Crack interaction study in piezoelectric materials under thermo-electro-mechanical loading environment

Multiple voids and cracks were generated during material processing techniques, which interact with each other and affects the service performance of piezoelectric components. This work aims to study the behavior of piezoelectric components in presence of multiple cracks under thermo-electro-mechanical loading environment. Extended finite element method has been implemented to model geometrical discontinuities with crack interaction phenomenon. In this work, thermo-electro- mechanical problem has been decoupled into thermal and electro-elastic problems. Temperature distribution has been obtained by solving heat conduction equation and then used as an input to the electro-elastic problem. In post processing phase, interaction integral method and generalized Stroh formalism were used to predict the stress intensity factors. The methodology has been implemented with in-house developed MATLAB code. Set of cases for crack interaction studies were presented using the proposed approach.

     

A sustainable multi-parametric sensors network topology for river water quality monitoring

Wireless Networks - The deterioration of water quality due to natural and man-made hazards has affected the life on the Earth. Hence, water quality needs to be monitored regularly. The traditional...     

A new hybrid teaching–learning particle swarm optimization algorithm for synthesis of linkages to generate path

This paper proposes a novel hybrid teaching–learning particle swarm optimization (HTLPSO) algorithm, which merges two established nature-inspired algorithms, namely, optimization based on teaching–learning (TLBO) and particle swarm optimization (PSO). The HTLPSO merges the best half of population obtained after the teacher phase in TLBO with the best half of the population obtained after PSO. The population so obtained is used subsequently in learner phase of TLBO. To validate the proposed algorithm, five constrained benchmark functions are considered to prove its robustness and efficiency. The proposed algorithm is applied to synthesize four-bar linkage for prescribed path. It is found that the HTLPSO performs better than other single nature-inspired algorithms for path synthesis problem in mechanism theory. Hence, HTLPSO may prove to be an important tool for mechanism design to follow the prescribed path.     

Tiled ChrI RHS collection: a pilot high‐throughput screening tool for identification of allelic variants

Reciprocal hemizygosity analysis is a genetic technique that allows phenotypic determination of the allelic effects of a gene in a genetically uniform background. Expanding this single gene technique to generate a genome‐wide collection is termed as reciprocal hemizygosity scanning (RHS). The RHS collection should circumvent the need for linkage mapping and provide the power to identify all possible allelic variants for a given phenotype. However, the published RHS collections based on the existing genome‐wide haploid deletion library reported a high rate of false positives. In this study, we report de novo construction of a RHS collection that is not based on the yeast deletion library. This collection has been constructed for the shortest yeast chromosome, ChrI. Using this ChrI RHS collection, we identified 13 allelic variants for the previously mapped loci and novel allelic variants for the growth differences in different environments. A few of these novel variants, which were fine mapped to a gene level, identified novel genetic variation for the previously studied environmental conditions. The availability of a genome‐wide RHS collection would thus help us uncover a comprehensive list of allelic variants and better our understanding of the molecular pathways modulating a quantitative trait. Copyright © 2014 John Wiley & Sons, Ltd.     

Sintering of a Ceramic at Very Low Temperatures

Surface area, linear shrinkage, and compressive strength measurements show that, with the help of neutron irradiation, sintering of high-purity alumina can be initiated at temperatures lower than 150°C; such radiation sintering might be beneficial to many other ceramics.     

Menstrual cycle phase effects on nicotine withdrawal and cigarette craving: a review.

Evidence suggests that women are less likely to quit smoking than are men. This may reflect differences in nicotine dependence and, more specifically perhaps, nicotine withdrawal and craving. However, there is conflicting research on gender differences on the experience of withdrawal and craving. Menstrual cycle effects may moderate this relationship. Given hormonal changes during the menstrual cycle, abstinence-related symptoms such as withdrawal and craving may vary as a function of menstrual phase as well. This qualitative review summarizes the modest but expanding body of research in this area. One of the challenges inherent in interpreting this literature is the difficulty in distinguishing withdrawal symptomatology from premenstrual symptomatology. Methodological variation, including limited sample size and possible selection bias, in which several studies finding null effects excluded women with severe premenstrual dysphoric disorder, may explain some of the inconsistent findings across studies. Nonetheless, some of the 13 studies included in this review found heightened experiences of withdrawal or craving within the latter days of the menstrual cycle (i.e., the luteal phase). Further research is necessary to replicate these findings, but they may suggest the need for focused cessation treatment during the luteal phase or quit attempts that are well timed relative to specific menstrual phases.     

Anomalous high pressure behaviour in nanosized rare earth sesquioxides

We report Raman spectroscopic studies of the nanosized rare earth sesquioxides, namely yttrium sesquioxide (Y(2)O(3)), gadolinium sesquioxide (Gd(2)O(3)) and samarium sesquioxide (Sm(2)O(3)), under high pressure. The samples were characterized using x-ray diffraction, Raman spectroscopy and atomic force microscopy at atmospheric pressures. Y(2)O(3) and Gd(2)O(3) were found to be cubic at ambient, while Sm(2)O(3) was found to be predominantly cubic with a small fraction of monoclinic phase. The strongest Raman peaks are observed at 379, 344 and 363?cm(-1), respectively, for Y(2)O(3), Sm(2)O(3) and Gd(2)O(3). All the samples were found to be nanosized with 50-90?nm particle sizes. The high pressures were generated using a Mao-Bell type diamond anvil cell and a conventional laser Raman spectrometer is used to monitor the pressure-induced changes. Y(2)O(3) seems to undergo a crystalline to partial amorphous transition when pressurized up to about 19?GPa, with traces of hexagonal phase. However, on release of pressure, the hexagonal phase develops into the dominant phase. Gd(2)O(3) is also seen to develop into a mixture of amorphous and hexagonal phases on pressurizing. However, on release of pressure Gd(2)O(3) does not show any change and the transformation is found to be irreversible. On the other hand, Sm(2)O(3) shows a weakening of cubic phase peaks while monoclinic phase peaks gain intensity up to about a pressure of 6.79?GPa. However, thereafter the monoclinic phase peaks also reduce in intensity and mostly disordering sets in which does not show significant reversal as the pressure is released. The results obtained are discussed in detail.     

Screening and sequencing of glycated proteins by neutral loss scan LC/MS/MS method

Nonenzymatic protein glycation is caused by a Schiff's base reaction between the aldehyde groups of reducing sugars and the primary amines of proteins. A reversed-phase liquid chromatography method followed by a neutral loss scan mass spectrometric method was developed for the screening of glycation in proteins. The neutral loss scan was based on a unique sugar moiety neutral loss (-162 Da) that we observed in the fragmentation spectra of glycated peptides on Q-Tof type mass spectrometers. The collision energy was optimized for this neutral loss using a glycated synthetic peptide, and 20 eV was found to be the optimum collision energy. The neutral loss scan experiment was composed of two segments. In the first segment, the glycated peptides were identified based on the signature neutral loss of 162 Da when the collision energy was elevated to 20 eV. In the second segment, the glycated peptides were selected as the parent ions and fragmented at higher collision energy to break the peptide bonds. The fragmentation spectra of the selected glycated peptides revealed both the amino acid sequences and the sites of glycation. This neutral loss scan method was used to study the glycation in human serum albumin (HSA). The glycation sites in HSA were identified based on the retention time shift of glycated peptides, the mass accuracy from the MS scan, the signature neutral loss, and MS/MS information. Using this method, we were able to identify that 31 lysine residues were partially glycated from the glycated HSA sample, which has a total of 59 lysine residues.     

Controlled drug release characteristics and enhanced antibacterial effect of graphene nanosheets containing gentamicin sulfate

A novel methanol derived graphene (MDG) and gentamicin sulfate nanohybrid was prepared, and the loading and release behaviour of gentamicin on MDG is investigated. An efficient drug loading of 2.57 mg mg(-1) was obtained at pH 7. By applying release kinetic models, the mechanism of release of the drug from the MDG matrix was found to be following the Korsmeyer-Peppas model. However, the diffusional release exponent (n) value lies below 0.5 demonstrating that the mechanism controlling the drug release is the Fickian diffusion.