Scalable and portable implementation of the fast multipole method on parallel computers

A scalable and portable Fortran code is developed to calculate Coulomb interaction potentials of charged particles on parallel computers, based on the fast multipole method. The code has a unique feature to calculate microscopic stress tensors due to the Coulomb interactions, which is useful in constant-pressure simulations and local stress analyses. The code is applicable to various boundary conditions, including periodic boundary conditions in two and three dimensions, corresponding to slab and bulk systems, respectively. Numerical accuracy of the code is tested through comparison of its results with those obtained by the Ewald summation method and by direct calculations. Scalability tests show the parallel efficiency of 0.98 for 512 million charged particles on 512 IBM SP3 processors. The timing results on IBM SP3 are also compared with those on IBM SP4.     

Piezoelectric Energy Harvesting under High Pre-Stressed Cyclic Vibrations

Cymbal transducers have been found as a promising structure for piezoelectric energy harvesting under high force (∼ 100 N) at cyclic conditions (∼ 100–200 Hz). The thicker steel cap enhances the endurance of the ceramic to sustain higher ac loads along with stress amplification. This study reports the performance of the cymbal transducer under ac force of 70 N with a pre-stress load of 67 N at 100 Hz frequency. At this frequency and force level, 52 mW power was generated from a cymbal measured across a 400 kΩ resistor. The ceramic diameter was fixed at 29 mm and various thicknesses were experimented to optimize the performance. The results showed that the PZT ceramic of 1 mm thickness provided the highest power output with 0.4 mm endcap. In order to accommodate such high dynamic pressure the transducer and cap materials were modified and it was found that the higher piezoelectric voltage constant ceramic provided the higher output power. Electrical output power as a function of applied ac stress magnitude was also computed using FEM analysis and the results were found to be functionally coherent with experiment. This study clearly demonstrated the feasibility of using piezoelectric transducers for harvesting energy from high magnitude vibration sources such as automobile.     

The Determination of Low-Level Water in Transdermal Dosage Forms as Tyvek Laminates with an Evaporator Oven

An assay of water in adhesive monolithic transdermal drug dosage forms ('patches'), using lamination to Tyvek, and gaseous extraction in an evaporator oven into a Karl Fischer titrator, is described. The method is simple, linear, accurate, specific and more sensitive than alternatives.     

Fatty acid composition of muscle fat and enzymes of storage lipid synthesis in whole muscle from beef cattle

Enhanced intramuscular fat content (i.e., marbling) in beef is a desirable trait, which can result in increased product value. This study was undertaken with the aim of revealing biochemical factors associated with the marbling trait in beef cattle. Samples of longissimus lumborum (LL) and pars costalis diaphragmatis (PCD) were taken from a group of intact crossbred males and females at slaughter, lipids extracted, and the resulting FAME examined for relationships with marbling fat deposition. For LL, significant associations were found between degree of marbling and myristic (14∶0, r=0.55, P<0.01), palmitic (16∶0, r=0.80 P<0.001), stearic (18∶0, r=−0.58, P<0.01), and oleic (18∶1c-9, r=0.79, P<0.001) acids. For PCD, significant relationships were found between marbling and palmitic (r=0.71, P<0.001) and oleic (r=0.74, P<0.001) acids. Microsomal fractions prepared from PCD muscle were assayed for diacylglycerol acyltransferase (DGAT), lysophosphatidic acid acyltransferase (LPAAT), and phosphatidic acid phosphatase-1 (PAP-1) activity, and the results examined for relationships with degree of intramuscular fat deposition. None of the enzyme activities from PCD displayed an association with marbling fat content, but DGAT specific activity showed significant positive associations with LPAAT (r=0.54, P<0.01), total PAP (r=0.66, P<0.001), and PAP-1 (r=0.63, P<0.01) specific activities. The results on FA compositions of whole muscle tissues provide insight into possible enzyme action associated with the production of specific FA. The increased proportion of oleic acid associated with enhanced lipid content of whole muscle is noteworthy given the known health benefits of this FA.     

Activation of ethyl acetate over metal substituted MCM-41: application to alkylation and acylation

Al-MCM-41, Fe,Al-MCM-41 and Zn,Al-MCM-41 materials with different silicon to metal ratios were synthesized hydrothermally and characterized by XRD, BET, FT-IR, Acidity measurement by pyridine adsorbed FT-IR spectroscopy, ²⁹Si and ²⁷Al MAS NMR and ESR techniques. The orderly arrangement of mesoporous materials was clearly revealed from the XRD patterns. ²⁹Si and ²⁷Al MAS NMR established the co-ordination environment of silicon and aluminium. Electron paramagnetic resonance (EPR) study confirmed the co-ordination environment of Fe in Fe,Al-MCM-41 framework. The catalytic activity of these materials was evaluated in the vapour phase alkylation and acylation of ethylbenzene with ethyl acetate in the temperature range between 250 and 400 °C. The products were found to be 1,3-diethylbenzene (1,3-DEB), 1,4-diethylbenzene (1,4-DEB), 1,2-diethylbenzene (1,2-DEB), 4-ethylacetophenone (4-EAP) and acetophenone (AP). The reaction products revealed that activation of ethyl acetate is a convenient route for both alkylation and acylation reactions. The order of the catalysts activity for the reaction is found to be Fe,Al-MCM-41 (50) > Fe,Al-MCM-41 (100) > Zn,Al-MCM-41 (50) > Zn,Al-MCM-41 (100) > Al-MCM-41 (50) > Al-MCM-41 (100). In addition to the density of acid sites, the strength of acid sites is also important for this reaction. The effects of temperature, feed ratio, WHSV and time on stream were also examined and the results are discussed.     

Selective ion-exchange in MAPO-36 and its application in toluene disproportionation

MAPO-36 was synthesized hydrothermally by isomorphic substitution of Mg²⁺ in the framework of AlPO-36 and ion-exchanged with Fe³⁺, Zn²⁺, La³⁺ and Ce³⁺ by wet method. The materials were characterized by XRD, TGA, TPD (ammonia) and SEM-EDX. XRD revealed absence of structural degradation after ion-exchange. TPD (ammonia) showed selective ion-exchange of strong acid sites in ion-exchanged MAPO-36. The weight loss around 550 °C in TGA for Fe, La and CeMAPO-36 suggested conversion of M(OH)₂⁺ to MO⁺. Toluene disproportionation was carried over all catalysts in which diphenyl methane derivative was suggested to be the principle intermediate in the formation of p-xylene and other products. The time on stream study showed exclusive formation of p-xylene after 6 h.     

Ozone based food preservation: a promising green technology for enhanced food safety

Extending shelf life of food products is a major concern of the producers, and the food industry requires ‘greener’ alternatives to the current technologies. Ozone-based food preservation may suit this niche. Ozone is an attractive alternative preservative that food industry needs due to its properties such as quick decomposition and little residual effect during food preservation. Ozone is the strongest molecule available for the disinfection of water and is second only to elemental fluorine in oxidizing power. Ozone is being used in the food industry in various applications such as decontamination of water and equipment surfaces. Several researchers have focused on the application of ozone to inactivate microorganisms on fresh produce, like fruits, vegetables, meat, poultry, fish, and eggs, and dry produce, such as cereals, pulses, and spices. This review comprehensively analyses appropriate ozone concentrations and exposure times and discusses various factors that affect the quality and safety of food products during ozonation.     

Pressurized ultrasonic production of biodiesel from Jatropha oil: optimization and energy analysis

The present study deals with the development of a biodiesel production reactor based on pressurized ultrasonic cavitation technique. Transesterification of Jatropha oil takes place by passing low-frequency ultrasonic irradiation in the reaction mixture flowing at pressurized conditions in the sonochemical reactor. Reaction variables such as reaction time, molar ratio, catalyst concentration, and pressure of the reaction mixture were investigated to find the optimal parameters for biodiesel production. The energy requirement decreases with increase in pressure. Very low value of Specific Energy Consumption (0.018 kWh/kg) and significantly high value of Energy Use Index (598.83) are obtained when the pressure of reaction mixture is 15 bar. Increasing the pressure thereafter, leads to nominal gains. Ultrasonic irradiation at high-pressure condition has an additional advantage of rapid reaction and lower requirement of alcohol to oil molar ratio and catalyst concentration. Fifteen bar pressure is optimal for biodiesel production.     

Hydrothermal synthesis of α-SnWO4: Application to lithium-ion battery and photocatalytic activity

The high capacity anode material is required to replace the most commonly used anode - graphite to keep up the global demand to achieve the goal. Multi-metal oxide has gained keen attention for its higher theoretical capacity and relatively stable than a single metal oxide. α-SnWO₄ has a theoretical capacity of 850 mAh g^?1 which is greater than graphite (372 mAh g^?1). α-SnWO₄ has been synthesized through low-temperature hydrothermal method using tin chloride and sodium tungstate as a precursor in acidic medium (succinic acid) at 200 °C for 12 h. The obtained product has been characterized using various analytical tools such as XRD, FT-IR, UV-DRS, BET, PL, SEM, and HR-TEM. XRD analysis shows the orthorhombic phase with a crystallite size of ~25 nm α-SnWO₄has been examined as an electrode material for Li-ion battery (LIB) and displays an initial discharge capacity of 985 mAh g^?1. Columbic efficiency close to 100% has been observed for 100 cycles. The stability of the electrode material was studied at different C-rates. Band-gap calculated using UV-DRS (Eg = 1.9 eV) shows that α-SnWO₄ is a good candidate for photocatalytic degradation. Results of the photocatalytic experiment using methylene blue (MB) as a model pollutant in an aqueous medium shows good results. The above applications show that α-SnWO₄ is multifunctional materials for diverse applications.     

Characterization of Waste and Reclaimed Green Sand Used in Foundry Processing

Silicon - The aim of this study is to discuss the importance of characterization of green, waste green and reclaimed sand. The transformations and changes which take place in the green sand, are...