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Belén Levenfeld - One of the best experts on this subject based on the ideXlab platform.
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influence of Powder Particle size distribution on rheological properties of 316 l Powder injection moulding feedstocks
2010Co-Authors: Maria Eugenia Sotomayor, Alejandro Várez, Belén LevenfeldAbstract:Abstract The rheological behaviour of highly filled polymer systems used in Powder injection moulding (PIM) technology influences strongly the final properties of the products. The study of the influence of Particle size distribution on the rheological properties of 316 L stainless steel feedstocks is presented. Two kinds of gas-atomized Powders were employed with d90 of 8 and 26 μm of Particle size. Five feedstocks were prepared at Powder loadings of 50, 55, 60 and 65 vol.%, employing both starting Powders and their own mixtures in volume ratios 25/75, 50/50 and 75/25. The binder was composed by 50 vol.% of high density polyethylene and 50 vol.% of paraffin wax. Feedstocks were prepared in a torque rheometer with a pair of roller rotor blades and rheological measurements were performed in a capillary rheometer. The effects of the Powder loading and different Particle size distributions on the rheological properties of feedstocks were investigated. Different rheological parameters, like melt viscosity, power flow index and activation energy were determined. A relationship between Powder characteristics and rheological behaviour was established.
I Goni - One of the best experts on this subject based on the ideXlab platform.
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influence of Powder Particle size distribution on complex viscosity and other properties of acrylic bone cement for vertebroplasty and kyphoplasty
2006Co-Authors: Lidia Hernandez, M Gurruchaga, I GoniAbstract:For use in vertebroplasty and kyphoplasty, an acrylic bone cement should possess many characteristics, such as high radiopacity, low and constant viscosity during its application, low value of the maximum temperature reached during the polymerization process (Tmax), a setting time (tset) that is neither too low nor too high, and high compressive strength. The objective of this study was to investigate the influence of the Powder Particle distribution on various properties of one acrylic bone cement; namely, residual monomer content, Tmax, tset, complex viscosity, storage and loss moduli, injectability, and quasi-static compressive strength and modulus. It was found that the formulations that possessed the most suitable complex viscosity-versus-mixing time characteristics are those in which the ratio of the large poly(methyl methacrylate) beads (of mean diameter 118.4 μm) to the small ones (of mean diameter 69.7 μm) was at least 90% w/w. For these formulations, the values of the other properties determined were acceptable. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
James R. Neale - One of the best experts on this subject based on the ideXlab platform.
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Analysis of skim milk Powder deposition on stainless steel tubes in cross-flow
2015Co-Authors: Timothy Gordon Walmsley, Michael R.w. Walmsley, Martin John Atkins, James R. NealeAbstract:Abstract Particulate fouling on the gas side of heat recovery equipment is a common industrial problem. The aim of this study is to characterize the deposition of skim milk Powder on a single bare tube in cross-flow. A custom built rig is applied to simulate exhaust air conditions that is experienced in an exhaust exchanger. For a constant airflow rate, increasing Particle stickiness resulted in greater deposition coverage around the front of the round and elliptical tubes peaking in the middle, whereas the turned square tube tended to be either clear or covered. Results show that the skim milk Powder Particle impact angle on the tube, as opposed to the wall shear stress, is an important determinant for deposition. During each test and at the conclusion of each test, which was when fouling reached an asymptote, the amount of deposition coverage and build-up on the tube varied depending on the tube shape, Particle stickiness, and air velocity.
Peter Apata Olubambi - One of the best experts on this subject based on the ideXlab platform.
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effect of starting Powder Particle size and heating rate on spark plasma sintering of fe ni alloys
2016Co-Authors: M B Shongwe, M M Ramakokovhu, S Diouf, M O Durowoju, Babatunde Abiodun Obadele, R Sule, Moipone Linda Lethabane, Peter Apata OlubambiAbstract:Abstract The effect of starting Powder Particle size and heating rate on spark plasma sintering of Fe Ni alloys was investigated, with the Particle Powder size varying from 3 to 70 μm and heating rate from 50 to 150 °C/min. The effect of the starting Powder Particle size was more obvious when comparing 3-FeNi and 70-FeNi at all heating rates, with the former having better density and hardness than the latter. Sintered densities close to theoretical (≥99%) were achieved for a heating rate of 50 °C/min for the different starting Particle size Powders, and decreased with increasing heating rate. The average grain size of alloys sintered at 150 °C/min was ∼34% smaller than those sintered at 50 °C/min. The porosity content of the sintered samples increased with increasing heating for the same Particle size. The shrinkage rate depends on both heating rate and Particle size. At a Particle size of 3 μm and a heating rate of 50 °C/min, three peaks were observed indicative of the phenomena responsible for good densification. As the heating rate increases, only two peaks and one peak are observed at heating rates of 100 and 150 °C/min, respectively. This suggests that, unlike high heating rates, the longer processing time at low heating rate allows the three phenomena to take place. The hardness measurement revealed a steady decrease with increasing heating rate. At a heating rate of 150 °C/min the Particles were well packed but no typical dimple structure of a ductile material was observed. However, for samples sintered at 50 and 100 °C/min a typical dimple fracture morphology was observed.
Maria Eugenia Sotomayor - One of the best experts on this subject based on the ideXlab platform.
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influence of Powder Particle size distribution on rheological properties of 316 l Powder injection moulding feedstocks
2010Co-Authors: Maria Eugenia Sotomayor, Alejandro Várez, Belén LevenfeldAbstract:Abstract The rheological behaviour of highly filled polymer systems used in Powder injection moulding (PIM) technology influences strongly the final properties of the products. The study of the influence of Particle size distribution on the rheological properties of 316 L stainless steel feedstocks is presented. Two kinds of gas-atomized Powders were employed with d90 of 8 and 26 μm of Particle size. Five feedstocks were prepared at Powder loadings of 50, 55, 60 and 65 vol.%, employing both starting Powders and their own mixtures in volume ratios 25/75, 50/50 and 75/25. The binder was composed by 50 vol.% of high density polyethylene and 50 vol.% of paraffin wax. Feedstocks were prepared in a torque rheometer with a pair of roller rotor blades and rheological measurements were performed in a capillary rheometer. The effects of the Powder loading and different Particle size distributions on the rheological properties of feedstocks were investigated. Different rheological parameters, like melt viscosity, power flow index and activation energy were determined. A relationship between Powder characteristics and rheological behaviour was established.