Optical and electrical characterization of conducting polymer-single walled carbon nanotube composite films

The optical and electrical properties of the conducting polymer poly(3-hexylthiophene) and single walled carbon nanotube (SWCNT) composites have been investigated. The composites were prepared by dispersing carbon nanotubes in the polymer matrix already dissolved in 1,2-dichlorobenzene. The optical absorption, photoluminescence (PL) and electrical conductivity of the composite was studied as a function of SWCNT concentration in the solution. The absorption coefficient of the polymer was found to be unaffected upto a SWCNT concentration 5% w/w. However a minor decrease in the absorption in visible region was observed for higher SWCNT concentrations. The intensity of PL emission from the composite was measured and was found to decrease with the increase in SWCNT concentration. For a SWCNT concentration of 30% w/w, ∼90% of the PL was quenched, indicating an ultra fast transfer of photoinduced charges from donor polymer to acceptor SWCNT. Direct current conductivity of the composite film was found to increase rapidly with the increase in SWCNT concentration and an increase of ∼5 orders of magnitude was observed for a 30% w/w concentration. The enhancement in conductivity is explained in terms of percolation theory with an estimated percolation threshold of 2% w/w.     

Studies on Hot Corrosion of the Microstructurally Different Regions of 2.25Cr-1Mo (T22) Boiler Tube Steel Weldment

This study examines the effect of microstructurally different regions on the hot corrosion of tungsten inert gas weldment in 2.25Cr-1Mo (T22) boiler tube steel. Various regions of weldment were oxidized in molten salt Na₂SO₄-60% V₂O₅ environment at 900 °C. The base metal was found to oxidize at much higher rates than the weld metal and the heat-affected zone. Oxide scales formed in the three regions were compared by scanning electron microscopy with energy dispersive of X-ray analysis, X-ray diffraction pattern, and electron probe microanalysis. The research investigates the formation of inner scales with free Cr over the HAZ.     

Optimisation of Detergent Ingredients for Stain Removal Using Statistical Modelling

Artificially soiled test fabrics are widely used to study the cleaning performance of detergents formulations. In this study, artificial soiled cotton test fabrics were prepared in the laboratory using carbon black as a model soil. Design of experiments was used to optimise the concentration of detergent ingredients for stain removal. A multi‐factorial analysis of variance was used to model the effect of sodium dodecylbenzene sulfonate, nonylphenol ethoxylate, sodium silicate, sodium citrate and sodium carbonate as builders on soil removal. A colourimetric evaluation using the CIELAB system was used to measure soil removal. In general, performance increases with increasing concentration of surfactant, silicate and soda ash.     

Nitrophenoxy groups containing polybenzimidazoles as polymer electrolytes for fuel cells: Synthesis and characterization

Polybenzimidazoles containing different contents of pendant nitrophenoxy groups were prepared by condensation of 3,3′‐diamino‐benzidine with a mixture of 3,5‐dicarboxyl‐4′‐nitro diphenyl ether and isophthalic acid (IPA) in different ratios in polyphosphoric acid. The polymers are soluble in polar aprotic solvents, they have inherent viscosities in the range of 0.75–1.10 dL g^?1 and they form tough and transparent films on solution casting. They have good thermal stability with initial decomposition temperature ranging from 380 to 416°C in nitrogen, good tensile strength ranging from 56 to 65 MPa and reasonably good oxidative stability. Phosphoric acid uptake of these polymers is low compared with PBI and membranes doped with phosphoric acid exhibit good proton conductivity in the range of 6.6× 10^?3 to 1.9× 10^?2 S/cm at 25°C and 1.2× 10^?2 to 4.9× 10^?2 S/cm at 175°C, compared with 3.9× 10^?3 S/cm at 25°C and 3.2× 10^?2 S/cm at 175°C for PBI. These membranes are suitable for applications as polymer electrolyte for fuel cell and presumably for gas separation at high temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Comparison of alginate and pectin based beads for production of poultry probiotic cells

A comparative study on the stability and potential of alginate and pectin based beads for production of poultry probiotic cells using MRS medium in repeated batch fermentation was conducted. The bead cores, made of three types of materials, i.e., ca-alginate, ca-pectinate and ca-alginate/pectinate, were compared. The effect of single and double layer coatings using chitosan and core material, respectively, on the bead stability and cell production were also studied. The pectin based beads were found to be more stable than that of the alginate beads and their stability was further improved by coating with chitosan. The cell concentration in pectin based beads was comparable to that in the alginate beads. On the other hand, pectin based beads gave significantly lower cell concentration in the growth medium for the initial fermentation cycles when compared to the alginate beads. In conclusion, pectin was found to be potential encapsulation material for probiotic cell production owing to its stability and favourable microenvironment for cell growth.     

Velocity slip,chemical reaction,and suction/injection effects on two-dimensional unsteady MHD mass transfer flow over a stretching surface in the presence of thermal radiation and viscous dissipation

The purpose of this study is to analyze the impact of velocity slip, chemical reaction, and suction/injection on two-dimensional mass transfer effects on unsteady MHD flow over a stretching surface in the presence of thermal radiation and viscous dissipation. The governing time-dependent nonlinear partial differential equations are transformed into nonlinear ordinary differential equations by using similarity transformations. The converted equations are solved using the numerical technique with the help of Keller-Box method. The effect of nondimensional variables is studied and graphically illustrated on velocity, temperature, concentration, friction factor, Nusselt number, and Sherwood number. Concentration and temperature profiles are enhanced and the contrasting pattern for velocity profiles as increasing the velocity slip and magnetic parameter. The concentration profile is diminished as the Schmidt number (Sc) and chemical reaction (C_r) increase. The concentration, velocity, and temperature profiles display a reversal pattern, as the suction and unsteady parameter (A) increase. The findings of this study are very well-acknowledged with current research.     

Incineration of diesel particulate matter using induction heating technique

Incineration of diesel particulate matter for the regeneration of a mesh-type particulate-filter is achieved using induction heating technique. Heating of the diesel particulates deposited on the mesh-type particulate-filter at around 600 °C is investigated. In the case of the particulate filter, stainless-steel mesh-type filters are considered and the influence on filtering efficiency, the engine performance due to back-pressure generation is studied. Theoretical estimation shows that induction heating approach for the regeneration via exhaust gas heating requires high power (>3 kW). On the other hand, regeneration of mesh-type particulate-filter using induction heating technique requires a low input power of around 0.5 kW in the off-line condition. The proposed mesh-type particulate-filter allowed a filtration efficiency of around 30–40% at lower engine speeds and part loads. Particulate combustion through induction heating at static condition is studied and power required for mesh-type filter and sintered metal filter regeneration during engine operation is estimated theoretically.     

Effect of orally administered phenethyl isothiocyanate on hepatic gene expression in rats

Scope: Phenethyl isothiocyanate (PEITC) is a constituent of cruciferous vegetables that has demonstrated cancer preventive activity in a number of cancer models including lung, prostate, and breast cancer. Our objective was to examine the effects of the oral administration of PEITC for 7 days on the hepatic expression of genes important in drug metabolism and toxicity in Sprague Dawley rats. The liver is the major site for the metabolism of various xenobiotics and carcinogens, and determining the effects of PEITC on the gene expression of hepatic enzymes may provide insight into mechanisms underlying the cancer preventive activity of PEITC. Methods and results: Using a microarray containing 282 genes, we observed that PEITC significantly up‐regulated UDP‐glucuronosyltransferase UGT1A6 and strongly down‐regulated nicotinamide N‐methyltransferase (NNMT). We also confirmed the down‐regulation of NNMT by real‐time quantitative RT‐PCR. Other genes that were significantly up‐regulated were the drug metabolizing enzyme cyp2b15, the anti‐apoptotic gene bcl2l2, and the stress regulators Gadd45b, Dnajb9, Dnajb5 and Hspb1. Conclusion: Our results indicate new targets that may be important in the mechanisms of the anticancer effects of PEITC. Of particular significance was the down‐regulation of NNMT which may represent a new target for the treatment of a variety of cancers.     

The steady-state kinetics of parallel reaction networks

The conventional kinetic analysis of an overall reaction (OR) is limited to a single sequential pathway of molecular steps at a time, based either on the general quasi-steady state (QSS) approach of Bodenstein, or on the much simpler but limited Langmuir–Hinshelwood–Hougen–Watson (LHHW) approach based on assuming a single rate-determining step (RDS), the remaining being quasi-equilibrated (QE). We recently described a new algebraic methodology for deriving the QSS rate expression for a reaction sequence, which allowed interpretation of the final result in an Ohm's law form, i.e., OR rate=OR motive force/OR resistance of an equivalent electric circuit, where the consecutive mechanistic steps represent resistors in series. Here, we propose a similar Ohm's law form of QSS rate for a reaction system involving parallel pathways, whose equivalent electrical circuit derives directly from the reaction route (RR) Graph of its mechanism, as proposed earlier by us. The results are exact for a reaction network with mechanistic steps linear in intermediates concentrations, while they are approximate, albeit accurate, for non-linear step kinetics. We further show how the LHHW methodology, combined with the concept of intermediate reaction might be utilized to obtain the step resistances involved. For illustration, we utilize the relatively simple examples of: (1) the gas-phase hydrogen–bromine non-catalytic reaction (non-linear kinetics), and (2) zeolite catalyzed N₂O decomposition reaction (linear kinetics). However, the approach is useful for more complex non-catalytic, catalytic and enzymatic reactions networks as well.     

Life cycle assessment of biodiesel production using alkali, soluble and immobilized enzyme catalyst processes

This study deals with the Life Cycle Assessment (LCA) of three different catalytic processes for biodiesel production. In the LCA study, a “cradle to gate” approach was adopted to estimate the environmental impact of different catalytic processes such as immobilized, soluble biocatalyst and alkali catalyst. The results revealed that, biodiesel production using immobilized biocatalyst has less environmental impact compared to alkali and soluble biocatalyst. The environmental impact of the immobilized biocatalyst depends on the reusability factor.