ANN based prediction model for fatigue crack growth in DP steel

An artificial neural network (ANN)-based model was developed to analyse high-cycle fatigue crack growth rates (d a /d N ) as a function of stress intensity ranges (Δ K ) for dual phase (DP) steel. The training data consisted of d a /d N at Δ K ranges between 5 and 16 MPa √ for DP steel with martensite contents in the range 32 to 76%. The ANN back-propagation model with Gaussian activation function exhibited excellent agreement with the experimental results. The fatigue crack growth rate predictions were made to demonstrate its practical significance in a given real-life situation. Because of the wide range of data points used during training of the model, it will provide a useful predictor for fatigue crack growth in DP steels.     

Conversion of pencil graphite to graphene/polypyrrole nanofiber composite electrodes and its doping effect on the supercapacitive properties

Graphene platelets were synthesized from pencil flake graphite and commercial graphite by chemical method. The chemical method involved modified Hummer's method to synthesize graphene oxide (GO) and the use of hydrazine monohydrate to reduce GO to reduced graphene oxide (rGO). rGO were further reduced using rapid microwave treatment in presence of little amount of hydrazine monohydrate to graphene platelets. Chemically modified graphene/polypyrrole (PPy) nanofiber composites were prepared by in situ anodic electropolymerization of pyrrole monomer in the presence of graphene on stainless steel substrate. The morphology, composition, and electronic structure of the composites together with PPy fibers, graphene oxide (GO), rGO, and graphene were characterized using X‐ray diffraction (XRD), laser‐Raman, and scanning electron microscopic (SEM) methods. From SEM, it was observed that chemically modified graphene formed as a uniform nanocomposite with the PPy fibers absorbed on the graphene surface and/or filled between the graphene sheets. Such uniform structure together with the observed high conductivities afforded high specific capacitance and good cycling stability during the charge–discharge process when used as supercapacitor electrodes. A specific capacitance of supercapacitor was as high as 304 F g^?1 at a current density of 2 mA cm^?1 was achieved over a PPy‐doped graphene composite. POLYM. ENG. SCI., 55:2118–2126, 2015. © 2014 Society of Plastics Engineers     

Chemical and analytical screening of some edible mushrooms

Fractionation of extracts of the edible mushroom, Volvariella volvacea, led to the isolation of two heterocyclic carboxylic acids, namely pyridine-3-carboxylic acid [nicotinic acid, (5)] and pyrazole-3(5)-carboxylic acid (6) and the four steroidal metabolites ergosterol (1), 5-dihydroergosterol (2), ergosterol peroxide (3), cerevisterol (4). Significantly, compound (6) was identified for the first time, to our knowledge, in the mushroom kingdom and is of taxonomic significance. Compounds (2–4) were isolated for the first time from the Volvariella genus. In view of the structural similarity of compound (6) to pyrazole-3-carboxylic acids, which act as agonists for nicotinic acid receptors, the levels of compounds (5) and (6) were estimated for the first time using HPTLC in V. volvacea and two other edible mushrooms, namely Agaricus bisporus and Calocybe indica. Significant levels of compound (5) were found in C. indica, and compound (6) was found in abundance in A. bisporus. Correlations are suggested between the occurrence of these compounds in mushrooms and consumption as well as beneficial health effects of this food.     

Silicon nanoelectronics and beyond: An overview and recent developments

This year marks the 40th anniversary of the invention of the first beam-lead device by Lepselter et al. Lepselter and coworkers proposed a method of fabricating a new semiconductor device structure and its application to high-frequency silicon switching transistors and ultra-high-speed integrated circuits. Beam-lead technology, also known as air-bridge technology, has established itself for its unsurpassed reliability in high-frequency silicon switching transistors and ultra-high-speed integrated circuits for telecommunications and missile systems. The beam-lead device became the first example of a commercial microelectromechanical structure (MEMS). Since its inception, MEMS has taken advantage of the evolving silicon technology, resulting in today’s nano-electromechanical structure and nano-optomechanical structure. In this paper, an overview of recent developments of silicon nanoelectronics is presented. For more information, contact N.M. Ravindra, New Jersey Institute of Technology, Interdisciplinary Program in Materials Science and Engineering, Department of Physics, Newark, New Jersey 07102; (973) 596-3278; fax (973) 642-4978; e-mail nmravindra@comcast.net.     

Iterative weighted EM and iterative weighted EM′-index for scientific assessment of scholars

Scientometrics - In the field of scientific assessment of scholars, there were several metrics has been given by the scholars. From the list of indices, the h-index is widely accepted for the...     

Statistical-information-based performance criteria for Richardson-Lucy image deblurring

Iterative image deconvolution algorithms generally lack objective criteria for deciding when to terminate iterations, often relying on ad hoc metrics for determining optimal performance. A statistical-information-based analysis of the popular Richardson-Lucy iterative deblurring algorithm is presented after clarification of the detailed nature of noise amplification and resolution recovery as the algorithm iterates. Monitoring the information content of the reconstructed image furnishes an alternative criterion for assessing and stopping such an iterative algorithm. It is straightforward to implement prior knowledge and other conditioning tools in this statistical approach.     

Fabrication,characterization and comparison of DSSC using anatase TiO2 synthesized by various methods

In this study, anatase TiO₂ nanoparticles were synthesized by three techniques, namely, sol–gel, acid-base co-catalyst and room temperature colloidal methods. The synthesized materials were characterized by X-ray diffraction, scanning electron microscopy, pore diameter, pore volume and surface area. The dye-sensitized solar cells were fabricated using the synthesized materials and characterized for incident photon to current conversion efficiency, photocurrent density to photo voltage measurement and electrochemical impedance analysis. Among the studied materials, TiO₂ synthesized by sol–gel method displayed highest photon to current conversion of 76.8% and a maximum solar cell efficiency of 7.85% with J_sc of 14.75 mA/cm², V_oc of 0.76 V and FF of 0.7. This is the first study to report a high power conversion efficiency of DSSC using a sol–gel synthesized titania and its comparison with other two synthesized materials. The high power conversion efficiency of the solar cell using TiO₂ synthesized by sol–gel method is attributed to its characteristic properties such high surface area, larger pore diameter and larger pore volume and highest dye loading capacity.