Teaching Performance of Primary School Teachers and its Impact on Students’ Academic Achievement in Bangladesh.

The study mainly dealt with the teaching performance of primary school teachers and its impact on students’ academic achievement in Bangladesh. It reveals the teaching performance of teachers considering five important indicators. The academic achievement was also looked into account examining the five important indicators. Social survey method was adopted and both primary and secondary data were used. Data were collected through questionnaire and interviews. Sample was taken randomly and the total number of sample was 120. 60 teachers of govt. and 60 teachers of non-govt. primary schools were taken to make a comparison. 15 Govt. and 15 non-govt. primary schools were taken to assess the policy implementation including other formal activates. The study has found that there are some lacks of teachers in performing their duties. For this reason, the academic achievement of the students’ is not satisfactory in both of the govt. and non-govt. primary schools. Comparatively the performance of govt. primary school teachers is more satisfactory than non-govt. primary school teachers in Bangladesh. So, the students’ academic achievement is low as to the expectation in both of the govt. and non-govt. primary schools. Keywords: Teaching Performance, Primary School, Academic Achievement, Bangladesh

Post-Operative Outcome of Desarda Repair of Inguinal Hernia in Emergency Case in Bangladesh

Background: Desarda hernia repair has emerged as a recognized operative method for inguinal hernia repair. Objective: The purpose of the present study was to see the outcome of emergency inguinal hernia repair by Desarda technique. Methodology: This was an observational study was carried out in the Department of Surgery at Sher-E-Bangla Medical College Hospital, Barisal, Bangladesh and Private Hospital, Narayanganj, Bangladesh from August 2015 to January 2017. Twenty patient was operated by Desarda technique. Variables includes age, operating time, post-operative complications, post-operative hospital stay, cost of the procedure, chronic groin pain and any early recurrence. Result: Mean age of patient 50.25±18.9, Mean operating time was 78.4±9.64 mins. Majority 16 patient experienced mild post-operative pain measured in VAS score. Mean with SD of hospital stay was 5.05±2.16 days. Patient had developed different post-operative complications like wound infection in 2(10.0%) cases, scrotal edema in 5(25.0%) cases, seroma formation in 1(5.0%) case and no early recurrence and. Conclusion: In this study, it revealed that Desarda repair was associated with less post-operative complications, less post-operative pain, zero recurrence rate, no chronic groin pain and performed in emergency cases. So it is safe and most reliable technique for complicated (Incarcerated, Obstructed, Strangulated) inguinal hernia. Journal of Current and Advance Medical Research 2020;7(1): 44-4

Metal-Air Batteries—A Review

Metal–air batteries are a promising technology that could be used in several applications, from portable devices to large-scale energy storage applications. This work is a comprehensive review of the recent progress made in metal-air batteries MABs. It covers the theoretical considerations and mechanisms of MABs, electrochemical performance, and the progress made in the development of different structures of MABs. The operational concepts and recent developments in MABs are thoroughly discussed, with a particular focus on innovative materials design and cell structures. The classical research on traditional MABs was chosen and contrasted with metal–air flow systems, demonstrating the merits associated with the latter in terms of achieving higher energy density and efficiency, along with stability. Furthermore, the recent applications of MABs were discussed. Finally, a broad overview of challenges/opportunities and potential directions for commercializing this technology is carefully discussed. The primary focus of this investigation is to present a concise summary and to establish future directions in the development of MABs from traditional static to advanced flow technologies. A systematic analysis of this subject from a material and chemistry standpoint is presented as well

Optimisations of a seasonal solar thermal energy storage system for space heating in cold climate

© 2019 Sheikh Khaleduzzaman ShahA number of seasonal solar thermal energy storage (SSTES) systems have been investigated for heating in cold climate locations due to the utilisation of solar energy. The system overcomes the drawback on the intermittency of solar energy and contributes to storing heat from summer to be used in winter. Heat pump and solar collectors with lower temperature thermal storage are the influencing factors to improve the system performance. A double U-tube borehole thermal energy storage (BTES) system integrated with ground coupled heat pump (GCHP) and evacuated tube solar collectors (ETSCs) is proposed for residential space heating in selected cold climate locations. Experimental data were collected from a double U-tube borehole heat exchanger (BHE) test rig; the data were used to validate the TRNSYS Type 257, which models double U-tube BHE. The performance of the proposed double U-tube BTES-GCHP-ETSC system was evaluated by computer simulations. A cluster of 30 residential houses in six selected cold climate locations: Lukla (Nepal), Dras (India), Sivas (Turkey), Harbin (China), Ulaanbaatar (Mongolia) and Verkhoyansk (Russia) were investigated. The design variables of the proposed system were optimised to minimise total life cycle cost (TLCC) and total life cycle greenhouse gas emissions (TLCG). The initial investigation was to provide a detailed review of various parameters (options) of SSTES systems. The BTES system has better energy performance with relatively low cost compare with other thermal storage systems. The lower temperature SSTES system may be more suitable for the cold climate conditions. However, the lower temperature stored heat cannot be directly used for space heating, and a heat pump needs to be coupled to upgrade the temperature of the delivered heat. The SSTES system is a promising technique for cold climate locations with adequate solar radiations. It was found that the annual average heating coefficient of performance (COP) of the heat pump, COP of the system, and the ground temperature are increased by adding solar collectors to a conventional heat pump (HP) system. In contrast, the required borehole depth, heat pump energy consumption and extracted energy from the ground are decreased due to the inclusion of solar collectors in the system. The highest COP of a heat pump is found at a system with ETSC compared to other solar collectors. Furthermore, double U-tube BHE has lower LCC and higher heat transfer rate than single U-tube BHE configuration. An experimental study was conducted to validate the TRNSYS Type 257. All system components, pipe network, data acquisition systems, operation procedures and schedules, weather station and measuring instrument were described. The experiments were conducted for heat charging and space heating operations. The measured undisturbed ground temperature (UGT) at the experiment site was presented. The UGT were found to be 17.64 degree celsius and 17.68 degree celsius at 21 m and 40 m depth respectively. The validation of the double U-tube BHE model was presented. The simulated and measured temperatures were compared. Statistical parameters: mean bias error (MBE), root mean square error (RMSE) and correlation coefficient (CC) were used to quantify the agreements between the simulated and measured data. Both heat charging mode and space heating mode models were validated. The duration for the comparison was one-week for both operation modes. The CC of double U-tube BHE model was found to be 0.99 and 0.91 for heat charging mode and space heating mode respectively. The MBE were found to be 0.15 and -0.07 for heat charging mode and space heating mode respectively. The RMSE were 0.37 and 0.51 for heat charging mode and space heating mode respectively. A TRNSYS model was developed to simulate the proposed BTES-GCHP-ETSC system for a cluster of residential houses in selected six cold climate locations. The residential house model for each location was developed based on the typical local dwelling. It was found that the annual heating loads per unit floor area (in GJ m-2) are: 1.71, 1.79, 0.71, 1.19, 1.45 and 2.59 for, Lukla, Sivas, Dras, Harbin, Ulaanbaatar and Verkhoyansk respectively. The system was investigated for heat charging and space heating (heat discharging) modes where the ground temperature and heat losses were analysed. The results of the simulation over 20 years period showed that the average ground temperatures were stable in each location with solar charging option. The energy balance of the system at the 20th year was analysed. The highest seasonal compressor heating coefficient of performance (SHCOP) was found to be 6.65 at Lukla and lowest was 6.03 at Sivas. On the other hand, the highest COPsys (4.39) was found at Verkhoyansk and lowest (2.68) at the Sivas. It was found that the proposed system fulfils the 95%, 92%, 93%, 93%, 96% and 100% of space heating demand for Lukla, Sivas, Dras, Harbin, Ulaanbaatar and Verkhoyansk respectively. The TRNSYS simulation model coupled with multi-objective building optimisation (MOBO) software was used to optimise system variables. There are three separate optimisation investigations: two single objective and one multi objectives for the system. The first investigation is to minimise total life cycle greenhouse gas emissions (TLCG, t), and the second investigation is to minimise total life cycle cost (TLCC, $) included cost of GHGE. The third investigation is to minimise both life cycle cost (LCCRsysR) of system and cost of greenhouse gas emissions (Cghge) (multi objectives). The optimum proposed system configuration (total solar collector area, number of boreholes and total borehole length were determined. The annual life cycle cost (ALCC), the unit heating cost (UHC), net energy ratio (NER), simple payback time (SPBT), carbon payback time (CPBT), and energy payback time (EPBT) were determined to analyse the proposed SSTES system. The proposed SSTES system was optimised for minimising TLCG, where total amount of embodied and operational GHGE were considered for 20 years project life. The maximum GHGE was found at Dras and the minimum at Lukla. The maximum ALCC was found at Verkhoyansk and the minimum at Sivas. The maximum UHC was found at Sivas and the minimum at Verkhoyansk because the size of the heating system is larger at Verkhoyansk than other location. The maximum CPBT and SPBT were found at Sivas and the minimum at Lukla. The EPBT was found highest at Sivas where NER was found lowest. On the other hand, the EPBT was found lowest at Ulaanbaatar where NER was found highest. The maximum SHCOP and COPsys were found at Lukla and Dras respectively. In addition, the proposed BTES-GCHP-ETSC system was optimised for minimising TLCC for 20 years project life, where the system cost and cost of GHGE were considered. The maximum total life cycle cost (TLCC) (cost of system and GHGE) was found at Verkhoyansk and the minimum at Sivas. The operational cost was found highest at Verkhoyansk than other locations because the pumps operate longer to meet the heating demand. The cost of GHGE was the height at Dras and the lowest at Lukla. The ALCC was maximum at Verkhoyansk and minimum at Sivas. The maximum UHC was found at Sivas and the minimum at Verkhoyansk. The NER was found to be the height at Verkhoyansk and the lowest at Sivas. The maximum SPBT was found at Sivas and the minimum at Lukla. The minimum EPBT was found at Verkhoyansk and maximum at Sivas. The SHCOP were found to be 7.00, 6.03, 6.72, 6.22, 6.12 and 6.45 for Lukla, Sivas, Dras, Harbin, Ulaanbaatar and Verkhoyansk respectively. The COPsys were found to be 3.23 (Lukla), 3.57 (Dras), 2.68 (Sivas), 3.53 (Harbin), 3.52 (Ulaanbaatar) and 4.39 (Verkhoyansk). Further, multi-objectives optimisation of SSTES system for space heating in cold climate locations was investigated. Multi-objective functions were applied to determine the Pareto front of variables. The LCCsys and the Cghge were the two objective functions. The minimum LCCsys and the minimum Cghge points as the Pareto fronts were determined. However, minimum TLCC points have 53% (Lukla), 37% (Dras) and 42% (Ulaanbaatar) shorter borehole length than minimum TLCG points

A Systematic Review on Natural Language Processing and Machine Learning Approaches to Improve Requirements Specification in Software Requirements Engineering

This systematic literature review (SLR) examines the current practices, challenges, proposed solutions, and limitations of natural language processing (NLP) and machine learning (ML) approaches in improving requirements specification in software requirements engineering. The review focuses on research conducted in the last five years and includes a selection of papers that discuss the use of NLP and ML techniques for enhancing the accuracy and clarity of requirements, particularly in the context of functional and non-functional requirements. The findings highlight the benefits and challenges associated with the integration of NLP and ML approaches, such as improved classification and identification of requirements. However, it is observed that there is a greater emphasis on non-functional requirements, with a limited representation of research on functional requirements. Comparison of this review and the recent two reviews has been done to observe the differences and highlight the novelty and contribution. The review also identifies limitations, potential bias in assuming that problems related to requirements documentation or specification can be easily resolved through simple changes as well as the need to address the functional requirements. The insights from this SLR contribute to the understanding of the current state of research in this field and provide a foundation for future research directions and practical applications in leveraging NLP and ML approaches to enhance requirements specification in software requirements engineering. &nbsp

Rheological behavior of Al2O3/R141b nanorefrigerant

Nanorefrigerants are potential nanofluid that can improve the performance of refrigeration and air-conditioning system. Rheological properties of these fluids need to analyze before practical implementation as they influence the flow characteristics. In the present work, the rheological behavior (relation of shear stress and viscosity with shear rate) of Al2O 3/R141b nanorefrigerant for 0.05-0.15 volume concentrations with the temperature ranging from 4 to 16 C was studied. From this experiment, it is found that, the nanorefrigerant showed non-Newtonian and shear thickening behavior. However, at high shear rates, the trend was found to be quite close to Newtonian behavior. Moreover, viscosity increases with the increase of shear rates and volume concentrations, however, decreases with the increase of temperature. © 2014 Elsevier Ltd. All rights reserved