Entropy Analysis of a Coupled‐Convection Flow through a Vertical Channel Partially Filled by a Porous Medium with Injection/Suction and Slip Boundary Conditions

Flow fields, thermal fields, and entropy generation have been investigated for fully developed mixed convection flow between two vertical porous plates. The vertical channel is partially filled by a porous medium, and channel walls are subjected to a constant injection velocity at the left wall and constant suction velocity at the right wall. The viscous dissipation effects and velocity slip for the longitudinal component of the velocity at the channel walls are also taken into account. The momentum and energy equations for the mixed convection problem in the vertical channel are solved by means of the perturbation series method, by taking perturbation parameter proportional to the Brinkman number. For the present problem, numerical solution is also obtained and compared with the analytical solution. The effects of various pertinent parameters on the velocity distribution, temperature distribution, entropy generation rate, and Bejan number are investigated and discussed graphically.     

Acacia saligna as a fodder tree for desert livestock and the interaction of its tannins with fibre fractions

Acacia saligna was examined as potential fodder for sheep (27.4 kg) and goats (14.8 kg) raised in arid and semi-arid areas. This leguminous tree remains green all year and can be grown in deserts using only runoff water. Phyllodes collected in March had a crude protein content of 12.5% dry matter (DM) and high tannin content (tannins as tannic acid equivalent to 11.3% and condensed tannins as leucocyanidin equivalent to 8.3% DM). DM intake was low, amounting to 0.80% and 1.05% body mass daily for sheep and goats, respectively. Sheep lost 227 g day^?1 and goats 196 g day^?1 while on this diet. Dry matter, organic matter and energy digestibilities were low in both species but were higher for goats than for sheep, and negative digestibilities were measured for acid detergent fibre (ADF) and acid detergent lignin (ADL). Metabolisable energy intake for goats was 121.9 kJ kg^?0.75 day^?1 and for sheep was 78.6 kJ kg^?0.75 day^?1. Apparent N digestibility was 17.5% and 0.9% for goats and sheep, respectively, and both species were in negative N balance of 0.25–0.30 g kg^?0.75 day^?1. Total water intake and output were higher in sheep than in goats. Extractable tannins were virtually absent in faeces in both species, however, output of condensed tannins and protein in the ADF and ADL fractions were substantially higher. This showed the presence of tannin-protein complexes in these fractions which explained the negative digestibilities of ADF and ADL. It was concluded that Acacia saligna could not be used as a sole dietary source for small ruminants because of low intake and negative nitrogen balance. This was due mainly to the high tannin content. However, the tree might have a potential as a supplementary fodder due to its high crude protein content.     

Amino acid composition,antinutrients and allergens in the peanut protein fraction obtained by an aqueous enzymatic process

Enzyme-assisted aqueous extraction (EAE) of peanut kernel was used to extract oil and protein. The aqueous fraction (AF) obtained by EAE had a better essential amino acid profile than the residues obtained by solvent extraction (Rs) and cold pressing (Rc). No major difference in the trypsin inhibitor activity among AF, Rs and Rc was observed; however, the trypsin inhibitor activity was drastically reduced in the residue obtained after EAE. AF was subjected to MALDI-TOF/MS, revealing it to be rich in peptides (107) with molecular masses from m/z 700 to 2369 Da. AF had an extremely low phytate content and was rich in peptides, which could be used as a food supplement. ESI-MS/MS data were used for the identification of major peanut allergens, viz., Ara h1, h3, h6–8. Their allergenic potential needs to be established.     

Non-starch polysaccharides and their role in fish nutrition – A review

The success and sustainability of aquaculture depends on minimising the operational cost of feed that in general comprises 50–60% of the total cost in intensive farming. The major feed ingredient, fish meal, is expensive and there is increasing competition with other livestock industries for the available static supply of fish meal. Hence, the incorporation of plant-derived materials in fish feeds is receiving increasing attention. One of the main constraints in the utilisation of plant ingredients in aquaculture is the presence of indigestible carbohydrates, which consist primarily of non-starch polysaccharides (NSPs). These form a part of the cell wall structure of cereals and legumes. The presence of NSPs in the diet interferes with feed utilisation and adversely affects performance of the animal. Supplementation of NSP-degrading enzymes in feed mitigates the adverse effects of NSPs. The effects of NSPs in pigs and poultry have been widely studied; however little information exists for fish. This review synthesizes the available information on fish and highlights the knowledge gaps. It is hoped that this review will provide a momentum to the research on the roles of NSPs in fish nutrition and physiology and on the efficient use of NSP-degrading enzymes.     

Protein concentrate from Jatropha curcas screw‐pressed seed cake and toxic and antinutritional factors in protein concentrate

BACKGROUND: Jatropha curcas seeds are highly toxic to livestock. The presence of phorbol esters and antinutrients such as trypsin inhibitor, lectin and phytate and the high level of shells in the seed cake prevent its use in animal diets. Using the principle of isoelectric precipitation, the conditions for preparation of the protein concentrate from oil‐containing seed cake and defatted seed cake were optimised and the contents of phorbol esters and antinutrients were determined. RESULTS: The recovery of protein concentrate was highest when the proteins from the seed cakes were solubilised at pH 11 for 1 h at 60 °C and the precipitation of these proteins was done by lowering the pH to 4. Under these conditions, over 53% of the total proteins present in the seed cakes were recovered in the protein concentrates. The protein contents in the protein concentrates obtained from the oil‐containing seed cake and defatted seed cake were 760 and 820 g kg^?1 respectively. Substantial amounts of phorbol esters were present in the protein concentrates (0.86–1.48 mg g^?1). Trypsin inhibitor was present at an approximately tenfold higher level in the protein concentrates than in the seed cakes. Lectin and phytate were also present at high levels, but their levels were lower than in the seed cakes. Tannins were present in negligible amounts. CONCLUSION: To make the protein concentrate from Jatropha seed cake fit for use as an ingredient in livestock feed, phorbol esters must be removed and trypsin inhibitor and lectin inactivated by heat treatment. The adverse effects of phytate could be mitigated by addition of phytase in the diet. Copyright © 2008 Society of Chemical Industry     

A novel approach for evaluation of polymeric interface materials for chemical sensors using alternate indirect methods

The heart of a chemical sensor based on bulk or surface acoustic wave devices is a polymer‐coated piezoelectric substrate that selectively sorbs and concentrates the target analyte vapors. The development of such sensors often necessitates the screening and evaluation of suitable polymeric interface materials meeting the specified sensitivity and selectivity toward the analytes of interest. The magnitude and dynamics of sorption–desorption of the vapors in the polymer and the extent of polymer–vapor interactions largely determine the performance of a sensor. The standard protocol used for the purpose is rather tedious, involving the generation and calibration of individual analyte vapors, with stringent control on temperature, humidity, and test parameters. This article outlines four different alternative techniques based on mass uptake of the analyte vapors, on its partitioning in polymers, or both, which in combination can determine the characteristics of an interface material used for coating a piezoelectric substrate in acoustic wave‐based chemical sensors. These methods were applied to poly(ethylene maleate), a representative interface material. The analytes ranged from volatile organic chemicals to sarin—a chemical warfare agent—and its simulant, dimethyl methylphosphonate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3428–3432, 2004     

Synthesis and Application of Palm Fatty Acid Distillate Based Alkyd Resin in Liquid Detergent

Palm fatty acid distillate (PFAD) is the by-product obtained during physical refining of crude palm oil, which mainly consists of free fatty acids along with minor amounts of glycerides, bioactive compounds such as tocopherols, tocotrienols, phytosterols, squalene, other hydrocarbons. In the present work, an eco-friendly alkyd resin was prepared using sustainable feedstock such as PFAD along with rosin. The various physico-chemical properties of PFAD-based alkyd resin (PFAD-AR) such as acid value, saponification value, viscosity and volatile matter were determined and compared to palm oil based alkyd resin (PO-AR). The structural properties of the alkyd resins were investigated using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopic techniques. The study presents the utilization of PFAD-based alkyd resin with sodium lauryl sulfate (SLS) and sodium lauryl ether sulfate (SLES) in the liquid detergent formulation. The performance properties of the PFAD-based alkyd resin liquid detergent formulations such as surface tension, wetting power and detergency were comparable with palm oil based alkyd resin liquid detergent formulations and with commercial liquid detergent (CLD). Surface tensions of liquid detergent formulations varied from 20 to 30 mN/m with decrease in concentration. The foaming properties of alkyd resin based liquid detergents are reduced with the increase in the amount of alkyd resin polymer in the formulations. Therefore, it has potential application as a foam reducer in detergent for washing machines.     

Study of Permeation of Bis(2-Chloroethyl)Sulfide Through Elastomer Membranes

An investigation was made of the effect of the nature of elastomer, thickness of the membrane and its formulation, and the temperature and relative humidity of the surroundings, on the permeation of bis(2-chloroethyl)sulfide (SM), a well-known chemical warfare agent, through solution-cast elastomer membranes. The permeation was evaluated in terms of the breakthrough time of the agent through the membrane, using the spot disk test and the weight gain method. Butyl rubber exhibited the highest permeation resistance, which increased linearly with thickness and was increased by incorporation of an optimum of 20 phr carbon black in the membranes. Increase in temperature and relative humidity lowered the permeation resistance. The observed data were correlated with permeation parameters and it is postulated that permeation of SM through elastomers is non-Fickian in nature.