Prediction of creep curve of HP40Nb steel using artificial neural network

Neural Computing and Applications - Simulation of creep curves using data obtained from a limited number of short-time creep tests is helpful for predicting the long-time creep life of materials by...     

Prevalence,characterization, and genetic diversity of Listeria monocytogenes isolated from foods of animal origin in North East India

Listeria monocytogenes is a pathogenic microorganism infects man mostly through food. A total of 1615 samples of foods of animal origin and water were collected from retail meat shops of North-Eastern India and processed. Sixty-three (3.9%) samples were positive for L. monocytogenes. Animal origin foods showing the highest prevalence was chevon (9.8%) followed by beef (8.9%), chicken (8.5%), pork (2.8%) and milk (1.8%). The prevalence rate in water from retail meat shops was 10%. Recovered L. monocytogenes were distributed into 3 serogroups, of which 74.6% fit in to 1/2a, 3a serogroup, 17.5% to 1/2b, 3b and 7.9 % to 4b, 4d, 4e serogroups. Thirty-five isolates out of 63 possessed all the tested four virulence genes. RAPD- and ERIC -PCR based analyses jointly revealed a discriminative genetic profile for the L. monocytogenes. On the whole, the occurrence of L. monocytogenes in foods of animal origin of North Eastern India displays public health hazard.     

Synthesis and characterization of polyaniline/carbon nanotube composites

The synthesis of polyaniline (PANI) containing different carbon nanotubes (CNTs) by in situ polymerization is reported in this study. The samples were characterized by X‐ray diffraction and scanning electron microscopy. Fourier transform infrared and ultraviolet–visible spectroscopy were used to determine the change in structure of the polymer/CNT composites. Thermogravimetric analysis showed that the composites had better thermal stability than the pure PANI. Photoluminescence spectra showed a blueshift in the PANI–single‐walled nanotube (SWNT) composite. Low‐temperature (77–300 K) electrical transport properties were measured in the absence and presence of a magnetic field up to 1 T. Direct‐current conductivity exhibited a nonohmic, three‐dimensional variable range hopping mechanism. The room‐temperature magnetoconductivity of all of the investigated samples except the PANI–SWNT composite were negative; however, it was positive for the PANI–SWNT composite, and its magnitude decreased with increasing temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of satellite footprint patterns from rectangular planar array antenna by using swarm‐based optimization algorithms

A pattern synthesis method based on Firefly Algorithm (FA) and Artificial Bee Colony (ABC) optimization has been presented to generate satellite footprint patterns from a rectangular planar array of isotropic antennas by modifying the amplitude, phase, and the state of the array elements. Three cases comprising three different footprints of rectangular, square, and circular boundary are generated from the same array by using two different swarm‐based optimization algorithms FA and ABC. Both the algorithms, following the proposed procedures are able to generate the three different footprint patterns while maintaining a satisfactory lower peak side lobe level and ripple. A comparative analysis has been carried out between FA, ABC, and Genetic Algorithm (GA) for the presented problem in terms of fitness value for the three different cases. The superiority of FA and ABC over GA has been established in terms of finding better solutions for all the three cases of the proposed problem. Copyright © 2013 John Wiley & Sons, Ltd.     

A moment-method characterization of V-Koch fractal dipole antennas

This article compares input impedances and radiation characteristics of half wavelength Koch fractal V–electric dipoles having included angles 60°, 90° and 120°. The study considers three structures. In the 1st structure the Koch arms open into the V-region, in 2nd structure they open away from the V-region and in the third structure, one arm opens into and the other away from the V-region. A first iteration, structure 1 of V-Koch electric dipole antenna with included angle of 120° was fabricated and the experimental return loss was in good agreement with simulation. At their first resonances the antennas’ gain and input resistance decrease with decrease in included angles, an observation synonymous to Euclidian electric dipoles. In terms of gain, the first structure is found to give better performance than the other two. For this structure, the pattern distortion at the second resonance was also less compared to the other structures.     

Studies on the dehydration kinetics and rehydration of YAG precursor powder in the hydroxyhydrogel form

YAG precursor powder was prepared in the hydroxyhydrogel form. Dehydration kinetic study and rehydration experiment was carried out to know the behavior of water molecules and hydroxide bonds present in the hydroxyhydrogel network structure with temperature. Rate constants and activation energies for dehydration and dehydroxylation were evaluated by static thermogravimetry. Percent rehydration was determined at different heat treatment temperatures. The results obtained were explained, correlated to establish the thermal stability of hydroxyhydrogel network structure and finally supported by the FTIR analysis.     

Electrothermal Response and Functional Characteristics of Barium Ferrocyanide–Based Squibs

In an attempt to replace toxic ingredients like lead ferrocyanide (LFCN) in electrical squibs, experiments were conducted by using barium ferrocyanide (BFCN) as an ingredient of squib composition. Electrothermal response (ETR), functional characteristics such as no-fire current (NFC) and all-fire current (AFC), were studied and compared with lead ferrocyanide-based squibs. Threshold firing currents were determined using the Bruceton staircase method. The squibs were also subjected to accelerated ageing and performance was evaluated. The results indicate better performance of barium ferrocyanide squibs to electrothermal response and a higher threshold no fire current, making it comparatively safe to handle as compared to lead ferrocyanide–based squibs. The results of accelerated ageing indicate a reasonable shelf life. ETR technique is found to be a good diagnostic tool for quality control.     

Satellite image segmentation with Shadowed C-Means

Satellite images often require segmentation in the presence of uncertainty, caused due to factors like environmental conditions, poor resolution and poor illumination. Since any subsequent image analysis depends on the quality of such segmentation, one has to obtain an efficient algorithm for the purpose. Pixel clustering is a popular way of determining the homogeneous image regions, corresponding to the different land cover types, based on their spectral properties. In this paper we map the newly developed shadowed clustering algorithm to the problem of segmenting remotely sensed images.It is observed that shadowed clustering can efficiently handle overlapping among segments while modeling uncertainty among the boundaries. Unlike rough clustering, here the choice of user-defined parameters is fully eliminated. The number of segments is automatically optimized in terms of validity indices. The algorithm is robust in the presence of outliers. The superiority of the system is demonstrated in segmenting a synthetic image, along with land cover types from the Indian Remote Sensing (IRS) images of the cities of Mumbai and Kolkata and the SPOT image around Kolkata. The algorithm is found to efficiently and accurately extract the different homogeneous regions in the presence of uncertainty. The results are analyzed both qualitatively and quantitatively.     

LIBS based spectroscopic analysis and antidiabetic evaluation of a polyherbal formulation

Although plants have long been a major source of medicine, there is renewed interest in studying the phytochemistry and use of herbal formulations. This paper reports spectroscopic analysis using Laser Induced Breakdown Spectroscopy (LIBS) of a polyherbal formulation, whose antidiabetic activity has also been demonstrated on rat models. LIBS analysis revealed the presence of elements such as Na, K, Mg, Ca, H, O and N. The antidiabetic study showed that amongst the four doses studied (50, 100, 150 and 200 mg/kg bw), the dose of 150 mg/kg bw registered the maximum fall in Blood Glucose Level (BGL) in both normal and diabetic (sub and mild) rats in the Glucose Tolerance Test (GTT) study—normal rats (22 %), sub-diabetic (36.6 %) and mild-diabetic (39 %). The dose of 150 mg/kg also showed the maximum fall of 23.7 % and 22 % in BGL during fasting BGL and GTT studies of normal rats, respectively. The formulation also showed significant antioxidant activity assessed using in vitro assays. The study validates for the first time the therapeutic use of an antidiabetic polyherbal formulation.