Flow and temperature patterns in an inductively coupled plasma reactor: Experimental measurements and CFD simulations

Measurements of temperature patterns in an inductively coupled plasma (ICP) have been carried out experimentally. Plasma torch was operated at different RF powers in the range of 3–14 kW at near atmospheric pressure and over a wide range of sheath gas flow rate (3–25 lpm). Measurements were made at five different axial positions in ICP torch. The chordal intensities were converted into a radial intensity profile by Abel Inversion technique. Typical radial temperature profile shows an off‐axis temperature peak, which shifts toward the wall as the power increases. Temperatures in the range of 6000–14,000 K were recorded by this method. The temperature profiles in the plasma reactor were simulated using computational fluid dynamics (CFD). A good agreement was found between the CFD predictions of the flow and temperature pattern with those published in the literature as well as the temperature profiles measured in the present work. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3647–3664, 2014     

Mechanistic origins of multi-scale reinforcements in segmented polyurethane-clay nanocomposites

The objective of the present work is to get insights into the mechanistic origin of the reinforcement effects of nanoclay on a segmented polybutadiene polyurethane-urea system. To this end, a convergent analysis of the hard domain morphology and conformational state of soft segment in the nanocomposites was carried out by using a combination of complementary characterization techniques, namely, Fourier transform infrared spectroscopy, small angle neutron scattering, transmission electron microscopy, modulated differential scanning calorimetry and dynamic mechanical analysis. Analysis of small angle neutron scattering data by a combination of Percus–Yevick hard sphere and Zernike-Ornstein model coupled with direct visualization of the dispersed hard domain morphology from transmission electron microscopy provided insight on clay induced changes in the hard domain morphology. A monotonic decrease in the domain size as well as the average interdomain distance was observed with increasing nanoclay content in the polymer matrix. Analysis of the carbonyl stretching region from FTIR showed increased degree of hydrogen bonding for the urethane carbonyl groups of the nanocomposites compared to the neat matrix. A combination of calorimetric and dynamic mechanical analysis revealed the existence of a constrained amorphous region; quantified to be ≈ 16% at the highest clay content experimented. The manifestation of these morphological and conformational changes on the nano-, micro- and macro scale reinforcements in the nanocomposites was investigated by mechanical properties at these length scales using nanoindentation, DMA and tensile testing, respectively.     

Drug‐loaded polyurethane/clay nanocomposite nanofibers for topical drug‐delivery application

In this study, polyurethane/nanoclay nanocomposite nanofibrous webs were prepared by electrospinning. An antiseptic drug, chlorhexidine acetate (CA), was loaded onto montmorillonite clay and was then incorporated into polyurethane nanofibers. For comparison, the CA drug was loaded directly into the polyurethane solution dope used to electrospin the nanofibers. The emphasis was on investigating the effect of the drug loading into the nanoclay vis‐à‐vis direct drug loading on the drug‐release behavior of nanofibrous webs. The nanofibrous webs were also evaluated for other properties, such as moisture vapor transmission, porosity determination, contact angle measurement, and antibacterial activity, which are important for topical drug‐delivery application. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40230.     

Effects of extracts of spices on rumen methanogenesis,enzyme activities and fermentation of feeds in vitro

BACKGROUND: An experiment was conducted to study the effects of boiling water, methanol and ethanol extracts (0, 0.25 and 0.50 mL) of seeds of Foeniculum vulgare (fennel), flower buds of Syzygium aromaticum (clove), bulbs of Allium sativum (garlic), bulbs of Allium cepa (onion) and roots of Zingiber officinalis (ginger) on rumen methanogenesis, fibrolytic enzyme activities and fermentation characteristics in vitro. RESULTS: Ethanol and methanol extracts of fennel, clove and garlic at 0.50 mL and clove at 0.25 mL inhibited (P < 0.05) methane production. Carboxymethylcellulase activity was reduced (P < 0.05) by ethanol and methanol extracts (0.50 mL) of fennel and clove (0.25 and 0.50 mL). The extracts of clove reduced (0.25 and 0.50 mL) xylanase and acetylesterase activities, and the fennel extract (0.50 mL) reduced (P < 0.05) xylanase activity. However, the extracts of garlic (0.50 mL) increased (P < 0.05) acetylesterase activity. Concentrations of volatile fatty acids were reduced (P < 0.05) by the extracts of garlic and onion. The extracts of garlic caused a decrease (P < 0.05) in acetate:propionate ratio (A:P) at 0.50 mL, whereas A:P was increased (P < 0.05) by the inclusion of 0.50 mL extracts of clove. Methanol and ethanol extracts of clove decreased (P < 0.05) in vitro organic matter degradability. Extracts (0.50 mL) of clove decreased (P < 0.05) the numbers of total protozoa, small entodiniomorphs and holotrichs, whereas extracts of onion, ginger and garlic enhanced (P < 0.05) protozoal numbers (both entodiniomorphs and holotrichs). CONCLUSION: Ethanol and methanol extracts of fennel and garlic have potential to inhibit rumen methanogenesis without adversely affecting rumen fermentation. Copyright © 2009 Society of Chemical Industry     

Postnatal development and testosterone dependence of a rat epididymal protein identified by neonatal tolerization

A rat epididymal protein of 27 kDa was identified using neonatal tolerization. This study reports the production and characterization of a polyclonal antiserum to this protein. ELISA was used to demonstrate that this antiserum reacts strongly with epididymal sperm proteins, but has little or no reactivity with testicular proteins. Western blot analysis revealed that this polyclonal antiserum recognized a 27 kDa protein extracted from the corpus epididymidis as well as from spermatozoa from the corpus and cauda epididymides, and immunostaining revealed the presence of the protein in the corpus to cauda epididymides. Stronger reactivity was observed in the supranuclear region and stereocilla of principal cells of the corpus epididymidis and in the luminal content of the corpus and cauda epididymides. The testicular section showed no reactivity. Treatment with the antiserum resulted in time- and dose-dependent agglutination of rat spermatozoa. By indirect immunofluorescence, the antiserum localized proteins in the mid-piece region of rat spermatozoa. Studies were carried out to determine the age at which the protein first became apparent during postnatal development. The protein was expressed from day 40 onwards, as demonstrated by western blot analysis. The androgen regulation of this protein was ascertained by castration and supplementation studies. Expression of this protein showed a decline starting at day 14 after castration and by day 21 the protein was absent; however, androgen replacement resulted in the reappearance of the protein. The results of these studies indicate that the protein identified is specific to the epididymis, and is regulated by development and androgens. The importance of epididymis-specific proteins that are regulated by androgens in sperm maturation is discussed, and the need to ascertain the sequence of the protein and clone the cognate gene is indicated.     

Pesticides removal performance by low‐pressure reverse osmosis membranes

Pressure driven techniques (viz. reverse osmosis and nanofiltration) have the potentiality to remove the pesticides from water. The observations revealed that pesticides removal mostly depends upon the molecular weight (size exclusion) and hydrophobicity (log P) of the pesticides. Interfacial polymerization of m‐phenylene diamine (MPD) and trimesoyl chloride (TMC) on the polysulfone membranes impart the salt rejection property in it. It is shown that with the greater salt rejection property, the performance removal of pesticides also is in increasing trend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3575–3579, 2006     

Wavelength dependent laser-induced etching of Cr-O doped GaAs: Morphology studies by SEM and AFM

The laser induced etching of semi-insulating GaAs 〈100〉 is carried out to create porous structure under super- and sub-bandgap photon illumination (h v). The etching mechanism is different for these separate illuminations where defect states play the key role in making distinction between these two processes. Separate models are proposed for both the cases to explain the etching efficiency. It is observed that under sub-bandgap photon illumination the etching process starts vigorously through the mediation of intermediate defect states. The defect states initiate the pits formation and subsequently pore propagation occurs due to asymmetric electric field in the pore. Formation of GaAs nanostructures is observed using scanning electron (SEM) and atomic force microscopy (AFM).