The role of pressure on thin amorphous carbon films deposited using microwave surface wave plasma CVD

We report the effects of gas composition pressure (GCP) on the optical, structural and electrical properties of thin amorphous carbon (a-C) films grown on p-type silicon and quartz substrates by microwave surface wave plasma chemical vapor deposition (MW SWP CVD). The films, deposited at various GCPs ranging from 50 to 110 Pa, were studied by UV/VIS/NIR spectroscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and current–voltage characteristics. The optical band gap of the a-C film was tailored to a relatively high range, 2.3–2.6 eV by manipulating GCPs from 50 to 110 Pa. Also, spin density strongly depended on the band gap of the a-C films. Raman spectra showed qualitative structured changes due to sp³/sp² carbon bonding network. The surfaces of the films are found to be very smooth and uniform (RMS roughness < 0.5 nm). The photovoltaic measurements under light illumination (AM 1.5, 100 mW/cm²) show that short-circuit current density, open-circuit voltage, fill factor and photo-conversion efficiency of the film deposited at 50 Pa were 6.4 μA/cm², 126 mV, 0.164 and 1.4 × 10^− 4% respectively.     

Evaluation of Multipoint Dosing Strategy in a Miniaturized Tubular Reactor: Nitration of Salicylic Acid

A 2D non‐isothermal reaction engineering model for a tubular reactor was developed for a complex reaction network of salicylic acid nitration. The influence of different operating and design parameters was studied to minimize the amount of secondary nitration products and limit the maximum temperature inside the reactor. Critical temperature effects were observed for larger reaction tubes, whereas close to isothermal conditions were perceived in smaller tubes. With single‐point dosing of both reactants, complete conversion can be achieved but formation of secondary nitration products cannot be avoided. For a given number of dosing points, a suitable combination of the operating parameters allowed to achieve complete conversion and better yield of the desired product.     

Toxic effect of environmental acid-stress on the sperm of a hill-stream fish Devario aequipinnatus: a scanning electron microscopic evaluation

Environmental stress due to acidic pH of water was found to be one of the major factors leading to toxic effects on the sperm of a hill-stream fish Devario aequipinnatus of Meghalaya, India. The Scanning Electron Microscopy of the transverse section of testes of the fish collected from its natural habitat with acidic pH (5.6-6.0) showed that the sperms were clumped together and their tails were either absent or were of extremely small length. The acrosome and midpiece were also not well differentiated. When the fingerlings from the natural habitat were reared to maturity in aquarium with water from natural habitat after changing the pH to alkaline range (8.0-8.2), the clumping of the sperm was not observed. The sperm tail was found to be well-developed along with well-differentiated acrosome and midpiece. Since the only change in the water quality parameters of the experimental aquarium as compared to those of the natural habitat was the pH, it is evident that the abnormal features of the sperm observed in fish from natural habitat is mainly because of environmental acid stress.     

A scanning electron microscopic study on the cephalic cuticular sensillae of different larval stages of Antheraea assamensis,an indigenous silkworm species of Northeast India

Scanning electron microscopy revealed the presence of a number of cuticular sensillae on the head of different larval stages of the “Muga” silk moth, Antheraea assamensis. These include four types of sensilla trichodea, bead‐like folded sensilla, two types of sensilla basiconica, and sensory pegs. The study seems to be the first attempt in describing the morphology and distribution pattern of the cephalic cuticular sensillae of different larval stages of the silk moth Antheraea assamensis, an indigenous species of Northeast India. The possible significance of the sensillae in searching behavior of the larval stages during feeding is discussed with the help of available literature. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.     

A variational principle for nonlinear water waves

Summary This paper is concerned with a variational formulation of non-axisymmetric water waves and of two-dimensional surface waves in a running stream of finite depth. The full set of equations of motions for the non-axisymmetric water wave problem in cylindrical polar coordinates and for the two-dimensional surface waves in the running stream in Cartesian coordinates is obtained from a Lagrangian function which is equal to the pressure.With 1 Figure     

Effect of lidocaine and quinidine on focal ventricular arrhythmias induced by subepicardial epinephrine in cats

Subepicardial infusion of epinephrine (EP) in the dose of 3 x 10(-3) M in 2.5 x 10(-3)M CaCl2-0.9% NaCl (calcium-saline vehicle) at the rate of 10 microliters/min in the right ventricular myocardium of mongrel cats weighing between 2.7 and 3.3 kg produced uniform reversible and reproducible focal ventricular arrhythmias of varying intensity and duration. Infusion of two antiarrhythmic agents, lidocaine (LD) and quinidine (QD) in the same site of arrhythmogenesis in equimolar concentration of 3 x 10(-3) M along with EP in the same vehicle reduced incidence, duration, peak and mean frequencies of arrhythmias while the latent period of onset of arrhythmias increased significantly. In present study, quinidine, in equimolar concentration of 3 x 10(-3) M was found to be more effective than lidocaine in antagonizing EP-induced ventricular arrhythmias.     

A realistic linear decision rule for reservoir management

A generalized linear decision rule is presented which takes into account the aspect of spill in a multi-lag LDR model. The proposed rule incorporates past inflow experience to determine the optimum release rules based on a stochastic (linear) programming optimization model. It also prescribes a procedure of determining spill, should it occur, and the method of adjusting the release policy, accordingly, for the subsequent periods, which are directly affected by the spill of the current period. The use of the rule also makes it possible to produce a specification for a reservoir with a smaller capacity by taking liberal constraints on the reservoir freeboard during the monsoon months. The problem is solved, for the purpose of illustration, using the historical data of a river located in central India. Two synthetic streamflow series of a duration of 50 years each are generated under lognormal flow assumption. The prescribed release rules are applied to a hypothetical reservoir with the optimum capacity determined by the linear programming method, and the generated series as the inflow. The results and findings are quite satisfactory.     

Design and in Vitro Evaluation of a Controlled Release Drug Delivery System of Sulfasomidine

A controlled release oral drug delivery system of Sulfasomidine was developed by spray congealing micropelleting technique using gelatin as the embedding matrix. The pellets were hardened by treating with Formalin-Isopropanol mixture. The in vitro release rate studies of Sulfasomidine from the micropelleted dosage form, revealed that the drug release can be prolonged upto eight hours and not more than 39% of the embedded drug released in the first hour of the in vitro dissolution study. The in vitro release patterns correlated with the reported in vivo studies. The method of formulation was optimized.     

Exergo-economic analysis of a 1-MW biomass-based combined cycle plant with externally fired gas turbine cycle and supercritical organic Rankine cycle

This paper deals with exergo-economic modeling and analysis of a 1-MW biomass integrated gasification combined cycle plant that couples an indirectly heated gas turbine (GT) cycle with a supercritical organic Rankine cycle (ORC). The GT produces a fixed net output of 500 kWe, and the organic vapor turbine produces the rest. Saw dust is considered as biomass feed for the gasifier, and toluene acts as ORC working fluid. GT cycle working fluid is heated through a combined combustor-heat exchanger (CHX) unit. Effects of plant parameters, viz. compressor pressure ratio (r _p), gas turbine inlet temperature (TIT) and cold end temperature difference (CETD) of the CHX unit on the thermodynamic and economic performance of the plant are reported. Energy efficiency is maximized at a fixed value of r _p (=6), for all TITs. Higher TIT yields in higher efficiency of the plant. Although increase in CETD lowers the plant efficiency but decreases the size of CHX unit, resulting in the lower capital cost of the unit. Exergo-economic analysis reveals that unit product cost (UPC) is lower at higher TITs and higher r _p values. Levelized unit cost of electricity (LUCE) is also minimized at r _p = 6 for all TITs. Higher TIT also yields lower UPC and LUCE values. Both UPC and LUCE decrease with increase in CETD. For r _p = 6, TIT = 1100 °C and CETD = 300 °C, the plant offers minimum UPC and LUCE values.