Studies on miscibility of dehydrated castor oil epoxy blend with poly(methyl methacrylate)

Oil epoxies can be used as plasticizers in the processing of hard polymers. For this purpose dehydrated castor oil epoxy (DCOE), a product from sustainable resource, has been chosen for blending with poly(methyl methacrylate) (PMMA) to investigate the compatibility of this blend pair. Blends of DCOE/PMMA were prepared in the weight ratios 80/20, 60/40, 40/60, and 20/80 through solution method by mixing in dimethylsulphoxide. Free‐standing films of the blend were cast and the miscibility of the two components was investigated by viscosity and ultrasonic measurements, which provided valuable information on the degree of compatibility of the pairs of blends in solution. The compatibility was also examined by differential scanning calorimetry and scanning electron microscopy. All the studies revealed that DCOE was immiscible with PMMA. However, the appearance and texture of the films were not found to show any visible change over several months, which indicates stability of this blend system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3094–3100, 2006     

Kinetics of zirconium ions adsorption on activated charcoal from aqueous solutions

The batch kinetics of adsorption of the zirconium ions from aqueous solutions on activated charcoal has been investigated over a wide range of concentration of zirconium ions (1.0–5.0 g/l) and temperatures (10–50°C). The adsorption process of zirconium ions proceeds via two stages; the first stage is rather fast, followed by a much slower one. The Bangham equation was used to study the kinetics of the zirconium ions' adsorption on activated charcoal. It is observed that the diffusion of zirconium ions into the pores of the activated charcoal controls the kinetics of the adsorption process. Moreover, zirconium ion adsorption obeys the Freundlich and Langmuir isotherms in the concentration range studied. The adsorption equilibrium constant (k_c) values for zirconium ions adsorption on activated charcoal have also been calculated at different temperatures. Various thermodynamic quantities, ΔG, ΔH, and ΔS were computed from k_c values. The results showed that the adsorption of zirconium ions on activated charcoal is an endothermic process.     

Pseudothermoset blends of poly (methyl methacrylate) and polypyrrole morphological,thermal, and conductivity studies

Blends of poly (methyl methacrylate) (PMMA)/Polypyrrole (PPy) were synthesized by emulsion polymerization of methyl methacrylate (MMA) and in situ oxidative polymerization of pyrrole (Py) with varying concentrations of Py and ferric chloride. The influence of the varying concentrations of ferric chloride, Py, and MMA on the morphological, spectral, thermal, and conductance characteristics of the blends were investigated. Hydrogen bonding between PPy and PMMA was inferred from FTIR studies that indicate blend formation. DSC and TGA analysis of the blends were done. A curious thermal behavior was observed that the blends lost their elasticity and flexibility on heating and turned into rigid and brittle material. DSC thermogram did not show glass transition temperature, indicating molecular and chain reorganization on heating. We have therefore called these blends pseudothermoset. The physicomechanical characteristics of the films of the blends were found to deteriorate with the increased ratio of ferric chloride in the blend, causing a decrease in the conductivity. Maximum conductivity (percolation threshold) was found at 14 wt % loading of Py in the blend (1.6 × 10^?3 S cm^?1), which was further correlated with the morphology of the films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 82–91, 2004     

Recent Trends and Applications of Encapsulating Materials for Probiotic Stability

The importance of probiotics and their live delivery in the gastrointestinal tract has gained much importance in the recent past. Many reports have indicated that there is poor viability of probiotic bacteria in dairy based products, both fermented and non-fermented, and also in the human gastro-intestinal system is questionable. In this case, microencapsulation is the most significant emerging and efficient technology that is being used for the preservation of probiotics against adverse environmental conditions. Apart from different techniques of microencapsulation, various types of encapsulating materials are also used for the process, namely, alginate, chitosan, carrageenan, gums (locust bean, gellan gum, xanthan gum, etc.), gelatin, whey protein, starch, and compression coating. Each one of the encapsulating materials has its own unique characteristics of capsule formation and provision of shape, appearance, and strength to microbeads. The type of encapsulating material also influences the viability of probiotics during storage, processing, and in the gastrointestinal tract. The effectiveness of any material depends not upon its capsule forming capability, strength, and enhancing viability but also on its cheapness, availability, and biocompatibility. So, added convenience and reduced packaging costs may also be used to offset the cost of encapsulating one or more ingredients. Encapsulated forms of ingredients provide a longer shelf life for the product.     

The Housing and Location Preferences of Adelaide Residents

There has been a growing mismatch between household and housing types in Australian cities in recent years. At the same time housing has become increasingly expensive, while low-density urban development has meant increasing social and economic costs for households in fringe suburbs. This paper explores current housing and location preferences of Adelaide residents. The findings suggest that home ownership and the single-storey detached dwelling are well entrenched preferences among residents, and that as yet, the personal costs of the linear spread of the city have not impacted significantly on housing and location preferences.     

Microwave-assisted pre-ionization experiments on GLAST-Ⅲ

GLAss Spherical Tokamak(GLAST-Ⅲ) is a spherical tokamak with an insulating vacuum vessel that has a unique single-passage capability for incident microwaves.In this work,electron cyclotron resonance heating(ECRH)-assisted plasma pre-ionization in GLAST-Ⅲ is explored for three radio-frequency(RF) polarizations(the O-,X-,and M-modes) at different toroidal-field(TF) strengths and filled gas pressures.The optimum hydrogen pressure is identified for efficient plasma pre-ionization.A comparison of the plasma pre-ionizations initiated by the O-,X-,and M-modes shows prominent differences in the breakdown time,location,and wave absorption.In the case of O-mode polarization,microwave absorption occurs for a relatively shorter duration,resulting in a bell-shaped electron-temperature(T_e) temporal profile.Microwave absorption is dominant in the case of the X-mode,leading to a broader T_e temporal profile.The M-mode discharge contains features of both the X-and O-modes.Efficient plasma pre-ionization is achieved in the X-mode polarization for the intermediate TF strengths(with a central toroidal magnetic field B_0=0.075 T).Traces of the electron-number density show a similar tendency,as revealed by T_e.These results suggest that the X-mode is the best candidate for efficient plasma pre-ionization at low filled gas pressures(~10~(-2) Pa) in small tokamaks.     

On designing an efficient control chart to monitor fraction nonconforming

Process control measures are mostly applied in production and manufacturing industries. The most important tool used in these disciplines is control chart. In manufacturing and production processes, when the quality characteristic of interest cannot be directly measured, it becomes essential to apply attribute control charts. To monitor fraction nonconforming of the output, quality practitioners mostly prefer p-chart. In this article, a new progressive mean (PM) control chart is being proposed for monitoring drift in proportion of nonconforming products. The design evaluations of the proposed chart are made and compared through different properties of run length distribution, such as average run length (ARL), standard deviation of run length (SDRL), and some percentile points. The performance of the proposed chart is assessed under zero-state and steady-state scenarios. The proposed PM chart is compared with p-chart, moving average (MA) chart, optimal CUSUM chart, modified exponentially weighted moving average (EWMA) chart, and runs rules p-charts for monitoring fraction nonconforming. The proposed chart spots efficiently sustained disturbances in the process as compared with their existing counterparts. Two illustrative examples are also provided; one from real-life application of nonconforming bearing and seal assemblies data and the other from simulated data for the implementation of PM chart.     

Vertical Handover Necessity Estimation Based on a New Dwell Time Prediction Model for Minimizing Unnecessary Handovers to a WLAN Cell

In this work, we devise a vertical handover necessity estimation (HNE) method to minimize unnecessary handovers for a mobile node (MN) entering a WLAN cell. The method relies on a new model for prediction of dwell time and computation of certain threshold values. By comparing the predicted dwell time with those thresholds, a MN is able to make decision whether it should perform handover to a WLAN cell, while keeping the probability of handover failure and probability of unnecessary handover within bounds. Simulation results obtained from Monte-Carlo experiments prove validity of the proposed model. We also compare this model with existing models for minimizing unnecessary handovers. We further enhance the analytical model by incorporating the throughput gain in HNE and show that this can further optimize handover decision in heterogenous networks.     

Effect of elementary and advanced glycation products of nisin on its preservative efficacy and digestibility

Nisin used as a natural preservative in variety of food systems was subjected to glycation at 95 °C in high molar concentration. The elementary glycation end products (EGEs) and the advanced glycated end products (AGEs) formed were tested as compared to non-glycation nisin (NN) for their antibacterial activity against some food spoilage organisms such as Staphylococcus aureus, Bacillus cereus, Micrococcus luteus, Clostridium botulinum and Lactobacillus sake. The extent of hydrolysis of EGEs and AGEs by trypsin was also compared with the (NN) as control. The results have illustrated that antibacterial activity of nisin was substantially affected by the process of glycation in case of all the five organisms selected for the study, suggesting that the glycation of nisin, whether invivo or invitro will adversely affect the preservation of foods. Moreover glycation also reduced the tryptic digestibility of EGEs by 5.2% and AGEs by 50.325% as compared to NN. The data indicated that amount of nisin, if added to carbohydrate consisting foods should be increased accordingly to claim the reported shelf life of the products and food labelling in such products needs cardinal modification. Although hydrolysis of glycated nisin by trypsin is slightly decreased, however; it will not produce any adverse effect on human digestion in view of the minute amount of nisin present in the food system.