Detecting and Mitigating Selfish Primary Users in Cognitive Radio

Wireless Personal Communications - In today’s world, Cloud computing based health cloud is an effective platform for enhancing e-health productivity, i.e., healthcare professionals can...     

AWJM Performance of jute/polyester composite using MOORA and analytical models

This work addresses the machinability performance of jute/polyester composites with variable laminate thickness using Abrasive water jet machining (AWJM) process. A hybrid objective function was developed using surface roughness (R_a) and kerf taper angle (T_a) and studied using a cost-effective Multi Objective Optimization by Ratio Analysis named as MOORA. The influence of machining parameters such as hydraulic pressure (P), feed rate (V_f) and standoff distance (S_d) on quality characteristics were considered for this analysis. Among all, V_f was found to be a strong influencing factor on T_a and R_a. The deviation in the magnitude of T_a and R_a was observed in the case of varying laminate thicknesses without affecting the optimum condition. Besides, a mathematical regression model was developed for both T_a and R_a based on the correlation between the dependent variables. Furthermore, two other models of R_a available in the literature were considered for comparison with experimental results. The results revealed the suitability of these models for the polymer-based fiber-reinforced composite materials, but limited to the maximum thickness of 3?mm. The good agreement of the models with two different sets of experimental values was also found.     

Investigation on Different Crystal Grains from the Multi-crystalline Silicon (mc-Si) Wafer

Silicon - We have studied the mc-Si wafers with different (hkl) planes. Initially, the wafer was chemically etched by the KOH (20wt%) and IPA (2%) in the Millipore water at 60 °C for...     

Effect of succinonitrile and nano-hydroxyapatite on ionic conductivity and interfacial stability of polyether-based plasticized nanocomposite polymer electrolytes (PNCSPE)

A series of novel plasticized nanocomposite solid polymer electrolytes (PNCSPE) consisting of polyethylene oxide as polymer host, lithium bisoxalatoborate as salt with different weight ratios of succinonitrile and nano-hydroxyapatite was prepared by membrane hot-press technique. The electrical property of PNCSPE was investigated by AC impedance analysis. The migration of lithium ion in the polymer matrix was confirmed from cyclic voltammetry study. The incorporation of different compositions of filler and plasticizer in the polymer matrix significantly enhanced the amorphous nature resulted in increase in ionic conductivity of PNCSPE. The maximum ionic conductivity was found to be in the order of 10^?3.1 S/cm.     

Defocus estimation from stroboscopic cryo-electron microscopy data

Defocus estimation is an important step for improving the resolution of single particle reconstructions. It can be troublesome to estimate the defocus from low-dose cryo-electron microscopy (cryo-EM) data, particularly if there is not sufficient contrast present in the Fourier transform of the micrograph. Most existing approaches estimate the defocus from the presence of Thon rings within the power spectrum, employing image enhancement techniques to highlight these rings. In this paper, an approach to estimating the defocus from a stroboscopic image series is described. The image series is used to obtain two statistical metrics: figure of merit (FOM) and Q-factor. These metrics have been used to estimate the defoci from low-dose stroboscopic cryo-EM data consisting of a variable number of images.     

Recent progress on synthetic strategies and applications of transition metal phosphides in energy storage and conversion

Continuous advancements in the field of energy conversion and storage, including the development, evaluation of abundant and inexpensive materials with good electrochemical performance, aim to meet the future energy demands. Transition metal phosphides (TMPs) have recently emerged as excellent energy conversion and storage materials due to their highly active surface sites, electrical conductivity, thermal and structural stability. TMPs exhibit numerous other desirable properties, like hardness and chemical stability, which result from the presence of strong M ? P bonds in the molecules. In this work, comprehensive review of recent advancements in research concerning TMPs and their applications in the area of energy conversion and storage was conducted. Additionally, the frequently employed synthetic strategies for the production of TMPs were investigated. Particularly, hydrogen and oxygen evolution reactions (HER and OER), dye-sensitized solar cells for energy conversion and storage, lithium-ion batteries, and supercapacitors were examined. TMPs display remarkable electrochemical behavior due to the synergistic effects of various compositions and surface structures. Moreover, the M-centers and P-sites possess high electrocatalytic activity. The P-sites of phosphides are negatively charged; thus, they attract protons, enhancing the HER/OER activities. Eventhough platinum-based electrocatalysts perform best in HER, their bifunctional properties have not been extensively studied due to poor OER activities. In energy storage, TMPs used as efficient and stable electrodes owing to their low charge-discharge potentials, high theoretical specific capacities, and a decreased ion-diffusion pathway. Finally, the challenges, future perspectives in the area of energy are discussed and several approaches for the improvement of multifunctional TMPs are proposed.     

Enhancement of Drucker-Prager yield model by adding corner points for pressure-dependent materials

Journal of Mechanical Science and Technology - To flexibly describe the pressure-dependent behaviors of materials, Drucker-Prager yield model is enhanced by introducing corner points. We call it...     

Investigation of structural,optical, and thermal properties of 2-amino-4,6-dimethylpyrimidine benzoic acid (2APB) single crystal for non-linear optical (NLO) applications

The 2-amino-4,6-dimethylpyrimidine benzoic acid (2APB) single crystal has been successfully grown by the slow evaporation method by using water as a solvent. The single-crystal X-Ray diffraction (SXRD) analysis gives knowledge about the structure and morphology of the 2APB crystal. The Powder X-ray Diffraction (PXRD) pattern of grinded 2APB crystal was compared with standard CIF file and the peaks were indexed with their corresponding miller indices (hkl). The crystalline perfection of the grown 2APB single crystal was analysed using high-resolution X-ray diffraction (HR-XRD) measurement. The various functional groups and their vibrational assignments were studied using the Fourier-transform infrared (FTIR) spectrum analysis. The 2APB crystal has a lower cut-off wavelength of 325 nm, which is evident from the UV–visible–NIR analysis. The defects and etch pit density of 2APB crystal were examined using chemical etching studies. The 2APB crystal was thermally stable up to 140 °C, which was evident from the thermogravimetric (TG) and differential thermal analysis (DTA). The photoconductivity analysis was carried out to calculate the photo and dark current values. The laser damage threshold (LDT) value was determined using a 532 nm Nd:YAG laser in single shot mode. The third-order non-linear optical (NLO) susceptibility (χ⁽³⁾) value was calculated from Z-scan technique, which involves open and closed aperture measurements.

     

Formation of face-contact interaction in 2D/2D/2D heterostructure ternary nanocomposites of g-C3N4/MoS2/GO for effective photocatalytic activity against the organic pollutants under the visible light irradiation

Journal of Materials Science: Materials in Electronics - Face-contact heterojunctions in 2D materials effectively separate the charge carriers and enhance the degradation efficiency of the...     

Enhancement of the analytical solution for double torsion test using extended finite element techniques

The double torsion (DT) testing technique is not yet standardized for fracture mechanics characterization of brittle materials because previous analytical solutions are insufficient to represent accurate load-displacement (P-h) relationship and stress intensity factor (SIF) in experiments. Therefore, we attempt at enhancing the analytical solutions based on three-dimensional extended finite element (XFE) analysis to obtain reproducible results from DT tests. As a result, the P-h relationship in DT test can be efficiently described by combining the bending deformation of a DT specimen with torsional deformation. Weighting factors are proposed as functions of thickness, moment arm and crack length. DT experiments are conducted with sodalime glass specimens to further validate the proposed weighting factors. Finally, correction terms are provided for SIF and fracturs toughness evaluation in DT specimen with straight and curved crack fronts. Fracturs toughness values of sodalime glass specimens with various thickness are consistent, and in good agreement with literature values.