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: Renewable energy & Dielectric. 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.

First-principles study of SnO under high pressure

Abstract: This paper reports the first-principles study of SnO under high pressure within the generalized gradient approximation (GGA). We have calculated the structural, elastic, electronic and optical properties of SnO. The elastic properties such as the elastic constants Cij, bulk modulus, shear modulus, Young’s modulus, anisotropic factor, Pugh’s ratio and Poisson’s ratio are calculated and analyzed. Mechanical stability of SnO at all pressures is confirmed using the Born’s stability conditions in terms of Cij. It is also found that SnO exhibits very high anisotropy. The energy band structure and density of states are also calculated and analyzed. The results show the semiconducting and metallic properties at zero and high pressures, respectively. Furthermore, the optical properties are also calculated. All the results are compared with those of SnO where available but most of the results at high pressure are not compared due to the unavailability of results.

Workability, strength and microstructural properties of ground ferronickel slag blended fly ash geopolymer mortar

Abstract: This study evaluated the effect of using ground ferronickel slag (GFNS) with fly ash (FA) to produce geopolymer mortar. Workability of mortar was found to decrease with the increase of GFNS content...

Heat transfer performance evaluation and prediction of correlation for turbulent flow through a tube with helical tape inserts at higher Reynolds number

Abstract: An experimental investigation was accomplished to evaluate the performance of heat transfer for turbulent flow through a tube with helical tape inserts. The mild steel helical tape inserts with different twist ratios of 1.88, 3.13, 4.69, 6.41 and 7.81 were used in the flow field. Heat transfer and pressure drop data were prompted for a wide range of Reynolds number from 7200 to 50,000. The experimental results indicated that the Nusselt number, friction factor and thermal performance factor were increased with decreasing twist ratio. The results also showed that helical tape inserts of different geometries in a circular tube enhanced the heat transfer rate significantly with corresponding increase in friction factor. Nusselt number and friction factor for the tube with inserts were found to be increased up to 260 and 285 %, respectively, than those over the plain tube values at the comparable Reynolds number. The heat transfer performance was evaluated and found to be 44 % higher compared to the plain tube based on the constant blower power. Finally, new correlations were proposed for the twist ratios ranging from 1.88 to 7.81 for predicting the heat transfer, friction factor and thermal performance factor for turbulent flow through a circular tube fitted with helical tape inserts.

Improved Sampling and Feature Selection to Support Extreme Gradient Boosting For PCOS Diagnosis

Abstract: PolyCystic Ovary Syndrome (PCOS) is one of the most common causes of female infertility, affecting a large number of women of reproductive age, even continuing far beyond the childbearing years. This hormonal disorder may further lead to the risk of other long-term complications. Considering the powerful recognition abilities of the probabilistic nature of ensemble-based gradient boosting algorithms, particularly in the field of the medical domain, we propose the use of Extreme Gradient Boosting, XGBoost, for early detection of PCOS. To strongly support an effective classification performance, we have resampled our data using a combination of SMOTE(Synthetic Minority Oversampling Techniques) & ENN (Edited Nearest Neighbour), to solve class imbalance and data outliers issues. Also, by exploiting popular statistical correlation methods, ANOVA Test Chi-Square Test, we have identified 23 most significant metabolic and clinical parameters that best classify PCOS conditions. Finally, we experimented with our model on a benchmark dataset collected from Kaggle to justify the effectiveness of our proposed findings where the Extreme Gradient Boosting classifier outperformed all other classifiers with a 10 Fold Cross-validation score of 96.03 % all over, along with a 98% Recall in the detection of patients not having PCOS, which outperforms all the existing recent methods where the numerical data-driven diagnosis of PCOS have been studied on this particular dataset.

Slow arsenic poisoning of the contaminated groundwater users

Abstract: This paper gives impact of Arsenic contaminated water on human health as well as overview of the extent and severity of groundwater arsenic contamination in Bangladesh. Scalp hair is the most important part of the human body to monitor the accumulation of this type of poison. Therefore, an experiment has been carried out by Neutron Activation Analysis (NAA) at Atomic Energy Research Establishment (AERE), Savar, Dhaka, Bangladesh on human hair of corresponding tube well water users of these areas to determine the total accumulation of arsenic to their body. Hair samples collected from the region where the groundwater was found highly contaminated with arsenic. The obtained results of arsenic concentration in the lower age (Hb) categories of users (below 12 years of age users) is in the range of 0.33 to 3.29 /gmg/g (ppm) and that in the Hu categories (upper 12 years of age users) is 0.47 to 6.64 μg/g (ppm). Where as maximum permissible range is 1 ppm certified from WHO. Results show that the peoples are highly affected where the groundwater is highly contaminated with arsenic and acts as the primary source of arsenic poisoning among the peoples of those areas. The results indicate that human population is affected with arsenic locally using the contaminated water for a long time.