Effect of sintering temperature on the properties of Cu-Co ferrites prepared by oxalate precipitation method

Polycrystalline Cu-Co ferrite powder was synthesized following oxalate precipitation method. The samples of the compound Cu_0.5Co_0.5Fe₂O₄ were heated at different temperatures in the range of 773-1173 K and were characterized by X-ray diffraction and SEM techniques. The results of XRD show the formation of single-phase cubic spinel structure. The lattice parameter showed a minimum value for the sample heated at 1073 K. It has been observed that grain size increases with the increase in temperature and is maximum (3.2 μm) for the powder sintered at 1173 K.     

Investigations on Factors Affecting Chitosan for Dissolution Enhancement of Oxcarbazepine by Spray Dried Microcrystal Formulation With an Experimental Design Approach

In the present work effect of chitosan on microcrystal formulation for dissolution enhancement of oxcarbazepine using controlled crystallization technique coupled with spray drying was explored. The work was extended for exploration of simplified approach for stable particle size reduction. The study was performed with an experimental design approach i. e. a fractional factorial design of resolution 5 (with all 2 factor interaction) for the screening of predefined independent variables drug concentration, chitosan concentration, feed rate, inlet temperature and percent aspiration for spray drying. Whereas percent drug dissolved, wettability time, flowability in terms of angle of repose and particle size were designated as response variables. Resultant models were analyzed using multiple linear regression analysis, which generated equation to plot response surface curves along with desirability function. Results showed that chitosan concentration had significant effect on dissolution enhancement of oxcarbazepine at a level of 2% w/v. Increase in drug concentration showed decreased dissolution rate however on particle size it did not show statistically significant effect. Topographical characterization was carried out by SEM which showed that feed rate, percent aspiration and inlet temperature had significant effect on particle morphology. For deriving optimized formulation results were analyzed using desirability function for the maximum percent drug dissolved and least drug polymer matrix particle size. DSC studies showed that drug was molecularly associated with chitosan matrix or particles.     

Investigations on factors affecting chitosan for dissolution enhancement of oxcarbazepine by spray dried microcrystal formulation with an experimental design approach

In the present work effect of chitosan on microcrystal formulation for dissolution enhancement of oxcarbazepine using controlled crystallization technique coupled with spray drying was explored. The work was extended for exploration of simplified approach for stable particle size reduction. The study was performed with an experimental design approach i. e. a fractional factorial design of resolution 5 (with all 2 factor interaction) for the screening of predefined independent variables drug concentration, chitosan concentration, feed rate, inlet temperature and percent aspiration for spray drying. Whereas percent drug dissolved, wettability time, flowability in terms of angle of repose and particle size were designated as response variables. Resultant models were analyzed using multiple linear regression analysis, which generated equation to plot response surface curves along with desirability function. Results showed that chitosan concentration had significant effect on dissolution enhancement of oxcarbazepine at a level of 2% w/v. Increase in drug concentration showed decreased dissolution rate however on particle size it did not show statistically significant effect. Topographical characterization was carried out by SEM which showed that feed rate, percent aspiration and inlet temperature had significant effect on particle morphology. For deriving optimized formulation results were analyzed using desirability function for the maximum percent drug dissolved and least drug polymer matrix particle size. DSC studies showed that drug was molecularly associated with chitosan matrix or particles.     

Gaseous chlorine dioxide inactivation of microbial contamination on whole black peppercorns

Black peppercorn is a common ingredient imported and used in uncooked or ready-to-eat foods in the United States. They might be exposed to fecal coliforms and other microbial contamination due to a lack of good agricultural and manufacturing practices in some developing countries under which they were grown and harvested, thus causing economic losses to the peppercorn industry in the United States. We investigated the effect of gaseous chlorine dioxide (ClO₂) on reducing the microbial population levels of coliforms, aerobic bacteria, yeasts, and molds on unprocessed black peppercorns. Treatments on peppercorns were conducted in a 30-L airtight chamber, and equal amounts of dry media precursors were used to generate gaseous ClO₂. Whole peppercorns (200 g) were exposed to 20, 30, and 40 g of precursor dose for up to 60 min at 21 ± 0.4°C and in combination with mild heat at 40 ± 2°C. Aerobic bacteria, coliforms, yeasts, and molds on peppercorns were enumerated before (7.4, 7.2, and 7.1 log CFU/g, respectively) and after treatments. Results after treatment demonstrated 0.8–1 log₁₀ (90%) reduction for all the microbes post-treatment at 21 ± 0.4°C. The treatments conducted with a 30 g precursor dose for 60 min at 21 ± 0.4°C reduced statistically higher (p < .05) microorganisms than those at 40 ± 2°C. Our work demonstrated that gaseous ClO₂ could be used as a part of an overall hurdle technology to reduce the coliforms, aerobes, yeasts, and molds on black peppercorns without affecting the visual quality.     

Carbon black distribution driven by its concentration and its effect on physico-mechanical properties of styrene butadiene rubber and butadiene rubber miscible rubber blends

This paper discusses the influence of partitioning of carbon black (CB) with its increasing concentration (i.e., 10, 20, 30, 40, and 50 phr) on physical and static mechanical properties of Styrene Butadiene Rubber (SBR)/Butadiene Rubber (BR) rubber–rubber blends (RRB's) in 70SBR:30BR blend ratio. Partitioning of CB towards BR in CB-filled SBR/BR RRB's is quantitatively determined via dynamic mechanical analysis (DMA). DMA confirmed increased partitioning of CB towards BR phase with increasing CB. DMA data on the partitioning of CB towards BR were in good agreement with nuclear magnetic spectra obtained by solid-state nuclear magnetic resonance spectroscopy (SS-NMR spectroscopy). Curing properties, relative density, hardness, tensile test, tear test, and transmission electron microscopy (TEM) on CB filled SBR/BR RRB's were carried out to determine the effect of increasing concentration of CB on physical, mechanical, and dispersion characteristics in comparison to neat SBR/BR RRB's.