Synthesis of a novel efficient antioxidant for use in lubes and biodiesel

A novel phenolic ester Bz-3-tBz was synthesized by reaction between 1,3,5-benzenetricarboxylic acid chloride and 3,5-di-tert-butyl-4-hydroxybenyl alcohol using N,N’-dimethylacetamide solvent and N,N’-dimethylaminopyridine as catalyst. The additive Bz-3-tBz was characterized by CHN, FT-IR, NMR and TG. The Bz-3-tBz was then evaluated as antioxidant additive in polyol by the rotatory bomb oxidation test (RBOT) as per ASTM D2272. The RBOT time for the blank sample containing only polyol base was observed to be 6 min 43 sec. It was observed that Bz-3-tBz in 3000 ppm concentration enhanced the RBOT time to the 15 min 46 sec. It was a significant increase of 2.35 times. The oxidation stability of biodiesel was also found to be increased when Bz-3-tBz was added in to it. The value of induction time determined by the Rancimat test for the biodiesel at 130°C was 0.60 h which was increased to 3.14 h at 2000 ppm Bz-3-tBz concentration.     

Broadcasting with Controlled Redundancy and Improved Localization in Wireless Sensor Networks

Wireless sensor networks （WSNs） consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last few years. There are many challenging tasks in the network, including redundancy control and sensor node localization that mainly depend on broadcasting. In this paper, we propose a broadcasting algorithm to control redundancy and improve localization （BACRIL） in WSNs. The proposed algorithm incorporates the benefits of the gossip protocol for optimizing message broadcasting within the network. Simulation results show a controlled level of redundancy, which is up to 57.6% if the number of sensor nodes deployed in a 500 m×500 m area are increased from 50 to 500.     

Effect of cerium oxide nanoparticles coating on the electrodes of benthic microbial fuel cell

Benthic microbial fuel cell is a power source for low-power devices. For enhancement of power, Cerium oxide (CeO₂) nanoparticles (NPs) were coated on anode and cathode electrodes and compared separately. CeO₂ NPs were synthesized by hydrothermal method and characterized by Dynamic light scattering. Polyvinylidene fluoride and graphite powder were used as a conductive matrix for binding CeO₂ NPs. Coated electrodes were characterized by physical and electrochemical analysis. Maximum power densities generated by CeO₂ coated cathode and anode were 60 and 43 mW/m³ respectively; whereas conductive matrix only produced 14 mW/m³. Results demonstrated that CeO₂ at cathode performed better than at anode. NPs show their effectiveness as an oxygen reduction reaction catalyst in the sea water.     

An experimental study on pool boiling of milk

This research paper reports the results for convective heat transfer coefficient and nucleate boiling heat flux for pool boiling of milk during khoa making. Various indoor experiments were conducted for different heat flux inputs varying from 9638.55 to 14457.83 W/m². Experimental data obtained for pool boiling of milk were analyzed by using the Rohsenow correlation with the help of simple linear regression analysis. The convective heat transfer coefficients were estimated in the range of 334.48 to 837.78 W/m² °C for the given heat inputs. The results for heat flux were found to be varying from 3344.8 to 8377.8 W/m² at 10 °C excess temperature of the aluminum pot surface above the saturation temperature of the milk. The experimental errors in terms of percent uncertainty were also calculated. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/htj.20336     

Reliability‐based robust design optimization: A multi‐objective framework using hybrid quality loss function

In this globally competitive business environment, design engineers are constantly striving to establish new and effective tools and techniques to ensure a robust and reliable product design. Robust design (RD) and reliability‐based design approaches have shown the potential to deal with variability in the life cycle of a product. This paper explores the possibilities of combining both approaches into a single model and proposes a hybrid quality loss function‐based multi‐objective optimization model. The model is unique because it uses a hybrid form of quality loss‐based objective function that is defined in terms of desirable as well as undesirable deviations to obtain efficient design points with minimum quality loss. The proposed approach attempts to optimize the product design by addressing quality loss, variability, and life‐cycle issues simultaneously by combining both reliability‐based and RD approaches into a single model with various customer aspirations. The application of the approach is demonstrated using a leaf spring design example. Copyright © 2009 John Wiley & Sons, Ltd.     

Dielectric properties of CaCu3Ti4−xCoxO12 (x = 0.10, 0.20, and 0.30) synthesized by semi-wet route

Undoped CaCu₃Ti₄O₁₂ and cobalt doped CaCu₃Ti_4−xCo_xO₁₂ (CCTCO) with x = 0.10, 0.20 and 0.30 were prepared by semi-wet route for the first time using solid TiO₂ powder and metal nitrate solutions. XRD analysis confirmed the formation of single-phase material in the samples sintered at 900 °C for 6 h. Structure does not change on doping with cobalt and it remains cubic in all the three compositions studied. Lattice parameter increases slightly with cobalt doping. SEM micrographs of the CaCu₃Ti_4−xCo_xO₁₂ samples show that the grain size is in the range of 2–8 μm for these samples. EDX studies show the percentage of elements along with the grain and grain boundary, which confirm the rich phase of copper oxide at grain boundaries. Dielectric properties have been measured as a function of temperature and frequency.     

Preparation and characterization of cordierite filled PTFE laminates for microwave substrate applications

Phase pure cordierite (2MgO · 2Al₂O₃ · 5SiO₂) powder was prepared through solid state ceramic route. Silane coated cordierite powder was filled in the PTFE matrix through SMECH process comprising of sigma mixing, extrusion, calendering, followed by hot pressing, to fabricate flexible microwave substrates. Filling fraction of cordierite in the PTFE matrix was varied from 10 to 70 wt% and its effects on density, dielectric properties, coefficient of thermal expansion and water absorption were investigated. The morphology and filler distribution of the filled composite were studied by SEM. Waveguide cavity perturbation technique was employed to measure the dielectric properties of the composites at X-band (8.2–12.4 GHz). Dielectric constant and loss tangent were found increasing with filler loading from 10 wt% (ε _r′ = 2.17, tan δ = 0.0007) to 60 wt% (ε _r′ = 3.17, tan δ = 0.0034).     

Application of metamaterials for performance enhancement of planar antennas: A review

Metamaterials are assemblies of metallic and/or dielectric materials with properties that are not readily found in naturally existing materials. Hence, metamaterial structures are commonly loaded on/near the patch, embedded in the substrate, loaded/etched from the ground plane or placed as a superstrate layer for enhancing bandwidth and gain, and size miniaturization of conventional patch antennas. The demand for wide bandwidth, high gain, and compact antennas is highly contemplated in recent wireless communication research studies. Despite their lightweight, ease of fabrication, low profile, and simplicity for integration, patch antennas have performance limitations as result of their narrow bandwidth, lower gain, larger size, and lower power handling capacity. To address these problems, metamaterial‐based antennas have gained massive interest. There exist inadequate literatures about review of current state of extensive study reports on metamaterial application for patch antenna performance enhancement. Thus, this paper has reviewed and discussed latest research works on metamaterial applications for performance enhancement of planar patch antennas.