented. To measure the density of powder molybdenum billets a radioisotopic density meter with cesium-137 is used as radioactive gamma radiation source. The dependence of the produced billet density on the specific compacting pressure at different values of the powder bulk density is ascertained

Cryomilling of Thermoplastic Powder for Prepreg Applications

Science.gov (United States)

2013-09-01

Cryomilling of Thermoplastic Powder for Prepreg Applications by Brian Parquette, Anit Giri, Daniel J. O’Brien, Sarah Brennan, Kyu Cho, and...MD 21005-5066 ARL-TR-6591 September 2013 Cryomilling of Thermoplastic Powder for Prepreg Applications Brian Parquette and Sarah Brennan...COVERED (From - To) 1 March 2012–30 May 2013 4. TITLE AND SUBTITLE Cryomilling of Thermoplastic Powder for Prepreg Applications 5a. CONTRACT

Cerebroprotective Actions of Triticum aestivum Linn Powder and Bauhinia purpurea Flower Powder in Surgically Induced Cerebral Infraction in Rats.

Science.gov (United States)

Annapurna, Akula; Vishala, Thonangi C; Bitra, Veera R; Rapaka, Deepthi; Shaik, Asmath

2018-01-01

The prime objective of this study is to evaluate the cerebroprotective actions of Triticum aestivum (wheatgrass) powder and Bauhinia purpurea flower (dev kanchan) powder against the experimentally induced global ischemia reperfusion injury in rats. In the first phase of the studies, 1 h before the surgical procedure, the Wistar rats were orally served with varied doses of wheatgrass powder (5, 10, 30, and 100 μg/kg) and Bauhinia flower powder (30, 100, 200, and 300 μg/kg), respectively. The ischemia was induced by 30-min bilateral carotid artery occlusion in succession to reperfusion for 4 h. It was proved that the wheatgrass powder and Bauhinia flower powder yielded a significant, dose-dependent cerebroprotection in terms of reduction in cerebral infarct size when compared with the control group. Coming to the second phase of the studies, a certain potential dose of 10 μg/kg of wheatgrass and 200 μg/kg of Bauhinia flower powders was selected keeping the protective action in view, and the animals were treated for 15 days. The major findings of the study are that wheatgrass and Bauhinia flower powders significantly augmented the magnitude of the antioxidant enzymes, viz., super oxide dismutase and catalase, and further reduced the levels of lipid peroxidation. The present study clearly showed that the wheatgrass powder and Bauhinia flower powder possess significant antioxidant properties that may act as a key ingredient in various ayurvedic preparations for the treatment of various diseases like cerebral ischemic reperfusion injury. The wheat grass contains high amount of bioflavonoids, alkaloids, SOD etc which are responsible for anti oxidant activity.The Bauhinia purpurea contains glycosides, flavonoids and also plays a major role in DPPH activity which is responsible for anti oxidant activity.The wheat grass (10 mg/kg) and bauhinia (200 mg/kg) significantly(P bauhinia (200 mg/kg) significantly (P <0.0001) reduced the lipid peroxidation (MDA) and increased SOD

Free radical interactions between raw materials in dry soup powder.

Science.gov (United States)

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

2011-12-01

Interactions at the free radical level were observed between dry ingredients in cauliflower soup powder, prepared by dry mixing of ingredients and rapeseed oil, which may be of importance for quality deterioration of such dry food products. The free radical concentrations of cauliflower soup powder, obtained by electron spin resonance (ESR) spectroscopy, rapidly become smaller during storage (40°C and relative humidity of 75%) than the calculated concentrations of free radicals based on the free radical concentrations of the powder ingredients used to make the soup powder and stored separately under similar conditions. Similarly, free radical concentrations decreased faster when any combination of two powder ingredients (of the three major ingredients of the soup powder) were mixed together and stored at 50°C for 1week than when each powder component was stored separately. Furthermore, yeast extract powder was found to play a key role when free radical interactions between powder ingredients occurred. The incubation of rapeseed oil with powder ingredients at 45°C for 24h, indicated the ability of cauliflower powder to increase the concentration of hydroperoxides in rapeseed oil, while yeast extract powder was found to prevent this hydroperoxide formation. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

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

Some aspects of UO{sub 2} powder production

Energy Technology Data Exchange (ETDEWEB)

Balakrishna, P; Asnani, C K; Prabhakar Rao, L; Kartha, R M; Pillai, P K.M. [Nuclear Fuel Complex, Hyderabad (India)

1994-06-01

UO{sub 2} powder is being produced in a chemical plant from enriched UF{sub 6} and supplied to the pelletizing plant. Small quantities of scrap UO{sub 2} received back from the pelletizing plant are also recycled in the chemical plant to produce UO{sub 2} powder. The powder should be of a consistently high quality so as to finally yield high density sintered pellets with minimum rejection. The final yield of acceptable finished pellets depends on the quality of the powder in the chemical plant as well as the quality of pressing in the pelletizing plant. In this paper, some examples of measures adopted for achieving good quality powder production are presented. (author). 9 refs., 2 figs.

Introduction to powder metallurgy processes for titanium manufacturing

International Nuclear Information System (INIS)

Esteban, P. G.; Bolzoni, L.; Ruiz-Navas, E. M.; Gordo, E.

2011-01-01

The development of new extraction processes to produce titanium in powder form leads Powder Metallurgy to an advantage position among the manufacturing processes for titanium. The cost reduction of base material, coupled with the economy of the powder metallurgy processes, give titanium industry the chance to diversify its products, which could lead to production volumes able to stabilise the price of the metal. This work reviews some of the Powder Metallurgy techniques for the manufacturing of titanium parts, and describes the two typical approaches for titanium manufacturing: Blending Elemental and Prealloyed Powders. Among others, conventional pressing and sintering are described, which are compared with cold and hot isostatic pressing techniques. Real and potential applications are described. (Author) 71 refs.

Characterization of powdered fish heads for bone graft biomaterial applications.

Science.gov (United States)

Oteyaka, Mustafa Ozgür; Unal, Hasan Hüseyin; Bilici, Namık; Taşçı, Eda

2013-01-01

The aim of this study was to define the chemical composition, morphology and crystallography of powdered fish heads of the species Argyrosomus regius for bone graft biomaterial applications. Two sizes of powder were prepared by different grinding methods; Powder A (coarse, d50=68.5 µm) and Powder B (fine, d50=19.1 µm). Samples were analyzed using X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), thermogravimetry (TG), and energy dispersive X-ray spectroscopy (EDS). The powder was mainly composed of aragonite (CaCO3) and calcite (CaCO3). The XRD pattern of Powder A and B matched standard aragonite and calcite patterns. In addition, the calcium oxide (CaO) phase was found after the calcination of Powder A. Thermogravimetry analysis confirmed total mass losses of 43.6% and 47.3% in Powders A and B, respectively. The microstructure of Powder A was mainly composed of different sizes and tubular shape, whereas Powder B showed agglomerated particles. The high quantity of CaO and other oxides resemble the chemical composition of bone. In general, the powder can be considered as bone graft after transformation to hydroxyapatite phase.

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 we......, should facilitate a compaction. The passivation layer, however, impedes a compaction. Isostatic pressing at 540 K at a pressure of 200 MPa clearly illustrated this; pellets pressed from passivated powder were much more brittle than pellets pressed from unpassivated powder. The density of the pellets...... was very low ([approximately-equal-to]25% of the density of bulk FeB). We have designed a die for uniaxial pressing in which the compaction can be performed without exposing the powder to air and have obtained densities larger than 60% of that of bulk FeB. We have reported studies of the dependence...

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.

Properties of magnetic nickel/porous-silicon composite powders

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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.

Dispersion-strengthened Aluminium Products Manufactured by Powder Blending

DEFF Research Database (Denmark)

Hansen, Niels

1969-01-01

Detailed experiments carried out to examine relationship between microstructure and mechanical properties of powder-blended aluminum products are reported; their results as well as structural studies by transmission electron microscopy and tensile-and creep- testing, are given; as dispersed phase......, various oxide powders were selected on criterion that during manufacturing no reaction must taken place between metal and oxide phase; strength of powder-blended aluminum products increases and elongation decreases with decreasing particle size of aluminum powder and with increasing concentration of oxide...

Novel Fe-based nanocrystalline powder cores with excellent magnetic properties produced using gas-atomized powder

Science.gov (United States)

Chang, Liang; Xie, Lei; Liu, Min; Li, Qiang; Dong, Yaqiang; Chang, Chuntao; Wang, Xin-Min; Inoue, Akihisa

2018-04-01

FeSiBPNbCu nanocrystalline powder cores (NPCs) with excellent magnetic properties were fabricated by cold-compaction of the gas-atomized amorphous powder. Upon annealing at the optimum temperature, the NPCs showed excellent magnetic properties, including high initial permeability of 88, high frequency stability up to 1 MHz with a constant value of 85, low core loss of 265 mW/cm3 at 100 kHz for Bm = 0.05 T, and superior DC-bias permeability of 60% at a bias field of 100 Oe. The excellent magnetic properties of the present NPCs could be attributed to the ultrafine α-Fe(Si) phase precipitated in the amorphous matrix and the use of gas-atomized powder coated with a uniform insulation layer.

Dry and coating of powders

International Nuclear Information System (INIS)

Alonso, M.; Alguacil, F. J.

1999-01-01

This paper presents a review on the mixing and coating of powders by dry processes. The reviews surveys fundamental works on mixture characterization (mixing index definitions and sampling techniques), mixing mechanisms and models, segregation with especial emphasis on free-surface segregation, mixing of cohesive powders and interparticle forces, ordered mixing (dry coating) including mechanism, model and applications and mixing equipment selection. (Author) 180 refs

Factors affecting the electrostatic charge of ceramic powders

International Nuclear Information System (INIS)

Lorite, I.; Romero, J.; Fernandez, J. F.

2011-01-01

The phenomenon of electrostatic charge in ceramic powders takes place when the particle surfaces enter in contact between them or with the containers. The accumulation of electrostatic charge is of relevance in ceramic powders in view of their insulating character and the risk of explosions during the material handling. In this work the main factors that affect the appearance of intrinsic charge and tribo-charge in ceramic powder have been studied. In ceramic powders of alumina it has been verified that the smallest particle sizes present an increase of the electrostatic charge of negative polarity. A correlation has been observed between the nature of the OH -surface groups and the electrostatic charge. The intrinsic charge and the tribocharge in ceramic powders can be diminished by compensating the surface groups that support the charge. The dry dispersion of nanoparticles on microparticles allows surface charge compensation with a noticeable modification of the powder agglomeration. (Author) 19 refs.

Biodegradation of thermoplastic starch/eggshell powder composites.

Science.gov (United States)

Bootklad, Munlika; Kaewtatip, Kaewta

2013-09-12

Thermoplastic starch (TPS) was prepared using compression molding and chicken eggshell was used as a filler. The effect of the eggshell powder (EP) on the properties of TPS was compared with the effect of commercial calcium carbonate (CC). The organic compound on the surface of the eggshell powder acted as a coupling agent that resulted in a strong adhesion between the eggshell powder and the TPS matrix, as confirmed by SEM micrographs. The biodegradation was determined by the soil burial test. The TPS/EP composites were more rapidly degraded than the TPS/CC composites. In addition, the eggshell powder improved the water resistance and thermal stability of the TPS. Copyright © 2013 Elsevier Ltd. All rights reserved.

Role of forgings in powder metallurgy industry

International Nuclear Information System (INIS)

Hayes, A.F.; DeRidder, A.J.

1975-01-01

Forging of powder metallurgy materials is discussed. Information and data are included on forging powder metallurgy W, Mo, In 100, Rene 95, Astroloy, Be, and Ti. It is noted that the combination of powder metallurgy and forging work provides the best product from standpoints of reproducibility, freedom from segregation, low scrap rate, and uniform mechanical properties. Experience is being used to develop contour forging from hot isostatic pressed billets or preforms. The quality of this product is under evaluation. Results show steady improvement and it is anticipated that continued effort will soon produce a reliable, less costly product. Forging can continue to be relied upon to correct subtle defects present in powder metallurgy material

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.

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

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.

Optimization of Premix Powders for Tableting Use.

Science.gov (United States)

Todo, Hiroaki; Sato, Kazuki; Takayama, Kozo; Sugibayashi, Kenji

2018-05-08

Direct compression is a popular choice as it provides the simplest way to prepare the tablet. It can be easily adopted when the active pharmaceutical ingredient (API) is unstable in water or to thermal drying. An optimal formulation of preliminary mixed powders (premix powders) is beneficial if prepared in advance for tableting use. The aim of this study was to find the optimal formulation of the premix powders composed of lactose (LAC), cornstarch (CS), and microcrystalline cellulose (MCC) by using statistical techniques. Based on the "Quality by Design" concept, a (3,3)-simplex lattice design consisting of three components, LAC, CS, and MCC was employed to prepare the model premix powders. Response surface method incorporating a thin-plate spline interpolation (RSM-S) was applied for estimation of the optimum premix powders for tableting use. The effect of tablet shape identified by the surface curvature on the optimization was investigated. The optimum premix powder was effective when the premix was applied to a small quantity of API, although the function of premix was limited in the case of the formulation of large amount of API. Statistical techniques are valuable to exploit new functions of well-known materials such as LAC, CS, and MCC.

Production and properties of boride powders

International Nuclear Information System (INIS)

Klinskaya, N.A.; Koroleva, E.B.; Petrunichev, V.A.

1990-01-01

Results of plasma metallization of boride powders 40-80 μ diam. are presented. Peculiarities of changes of granulometric powder composition and of metallic cover on refractory cores were investigated. There are shown size- and compositional cores effects on metallization level of poders and on cover structure

Quality of clay-powders of industrial assortment

Energy Technology Data Exchange (ETDEWEB)

Lityayeva, Z A; Dzetl, B G; Goncharenko, N N; Naurova, I V; Rybchenko, V I; Voyevodin, L I

1979-01-01

Nomenclature was developed for the quality indicators of clay powders which took into consideration the foreign experience, and it is suggested that a suspension of clay powders be viewed as the simplest type of drilling. In this case the technique of preparing the suspensions approaches the maximum to that used in the recommended standard (TU-39-043-074). The output of solution is determined with standardized effective viscosity /eta/ ef =/sup 20/ /SUP cP/ on a series domestic rotary viscosimeter VSN-3 with gradient of shear velocity EPSILON=666 sec/sup -1/; with EPSILON=1022 sec /sup -1//eta/ /SUB ef/ = 15 cP. This makes it possible to obtain data comparable to the foreign standards regarding the output of the fluid from the powders. According to the suggested technique, the clay powder is dispersed for 20-30 minutes in water or saturated solution of NaC1 in a mixing unit ''Voronezh2'' with rotation frequency of 9000 rpm, is left to rest and is again dispersed for 15 minutes. Then the dynamic shear stress (P /SUB k2/ ), plastic viscosity (/eta/ /SUB ef/ ), coefficients of coagulation (K /SUB c/ ) and thyxotropic (K /SUB T/ ) structure-formation are defined. Measurements are made on the instrument FLR-1 of water output with 0.7 (B) or 0.1 (B) MPa. According to this technique, a comparison was made of the domestic powders of industrial assortment with the powder ''Aquagel'' widely used abroad. It was established that only the modified concrete powders with correct selection of reagents can compete with the foreign.

3D Model Studies on the Effect of Bed and Powder Type Upon Radial Static Pressure and Powder Distribution in Metallurgical Shaft Furnaces

Directory of Open Access Journals (Sweden)

Panic B.

2017-09-01

Full Text Available The flow of gases in metallurgical shaft furnaces has a decisive influence on the course and process efficiency. Radial changes in porosity of the bed cause uneven flow of gas along the radius of the reactor, which sometimes is deliberate and intentional. However, holdup of solid particles in descending packed beds of metallurgical shaft furnaces can lead to unintentional changes in porosity of the bed along the radial reactor. Unintentional changes in porosity often disrupt the flow of gas causing poor performance of the furnace. Such disruptions of flow may occur in the blast furnace due to high level of powder content in gas caused by large amount of coal dust/powder insufflated as fuel substitute. The paper describes the model test results of radial distribution of static pressure and powder hold up within metallurgical reactor. The measurements were carried out with the use of 3D physical model of two-phase flow gas-powder in the moving (descending packed bed. Sinter or blast furnace pellets were used as packed bed while carbon powder or iron powder were used as the powder. Wide diversity within both static pressure distribution and powder distribution along the radius of the reactor were observed once the change in the type of powder occurred.

Advances in food powder agglomeration engineering.

Science.gov (United States)

Cuq, B; Gaiani, C; Turchiuli, C; Galet, L; Scher, J; Jeantet, R; Mandato, S; Petit, J; Murrieta-Pazos, I; Barkouti, A; Schuck, P; Rondet, E; Delalonde, M; Dumoulin, E; Delaplace, G; Ruiz, T

2013-01-01

Food powders are used in everyday life in many ways and offer technological solutions to the problem of food production. The natural origin of food powders, diversity in their chemical composition, variability of the raw materials, heterogeneity of the native structures, and physicochemical reactivity under hydrothermal stresses contribute to the complexity in their behavior. Food powder agglomeration has recently been considered according to a multiscale approach, which is followed in the chapter layout: (i) at the particle scale, by a presentation of particle properties and surface reactivity in connection with the agglomeration mechanisms, (ii) at the mechanisms scale, by describing the structuration dynamics of agglomerates, (iii) at the process scale, by a presentation of agglomeration technologies and sensors and by studying the stress transmission mode in the powder bed, and finally (iv) by an integration of the acquired knowledge, thanks to a dimensional analysis carried out at each scale. Copyright © 2013 Elsevier Inc. All rights reserved.

Properties and sinterability of wet and dry attrition-milled OREOXed powder

International Nuclear Information System (INIS)

Lee, J. W.; Kim, J. H.; Kim, W. K.; Park, K. I.; Lee, J. W.

2001-01-01

The powder properties and sinterability were investigated with the powder prepared by wet and dry attrition milling of OREOX-treated powder. The OREOX-treated powder was prepared from the simulated spent fuel. Powder having less than 1 μm of average particle size could be obtained by dry milling, but not be obtained by wet milling. Thus, specific surface area of dry milled powder was higher than that of wet milled powder. With increasing of milling time, dry milled powder formed dense agglomerate while wet milled powder showed loose agglomerate. The pellets with higher than 95% T.D. of sintered density and larger than 7 μm of grain size were made with the milled powder regardless of milling method. The milling time in wet milling has greatly improved the sinterability. The pellets produced with dry milled powder have higher sintered density and larger grain size

Dielectric properties of tantalum powder with broccoli-like morphology

Energy Technology Data Exchange (ETDEWEB)

Baba, Masahiko [Department of Energy Science and Technology, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Suzuki, Ryosuke O [Department of Energy Science and Technology, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2005-04-19

Metallic tantalum powder with broccoli-like morphology, consisting of spherical fine particles and of long rods or thin plates, was prepared in a hundred gram scale by calcium reduction of Ta{sub 2}O{sub 5} in molten CaCl{sub 2}. The properties as electrolytic capacitor were evaluated in comparison with commercial powder obtained by Na reduction and with powder consisting of only fine particles obtained by Ca reduction. The capacitance was larger than that of conventional powder with the same surface area, because the broccoli-like powder showed a strong resistance against shrinkage during high temperature annealing due to the framework of branches. The powder with new broccoli-like morphology can circumvent the conventional treatments for grain size control and gas removal.

Dielectric properties of tantalum powder with broccoli-like morphology

International Nuclear Information System (INIS)

Baba, Masahiko; Suzuki, Ryosuke O.

2005-01-01

Metallic tantalum powder with broccoli-like morphology, consisting of spherical fine particles and of long rods or thin plates, was prepared in a hundred gram scale by calcium reduction of Ta 2 O 5 in molten CaCl 2 . The properties as electrolytic capacitor were evaluated in comparison with commercial powder obtained by Na reduction and with powder consisting of only fine particles obtained by Ca reduction. The capacitance was larger than that of conventional powder with the same surface area, because the broccoli-like powder showed a strong resistance against shrinkage during high temperature annealing due to the framework of branches. The powder with new broccoli-like morphology can circumvent the conventional treatments for grain size control and gas removal

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.)

Development and directions of powder diffraction on proteins

International Nuclear Information System (INIS)

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.

2007-01-01

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.)

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

International Nuclear Information System (INIS)

Gülsoy, H. Özkan; Özgün, Özgür; Bilketay, Sezer

2016-01-01

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.

Some characteristics of urea-formaldehyde powder adhesives

Directory of Open Access Journals (Sweden)

Miljković Jovan

2006-01-01

Full Text Available Urea-formaldehyde (UF glue resins were the most important type of adhesives in the wood industry last 60 years, especially for the production of wood based panels. More convenient spray dried UF powders went into use last two decades. Small and medium private wood processing plants in Serbia prefer to use such powder adhesives, since they are more convenient for small capacity production. There is no production of UF powder resin in Serbia so necessary quantities are imported from abroad including producers from Asia. However, their characteristics are variable, dependent on syntheses steps and not well known among users. Objective of this research was to determine conveniences and lacks in application of two imported UF powder resins in comparison to domestic UF emulsion.

Nanostructured hydroxyapatite powders produced by a flame-based technique

Energy Technology Data Exchange (ETDEWEB)

Trommer, R.M., E-mail: rafael_trommer@yahoo.com.br [Ceramic Materials Laboratory, av. Osvaldo Aranha 99/705, 90035190, Porto Alegre, RS (Brazil); Santos, L.A. [Biomaterials Laboratory, av. Bento Goncalves 9500, Campus do Vale Setor IV Predio 74 Sala 123, 91501970, Porto Alegre, RS (Brazil); Bergmann, C.P. [Ceramic Materials Laboratory, av. Osvaldo Aranha 99/705, 90035190, Porto Alegre, RS (Brazil)

2009-08-01

In this work we reported the production of hydroxyapatite (HA) powder, one of the most studied calcium phosphates in the bioceramics field, using a cost-effective apparatus, composed by three major components: the atomization device, the pilot and main flames and finally the powder collector system. Calcium acetate and ammonium phosphate, diluted in ethanol and water, were used as salts in the precursor solution. The Ca/P molar ratio in the precursor solution was 1.65, equivalent to biological hydroxyapatite. After its production and collection, HA powder was calcined at 600 deg. C for 2 h. X-ray diffraction analysis pointed to the formation of crystalline hydroxyapatite powders. Carbonate was identified in the powders by Fourier-transform infrared (FTIR) spectroscopy. Scanning electronic microscopy (SEM) showed that the powders were composed of spherical primary particles and secondary aggregates, with the morphology unchanged after calcination. By transmission electronic microscopy (TEM), it was observed that the crystallite size of the primary particles was 24.8 {+-} 5.8 nm, for the calcined powder. The specific surface area was 15.03 {+-} 6.4 and 26.50 {+-} 7.6 m{sup 2}/g, for the as-synthetized and calcined powder respectively.

[Study of relationship between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite powder].

Science.gov (United States)

Chai, Feng; Xu, Ling; Liao, Yun-mao; Chao, Yong-lie

2003-07-01

The fabrication of all-ceramic dental restorations is challenged by ceramics' relatively low flexural strength and intrinsic poor resistance to fracture. This paper aimed at investigating the relationships between powder-size gradation and mechanical properties of Zirconia toughened glass infiltrated nanometer-ceramic composite (Al(2)O(3)-nZrO(2)). Al(2)O(3)-nZrO(2) ceramics powder (W) was processed by combination methods of chemical co-precipitation and ball milling with addition of different powder-sized ZrO(2). Field-emission scanning electron microscopy was used to determine the particle size distribution and characterize the particle morphology of powders. The matrix compacts were made by slip-casting technique and sintered to 1,450 degrees C and flexural strength and the fracture toughness of them were measured. 1. The particle distribution of Al(2)O(3)-nZrO(2) ceramics powder ranges from 0.02 - 3.5 micro m and among them the superfine particles almost accounted for 20%. 2. The ceramic matrix samples with addition of nZrO(2) (W) showed much higher flexural strength (115.434 +/- 5.319) MPa and fracture toughness (2.04 +/- 0.10) MPa m(1/2) than those of pure Al(2)O(3) ceramics (62.763 +/- 7.220 MPa; 1.16 +/- 0.02 MPa m(1/2)). The particle size of additive ZrO(2) may impose influences on mechanical properties of Al(2)O(3)-nZrO(2) ceramics matrix. Good homogeneity and reasonable powder-size gradation of ceramic powder can improve the mechanical properties of material.

On suitability of novel fluidised bed technique for separation of metallic powders during commercial powder metallurgical processing

NARCIS (Netherlands)

Ritherdon, J; Dechsiri, C; Jones, AR; Hoffmann, AC; Wright, IG

Experiments have been performed to test the efficiency with which a novel fluidised bed technique could separate different metallic powders in terms of size and density. The overall aim was to assess the potential of this technique for the commercial separation of defective powder fractions from

Study on Quality Aggregate Construction Powder

International Nuclear Information System (INIS)

Myat Ko; Kyaw Naing; Thazin Lwin; Khin Mar Tun

2008-03-01

This research work deals with a view to promote cement replacement materials i-e aggregate construction powder, also known as building powder or construction powder . It has been used as lime substituent in construction work in Myanmar since 1990's. It is mixed with other construction materials such as cement, sand, etc. and used in plastering, tiling, arranging bricks and smoothing the face of the buildings.This work also deals with some aspects in physical properties of four different aggregate construction powder samples such as Moe Hein, Man Thiri, Shwe Taung and Kyauk Sue. In addition, these four different samples were characterized by using spectroscopic methods such as ED-XRF, AAS, FT-IR and XRD. In support of the finding by the analytical assays of Moe Hein aggregate construction powder, it indicated the percent composition of the presence of SiO2 12.13%, Al2O3 7.40%, Fe2O3 0.94%, CaO 41.00%,MgO 1.50% total sulphur 1.15%, chloride 1.49%, carbonate 43.63% and sulphate 3.44%. The analytical assays of Sin Min cement, Kyant cement, brick powder and pozzolan were also carried out in this research work. The mixing between various ratios of Moe Hein and Kyant cement as well as Sin Min II cement were done and their mechanical strengths such as setting time, tensile strength and compressive strength of each sample were studied. The quality of mixing ratio 50:50 of Moe Hein and Kyant cement was found to be comparable to the ASTM standard type II Protland cement which is for general use.

Strength Improvement of Clay Soil by Using Stone Powder

Directory of Open Access Journals (Sweden)

Ahmed Sameer Abdulrasool

2015-05-01

Full Text Available Soil stabilization with stone powder is a good solution for the construction of subgrade for road way and railway lines, especially under the platforms and mostly in transition zones between embankments and rigid structures, where the mechanical properties of supporting soils are very influential. Stone powder often has a unique composition which justifies the need for research to study the feasibility of using this stone powder type for ground improvement applications. This paper presents results from a comprehensive laboratory study carried out to investigate the feasibility of using stone powder for improvement of engineering properties of clays. The stone powder contains bassanite (CaSO4. ½ H2O, and Calcite (CaCO3. Three percentages are used for stone powder (1%, 3% and 5% by dry weight of clay. Several tests are made to investigate the soil behavior after adding the stone powder (Atterberg limits, Standard Proctor density, Grain size distribution, Specific gravity, Unconfined Compressive test, and California bearing ratio test. Unconfined Compressive tests conducted at different curing. The samples are tested under both soaked and unsoaked condition. Chemical tests and X-ray diffraction analyses are also carried out. Stone powder reacts with clay producing decreasing in plasticity and The curves of grain size distribution are shifted to the coarse side as the stone powder percentage increase; the soil becomes more granular, and also with higher strength.

Production of rare earth polishing powders in Russia

International Nuclear Information System (INIS)

Kosynkin, V.D.; Ivanov, E.N.; Kotrekhov, V.A.; Shtutza, M.G.; Grabko, A.I.

1998-01-01

Full text: Russia is a potent producer of polishing powders made of rare earth material presented as an extensive and well developed base. Considering the reserves, the facilities predisposition and the polishing agent (cerium dioxide) content the chief mineral source is loparite, apatite and monazite. The production of rare earth polishing powders is based on specially developed continuous technological processes, corrosion-proof equipment, ensuring a high and stable production quality. A special attention is paid to the radiation safety of the powders. The initial material for the rare earth polishing powders based on loparite is the fusion cake of rare earth chlorides obtained at that mineral chlorination. The technology of the polishing powder production from the REE fusion cake includes the following stages: dissolution of the REE fusion cake chlorides; - thorough cleaning of the REE fusion cake chlorides from radioactive and non-rare-earth impurities; chemical precipitation of REE carbonates, obtaining middlings with proper material and granulometric composition, thermal treatment of precipitated carbonates followed with the operations of drying and roasting; classification of roasted oxides, obtaining end products - polishing powders. The production of fluorine-containing powders includes the stage of their fluorination after the stage of carbonate precipitation. The stabilizing doping can be introduced both into the middlings during one of the technological process of powders manufacturing and into the end product. Rare earth polishing powders are manufactured in Russia by the Share Holding Company 'Chepetz Mechanical Plant' (ChMP Co.), the city of Glasov. The plant produces a number of polishing materials, such as; polishing powder Optinol, containing at least 50% by mass of cerium dioxide, used in the mass production of optical and other articles; polishing powder Optinol-10 with doping to improve the sedimentary and aggregate stability of the solid phase

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

21 CFR 176.350 - Tamarind seed kernel powder.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Tamarind seed kernel powder. 176.350 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a component of articles intended for use in producing...

Preparation of potassium-reduced tantalum powders

International Nuclear Information System (INIS)

Kolosov, V.N.; Miroshnichenko, M.N.; Orlov, V.M.; Prokhorova, T.Yu.

2005-01-01

Characteristics of tantalum powders prepared by reduction of molten potassium heptafluorotantalate with liquid potassium are studied in a temperature range of 750 - 850 deg C using potassium chloride as a flux at a ratio of K 2 TaF 7 : KCl = 1, 2, and 3. The use of potassium as a reducing agent facilitates washing of tantalum powders for impurity salt removal, reduces sodium content and leakage currents in the anodes. As compared to sodium process, the potassium reduction results in a high yield of sponge material, a decrease in the specific surface area and yield of tantalum powder suitable for manufacture of capacitor anodes [ru

Determination of the functional properties of Kappaphycus alvarezii seaweed powder

International Nuclear Information System (INIS)

Sjamsiah; Nazaruddin Ramli; Rusli Daik; Mohd Ambar Yarmo

2013-01-01

Seaweed Kappaphycus alvarezii powder prepared by spray drying (SD), freeze drying (FD) and sun drying(SND) were determined their functional properties such as swelling capacity (SWC), water holding capacity (WHC), oil holding capacity (OHC), viscosity and gel strength. The study showed that the Kappaphycus alvarezii seaweed powder obtained by FD and SND have the ability to swell to 25 mL/ g and 50 mL/ g respectively, while the SD powder formed a homogeneous solution and it exhibited highly viscous solution (SWC 100 mL/ g). The WHC of SND powder (30.67 g/ g) was higher (p<0.05) than the FD (21.33 g/ g) and SD (4.67 g/ g) powders. The OHC of FD powder (19.81 g/ g) was higher (p<0.05) than the SD (5.11 g/ g) and SND (4.67 g/ g) powders. While the viscosity of the FD, SND and SD powders were 0.22, 0.17 and 0.06 Pa.s respectively. Meanwhile, the gel strength of the SD powder (82.77 gf) was higher (p<0.05) than the FD (57.1 gf) and SND (35.01 gf) powders. These results on determination of functional properties shows that the SD powder had the most potential to be applied as a viscosity modifier in the manufacturing of beverages.(author)

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

Science.gov (United States)

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

2016-03-01

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

Preparation of cerium oxide for lens polishing powder

International Nuclear Information System (INIS)

Injarean, Uthaiwan; Rodthongkom, Chouvana; Pichestapong, Pipat; Changkrurng, Kalaya

2003-10-01

Cerium is an element of rare earth group which is called lanthanide series. It is found in the ores like monazite and xenotime which are the tailings of tin mines in the south of Thailand. Cerium is used mostly as lens polishing powder besides the applications in other industries. In this study, cerium extracted from monazite ore breakdown by alkaline process was used for the preparation of lens polishing powder. Cerium hydroxide cake from the process was dissolved by hydrochloric acid and precipitated with oxalic acid. The oxalate precipitate then was calcined to oxide powder and its particle size was measured. Precipitation conditions being studied are concentration of feed cerium chloride solution, concentration of oxalic acid used for the precipitation, concentration of sulfuric acid used as precipitation control reagent and the precipitation temperature. It was found that the appropriate precipitation conditions yielded the fine oxide powder with particle size about 12μm. The oxide powder can be ground to the size of 1-3 μm which is suitable for making lens polishing powder

21 CFR 73.1646 - Bronze powder.

Science.gov (United States)

2010-04-01

... percent. Maximum particle size 45µ (95 percent minimum). Aluminum, zinc, tin, and copper content shall be based on the weight of the dried powder after being thoroughly washed with ether. (c) Uses and restrictions. Bronze powder may be safely used in color externally applied drugs, including those intended for...

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 ...

Aluminum powder size and microstructure effects on properties of boron nitride reinforced aluminum matrix composites fabricated by semi-solid powder metallurgy

International Nuclear Information System (INIS)

Chen, Cunguang; Guo, Leichen; Luo, Ji; Hao, Junjie; Guo, Zhimeng; Volinsky, Alex A.

2015-01-01

Al matrix composite reinforced by hexagonal boron nitride (h-BN) with nearly full densification was successfully fabricated by the semi-solid powder metallurgy technique. The h-BN/Al composites were synthesized with elemental pure Al powder size of d_5_0=35, 12 and 2 μm. The powder morphology and the structural characteristics of the composites were analyzed using X-ray diffraction, scanning and transmission electron microscopy. The density, Brinell hardness and compressive behavior of the samples were characterized. Density measurement of the Al composites revealed that the composite densification can be effectively promoted by plenty of embedded liquid phase under pressure. Composites prepared using Al powder with varying granularity showed different grain characteristics, and in situ recrystallization occurred inside the original grains with 35 μm Al powder. A sharp interface consisting of Al/Al_2O_3/h-BN was present in the composites. Both the compressive strength and the fracture strain of the investigated composites increased with the decrease of the Al powder size, along with the Brinell hardness. The composite with 2 μm Al powder exhibited the highest relative density (99.3%), Brinell harness (HB 128), compressive strength (763 MPa) and fracture strain (0.299).

Powder processing and spheroidizing with thermal inductively coupled plasma

International Nuclear Information System (INIS)

Nutsch, G.; Linke, P.; Zakharian, S.; Dzur, B.; Weiss, K.-H.

2001-01-01

Processing of advanced powder materials for the spraying industry is one of the most promising applications of the thermal RF inductively coupled plasma. By selecting the feedstock carefully and adjusting the RF plasma parameters, unique materials with high quality can be achieved. Powders injected in the hot plasma core emerge with modified shapes, morphology, crystal structure and chemical composition. Ceramic oxide powders such as Al 2 O 3 , ZrO 2 , SiO 2 are spheroidized with a high spheroidization rate. By using the RF induction plasma spheroidizing process tungsten melt carbide powders are obtained with a high spheroidization rate at high feeding rates by densification of agglomerated powders consisting of di-tungsten carbide and monocarbide with a definite composition. This kind of ball-like powders is particularly suited for wear resistant applications. (author)

Emerging Applications Using Magnesium Alloy Powders: A Feasibility Study

Science.gov (United States)

Tandon, Rajiv; Madan, Deepak

The use of powder metallurgy offers a potential processing route based on tailored compositions and unique microstructures to achieve high performance in magnesium alloys. This paper highlights recent advances in the production, qualification, and characterization of gas atomized AZ91E, WE43 and Elektron21 alloy powders. Transmission electron microscopy (TEM) was used to understand the bulk and surface structure of the atomized powder. The potential for using these magnesium alloy powders for emerging applications involves establishing compatibility with viable consolidation processes such as cold spray, laser assisted deposition, forging and extrusion. This study summarizes the preliminary results for various ongoing investigations using WE43 powder as an example. Results show that powder metallurgy processed WE43 results in comparable properties to those obtained from cast and wrought and offers potential for improvement.

Powder Metallurgy characteristics and application: state of the art

International Nuclear Information System (INIS)

Zaid, A.I.O.

2005-01-01

Powder metallurgy process (P/M) is a near-net or net-shape manufacturing process that combines the features of shape making technology of powder compaction with the development of final material and design properties (physical and mechanical) during subsequent densification or consolidation processes, e.g. sintering. It utilizes the metal powder or powders of metal alloys. In this paper, the major historical developments in P/M are reviewed and discussed. The main parameters involved in the process and their effects on the product characteristics are presented and discussed, which include: powders and methods of their production, particle size and shape, compressibility and additives, sintering temperature and time and finishing processes. The advantages and limitations of powder metallurgy are also presented and discussed. Finally, applications and future developments of the process are outlined and discussed. (author)

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.

Methods for production of aluminium powders and their application fields

International Nuclear Information System (INIS)

Gopienko, V.G.; Kiselev, V.P.; Zobnina, N.S.

1984-01-01

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

30 CFR 56.6901 - Black powder.

Science.gov (United States)

2010-07-01

... flame; (ii) Within any building in which a fuel-fired or exposed-element electric heater is operating...; and (4) Opened only when the powder is being transferred to a blasthole or another container and only in locations not listed in paragraph (b)(3) of this section. (c) Black powder shall be transferred...

30 CFR 57.6901 - Black powder.

Science.gov (United States)

2010-07-01

... feet of any magazine or open flame; (ii) Within any building in which a fuel-fired or exposed-element electric heater is operating; or (iii) In an area where electrical or incandescent-particle sparks could result in powder ignition; and (4) Opened only when the powder is being transferred to a blasthole or...

Permanent magnets and its production by powder metallurgy

Directory of Open Access Journals (Sweden)

Enrique Herraiz Lalana

2018-06-01

Full Text Available In this work, the historical relationship between permanent magnets and powder metallurgy is reviewed. Powder metallurgy is a manufacturing technique based on the compaction of powders that are sintered to create a solid product. This technique was used in the production of permanent magnets for the first time in the 18th century and, nowadays, most permanent magnetic materials are manufacturing by this mean. Magnetic properties are highly dependent on the microstructure of the final product, the magnetic alignment of domains and presence of porosity, to mention a few, and powder metallurgy enables fine control of these factors.

The preparation of UO2 powder: effect of ammonium uranate properties

International Nuclear Information System (INIS)

Woolfrey, J.L.

1978-01-01

Ammonium uranate (AU) powders were precipitated from a uranyl nitrate solution with gaseous ammonia. The decomposition of the powders in hydrogen was studied to determine those properties of AU which affect the decomposition reactions and influence the properties of the final UO 2 powder. The thermal decomposition was affected by the initial composition (ammonia and nitrate content) and the morphology of the AU powders. The amount of self-reduction increased with increasing combined ammonia content and decreased with increasing nitrate content. The specific surface area of the decomposed powder increased with increasing total ammonia content and initial surface area of the precursor AU powder. Thermal treatment of the decomposed powder can be used to modify such effects and, in commercial powder production, is used to control the properties of the final UO 2 powder. (Auth.)

Continuous Process for Low-Cost, High-Quality YSZ Powder

Energy Technology Data Exchange (ETDEWEB)

Scott L. Swartz; Michael Beachy; Matthew M. Seabaugh

2006-03-31

This report describes results obtained by NexTech Materials, Ltd. in a project funded by DOE under the auspices of the Solid-State Energy Conversion Alliance (SECA). The project focused on development of YSZ electrolyte powder synthesis technology that could be ''tailored'' to the process-specific needs of different solid oxide fuel cell (SOFC) designs being developed by SECA's industry teams. The work in the project involved bench-scale processing work aimed at establishing a homogeneous precipitation process for producing YSZ electrolyte powder, scaleup of the process to 20-kilogram batch sizes, and evaluation of the YSZ powder products produced by the process. The developed process involved the steps of: (a) preparation of an aqueous hydrous oxide slurry via coprecipitation; (b) washing of residual salts from the precipitated hydroxide slurry followed by drying; (c) calcination of the dried powder to crystallize the YSZ powder and achieve desired surface area; and (d) milling of the calcined powder to targeted particle size. YSZ powders thus prepared were subjected to a comprehensive set of characterization and performance tests, including particle size distribution and surface area analyses, sintering performance studies, and ionic conductivity measurements. A number of different YSZ powder formulations were established, all of which had desirable performance attributes relative to commercially available YSZ powders. Powder characterization and performance metrics that were established at the onset of the project were met or exceeded. A manufacturing cost analysis was performed, and a manufactured cost of $27/kg was estimated based on this analysis. The analysis also allowed an identification of process refinements that would lead to even lower cost.

Uranium Dioxide Powder Flow ability Improvement Using Sol-Gel

International Nuclear Information System (INIS)

Juanda, D.; Sambodo Daru, G.

1998-01-01

The improvement of flow ability characteristics of uranium dioxide powder has been done using sol-gel process. To anticipate a pellet mass production with uniform pellet dimension, the uranium dioxide powder must be have a spherical form. Uranium dioxide spherical powder has been diluted in acid transformed into sol colloidal solution. To obtain uranium dioxide spherical form, the uranium sol-colloidal solution has been dropped in a hot paraffin ( at the temperature of 90 0 C) to form gelatinous colloid and then dried at 800 0 C, and sintered at the temperature of 1700 0 C. The flow ability of spherical uranium dioxide powder has been examined by using Flowmeter Hall (ASTM. B. 213-46T). The measurement result reveals that the spherical uranium dioxide powder has a flow ability twice than that of unprocessed uranium dioxide powder

Dust generation in powders: Effect of particle size distribution

Directory of Open Access Journals (Sweden)

Chakravarty Somik

2017-01-01

Full Text Available 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. The variation of powder dustiness as a function of the particle size distribution was analysed for the powders, which were classified into three groups based on the fraction of particles within the respirable range. The trends we observe might be due to the interplay of several mechanisms like de-agglomeration and attrition and their relative importance.

OIL SOLUTIONS POWDER

Science.gov (United States)

Technical product bulletin: aka OIL SOLUTIONS POWDER, SPILL GREEN LS, this miscellaneous oil spill control agent used in cleanups initially behaves like a synthetic sorbent, then as a solidifier as the molecular microencapsulating process occurs.

High density UO2 powder preparation for HWR fuel

International Nuclear Information System (INIS)

Hwang, S. T.; Chang, I. S.; Choi, Y. D.; Cho, B. R.; Kwon, S. W.; Kim, B. H.; Moon, B. H.; Kim, S. D.; Phyu, K. M.; Lee, K. A.

1992-01-01

The objective of this project is to study on the preparation of method high density UO 2 powder for HWR Fuel. Accordingly, it is necessary to character ize the AUC processed UO 2 powder and to search method for the preparation of high density UO 2 powder for HWR Fuel. Therefore, it is expected that the results of this study can effect the producing of AUC processed UO 2 powder having sinterability. (Author)

Safe-geometry pneumatic nuclear fuel powder blender

International Nuclear Information System (INIS)

Lyon, W.L.

1979-01-01

The object of this invention is to provide a nuclear fuel powder mixing tank in which the powder can be rapidly and safely mixed and in which accumulation of critical amounts of fuel is prevented. (UK)

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.

Pressurized Anneal of Consolidated Powders

Science.gov (United States)

Nemir, David Charles (Inventor); Rubio, Edward S. (Inventor); Beck, Jan Bastian (Inventor)

2017-01-01

Systems and methods for producing a dense, well bonded solid material from a powder may include consolidating the powder utilizing any suitable consolidation method, such as explosive shockwave consolidation. The systems and methods may also include a post-processing thermal treatment that exploits a mismatch between the coefficients of thermal expansion between the consolidated material and the container. Due to the mismatch in the coefficients, internal pressure on the consolidated material during the heat treatment may be increased.

Transport device for nuclear fuel powder

International Nuclear Information System (INIS)

Adelmann, M.

1987-01-01

The transport device for nuclear fuel powder, which does not disintegrate during transport, has a transport pipe which starts with its entry end from the floor or a closed container and opens with its outlet end at the top into a closed separation container connect via a powder filter to a suction pump. By alternate regular opening and closing of a first control valve for transport gas fitted to a transport pipe to a supply duct and a second control valve for transport gas fitted to the container to an additional supply duct, alternating plugs of nuclear fuel powder and transport gas cushions are formed and are transported to the outlet end of the transport pipe. (orig./HP) [de

Numerical analysis of air effect on the powder flow dynamics in the FT4 Powder Rheometer

Directory of Open Access Journals (Sweden)

Nan Wenguang

2017-01-01

Full Text Available The FT4 powder rheometer of Freeman Technology is widely used nowadays in industry for characterisation of particle flow under dynamic conditions of shear strain rate. It measures the work (termed flow energy required to penetrate a rotating impeller into a powder bed. However, little is known about its underlying powder mechanics, i.e. the relationship between the flow energy and the prevailing local shear stress. This has recently been studied, but only for very simple and ideal systems amenable to analysis by DEM. We analyse the effect of gas flow through the powder bed on the flow behaviour of cohesionless particles in FT4 by DEM-CFD simulation. The results show that the relative particle velocities induced by the mean shear speed, is of the same order as that produced by the root of granular temperature. The shear stress in both cases with and without gas flow could be quantified by the inertial number. The flow energy correlates well with the shear stress in front of the blade, and both increase with the inertial number and could be significantly reduced by the upward gas flow.

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.

Compactibility of atomized high-speed steel and steel 3 powders

International Nuclear Information System (INIS)

Kulak, L.D.; Gavrilenko, A.P.; Pikozh, A.P.; Kuz'menko, N.N.

1985-01-01

Spherical powders and powders of lammellar-scaly shape of high-speed R6M5K5 steel and steel 3 produced by the method of centrifugal atomization of a rotating billet under conditions of cold pressing in steel moulds are studied for thier compactability. Compacting pressure dependnences are establsihed for density of cold-pressed compacts of spherical and scaly powders. The powders of lammellar-scaly shape both of high-speed steel and steel 3 are found to possess better compactibility within a wide range of pressures as compared to powders of spherical shape. Compacts of the lammellar-scaly powders possess also higher mechanical strength

Process for fabricating mixed-oxide powders

International Nuclear Information System (INIS)

Elmaleh, D.; Giraudel, A.

1975-01-01

A physical-chemical process for fabricating homogeneous powders suitable for sintering is described. It can be applied to the synthesis of all mixed oxides having mutually compatible and water soluble salts. As a specific example, the fabrication of lead titanate-zirconate powders used to make hot pressed ceramics is described. These ceramics show improved piezoelectric properties [fr

Whey powder sterilization by ionizing irradiation

International Nuclear Information System (INIS)

Todorovic, M.; Salatic, Z.; Markov, S.

1988-01-01

Whey powder was sterilized by gamma waves application. As a source of irridiation isotope 60Co was used in Institute of Nuclear sciences B oris Kidrich , Vincha-Belgrade (Yugoslavia). The applied doses were: a, b, c, d, and e Kgy. The dose d was radappertization. After whey powder irradiation no adverse changes of organoleptic properties were noticed

Sysnthesis of powders by freeze-drying

International Nuclear Information System (INIS)

Johnson, S.M.; Gusman, M.I.; Hildenbrand, D.L.

1988-01-01

The freeze-drying method of synthesizing powders of the superconducting oxide YBa 2 Cu 3 O 7 - δ is described. This process produces homogeneous, submicron powders of high purity. The effects of salt selection, solution concentration and pH on the process are described. Some evaluation of the sintering behavior and the effects on critical current density are included

Tricalcium phosphate powder: Preparation, characterization and compaction abilities

Directory of Open Access Journals (Sweden)

Abida Fatima

2017-02-01

Full Text Available In this work, we characterize tricalcium phosphate powders Ca9(HPO4(PO45(OH resulting from a reaction between calcium hydroxide and orthophosphoric acid at room temperature, without pH adjustment and in absence of ionic impurities. The prepared powder has an atomic ratio Ca/P of 1.512 ± 0.005. The real density is 2.68 ± 0.02 g/cm3 and the specific surface area is 80 ± 02 m2/g. During compression, the microstructure of Ca-deficient apatite powder with the presence of HPO4 groups seems to support the cohesion between particles. The transmission ratio is 90%, the transfer ratio is 41.8 and the ratio of the die-wall friction is 0.22. These results show that apatitic tricalcium powder gives a good aptitude to the compaction which leads to a good tensile strength (0.79 MPa. The heat treatment of the prepared powder shows the precise temperature for the formation of pyrophosphate, β-TCP and α-TCPa phases.  The purity and aptitude to compaction of the prepared powders are very promising for pharmaceutical and medical applications.

Synthesis of ITO Powder by Dry Process and Lifetime Characteristics of the ITO Target Fabricated with its Powder

Science.gov (United States)

Takahashi, Seiichiro; Itoh, Hironori; Komatsu, Ryuichi

Lifetime of an indium tin oxide (ITO) target is an important characteristic in the production of liquid crystal displays (LCDs). Increasing the sintering density of the ITO target is assumed to lead to an increased lifetime. So far, it has been clarified that the carbon concentration in In2O3 powder, the raw material of ITO targets, influences remarkably the target lifetime. In this study, with the aim of reducing the concentration of carbon in In2O3 powder, the synthesis of In2O3 powder containing dissolved Sn by a dry process was performed.

The effect of particle structure on apparent density of electrolytic copper powder

Directory of Open Access Journals (Sweden)

K. I. POPOV

2001-12-01

Full Text Available The quantitative microstructural analysis and the sieve analysis of copper powder as well as the scanning electron microscopy analysis of the copper powders particles were performed. It was found that the structure of the copper powder particles determines the apparent density of copper powder. The powder particles from the same fractions of different powders occupy approximately the same volume, but the structure of metallic copper is very different. This causes the difference in apparent densities of copper powder obtained under different conditions. The more dendritic is the structure of powder particles the smaller is the apparent density of copper powder.

Confirmation test of powder mixing process in J-MOX

International Nuclear Information System (INIS)

Ota, Hiroshi; Osaka, Shuichi; Kurita, Ichiro

2009-01-01

Japan Nuclear Fuel Ltd. (hereafter, JNFL) MOX Fuel Fabrication Plant (hereafter, J-MOX) is what fabricates MOX fuel for domestic light water power plants. Development of design concept of J-MOX was started mid 90's and the frame of J-MOX process was clarified around 2000 including adoption of MIMAS process as apart of J-MOX powder process. JNFL requires to take an answer to any technical question that has not been clarified ever before by world's MOX and/or Uranium fabricators before it commissions equipment procurement. J-MOX is to be constructed adjacent to the Rokkasho Reprocessing Plant (RRP) and to utilize MH-MOX powder recovered at RRP. The combination of the MIMAS process and the MH-MOX powder is what has never tried in the world. Therefore JNFL started a series of confirmation tests of which the most important is the powder test to confirm the applicability of MH-MOX powder to the MIMAS process. The MH-MOX powder, consisting of 50% plutonium oxide and 50% uranium oxide, originates JAEA development utilizing microwave heating (MH) technology. The powder test started with laboratory scale small equipment utilizing both uranium and the MOX powder in 2000, left a solution to tough problem such as powder adhesion onto equipment, and then was followed by a large scale equipment test again with uranium and the MOX powder. For the MOX test, actual size equipment within glovebox was manufactured and installed in JAEA plutonium fuel center in 2005, and based on results taken so far an understanding that the MIMAS equipment, with the MH-MOX powder, can present almost same quality MOX pellet as what is introduced as fabricated in Europe was developed. The test was finished at the end of Japanese fiscal year (JFY) 2007, and it was confirmed that the MOX pellets fabricated in this test were almost satisfied with the targeted specifications set for domestic LWR MOX fuels. (author)

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.

RF induction plasma spheroidization of tungsten powders

International Nuclear Information System (INIS)

Gu Zhogntao; Ye Gaoying; Liu Chuandong; Tong Honghui

2009-01-01

Irregularly-shaped tungsten powders (average granular sizes of 512 μm) have been spheroidized by radio frequency (RF)induction plasma. The effects of feed rate, mode of material dispersion, particle size on spheroidization efficiency are investigated. Experimental results show that the spheroidization efficiency decreases rapidly when the feed rate increases to more than 95 g/min. Only 30% spheroidization efficiency is gained at the feed rate of 135.75 g/min. The spheroidization efficiency is also affected by the flow rate of carrier gas. When the flow rate of carrier gas is 0.12 m 3 /h, the dispersion effect is the best, and the spheroidization efficiency is almost 100%. The apparent density of tungsten powders increases a bit with the increase of spheroidization efficiency. And the particle size uniformity of spheroidized tungsten powders is in accordance with that of original powders. (authors)

Synthesis of battery grade reduced silver powder

International Nuclear Information System (INIS)

Qadeer, R.; Hameed, M.; Ikram, S.; Munir, A.

2002-01-01

Process for production of battery grade reduced silver powder, an active positive material for zinc-silver oxide batteries, having specific characteristics has been optimized and the synthesized reduced silver powder was characterized. Results reveal that the values of bulk density (1.25 0.1 g/cm3) and activity (73.27 %) of synthesized reduced silver powder lies within the recommended range for use as battery material. It has purity ≥ 98% and contains Fe and Cu as traces in the concentration range of 30 5 ppm and 15 7 ppm respectively. Others determined values of surface and pores parameters are: surface area 2.6 .4 m2/g: pore volume 3.10 cm3/g: pore diameter 0.043 mu m and porosity 20%. XRD studies reveal that reduced silver powder has a cubic structure. (author)

Heat Treatment of Gas-Atomized Powders for Cold Spray Deposition

Science.gov (United States)

Story, William A.; Brewer, Luke N.

2018-02-01

This communication demonstrates the efficacy of heat treatment on the improved deposition characteristics of aluminum alloy powders. A novel furnace was constructed for solutionizing of feedstock powders in an inert atmosphere while avoiding sintering. This furnace design achieved sufficiently high cooling rates to limit re-precipitation during powder cooling. Microscopy showed homogenization of the powder particle microstructures after heat treatment. Cold spray deposition efficiency with heat-treated powders substantially increased for the alloys AA2024, AA6061, and AA7075.

Nanograin formation in milled MoO3 powders

International Nuclear Information System (INIS)

Guerrero-Paz, J; Dorantes-Rosales, H; Aguilar-Martínez, J A; Garibay-Febles, V

2013-01-01

Powder of Molybdenum trioxide was milled for different times in horizontal ball mills. Such powder was characterized by TEM and XRD. Powder was rapidly de-agglomerated and fragmented up to attain nanoplates of two types, amorphous and crystalline. Finally, cold-welding of nanoplates occurred permitting some relaxation process to obtain a more stable energized structure consisting of equiaxial crystalline nanograins after 16 hours of milling.

Rapidly solidified prealloyed powders by laser spin atomization

Science.gov (United States)

Konitzer, D. G.; Walters, K. W.; Heiser, E. L.; Fraser, H. L.

1984-01-01

A new technique, termed laser spin atomization, for the production of rapidly solidified prealloyed powders is described. The results of experiments involving the production of powders of two alloys, one based on Ni, the other on Ti, are presented. The powders have been characterized using light optical metallography, scanning electron microscopy, energy dispersive X-ray spectroscopy, and Auger elec-tron spectroscopy, and these various observations are described.

Measurement of agglomerate strength distributions in agglomerated powders

International Nuclear Information System (INIS)

Ciftcioglu, M.; Aking, M.; Burkhart, L.

1986-01-01

Strength distributions of particle agglomerates in six different yttria powders were measured using a calibrated ultrasonic sound field. The density of sintered pellets was directly related to the agglomerate strength of each powder. No systematic relation to the sintered density was observed for bulk densities or pressure-density compaction data for the loose powders, or for pore size distributions or green densities for the pressed compacts

Ninety Years of Powder Diffraction: from Birth to Maturity

International Nuclear Information System (INIS)

Paszkowicz, W.

2006-01-01

The expression ''powder diffraction '' denotes the phenomenon of diffraction of any electromagnetic waves or particles on polycrystalline (powdered, bulk or thin film) materials which is used in a wide variety experimental settings. The X-ray powder-diffraction method was devised and developed during the First World War (1916) by a Dutch/Swiss team, Peter Debye and Paul Scherrer, in Goettingen, Germany, and independently, marginally later, by an American, Albert W. Hull in Schenectady, USA. The birth of powder diffraction came four years after the discovery of the phenomenon of single-crystal diffraction made in 1912 by Walther Friedrich, Paul Knipping and Max Laue in Munich and developed from 1912/1913 by William Henry Bragg (father) and William Lawrence Bragg (son), and later by many others. Powder diffraction became a milestone towards an understanding of the nature of materials, especially of those which cannot be prepared in the form of suitable single crystals, and permitted rapid progress in solid state physics and chemistry. The events leading to the discovery of powder-diffraction phenomenon are briefly reviewed. The importance of synchrotron powder diffraction studies, which have developed since 1980s, is emphasised. (author)

Preparation of reactive and refractory metal powders (Paper No. 25)

International Nuclear Information System (INIS)

Sundaram, C.V.; Sharma, B.P.; Krishnan, T.S.

1979-01-01

In devising processes for the preparation of refractory and reactive metal powders, one has to reckon with many relevant factors. The choice of specific flowsheets is governed by the characteristics of the metal compounds and the reducing agents, the purity required and achievable in the as-reduced powder, the need for further refining of the metal, the possibilities of chemical/physical/mechanical comminution of the purified metal without contamination, and the end application of the powder metal. Micron size zirconium powder used as trigger material in photo-flash bulbs and detonator compositions, tantalum powder of controlled particle size and high purity for the production of electrolytic capacitors, and beryllium metal powder for the preparation of hot pressed powder metallurgy components are illustrative of the variety of reactive metal powders for industrial applications. The work carried out at the Bhabha Atomic Research Centre, Bombay, on the preparation of special metal powders, with particular emphasis on Group IV and V metals and also beryllium is presented. Reduction of metal oxides with alkaline earth metals/hydrides, reduction of metal halides with sodium/magnesium, vacuum arc and electron beam melt purification followed by comminution by hydrogen embrittlement/mechanical comminution are among the processes discussed. (auth.)

POWDER COAT APPLICATIONS

Science.gov (United States)

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

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.

Comparative studies of industrial grade carbon black powders

Energy Technology Data Exchange (ETDEWEB)

Chawla, Komal, E-mail: komalchawla.rs@gmail.com; Chauhan, Alok P. S., E-mail: chauhan.alok@gmail.com, E-mail: alok.chauhan@alumni.stonybrook.edu [Department of Physics and Material Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida-201307, UP, India. (India)

2016-05-06

Comparative studies of two dissimilar industrial grade Carbon Black (CB) powders (N375 and N405) were conducted. The structure, surface area and particle size are the three important characteristics of CB powder that determine their processability and application as filler in preparing rubber compounds. The powders were characterized for their structure using dibutyl phthalate absorption (DBPA), particle size via laser particle size analyzer and surface area by nitrogen adsorption method. The structural characterization showed that N405 had lower DBPA in comparison to N375, confirming low structure of N405 grade CB powder. It was observed from the particle size analysis that N375 was coarser than N405 grade CB. The total surface area values were determined by the BET method based on the cross sectional area of the nitrogen molecule. N375, a coarse grade CB powder with high structure, depicted less surface area as compared to N405.

The use of glass powder in making batako

Science.gov (United States)

Nursyamsi, N.; Indrawan, I.

2018-02-01

Along with the increase in construction materials, innovation is needed to lessen the use of them, and one of them is by using cement [1]. In this research, it is reduced by glass powder; the reason for using it as the substitution of cement is that some chemical elements in cement are similar to those in glass powder such as SiO2, A12o3, Fe2O3, and CaO. The glass powder used was the one who passed sieve no. 100 and was hampered in sieve no. 200. It passed sieve no. 200 with its composition of 0%, 10%, 15%, 20%, 25%, and 30% from the volume of the use of cement. The specimen would treat within 28 days before the testing of compressive strength, water absorption, and tensile strength [2]. The variation which produced optimum result would mix with the foaming agent as the material for reducing the weight of the specimen. After that, the test of compressive strength, water absorption, and tensile strength on the installment of batako walls were done. The data analyzed by using SNI 02-0349-1989[3] reference about concrete brick for wall installment. The variation of 20% of glass powder passing sieve no. 200 gave optimum result. A specimen of the variation on glass powder of 20% which passed sieve no. 200 and the foaming agent was higher than the compressive strength of the specimen which used glass powder substitution of 0% of passing sieve no. 200 and foaming agent. The compressive strength of batako walls which used the batako construction with glass powder substitution of 20% of passing sieve no. 200 and the foaming agent was also higher than the compressive strength of the assaying object which used glass powder substitution of 0% of passing sieve no. 200 and foaming agent.

Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

Science.gov (United States)

Whitman, Pamela K.; Feke, Donald L.

1986-01-01

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

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% ...

Peculiarities of powder metallurgy of vanadium and its alloys

International Nuclear Information System (INIS)

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

1987-01-01

Literature data on preparation of vanadium powder and powder materials on the vanadium base are generalized. Application of powder metallurgy engineering, allowing simulaneously to introduce practically any strengthening and solid-lubricating components as well as to alloy vanadium, permits undoubtedly to develop composite materials on the vanadium base

Set up of Uranium-Molybdenum powder production (HMD process)

International Nuclear Information System (INIS)

Lopez, Marisol; Pasqualini, Enrique E.; Gonzalez, Alfredo G.

2003-01-01

Powder metallurgy offers different alternatives for the production of Uranium-Molybdenum (UMo) alloy powder in sizes smaller than 150 microns. This powder is intended to be used as a dispersion fuel in an aluminum matrix for research, testing and radioisotopes production reactors (MTR). A particular process of massive hydriding the UMo alloy in gamma phase has been developed. This work describes the final adjustments of process variables to obtain UMo powder by hydriding-milling-de hydriding (HMD) and its capability for industrial scaling up. (author)

Laser Processing Technology using Metal Powders

Energy Technology Data Exchange (ETDEWEB)

Jang, Jeong-Hwan; Moon, Young-Hoon [Pusan National University, Busan (Korea, Republic of)

2012-03-15

The purpose of this paper is to review the state of laser processing technology using metal powders. In recent years, a series of research and development efforts have been undertaken worldwide to develop laser processing technologies to fabricate metal-based parts. Layered manufacturing by the laser melting process is gaining ground for use in manufacturing rapid prototypes (RP), tools (RT) and functional end products. Selective laser sintering / melting (SLS/SLM) is one of the most rapidly growing rapid prototyping techniques. This is mainly due to the processes's suitability for almost any materials, including polymers, metals, ceramics and many types of composites. The interaction between the laser beam and the powder material used in the laser melting process is one of the dominant phenomena defining feasibility and quality. In the case of SLS, the powder is not fully melted during laser scanning, therefore the SLS-processed parts are not fully dense and have relatively low strength. To overcome this disadvantage, SLM and laser cladding (LC) processes have been used to enable full melting of the powder. Further studies on the laser processing technology will be continued due to the many potential applications that the technology offers.

Synthesis of Cu-coated Graphite Powders Using a Chemical Reaction Process

Energy Technology Data Exchange (ETDEWEB)

Jang, Jun-Ho; Park, Hyun-Kuk; Oh, Ik-Hyun [Korea Institute of Industrial Technology (KITECH), Gwangju (Korea, Republic of); Lim, Jae-Won [Chonbuk National University, Jeonju (Korea, Republic of)

2017-05-15

In this paper, Cu-coated graphite powders for a low thermal expansion coefficient and a high thermal conductivity are fabricated using a chemical reaction process. The Cu particles adhere to the irregular graphite powders and they homogeneously disperse in the graphite matrix. Cu-coated graphite powders are coarser at approximately 3-4 μm than the initial graphite powders; furthermore, their XRD patterns exhibit a low intensity in the oxide peak with low Zn powder content. For the passivation powders, the transposition solvent content has low values, and the XRD pattern of the oxide peaks is almost non-existent, but the high transposition solvent content does not exhibit a difference to the non-passivation treated powders.

Slow stress relaxation behavior of cohesive powders

NARCIS (Netherlands)

Imole, Olukayode Isaiah; Paulick, Maria; Magnanimo, Vanessa; Morgenmeyer, Martin; Ramaioli, Marco; Chavez Montes, Bruno E.; Kwade, Arno; Luding, Stefan

2016-01-01

We present uniaxial (oedometric) compression tests on two cohesive industrially relevant granular materials (cocoa and limestone powder). A comprehensive set of experiments is performed using two devices – the FT4 Powder Rheometer and the custom made lambdameter – in order to investigate the

Synthesis and characterization of superconducting YBCO powder

International Nuclear Information System (INIS)

Praveen, B.; Karki, T.; Krishnamoorthi, J.

2008-01-01

Full text: Superconducting yttrium barium copper oxide power has been synthesized through solid state sintering method - milling and sintering - using Y 2 O 3 , BaCo 3 and CuO powders. XRD result of the milled and sintered powder reveals that the powder that has formed contains YBa 2 Cu 3 O 6.5 superconducting phase. Results obtained by SEM/EDAX show the distribution of the different elements. Experiments carried out by intermediate firing and final annealing in oxygen controlled atmosphere show the diffusion of oxygen in preformed YBa 2 Cu 3 O 6.5 and their results are discussed

Hydrogen solubility in FLiNaK mixed with titanium powder

International Nuclear Information System (INIS)

Yagi, Juro; Sagara, Akio; Watanabe, Takashi; Tanaka, Teruya; Takayama, Sadatsugu; Muroga, Takeo

2015-01-01

Highlights: • The hydrogen solubility in a FLiNaK mixed with Ti powder was investigated. • A significant increase in hydrogen solubility was observed. • Controlling the purity of the molten salt was found to be one of the key issues. • A vanadium alloy would be compatible with the Ti powder/molten salt mixture. - Abstract: The hydrogen solubility in a FLiNaK molten salt mixed with Ti powder was investigated. A hydrogen-soluble metal powder mixed with a molten salt can increase the effective hydrogen solubility of the molten salt, which is currently a major disadvantage of molten salts. A significant increase in hydrogen solubility was observed, even with a mass fraction of Ti powder of only 0.1 wt%. The increase of hydrogen solubility was so large that a vanadium alloy would be compatible with the Ti powder/molten salt mixture, unlike typical molten salts that result in an unacceptably large tritium inventory in the vanadium alloy. In addition, contamination of the Ti powder by oxidation suppressed the hydrogen uptake and release capability. Controlling the purity of the molten salt was found to be one of the key issues for the metal powder mixture concept.

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.

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).

Sanitation of onion powder by irradiation and heating

Energy Technology Data Exchange (ETDEWEB)

Delkinova, S M [Bulgarplod, Plovdiv (Bulgaria); Dupuy, P [Institut National de Recherches Agronomiques (INRA), 21 - Dijon (France). Station de Recherches sur les Aliments de l' Homme

1973-01-01

Onion powder is frequently contaminated by a mesophile bacterial flora containing some spore-forming strains. Heating is not an admissible method of sterilization in this case, because of the volatile aromatic substances formed by the enzyme system present. After irradiation with 0.8 Mrad the surviving microbial flora contained Clostridium, Bacillus, Enterococcus and Micrococcus strains. These Micrococcus strains are less resistant than M.radiodurans and do not develop as spoilage organisms in foods. During the months following irradiation no growth was observed, on the contrary the number of cells surviving diminished in the same way both in the irradiated and the untreated samples. In soup powders with short cooking time, if the irradiated or untreated onion powder is added after boiling, a chance is caused by the growth of Lactobacillus or Bacillus strains. A radiation treatment with 0.4 Mrad gives a sterile soup, when boiled for 5 minutes. In meat pastes the most dangerous microbial flora is that consisting mainly of spora-forming anaerobic bacteria. It was shown that if the pasta was aromatized with onion powder treated with 0.2 Mrad before cooking, no growth occurred. The control sample containing untreated onion powder was spoiled by a microbial flora dominated by spore-forming aerobic bacteria. These two experiments proved that onion powder can be decontaminated by treatment with 0.2 or 0.4 Mrad. It is known that this dose has no detrimental effect on the organoleptic quality of the onion powder and the cost of irradiation is compatible with the price of the product treated. (F.J.)

Preparation of nanosize carbon powders by pulsed wire discharge

Energy Technology Data Exchange (ETDEWEB)

Minami, C.; Kinemuchi, Y.; Suzuki, T.; Suematsu, H.; Jiang, W.; Yatsui, K. [Nagaoka Univ. of Technology, Extreme Energy-Density Research Inst., Nagaoka, Niigata (Japan); Hirata, T.; Hatakeyama, R. [Tohoku Univ., Graduate School of Engineering, Sendai, Miyagi (Japan)

2002-06-01

Nanosize powders of carbons were tried to be synthesized by pulsed discharge of graphite wires in several kinds of ambient gases. When the wire was discharged in N{sub 2} gas, nanosize powders have been successfully produced. The result of X-ray diffraction analysis indicated that nanosize powders produced in N{sub 2} gas at 750 Torr were amorphous carbon containing glassy carbons, while mass-spectrum analysis demonstrated the production of fullerenes at 600 Torr. If the wire is discharged in Ar gas, dielectric breakdown takes place between electrodes, producing no carbon powders. (author)

Microstructural properties of electrochemically prepared Ni–Fe–W powders

International Nuclear Information System (INIS)

Ribić-Zelenović, L.; Ćirović, N.; Spasojević, M.; Mitrović, N.; Maričić, A.; Pavlović, V.

2012-01-01

A nanostructured Ni–Fe–W powder was obtained by electrodeposition from ammonium citrate electrolyte within the current density range of 500–1000 mA cm −2 at the electrolyte temperature of 50 °C–70 °C. XRD analysis shows that the powder contains an amorphous matrix having embedded nanocrystals of the FCC solid solution of iron and tungsten in nickel, with an average crystal grain size of 3.4 nm, a high internal microstrain value and a high density of chaotically distributed dislocations. EDS analysis exhibits that the chemical composition of the Ni–24%Fe–11%W powder does not depend upon current density and electrolyte temperature due to the diffusion control of the process of codeposition of nickel, iron and tungsten. SEM micrographs show that the electrodeposition results in the formation of two particle shapes: large cauliflower-like particles and small dendrite particles. The cauliflower-like particles contain deep cavities at hydrogen evolution sites. Cavity density increases with increasing deposition current density. Smaller powder particles are formed at higher temperatures and at higher current densities. During the first heating, relative magnetic permeability decreases reaching the Curie temperature at about 350 °C and after cooling exhibits a 12% increase due to the performed relaxation process. Following the second heating to 500 °C, the magnetic permeability of the powder is about 5% lower than that of the as-prepared powder due to crystallization of the amorphous phase of the powder and the crystal grain growth in FCC phase. - Highlights: ► Electrodeposition Ni–Fe–W powder from ammonium citrate electrolyte (500–1000 mA cm −2 ). ► Powder contains amorphous matrix and embedded nanocrystals 3.4 nm. ► Chemical composition Ni–24%Fe–11%W do not depend upon current density and electrolyte temperature. ► Two particle shapes: large cauliflower-like particles and small dendrite particles. ► Smaller powder particles are

Microstructural properties of electrochemically prepared Ni-Fe-W powders

Energy Technology Data Exchange (ETDEWEB)

Ribic-Zelenovic, L. [Faculty of Agronomy, University of Kragujevac, Cacak (Serbia); Cirovic, N. [Joint Laboratory for Advanced Materials of SASA, Technical Faculty Cacak, University of Kragujevac, Cacak (Serbia); Spasojevic, M. [Faculty of Agronomy, University of Kragujevac, Cacak (Serbia); Mitrovic, N., E-mail: nmitrov@tfc.kg.ac.rs [Joint Laboratory for Advanced Materials of SASA, Technical Faculty Cacak, University of Kragujevac, Cacak (Serbia); Maricic, A. [Joint Laboratory for Advanced Materials of SASA, Technical Faculty Cacak, University of Kragujevac, Cacak (Serbia); Pavlovic, V. [Faculty of Agriculture, University of Belgrade, Belgrade (Serbia)

2012-07-16

A nanostructured Ni-Fe-W powder was obtained by electrodeposition from ammonium citrate electrolyte within the current density range of 500-1000 mA cm{sup -2} at the electrolyte temperature of 50 Degree-Sign C-70 Degree-Sign C. XRD analysis shows that the powder contains an amorphous matrix having embedded nanocrystals of the FCC solid solution of iron and tungsten in nickel, with an average crystal grain size of 3.4 nm, a high internal microstrain value and a high density of chaotically distributed dislocations. EDS analysis exhibits that the chemical composition of the Ni-24%Fe-11%W powder does not depend upon current density and electrolyte temperature due to the diffusion control of the process of codeposition of nickel, iron and tungsten. SEM micrographs show that the electrodeposition results in the formation of two particle shapes: large cauliflower-like particles and small dendrite particles. The cauliflower-like particles contain deep cavities at hydrogen evolution sites. Cavity density increases with increasing deposition current density. Smaller powder particles are formed at higher temperatures and at higher current densities. During the first heating, relative magnetic permeability decreases reaching the Curie temperature at about 350 Degree-Sign C and after cooling exhibits a 12% increase due to the performed relaxation process. Following the second heating to 500 Degree-Sign C, the magnetic permeability of the powder is about 5% lower than that of the as-prepared powder due to crystallization of the amorphous phase of the powder and the crystal grain growth in FCC phase. - Highlights: Black-Right-Pointing-Pointer Electrodeposition Ni-Fe-W powder from ammonium citrate electrolyte (500-1000 mA cm{sup -2}). Black-Right-Pointing-Pointer Powder contains amorphous matrix and embedded nanocrystals 3.4 nm. Black-Right-Pointing-Pointer Chemical composition Ni-24%Fe-11%W do not depend upon current density and electrolyte temperature. Black

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 ...

The effect of reduced oxygen content powder on the impact toughness of 316 steel powder joined to 316 steel by low temperature HIP

International Nuclear Information System (INIS)

Lind, Anders; Sundstroem, Johan; Peacock, Alan

2005-01-01

During the manufacture of the blanket modules, 316L steel powder is simultaneously consolidated and joined to tubes and blocks of 316L materials by hot isostatic pressing (HIP). The high processing temperature can detrimentally increase the grain size of the water-cooling tubes in the structure and the blocks reducing their strength. It is well known [L. Arnberg, A. Karlsson, Influence of powder surface oxidation on some properties of a HIPed martensitic chromium steel, Int. J. Powder Metall. 24 (2) (1988) 107-112] that surface oxides on the powder particles negatively influence the impact toughness of material and joints consolidated in this way. At a high HIP temperature, the oxides are at least partly transformed, thereby improving the impact toughness [L. Nyborg, I. Olefjord, Surface analysis of PM martensitic steel before and after consolidation. Part 2. Surface analysis of compacted material, Powder Metall. 31 (1) (1988) 40-44]. In order to get acceptable mechanical properties of materials produced at a low HIP temperature, the oxygen content on the powder surfaces needs to be reduced. In order to study the effect of reducing the powder oxygen content, it was reduced and the results were compared to those of specimens with ordinary oxygen content. The effect on the impact toughness and the tensile strength of low temperature (1020 and 1060 deg. C) HIP joints between steel blocks and powder consolidated material with low and ordinary oxygen content was measured

Pharmaceutical powder compaction technology

National Research Council Canada - National Science Library

Çelik, Metin

2011-01-01

... through the compaction formulation process and application. Compaction of powder constituents both active ingredient and excipients is examined to ensure consistent and reproducible disintegration and dispersion profiles...

Micro-powder injection moulding of tungsten

International Nuclear Information System (INIS)

Zeep, B.

2007-12-01

For He-cooled Divertors as integral components of future fusion power plants, about 300000 complex shaped tungsten components are to be fabricated. Tungsten is the favoured material because of its excellent properties (high melting point, high hardness, high sputtering resistance, high thermal conductivity). However, the material's properties cause major problems for large scale production of complex shaped components. Due to the resistance of tungsten to mechanical machining, new fabrication technologies have to be developed. Powder injection moulding as a well established shaping technology for a large scale production of complex or even micro structured parts might be a suitable method to produce tungsten components for fusion applications but is not yet commercially available. The present thesis is dealing with the development of a powder injection moulding process for micro structured tungsten components. To develop a suitable feedstock, the powder particle properties, the binder formulation and the solid load were optimised. To meet the requirements for a replication of micro patterned cavities, a special target was to define the smallest powder particle size applicable for micro-powder injection moulding. To investigate the injection moulding performance of the developed feedstocks, experiments were successfully carried out applying diverse cavities with structural details in micro dimension. For debinding of the green bodies, a combination of solvent debinding and thermal debinding has been adopted for injection moulded tungsten components. To develop a suitable debinding strategy, a variation of the solvent debinding time, the heating rate and the binder formulation was performed. For investigating the thermal consolidation behaviour of tungsten components, sinter experiments were carried out applying tungsten powders suitable for micro-powder injection moulding. First mechanical tests of the sintered samples showed promising material properties such as a

An application of powder metallurgy to dentistry.

Science.gov (United States)

Oda, Y; Ueno, S; Kudoh, Y

1995-11-01

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

Ultrasonic assisted hot metal powder compaction.

Science.gov (United States)

Abedini, Rezvan; Abdullah, Amir; Alizadeh, Yunes

2017-09-01

Hot pressing of metal powders is used in production of parts with similar properties to wrought materials. During hot pressing processes, particle rearrangement, plastic deformation, creep, and diffusion are of the most effective powder densification mechanisms. Applying ultrasonic vibration is thought to result in great rates of densification and therefore higher efficiency of the process is expected. This paper deals with the effects of power ultrasonic on the densification of AA1100 aluminum powder under constant applied stress. The effects of particle size and process temperature on the densification behavior are discussed. The results show that applying ultrasonic vibration leads to an improved homogeneity and a higher relative density. Also, it is found that the effect of ultrasonic vibration is greater for finer particles. Copyright © 2016 Elsevier B.V. All rights reserved.

Method of solidifying powderous wastes

International Nuclear Information System (INIS)

Kakimoto, Akira; Miyake, Takashi; Sato, Shuichi; Inagaki, Yuzo.

1985-01-01

Purpose: To improve the properties of solidification products, in the case of solidifying powderous wastes with thermosetting resins. Method. A solvent for the solution of the thermosetting resin is admixed with the powderous wastes into a paste-like form prior to adding the resin to the wastes, which are then mixed with the resin solution. As the result, those solidification products having the specific gravity and the compression strength more excellent than those of the conventional ones, and much higher than the reference values can be obtained. (Kamimura, M.)

Operation whey powder. Anatomy of a German scandal

Energy Technology Data Exchange (ETDEWEB)

Brunner, E

1987-04-03

The odyssey of the contaminated whey powder finally has come to an end, and the 5000 tonnes of whey now are designated for decontamination by means of an ion exchange technique. The article throws light upon the political and economic reasons that sent the whey powder off on a chaotic journey. It is worth mentioning in this context that the natural radioactivity of inorganic fertilizers is much higher than that of the whey powder in question.

Exploring Oven-drying Technique in Producing Pineapple Powder

OpenAIRE

Cyril John A. Domingo; Wilma M. De Vera; Raquel C. Pambid

2017-01-01

Pineapple puree and juice of 11 to 12 °Brix were used to obtain pineapple powder using oven-drying technique. Addition of maltodextrin in treatments 2 and 4 yielded good quality powder, however addition of sugar and maltodextrin in treatments 1 and 3 resulted to sticky product which was processed to pineapple leather. Treatment 2 composed of pineapple puree and maltodextrin resulted to significantly higher powder recovery compared with treatment 4 which composed of pineapple juice...

Processing of tungsten csrap into powders by electroerosion dispersion

International Nuclear Information System (INIS)

Fominskij, L.P.; Myuller, A.S.; Levchuk, M.V.; Tarabrina, V.P.

1985-01-01

A powder produced by electroerosion dispersion in water from tungsten chips and rod cuttings is studied for its properties and structure. Powder particles are mainly of spherical shape, their predominant size is 2-4 μm. A fraction of -63 μm comprises a basic mass of the powder (up to 80%), an ultrafine (to 40 μm) phase of WO which is isolated by decantation comprises about 3.5% of its mass. The powder particles are low oxidized, have a fine-grain microstructure and consist of tungsten with admixture of β-W (to 30%). A fraction of total oxygen mass in the mixture of fractio s 0.74%. The powder containing less than 0.25% of oxygen is produced by decantation of the oxide phase. The product purity is determined exclusively by the purity of the raw material. Prior to producing articles it is recommended to anneal the powder either in the inert atmosphere or in the reduced medium at 750 deg C for β-W to transfer into common tungsten

Application of acid-modified Imperata cylindrica powder for latent fingerprint development.

Science.gov (United States)

Low, Wei Zeng; Khoo, Bee Ee; Aziz, Zalina Binti Abdul; Low, Ling Wei; Teng, Tjoon Tow; bin Abdullah, Ahmad Fahmi Lim

2015-09-01

A novel powdering material that utilizes acid-modified Imperata cylindrica (IC) powder for the development of fingermarks was studied. Experiments were carried out to determine the suitability, adherence quality and sensitivity of the acid-modified IC powder. Fingermarks of different constituents (eccrine, sebaceous and natural fingermarks) on different types of surfaces were used. Acid-modified IC powder was also used to develop fingermarks of different ages as well as aged fingermarks recovered from the water. From the visual inspection, acid-modified IC powder was able to interact with different fingermark constituents and produced distinct ridge details on the examined surfaces. It was also able to develop aged fingermarks and fingermarks that were submerged in water. A statistical comparison was made against the Sirchie® Hi-Fi black powder in terms of the powders' sensitivity and quality of the developed natural fingermarks. The image quality was analyzed using MITRE's Image Quality of Fingerprint (IQF) software. From the experiments, acid-modified IC powder has the potential as a fingermark development powder, although natural fingermarks developed by Sirchie® black powder showed better quality and sensitivity based on the results of the statistical comparison. Copyright © 2015 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.

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...

Study of airborne particle generated by free falling powder

International Nuclear Information System (INIS)

Jacquelin, M.

2007-10-01

This study comes within the general framework of industrial facilities' safety research. Indeed, industrial processes, notably in the nuclear field, handle hazardous materials in powder form and can produce large quantities of fugitive dust. The study of the particles resuspension from powders is of interest of first order in order to estimate the consequences of this source term of contamination on the operator, the neighbouring installations and, if necessary, the environment. Up to now, there are very few reliable data in the scientific literature on the particulate emission in case of a scenario with an accidental free fall spill of powder. The powder dustiness evaluation is carried out using coefficients obtained in experiments, or using empirical correlations. The objective of the present work is to study the influence of some parameters involved in the airborne particles production by a free fall of powder. For that purpose, experiments are carried out in order to study the influence of parameters such as the type of discharge, the powder nature, the type of surface on which occurs the powder impaction, the system diameter used for discharge, and the falling mass. The results of mass fractions and number concentrations obtained highlighted the dominating parameters according to the type of discharge employed. Thereafter, the comparisons between our results and the empirical correlations available in the literature showed that those led to an undervaluation of the powder dustiness. This thus led us to develop, starting from the whole of experimental data, empirical correlations taking into account the various parameters studied as well as the interactions. (author)

Cellulose powder from Cladophora sp. algae.

Science.gov (United States)

Ek, R; Gustafsson, C; Nutt, A; Iversen, T; Nyström, C

1998-01-01

The surface are and crystallinity was measured on a cellulose powder made from Cladophora sp. algae. The algae cellulose powder was found to have a very high surface area (63.4 m2/g, N2 gas adsorption) and build up of cellulose with a high crystallinity (approximately 100%, solid state NMR). The high surface area was confirmed by calculations from atomic force microscope imaging of microfibrils from Cladophora sp. algae.

New automated pellet/powder assay system

International Nuclear Information System (INIS)

Olsen, R.N.

1975-01-01

This paper discusses an automated, high precision, pellet/ powder assay system. The system is an active assay system using a small isotopic neutron source and a coincidence detection system. The handling of the pellet powder samples has been automated and a programmable calculator has been integrated into the system to provide control and data analysis. The versatile system can assay uranium or plutonium in either active or passive modes

Powder bed charging during electron-beam additive manufacturing

International Nuclear Information System (INIS)

Cordero, Zachary C.; Meyer, Harry M.; Nandwana, Peeyush; Dehoff, Ryan R.

2017-01-01

Electrons injected into the build envelope during powder bed electron-beam additive manufacturing can accumulate on the irradiated particles and cause them to repel each other. Under certain conditions, these electrostatic forces can grow so large that they drive the particles out of the build envelope in a process known as “smoking”. In the present work, we investigate the causes of powder bed charging and smoking during electron-beam additive manufacturing. In the first part of the paper, we characterize the surface chemistry of a common feedstock material—gas-atomized Ti-6Al-4V powder—and find that a thick, electrically insulating oxide overlayer encapsulates the particles. Based on these experimental results, we then formulate an analytical model of powder bed charging in which each particle is approximated as a capacitor, where the particle and its substrate are the electrodes and the oxide overlayer is the dielectric. Using this model, we estimate the charge distribution in the powder bed, the electrostatic forces acting on the particles, and the conditions under which the powder bed will smoke. It is found that the electrical resistivity of the oxide overlayer strongly influences the charging behavior of the powder bed and that a high resistivity promotes charge accumulation and consequent smoking. This analysis suggests new quality control and process design measures that can help suppress smoking.

Ceramic grade (U,Pu)O2 powder fabrication

International Nuclear Information System (INIS)

Cristallini, O.A.; Villegas de Maroto, Marina; De Pino, J.I.; Osuna, H.A.

1980-01-01

Ceramic grade UO 2 powder was obtained by the homogeneous precipitation method. This procedure was afterwards applied to the fabrication of ceramic grade (U,Pu)O 2 powders, and mixed oxide powders with Pu content ranging from 0.7 to 16% were obtained. The obtainment of mixed ceramic oxides as well as the recuperation of fabrication scraps were developed in three steps: 1)study of the process of homogeneous precipitation of ammonium diuranate (ADU); 2) co-precipitation of ADU/PuO 2 .H 2 O for Pu concentrations of 0.6 and 6.8; 3) the thermal conditioning to mixed oxide (U,Pu)O 2 powders. The experimental procedure involves the following steps: preparation of the PuO 2 (NO 3 ) 4 solution; co-precipitation of the PuO 2 (NO 3 ) 2 solution with an UO 2 (NO 3 ) 2 solution; filtration and drying of the precipitate, thermal treatment and finally, mixing, pressing and sintering of the (U,Pu)O 2 and Nukem UO 2 powder with a 0. of zinc stearate. Different controls were made by means of physical, chemical and ceramographic tests. This method can be used for the fabrication of fast reactor fuels or, previous mechanical dispersion in UO 2 powder, for the fabrication of thermal reactors fuels. (M.E.L.) [es

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.

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

Directory of Open Access Journals (Sweden)

Dmitri GOLJANDIN

2012-03-01

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

Particle-particle interactions in aluminum reduction of boron oxide

International Nuclear Information System (INIS)

Logan, K.V.; McLemore, W.J.S.; Sparrow, J.T.

1988-01-01

The Georgia Tech Research Institute has been studying the use of thermite reactions for the production of specialized compounds since the mid-1950's. One of the goals of the research at GTRI is to define the reaction mechanism in order to be ble to predict the resultant reaction behaviour and thus prevent hazardous conditions. Thermite processing advantages are discussed in this paper. A typical thermite type of reaction to produce a composite titanium diboride/alumina is shown. The reactions typically use three starting materials for the production of a specific compound. A preliminary experimental mechanistic model of the extremely exothermic oxidation-reduction reaction is being developed

Zirconia powders production by precipitation: state-of-art review

International Nuclear Information System (INIS)

Oliveira, Ana Paula Almeida de; Torem, Mauricio Leonardo

1994-01-01

The important role played by zirconia in advanced ceramics can be attributed to its excellent wear and corrosion resistance and refractory character. The polymorphic nature of zirconia made the controlled addition of stabilizing oxides or the constraining effect of a dense ceramics matrix necessary to maintain high parameters had a significant influence on powder properties and on compacted powder behaviour in sintering. Particle shape and size, purity and crystalline structure were specially influenced by precipitation parameters. Therefore, this work presented a review of the state of the art in zirconia powder production and in the recent research on precipitation of that powder. (author)

Characterization of Cobalt F-75 powder for biomedical application

International Nuclear Information System (INIS)

Zuraidawani, C.D.; Shamsul, J.B.; Fazlul, B.; Nur Hidayah, A.Z.

2007-01-01

Cobalt F-75 alloys is commonly used for surgical implants because of their strength, corrosion resistance, non-magnetic behaviour and biocompatibility. In this paper, gas atomized of Cobalt F-75 powders were selected for evaluation. These powders supplied by Sandvik Osprey Ltd. The characteristics of these powders were investigated by using particle size analysis, X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and Scanning Electron Microscope (SEM). Two different powder sizes (8.8 μm and 11.5 μm) have showed spherical morphology and the value of densities are 7.9 and 7.6 g/cm 3 respectively. (author)

Fine crystalline powders. Analysis of scientific and technical literature

International Nuclear Information System (INIS)

Denisenko, Eh.T.; Kulik, O.P.; Eremina, T.V.

1983-01-01

The state of development and studies of fine crystalline powders for recent five years is reviewed in the paper. Based on data available in literature, the most significant methods for fine metal and alloy powder production are considered and physicochemical properties of ultrafine particles are discussed from the standpoint of their interrelation with promising techniques for powder production. It is stated that the most important feature of ultrafine powder production technique at the present stage is a transition from the stage of data accumulation to that of controlled production of ultrafine structures of various metals and alloys under controllable conditions

Powder densification maps in Selective Laser Sintering

International Nuclear Information System (INIS)

Bourell, D.; Wohlert, M.; Harlan, N.; Beaman, J.; Das, S.

2002-01-01

Selective Laser Sintering (SLS) is a manufacturing process in which a part is produced without the need for part-specific tooling. It competes effectively with other manufacturing processes when part geometry is complex and the production run is not large. Traditionally, this was limited to prototype production, although tooling applications are now appearing. This paper describes several applications of powder densification maps to advance solutions in direct SLS of metallic and ceramic powders. Time-dependent plasticity issues arise in pre-processing of powder to make it suitable for SLS and in post-processing of SLS parts to obtain desired density. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

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.

Gas-Phase Combustion Synthesis of Aluminum Nitride Powder

Science.gov (United States)

Axelbaum, R. L.; Lottes, C. R.; Huertas, J. I.; Rosen, L. J.

1996-01-01

Due to its combined properties of high electrical resistivity and high thermal conductivity aluminum nitride (AlN) is a highly desirable material for electronics applications. Methods are being sought for synthesis of unagglomerated, nanometer-sized powders of this material, prepared in such a way that they can be consolidated into solid compacts having minimal oxygen content. A procedure for synthesizing these powders through gas-phase combustion is described. This novel approach involves reacting AlCl3, NH3, and Na vapors. Equilibrium thermodynamic calculations show that 100% yields can be obtained for these reactants with the products being AlN, NaCl, and H2. The NaCl by-product is used to coat the AlN particles in situ. The coating allows for control of AlN agglomeration and protects the powders from hydrolysis during post-flame handling. On the basis of thermodynamic and kinetic considerations, two different approaches were employed to produce the powder, in co-flow diffusion flame configurations. In the first approach, the three reactants were supplied in separate streams. In the second, the AlCl3 and NH3 were premixed with HCl and then reacted with Na vapor. X-ray diffraction (XRD) spectra of as-produced powders show only NaCl for the first case and NaCl and AlN for the second. After annealing at 775 C tinder dynamic vacuum, the salt was removed and XRD spectra of powders from both approaches show only AlN. Aluminum metal was also produced in the co-flow flame by reacting AlCl3 with Na. XRD spectra of as-produced powders show the products to be only NaCl and elemental aluminum.

RESEARCH REGARDING THE CHEMICAL COMPOSITION OF POWDER MILK WITH NUTRIENTS

Directory of Open Access Journals (Sweden)

Liviu Giurgiulescu

2009-06-01

Full Text Available Powdered milk is a manufactured dairy product made by evaporating milk to dryness. This product has incomposition powder apple, powder carrots, rice flour and corn flour, vitamins, minerals.One purpose of drying milk is to preserve it; milk powder has a far longer self life than liquid milk and does notneed to be refrigerated, due to its low moisture content. Another purpose is to reduce its bulk for economy oftransportation. Milk powders contain all twenty standards amino acids and are high insoluble vitamins and minerals.The typical average amounts of major nutrients in the un reconstituted in 100 g milk are (by weight 12,7g protein,68,2g carbohydrates (predominantly lactose, calcium 427g , potassium g, vitamins11g, Inappropriate storageconditions (high relative humidity and high ambient temperature can significantly degrade the nutritive value ofmilk powder.

Synthesis of alumina powders by precipitation method and solvothermal treatment

International Nuclear Information System (INIS)

Politchuk, J.O.; Lima, N.B.; Lazar, D.R.R.; Ussui, V.; Yoshito, W.K.

2012-01-01

The improvement of alumina powders synthesis processes has been focused on the preparation of ceramic powders with well defined crystalline structure and with high specific surface area and nanometric particle size without formation of hard agglomerates. For this purpose the precipitation step should be studied and and also the temperature of alumina crystallization should be reduced. The aim of this study was to obtain alumina powders by hydroxide precipitation with ammonia in the presence of cationic surfactant, followed by solvothermal treatment and calcination. The powders were characterized by TG/DTA, X-ray diffraction, surface area measurements by gas adsorption (BET) and scanning electron microscopy. The results showed that powders produced by solvothermal treatment without surfactant have higher crystallinity. However the presence of CTAB enhances 240% the specific surface area compared with powders produced without this reagent (author)

Process for titanium powders spheroidization by RF induction plasma

International Nuclear Information System (INIS)

Gu Zhongtao; Ye Gaoying; Liu Chuandong; Tong Honghui

2010-01-01

Spherical titanium (Ti) particles were obtained by the process of heating irregularly shaped Ti powders under the radio frequency induction plasma (RF induction plasma) condition. The effect of feed rate, various dispersion methods and Ti particle size on the spheroidization efficiency was studied. The efficiency of the spheroidization is evaluated through the measurements of the percentage of powder spheroidized based on the electron microscopic observations and the tap density measurement of the processed powder. During the short flight of the particles in the plasma flow, of the order of a few milliseconds, the individual titanium particles of the powder are heated and melt, forming a spherical liquid droplet which upon freezing gives rise to the formation of a perfectly dense spherical solid particle. So RF induction plasma is a promising method for the preparation of spherical titanium powders with high flow ability. (authors)

Physcio chemical analysis of browning inhibitors treated solanum turberosum powder

International Nuclear Information System (INIS)

Alizai, M.N.K.; Abid, H.

2008-01-01

White potatoes (Solanum turberosum) were procured from agriculture Research Institute Tarnab Farm Peshawar to use for the preparation of potato powder. The process involves sorting. Washing, peeling slicing, blanching, treating with poly phenol oxidase inhibitors, dehydration, grinding and packing. All these parameters used in process were standardized. Chemical analysis of fresh potato and potato powder were carried out. Microbiological examination, functional properties and storage life studies of the potato powder were also performed. The product prepared by drying in cabinet dryer at 55 C for 7 hours was off white colour potatoes chips which was grinded to make off white potato powder. The potato powder possessed taste and texture. (author)

The tungsten powder study of the dispenser cathode

International Nuclear Information System (INIS)

Bao Jixiu; Wan Baofei

2006-01-01

The intercorrelation of tungsten powder properties, such as grain size, distribution and morphology, and porous matrix parameters with electron emission capability and longevity of Ba dispenser cathodes has been investigated for the different grain morphologies. It is shown that a fully cleaning step of the tungsten powder is so necessary that the tungsten powder will be reduction of oxide in hydrogen atmosphere above 700 deg. C. The porosity of the tungsten matrix distributes more even and the closed pore is fewer, the average granule size of the tungsten powder distributes more convergent. The porosity of the tungsten matrix and the evaporation of the activator are bigger and the pulse of the cathode is smaller when the granularity is bigger by the analysis of the electronic microscope and diode experiment

The tungsten powder study of the dispenser cathode

Science.gov (United States)

Bao, Ji-xiu; Wan, Bao-fei

2006-06-01

The intercorrelation of tungsten powder properties, such as grain size, distribution and morphology, and porous matrix parameters with electron emission capability and longevity of Ba dispenser cathodes has been investigated for the different grain morphologies. It is shown that a fully cleaning step of the tungsten powder is so necessary that the tungsten powder will be reduction of oxide in hydrogen atmosphere above 700 °C. The porosity of the tungsten matrix distributes more even and the closed pore is fewer, the average granule size of the tungsten powder distributes more convergent. The porosity of the tungsten matrix and the evaporation of the activator are bigger and the pulse of the cathode is smaller when the granularity is bigger by the analysis of the electronic microscope and diode experiment.

Comparative toxicity of four local botanical powders to Sitophilus ...

African Journals Online (AJOL)

Maize grains were admixed with the powders at the rates0, 5, 10, 20 and 40 g/kg for the assessment of mortality over a 14-d or 30-d period, as well as for population increase and damage. Within 14-d exposure, P. glandulosus powder caused the highest weevil mortality followed by A. indica. A. indica powder was by far ...

Synthesis and characterization of nanoboron powders prepared with ...

Indian Academy of Sciences (India)

mechanochemical reaction between B2O3 and Mg powders ... Malek—Ashtar University of Technology, School of Chemistry and Chemical Engineering, Tehran, P.O. Box .... powders and chemical reaction takes place at the interface of.

Modeling of microwave heating of metallic powders

International Nuclear Information System (INIS)

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

2008-01-01

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

Double Step Sintering Behavior Of 316L Nanoparticle Dispersed Micro-Sphere Powder

Directory of Open Access Journals (Sweden)

Jeon Byoungjun

2015-06-01

Full Text Available 316L stainless steel is a well-established engineering material and lots of components are fabricated by either ingot metallurgy or powder metallurgy. From the viewpoints of material properties and process versatility, powder metallurgy has been widely applied in industries. Generally, stainless steel powders are prepared by atomization processes and powder characteristics, compaction ability, and sinterability are quite different according to the powder preparation process. In the present study, a nanoparticle dispersed micro-sphere powder is synthesized by pulse wire explosion of 316L stainless steel wire in order to facilitate compaction ability and sintering ability. Nanoparticles which are deposited on the surface of micro-powder are advantageous for a rigid die compaction while spherical micro-powder is not to be compacted. Additionally, double step sintering behavior is observed for the powder in the dilatometry of cylindrical compact body. Earlier shrinkage peak comes from the sintering of nanoparticle and later one results from the micro-powder sintering. Microstructure as well as phase composition of the sintered body is investigated.

Physical and Sensory Properties of Ice Cream Containing Fermented Pepper Powder.

Science.gov (United States)

Yeon, Su-Jung; Kim, Ji-Han; Hong, Go-Eun; Park, Woojoon; Kim, Soo-Ki; Seo, Han-Geuk; Lee, Chi-Ho

2017-01-01

This study was conducted to investigate the physical and sensory properties of ice cream containing fermented pepper powder. Three ice cream formulas were manufactured: 1, control; 2, supplemented with 0.1% fermented pepper powder; and 3, supplemented with 0.2% fermented pepper powder. Formulas 2 and 3 had significantly higher viscosity and lower overrun than formula 1 ( p ice creams supplemented with fermented pepper powder were harder and maintained their forms longer than the controls. 0.2% fermented pepper powder added ice cream had no pungency as much as that of control and overall sensory attribute was not significantly different from control. Therefore, ice cream containing fermented pepper powder maintained physical and sensory properties similar to the controls, and maintenance was better. It means fermented pepper powder ice cream can be utilized as the material of functional food (dessert).

Sol-gel synthesis and densification of aluminoborosilicate powders. Part 1: Synthesis

Science.gov (United States)

Bull, Jeffrey; Selvaduray, Guna; Leiser, Daniel

1992-01-01

Aluminoborosilicate powders high in alumina content were synthesized by the sol-gel process utilizing various methods of preparation. Properties and microstructural effects related to these syntheses were examined. After heating to 600 C for 2 h in flowing air, the powders were amorphous with the metal oxides comprising 87 percent of the weight and uncombusted organics the remainder. DTA of dried powders revealed a T(sub g) at approximately 835 C and an exotherm near 900 C due to crystallization. Powders derived from aluminum secbutoxide consisted of particles with a mean diameter 5 microns less than those from aluminum isopropoxide. Powders synthesized with aluminum isopropoxide produced agglomerates comprised of rod shaped particulates while powders made with the secbutoxide precursor produced irregular glassy shards. Compacts formed from these powders required different loadings for equivalent densities according to the method of synthesis.

Safety assessment of Superba™ krill powder: Subchronic toxicity study in rats

Directory of Open Access Journals (Sweden)

Kjetil Berge

2015-01-01

Full Text Available The safety of krill powder was assessed in a subchronic 13-week toxicity study where rats were fed krill powder or control diets. The krill powder inclusion in the test diet was 9.67% (w/w. There were no differences noted in body weight or food consumption in either gender. Differences in clinical chemistry values were noted in the krill powder-treated animals, but these findings were of no toxicological significance. A significant decrease in absolute heart weight, but not relative heart weight, was observed in both sexes given krill powder, although no corresponding histological changes were observed. Hepatocyte vacuolation was noted histologically in males fed krill powder. This finding was not associated with other indications of hepatic dysfunction. The no observed adverse effect level (NOAEL for the conditions of this study was considered to be 9.67% krill powder.

Acid-base properties of ceramic powders

International Nuclear Information System (INIS)

Bleier, A.

1983-01-01

This chapter addresses the fundamental aspects of potentiometric titration, electrokinetics, and conductometric titration in evaluating surface and interfacial thermodynamic behavior. Emphasizes the characterization of aqueous systems which are pertinent to the processing of ceramic powders. Attempts to clarify the role of novel analytical techniques that will increasingly contribute to the advanced characterization of ceramic powders. Evaluates recently developed acid-base and complexation concepts and their applications to the processing of oxide ceramics

Powder preparation and compaction behaviour of fine-grained Y-TZP

NARCIS (Netherlands)

Groot Zevert, W.F.M.; Winnubst, Aloysius J.A.; Theunissen, G.S.A.M.; Burggraaf, A.J.

1990-01-01

Two wet chemical preparation methods are described for yttria-doped tetragonal zirconia powders. Both methods yield powders with an extremely small crystallite size (8 nm) and a narrow size distribution. The agglomerate and aggregate structure of these powders have been investigated by several

Melting of Uranium Metal Powders with Residual Salts

International Nuclear Information System (INIS)

Jin-Mok Hur; Dae-Seung Kang; Chung-Seok Seo

2007-01-01

The Advanced Spent Fuel Conditioning Process (ACP) of the Korea Atomic Energy Research Institute focuses on the conditioning of Pressurized Water Reactor spent oxide nuclear fuel. After the oxide reduction step of the ACP, the resultant metal powders containing ∼ 30 wt% residual LiCl-Li 2 O should be melted for a consolidation of the fine metal powders. In this study, we investigated the melting behaviors of uranium metal powders considering the effects of a LiCl-Li 2 O residual salt. (authors)

Microstructure of rapidly solidified Nb-based pre-alloyed powders for additive manufacturing

Energy Technology Data Exchange (ETDEWEB)

Guo, Yueling; Jia, Lina, E-mail: jialina@buaa.edu.cn; Kong, Bin; Zhang, Shengnan; Zhang, Fengxiang; Zhang, Hu

2017-07-01

Highlights: • Sphere shaped Nb-37Ti-13Cr-2Al-1Si pre-alloyed powders were prepared by PREP. • An oxide layer with a thickness of 9.39 nm was generated on the powder surface. • The main phases of the pre-alloyed powders were Nbss and Cr{sub 2}Nb. • SDAS increased and microhardness decreased with the increase of powder size. • Microstructure of powders evolved into large grains from dendrite structures after HT. - Abstract: For powder-based additive manufacturing, sphere-shaped Nb-37Ti-13Cr-2Al-1Si pre-alloyed powders were prepared by plasma rotating electrode processing (PREP). The microstructure, surface oxidation and microhardness of the pre-alloyed powders were systematically investigated. Results showed that the main phases were Nb solid solution (Nbss) and Cr{sub 2}Nb. The Cr{sub 2}Nb phases were further determined using transmission electron microscopy (TEM). Fine dendrite structures were observed in the as-fabricated pre-alloyed powders, which transformed to large grains after heat treatment (HT) at 1450 °C for 3 h. With the increase of powder size, the secondary dendrite arm spacing (SDAS) increased and the microhardness (HV) decreased. A clean powder surface free of oxide particles was obtained by PREP and an oxide layer with 9.39 nm in thickness was generated on the powder surface. Compared with Cr- and Nb-oxides, more Ti-oxides were formed on outmost powder surface with a higher content of Ti (up to 47.86 at.%). The differences upon the microstructure and microhardness of the pre-alloyed powders with different sizes were discussed.

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.

Powder Flux Regulation in the Laser Material Deposition Process

Science.gov (United States)

Arrizubieta, Jon Iñaki; Wegener, Maximiliam; Arntz, Kristian; Lamikiz, Aitzol; Ruiz, Jose Exequiel

In the present research work a powder flux regulation system has been designed, developed and validated with the aim of improving the Laser Material Deposition (LMD) process. In this process, the amount of deposited material per substrate surface unit area depends on the real feed rate of the nozzle. Therefore, a regulation system based on a solenoid valve has been installed at the nozzle entrance in order to control the powder flux. The powder flux control has been performed based on the machine real feed rate, which is compared with the programmed feed rate. An instantaneous velocity error is calculated and the powder flow is controlled as a function of this variation using Pulse Width Modulation (PWM) signals. Thereby, in zones where the Laser Material Deposition machine reduces the feed rate due to a trajectory change, powder accumulation can be avoided and the generated clads would present a homogeneous shape.

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.

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.

Synthesis and densification of Cu-coated Ni-based amorphous composite powders

International Nuclear Information System (INIS)

Kim, Yong-Jin; Kim, Byoung-Kee; Kim, Jin-Chun

2007-01-01

Spherical Ni 57 Zr 20 Ti 16 Si 2 Sn 3 (numbers indicate at.%) amorphous powders were produced by the gas atomization process, and ductile Cu phase was coated on the Ni-based amorphous powders by the spray drying process in order to increase the ductility of the consolidated amorphous alloy. The characteristics of the as-prepared powders and the consolidation behaviors of Cu-coated Ni-based amorphous composite powders were investigated. The atomization was conducted at 1450 deg. C under the vacuum of 10 -2 mbar. The Ni-based amorphous powders and Cu nitrate solution were mixed and sprayed at temperature of 130 deg. C. After spray drying and reduction treatment, the sub-micron size Cu powders were coated successfully on the surface of the atomized Ni amorphous powders. The spark plasma sintering process was applied to study the densification behavior of the Cu-coated composite powders. Thickness of the Cu layer was less than 1 μm. The compacts obtained by SPS showed high relative density of over 98% and its hardness was over 800 Hv

Numerical algorithm for laser treatment of powder layer with variable thickness

Science.gov (United States)

Soboleva, Polina; Knyazeva, Anna

2017-12-01

Two-dimensional model of laser treatment of powder layer on the substrate is proposed in this paper. The model takes into account the shrinkage of powder layer due to the laser treatment. Three simplified variants of the model were studied. Firstly, the influence of optical properties of powder layer on the maximal temperature was researched. Secondly, two-dimensional model for given thickness of powder layer was studied where practically uniform temperature distribution across thin powder layer was demonstrated. Then, the numerical algorithm was developed to calculate the temperature field for the area of variable size. The impact of the optical properties of powder material on the character of the temperature distribution was researched numerically.

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.

Effect of Powder-Suspended Dielectric on the EDM Characteristics of Inconel 625

Science.gov (United States)

Talla, Gangadharudu; Gangopadhyay, S.; Biswas, C. K.

2016-02-01

The current work attempts to establish the criteria for powder material selection by investigating the influence of various powder-suspended dielectrics and machining parameters on various EDM characteristics of Inconel 625 (a nickel-based super alloy) which is nowadays regularly used in aerospace, chemical, and marine industries. The powders include aluminum (Al), graphite, and silicon (Si) that have significant variation in their thermo-physical characteristics. Results showed that powder properties like electrical conductivity, thermal conductivity, density, and hardness play a significant role in changing the machining performance and the quality of the machined surface. Among the three powders, highest material removal rate was observed for graphite powder due to its high electrical and thermal conductivities. Best surface finish and least radial overcut (ROC) were attained using Si powder. Maximum microhardness was found for Si due to its low thermal conductivity and high hardness. It is followed by graphite and aluminum powders. Addition of powder to the dielectric has increased the crater diameter due to expansion of plasma channel. Powder-mixed EDM (PMEDM) was also effective in lowering the density of surface cracks with least number of cracks obtained with graphite powder. X-ray diffraction analysis indicated possible formation of metal carbides along with grain growth phenomenon of Inconel 625 after PMEDM.

Development of equipment for fabricating DUPIC fuel powder

International Nuclear Information System (INIS)

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

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.

Ductile zirconium powder by hydride-dehydride process

Energy Technology Data Exchange (ETDEWEB)

Krishnan, T S [BHABHA ATOMIC RESEARCH CENTRE, BOMBAY (INDIA); CHAUDHARY, S [NUCLEAR FUEL COMPLEX, HYDERABAD (INDIA)

1976-09-01

The preparation of ductile zirconium powder by the hydride-dehydride process has been described. In this process massive zirconium obtained from Kroll reduction of ZrCl/sub 4/ is first rendered brittle by hydrogenation and the hydride crushed and ground in a ball mill to the required particle size. Hydrogen is then hot vacuum extracted to yield the metal powder. The process has been successfully employed for the production of zirconium powders with low oxygen content and having hardness values in the range of 115-130 BHN, starting from a zirconium sponge of 100-120 BHN hardness. Influence of surface characteristics of the starting metal on its hydriding behaviour has been studied and the optimum hydriding-dehydriding conditions established.

Tungsten and tungsten alloys by powder metallurgy

International Nuclear Information System (INIS)

Belhadjhamida, A.; German, R.M.

1991-01-01

Tungsten has a historical link with powder metallurgy and there is continued progress in expanding the available compositions and processing options. This paper starts with an introduction to the history of tungsten powder metallurgy and use this as a basis for analyzing some of the current trends. The literature base in tungsten processing is expanding and includes new alloys, microstructures, and processing routes. A few examples will be emphasize here to produce a frame work for this program, including description of sintering mechanisms for tungsten, liquid phase sintering advances, hot consolidation fundamentals, and options for complex shaping using powder injection modeling. For this base, subsequent presentations will expand on these fundamental advances

Near-Net Shape Powder Metallurgy Rhenium Thruster

Science.gov (United States)

Leonhardt, Todd; Hamister, Mark; Carlen, Jan C.; Biaglow, James; Reed, Brian

2001-01-01

This paper describes the development of a method to produce a near-net shape (NNS) powder metallurgy (PM) rhenium combustion chamber of the size 445 N (100 lbf) used in a high performance liquid apogee engine. These engines are used in low earth Orbit and geostationary orbit for satellite positioning systems. The developments in near-net shape powder metallurgy rhenium combustion chambers reported in this paper will reduce manufacturing cost of the rhenium chambers by 25 percent, and reduce the manufacturing time by 30 to 40 percent. The quantity of rhenium metal powder used to produce a rhenium chamber is reduced by approximately 70 percent and the subsequent reduction in machining schedule and costs is nearly 50 percent.

PREPARATION OF WC-Co POWDER BY DIRECT REDUCTION AND CARBONIZATION

Institute of Scientific and Technical Information of China (English)

Zhonglai Yi; Gangqin Shao; Xinglong Duan; Peng Sun; Xiaoliang Shi; Zhen Xiong; Jingkun Guo

2005-01-01

A new approach to produce superfine WC-Co powder by direct reduction and carbonization is proposed.Water-soluble salts containing W and Co were used as raw materials. Tungsten and cobalt oxide powder (CoWO4/WO3)was first formed by a spray-pyrolysis technique, which was then mixed with carbon black and converted to WC-Co composite powder at 950℃ for 4 h in N2 atmosphere. The resulting powder has a particle size of 100-300 nm.

Porous Nb-Ti based alloy produced from plasma spheroidized powder

OpenAIRE

Li, Qijun; Zhang, Lin; Wei, Dongbin; Ren, Shubin; Qu, Xuanhui

2017-01-01

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 decr...

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.

Superconducting properties of in situ powder-in-tube-processed MgB2 tapes fabricated with sub-micrometre Mg powder prepared by an arc-plasma method

International Nuclear Information System (INIS)

Yamada, H; Uchiyama, N; Matsumoto, A; Kitaguchi, H; Kumakura, H

2007-01-01

We fabricated in situ powder-in-tube-processed MgB 2 /Fe tapes using sub-micrometre Mg powder prepared by applying an arc-plasma method. We found that the use of this sub-micrometre Mg powder was very effective in increasing the J c values. The transport J c value of 10 mol% SiC-added tapes fabricated with this sub-micrometre Mg powder reached 275 A mm -2 at 4.2 K and 10 T. This value was about six times that of 5 mol% SiC-added tapes fabricated with commercial Mg powder. Microstructure analyses suggest that this J c enhancement is primarily due to the smaller MgB 2 grain size

γ-ray radiation decontamination of barley plant powder

International Nuclear Information System (INIS)

Zhao Xiaojun; Fu Junjie; Wang Zhiping; Zhang Guobin

2007-01-01

Radiation decontamination of barley plant powder by 60 Co γ-rays and the effect on its components were studied. Results showed that irradiation was very effective in killing the microorganisms in barley plant powder. The irradiation did not cause obvious changes of the major components of protein, total sugar, free amino acid, crude fiber, but 35% loss of vitamin E was observed after 10kGy irradiation. It is suggested that 7.5-10kGy irradiation is good enough for decontamination of the barley plant powder. (authors)

Barium strontium titanate powders prepared by spray pyrolysis

International Nuclear Information System (INIS)

Brankovic, G.; Brankovic, Z.; Goes, M.S.; Paiva-Santos, C.O.; Cilense, M.; Varela, J.A.; Longo, E.

2005-01-01

Ultasonic spray pyrolysis (SP) has been investigated for the production of the barium strontium titanate (BST) powders from the polymeric precursors. The processing parameters, such as flux of aerosol and temperature profile inside the furnace, were optimized to obtain single phase BST. The powders were characterized by the methods of X-ray diffraction analysis, SEM, EDS and TEM. The obtained powders were submicronic, consisting of spherical, polycrystalline particles, with internal nanocrystalline structure. Crystallite size of 10 nm, calculated using Rietveld refinement, is in a good agreement with results of HRTEM

Deformed liquid marbles: Freezing drop oscillations with powders

KAUST Repository

Marston, Jeremy; Zhu, Y.; Vakarelski, Ivan Uriev; Thoroddsen, Sigurdur T

2012-01-01

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.

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.

21 CFR 520.905d - Fenbendazole powder.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Fenbendazole powder. 520.905d Section 520.905d... DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.905d Fenbendazole powder. (a) Specifications. (1) Each 2-ounce packet contains 2.27 grams (4 percent) of fenbendazole plus other inert...

New manufacturing method for Fe-Si magnetic powders using modified pack-cementation process

Science.gov (United States)

Byun, Ji Young; Kim, Jang Won; Han, Jeong Whan; Jang, Pyungwoo

2013-03-01

This paper describes a new method for making Fe-Si magnetic powders using a pack-cementation process. It was found that Fe-Si alloy powders were formed by a reaction of the pack mixture of Fe, Si, NaF, and Al2O3 powders at 900 °C for 24 h under a hydrogen atmosphere. Separation of the Fe-Si alloy powders was dependent on the particle size of the Fe powders in the pack. For small Fe powders, magnetic separation in a medium of strong alkali solution was recommended. But, for relatively larger Fe powders, the Fe-Si alloy powders were easily separated from Al2O3 powders using a magnet in air atmosphere. The Si content in the Fe-Si magnetic powders were easily controlled by changing the weight ratio of Si to (Si+Fe) in the pack.

Plasma deposition by discharge in powder

International Nuclear Information System (INIS)

El-Gamal, H.A.; El-Tayeb, H.A.; Abd El-Moniem, M.; Masoud, M.M.

2000-01-01

Different types of material powders have been fed to the breach of a coaxial discharge. The coaxial discharge is powered from a 46.26 mu F, 24 KV capacitor bank. When the discharge takes place at the breach, the powder is heated and ionized to form a sheath of its material. The plasma sheath is ejected from the discharge zone with high velocity. The plasma sheath material is deposited on a glass substrate. It has been found from scanning electron microscope (SEM) analysis that the deposited material is almost homogenous for ceramic and graphite powders. The grain size is estimated to be the order of few microns. To measure the deposited material thickness the microdensitometer and a suitable arrangement of a laser interferometer and an optical microscope are used. It has also been found that deposited material thickness depends on the discharge number of shots and the capacitor bank energy

Development and applications of ultrafine aluminium powders

International Nuclear Information System (INIS)

Kearns, Martin

2004-01-01

Over the last 20 years or so, a variety of new technologies has been developed to produce sub-micron powders. Among the products attracting interest is nanoaluminium which is being evaluated in specialist propulsion and exothermic end-uses. This paper examines the advances made in 'nanopowder' production in the context of the existing aluminium powder industry where finest commercial grades have a median size of ∼6 μm (one or two orders of magnitude coarser than nanopowders) and which today supplies the markets being targeted by nanopowders with coarser, but effective products. Are there genuine market opportunities for nanoaluminium and if so, how will they be produced? One the one hand there are the novel nanopowder production methods which are high yielding but generally slow and costly, while on the other, there is the very fine fraction from conventional atomising routes which generate a very low yield of sub-micron powder but which nevertheless can translate into a meaningful rate as part of the bulk production. Can conventional routes ever hope to make sufficient volumes of nanopowders cost effectively and which will be the favoured routes in future? Moreover, what of the 'ultrafine' size range (∼0.5-5 μm) which is of more immediate potential interest to today's powder users. This paper seeks to identify the near term opportunities for application of low volume/high value ultrafine and nano powders

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.

Structural comparison of sintering products made of "TiC + Ti" composite powders and "Ti + C" powder mixtures

Science.gov (United States)

Krinitcyn, Maksim G.; Pribytkov, Gennadii A.; Korosteleva, Elena N.; Firsina, Irina A.; Baranovskii, Anton V.

2017-12-01

In this study, powder composite materials comprised of TiC and Ti with different ratios are processed by sintering of Ti and C powder mixtures and self-propagating high-temperature synthesis (SHS) in "Ti+C" system followed by sintering. The microstructure and porosity of obtained composites are investigated and discussed. The dependence of porosity on sintering time is explained theoretically. Optimal regimes that enable to obtain the most homogeneous structure with the least porosity are described.

Effect of carbon on mechanical properties of powder-processed Fe ...

Indian Academy of Sciences (India)

The present paper records the results of mechanical tests on iron-phosphorus powder alloys which were made using a hot powder forging technique. In this process mild steel encapsulated powders were hot forged into slabs, hot rolled and annealed to relieve the residual stresses. These alloys were characterized in terms ...

Investigation of Magnetic Pulse Deformation of Powder Parts

OpenAIRE

Kolbe, M.; Mironov, V.; Shishkin, A.; Zemchenkov, V.

2012-01-01

Current article covers basics of powder compaction by electromagnetic impulse field and research results of sintered Fe powder part deformation process. This work is a joint research carried out by Riga Technical University (Latvia) and the Westsächsische Hochschule Zwickau (Germany).

Preparation and microwave shielding property of silver-coated carbonyl iron powder

International Nuclear Information System (INIS)

Cao, Xiao Guo; Ren, Hao; Zhang, Hai Yan

2015-01-01

Highlights: • The silver-coated carbonyl iron powder is prepared by the electroless plating process. • The silver-coated carbonyl iron powder is a new kind of conductive filler. • The reflection and absorption dominate the shielding mechanism of the prepared powder. • Increasing the thickness of electroconductive adhesive will increase the SE. - Abstract: Electroless silver coating of carbonyl iron powder is demonstrated in the present investigation. The carbonyl iron powders are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the coating process. The relatively uniform and continuous silver coating is obtained under the given coating conditions. In this paper, the electromagnetic interference (EMI) shielding mechanism of the silver-coated carbonyl iron powder is suggested. The reflection of silver coating and absorption of carbonyl iron powder dominate the shielding mechanism of the silver-coated carbonyl iron powder. The silver-coated carbonyl iron powders are used as conductive filler in electroconductive adhesive for electromagnetic interference shielding applications. The effect of the thickness of electroconductive adhesive on the shielding effectiveness (SE) is investigated. The results indicate that the SE increases obviously with the increase of the thickness of electroconductive adhesive. The SE of the electroconductive adhesive with 0.35 mm thickness is above 38 dB across the tested frequency range

Nano-scale analysis of titanium dioxide fingerprint-development powders

International Nuclear Information System (INIS)

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

2008-01-01

Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO 2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO 2 particles and efficacy of print development.

On the die compaction of powders used in pharmaceutics.

Science.gov (United States)

Aryanpour, Gholamreza; Farzaneh, Masoud

2018-07-01

Die compaction is widely used in the compaction of pharmaceutical powders (tableting). It is well known that the powder densification is a result of particle rearrangement and particle deformation. The former is considered to be the governing mechanism of densification in an initial stage of compaction and the latter is regarded as the governing mechanism in the compaction at the higher pressure range. As a more realistic assumption, one can consider that a simultaneous performance of both the rearrangement and deformation mechanisms takes place from the beginning of compaction. To mathematically formulate this assumption, a piston equation is presented where the material relative density is given as a function of the applied pressure on the powder. From the equation, it is possible to obtain the contribution of each mechanism to the material densification at each value of the applied pressure. In the continuation, the piston equation is applied to the tabletting of some pharmaceutical powders. These are the powders of Ascorbic Acid, Avicel ® PH 101, Avicel ® PH 301, Emcompress ® , Sodium Chloride, and Tablettose ® whose tableting results have been previously published in the literature. The results show the piston equation as a suitable approach to describe the tabletting of pharmaceutical powders.

Nano-scale analysis of titanium dioxide fingerprint-development powders

Energy Technology Data Exchange (ETDEWEB)

Reynolds, A J; Jones, B J [Experimental Techniques Centre, Brunei University, Kingston Lane, Uxbridge, Middlesex, UB8 3PH (United Kingdom); Sears, V; Bowman, V [Fingerprint and Footwear Forensics, Home Office Scientific Development Branch, Sandridge, St Albans, Hertfordshire, AL4 9HQ (United Kingdom)], E-mail: b.j.jones@physics.org

2008-08-15

Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO{sub 2} particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO{sub 2} particles and efficacy of print development.

Plasma spheroidization and cladding of powders

Energy Technology Data Exchange (ETDEWEB)

Petrunichev, V.A.; Averin, V.V.; Sorokin, L.M.; Koroleva, E.B.

1987-02-01

With reference to experimental results for nickel and chromium alloys, it is shown that complex alloy powders can be spheroidized in plasma discharges using an argon plasma with hydrogen. The spheroidizing process is accompanied by the reduction of surface oxides, with uniform element distribution within the particles; the granulometric composition of the particles is preserved. It is also shown that plasma technology can be used for producing metal-clad oxide and carbide powders, which improve the performance of cermets and coatings.

The refractive-index correction in powder diffraction

International Nuclear Information System (INIS)

Hart, M.; Parrish, W.; Bellotto, M.; Lim, G.S.

1988-01-01

Throughout the history of powder diffraction practice there has been uncertainty about whether or not a refractive-index correction should be made to Bragg's law. High-precision Bragg-angle measurements have been performed with synchrotron radiation on SRM-640 silicon powders at glancing angles; it is found that little or no correction is necessary for the usual 2θ angle range. (orig.)

Synthesis of vanadium oxide powders by evaporative decomposition of solutions

International Nuclear Information System (INIS)

Lawton, S.A.; Theby, E.A.

1995-01-01

Powders of the vanadium oxides V 2 O 4 , V 6 O 13 , and V 2 O 5 were produced by thermal decomposition of aqueous solutions of vanadyl sulfate hydrate in atmospheres of N 2 , H 2 mixed with N 2 , or air. The composition of the oxide powder was determined by the reactor temperature and gas composition. Residual sulfur concentrations in powders produced by decomposition at 740 C were less than 1 at.%, and these powders consisted of hollow, roughly spherical aggregates of particles less than 1 microm in diameter

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.

Physicochemical and Antioxidant Activities of Spray-dried Pitaya Fruit Powder

Science.gov (United States)

Li, Guopeng; Liu, Yangyang; Lin, Lijing; Li, Jihua

2018-01-01

Pitaya commonly known as dragon fruit is very popular in China due to its intense color, constituent minerals, vitamins, and antioxidant properties. In the present study, physiochemical properties and antioxidant activities of fruit powder from two pitaya cultivars (namely red flesh and white flesh) and fruit peel were observed. Compared with the fruit powder of fruit flesh, the fruit powder made from fruit peel showed a higher antioxidant activity. The current study provides insights to produce spray-dried pitaya fruit powders that could potentially be used as functional food ingredients in various food fields.

High yttria ferritic ODS steels through powder forging

Energy Technology Data Exchange (ETDEWEB)

Kumar, Deepak [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Prakash, Ujjwal, E-mail: ujwalfmt@iitr.ac.in [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Dabhade, Vikram V. [Department of Metallurgical and Materials Engineering, I.I.T-Roorkee, Uttarakhand 247667 (India); Laha, K.; Sakthivel, T. [Mechanical Metallurgy Group, IGCAR, Kalpakkam, Tamilnadu 603102 (India)

2017-05-15

Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y{sub 2}O{sub 3} (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility. - Highlights: •ODS steels with yttria contents beyond the conventional limit of 0.5 wt% were fabricated by powder forging in a hydrogen atmosphere. •All the alloys exhibited significant ductility. •This may be attributed to improved inter-particle bonding due to reduction of surface oxides by hydrogen. •Strength in excess of 300 MPa was obtained at 973 K for 0.5%, 1% and 1.5% yttria ODS alloys. •Powder forging is a promising route to fabricate ODS steels and permits development of compositions with up to 1.5% yttria.

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.

Effects of pressure on thermal transport in plutonium oxide powder

International Nuclear Information System (INIS)

Bielenberg, Patricia; Prenger, F. Coyne; Veirs, Douglas Kirk; Jones, Jerry

2004-01-01

Radial temperature profiles in plutonium oxide (PuO 2 ) powder were measured in a cylindrical vessel over a pressure range of 0.055 to 334.4 kPa with two different fill gases, helium and argon. The fine PuO 2 powder provides a very uniform self-heating medium amenable to relatively simple mathematical descriptions. At low pressures ( 2 powder has small particle sizes (on the order of 1 to 10 μm), random particle shapes, and high porosity so a more general model was required for this system. The model correctly predicts the temperature profiles of the powder over the wide pressure range for both argon and helium as fill gases. The effective thermal conductivity of the powder bed exhibits a pressure dependence at higher pressures because the pore sizes in the interparticle contact area are relatively small (less than 1 μm) and the Knudsen number remains above the continuum limit at these conditions for both fill gases. Also, the effective thermal conductivity with argon as a fill gas is higher than expected at higher pressures because the solid pathways account for over 80% of the effective powder conductivity. The results obtained from this model help to bring insight to the thermal conductivity of very fine ceramic powders with different fill gases.

Strength Improvement of Clay Soil by Using Stone Powder

OpenAIRE

Ahmed Sameer Abdulrasool

2015-01-01

Soil stabilization with stone powder is a good solution for the construction of subgrade for road way and railway lines, especially under the platforms and mostly in transition zones between embankments and rigid structures, where the mechanical properties of supporting soils are very influential. Stone powder often has a unique composition which justifies the need for research to study the feasibility of using this stone powder type for ground improvement applications. This paper presents re...

Weldability of powder-metallurgy molybdenum with low oxygen content

International Nuclear Information System (INIS)

Hiraoka, Yutaka; Okada, Masatoshi

1987-01-01

Relationships between the formation of weld pores and the chemical compositions in powder-metallurgy molybdenum were investigated. It is suggested that almost 100% of Ca and Mg form oxides. In contrast, Fe, Ni, Cr and Al, Si only partly form oxides. A powder-metallurgy molybdenum containing less than 84 at.ppm oxygen did not show any large weld pores. The reduction of the oxygen content was achieved by purifying the molybdenum powder. (orig.) [de

Developments with melt spun RE-Fe-B powder for bonded magnets

International Nuclear Information System (INIS)

Brown, D.N.; Chen, Z.; Guschl, P.; Campbell, P.

2006-01-01

Rapidly quenched isotropic rare earth iron boride (RE-Fe-B) powders have found many applications throughout the electronics, automotive and white goods industries. The magnetic performance, thermal stability, corrosion resistance and processability of a powder are important factors when selecting a RE-Fe-B powder for a particular application. For electronic devices that operate at ambient temperatures, high remanence (B r ) tends to be a priority and RE 2 Fe 14 B/α-Fe nanocomposite powder magnets are favoured. Alternatively, automotive applications tend to require greater thermal stability and corrosion resistance, which are satisfied by single-phase RE 2 Fe 14 B powder magnets with higher intrinsic coercivity (H ci ). This article reviews the performance of commercially available rapidly solidified RE-Fe-B powders and recent developments made to address the demands of applications

Aroma compounds in sweet whey powder.

Science.gov (United States)

Mahajan, S S; Goddik, L; Qian, M C

2004-12-01

Aroma compounds in sweet whey powder were investigated in this study. Volatiles were isolated by solvent extraction followed by solvent-assisted flavor evaporation. Fractionation was used to separate acidic from nonacidic volatiles. Gas chromatography/mass spectrometry and gas chromatography/olfactometry were used for the identification of aroma compounds. Osme methodology was applied to assess the relative importance of each aroma compound. The most aroma-intense free fatty acids detected were acetic, propanoic, butanoic, hexanoic, heptanoic, octanoic, decanoic, dodecanoic, and 9-decenoic acids. The most aroma-intense nonacidic compounds detected were hexanal, heptanal, nonanal, phenylacetaldehyde, 1-octen-3-one, methional, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, 2,3,5-trimethylpyrazine, furfuryl alcohol, p-cresol, 2-acetylpyrrole, maltol, furaneol, and several lactones. This study suggested that the aroma of whey powder could comprise compounds originating from milk, compounds generated by the starter culture during cheese making, and compounds formed during the manufacturing process of whey powder.

Induction investigations powder ittrium-barium cuprite

International Nuclear Information System (INIS)

Savchenko, O.V.; Savchenko, O.Ya.

1993-01-01

Behavior of magnetic moment of the YBa 2 Cu 3 O 7 powder has been studied in the pulsed and alternating magnetic field with the amplitude from 40 A/m to 4 kA/m at the temperature of liquid nitrogen boiling. The complex behavior of the magnetic moment is ascribed to the presence in the powder of two current carrying phases with the limit current densities differing by more than an order of magnitude. The magnetic field after-effect of several tens of kA/m on the powder results in the limit current density of the phase with reduced current density diminishes still further almost by an order of magnitude after the power exposure in the magnetic field. The direct magnetic field of several tens of kA/m practically completely suppresses the current in the phase with the reduced current density and noticeably reduces the fraction of the other phase

Ceramic UO2 powder production at Cameco Corporation

International Nuclear Information System (INIS)

Mulligan, J.J.

2005-01-01

This paper describes the various aspects of ceramic grade UO 2 powder production at Cameco Corporation's Port Hope conversion facility. It discusses the significant safety systems, production processes and plant monitoring and control systems. It also provides an insight into how various support groups such as Quality Assurance, Analytical Services, and Technology Development contribute to the consistent production of high quality UO 2 powder. The ability of Cameco to identify, measure and control the physical and chemical properties of ceramic grade UO 2 has resulted in the production of uniform quality powder that has consistently met customer requirements. (author)

Gas adsorption during storage of plutonium dioxide powders

International Nuclear Information System (INIS)

Cuillerdier, C.; Cossonnet, C.; Germain, M.

1984-10-01

Adsorption phenomena occuring in plutonium dioxide containers are studied for the determination of safe conditions for storage and transportation of plutonium dioxide powders. Adsorption on dried PuO 2 of air individual gases, influence of powder isotopic composition, chemisorption, effect of moisture are determined. Adsorption of dry air obeys an Elovich's law for its kinetics it is greatly exchange by α radiolysis. Pressure in the container can be reduced by storage under dry inert gas (Ar), decreasing the PuO 2 load and using powder containing preadsorbed water or wet air then radiolysis may occur (H 2 formation)

Metallization of uranium oxide powders by lithium reduction

International Nuclear Information System (INIS)

Kim, I. S.; Seo, J. S.; Oh, S. C.; Hong, S. S.; Lee, W. K.

2002-01-01

Laboratory scale experiments on the reduction of uranium oxide powders into metal by lithium were performed in order to determine the equipment setup and optimum operation conditions. The method of filtration using the porous magnesia filter was introduced to recover uranium metal powders produced. Based on the laboratory scale experimental results, mock-up scale (20 kg U/batch) metallizer was designed and made. The applicability to the metallization process was estimated with respect to the thermal stability of the porous magnesia filter in the high temperature molten salt, the filtration of the fine uranium metal powders, and the operability of the equipment

Karakterisasi Permen Jeli yang Dibuat dari Hasil Formulasi Jelly Powder

Directory of Open Access Journals (Sweden)

Ellya Sinurat

2010-06-01

Full Text Available Penelitian karakterisasi permen jeli dengan bahan baku formula jelly powder telah dilakukan. Formula jelly powder terdiri dari campuran karaginan murni, konjak, dekstrosa, dan KCl. Jelly powder ini digunakan untuk pembuatan permen jeli dengan variasi 3,5; 4,0; 4,5; dan 5,0%. Sebagai pembanding digunakan produk permen jeli impor berbahan dasar karaginan yang sudah ada di pasaran. Untuk mengetahui kualitas permen jeli, parameter yang diamati meliputi aktivitas air, sifat fisik (kekerasan, kelengketan, dan elastisitas serta nilai organoleptik (kenampakan, bau, rasa, tekstur, elastisitas, transparansi, dan penerimaan. Hasil penelitian menunjukkan bahwa semakin tinggi konsentrasi  jelly powder menyebabkan meningkatnya kekerasan, kelengketan, dan elastisitas permen jeli. Nilai organoleptik untuk rasa, tekstur, elastisitas, transparansi, dan penerimaan yang paling baik menurut panelis adalah pada konsentrasi jelly powder 4,5%

Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating

International Nuclear Information System (INIS)

Zhang, H.J.; Zhang, H.T.; Wu, X.W.; Wang, Z.L.; Jia, Q.L.; Jia, X.L.

2006-01-01

Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO 4 aqueous solution by electroless plating method. The factors including concentration of NiSO 4 , bathing temperature, ratio of hydrazine hydrate to NiSO 4 , the pH of the solution, etc., on influence of the yield and average particle size of metallic Ni ultrafine powders were studied in detail. X-ray powders diffraction patterns show that the nickel powders are cubic crystallite. The average crystalline size of the ultrafine nickel powders is about 30 nm. The dielectric and magnetic loss of ultrafine Ni powders-paraffin wax composites were measured by the rectangle waveguide method in the range 8.2-12.4 GHz. The factors for Ni ultrafine powders preparation are optimized by computer pattern recognition program based on principal component analysis, the optimum factors regions with higher yield of metallic Ni ultrafine powders are indicated by this way

Sintered FeCuRe Alloys Produced from Commercially Available Powders

Directory of Open Access Journals (Sweden)

Borowiecka-Jamrozek J.

2017-09-01

Full Text Available This paper discusses the mechanical properties of materials fabricated from commercially available powders designed for use as a metal matrix of diamond-impregnated composites. The powders with the catalogue numbers CSA and CSA800 produced in China were tested under laboratory conditions. The specimens were fabricated in a graphite mould using hot pressing. The materials were analysed for density, porosity, hardness and static tensile strength. A scanning electron microscope (SEM was employed to observe the microstructure and fracture surfaces of the specimens. The experimental data was used to determine how the chemical composition of the powders and the process parameters affected the microstructure and properties of the materials. The properties of the sintered materials produced from the Chinese powders were compared with the properties reported for specimens fabricated from cobalt powder (Co SMS. Even though the hot pressed CSA and CSA800 powders had inferior mechanical properties to their cobalt analogue, they seem well-suited for general-purpose diamond-impregnated tools with less demanding applications.

Computer Vision and Machine Learning for Autonomous Characterization of AM Powder Feedstocks

Science.gov (United States)

DeCost, Brian L.; Jain, Harshvardhan; Rollett, Anthony D.; Holm, Elizabeth A.

2017-03-01

By applying computer vision and machine learning methods, we develop a system to characterize powder feedstock materials for metal additive manufacturing (AM). Feature detection and description algorithms are applied to create a microstructural scale image representation that can be used to cluster, compare, and analyze powder micrographs. When applied to eight commercial feedstock powders, the system classifies powder images into the correct material systems with greater than 95% accuracy. The system also identifies both representative and atypical powder images. These results suggest the possibility of measuring variations in powders as a function of processing history, relating microstructural features of powders to properties relevant to their performance in AM processes, and defining objective material standards based on visual images. A significant advantage of the computer vision approach is that it is autonomous, objective, and repeatable.

Swelling of radiation-cured polymer precursor powder for silicon carbide by pyrolysis

Directory of Open Access Journals (Sweden)

Akinori Takeyama

2015-12-01

Full Text Available Ceramic yield, density, volume change and pore size distribution were measured for radiation- and thermally cured PCS powder when they were pyrolyzed in the temperature range of 673–973 K. Higher ceramic yield was obtained for radiation-cured powder due to smaller amount of evolved gas. Temperature dependence of volume change and the total pore volume show that the formation and disappearance of pores in the powders were determined by the volume shrinkage and evolution of decomposed gases. Volume shrinkage narrowed the pore size distribution for radiation-cured powder. For thermally cured powder, the narrowing of size distribution was disturbed by aggregated pores. Smaller amount of evolved gas from radiation-cured powder relative to thermally cured powder prevented the aggregation of pores and provided the narrow size distribution.

The magnetic properties of powdered and compacted microcrystalline permalloy

International Nuclear Information System (INIS)

Kollar, P.; Oleksakova, D.; Fuezer, J.; Kovac, J.; Roth, S.; Polanski, K.

2007-01-01

The aim of this work is to investigate the magnetic properties of powdered and compacted microcrystalline Ni-Fe (81 wt% of Ni) permalloy. It was found by investigating the influence of mechanical milling on the magnetic properties of powder samples prepared by milling of the ribbon that the alloy remains a solid solution with stable structure during the whole milling process. With decreasing particle size the rotation of magnetization vector gradually becomes dominant magnetization process and thus coercivity increases. After compaction of the powder by uniaxial hot pressing the magnetic contact between powder particles is recreated and for resulting bulk the displacement of the domain walls becomes dominant magnetization process with coercivity of 11 A/m (comparable with the coercivity of conventional permalloy)

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.

effect of chronic consumption of powdered tobacco (snuff)

African Journals Online (AJOL)

Uwaifoh

2012-12-31

Dec 31, 2012 ... The effect of chronic consumption of tobacco powder on anxiety, fear and social ... only, while the test group received mixed feed of 1gram powdered tobacco per ..... alkaloid, nicotine decrease tension and depressive feelings and promote the ... Ethnologically based animal models of anxiety disorders.

Menu Proposal to Use Powdered Agar

OpenAIRE

土屋, ひろ子; 嶋村, 桃子; 小松, 沙霧

2015-01-01

The author was involved in the development of the menu items that might be sold at “Taisho Village”, a theme park. Requirements in the menu development were that cooking should be simple as it starts cooking after receiving orders and it should have attractive appearances. Powdered agar has advantages over rod-shaped or string-shaped agar, with easiness of handling such as its ready solubility in water and no need to wash, rehydrate or strain. Because powdered agar is easy to use in cooking,...

Fluidization bed coating of copper bars with epoxy powder

OpenAIRE

Soh, Chiaw Min

2014-01-01

Fluidized bed coating (FBC) is a process where preheated material is dipped into a flowing liquid bed of powder. Although FBC has existed for more than half a century, however there is little knowledge about the fluidized bed design that gives excellent fluidization quality as well as reducing powder entrainment. The objectives of this thesis are to investigate the effect of two different types of distributor with different pressure drop on powder coating, hydrodynamics of fluidized bed coati...

Production of titanium alloy powders by vacuum fusion-centrifugation

International Nuclear Information System (INIS)

Decours, Jacques; Devillard, Jacques; Sainfort, G.

1975-01-01

This work presents a method of preparing powdered TA6V and TA6Z5D alloys by fusion-centrifugation under electron bombardment. An industrial capacity apparatus for the production of metallic powders is described and the characteristics of the powders obtained are presented. Solid parts were shaped by sintering and drawing at temperatures between 850 and 1100 deg C. The structure and mechanical properties of the cold densified products before and after heat treatment are compared [fr

High yttria ferritic ODS steels through powder forging

Science.gov (United States)

Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

2017-05-01

Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y2O3 (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility.

Characterization of prealloyed copper powders treated in high energy ball mill

International Nuclear Information System (INIS)

Rajkovic, Viseslava; Bozic, Dusan; Jovanovic, Milan T.

2006-01-01

The inert gas atomised prealloyed copper powders containing 3.5 wt.% Al were milled up to 20 h in the planetary ball mill in order to oxidize aluminium in situ with oxygen from the air. In the next procedure compacts from milled powder were synthesized by hot-pressing in argon atmosphere. Compacts from as-received Cu-3.5 wt.% Al powder and electrolytic copper powder were also prepared under the same conditions. Microstructural and morphological changes of high energy milled powder as well as changes of thermal stability and electrical conductivity of compacts were studied as a function of milling time and high temperature exposure at 800 deg. C. Optical, scanning electron microscopy (SEM) and X-ray diffraction analysis were performed for microstructural characterization, whereas thermal stability and electrical conductivity were evaluated by microhardness measurements and conductometer Sigmatest, respectively. The prealloyed 5 h-milled and compacted powder showed a significant increase in microhardness reaching the value of 2600 MPa, about 4 times greater than that of compacts synthesized from as-received electrolytic copper powder (670 MPa). The electrical conductivity of compacts from 5 h-milled powder was 52% IACS. The results were discussed in terms of the effect of small grain size and finely distributed alumina dispersoids on hardening and thermal stability of compacts

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.

Positron lifetime studies on thorium oxide powders

International Nuclear Information System (INIS)

Upadhyaya, D.D.; Muraleedharan, R.V.; Sharma, B.D.

1982-01-01

Positron lifetime spectra have been studied for ThO 2 powders, calcined at different temperatures and having different particle sizes. Three lifetime components could be resolved, the longest component being of low intensity. An observed strong dependence on the particle size of the annihilation process and the variation of positronium diffusion constant is explained on the basis of defect density variations in these powders. (author)

Injection molding of Y-TZP powders prepared by colloidal processing

International Nuclear Information System (INIS)

Kimura, Y.; Mineshita, O.; Kaga, T.; Tokinaga, T.; Obitsu, M.

1991-01-01

TZP powders containing 3mol% Y 2 O 3 were prepared from ZrOCl 2 solution via an aqueous colloidal suspension of ZrO 2 . Processing variables were optimized to obtain powders suitable for injection molding. Wettability of powders with binders, fluidity of melting compound, removal of binder from green body, and properties of sintered body were investigated

Direct laser sintering of metal powders: Mechanism, kinetics and microstructural features

International Nuclear Information System (INIS)

Simchi, A.

2006-01-01

In the present work, the densification and microstructural evolution during direct laser sintering of metal powders were studied. Various ferrous powders including Fe, Fe-C, Fe-Cu, Fe-C-Cu-P, 316L stainless steel, and M2 high-speed steel were used. The empirical sintering rate data was related to the energy input of the laser beam according to the first order kinetics equation to establish a simple sintering model. The equation calculates the densification of metal powders during direct laser sintering process as a function of operating parameters including laser power, scan rate, layer thickness and scan line spacing. It was found that when melting/solidification approach is the mechanism of sintering, the densification of metals powders (D) can be expressed as an exponential function of laser specific energy input (ψ) as ln(1 - D) = -Kψ. The coefficient K is designated as 'densification coefficient'; a material dependent parameter that varies with chemical composition, powder particle size, and oxygen content of the powder material. The mechanism of particle bonding and microstructural features of the laser sintered powders are addressed

Improving resistance welding of aluminum sheets by addition of metal powder

DEFF Research Database (Denmark)

Al Naimi, Ihsan K.; Al-Saadi, Moneer H.; Daws, Kasim M.

2015-01-01

. The improvement obtained is shown to be due to the development of a secondary bond in the joint beside the weld nugget increasing the total weld area. The application of powder additive is especially feasible, when using welding machines with insufficient current capacity for producing the required nugget size......In order to ensure good quality joints between aluminum sheets by resistance spot welding, a new approach involving the addition of metal powder to the faying surfaces before resistance heating is proposed. Three different metal powders (pure aluminum and two powders corresponding to the alloys AA....... In such cases the best results are obtained with pure aluminum powder....

Powder neutron diffractometers

International Nuclear Information System (INIS)

Adib, M.

2002-01-01

Basic properties and applications of powder neutron Diffractometers are described for optimum use of the continuous neutron beams. These instruments are equipped with position sensitive detectors, neutron guide tubes, and both high intensity and high resolution modes of operation are possible .The principles of both direct and Fourier reverse time-of-flight neutron Diffractometers are also given

The development of an alternative thermoplastic powder prepregging technique

Science.gov (United States)

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

1992-01-01

An alternative powder prepregging technique is discussed that is based on the deposition of powder onto carbon fibers that have been moistened using an ultrasonic humidifier. The dry fiber tow is initially spread to allow a greater amount of the fiber surface to be exposed to the powder, thus ensuring a significant amount of intimate contact between the fiber and the matrix. Moisture in the form of ultrafine water droplets is then deposited onto the spread fiber tow. The moisture promotes adhesion to the fiber until the powder can be tacked to the fibers by melting. Powdered resin is then sieved onto the fibers and then tacked onto the fibers by quick heating in a convective oven. This study focuses on the production of prepregs and laminates made with LaRC-TPI (thermoplastic polyimide) using this process. Although the process appears to be successful, early evaluation was hampered by poor interfacial adhesion. The adhesion problem, however, seems to be the result of a material system incompatibility, rather than being influenced by the process.

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.

Coating of ceramic powders by chemical vapor deposition techniques (CVD)

International Nuclear Information System (INIS)

Haubner, R.; Lux, B.

1997-01-01

New ceramic materials with selected advanced properties can be designed by coating of ceramic powders prior to sintering. By variation of the core and coating material a large number of various powders and ceramic materials can be produced. Powders which react with the binder phase during sintering can be coated with stable materials. Thermal expansion of the ceramic materials can be adjusted by varying the coating thickness (ratio core/layer). Electrical and wear resistant properties can be optimized for electrical contacts. A fluidized bed reactor will be designed which allow the deposition of various coatings on ceramic powders. (author)

Liquid coated melt-spun Nd-Fe-B powders for bonded magnets

Science.gov (United States)

Li, D.; Gaiffi, S.; Kirk, D.; Young, K.; Herchenroeder, J.; Berwald, T.

1999-04-01

The liquid coating (LC) has been employed to apply epoxy and lubricant over the surface of rapidly solidified Nd-Fe-B powder particles. The LC led to an improvement of physical and magnetic properties for the powders and magnets compared to the dry blending and the encapsulation methods. The LC powders have excellent flowability and can be used for bonded magnets requiring very close tolerances; further bonded magnets made using this powder posses higher strength.

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.

Dry Powder Precursors of Cubic Liquid Crystalline Nanoparticles (cubosomes)

International Nuclear Information System (INIS)

Spicer, Patrick T.; Small, William B.; Small, William B.; Lynch, Matthew L.; Burns, Janet L.

2002-01-01

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

Homogeneity of blended nuclear fuel powders after pneumatic transport

International Nuclear Information System (INIS)

Smeltzer, E.E.; Skriba, M.C.; Lyon, W.L.

1982-01-01

A study of the pneumatic transport of fine (approx. 1μm) cohesive nuclear fuel powders was conducted for the U.S. Department of Energy to demonstrate the feasibility of this method of transport and to develop a design data base for use in a large scale nuclear fuel production facility. As part of this program, a considerable effort was directed at following the homogeneity of blended powders. Since different reactors require different enrichments, blending and subsequent transport are critical parts of the fabrication sequence. The various materials used represented analogs of a wide range of powders and blends that could be expected in a commercial mixed oxide fabrication facility. All UO 2 powders used were depleted and a co-precipitated master mix of (U, Th)O 2 was made specifically for this program, using thorium as an analog for plutonium. In order to determine the effect of pneumatic transport on a blended powder, samples were taken from a feeder vessel before each test, and from a receiver vessel and a few line sections after each transfer test. The average difference between the before and after degree of non-homogeneity was < 1%, for the 21 tests considered. This shows that overall, the pneumatic transport of blended, fine nuclear fuel powders is possible, with only minor unblending occurring

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...

Pyrophoric behaviour of uranium hydride and uranium powders

Science.gov (United States)

Le Guyadec, F.; Génin, X.; Bayle, J. P.; Dugne, O.; Duhart-Barone, A.; Ablitzer, C.

2010-01-01

Thermal stability and spontaneous ignition conditions of uranium hydride and uranium metal fine powders have been studied and observed in an original and dedicated experimental device placed inside a glove box under flowing pure argon. Pure uranium hydride powder with low amount of oxide (Oxidation mechanisms are proposed.

Changes in UO2 powder properties during processing via BNFL's binderless route

International Nuclear Information System (INIS)

Bromely, A.P.; Logsdon, R.; Roberts, V.A.

1997-01-01

The Short Binderless Route (SBR) has been developed for Mixed Oxide fuel production in BNFL's MOX Demonstration Facility (MDF) and the Sellafield MOX Plant (SMP). It is a compact process which enables good homogenisation of the Pu/U mixture and production of free flowing press feed materials. The equipment used to achieve this consists of an attritor mill to provide homogenization and a spheroidiser to provide press feed granules. As for other powder processes, the physical properties of the UO 2 powder can affect the different process stages and consequently a study of some of these effects has been carried out. The aim of the work were to gain a better understanding of the process, to consequently optimize press feed material quality and to also maintain powder hold-up levels in the equipment at a minimum. The paper considers the effects of milling processes on powder morphology and powder surface effects, on the granulation process and also on powder and granule bulk properties such as pour, tap and compaction densities. Results are discussed in terms of powder properties such as powder cohesivity, morphology and particle size. UO 2 powder derived from both the Integrated Dry Route (IDR) and the Ammonium Di-Uranate (ADU) Route are considered. Small (1 kg) scale work has been carried out which has been confirmed by larger (25 kg) scale trials. The work shows that IDR powder with differing morphologies and ADU powder can be successfully processed via the SBR route. (author). 4 figs, 4 tabs

Studies of two stage gas turbine combustor for biomass powder. Part 1, Atmospheric cyclone gasification experiments with wood powder. Technical report

Energy Technology Data Exchange (ETDEWEB)

Degerman, Bengt; Hedin, Johan; Fredriksson, Christian; Kjellstroem, Bjoern; Salman, Hassan [Luleaa Univ. of Technology (Sweden). Dept. of Mechanical Engineering

2000-10-01

This report summarises the research and development work regarding development of a two stage gas turbine combustor for wood powder carried out at the Luleaa University of Technology from July 1993 to December 1996. The process being studied is based on cyclone gasification of the wood powder and combustion of the product gas in a suitably adapted gas turbine combustion chamber, without other gas cleaning than that obtained by the cyclone. A critical issue to be studied in the project is if the burned gases from such a cyclone gasifier lead to acceptably low deposition rates for K- and Na-compounds in a gas turbine with 850 deg C inlet temperature. The project strategy has been to study wood powder feeding and cyclone gasification first at atmospheric pressure, then run separate pressurised cyclone gasification tests for studies of the possibilities to achieve stable operation when the air flow is supplied by a separate compressor and finally to run integrated gasifier/gas turbine tests for studies of the deposition problem in practical operation. During the period covered by this report the atmospheric test facility has been designed, built and commissioned. It has been used mainly for studies of injector feeding of wood powder into a cyclone gasifier and for gasification experiments where in particular the fate of ash elements introduced with the wood powder has been studied. The results of these experiments have shown that steam injection of wood powder is possible with a steam consumption of about 0.3 kg steam/kg wood. The effects of injector geometry on the performance has also been studied. The gasification experiments show clearly that ash elements, including K and Na remain in the ash until very late in the thermal conversion process, also at gas temperatures exceeding 900 deg C. The separation of K with the cyclone bottom char has been 50 - 60% and the separation of Na about 80% with the cyclone geometry and the wood powder tested. The resulting load of K

Superconducting properties of in situ powder-in-tube-processed MgB{sub 2} tapes fabricated with sub-micrometre Mg powder prepared by an arc-plasma method

Energy Technology Data Exchange (ETDEWEB)

Yamada, H [Maglev System Development Division, Central Japan Railway Company, 1545-33, Ooyama, Komaki, Aichi 485-0801 (Japan); Uchiyama, N [Maglev System Development Division, Central Japan Railway Company, 1545-33, Ooyama, Komaki, Aichi 485-0801 (Japan); Matsumoto, A [Superconducting Materials Center, National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Kitaguchi, H [Superconducting Materials Center, National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Kumakura, H [Superconducting Materials Center, National Institute for Materials Science, 1-2-1, Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

2007-01-15

We fabricated in situ powder-in-tube-processed MgB{sub 2}/Fe tapes using sub-micrometre Mg powder prepared by applying an arc-plasma method. We found that the use of this sub-micrometre Mg powder was very effective in increasing the J{sub c} values. The transport J{sub c} value of 10 mol% SiC-added tapes fabricated with this sub-micrometre Mg powder reached 275 A mm{sup -2} at 4.2 K and 10 T. This value was about six times that of 5 mol% SiC-added tapes fabricated with commercial Mg powder. Microstructure analyses suggest that this J{sub c} enhancement is primarily due to the smaller MgB{sub 2} grain size.

The study of characteristics of powders of polymers for 3D printing

Directory of Open Access Journals (Sweden)

Yu. F. Shutilin

2017-01-01

Full Text Available One of the biggest challenges is to find ways of recovering the expensive powder. With this aim, we needed to find out what happens with polyamide powder in the chamber of the printer and what processes affect raw materials, thereby impairing the physico-mechanical properties. In order to answer these questions, we conducted a number of studies. Articles of mixtures with a high aspect ratio of the secondary powder lose their properties: their surface is rough, increased fragility, there is a possibility of deformation of details. We carried out studies of the powder based on polyamide-12, applied by JSC "Center of technological competence of additive technologies" of the city of Voronezh, brand PA2200 modified. Material white powder, odourless. An increase in the degree of crystallinity from recycled polymer is considered an anomaly. But the violation of this trend due to the peculiarities of the technology of selective laser sintering. Thus, prolonged exposure of the powder in the chamber at a temperature close to the melting point, followed by a long cooling to room temperature represents the ideal conditions for the growth of crystalline phase. The research was able to identify differences due to deterioration of the physico-chemical properties of the powder after processing. The most important is the agglomeration of particles of the secondary powder in relation to the primary. In this regard, powder, already passed the stage of processing, an increase in the melting temperature, which causes defects in the fabricated parts: as the capacity of the carbon laser melting powder particles is fixed, its energy is not sufficient for the occurrence of the endothermic reaction caused by melting of the secondary powder. Thus, the powder particles only partially fused, whereby the resulting products of the observed increase in fragility.

Time-resolved Neutron Powder Diffraction

International Nuclear Information System (INIS)

Pannetier, J.

1986-01-01

The use of a high-flux neutron source together with a large position sensitive detector (PSD) allows a powder diffraction pattern to be recorded at a time-scale of a few minutes so that crystalline systems under non-equilibrium conditions may now conveniently be investigated. This introduces a new dimension into powder diffraction (the time and transient phenomena like heterogeneous chemical reactions can now be easily studied. The instrumental parameters relevant for the design of such time-dependent experiments are briefly surveyed and the current limits of the method are discussed. The applications are illustrated by two kinds of experiment in the field of inorganic solid state chemistry: true kinetic studies of heterogeneous chemical reactions and thermodiffractometry experiments

Yttrium orthoferrite powder obtained by the mechanochemical synthesis

Directory of Open Access Journals (Sweden)

Lazarević Zorica Ž.

2017-01-01

Full Text Available Yttrium orthoferrite (YFeO3 powder was prepared by a mechanochemical synthesis from a mixture of Y2O3 and α-Fe2O3 powders in a planetary ball mill for 2.5 h. The obtained YFeO3 powder sample was characterized by X-ray diffraction (XRD, Raman and infrared spectroscopy. The average crystallite size calculated by the Scherrer equation was 12 nm. The Mössbauer spectroscopy at room temperature confirms the superparamagnetic character of YFeO3 orthoferrite sample. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45003, Grant no. III 45015, Grant no. III 45018

Extinguisher powder for liquid metal fires

Energy Technology Data Exchange (ETDEWEB)

Menzenhauer, P; Ochs, G [Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Reaktorentwicklung

1978-11-01

The extinguisher introduced here based on graphite exhibited considerably improved extinguishing properties compared to other extinguishing powders. It has no aggressive properties, is, as for as could be tested in the short time available, non-hygroscopic and thus very easy to remove after extinguishing and cooling of the fire. The amount of extinguisher necessary is only a fraction of the amounts needed of other common powders. Storage is no problem and nerely a small storage amount is required. This extinguisher is excellently suitable for fighting sodium surface fires.

Extinguisher powder for liquid metal fires

International Nuclear Information System (INIS)

Menzenhauer, P.; Ochs, G.

1978-01-01

The extinguisher introduced here based on graphite exhibited considerably improved extinguishing properties compared to other extinguishing powders. It has no aggressive properties, is, as for as could be tested in the short time available, non-hygroscopic and thus very easy to remove after extinguishing and cooling of the fire. The amount of extinguisher necessary is only a fraction of the amounts needed of other common powders. Storage is no problem and nerely a small storage amount is required. This extinguisher is excellently suitable for fighting sodium surface fires. (orig./HP) [de

Efficacy of undecylenic acid-zinc undecylenate powder in culture positive tinea pedis.

Science.gov (United States)

Chretien, J H; Esswein, J G; Sharpe, L M; Kiely, J J; Lyddon, F E

1980-01-01

One hundred fifty-one patients with tinea pedis participated in a double-blind study to assess the efficacy and safety of a powder containing undecylenic acid 2% and zinc undecylenate 20% versus a placebo powder. Patients were assigned to apply twice-daily applications of either active powder or placebo for a period of 4 weeks. Trichophyton rubrum or Trichophyton mentagrophytes were isolated from pretreatment cultures of 85 patients. Of these, 88% treated with active powder had negative cultures after 4 weeks compared with 17% of those treated with placebo powder (p less than 0.001). Fungus was identified in potassium hydroxide (KOH) treated skin scrapings of all 151 patients before treatment. Of those treated with active powder, 80% were KOH negative after 4 weeks compared with 49% of those treated with placebow powder (p = 0.001). Erythema and scaling were significantly improved by therapy with active powder, as were subjective evaluations of itching and burning. There were no side-effects or adverse reactions to undecylenic acid and its zinc salt.

Synthesis of ultrafine alumina powders using egg white as complexing medium

International Nuclear Information System (INIS)

Salem, R.E.P.; Guilherme, K. A.; Chinelatto, A.S.A.; Chinelatto, A.L.

2011-01-01

Synthesis of alumina powders through chemical methods has been attracting much attention of researchers in the past few years, due to the ability to produce powders in nanometric scale with high degree of purity. In this work, there were synthesized alumina powders through a chemical route, using egg white as a complexing medium and aluminium nitrate as the source of Al 3+ cations. Egg white contains ovalbumin, a protein which acts effectively on the isolation of aluminium cations during the mixing process, enabling the formation of ultrafine alumina powders in a relatively economic and environmentally friendly way. The powders obtained by calcinations of the precursor resin were characterized by X-ray diffraction, specific surface area measurements, infrared spectroscopy and scanning electron microscopy. It was observed that the egg white, present at the reaction medium, allowed obtaining transition alumina powders, with high degree of purity. (author)

Examination of Zinc Oxide Nanoparticles as a Fluorescent Fingerprint Detection Powder

International Nuclear Information System (INIS)

Tun Tun Lin

2010-12-01

Detection of latent fingerprint was performed using zinc oxide nanoparticles which were produced by simple and efficient method in aqueous media from zinc nitrate. Synthesized ZnO nanoparticles were characterized by XRD, SEM and AFM for ZnO purification and particle size examination. In this paper an effort has been made to compare the results of using ZnO nanoparticles and conventional fingerprint powders such as ZnO bulk powder, CaO, TiO2, printer toner powder and graphite. Fingerprints on different materials were also examined by the use of ZnO and Graphite powder, which is currently used in the Central Intelligence Department of Myanmar Police Force.From this research, it was observed that zinc oxide nanoparticles powder produced a much clearer picture of the fingerprints, compared to conventional powders and it has very good quality at sticking to the fingerprint residue but not to the background surface.

LEU fuel powder technology at Babcock and Wilcox (USA)

International Nuclear Information System (INIS)

Bogacik, K.E.

1984-01-01

This paper traces BandW involvement in HEU fuel manufacturing to the current work directed at LEU reactor technology. Past work at BandW in areas such as alloying, fuel handling and core manufacturing has been of significant benefit to the current LEU fuel processing requirements. Recent investigations and process developments for production of LEU aluminide and silicide fuels are discussed. Techniques for alloying by vacuum are melting, followed by comminution methods after alloying, are presented for both the LEU aluminide and silicide fuel powders. Powder processing discussions include compacting techniques used by BandW for these alloys. This overview of BandW's LEU i nvolvement provides details of specific modifications and process developments in powdered fuels. Product attributes such as powder chemistry, size, and other physical properties of each LEU fuel are presented. (author)

Properties of 40N3M powder structural steel

International Nuclear Information System (INIS)

Moskvina, T.P.; Gulyaev, A.P.; Gulyaev, I.A.; Byakov, S.V.; Melent'ev, I.V.; Morgun, G.N.

1984-01-01

Effect of the fabrication technique of compact slabs made of the 40N3M powder structural steel on mechanical properties with determination of a cold brittleness threshold was studied. It is established that after a thermal treatment at a density close to 100% a powder steel is sufficiently close to steel, rolled of an ingot, but is second in reference to steel in its ductility and impact strength. Properties of powder steel obtained by the method of dynamic hot forming (DHF) and hot extrusion are practically equal, but the first method has definite advantages as it allows to obtain details with a definitive form. The above investigation permits to recommend an application of the 40N3M powder steel fabricated by the DHF methods. The optimum thermal treatment course is: quenching+high annealing

Validation of a realistic powder sample using data from DMC at PSI

International Nuclear Information System (INIS)

Willendrup, Peter; Filges, Uwe; Keller, Lukas; Farhi, Emmanuel; Lefmann, Kim

2006-01-01

We present results of a virtual experiment, carried out by means of a McStas simulation of the powder diffractometer DMC at PSI, using the new powder sample component PowderN. This powder component takes tabulated crystallographic input to define realistic powder lines. The simulated output data from the virtual experiment on the compound Na 2 Ca 3 Al 2 F 14 are compared to real measurement data from the DMC instrument. The agreement is very good with respect to peak positions, widths, background intensity and relative peak intensities. This work represents an important step towards reliable virtual experiments and also act as a validation of the PowderN sample component in McStas

Validation of a realistic powder sample using data from DMC at PSI

Energy Technology Data Exchange (ETDEWEB)

Willendrup, Peter [Riso National Laboratory, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)]. E-mail: peter.willendrup@risoe.dk; Filges, Uwe [Laboratory for Development and Methods ETHZ and PSI CH-5232 Villigen PSI (Switzerland); Keller, Lukas [Laboratory for Neutron Scattering ETHZ and PSI CH-5232 Villigen PSI (Switzerland); Farhi, Emmanuel [Institut Laue-Langevin (ILL) Grenoble, 6 rue J. Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Lefmann, Kim [Riso National Laboratory, Frederiksborgvej 399, DK-4000 Roskilde (Denmark)

2006-11-15

We present results of a virtual experiment, carried out by means of a McStas simulation of the powder diffractometer DMC at PSI, using the new powder sample component PowderN. This powder component takes tabulated crystallographic input to define realistic powder lines. The simulated output data from the virtual experiment on the compound Na{sub 2}Ca{sub 3}Al{sub 2}F{sub 14} are compared to real measurement data from the DMC instrument. The agreement is very good with respect to peak positions, widths, background intensity and relative peak intensities. This work represents an important step towards reliable virtual experiments and also act as a validation of the PowderN sample component in McStas.

Validation of a realistic powder sample using data from DMC at PSI

DEFF Research Database (Denmark)

Willendrup, Peter Kjær; Filges, U.; Keller, L.

2006-01-01

We present results of a virtual experiment, carried out by means of a McStas simulation of the powder diffractometer DMC at PSI, using the new powder sample component PowderN. This powder component takes tabulated crystallographic input to define realistic powder lines. The simulated output data...... from the virtual experiment on the compound Na2Ca3Al2F14 are compared to real measurement data from the DMC instrument. The agreement is very good with respect to peak positions, widths, background intensity and relative peak intensities. This work represents an important step towards reliable virtual...... experiments and also act as a validation of the PowderN sample component in McStas....

Effect of pumpkin powder incorporation on cooking and sensory parameters of pasta

Directory of Open Access Journals (Sweden)

Lucia Minarovičová

2017-01-01

Full Text Available Pasta is commonly consumed and low glycaemic cereal-based food with long shelf life, which is suitable food matrix for substitution with functional ingredients. Pumpkin powder can be considered as suitable component in pasta making. The effect of addition of pumpkin powder at different levels (5, 7.5, and 10% on wheat dough rheology, cooking quality of pasta as well as on sensory properties was evaluated. Pumpkin powder included: 6.1% moisture, 8.2%, protein, 0.7% crude fat, 2.3% ash, 27.4% total dietary fiber which is included soluble (10.2% and insoluble (17.2% dietary fiber. Farinograph properties of pumpkin powder incorporated dough showed increase in water absorption and dough development time while dough stability and mixing tolerance indes were decreased. It was also observed that addition of pumpkin powder significantly altered cooking quality of pasta. Generally, pasta incorporated with pumpkin powder had shorter optimal cooking time. The shortest optimal time (5.9 min was after addition of 10% of pumpkin powder compared with control pasta (7.0 min. From the results also concluded that addition of pumpkin powder significantly increased cooking loss. The highest cooking loss (6.6% was after addition 10% pumpkin powder. Furthermore it could be stated that incorporation of pumpkin powder in pasta increased water absorption of pasta from 181.0% (control to 211.2% (10% of pumpkin powder. From sensory evaluation resulted that pumpkin powder incorporated pasta were characterized by lower colour, flavor and grain taste. On the other hand vegetable taste and granular structure of pasta increased with higher addition level of pumpkin powder. Moreover, it was concluded that pasta with addition level 10% were the most acceptable for accesors. Normal 0 21 false false false EN-GB X-NONE X-NONE Normal 0 21 false false false EN-GB X-NONE X-NONE

Radiation effects in high-disperse metal media and their application in powder metallurgy

International Nuclear Information System (INIS)

Zaykin, Y.A.; Aliyev, B.A.

2002-01-01

Experimental and theoretical results showing up effects of metal powder radiation processing, such as powder grinding, chemical refinement, and changes in powder particle surface state, are discussed. It is shown that preliminary irradiation of metal powders leads to profound structural alterations at all further stages of their processing by conventional methods of powder metallurgy and eventually effects the properties of the resulting product

Characterization of Ni ferrites powders prepared by plasma arc discharge process

Energy Technology Data Exchange (ETDEWEB)

Safari, A. [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University, Ahvaz (Iran, Islamic Republic of); Gheisari, Kh., E-mail: khgheisari@scu.ac.ir [Department of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University, Ahvaz (Iran, Islamic Republic of); Farbod, M. [Physics Department, Shahid Chamran University, Ahvaz (Iran, Islamic Republic of)

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. - Highlights: • Nanocrystalline Ni ferrite powders are prepared by plasma arc discharge process. • The mean particle size of the as-synthesized ceramic powders is about 100 nm. • The highest saturation magnetization is observed as zinc powders removed completely from the initial mixture.

Coercivity enhancement in HDDR near-stoichiometric ternary Nd–Fe–B powders

International Nuclear Information System (INIS)

Wan, Fangming; Han, Jingzhi; Zhang, Yinfeng; Wang, Changsheng; Liu, Shunquan; Yang, Jinbo; Yang, Yingchang; Sun, Aizhi; Yang, Fuqiang; Song, Renbo

2014-01-01

Anisotropic HDDR near-stoichiometric ternary Nd–Fe–B powders have been prepared. The coercivity of the powders was improved from 208.6 to 980.1 kA/m by the subsequent diffusion treatment using the Pr–Cu alloy. For comparison, Nd 11.5 Fe 80.7 B 6.1 Pr 1.2 Cu 0.5 alloy, in which Pr and Cu elements were directly added into the original Nd–Fe–B alloy, was also treated by the same HDDR process and the coercivity was only 557.3 kA/m. Microstructural investigations showed that a large area of (Nd, Pr)-rich phases concentrated at triangle regions in the HDDR Nd 11.5 Fe 80.7 B 6.1 Pr 1.2 Cu 0.5 powders, while the (Nd, Pr)-rich phases distributed uniformly in the diffusion treated powders. The uniform grain boundary layer can pin the motion of domain wall more effectively, resulting in a higher coercivity in diffusion treated HDDR Nd–Fe–B powders. - Highlights: • Anisotropic HDDR near-stoichiometric ternary Nd–Fe–B powders have been prepared. • The coercivity of the powders was improved from 2.62 to 12.31 kOe by the diffusion of Pr–Cu alloy. • The uniform grain boundary layer leads to a higher coercivity in diffusion treated powders

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.

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

Radiolysis characterization of chloramphenicol in powder and in eye ointment

International Nuclear Information System (INIS)

Hong, L.; Altorfer, H.R.

2005-01-01

The effects of γ-radiation sterilization on chloramphenicol, in both pure powder state and petrolatum eye ointment, were investigated with high performance liquid chromatography. The content of chloramphenicol decreases by 1.0% in powder state and by 1.2% in eye ointment at the reference radiation dose of 25 kGy. The profile of chloramphenicol radiolysis products in powder state differs from that in eye ointment. It was found that microenvironment of chloramphenicol molecule is a key factor governing the radiolysis of chloramphenicol in powder state. Solvent residues in chloramphenicol powder could change the radiolysis behavior of chloramphenicol. The solvents, having good solubility for chloramphenicol, promote radiolytic hydrolysis of chloramphenicol, but the converses do not. Inert gas purging or diffusion by exposing in absorbent is efficient method to prevent chloramphenicol powder from radiolysis. The influence of the presence of oxygen was explored. Oxygen plays a role of scavenger and diminishes radiolysis of chloramphenicol. It was found that Nactyl-L-cysteine can protection chloramphenicol in eye ointment from radiolysis. Hydrophobic radiolysis products of chloramphenicol were observed in eye ointment part. Using scavengers and lower irradiation can be strategies to resist radiolysis of chloramphenicol in petrolatum eye ointment. (author)

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.

Modeling of magnetic particle orientation in magnetic powder injection molding

Science.gov (United States)

Doo Jung, Im; Kang, Tae Gon; Seul Shin, Da; Park, Seong Jin

2018-03-01

The magnetic micro powder orientation under viscous shear flow has been analytically understood and characterized into a new analytical orientation model for a powder injection molding process. The effects of hydrodynamic force from the viscous flow, external magnetic force and internal dipole-dipole interaction were considered to predict the orientation under given process conditions. Comparative studies with a finite element method proved the calculation validity with a partial differential form of the model. The angular motion, agglomeration and magnetic chain formation have been simulated, which shows that the effect of dipole-dipole interaction among powders on the orientation state becomes negligible at a high Mason number condition and at a low λ condition (the ratio of external magnetic field strength and internal magnetic moment of powder). Our developed model can be very usefully employed in the process analysis and design of magnetic powder injection molding.

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 ...

Molten salt synthesis of ZnNb2O6 powder

International Nuclear Information System (INIS)

Guo Liangzhai; Dai Jinhui; Tian Jintao; Zhu Zhibin; He Tian

2007-01-01

Pure ZnNb 2 O 6 powder was successfully prepared by the molten salt synthesis method using Nb 2 O 5 and ZnO as raw materials and a mixture of NaCl and KCl as the solvent. The phase form and morphology of the prepared powder were characterized by X-ray diffraction and scanning electron microscopy. The effect of reacting temperature on phase formation was investigated. The results indicated that the single phase ZnNb 2 O 6 powder can be obtained by the molten salt synthesis method at 600 deg. C, and the SEM photographs show that the grains of the powder are rod-like particles

Strontium-90 and cesium-137 in powdered milk

International Nuclear Information System (INIS)

1977-01-01

Japan Chemical Analysis Center has analysed the strontium-90 and cesium-137 content in powdered milk. The samples were purchased on the open market in Tokyo from the powdered milk producers. The analysis of Strontium-90 and Cesium-137 content was carried out using the method recommended by Science and Technology Agency. (author)

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 ...

Fundamentals of powder x-ray diffraction practice

International Nuclear Information System (INIS)

Raftery, T.

2002-01-01

Full text: The goal of powder Xray diffraction is to gain information about a specimen or sample. Key aspects of this goal are 1. the sample selection, preparation and presentation; 2. the data collection process and conditions; 3. the interaction between these and the interpretation of the data. The 'ideal' powder (or polycrystalline) xray diffraction sample is fine grained, randomly orientated, homogenous and representative. There exists standard sample selection and preparation techniques for powders - sometimes however, the required information must be gained by alternate sample selection and preparation techniques. While there are few variables in the data collection process, there are some significant ones such as matching diffractometer resolution and intensity to the data collection goal whether that is phase identity, quantitative analysis or structure refinement, etc. There are also options of optical arrangement (Bragg-Brintano versus parallel beam versus Debye-Scherrer). One important aspect of the collection process is the assessment of the data quality. Powder xray diffraction has many applications from the straight-forward confirmation of phase identity and purity to structural analysis. Some of these applications will be considered and the interaction between the goal of the application and aspects of sample selection. Copyright (2002) Australian X-ray Analytical Association Inc

Muonium in Al2O3 powder at low temperature

International Nuclear Information System (INIS)

Kiefl, R.F.; Warren, J.B.; Oram, C.J; Brewer, J.H.; Harshman, D.R.

1982-04-01

Measurements of muonium (μ + e - ) spin relaxation in a finely powdered sample of γ-Al 2 O 3 in a He (or Ne) atmosphere indicate that the muonium atoms escape the powder grains with a high efficiency at low temperatures (T < 30 K). The muonium spin relaxation rate is proportional to the fraction of the powder surface area not covered by adsorbed He (Ne)

Determination of size and shape distributions of metal and ceramic powders

International Nuclear Information System (INIS)

Jovanovic, DI.

1961-01-01

For testing the size and shape distributions of metal and ceramic uranium oxide powders the following method for analysing the grain size of powders were developed and implemented: microscopic analysis and sedimentation method. A gravimetry absorption device was constructed for determining the specific surfaces of powders

Proportioning of U3O8 powder

International Nuclear Information System (INIS)

Cermak, V.; Markvart, M.; Novy, P.; Vanka, M.

1989-01-01

The tests are briefly described or proportioning U 3 O 8 powder of a granulometric grain size range of 0-160 μm using a vertical screw, a horizontal dual screw and a vibration dispenser with a view to proportioning very fine U 3 O 8 powder fractions produced in the oxidation of UO 2 fuel pellets. In the tests, the evenness of proportioning was assessed by the percentage value of the proportioning rate spread measured at one-minute intervals at a proportioning rate of 1-3 kg/h. In feeding the U 3 O 3 in a flame fluorator, it is advantageous to monitor the continuity of the powder column being proportioned and to assess it radiometrically by the value of the proportioning rate spread at very short intervals (0.1 s). (author). 10 figs., 1 tab., 12 refs

Size and surface AREA analysis of some metallic and intermetallic powders

International Nuclear Information System (INIS)

Elmasry, M.A.A.; Elsayed, A.A.; Abadir, M.F.

1988-01-01

The powder characterization of three intermetallic compounds ( Cr B, B 4 c and S ib 4 ) and three metallic powders (Fe, Co, and Ni) has been performed. This included the determination of powder density, chemical analysis, impurity analysis, shape factor, particle size analysis and specific surface area. The particle size analysis for the six powders was carried out using three techniques, namely; the 0-23, the microtrac and the fisher sub sieve and size. It was found that the analysis of the two powders and deviates from the log-normal probability distribution and the deviation was corrected. The specific surface area of the powders was measured using the high speed surface area analysis (BET method), and it was also calculated from surface area analysis findings, the BET technique was found to give the highest specific surface area values, and was attributed to the inclusion of internal porosity in the measurement. 8 fig., 10 tab

The precursors effects on biomimetic hydroxyapatite ceramic powders.

Science.gov (United States)

Yoruç, Afife Binnaz Hazar; Aydınoğlu, Aysu

2017-06-01

In this study, effects of the starting material on chemical, physical, and biological properties of biomimetic hydroxyapatite ceramic powders (BHA) were investigated. Characterization and chemical analysis of BHA powders were performed by using XRD, FT-IR, and ICP-AES. Microstructural features such as size and morphology of the resulting BHA powders were characterized by using BET, nano particle sizer, pycnometer, and SEM. Additionally, biological properties of the BHA ceramic powders were also investigated by using water-soluble tetrazolium salts test (WST-1). According to the chemical analysis of BHA ceramic powders, chemical structures of ceramics which are prepared under different conditions and by using different starting materials show differences. Ceramic powders which are produced at 80°C are mainly composed of hydroxyapatite, dental hydroxyapatite (contain Na and Mg elements in addition to Ca), and calcium phosphate sulfide. However, these structures are altered at high temperatures such as 900°C depending on the features of starting materials and form various calcium phosphate ceramics and/or their mixtures such as Na-Mg-hydroxyapatite, hydroxyapatite, Mg-Whitlockit, and chloroapatite. In vitro cytotoxicity studies showed that amorphous ceramics produced at 80°C and ceramics containing chloroapatite structure as main or secondary phases were found to be extremely cytotoxic. Furthermore, cell culture studies showed that highly crystalline pure hydroxyapatite structures were extremely cytotoxic due to their high crystallinity values. Consequently, the current study indicates that the selection of starting materials which can be used in the production of calcium phosphate ceramics is very important. It is possible to produce calcium phosphate ceramics which have sufficient biocompatibility at physiological pH values and by using appropriate starting materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Antioxidant and antimicrobial activities of squid ink powder

Directory of Open Access Journals (Sweden)

Fatimah Zaharah, M.Y.

2017-10-01

Full Text Available Economic development in Malaysia has led to increasing quantity and complexity of generated waste or by-product. The main objective of this study is to investigate the antioxidant and antimicrobial activities of squid ink powder. The squid ink was collected from fresh squid and dried using freeze dryer before it was ground into powder. The yield of squid ink was 22.82% after freeze-drying which was 69.37g in amount. Proximate composition analysis as well as two total antioxidant activity assays named 2,2-diphenyl-1-picrylhydrazyl (DPPH assay and Ferric Reducing Antioxidant Power (FRAP assay, and antimicrobial analysis were done on the powdered squid ink. The proximate results of squid ink powder were 4.43 ± 0.29% moisture, 62.46 ± 0.62% protein, 3.96 ± 0.08% fat, and 9.29 ± 0.05% ash. Results of DPPH assay showed that water extraction of squid ink powder has the highest 94.87 ± 4.87%, followed by ethanol 67.57 ± 7.55%, and hexane extract 2.10 ± 1.18%. FRAP assay result presented the same trend with water extraction had the highest value of 929.67 ± 2.31 μmol Fe (II / g of sample extract, followed by ethanol extract 201.00 ± 26.29 μmol Fe (II per gram sample and hexane 79.67 ± 12.66 μmol Fe (II / g of sample extract. Both water and ethanol extract showed antimicrobial properties with inhibition range of 7 to 15 mm, respectively. Fresh squid ink had 1.254 × 103 colony forming unit per gram of sample of microbial content. Squid ink powder had protein as major compound and microbial content was below from standard value of fisheries products as stated in Food Act 1983 and Regulation 1985.

High-energy ball milling of powder B-C mixtures

International Nuclear Information System (INIS)

Ramos, Alfeu S.; Taguchi, Simone P.; Ramos, Erika C.T.; Arantes, Vera L.; Ribeiro, Sebastiao

2006-01-01

The present work reports on the preparation of B-10 at.% C and B-18 at.% C powders by high-energy ball milling and further heat treatment. The milling process was carried out in a planetary ball mill. Following the milling process, powder samples were heat-treated at 1200 deg. C for 4 h using inert atmosphere. The milled and heat-treated B-10C and B-18C powders were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. A reduction on the intensity of B and C peaks was noticed after milling for 2 h, probably due the fine powder particle sizes because the pronounced fracture mechanism during ball milling of brittle starting components. The XRD patterns of B-10C and B-18C powders milled for 6 h indicated the presence of other peaks, suggesting that a metastable structure could have been formed. After milling for 90 h, these unknown peaks were still present. A large amount of B 4 C was formed after heat treatment at 1200 deg. C for 4 h beside these unknown peaks

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.

Magnetic properties of lanthanum orthoferrite fine powders prepared ...

Indian Academy of Sciences (India)

Unknown

No segregated minority phases were seen when particles of different routes were subjected to EDX analysis. In figure 2 we show the SEM micrographs of all the powders prepared. Nearly spherical particles with clear grain boundary are observed for powder obtained by SS method (figure 2a). The size of the particles is in ...

Luminescent properties of Al2O3: Tb powders

International Nuclear Information System (INIS)

Esparza G, A.E.; Garcia, M.; Falcony, C.; Azorin N, J.

2000-01-01

In this work the photo luminescent and cathode luminescent characteristics of aluminium oxide (Al 2 O 3 ) powders impurified with terbium (Tb) were studied for their use in dosimetry. The optical, structural, morphological characteristics of the powders as function of variation in the impurity concentration and the annealing temperature will be presented. As regards the optical properties of powders (photoluminescence and cathode luminescence) it was observed a characteristic emission associated with radiative transitions between electron energy levels of terbium, the spectra associated with this emission consists of several peaks associated with such transitions. In the structural and morphological characterization (X-ray diffraction and scanning electron microscopy) it was appreciated that in accordance the annealing temperature of powders is augmented it is evident the apparition of certain crystalline phases. The results show that this is a promissory material for radiation dosimetry. (Author)

Optimization of Bread Enriched with Garcinia mangostana Pericarp Powder

Science.gov (United States)

Ibrahim, U. K.; Salleh, R. Mohd; Maqsood-ul-Hague, S. N. S.; Hashib, S. Abd; Karim, S. F. Abd

2018-05-01

The aim of present work is to optimize the formulation of bread enhanced with Garcinia mangostana pericarp powder with the combination of baking process conditions. The independent variables used were baking time (15 - 30 minutes), baking temperature (180 - 220°C) and pericarp powder concentration (0.5 - 2.0%). The physical and chemical properties of bread sample such as antioxidant activity, phenolic content, moisture analysis and colour parameters were studied. Bread dough without fortification of pericarp powder was used as control. Data obtained were analyzed by multiple regressions and the significant model such as linear and quadratic with variables interactions were used. As a conclusion, the optimum baking conditions were found at 213°C baking temperature with 23 minutes baking time and addition of 0.87% for Garcinia mangostana pericarp powder to the bread formulation.

User guide for the POLARIS powder diffractometer at ISIS

International Nuclear Information System (INIS)

Hull, S.; Mayers, J.

1989-11-01

The POLARIS spectrometer at ISIS is currently being scheduled for use as a high intensity, medium resolution powder diffractometer. The particularly high neutron flux on POLARIS enables experiments to be performed with comparatively short counting times or on small sample volumes. This ability has been exploited during kinetic experiments of phase changes, where diffraction data is collected whilst the furnace is heating up. The provision of a large detector bank at 2 θ ∼ 90 0 is particularly important for studies of powder samples at high pressures. This scattering geometry has significant advantages for experiments of this kind, as suitable collimation of the incident and outgoing beams eliminates scattering from the surrounding pressure transmitting medium. This guide is intended to give a short description of the POLARIS powder diffractometer and to provide the basic information required to perform a powder diffraction experiment. (author)

[Studies on the brand traceability of milk powder based on NIR spectroscopy technology].

Science.gov (United States)

Guan, Xiao; Gu, Fang-Qing; Liu, Jing; Yang, Yong-Jian

2013-10-01

Brand traceability of several different kinds of milk powder was studied by combining near infrared spectroscopy diffuse reflectance mode with soft independent modeling of class analogy (SIMCA) in the present paper. The near infrared spectrum of 138 samples, including 54 Guangming milk powder samples, 43 Netherlands samples, and 33 Nestle samples and 8 Yili samples, were collected. After pretreatment of full spectrum data variables in training set, principal component analysis was performed, and the contribution rate of the cumulative variance of the first three principal components was about 99.07%. Milk powder principal component regression model based on SIMCA was established, and used to classify the milk powder samples in prediction sets. The results showed that the recognition rate of Guangming milk powder, Netherlands milk powder and Nestle milk powder was 78%, 75% and 100%, the rejection rate was 100%, 87%, and 88%, respectively. Therefore, the near infrared spectroscopy combined with SIMCA model can classify milk powder with high accuracy, and is a promising identification method of milk powder variety.

Production of fine powder from silk by radiation

International Nuclear Information System (INIS)

Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu

2000-01-01

Silk fine power was prepared directly from silk fiber irradiated with an accelerated electron beam(EB). Irradiated silk fiber was well pulverized only by physical crushing using ball mill without any chemical pretreatment. Raw and degummed silk fibers were irradiated at ambient temperature in the dose range of 250-1000 kGy. Although unirradiated silk fibers were not pulverized at all, irradiated fibers were easily pulverized and showed higher conversion from fiber to powder for higher doses. The presence of oxygen in the irradiation atmosphere enhanced pulverization of silk fiber. Raw silk fibers were less pulverized compared to degummed ones. The electron microscope observation showed that the minimum particle size of silk powder obtained from fiber irradiated by 1000 kGy in oxygen was less than 10 microns. It was found that fibroin powder obtained in this work dissolved remarkably into cold water, thought unirradiated fibroin fiber had little solubility even in hot water. A typical soluble fraction was about 60% for fibroin powder obtained from fiber irradiated by 1000 kGy in oxygen. (author)

Nano-powder production by electrical explosion of wires

International Nuclear Information System (INIS)

Mao Zhiguo; Zou Xiaobing; Wang Xinxin; Jiang Weihua

2010-01-01

A device for nano-powder production by electrical explosion of wires was designed and built. Eight wires housed in the discharge chamber are exploded one by one before opening the chamber for the collection of the produced nano-powder. To increase the rate of energy deposition into a wire, the electrical behavior of the discharge circuit including the exploding wire was simulated. The results showed that both reducing the circuit inductance and reducing the capacitance of the energy-storage capacitor (keeping the storage energy constant) can increase the energy deposition rate. To better understand the physical processes of the nano-powder formation by the wire vapor, a Mach-Zehnder interferometer was used to record the time evolution of the wire vapor as well as the plasma. A thermal expansion lag of the dense vapor core as well as more than one times of the vapor burst was observed for the first time. Finally, nano-powders of titanium nitride, titanium dioxide, copper oxides and zinc oxide were produced by electrical explosion of wires. (authors)

Lactose hydrolysis and milk powder production: technological aspects

Directory of Open Access Journals (Sweden)

Jansen Kelis Ferreira Torres

2017-06-01

Full Text Available The food industry has the challenge and the opportunity to develop new products with reduced or low lactose content in order to meet the needs of a growing mass of people with lactose intolerance. The manufacture of spray dried products with hydrolyzed lactose is extremely challenging. These products are highly hygroscopic, which influence the productivity and conservation of the powders, not to mention the undesirable and inevitable technological problem of constant clogging of drying chambers. The aim of this study was to evaluate the effect of different levels (0%, 25%, 50%, 75% and > 99% of enzymatic lactose hydrolysis on the production and storage of whole milk powder. The samples were processed in a pilot plant and characterized in relation to their composition analysis; to their degree of hydrolysis of lactose; and to their sorption isotherms. The results indicated the hydrolysis of lactose may affect the milk powder production due to a higher extent of powder adhesion within the spray dryer chambers and due to a higher tendency to absorb water during storage.

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, Kazunari; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan)

2000-03-01

Silk fine power was prepared directly from silk fiber irradiated with an accelerated electron beam(EB). Irradiated silk fiber was well pulverized only by physical crushing using ball mill without any chemical pretreatment. Raw and degummed silk fibers were irradiated at ambient temperature in the dose range of 250-1000 kGy. Although unirradiated silk fibers were not pulverized at all, irradiated fibers were easily pulverized and showed higher conversion from fiber to powder for higher doses. The presence of oxygen in the irradiation atmosphere enhanced pulverization of silk fiber. Raw silk fibers were less pulverized compared to degummed ones. The electron microscope observation showed that the minimum particle size of silk powder obtained from fiber irradiated by 1000 kGy in oxygen was less than 10 microns. It was found that fibroin powder obtained in this work dissolved remarkably into cold water, thought unirradiated fibroin fiber had little solubility even in hot water. A typical soluble fraction was about 60% for fibroin powder obtained from fiber irradiated by 1000 kGy in oxygen. (author)

Preparation and Characterization of Nano-structured Ceramic Powders Synthesized by Emulsion Combustion Method

International Nuclear Information System (INIS)

Takatori, Kazumasa; Tani, Takao; Watanabe, Naoyoshi; Kamiya, Nobuo

1999-01-01

The emulsion combustion method (ECM), a novel powder production process, was originally developed to synthesize nano-structured metal-oxide powders. Metal ions in the aqueous droplets were rapidly oxidized by the combustion of the surrounding flammable liquid. The ECM achieved a small reaction field and a short reaction period to fabricate the submicron-sized hollow ceramic particles with extremely thin wall and chemically homogeneous ceramic powder. Alumina, zirconia, zirconia-ceria solid solutions and barium titanate were synthesized by the ECM process. Alumina and zirconia powders were characterized to be metastable in crystalline phase and hollow structure. The wall thickness of alumina was about 10 nm. The zirconia-ceria powders were found to be single-phase solid solutions for a wide composition range. These powders were characterized as equiaxed-shape, submicron-sized chemically homogeneous materials. The powder formation mechanism was investigated through the synthesis of barium titanate powder with different metal sources

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...

Powder Metallurgy Reconditioning of Food and Processing Equipment Components

Science.gov (United States)

Nafikov, M. Z.; Aipov, R. S.; Konnov, A. Yu.

2017-12-01

A powder metallurgy method is developed to recondition the worn surfaces of food and processing equipment components. A combined additive is composed to minimize the powder losses in sintering. A technique is constructed to determine the powder consumption as a function of the required metallic coating thickness. A rapid method is developed to determine the porosity of the coating. The proposed technology is used to fabricate a wear-resistant defectless metallic coating with favorable residual stresses, and the adhesive strength of this coating is equal to the strength of the base metal.

Thermal conductivity model for powdered materials under vacuum based on experimental studies

Directory of Open Access Journals (Sweden)

N. Sakatani

2017-01-01

Full Text Available The thermal conductivity of powdered media is characteristically very low in vacuum, and is effectively dependent on many parameters of their constituent particles and packing structure. Understanding of the heat transfer mechanism within powder layers in vacuum and theoretical modeling of their thermal conductivity are of great importance for several scientific and engineering problems. In this paper, we report the results of systematic thermal conductivity measurements of powdered media of varied particle size, porosity, and temperature under vacuum using glass beads as a model material. Based on the obtained experimental data, we investigated the heat transfer mechanism in powdered media in detail, and constructed a new theoretical thermal conductivity model for the vacuum condition. This model enables an absolute thermal conductivity to be calculated for a powder with the input of a set of powder parameters including particle size, porosity, temperature, and compressional stress or gravity, and vice versa. Our model is expected to be a competent tool for several scientific and engineering fields of study related to powders, such as the thermal infrared observation of air-less planetary bodies, thermal evolution of planetesimals, and performance of thermal insulators and heat storage powders.

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.

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.

STUDY OF THE USE OF EDIBLE POWDERS TOMATO SAUCE TECHNOLOGIES

Directory of Open Access Journals (Sweden)

O. Benderska

2018-04-01

Full Text Available Considered the technology for the production of edible powders from vegetable raw materials. The technology for producing powders from berries is developed to produce a high-quality product in which all ingredients of raw materials are stored in a concentrated form.The current trend in nutrition is related to the expansion of the range of functional products whose daily use contributes to the prevention of hypovitaminoses and metabolic disorders, and ultimately to the rehabilitation of the population. New, non-traditional sources of local raw materials, including plant based products, need to be explored and exploited in order to address the issue of instantiate new generation of healthy foods, and the development of technologies for obtaining functionalities. The use of fruit crops, the most source of biologically active substances, is very promising in this direction.The Department of Preservation Technology of the National University Food Technology has conducted a study to enable the use of fruit and berries for food powders. To this end, powder has been obtained from the blueberry berries of ordinary, with the establishment of its physico-chemical properties.The patterns of the influence of the blueberry powder on the functional properties of the foodstuffs were investigated in the example of tomato sauces.Analysis of the results of the studies has shown that a blueberry berry powder can be used in the production of canned and other products not only to enrich their functional ingredients but also to provide them with new technological properties. The food powders received do not contain harmful impurities, have high food value, are easily absorbed by the body, compact and long periods of time. Studies have shown that the blueberry powder is a rich source of vitamins (c acid, β-carotene, tocopherol and can be used successfully in the manufacture of tomato sauces with functional properties.

Glove powder's carrying capacity for latex protein: analysis using the ASTM ELISA test.

Science.gov (United States)

Beezhold, D; Horton, K; Hickey, V; Daddona, J; Kostyal, D

2003-01-01

Glove donning powders carry latex proteins and disperse them into the workplace environment. We have used the ASTM D6499 ELISA to quantify the amount of latex antigen bound to and carried by glove powders. We could differentiate between a small amount of protein actually bound to the powders and a larger amount carried by the powder. Enhanced binding of a major allergen, Hev b 5, to the starch powders was demonstrated by Western blot. The D6499 ELISA is able to measure total latex antigen, soluble and powder bound, simultaneously without the need to centrifuge the samples.

Bulk characterization of pharmaceutical powders by low-pressure compression

DEFF Research Database (Denmark)

Sørensen, A.H.; Sonnergaard, Jørn; Hovgaard, L.

2005-01-01

Low-pressure compression of pharmaceutical powders using small amounts of sample (50 mg) was evaluated as an alternative to traditional bulk powder characterization by tapping volumetry. Material parameters were extrapolated directly from the compression data and by fitting with the Walker...

30 CFR 75.1101-15 - Construction of dry powder chemical systems.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Construction of dry powder chemical systems. 75.1101-15 Section 75.1101-15 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR...-15 Construction of dry powder chemical systems. (a) Each self-contained dry powder system shall be...

Direct visual observation of powder dynamics in RF plasma-assisted deposition

International Nuclear Information System (INIS)

Howling, A.A.; Hollenstein, C.; Paris, P.J.

1991-04-01

Contamination due to particles generated and suspended in silane rf plasmas is investigated. Powder is rendered visible by illumination of the reactor volume. This simple diagnostic for global, spatio-temporal powder dynamics is used to study particle formation, trapping and powder reduction by power modulation. (author) 4 figs., 11 refs

A parametric study pf powder holdups in a packed bed under ...

African Journals Online (AJOL)

More specifically, a parametric study is performed to determine the effects of the gas blast velocity, particle size adn powder loading on the powder holdups. Results are presented in terms of fines accumulation area. This work shows the dependency of the powder holdups on the packed bed flow parameters. Keywords: ...

Powdering of Hot-dip Galvannealed steel using Finite Element Analysis

International Nuclear Information System (INIS)

Kim, D. W.; Jang, Y. C.; Lee, Y. S.; Kim, S. I.

2007-01-01

Demand for hot-dip galvannealed steel has been increased due to it high corrosion resistance, paintability, and formability in automotive industry. Coating of Hot-dip galvannealed steel consists of various Fe-Zn intermetallic compounds. Since the coating is hard and therefore it is very brittle, the surface of steel sheet is easy to be ruptured during second manufacturing processing. This is called as powdering. Hence, various research have been carried out to prohibit powdering for improving the quality of GA steel during second manufacturing processing. This paper performed finite element analysis to evaluate local powdering and compared FEA results with V-bending test. The effects of punch radius and coating strength on the powdering was examined

Study on the sterilization of egg white powder by irradiation

International Nuclear Information System (INIS)

Fu Lixin; Meng Lifen; Zhao Xiaonan; Xu Dechun; Hu Shaoxin; Chen Changdong; Wang Zhidong

2013-01-01

The sterilizing effect, influence on main essential nutrient and sensory qualities of egg white powder treated with 60 Co γ-ray irradiation were studied. The microorganism index of egg white powder samples treated with 4 kGy irradiation could meet the government food sanitation standard, and the sterilization rate could reach 100%. The irradiation doses from 4 to 10 kGy had little influence on egg white powder protein, crude fiber and amino acidscontent, and the sensory quality such as color, luster, and scent changed little below 6 kGy irradiation. Considering the result of this study, the optimal irradiation dose for egg white powder sterilization was 4 to 6 kGy. (authors)

Simulation for the powder movement and accumulation in the lower part of blast furnace

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, Takashi [Mineral Resources Research Center, Nippon Steel Technoresearch, Futtsu-shi Chiba (Japan)

1998-12-31

The behavior of unburnt char and coke powder in the blast furnace becomes material for discussion with the increase in injection rate of pulverized coal into the blast furnace. An analysis was made as to the simulation of powder accumulation at the deadman and dripping zone of blast furnace by using a powder/gas two-phases flow experimental data. When an excessive powder has penetrated at a low gas velocity, it brings an increment in holdup and the controlling factors are powder/gas ratio and gas velocity. An empirical formula used for estimating the powder hold-up in the blast furnace internal conditions has proposed based on similarity. The controlling {pi} numbers are Floude number, powder/gas ratio and particle diameter ratio of powder/lump. This empirical formular was connected with Blast Furnace Total Model `BRIGHT` for the simulation of powder amount distribution in the lower part of blast furnace. When Powder diameter Dk exceeds 100 {mu} and gas velocity becomes lower than 0.7m/s at PC1OOkg/T, the powder tends to accumulate in the deadman. These results was available for the decision of optimum blast conditions and optimum powder diameter in the high amount of pulverized coal injection to the blast furnace. (author) 10 refs.

Simulation for the powder movement and accumulation in the lower part of blast furnace

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, Takashi [Mineral Resources Research Center, Nippon Steel Technoresearch, Futtsu-shi Chiba (Japan)

1997-12-31

The behavior of unburnt char and coke powder in the blast furnace becomes material for discussion with the increase in injection rate of pulverized coal into the blast furnace. An analysis was made as to the simulation of powder accumulation at the deadman and dripping zone of blast furnace by using a powder/gas two-phases flow experimental data. When an excessive powder has penetrated at a low gas velocity, it brings an increment in holdup and the controlling factors are powder/gas ratio and gas velocity. An empirical formula used for estimating the powder hold-up in the blast furnace internal conditions has proposed based on similarity. The controlling {pi} numbers are Floude number, powder/gas ratio and particle diameter ratio of powder/lump. This empirical formular was connected with Blast Furnace Total Model `BRIGHT` for the simulation of powder amount distribution in the lower part of blast furnace. When Powder diameter Dk exceeds 100 {mu} and gas velocity becomes lower than 0.7m/s at PC1OOkg/T, the powder tends to accumulate in the deadman. These results was available for the decision of optimum blast conditions and optimum powder diameter in the high amount of pulverized coal injection to the blast furnace. (author) 10 refs.

Peculiarities of powder brittle media compaction

International Nuclear Information System (INIS)

Perel'nam, V.E.; Aristarkhov, A.I.

1981-01-01

The paper is concerned with theoretical and practical aspects of the compaction process for powders of almost unstrained materials. Consideration from the standpoint of compressible body strain mechanics shows that such porous media may have a certain ''threshold'' density. Ductile characteristics of the porous material compacted up to this extent are identical with properties of compacrat bodies, i.e. there is a theoretically substantiated ban on a possibility of their further compaction without changing the state of the powder particle material. Theoretical conclusions are confirmed by results of experimental studies in compaction of titanium- containing ceramics [ru

Morphology study of refractory carbide powders

International Nuclear Information System (INIS)

Vavrda, J.; Blazhikova, Ya.

1982-01-01

Refractory carbides were investigated using JSM-U3 electron microscope of Joelco company at 27 KV accelerating voltage. Some photographs of each powder were taken with different enlargements to characterise the sample upon the whole. It was shown that morphological and especially topographic study of powders enables to learn their past history (way of fabrication and treatment). The presence of steps of compact particle fractures and cracks is accompanied by occurence of fine dispersion of carbides subjected to machining after facrication. On the contrary, the character of crystallographic surfaces and features of surface growth testify to the way of crystallization

Powder metallurgy - some economic considerations

Energy Technology Data Exchange (ETDEWEB)

Kassem, M.E.

1982-01-01

As a forming process powder metallurgy offers reductions in material and energy consumption. The engineering prerequisites and economics are discussed in relation to several industrial applications including automobile parts. 14 refs.

Stability of captopril in powder papers under three storage conditions

International Nuclear Information System (INIS)

Taketomo, C.K.; Chu, S.A.; Cheng, M.H.; Corpuz, R.P.

1990-01-01

The stability of captopril in powder papers under three different storage conditions was determined. Captopril 12.5-mg tablets were triturated with lactose to a final concentration of 2 mg of captopril in 100 mg of powder. A total of 240 powder papers were prepared and stored in class A prescription vials (80 papers), 002G plastic zip-lock bags (80 papers), and Moisture Proof Barrier Bags (80 papers). Immediately after preparation and at 1, 2, 3, 4, 8, 12, and 24 weeks of storage at room temperature, powder papers under each storage condition were reweighed and the contents were assayed for captopril concentration by a stability-indicating high-performance liquid chromatographic method. More than 90% of the initial captopril concentration was retained under all storage conditions during the first 12 weeks of the study. Captopril disulfide, a degradation product, was detected in one sample stored in a plastic zip-lock bag at 24 weeks. Captopril was stable for the entire 24-week period in powder papers stored in either the class A prescription vial or the Moisture Proof Barrier Bag. Captopril in powder papers is stable for at least 12 weeks when stored at room temperature under all three storage conditions

Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder.