Oscillatory magnetogasdynamic slip flow in a microchannel

The problem of pressure-driven magnetogasdynamic (MGD) slip flow with small rarefaction through a long microchannel is considered. The flow is driven by a steady or oscillatory pressure gradient. The study of MGD flows in microchannels is of interest since they occur in many electromagnetic microscale devices. In obtaining the microfluidic solutions in the presence of a magnetic field, some additional physical, mathematical, and numerical issues need to be considered. These issues deal with the scaling laws for microscale MGD flows and the relevant parameters such as Mach number, Reynolds number, Hartmann number, magnetic Reynolds number, and Knudsen number. For planar constant area microchannels, it is possible to obtain the analytical solutions for both steady and oscillatory pressure-driven flows at low magnetic Reynolds numbers. The flow field is assumed to be quasi-isothermal, which is a good assumption in the absence of a strong electric field. As physically expected, at higher values of the magnetic field (that is at a higher Hartmann number) the velocity profile in the channel flattens, and the pressure varies nonlinearly along the channel.     

Olive oil based novel thermo-reversible emulsion hydrogels for controlled delivery applications

Gels have been considered as a popular mode of delivering medicament for the treatment of sexually transmitted diseases (STDs) (e.g. human immunodeficiency virus, bacterial vaginosis, epididymitis, human papillomavirus infection and condylomata acuminata etc.). The present study discusses the development of novel olive oil based emulsion hydrogels (EHs) using sorbitan monopalmitate as the structuring agent. The developed EHs may be tried as drug delivery vehicle for the treatment of STDs. The formation of EHs was confirmed by fluorescence and confocal microscopy. FTIR studies suggested intermolecular hydrogen bonding amongst the components of the EHs. X-ray diffraction study suggested the amorphous nature of the EHs. The developed EHs have shown non-Newtonian flow behavior. The EHs were found to be biocompatible. The formulations were able to effectively deliver two model antimicrobial drugs (e.g. ciprofloxacin and metronidazole), commonly used in the treatment of the STDs.     

Ergodic capacity analysis of cooperative amplify‐and‐forward relay networks over generalized fading channels

This paper presents two new methods for evaluating the ergodic channel capacities of cooperative non‐regenerative multirelay networks in a myriad of fading environments and under three distinct source‐adaptive transmission policies: (i) optimal rate adaptation with a fixed transmit power; (ii) optimal joint power‐and‐rate adaptation; and (iii) truncated channel inversion with fixed rate. In contrast to the previous related works, our proposed unified analytical frameworks that are based on the moment generating function and/or the cumulative distribution function of end‐to‐end signal‐to‐noise ratio allow us to gain insights into how power assignment during different transmission phases, relay node placement, fade distributions, and dissimilar fading statistics across the distinct communication links impact the ergodic capacity, without imposing any restrictions on the channel fading parameters. Copyright © 2013 John Wiley & Sons, Ltd.     

Stereo-stability and temperature induced transitions of collagen mimics

Collagenous matrix proteins present in almost every part of the vertebrate organism and in many non-vertebrates are expressed in a rich structural variety. The present communication attributes the theoretical interpretation of temperature induced transitions in collagen mimics in terms of stereochemistry, as explained by the modified Zimm and Bragg model. The results are found to be in good agreement with the experimental data as reported independently by Steven K. Holmgren, Jonthan A. Hodges and Cara L. Jenkins. The order of the values of nucleation parameter and enthalpy changes obtained theoretically, is attributed not only to the stereo-chemistry but also to the relative increase in the degree of stability of collagen mimics.     

Release of dithiocarbamates into artificial sweat from latex vulcanizates: Effects of the accelerator type and storage time

The release of commonly used dithiocarbamate accelerators, namely, zinc diethyldithiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), zinc dibenzyldithiocarbamate, zinc isobutyldithiocarbamate, and zinc diisononyldithiocarbamate, into artificial sweat from natural rubber latex vulcanizates was studied. The extent of release of ZDEC was much higher than that of ZDBC or other higher homologues, as indicated by high‐performance liquid chromatography analysis. The effect of the storage time on the extent of release of ZDEC into artificial sweat from vulcanizates prepared with various amounts of ZDEC was studied. The result showed that ZDEC migrated significantly to the surface of the vulcanizates upon storage, and the amount that migrated increased with an increase in the shelf time. Moreover, the amount of ZDEC that migrated increased with an increase in the amount of ZDEC added to the latex formulations. The rate of migration, as determined from the slopes of the migration curves, was dependent on the residual ZDEC content, which in turn depended on the initial level of ZDEC incorporated during latex compounding. The analysis of the migration data showed that the migration followed a Fickian behavior, and the diffusion coefficient of ZDEC was slightly dependent on the concentration. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2055–2061, 2006     

The performance evaluation of a continuous vegetable cooker

Summary A continuous vegetable cooker was evaluated and shown to produce improved quality-cooked vegetables under more hygienic conditions as compared to batch type conventional cooking. The operating parameters for 85  ±  3% degree of cooking as optimal were determined for green peas, carrot, kohlrabi, and radish. The final product was evaluated in comparison to conventional cooking in terms of the degree of cooking and product quality (retention of chlorophyll, vitamin C and carotenoids; microbial analysis). The thermal efficiency of the cooker and specific energy consumption were compared with published data for steam blanchers.