Jessore University of Science & Technology

About: Jessore University of Science & Technology is a based out in . It is known for research contribution in the topics: Adsorption & Population. The organization has 811 authors who have published 974 publications receiving 10471 citations.

Synthetic approach of ternary magnesium niobate (Mg-Nb-O) compounds.

Abstract: Magnesium based niobium oxides (Mg-Nb-O) were prepared by solid-state reactions owing to understand the function of transition metal oxides as promoters/catalysts for practical application. Magnesium niobate (Mg3Nb6O11) was synthesized for the first time in nearly pure form reported in this context. MgNb2O6 and Mg4Nb2O9 were prepared in oxidizing conditions; on the contrary, Mg3Nb6O11 preferred reducing environment. Stoichiometric mixtures of the precursor materials MgO, Nb2O5 and/or metallic Nb were annealed for the syntheses which revealed the effect of temperature on phase formation, reaction kinetics and heat of reaction. The products were examined by ex-situ, in-situ X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Crystallographic parameters of various binary and ternary compounds (Mg/Nb/O) formed in different calcination conditions, were extracted by Rietveld method. In-situ experiment results in single step reaction for the MgNb2O6 synthesis and the heat of formation of the solid-state reaction obtained to be minimum (93 kJ/mol). In contrast, the formation of Mg4Nb2O9 and Mg3Nb6O11 compounds towards pure phases rather complicated due to multistep reactions and corresponding heat of formation were estimated to be 140 and 190 kJ/mol. Experimental results have been discussed based on kinetic and thermodynamic constrains.

A Nonlinear Model For The Optimal Capacity Placement In Self-Healing ATM Networks Based On Link Restoration Strategy

Abstract: Network Survivability is a critical issue in telecommunications network due to increasing dependence of the society on communication systems. Fast restoration from a network failure is an important challenge that deserves attention. This thesis addresses an optimal link capacity design problem for survivable asynchronous transfer mode (ATM) network based on the link restoration strategy. Given a projected traffic demands and the network topology, capacity and flow assignment are jointly optimized to yield the optimal capacity placement. The problem is formulated as large-scale nonlinear programming and is solved using a specific type of Lagrange method (so called Separable Augmented Lagrangian Algorithm or SALA for short). Several networks with diverse topological characteristics are used in the experiments to validate our proposed novel model, using capacity installation cost, routing cost, total network cost, used capacity and required CPU time, as performance metrics. Link restoration strategy is compared against global reconfiguration strategy using these performance metrics.

Health-related quality of life and coping strategies adopted by COVID-19 survivors: A nationwide cross-sectional study in Bangladesh

Abstract: This study aims to investigate the health-related quality of life and coping strategies among COVID-19 survivors in Bangladesh.This is a cross-sectional study of 2198 adult, COVID-19 survivors living in Bangladesh. Data were collected from previously diagnosed COVID-19 participants (confirmed by an RT-PCR test) via door-to-door interviews in the eight different divisions in Bangladesh. For data collection, Bengali-translated Brief COPE inventory and WHO Brief Quality of Life (WHO-QoLBREF) questionnaires were used. The data collection period was from October 2020 to March 2021.Males 72.38% (1591) were more affected by COVID-19 than females 27.62% (607). Age showed significant correlations (p<0.005) with physical, psychological and social relationships, whereas gender showed only a significant correlation with physical health (p<0.001). Marital status, occupation, living area, and co-morbidities showed significant co-relation with all four domains of QoL (p<0.001). Education and affected family members showed significant correlation with physical and social relationship (p<0.001). However, smoking habit showed a significant correlation with both social relationship and environment (p<0.001). Age and marital status showed a significant correlation with avoidant coping strategies (p<0.001); whereas gender and co-morbidities showed a significant correlation with problem-focused coping strategies (p<0.001). Educational qualification, occupation and living area showed significant correlation with all three coping strategies(p<0.001).Survivors of COVID-19 showed mixed types of coping strategies; however, the predominant coping strategy was avoidant coping, followed by problem-focused coping, with emotion-focused coping reported as the least prevalent. Marital status, occupation, living area and co-morbidities showed a greater effect on QoL in all participants. This study represents the real scenario of nationwide health-associated quality of life and coping strategies during and beyond the Delta pandemic.

Fiber Bragg Grating Sensors for the Detection of Metal Crack Initiation by Low Cycle Fatigue Test

Abstract: Structural integrity is always an important issue for the service life time of any structure. Therefore, joint of the metal is also a vital point to consider. This thesis describes a new method that uses the Fiber Bragg Grating (FBG) sensor to detect the crack initiation of friction stir welded aluminum (AL) alloy by low cycle fatigue test. Experimental setups and procedures are studied, a proper test configuration is determined and a series of testing performed. The applicability of this new method of stress control fatigue test in monitoring the metal crack initiation is demonstrated through the test results, which shows that FBG sensors are sensitive to capture the onset of the crack. Stress controlled fatigue tests especially at high strain amplitude for Friction Stir Welded (FSW) joints demand the sensors to withstand strain level above ±8000 με [40] and with the size of few mm, and these sensors are not available in the market. In this work, the new sensors arrays are used in the characterization of cyclic deformation behavior of FSW aluminum alloy, which, in some cases, could sustain up to ±11000με. During the experiment significant difference in plastic strain amplitude (PSA) was observed using these optical fiber sensors mounted in nugget zone (NZ) and across the boundary area between thermo mechanical affected zone (TMZ) and heat affected zone (HZ). For all the samples of Al alloy, with the progress of cyclic deformation the cyclic hardening characteristics of the metal were observed.