A Hybrid Scheme for the Solution of the Bivariate Spatially Distributed Population Balance Equation

The advantages of the generalized fixed pivot technique as extended to mass transfer and the quadrature method of moments are hybridized to reduce the bivariate spatially distributed population balance equation describing the coupled hydrodynamics and mass transfer in liquid‐liquid extraction columns. The key idea in the hybridization technique is to use the available moments furnished by the generalized fixed pivot technique to find the abscissa and weights for the Gaussian‐quadrature based approach, in an attempt to evaluate the integrals over unknown droplet densities. To implement the quadrature method of moments efficiently, an explicit form for the abscissas and weights is derived based on the product‐difference algorithm as described by McGraw [1]. The proposed technique is found to reduce the discrete system of partial differential equations from 2 M_x + 1 to M_x + 2, where M_x is the number of pivots or classes. The spatial variable is discretized in a conservative form using a couple of recently published central difference schemes. The numerical predictions of the detailed and reduced models are found to be almost identical, accompanied by a substantial reduction of the CPU time as a characteristic of the hybrid model.     

Microfabricated Hydrogen Sensitive Membranes

Thin, defect‐free palladium, palladium/copper and palladium/silver hydrogen absorbing membranes were microfabricated. A dual sputtering technique was used to deposit the palladium alloy membranes of only 1 μm thickness on a nonporous silicon substrate. Advanced silicon etching (ASE) was applied on the backside to create a mechanically stable support structure for the thin films. Performance evaluation was carried out for different gases in a temperature range of 20 °C to 298 °C at a constant differential pressure of 110 kPa at the two sides of the membrane. The composite membranes show an excellent permeation rate of hydrogen, which appears to be 0.05 Pa m³ s^–1 and 0.01 · 10^–3 Pa m³ s^–1 at 20 °C for the microfabricated 23 % silver and the 53 % copper composite membranes, respectively. The selectivity to hydrogen over a gas mixture containing, in addition to hydrogen, carbon monoxide, carbon dioxide and nitrogen was measured. The mass spectrometer did not detect any CO₂ or CO, showing that the membrane is completely hydrogen selective. The microfabricated membranes exhibit both high mechanical strength (they easily withstand pressures up to 4 bar) and high thermal stability (up to 650 °C).     

Solving pinball routing,race condition and loop formation issues in nested mobile networks

In order to manage the mobility of Mobile Network, IETF has specified NEMO protocol. However, the standard NEMO solution does not specify any Route Optimization mechanism, as a result of which the data is always exchanged over a bi-directional tunnel maintained between the MNet and its respective Home Agent. This in-efficient routing of packets imposes several performance issues that gets compounded for nested Mobile Networks, where data packets will be tunneled/detunneled multiple times undergoing repeated levels of encapsulations/decapsulations. Such routing of packets, commonly termed as pinball routing, is considered a serious performance limitation and its adverse effect is maximum during intra-nest communication, i.e., between two inter-communicating nodes existing within the same MNet domain. Another issue concerned with nested mobile networks is loop formation and race condition between two competing Mobile Routers.Previously, we had proposed a basic RO solution called NERON. In this paper we extend the base NERON protocol solution to solve issues due to Pinball routing phenomena, and to avoid loop formation and race condition between contending Mobile Routers.     

Micronutrient fortification of wheat flour: Recent development and strategies

Deficiencies of iron, zinc and vitamin A have been a focus of the governments and world organizations for decades and extensive efforts are being made to address this malnutrition. Being a popular and most common dietary staple of the population living in sub-continent and developing countries, wheat flour (WF) has gained a significant attention as a suitable vehicle for micronutrient fortification. Fortification of wheat flour has been established as an appropriate strategy to curtail micronutrient deficiencies especially in the developing economies. Extent of the prevalence of micronutrient deficiencies, their consequences, selection of a suitable vehicle, choice of fortificants and their levels and storage stability, acceptability and bioavailability of iron and zinc fortified WF are the key points of discussion in the current review. This review further highlights multifaceted issues pertaining to the appropriateness and suitability of fortification over other intervention strategies, ecological needs and fortification success stories and advantages of simply adding fortificants to flour to meet nutritional requirements of vulnerable groups. The authors have attempted to encompass the subject matter based on their research endeavors made in this direction.     

Nutraceutical and Functional Scenario of Wheat Straw

In the era of nutrition, much focus has been remunerated to functional and nutraceutical foodstuffs. The health endorsing potential of such provisions is attributed to affluent phytochemistry. These dynamic constituents have functional possessions that are imperative for cereal industry. The functional and nutraceutical significance of variety of foods is often accredited to their bioactive molecules. Numerous components have been considered but wheat straw and its diverse components are of prime consideration. In this comprehensive dissertation, efforts are directed to elaborate the functional and nutraceutical importance of wheat straw. Wheat straw is lignocellulosic materials including cellulose, hemicellulose and lignin. It hold various bioactive compounds such as policosanols, phytosterols, phenolics, and triterpenoids, having enormous nutraceutical properties like anti-allergenic, anti-artherogenic, anti-inflammatory, anti-microbial, antioxidant, anti-thrombotic, cardioprotective and vasodilatory effects, antiviral, and anticancer. These compounds are protecting against various ailments like hypercholesterolemia, intermittent claudication, benign prostatic hyperplasia and cardiovascular diseases. Additionally, wheat straw has demonstrated successfully, low cost, renewable, versatile, widely distributed, easily available source for the production of biogas, bioethanol, and biohydrogen in biorefineries to enhance the overall effectiveness of biomass consumption in protected and eco-friendly environment. Furthermore, its role in enhancing the quality and extending the shelf life of bakery products through reducing the progression of staling and retrogradation is limelight of the article.     

Numerical solution of the spatially distributed population balance equation describing the hydrodynamics of interacting liquid-liquid dispersions

In liquid-liquid contacting equipment such as completely mixed and differential contactors, droplet population balance based modeling is now being used to describe the complex hydrodynamic behavior of the dispersed phase. For the hydrodynamics of these interacting dispersions this model accounts for droplet breakage, droplet coalescence, axial dispersion, exit and entry events. The resulting population balance equations are integro-partial differential equations (IPDE) that rarely have an analytical solution, especially when they show spatial dependency, and hence numerical solutions are sought in general. To do this, these IPDEs are projected onto a system of convective dominant partial differential equations by discretizing the droplet diameter (internal coordinate). This is accomplished by generalizing the fixed-pivot (GFP) technique of Kumar and Ramkrishna (Chem. Eng. Sci. 51 (1996a) 1311) handling any two integral properties of the population number density for continuous flow systems by treating the inlet feed distribution as a source term. Moreover, the GFD technique has the advantage of being free of repeated or double integral evaluation resulting from the weighted residual approaches such as the Galerkin's method. This allows the time-dependent breakage and coalescence functions to be easily handled without appreciable increase in the computational time. The resulting system of PDEs is spatially discretized in conservative form using a simplified first order upwind scheme as well as first- and second-order non-oscillatory central differencing schemes. This spatial discretization avoids the characteristic decomposition of the convective flux based on the approximate Riemann solvers and the operator splitting technique required by classical upwind schemes. The time variable is discretized using an implicit strongly stable approach that is formulated by careful lagging of the non-linear parts of the convective and source terms. The algorithm is tested against analytical solutions of the simplified population balance equation for a differential liquid-liquid extraction column through four case studies. In all these case studies the discrete models converge successfully to the available analytical solutions and to solutions on relatively fine grids when the analytical solution is not available. Realization of the algorithm is accomplished by comparing its predictions to experimental steady-state hydrodynamic data of a laboratory scale rotating disc contactor of diameter. Practically, the combined algorithm is found fast enough for the computation of the transient and steady-state hydrodynamic behavior of the continuously and spatially distributed interacting liquid-liquid dispersions.     

Effect of modified whey protein concentrates on empirical and fundamental dynamic mechanical properties of frozen dough

Dairy byproduct proteins are considered natural functional additives having the ability to interact with the starch and gluten network in a dough system and thus behave as dough improvers. Native whey proteins have negative effect in bread making so whey protein concentrates modified to increase viscosity in solution (mWPC) might overcome undesirable weakening of the gluten network which usually occurs in frozen dough products during prolonged times in frozen storage. The objective of this research project was to determine the effect of mWPC on empirical and fundamental dynamic rheological properties of wheat flour dough. The results for empirical rheological studies showed that addition of mWPC had significant effects on mixographic parameters and also increased values of mixing time and peak height percentage. The results for the fundamental mechanical properties of the frozen dough revealed an increase in the values of G′ with the increase in the frequency, along with an upward trend with increasing temperature, but the highest values were obtained after cooling. Addition of mWPC in the dough treatments induced softening in the dough system, as shown by the decrease in the values of the viscoelastic moduli. Rheological and textural changes in the bakery products made from frozen dough could be imparted by the incorporation of modified whey protein concentrates as dough improvers.     

Effect of Thermal Treatment on Meat Proteins with Special Reference to Heterocyclic Aromatic Amines (HAAs)

Meat is one of the most imperative protein sources available with respect to its production and consumption. It is the richest source of some valuable nutrients like proteins, essential amino acids, polyunsaturated fatty acids, vitamins, and minerals like iron, zinc, and selenium. Thermal treatment produces conformational changes in protein structure as well as flavor, texture, and appearance, and chemical properties of the ingredients are also changed. Heterocyclic aromatic amines (HAAs), potent mutagens/carcinogens, are formed during the cooking of meat at high temperature. The review paper highlights the effects of various cooking methods, i.e., pan-frying, deep-frying, charcoal grilling, and roasting, on the formation of HAAs. The levels of HAAs produced in cooked meats vary depending upon the cooking method, time of cooking, and the type of meat being cooked. Metabolic behavior of HAAs is very unique, they interfere in the activity of many enzymes, modify the metabolic pathways, and lead to the adduct formation of DNA. The application of black pepper and several other spices during processing may reduce the formation of these (HAAs) mutagenic compounds.     

Isolation and Characterization of Buffalo Milk Lysozyme

Lysozyme is a commercially valuable enzyme, and is applied in many fields, concerning products such as foods, drugs, and the like. In this work, lysozyme was isolated and purified from buffalo milk using sephadex G-50 and cation exchanger carboxymethyl cellulose. Lysozyme active fractions from buffalo milk were assayed against Gram positive substrate Micrococcus luteus at 450 nm and a decline in absorbance of 0.001 per min was observed. The optimum activity of lysozyme (158.3 ± 1.7 units/mL) was at 7.5 pH and 37°C temperature. Lysozyme activity at pasteurization temperatures 62.5°C, 30 min and 75°C, 15 s were (156.08 ± 1.03 and 156 ± 2 units/mL) not affected significantly; however, 47% activity of lysozyme was reduced at 100°C for 5 min. Antibacterial susceptibility testing of lysozyme (chicken egg white lysozyme and buffalo milk lysozyme) was performed on Micrococcus luteus (ATCC 4698) and Escherichia coli (ATCC 25235). Both lysozymes showed no inhibition effect against Escherichia coli.