Developmental changes in storage proteins and peptidyl prolyl cis–trans isomerase activity in grains of different wheat cultivars

In the present study, storage proteins from five different wheat cultivars were extracted, fractionated and evaluated for their accumulation at different stages of development. SDS–PAGE analysis revealed that the accumulation of high molecular weight glutenin subunits was cultivar and stage dependent. However, low molecular weight glutenin subunits’ accumulation was not altered significantly after 16 days post anthesis in any of the cultivars. The rheological parameters (storage- and loss-modulus) of dough and gluten showed close association with either gliadins or glutenins. Peptidyl prolyl cis–trans isomerase (PPIase) activity, measured at different stages of grains development, showed variability with both the developmental stage and cultivar, and appeared to be primarily due to cyclophilins. Principal component analysis revealed the association of PPIase activity with either gliadin or total proteins, suggesting their significant role in the deposition of storage proteins in wheat.     

Fuzzy controlled backpropagation neural network for tool condition monitoring in face milling

The performance of a fuzzy controlled backpropagation neural network has been studied to predict the tool wear in a face milling process based on simple process parameters and sensor signal features. The results show the potentiality of the method in comparison to the standard backpropagation neural network and one of its variants. The speed of convergence, accuracy of prediction and total time of system development make fuzzy controlled backpropagation an attractive technique amenable for online tool condition monitoring.     

Understanding the swelling of poly (N-isopropyl acrylamide) gels through the study of free volume hole size distributions using positron annihilation spectroscopy

Poly (N-isopropyl acrylamide) gels were prepared by UV polymerization with different degree of cross-linking in different solvents. Ethylene glycol dimethacrylate and penta-erythritol tetra-acrylate were used as cross-linkers, and methanol and dimethyl formamide (DMF) were used as solvents for gel preparation. The free volume fraction and hole size distribution in the dry gels were measured using positron annihilation lifetime spectroscopy. The equilibrium swelling of the samples in water was measured at room temperature. Both swelling properties of gels and the free volume distributions were seen to be sensitive to the amount, type, and functionality of cross-linkers as well as solvent medium used for synthesis. The gels prepared in DMF showed poor swelling properties than those prepared in methanol. The mean free volume hole size was higher while the variance of hole size distribution was smaller in the gels prepared in DMF medium compared to those prepared in methanol. The free volume fractions in the gels were found to be inversely correlated to the extent of equilibrium swelling for similar chemical compositions. The possible reasons are discussed.     

Transport phenomena in laser surface alloying

A three dimensional, transient model is developed for studying heat transfer, fluid flow and mass transfer for the case of a single-pass laser surface alloying process. The numerical study is performed in a co-ordinate system fixed to the laser which moves with a constant scanning speed. The coupled momentum, energy and species conservation equations are solved using a finite volume technique. Phase change processes are modelled using a fixed-grid enthalpy-porosity technique, which is capable of predicting the continuously evolving solid-liquid interface. The three-dimensional model is able to predict the species concentration distribution inside the molten pool during alloying, as well as in the entire cross section of the solidified alloy. Corresponding experimental results show a good qualitative agreement with the numerical predictions with regard to pool shape and final composition distribution.     

Residence time distribution and oxygen transfer in a novel constructed soil filter

BACKGROUND: The constructed soil filter (CSF), also known as soil biotechnology is a system for water renovation, which makes use of formulated media, culture of soil micro‐ and macro‐organisms, additives and plantation to purify water and wastewater. The process gives benefits in terms of applicability across very small to large scale, natural aeration, absence of moving parts, no biological sludge generation, odor free green aesthetic ambience. RESULTS: Residence time distribution (RTD) studies were carried out using laboratory scale CSF. Pulse potassium bromide tracer tests were carried out to determine RTD, and the Peclet number found to be 9–13 for a 2 m bed, and 2–3 for a 0.30 m bed with oxygen transfer of 0.08 h^?1. CONCLUSION: The two‐channel dispersion model for flow behavior shows a good fit to the experimental data, indicating a reactor Peclet number 9–13 for a 2 m bed and 2–3 for a 0.3m bed. Oxygen transfer studies carried out using various methods gave an oxygen transfer coefficient of about 0.08 h^?1. Wastewater purification studies indicate overall COD removal rate of around 50 mg L^?1 h^?1, suggesting that highly aerobic conditions are prevalent in the CSF system. Copyright © 2009 Society of Chemical Industry     

Nonlinear analysis of nuclear coupled density wave instability in time domain for a boiling water reactor core undergoing core-wide and regional modes of oscillations

The objective of the paper is to develop a nuclear coupled thermal-hydraulic model in order to simulate core-wide (in-phase) and regional (out-of-phase) stability analysis in time domain within the limitation of desktop research facility for a boiling water reactor subjected to operational transients. The integrated numerical tool, which is a combination of thermal-hydraulic, neutronic and fuel heat conduction models, is used to analyze a complete boiling water reactor core taking into account the strong nonlinear coupling between the core neutron dynamics and primary circuit thermal-hydraulics via the void-temperature reactivity feedback effects. The integrated model is validated against standard benchmark and published results. Finally, the model is used for various parametric studies and a number of numerical simulations are carried out to investigate core-wide and regional instabilities of the boiling water reactor core with and without the neutronic feedback effects. Results show that the inclusion of neutronic feedback effects has an adverse effect on boiling water reactor core by augmenting the instability at lower power for same inlet subcooling during core-wide mode of oscillations, whereas the instability is being suppressed during regional mode of oscillations in presence of the neutronic feedback. Dominance of core-wide instability over regional mode of oscillations is established for the present case of simulations which indicates that the preclusion of the former will automatically prevent the latter at the existing working condition.     

Large Eddy Simulation of Turbulent Slot Jet Impingement Heat Transfer at Small Nozzle-to-Plate Spacing

We present fluid flow and heat transfer of a slot jet impingement heat transfer at a small value of the nozzle-to-plate spacing at which a secondary peak in the Nusselt number is observed. Large eddy simulation has been performed with a finite-volume-based computational fluid dynamics code and using a dynamic Smagorinsky model. The optimum domain size and grid for large eddy simulation (LES) have been produced based on LES computations on a coarse mesh and Reynolds-averaged Navier–Stokes-based computations. Two inflow conditions, namely, using the vortex method and no perturbations, were compared. The present LES results, using the vortex method, capture the secondary peak in the Nusselt number better as compared to the case with no perturbations. Results show that mean velocity profile in the stagnation region deviates from the standard law of the wall. Further, large-scale vortical structures were observed near the location of the secondary Nusselt number peak. Increases in both the streamwise and wall normal turbulence fluctuations are observed near the secondary peak in the Nusselt number. The secondary peak in Nusselt number is found to be associated with the combined effect of flow acceleration and an increase in the turbulence kinetic energy.     

Design considerations for p-i-n thyristor structures

An analysis of a high-voltage gate turn-off (GTO) thyristor structure with a double-layered n base (p-i-n structure) is presented. From integration of Poisson's equation, an expression for the forward-blocking voltage at the onset of avalanche breakdown is obtained. Simple design criteria are developed to calculate the optimal thickness and doping density of the n base of a conventional pnpn structure designed for a specific voltage-blocking capability. The same principle is applied to design for the doping densities and thicknesses of the high-resistivity region and the buffer layer of the p-i-n GTO structure. The forward-blocking voltage, as well as the on-state voltage (at a current density of 300 A cm^-2) is predicted for a wide range of base layer thicknesses and doping densities to illustrate the available tradeoff options. Lowest on-state power dissipation for high blocking voltages (>6000 V) is predicted for a doping level of 5×10¹² cm^-3 in the high-resistivity layer     

Effect of curing conditions and ionic additives on properties of fly ash-lime compacts

In the present work the reaction between fly ash and lime in fly ash-lime compacts under water curing and steam curing conditions was studied thoroughly in relation to the processing conditions. Fly ash from different sources were collected, characterized, mixed with lime in different ratios and compacted. The compacts were cured with water and steam separately. The reduction in the free CaO content in these compacts was measured as a function of curing time and curing process. Role of two ionic additives, FeCl₃ and MgCl₂, on the reaction between fly ash and lime was also investigated by measuring the free CaO content. Kinetics of these reactions was studied by determining the reaction order and rate constants with respect to the free CaO content and it was observed that the curing conditions and additives affected the reaction kinetics significantly.     

A New Chebyshev-like Low-pass Filter Approximation

A new Chebyshev-like low-pass filter approximation is proposed for which the order is always odd and hence there is no problem for doubly terminated LC ladder realization. Flexibility of shaping the response and lower Q values of complex poles appear to be the major advantages of the new approximation as compared to the normal Chebyshev filter.