Special issue on computing,communication and sensor network: CCSN,Puri, Odisha,India, 2014

Microsystem Technologies -     

An image-in-image communication scheme using secret sharing and M-ary spread spectrum watermarking

Microsystem Technologies - Secret image sharing is a means of secure transmission of images on an open network through meaningful share generation that reduces suspiciousness of conventional image...     

A new mechanistic model for liquid-liquid phase transfer catalysis: Reaction of benzyl chloride with aqueous ammonium sulfide

A new mechanistic model for reactions involving two liquid phases and a homogeneous phase transfer catalyst (PTC) has been developed based on extraction mechanism considering the equilibrium of catalyst and active catalysts at the interface. The proposed kinetic model considers thermodynamic framework based aqueous phase ionic equilibrium and the separate contributions of non-PTC and PTC-enhanced reactions towards the overall reactions. The developed model was then applied to an industrially important reaction of benzyl chloride with aqueous ammonium sulfide for synthesis of dibenzyl sulfide and benzyl mercaptan. The kinetic parameters of the developed model were estimated at different temperatures using an indigenously developed non-linear regression technique based on modified Levenberg-Marquardt algorithm. Sensitivity analysis was then performed under various experimental conditions using the estimated parameters and the results were compared with experimental observations. A good agreement was observed between experimental and calculated values with proper trends of the results.     

Toughening of epoxy resin with amine functional aniline acetaldehyde condensate

The diglycidyl ether of bisphenol-A (DGEBA) resin was modified with amine functional aniline acetaldehyde condensate (AFAAC) and cured with an ambient temperature curing agent triethylene tetramine. The resulting networks displayed significantly improved fracture toughness. The AFAAC was synthesized by the condensation reaction of aniline and acetaldehyde in the acid medium (pH 4) and characterized by FTIR and NMR spectroscopy, elemental analysis, viscosity measurements, and mole of primary and secondary amine analysis. The DGEBA and AFAAC were molecularly miscible but developed a two-phase microstructure upon network formation. Epoxy/AFAAC compositions were systematically varied to study the effect of AFAAC concentration on the impact, adhesive, tensile, and flexural properties of modified networks. The dynamic mechanical analysis and scanning electron microscopy studies showed two phase morphology in the cured networks, where AFAAC particles were dispersed. The AFAAC modified epoxy network was thermally stable up to around 280°C. POLYM. ENG. SCI., 47:1695–1702, 2007. © 2007 Society of Plastics Engineers     

Effect of Electrode Materials on Different EDM Aspects of Titanium Alloy

Silicon - Electro discharge machining (EDM) is extensively used in modern manufacturing industry because of its advantage over conventional machining method. Titanium alloys are the materials of...     

Microstructures,Martensitic Transformation,and Mechanical Behavior of Rapidly Solidified Ti-Ni-Hf and Ti-Ni-Si Shape Memory Alloys

In this work, the microstructure and mechanical properties of rapidly solidified Ti_50?x/2Ni_50?x/2Hf _x (x = 0, 2, 4, 6, 8, 10, and 12 at.%) and Ti_50?y/2Ni_50?y/2Si _y (y = 1, 2, 3, 5, 7, and 10 at.%) shape memory alloys (SMAs) were investigated. The sequence of the phase formation and transformations in dependence on the chemical composition is established. Rapidly solidified Ti-Ni-Hf or Ti-Ni-Si SMAs are found to show relatively high yield strength and large ductility for specific Hf or Si concentrations, which is due to the gradual disappearance of the phase transformation from austenite to twinned martensite and the predominance of the phase transformation from twinned martensite to detwinned martensite during deformation as well as to the refinement of dendrites and the precipitation of brittle intermetallic compounds.     

Control of thermo reversible gelation of methylcellulose using polyethylene glycol and sodium chloride for sustained delivery of ophthalmic drug

The effect of molecular weight of polyethyleneglycol (PEG) and sodium chloride (NaCl) on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ophthalmic drug. The gelation temperature of 1% MC was 60 ± 0.40°C. It was found that the gelation temperature of MC was reduced with the addition of 10% PEG and extent of reduction of gelation temperature was depended on the molecular weight of PEG at same PEG concentration of 10%. The gelation temperature of MC was reduced by 10.4 to 5.9°C with the increasing molecular weight of PEG starting from 400 to 20,000 (M_n ) depending on the method of determination of gelation temperature. To reduce the gelation temperature of MC close to physiological temperature (37°C), 6% NaCl was added in the different MC‐PEG combinations containing different molecular weight of PEG. It was observed that the drug release time increased from 5 to 8 h with the increase in molecular weight of PEG from 400 to 20,000 (M_n ) and this was due to the maximum viscosity and gel strength of MC‐PEG20000‐NaCl ternary combination. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Hydrotreating of Maya Crude Oil: II. Generalized Relationship between Hydrogenolysis and HDAs

Studies of hydrodeasphaltenization (HDAs) and hydrodemetallization (HDM) of Maya heavy crude oil at temperature of 380°C and pressure of 5.4 MPa have been carried out in a high pressure microreactor. Different pore diameter alumina CoMo-supported catalysts were prepared and their catalytic effect is estimated. The fresh and spent catalysts were characterized by textural properties; and the average pore diameter of a fresh catalyst was found to be proportional to the HDM and HDA conversions. The hydrogen elemental analysis of reactant and products indicated that asphaltene conversion is a combination of cracking and hydrogenation (HYD), since HDM correlated well with HDAs, which is due to the complex nature of both molecules (asphaltene and metals).