Chittagong University of Engineering & Technology

About: Chittagong University of Engineering & Technology is a education organization based out in Chittagong, Bangladesh. It is known for research contribution in the topics: Computer science & Renewable energy. The organization has 1200 authors who have published 1444 publications receiving 10418 citations. The organization is also known as: Engineering College, Chittagong & Bangladesh Institute of Technology, Chittagong.

Ionisation of metastable 3P-state hydrogen atom by electron with exchange effects

Abstract: In the present work, the triple-differential cross-sections (TDCSs) for the ionisation of metastable 3P-state hydrogen atoms at an incident electron energy of 250 eV with exchange effects are computed in the asymmetric coplanar geometry for various kinematic conditions. The final-state wave function of Das and Seal (Phys. Rev. A 47, 2978 (1993)) is used here. The results of the present calculation are compared with the available hydrogenic ground-state experimental data and other existing theoretical results. An analysis of the results reveals qualitative enhancement with other compared results. The implication of the present study offers an extensive scope for experimental verification in such a field of ionisation.

Spatiotemporal trends of selected air quality parameters during force lockdown and its relationship to COVID-19 positive cases in Bangladesh

Abstract: Worldwide improved air quality in different cities is reported influenced by lockdown came in force due to COVID-19 pandemic; however, as expected, such changes might have been different in different places. And what is still not very clear whether air quality pollutants have some link to account COVID-19 positive cases and death tolls. This study aims to evaluate the spatiotemporal variability of air pollutants and their relationship to COVID-19 positive cases in major cities in Bangladesh. The relevant data of air pollutants and COVID-19 positive cases are collected, analyzed, discussed for lockdown period of 26 March to 26 April 2020 in comparison to data for same period averaging over 2013 to 2019 for eight major cities in Bangladesh. To characterize air pollutants affected by lockdown, trend and rate of changes were carried out using Mann-Kandle and Sen's slope methods, while spatial variability across the cities was done using ArcGIS and statistics within ArcGIS. The substantial reduction of mean concentrations in the range of 30–65%, 20–80%, 30 - 80%, 65 - 90% and 75 - 90% across the cities is found during lockdown compared to typical mean in previous years for the PM2.5, PM10, SO2, CO, and NO2 concentrations in air. Among the cities studied, it is seen that relatively lesser reduction in Dhaka, Gazipur and Narayanganj and moderate reduction in Chittagong, Rajshahi, Khulna and Barisal, while significantly bigger reduction in Sylhet influenced by the city attributes and climatic variabilities. Among all the pollutants studied, the increasing trends of NO2 and CO in Dhaka, Gazipur and Narayanganj are unexpected even in lockdown pointing the effectiveness of lockdown management. Correlation among the air pollutants and confirmed COVID-19 cases across the cities depict foggy relationship, while PCA integrated over the cities revealed association with gaseous pollutants pointing stronger effects of NO2. This relationship illustrates air pollution health effects may increase vulnerability to COVID-19 cases.

Towards Lip Motion Based Speaking Mode Detection Using Residual Neural Networks

Abstract: Speaking mode (i.e., talking or non-talking) detection is a significant research problem in the area of HCI and computer vision. Detecting the speaking mode of a speaker is quite challenging owing to the coarse-resolution images, interaction styles, and various noises. This paper proposes a vision-based technique to identify a human’s speaking mode in terms of talking and non-talking state by using the residual neural networks. Visual lip motions is a prominent cue and play a pivotal role in detecting the speaking mode of the human. Thus, we consider the vision-based technique rather voice-based, which is noisy or interrupted. The evaluation result in two datasets shows better performance (of \(99.56\%\) accuracy) in mouth state detection than previous approaches. Moreover, analysis with 36 min long video data of 15 participants reveals that the proposed technique acquired an accuracy of \(98.88\%\) in detecting speaking mode.

MHD free convection heat and mass transfer flow through a porous medium in a rotating system with hall current and heat generation

Abstract: The present work is the focused on steady Magneto hydrodynamics (MHD) free convection boundary layer flow of an incompressible electrically conducting fluid through a porous medium over a semi-infinite vertical plate in a rotating system with heat generation and the effects of Hall current are taken into account. The governing boundary layer equations are transformed into a set of non-linear ordinary differential equations for primary velocity, secondary velocity, temperature and concentration equations which are then solved numerically by the shooting method along with Runge-Kutta fourth-fifth order integration scheme. The effect of entering parameters on the primary velocity, secondary velocity, the temperature and concentration profiles are presented graphically. Therefore, the results of primary velocity field and secondary velocity field increases for increasing values of Hall parameter and permeability parameter but other parameters decrease the velocities of the fluid flow. The temperature field decreases in the presence of magnetic parameter, heat generation parameter, Prandtl number, Soret & Dufour numbers and Grashof number and negligible decreasing effect for rotational parameter. Also, concentration profile decreases for increasing the values of heat generation parameter, magnetic parameter, Prandtl number and Schmidt number but concentration increases for the effect of Grashof number, Soret number & Hall parameter. The numerical results for the rate of heat transfer are compared with other authors when the magnetic field, Grashof number, rotational parameter, heat generation parameter and Dufour number are absent and found almost similar result.

Seismic slope failures: a numerical investigation by the smoothed particle hydrodynamics (SPH)

Abstract: Seismic slope failure is one of the most devastating geo-hazards, and development of rational mitigation strategy has the top priority accounting for both human and economic losses. The insight mechanics of slope failures under seismic triggering provides plausible information to seismic mitigation policy. Considering the inherent limitation of experimental analysis and traditional numerical methods, this research work aims to develop a fully three-dimensional particle method using smoothed particle hydrodynamics to capture the dynamics of slope failures subjected to different seismic actions. The sensitivity of two important seismic properties, frequency and peak ground acceleration, has been checked out and the significant effect observed from a set of scaled model analysis. Normalized run-out has been found to increase about 14% and 6% with an increase in frequency and acceleration, respectively. Unlike other methods, the displacement of scratched mass has been evaluated, and somewhat comprehensive slip surface with highly displaced particles has been seen. Later, the effect of soil properties and slope gradient has been checked out and effect of slope gradient considered to be one of the critical factors other than seismic parameters. A decrease of about 60% in run-out is seen with an increase in frictional angle values. Again, about 65% drop in run-out is observed with a decrease in the steepness of slopes. In a nutshell, the research works successfully develop a tool for seismic slope failure analysis and can be a prospective tool for further verification.