Zahid Hasan

The performance of household refrigerator compressor depends mainly on the mass flow rate through the reed valves. The suction and discharge valve leaves are designed to trap and deliver the refrigerant respectively during each piston movement cycle. Therefore, the edge radius of the valve leaves is a vital parameter that affects the mass flow rate, structural performance, and the fatigue life. In this research, the effects of different edge radii on the suction valve leaf for different materials have been determined with static structural analysis. Additionally, the natural frequency has been determined with modal analysis for the free and undamped cases to establish the relationship with different edge radii. The numerical simulation proved that the factor of safety increase with the increment of edge radius but there is no significant effect on vibration. Also, the fatigue life has been determined.

Success and business reputation depend upon the quality of products where product quality relies on the capability of a process, yield value, sigma score, etc. The poor quality of ceiling fans was determined from the Pareto analysis of the define, measure, analyze, improve and control (DMAIC) model, which was humming noise during running, and further actions were undertaken regarding the reduction of the humming noise. Noise data were collected from random samples to determine the current sigma score, which was 3.14. Also, the weak value (1.05) of the Process Potential Index implied that the process condition was below the standard (< 1.33) and needed to be improved badly. Then, root cause analysis and relationship diagram were used to identify the possible causes. With the design of experiments and correlation analysis, it was clear that the air gap between the stator and rotor was the main culprit behind the humming noise. The suitable range of air gap was determined from boxplot analysis, which was 0.2 mm–0.225 mm and the corresponding amount of sound level in dB (37.5–40.3 dB) for a 0.225-mm air gap with the watt consumption (83 w) from the hypothesis test for the corresponding air gap. Finally, the updated sigma score and process capability analysis were performed with control charts to show the comparison after applying the DMAIC-Six Sigma methodology. The final sigma score was 5.1, which indicates a significant improvement of the process with the capability of saving 23,438 USD/year caused by the poor quality of ceiling fans.

Purpose: Underdeveloped along with developing countries face enough crisis of human resources in high-tech industries. As a result, the amount of waste is higher along with less productivity. Highly qualified and smart employees are required as the term “Industry 4.0” introduces a lot of sophisticated and complex technologies that dominates productivity. But in those countries, to cope up with this terminology; neither the educational curriculum and method of teaching has been modified nor changed yet nor will be modified soon. So, the engineering students should be introduced with the aims and technologies of Industry 4.0 and its key technologies so that they can prepare themselves as highly skilled and qualified human resources besides academic courses.Design/methodology/approach: This article mainly depicts the causes of poor technical skills of the engineering students of Bangladesh and a new learning process has been proposed. The model proposed is basically inspired by Kaizen philosophy consisting of initiation, sharing and implementation cycles. The key aspects of human resource quality and the possibility of gaining innovative human resources for smart industries are given equal priority here. The prime factor to evaluate any learning outcome is quality and this research is a structured guideline to achieve sustainable quality education needed for “Industry 4.0” to engineering students.Findings: This paper provides statistical analysis on “Fitness of undergraduate engineering students for Industry 4.0”. After applying the proposed methodology on 130 students from different public engineering institutes of Bangladesh, the significant improvement of effectiveness in learning various topics of “Industry 4.0” besides academic studies has justified the method to be a successful one measuring by the criteria for fitness of human resource. This research aims to clarify the sustainable and work-based learning goals and methods for Science, Technology, Engineering and Management (STEM) students and professional courses.Research limitations/implications: This is a research where the proposed methodology was applied upon academically enrolled engineering students and the result was very satisfactory. A sustainable learning strategy for developing professional skills from academic life can result in better productivity at the beginning of a career. However, this methodology can be applied for job holders or professionals besides their office hours thus it is the future scope of this research methodology.Originality/value: This research represents the crucial factors related to technical education and skill development for the upcoming challenges and possible remedies needed for Industry 4.0. Therefore, students should become aware of their carrier challenges and the administration concerned for education to minimize the scarcity of skilled human resources needed for the Fourth Industrial revolution.

Most of the people living in developing or less developed countries have limited earning to provide somehow their basic needs & usual staff. Carrying goods is a regular task in life & several products have been invented to minimize efforts in this purpose. But the product’s price & features are not optimum for the people of fewer earnings. Stair climbing cart is very useful for those houses where a lift is not available and goods have to be carried frequently upstairs. In this research, the mechanical design has been modified so that the manufacturing cost can be minimized. Finite element analysis has been performed upon the design to find out how the manufacturing cost can be reduced by making the design optimal for manufacturing cost and process. The result shows that the structural members should not be processed further because any tooling operation will require an extra machine as well as an extra cost. Only the wheels are possible to subject under optimization by reducing material as well as weight. This article will be a valuable asset for the mass manufacturers of this type of product.

Most of the people living in developing or less developed countries have limited earning to provide somehow their basic needs and usual staff. Carrying goods is a regular task in life and several products have been invented to minimize efforts in this purpose. However, the price and features of most available products are out of the reach for the people of limited earnings. Stair climbing cart is very useful for those houses where a lift is not available. In this research, a modified mechanical design with eight wheels providing pause-rest feature has been represented with the equations of pulling force, constraints of stair dimensions and climbing mechanism. The ‘House of Quality Diagram ‘(QFD)’ has been added to accomplish the vision of further market research and customer satisfaction. The factor of safety and different types of stress have been determined for different types of loads and conditions. In addition, the details of the material with dimension, design and feasibility analysis have led this research to uniqueness.

Spur gears are the most well-known kind of gears used in hybrid vehicle’s power transmission. They have straight teeth, and are mounted on parallel shafts. In some cases, many spur gears are utilized without a moment's delay to make huge rigging decreases. In this paper how stress creates on a spur equip under various conditions and conditions and reenactments of a rigging system (two spur gears) is assessed by Ansys workbench. For this static structural and dynamic analysis modeling is utilized. A couple of spurs equip tooth in real life is by and large subjected to two sorts of cyclic stress: contact stress and twisting stress including bowing fatigue. The two stresses may not accomplish their greatest esteems at a similar purpose of contact fatigue. These sorts of failure can be limited by analysis of the issue amid the outline organize and making appropriate tooth surface profile with legitimate assembling strategies.

In the present world, nuclear energy is a must need for various purposes. The main cause of nuclear energy is because of the increasing energy demand, which is not possible to provide by using convenient energy generation. Bangladesh is a lower income country and the energy sector is not so developed here though there is a very high demand for energy. Rooppur Nuclear Power Plant is the only one nuclear generation plant which can provide this kind of huge energy within a very short time. This paper mainly depicts the ins and outs of this plant and discusses it’s feasibility in Bangladesh. It also focuses on the worlds various power generation methods and comprises it with nuclear energy generation. A detailed technical brief is presented in this paper along with advantages, location selection, financial and environmental impacts. This will help researchers to do further researches about nuclear energy in Bangladesh.

This research is directed to the hybridization of battery and ultra-capacitor for a better effectiveness. This portrays the benefits of introducing an ultra-capacitor into a battery pack of an urban electric vehicle drive train. Matlab Simulations are done taking two basic scenarios into consideration: fresh cells and half-used battery cells. The simulations show that the lower the temperature (25-28 OC) higher the hybrid system efficiency (25-30%). Data from real world and previous studies are considered to conduct this study. Previous studies showed efficiency raise upto 7%, whereas this system showed around 14% efficiency raise. Simulations are done considering modified Bangladeshi drive cycle for low weight vehicles. Several issues like volumetric, gravimetric and cost issues of hybridization are present in this paper. By this system the power loss of the system can be reduced by up to 5% to 10% regarding to conventional system. Finally hybridization not only increases the efficiency of the energy storage system also increases the power train efficiency and battery lifespan. This paper would help researchers for further development of this topic.