Polyphenylene sulphide/carbon fiber composites: study on their thermal,mechanical and microscopic properties

The present study investigates the thermal, mechanical and microscopic properties of polyphenylene sulphide/carbon fiber (PPS/CF) composites by incremental number of fiber layers. The composites were prepared by hand lay-up technique followed by compression molding. A superior matrix-reinforcement adhesion was attained without the use of coupling agent and mechanical stability of the composites improved with increasing fiber layers. Transverse rupture strength and bending modulus were improved by 59.84 and 125.21 %, respectively, without loss in toughness. Impact strength and hardness values were enhanced while storage modulus, loss modulus and damping factor were dropped by increases in fiber layers. Thermogravimetric analysis (TGA) indicated a gradual rise in thermal stability (16.84 %) of the composite as compared to pure matrix. Surface morphology and crack propagation were studied by optical microscopy. It was found that crack was propagated in a linear plane by applying load. In addition, scanning electron microscopy (SEM) illustrated steady alignment of fibers and uniform distribution of the matrix around reinforcement. Based on the obtained results, fiber layers showed great potential for enhancement of thermal and mechanical properties of the composites.     

The effect of polystyrene as a porogen on the fluoride ion adsorption of Zr(IV) surface-immobilized resin

A novel adsorbent, Zr(IV)-immobilized resin, was prepared by surface template polymerization. This adsorbent, prepared by adding polystyrene (PS) to resin, has a high adsorption capacity for the removal of fluoride ion from aqueous solutions. The adsorption capacity increased with rising PS concentration, since the specific surface area can be effectively increased by adding polystyrene as a porogen. The adsorption isotherm has been modeled by the Langmuir and Freundlich equations. The adsorption isotherms were well described by the Langmuir equation. The removal of fluoride was also carried out using a column method. The presence of PS in the resin exerted a remarkable influence on the uptake of fluoride ion. The fluoride adsorbed on the resin was quantitatively eluted with 0.1 M NaOH.     

Inward vapor diffusion due to high temperature gradients in experimentally tested large-scale wall assemblies

Inward vapor flow due to high temperature gradients as a moisture source in building envelope has been documented, specifically when the exterior cladding is wetted by rain and then exposed to solar radiation. This phenomenon can bring large amount of undue moisture across the envelope assembly with a risk of damage of the wall elements. In this paper, inward vapor flow is applied to five large-scale monitored wall assemblies using a large-scale experimental facility consisting of a spraying array, a radiation array, and a test hut to provide controlled interior conditions. The variables studied include type of cladding (brick and cement stucco), presence and ventilation of air space, type of exterior sheathing (oriented strand board and extruded polystyrene) and type of interior finish (vinyl wall covering and paint). The results show that the presence of vapor tight interior finishes leads to the accumulation of moisture in the interior gypsum board, even in the presence of a vapor tight exterior sheathing. The presence of an air space reduces, but does not prevent moisture accumulation, while connecting the air space to the outdoor seems sufficient to short-circuit the inward vapor flow and prevent moisture accumulation.     

The effects of high school career education on social–cognitive variables.

The authors investigated the influence of a 9-week career education class on career decision-making self-efficacy, vocational skills self-efficacy, perceived educational barriers, outcome expectations, educational plans, and career expectations among a sample of 166 high school sophomores. Using a nonrandomized, within-subjects crossover design, the authors collected pretest, posttest, and follow-up data with a health education class as the control condition. Post- and follow-up testing suggest that the class resulted in increased career decision-making self-efficacy, vocational skills self-efficacy, and short-term gains in outcome expectations but did not influence perceived educational barriers. Participants enrolled in the career education class in the first quarter were more likely to change career plans than were those in the control condition. Implications for practice and future research are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microscopic brain tumor detection and classification using 3D CNN and feature selection architecture

Brain tumor is one of the most dreadful natures of cancer and caused a huge number of deaths among kids and adults from the past few years. According to WHO standard, the 700,000 humans are being with a brain tumor and around 86,000 are diagnosed since 2019. While the total number of deaths due to brain tumors is 16,830 since 2019 and the average survival rate is 35%. Therefore, automated techniques are needed to grade brain tumors precisely from MRI scans. In this work, a new deep learning‐based method is proposed for microscopic brain tumor detection and tumor type classification. A 3D convolutional neural network (CNN) architecture is designed at the first step to extract brain tumor and extracted tumors are passed to a pretrained CNN model for feature extraction. The extracted features are transferred to the correlation‐based selection method and as the output, the best features are selected. These selected features are validated through feed‐forward neural network for final classification. Three BraTS datasets 2015, 2017, and 2018 are utilized for experiments, validation, and accomplished an accuracy of 98.32, 96.97, and 92.67%, respectively. A comparison with existing techniques shows the proposed design yields comparable accuracy.     

Security & Privacy in Software Defined Networks,Issues, Challenges and Cost of Developed Solutions: A Systematic Literature Review

International Journal of Wireless Information Networks - Due to fast development in digital systems, the traditional network architecture is becoming inadequate for the requirements of new...     

Autolanding a Power-off UAV Using On-line Optimization and Slip Maneuvers

This paper tackles the final stages of autolanding a fixed-wing Unmanned Air Vehicle (UAV) in a power-fail emergency scenario. We applied the principle of Nonlinear Model Predictive Control (NMPC) to plan trajectories that respect the aircraft’s limits, and react on disturbances and environmental changes in real-time. However, thanks to judicious problem formulations, our algorithm optimizes—in each time step—the whole horizon of the landing trajectory, and settles a dynamic compromise between the different touchdown requirements. Furthermore, the algorithm is powered by a novel method that utilizes slip maneuvers to achieve adequate energy control notwithstanding the absence of specialized drag control devices. Thus, precise touchdown point is attained even in the presence of strong wind shear and large initial errors. All design parameters are optimized off-line over a wide spectrum of conditions using Genetic Algorithm (GA). Monte-Carlo simulation of the optimized design shows excellent landing performance and high success rate on both flat and sloping terrains.     

Modification of cotton fabric for textile dyeing: industrial mercerization versus gamma irradiation

The current research is intended to investigate the effect of gamma radiation on the cotton fabric and compare the dyeability of gamma irradiated fabric with that of chemically mercerized fabric using reactive dye, Reactive Violet H3R. The gray cotton fabric samples were desized and bleached, before being mercerized or irradiated, followed by dyeing with reactive dye. The cotton fabric was exposed to variable absorbed doses of 2–10 kGy. The color strength values at various levels of temperature, pH, dyeing time, and salt concentration were evaluated using optimal conditions of mercerization and gamma-ray treatment. The comparison of color strength values for the mercerized and the gamma irradiated cotton fabric showed that the irradiated fabric had high color strength at 60 °C using dye bath of pH10 in the presence of 6 g/L of exhausting agent while dyeing for 40 min. Both mercerization and irradiation increased the surface area of fibers that substantially elevated the dyeing performance and fastness properties.