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.

Design and Optimization of an Efficient Molybdenum Disulfide (MoS 2 ) Solar cell with Tin Sulfide BSF

Abstract: Two-dimensional molybdenum disulfide (MOS 2 ) is a potential sunlight harvester due to low cost, layered type atomic structure, favorable electrical and optical properties. The performance of a molybdenum disulfide (MOS 2 ) photovoltaic cell is investigated by using the wxAMPS simulator. The hidden potentiality of Mos2is unfolded by using BSF strategy. The photoconversion efficiency is found 21.39% $(\pmb{J_{sc}}=\pmb{29.89}\ \mathbf{mA}/\mathbf{cm}^{\pmb{2}},\pmb{V_{oc}=0.841}\mathbf{V}$ and $\mathbf{FF}=\pmb{0.856}$ ) for $\mathbf{r}\ \ \pmb{1}\ \ \pmb{\mu} \mathbf{m\ MoS}_{\pmb{2}}$ absorber layer with 100 nm SnS BSF whereas in conventional structure, it is found 19.48% $(\pmb{V_{oc}=0.826}\mathbf{V}, \pmb{J_{sc}}=\pmb{27.848}\ \ \mathbf{mA}/\mathbf{cm}^{\pmb{2}}$ , and $\mathbf{FF}=\pmb{0.846)}$ without BSF for 1 $\pmb{\mu} \mathbf{m\ MoS}_{\pmb{2}}$ absorber layer. The measured temperature coefficient (TC) is $\pmb{-0.047\%/}^{\circ}\mathbf{C}$ for conventional photovoltaic cell structure and −0.046%/°C for a modified structure with SnS BSF. It indicates the better thermal stability of the modified structure compared to the conventional structure.

Comparative study of predicted MAX phase Hf 2 AlN with recently synthesized Hf 2 AlC: a first principle calculations

Abstract: The physical properties including thermodynamic and optical properties, electronic charge density, Fermi surface, Mulliken bond overlap population and Vickers hardness of newly synthesized MAX phase Hf2AlC and predicted Hf2AlN phase have been explored using density functional theory for the first time. We revisit lattice and elastic constants, band structure and density of states to weigh the reliability of our calculations. The mechanical and dynamical stabilities of these compounds have been ensured. The brittle nature of Hf2AlX (X = C and N) compounds is also confirmed by the Pugh (G/B > 0.57) and Poisson ratio (< 0.26). The electronic band structure and density of states show the metallic conductivity with foremost contribution of Hf-5d states at the Fermi level. The mixture of covalent, metallic and ionic bonding is ensured by Mulliken population and charge density mapping. Low Vicker hardness value indicates soft material and easily mechinable nature of the phases. The reflectivity curves show the maximum values of 93% at 10.3 eV and 99% at 13.7 eV for the compounds Hf2AlC and Hf2AlN, respectively, that endorse the capability of reducing solar heating of these compounds. Excellent correlations are also found in all physical properties of these compounds.

Different aspects of slope failures considering large deformation: application of smoothed particle hydrodynamics (SPH)

Abstract: Understanding the insight of slope collapse is necessary for effective hazard mitigation policy. The conventional method may not be able to capture the actual failure mechanics as these methods are based on simplified assumptions of the predetermined slip surface. Highlighting this real engineering problem, an attempt is made in this research to simulate different aspects of slope collapse numerically. Lagrangian particle-based continuum model, namely, smoothed particle hydrodynamics (SPH) has been used to develop a three-dimensional numerical slope model to understand the failure mechanics of unstable slopes. Both homogeneous and non-homogeneous slope models have been simulated, and the time history of naturally occurring failure planes has been tracked. A distinct slip surface has been seen from displacement contour of particles, which portray the innate response of a collapsed slope. The effect of soil properties on the response of slope surface has also been evaluated quantitatively by the different combination of non-homogeneous slope models. Afterwards, two conventional remedial measures have been simulated, and significant reduction of run-out length is seen, which can put a spotlight on future mitigation strategy in geotechnical hazard.

Copper telluride as a nobel BSF material for high performance ultra thin CdTe PV cell

Abstract: Thin-film CdTe is one of the leading materials for high efficiency, low-cost and stable PV cells. The formation of a stable, low resistance, non-rectifying back contact to p-CdTe thin-film is the most critical challenge associated with this technology, another main constraint of PV technology is its high cost. To reduce the cost, less material consumption is desirable. Thus research is leading toward ultra-thin CdTe PV cell. However, the use of back surface field (BSF) material is found to be better, effective and easier one among several methods still used to overcome the problem with the back contact. This paper numerically explores the possibility of high efficiency, ultra-thin and stable CdTe cells with Cu2Te BSF. The cell performances (Voc, Jsc, FF, efficiency, temperature stability) are investigated by recognized simulator `Analysis of Micro-electronics and Photonic Structures' (AMPS-1D). A modified structure of CdTe based PV cell SnO2/Zn2SnO4/CdS/CdTe/Cu2Te/Ni has been proposed over reference structure SnO2/ Zn2SnO4/CdS/CdTe/Cu. The simulated results have shown that the use of Cu2Te as BSF layer enhances the cell performances and has no adverse effect on cell stability. In this analysis the highest conversion efficiency of CdTe based PV cell without BSF has been found around 17% using CdTe absorber thickness of 5μm, on the other hand with the BSF the conversion efficiency has been found to be as high as 19.5% using only 0.6 μm thick CdTe absorber, which opens a new window for ultra-thin CdTe PV cells. Furthermore it was also found that the cell normalized efficiency linearly decreased with the increasing operating temperature at the gradient of -0.35%/C, which indicates better stability of the proposed CdTe PV cell.

Analytic wave solutions of beta space fractional Burgers equation to study the interactions of multi-shocks in thin viscoelastic tube filled

Abstract: The present work investigates the single and overtaking collision of multi-shock wave excitations having space fractional evolution in a thin viscoelastic tube filled with incompressible inviscid fluid. The previously proposed model equations are considered to study such physical scenarios. The spatial fractional Burgers equation is formulated by implementing the reductive perturbation method form the considered model equations. The new analytical solutions for single and overtaking collision of multi-shocks are constructed by implementing the rational exponential functions directly. With the changes of physical parameters, the behaviors of single and overtaking collision of multi-shocks are displayed graphically and described physically. It is found that the overtaking collisions of multi–shocks are produced with the presence of beta nonlocal operator. The single and interactions of multi-shocks are also significantly changed with the change of physical parameters. The obtained results are very useful in describing the nature of overtaking collision of multi-shocks in various environments, particularly in large blood vessels and further laboratory studies.