Heat equation and its comparative solutions

In this paper we will conduct an analytic comparative study between the powerful Adomian method and the traditional separation of variables method. This is achieved by handling homogeneous and non-homogeneous boundary value problem for one-dimensional heat equation. The study shows the reliability and efficiency of Adomian method. Adomian method provides the solution in a rapidly convergent series through evaluating elegantly computable components.     

Impact modification of SAN using NR-g-SAN copolymers

The paper demonstrates the efficacy of natural rubber-g-poly (styrene-co-acrylonitrile) (NR-g-SAN) copolymers as impact modifier for SAN. The impact behaviour of SAN /NR-g-SAN blends were studied as a function of cross-link density of NR, percent grafting, rubber content in the blend and the AN content in the grafted chain. The cross-link density of NR had no significant effect on impact strength of the blends whereas increase in percent grafting (PG) of the rubber significantly improved the impact strength. Thus the impact strength increased four times when the PG of the rubber was increased from 34.2 to 65%. Further increase in PG decreased the impact strength. Similar trend was observed on increase in the rubber content, the maximum impact strength was observed at 20% rubber. The impact strength also depended on the acrylonitrile content of the grafted chain. Tensile and flexural strength and modulus of these blends were not influenced by PG and AN content in the grafted chain whereas these properties decreased with the increase in the rubber content. Scanning electron microscopic studies of the impact fractured surfaces showed cavitation of rubber particles and craze induced matrix deformation. Dynamic mechanical studies confirmed the two-phase structure of these blends.     

Use of leaf enriching harvesting methods to increase the yield of leaf protein concentrate from lucerne

A prototype leaf stripping machine and a conventional forage harvester with a raised header were used to obtain high protein lucerne (alfalfa) fractions. The stripped lucerne leaves and lucerne tops contained 26.2 and 27.2% protein, respectively. Pilot-scale extraction of the ground leaves and the ground tops resulted in leaf protein concentrate (LPC) yields of 18.8 and 20.0%, respectively, compared with 12.8 and 15.7% for the appropriate whole lucerne control. LPC yields as high as 27.4% were obtained by the addition of lucerne solubles to the lucerne tops prior to grinding. Low LPC yields (4.0–8.0%) were obtained from the lucerne stem fraction. After processing, the press cake fraction from the leaf-enriched feed materials still contained over 17% protein.     

Pyrolysis of Natural Gas: Effects of Process Variables and Reactor Materials on the Product Gas Composition

High‐temperature pyrolysis of natural gas is the basis of the standard method for the manufacture of acetylene. The study of methane pyrolysis was designed to find optimum process conditions that would produce high yields of acetylene with minimal carbon formation. High temperatures and short residence times enhanced the selectivity for acetylene, while hydrogen dilution was found to suppress the generation of carbonous products. Carbon formation on reactor surfaces over time may be mainly responsible for the misalignment of predicted and measured product gas compositions, as the mechanisms reported do not consider the surface chemistry. In essence, the pyrolysis system favors the highest possible temperature and shortest possible residence time, suggesting that the selection of reactor materials is the key for pyrolysis process optimization. The operating temperature is likely dictated by the physical properties of the reactor materials rather than the selection of optimal pyrolysis conditions.     

Phosphorylcholine‐Substituted ROMP Polyolefin Coatings Provide Fouling Resistance to Membrane Materials

The design and synthesis of new fouling‐resistant coating materials, specifically PC‐substituted polyolefins, and their application to water purification membranes is described. Greatly improved fouling resistance is found for coated membranes subjected to environmentally relevant emulsified oil foulants. The coating method proves effective for reducing fouling on both UF and RO membranes, and for maintaining high rejection of organic material and salt. Providing membranes of various types with a coating that simultaneously gives high flux, fouling resistance, and foulant rejection represents a significant advance in membrane materials, and a promising route to extend membrane applications beyond what has been possible using conventional, known materials.

     

Tailored Hydrogel Membranes for Efficient Protein Crystallization

Crystallization still represents the bottleneck in the process of protein structure determination at high resolution, despite high‐throughput structural genomics programs requiring optimized crystallization strategies regarding crystal quality, time, success rate, reproducibility, and used protein amount. On the other hand, the development of suitable materials for controlled heterogeneous nucleation might facilitate biomacromolecular crystallization in a variety of experimental conditions which are not conventionally fruitful. Here, the possibility to fabricate hydrogel membranes displaying controlled chemical composition and nanostructure and to use them as heterogeneous supports for biomacromolecular crystallization is demonstrated. Diverse gel morphologies are obtained by controlling phase separation kinetics during gel layer formation on membrane support. These composite materials are found to increase the efficiency of the crystallization process so that crystals with enhanced diffraction properties are produced at lower protein concentration than conventional technique, thus affording the possibility to improve current approaches to protein crystallization and to be adapted to specific targets.     

Radon and Natural Ventilation in Newer Danish Single-Family Houses

Abstract To investigate the effect of ventilation on indoor radon (²²²Rn), simultaneous measurements of radon concentrations and air change rates were made in 117 Danish naturally ventilated slab-on-grade houses built during the period 1984–1989. Radon measurements (based on CR-39 alpha-track detectors) and air change rate measurements (based on the perfluorocarbon tracer technique; PFT) were in the ranges 12–620 Bq m^?3 and 0.16?0.96 h^?1, respectively. Estimates of radon entry rates on the basis of such time-averaged results are presented and the associated uncertainty is discussed. It was found that differences in radon concentrations from one house to another are primarily caused by differences in radon entry rates whereas differences in air change rates are much less important (accounting for only 80,0% of the house-to-house variation). In spite of the large house-to-house variability of radon entry rates it was demonstrated, however, that natural ventilation does have a significant effect on the indoor radon concentration. Most importantly, it was found that the group of houses with an air change rate above the required level of 0.5 h^?1 on average had an indoor radon concentration that was only 50% (0.5±0.1) of that of the group of houses with air change rates below 0.5 h^?1. The reducing effect of increased natural ventilation on the indoor radon concentration was found to be due mainly to dilution of indoor air. No effect could be seen regarding reduced radon entry rates.     

On the location of Steiner points in uniformly-oriented Steiner trees

We give a fundamental result on the location of Steiner points for Steiner minimum trees in uniform orientation metrics. As a corollary we obtain a linear time algorithm for constructing a Steiner minimum tree for a given full topology when the number of uniform orientations is λ=3m,m?1.