Organogel Formation of Soybean Oil with Waxes

Many waxes including plant waxes and animal waxes were evaluated for the gelation ability toward soybean oil (SBO) and compared with hydrogenated vegetable oils, petroleum waxes and commercial non-edible gelling agents to understand factors affecting the gelation ability of a gelator. Sunflower wax (SW) showed the most promising results and all SW samples from three different suppliers could make a gel with concentrations as low as 0.5 wt%. Candelilla wax and rice bran wax also showed good gelation properties, which, however, varied with different suppliers. Gelation ability of a wax is significantly dependant on its purity and detailed composition. A wax ester with longer alkyl chains has significantly better gelation ability toward SBO than that with shorter alkyl chains indicating that the chain length of a component in a wax such as wax ester is an important factor for gelation ability. The SW–SBO organogel showed increased melting point with increased SW content, showing the melting point range from about 47 to 65 °C with 0.5–10 wt% SW. The effects of cooling rate on crystal size and firmness of a gel were investigated. The dependence of firmness on cooling rate was so significant that the desired texture of an organogel could be achieved by controlling the cooling rate in addition to controlling the amount of gelling agent. This research reveals that a small amount of food grade plant waxes including SW may replace a large amount of the hardstock containing trans-fat or saturated fat.     

New Insights into the Electrochemical Behavior of Hematite (<Emphasis Type="Italic">α</Emphasis>-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>) Microparticles in Strong Aqueous Basic Electrolyte: Formation of Metallic Iron

A detailed electrochemical study of cubic α-Fe₂O₃ microparticles has been carried out in strong aqueous LiOH electrolyte. The α-Fe₂O₃ was synthesized hydrothermally and investigated in the form of an electrochemical cell using an alkaline solution, ‘α-Fe₂O₃|LiOH (saturated), ZnSO₄ (1 M)|Zn’. In this cell, the α-Fe₂O₃ cathode showed a reversible capacity of ca 220 mAh/g within cut-off voltages of 0 and 1.5 V under the constant current of 0.3 mA. The electrochemical performance was attributed to the reversible formation of both proton and lithium intercalation products (FeOOH and LiFeO₂) detected in the cathode material. Interestingly, at a lower discharge current of 0.1 mA, some of the hematite phase was reduced to metallic iron after yielding 336 mAh/g. The various possible electro-reduction reactions, which have direct electro-hydrometallurgical implications, are analyzed and discussed.     

Influence of carbon nanotube dispersion on the mechanical properties of phenolic resin composites

Despite the much touted mechanical properties of carbon nanotubes, composites reinforced with nanotubes have failed to achieve mechanical properties which rival those present in conventional fiber reinforced polymer composites. This article describes an attempt to bridge this gap. Multi‐walled carbon nanotubes (MWCNT) were synthesized using a chemical vapor deposition method and were dispersed in phenolic resin by both the wet and dry dispersion techniques before molding into composite bars (50 × 5 × 3 mm³). Although no improvement in the mechanical properties of the MWCNT/phenolic composites was observed over the neat resin value when wet mixing dispersion was employed, an improvement of nearly 158% (160 MPa as compared with 62 MPa for neat resin) was achieved in 5 vol% MWCNT containing phenolic resin prepared by the dry mixing. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Studies on effect of nanoclay on the properties of thermally sprayable EVA and EVAI coatings

Dispersion of nanoclay (NC) in polymer blend system is governed by the sequence of addition of different ingredients. In the present work nanoclay was added in different sequences to blend composition such as ethylene vinyl acetate (EVA)/low density polyethylene (LDPE) and ethylene vinyl alcohol (EVAl)/LDPE in internal mixer to get nanocomposite. It was found that sequential addition of individual polymers and nanoclay influenced mechanical properties of resulting composites. Blending sequence of PE/NC/EVA and PE/NC/EVAl gave best mechanical properties. After optimization of addition sequence, concentration of nanoclay was varied from 1 to 8% by weight in the polymer blend. The resulting composites were evaluated in terms of their mechanical properties, dispersion characteristics (XRD), water vapor transmission rate (WVTR) and water absorption (Wa). Nanocomposite containing EVA/LDPE blend with 4% nanoclay showed optimum properties. The optimized composition was applied on grit blasted mild steel specimens by flame spray technique. The coated specimens were evaluated for adhesion strength, abrasion resistance and resistance to corrosion properties.     

Induction of chemical and moisture resistance in Saccharum spontaneum L fiber through graft copolymerization with methyl methacrylate and study of morphological changes

In this article, morphological modification of Saccharum spontaneum L, a natural fiber through graft copolymerization with methylmethacrylate using ferrous ammonium sulfate—potassium per sulfate redox initiator has been reported. Different reaction parameters such as reaction temperature, time, initiator molar ratio, monomer concentration, pH and solvent were optimized to get maximum graft yield (144%). The graft copolymers thus formed were characterized by Fourier transform infrared, scanning electron microscopy, X‐ray diffraction and thermogravimetric, differential thermal analysis, and differential thermogravimetric techniques. Graft copolymer has been found to be more moisture resistant and also showed higher chemical and thermal resistance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

A Programmable Phased Array with Time-Delay Units and its Applications

In this paper, a phased array antenna schematic using true time delays is proposed and suitable time-delays are inserted by switching ON/OFF the RF switches. Using this concept, one can generate SUM pattern, DIFFERENCE pattern, as well as a combination of these two. It is shown that SUM-DIFFERENCE pattern has interesting applications in radar, namely, calibration of beam pointing accuracy and blind speed elimination in a delay line cancellation method. The proposed method can also be formatted to requirements of conical scan as well as shaped beam generation. The proposed method is validated using existing knowledge.     

Experimental study of distribution of energy during EDM process for utilization in thermal models

Electrical discharge machining (EDM) has steadily gained importance over the years because of its ability to cut and shape a wide variety of materials and complicated shapes with high accuracy. The effectiveness of the EDM process is evaluated in terms of the material removal rate, relative wear ratio and the surface roughness of the work piece. The input discharge energy during this process is distributed to various components of the process, which further influences the material removal rate and other machining characteristics like surface roughness. Since during this process the electrical energy is converted into heat energy, hence the theoretical modeling of this process is based upon the heat transfer equations and in all existing thermal models the fraction of the energy transferred to the workpiece, is one of the important parameters. The accurate prediction of the fraction of energy effectively transferred to the workpiece will help to reduce the errors of the thermal models. In this study experiments have been performed to study the percentage fraction of energy transferred to the workpiece utilizing heat transfer equations, at different EDM parameters. This study also relates the optimum parameters with the optimum utilization of input discharge energy and hence will help to improve the technological performance of this process.