Enhancing the efficiency of absorption refrigeration cycle by ‘seeding’ nanoparticles directly in the working fluid

The fossil fuel-driven electricity grid supplies space cooling especially in tropical/temperate climate regions. The timing of the peak load closely coincides with the peak of available solar irradiance. Therefore, solar-driven space cooling can reduce the peak loads in a smart grid. Solar-powered, direct absorption refrigeration cycles fit well. The efficiency of this cycle can be enhanced through the use of new, engineered materials. This study analyses a model of ammonia–water based absorption refrigeration cycle in which nanoparticles are directly ‘seeded’ in the working fluid itself. The model has been tested at various locations in India.     

Load balancing and data placement for multi-tiered database systems

A materialized view or Materialized Query Table (MQT) is an auxiliary table with precomputed data that can be used to significantly improve the performance of a database query. A Materialized Query Table Advisor (MQTA) is often used to recommend and create MQTs. The state-of-the-art MQTA works in a standalone database server where MQTs are placed on the same server as that in which the base tables are located. The MQTA does not apply to a federated or scaleout scenario in which MQTs need to be placed on other servers close to applications (i.e. a frontend database server) for offloading the workload on the backend database server. In this paper, we propose a Data Placement Advisor (DPA) and load balancing strategies for multi-tiered database systems. Built on top of the MQTA, DPA recommends MQTs and advises placement strategies for minimizing the response time for a query workload. To demonstrate the benefit of the data placement advising, we implemented a prototype of DPA that works with the MQTA in the IBM^® DB2^® Universal Database™ (DB2 UDB) and the IBM WebSphere^® Information Integrator (WebSphere II). The evaluation results showed substantial improvements of workload response times when MQTs are intelligently recommended and placed on a frontend database server subject to space and load characteristics for TPC-H and OLAP type workloads.     

Synthesis of self-organized mixed oxide nanotubes by sonoelectrochemical anodization of Ti-8Mn alloy

Self ordered arrays of titanium manganese mixed oxide nanotubes were prepared by anodization of Ti8Mn alloy (UNS R56080) under ultrasonication in diluted ethylene glycol containing fluoride. The dimensions of the nanotubes (diameter: 20-100 nm and length: 0.5-2.0 μm) could be tuned by changing the synthesis parameters. The as-anodized nanotubes showed a stoichiometry of (Ti,Mn)O₂. Upon annealing at 500 °C in oxygen atmosphere, the nanotubes contained a mixture of anatase + rutile phases of TiO₂ and Mn₂O₃. The composition of the oxide nanotubes was influenced by the chemistry of the phases present in the alloy. More manganese content was observed in the oxide formed on the β-phase than in the oxide layer of α-phase. Anodization in the ultrasonic field increased the kinetics of nanotubular oxide formation and resulted in homogeneous ordering of the nanotubular arrays as compared to the anodization by conventional stirring in the fluoride containing ethylene glycol solution. Whereas, anodization in aqueous acidified fluoride solutions resulted in severe attack of the β-phase and did not show presence of nanotubular oxide structure.     

A neural network approach for data masking

In this letter we present a neural network based data masking solution, in which the database information remains internally consistent yet is not inadvertently exposed in an interpretable state. The system differs from the classic data masking in the sense that it can understand the semantics of the original data and mask it using a neural network which is a priori trained by some rules. Our adaptive data masking (ADM) concentrates on data masking techniques such as shuffling, substitution, masking and number variance in an intelligent fashion with the help of adaptive neural network. The very nature of being adaptive makes data masking easier and content agnostic, and thus finds place in various vertical domains and systems.     

A statistical analysis of rotary friction welding of steel with varying carbon in workpieces

Laser drilling is increasingly becoming the method of choice for precision drilling for variety of components. However, a number of defects such as spatter, recast, heat-affected zone (HAZ), and taper limit the application. Elimination of these defects is the subject of intense research. This paper presents a grey relational optimization approach for the determination of the optimum process parameters which minimize the HAZ and hole circularity and maximize material removal rate in a Pulsed Nd:YAG laser micro-drilling in high carbon steel within existing resources. The input process parameters considered are pulse width, number of pulses, assist gas (oxygen) flow rate, and its supply pressure. A higher resolution-based L₂₅ orthogonal array has been used for conducting the experiments. The designed experimental results are used in grey relational analysis and the weights of the quality characteristics are determined optimizing the parameters. On the basis of optimization results, it has been found that the optimal parameter level gives a small HAZ, fine hole, and maximum material removal rate. Subsequently, the results are also verified and found appropriate by running confirmation tests.     

<Emphasis Type="Italic">Trans</Emphasis>–<Emphasis Type="Italic">trans</Emphasis> Conjugated Linoleic Acid Enriched Soybean Oil Reduces Fatty Liver and Lowers Serum Cholesterol in Obese Zucker Rats

Conjugated linoleic acid (CLA) is a collection of octadecadienoic fatty acids that have been shown to possess numerous health benefits. The CLA used in our study was produced by the photoisomerization of soybean oil and consists of about 20% CLA; this CLA consists of 75% trans–trans (a mixture of t8,t10; t9,t11; t10,t12) isomers. This method could be readily used to increase the CLA content of all soybean oil used as a food ingredient. The objective of this study was to determine the effects of trans–trans CLA-rich soy oil, fed as a dietary supplement, on body composition, dyslipidemia, hepatic steatosis, and markers of glucose control and liver function of obese fa/fa Zucker rats. The trans–trans CLA-rich soy oil lowered the serum cholesterol and low density lipoprotein–cholesterol levels by 41 and 50%, respectively, when compared to obese controls. Trans–trans CLA-rich soy oil supplementation also lowered the liver lipid content significantly (P < 0.05) with a concomitant decrease in the liver weight in the obese rats. In addition, glycated hemoglobin values were improved in the group receiving CLA-enriched soybean oil in comparison to the obese control. PPAR-γ expression in white adipose tissue was unchanged. In conclusion, trans–trans CLA-rich soy oil was effective in lowering total liver lipids and serum cholesterol.     

Decomposition of 2‐chlorophenol, 4‐chlorophenol and 2,4,6‐trichlorophenol by catalytic oxidation over cobalt and nickel impregnated SBA‐15

This work describes the use of Co(II) and Ni(II) impregnated SBA‐15 as catalysts for the oxidative degradation of a few persistent chlorinated phenols in an aqueous medium: 2‐chlorophenol (2‐CP), 4‐chlorophenol (4‐CP) and 2,4,6‐trichlorophenol (2,4,6‐TCP). The catalysts were characterised in terms of their crystallographic features, surface topography, functional groups, thermal stability, etc. The oxidation reactions were carried out using the reaction time, concentration of chlorophenol, amount of catalyst and pH of the reaction mixture as the process variables with or without hydrogen peroxide as the chemical oxidising agent. The conversion achieved with Co/SBA‐15 for 2‐CP, 4‐CP and 2,4,6‐TCP was respectively 84.7%, 78.4% and 64.8% with H₂O₂ and 86.3%, 80.2% and 70.3% in the absence of H₂O₂. The conversion with Ni/SBA‐15 also at 353 K for 2‐CP, 4‐CP and 2,4,6‐TCP was, respectively, 82.3%, 81.9% and 64.0% at 5 h with H₂O₂ and 89.5%, 82.9% and 65.6% without H₂O₂. The reactions followed pseudo‐first‐order kinetics. The leachability study indicated that the catalysts release very little Co and Ni to water. Therefore, the possibility of water contamination through metal leaching was almost negligible. Oxidative degradation was confirmed by measuring the total organic carbon. © 2012 Canadian Society for Chemical Engineering     

Crosslinking diversity on network morphology,template binding,and template transport of molecularly imprinted polymers prepared via living radical polymerization

The objective of this work is to study the effects of altering the chain building blocks and the reaction on template binding and transport parameters of imprinted polymer gels. The characterization of imprinted poly(diethylaminoethylmethacrylate‐co‐hydroxyethylmethacrylate‐co‐polyethyleneglycol(n)dimethacrylate) polymer gels prepared via free (FRP) or living (LRP) radical polymerization with varying crosslinking monomer lengths (number of ethylene glycol repeat units of 1, ～4.5, ～9) and concentrations (1, 5, 10, 50%) is presented. All imprinted networks prepared via LRP exhibited significantly higher template binding affinities and capacities as well as significantly lower template diffusion coefficients compared to those prepared via FRP. Synthesizing imprinted polymers via LRP results in much smaller and relatively constant dispersities of polymer chains compared to imprinted polymers prepared via FRP. Therefore, LRP has a profound structural effect on the imprinted polymer network leading to increased homogeneity in the mesh structure which enhances the molecular imprinting effect. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3588–3599, 2013     

Effect of SBS Content on Low Temperature Impact Strength,Morphology and Rheology of PP-cp/SBS Blends

Izod impact strength of PP impact copolymer/Styrene-Butadiene-Styrene blends were evaluated at varied sub-zero temperatures and demonstrated 12 times enhancement in impact strength of 40% SBS containing blend over pure PP-cp at ?40°C. SBS content played a vital role in morphology development as it changes from droplet morphology to elongated ellipsoid to a seemingly networked structure leading towards different fracture mechanisms. Rheological properties of blends evaluated on capillary rheometer showed pseudoplastic behavior at varied shear rates (50 ? 10⁴ s^?1) at 220°C and good agreement between experimental shear viscosity and theoretical values as per log additivity principle at high shear rates.