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Mixed Powder (mixed + powder)

Distribution by Scientific Domains
Physics and Astronomy40%

Selected Abstracts

Improvement of the agitation granulation method to prepare granules containing a high content of a very hygroscopic drug

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 11 2006
Nobuaki Hirai
This study describes a new approach to the preparation of a granulate with a high content of a very hygroscopic powder or drug, using the agitation granulation method, and the development of a tablet formulation using these granulates. A Chinese medicine extract, Hatimi-zio-gan, was used as the model of a very hygroscopic drug. Among the several excipients tested, only porous calcium silicate could be used to prepare granules, with a mixing ratio (extract to porous calcium silicate) from 2:1 to 20:1. With other excipients, very large lumps were formed during the granulation process. The best mixing ratio of extract to porous calcium silicate was 6:1. For preparation of the granules, water could be added to the mixed powder within a range of 1- to 4-times the amount of porous calcium silicate. From these results, it was concluded that the ability of porous calcium silicate to hold large amounts of water in its numerous pores may allow for the preparation of granulates with a high content of very hygroscopic drugs. Starch with partial ,-links, carboxymethyl starch sodium salt and crospovidone were used for selection of the disintegration agent. When crospovidone was used as a disintegration agent, tablets containing about 70% of the Chinese medicine extract disintegrated in less than 7 min, with good dissolution rates. The same process was applied to extracts of Hotyu-ekki-to, Syo-seiryu-to, Boi-ogi-to and Bohu-tusyo-san. The absorption of paeoniflorin, a characteristic monoterpene glucoside contained in Hatimi-zio-gan extract, was evaluated in beagle dogs after oral administration of the Hatimi-zio-gan tablets prepared in this study. The values of Cmax and AUC obtained after administration of the tablets prepared in this study were significantly greater than those obtained for commercial tablets. [source]

Local structure and magnetic properties of mechanically alloyed Fe60Mn40

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008
Dong-Seok Yang
Abstract Fe60Mn40 alloys were fabricated by mechanical alloying process for 1 h, 4 h, 6 h, 12 h and 24 h, respectively. The structural evolution during the milling process has been investigated by X-ray diffraction and extended X-ray absorption fine structure (EXAFS). The structural investigation shows that the alloying was activated in 6 h and progressed significantly in 24 h. Also, it showed that the BCC characteristics of the mixed powder remained after 6 h milling but disappeared after 12 h milling. It has been shown that variations of magnetic properties were closely related to the local structural evolution. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Effect of temperature on hygroscopic thickness swelling rate of composites from lignocellolusic fillers and HDPE

POLYMER COMPOSITES, Issue 11 2009
Abdollah Najafi
Effect of temperature on hygroscopic thickness swelling rate of lignocellolusic fillers/HDPE (high density polyethylene) composites was investigated. The composites were manufactured using a dry blend/hot press method. In this method, powder of plastic and dried powder of lignocellolusic material were mixed in high-speed mixer and then the mixed powder were pressed at 190°C. Lignocellolusic fillers/HDPE composites panels were made from virgin and recycled HDPE (as plastic) and wood sawdust and flour of rice hull (as filler) at 60% by weight filler loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Thickness swelling rate of manufactured wood plastic composites (WPCs) were evaluated by immersing them in water at 20, 40, and 60°C for reaching a certain value where no more thickness was swelled. A swelling model developed by Shi and Gardner [Compos. A, 37, 1276 (2006)] was used to study the thickness swelling process of WPCs, from which the parameter, swelling rate parameter, can be used to quantify the swelling rate. The results indicated that temperature has a significant effect on the swelling rate. The swelling rate increased as the temperature increased. The swelling model provided a good predictor of the hygroscopic swelling process of WPCs immersed in water at various temperatures. From the activation energy values calculated from the Arrhenius plots, the temperature had less effect on the thickness swelling rate for the composites including wood sawdust compared with the rice hull as filler and the composites including recycled compared with the virgin HDPE as plastic. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]

Production and Properties of Spray-dried Amaranthus Betacyanin Pigments

JOURNAL OF FOOD SCIENCE, Issue 7 2000
Y.Z. Cai
ABSTRACT: Amaranthus betacyanin extracts were spray-dried using a range of maltodextrins [10-25 dextrose equivalent (DE)] and starches (native/modified) as carrier and coating agents at 5 inlet/outlet air temperatures and 4 feed solid contents. Higher inlet/outlet air temperatures caused greater betacyanin loss during spray drying, and affected slightly the pigment stability during storage. Adding maltodextrins and starches significantly reduced the hygroscopicity of the betacyanin extracts and enhanced storage stability. The 25 DE/10 DE mixed powders provided a longer predicted half-life (63.6 wk) compared to the 25 DE and the 10 DE powders separately. The best dried pigment-containing powder made was superior to commercial red beet powder in physical properties. [source]

Polycrystalline sputtered Cd(Zn, Mn)Te films for top cells in PV tandem structures

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 4 2004
Sung Hyun Lee
Abstract The CdTe-ZnTe or CdTe,MnTe alloy system is evaluated for application in high efficiency polycrystalline thin film multijunction solar cells. CdZnTe alloy films with 1.6 and 1.7 eV band gap and CdMnTe with 1.6 and 1.8 eV were deposited by RF magnetron sputtering from targets made of mixed powders of CdTe and ZnTe (25% and 40%) or MnTe (13% and 25%), respectively. Without postdeposition treatment, however, both of these alloy films exhibit quite low photovoltaic performance when used to make cells with CdS as the heterojunction partner. Therefore, we have searched for an appropriate postdeposition treatment to improve the efficiency of these alloy films. As-grown films have been postdeposition treated with vapors of chlorine-containing materials such as HCl gas, CdCl2, ZnCl2 or MnCl2 in dry air or H2+Ar atmosphere. When the CdCl2 + ZnCl2 or MnCl2 vapor was used, the ratio of CdCl2 to ZnCl2 or MnCl2 was adjusted to match the stoichiometry of alloy films. The temperature of the treatment was chosen to represent conditions employed for those alloy films/CdS structures. As a result, the postdeposition treated CdZnTe and CdMnTe cell efficiency can be improved by a factor of over 100. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]