Mohammad Zoynal Abedin

Dhaka University of Engineering & Technology | DUET · Mechanical Engineering

Transient thermosolutal convection of Boussinesq fluid with moving heating and cooling blocks placed at the bottom wall in a square cavity was numerically investigated subject to vertical gradient of thermosolutal conditions at the top or bottom walls. With the progress in time, due to the interactions among thermal and solutal buoyancy and stratif...

Direct numerical simulations were performed for the transitional and turbulent natural-convection boundary layer for air and water along a hot vertical flat plate. The numerical results for water well reproduce the vortex-like structures as observed experimentally in the thermal field for a high Prandtl-number fluid. When the calculated values are...

Time-developing combined-convection boundary layers induced by imposing aiding and opposing flows to the natural-convection boundary layer in air along a hot vertical flat plate have been examined with a direct numerical simulation. As the freestream velocity increases, the transition from laminar to turbulence delays for aiding flow and quickens f...

Time-developing direct numerical simulations are performed for the combined-convection boundary layers created by imposing aiding and opposing freestreams to the pure natural-convection boundary layer in air along a heated vertical flat plate to clarify their structural characteristics. The numerical results reveal that with a slight increase in fr...

Time-developing combined-convection boundary layers with aiding and opposing freestreams in water along a heated vertical flat plate have been examined with a direct numerical simulation (DNS) to clarify their transition and turbulence behaviors. The numerical results for aiding flow reveal that the transition begins at a thick laminar boundary lay...

Biomass power plants play a crucial role in the sustainable energy sector by converting organic materials such as agricultural residues, forest biomass, and dedicated energy crops into electricity and heat. Biomass power plants represent a viable and renewable energy solution that can contribute to transitioning to a low-carbon economy. Their abili...

This paper aims to analyze the process of tungsten inert gas and metal inert gas welding and the defects of welding. Metal inert gas and Tungsten inert gas welding are the most popular gas-shielded arc welding processes used in many industrial fields. MIG welding is more highly efficient than TIG welding. This research has focused on welding defect...

The automobile industry is one of the growing industries in Bangladesh. Compared to the last decennary, the growth of the automobile industry has gradually increased due to the economic development and purchasing capacity of the middle and upper-middle classes people of the country. As reported by the Bangladesh Road Transport Authority, the unit o...

Plastic is a major hazardous problem for any biosphere. Presently, the use of plastic has been remarkably increased and hence, the necessity arises to reduce the usage of these materials. Properties of plastic materials make its disposal process difficult and complex though it is one of the widely used man-made materials due to its few specific cha...

Bangladesh's automotive industry is the third biggest in South Asia. Bangladesh has several famous automobile factories which assemble Mitsubishi and Proton vehicles, Hino and Tata commercial vehicles. Motorcycles, auto rickshaws and the locally built Mishuk tricycle are fabricated in Bangladesh. The gross domestic product growth of Bangladesh has...

The present study was undertaken to evaluate the performance efficiency of an Effluent Treatment Plant (ETP) of a Textile industry located at Tongi, Bangladesh with biological treatment (BT) and Membrane Bio-Reactor (MBR) with an average inflow of 300 m3/hr. The effluent samples were collected from the inlet and outlet of the ETP on a weekly basis...

The readymade garment industry in Bangladesh is one of the foremost significant export-oriented industries, but it faces issues in ensuring worker safety. Industrial accidents threaten workplace safety, which is additionally amongst the foremost critical challenges in the world's industries. The objectives of this paper are to explore the numerous...

Boiling heat transfer can play a vital role in the two-phase flow applications. The analysis of the boiling hat transfer enhancement is of importance in such applications and the enhancement can be mostly conducted by using various active and passive techniques. One type of passive techniques is the enhancement of heat transfer by nanofluids. This...

Solid waste is an inevitable by-product of human beings, animals and also of industrial-commercial activities. Obviously solid waste creates a greater problem to the environment, if it is not properly managed. Bangladesh being a heavily populated country needs to pay adequate attention to waste management. Waste generation in Bangladesh is increasi...

Heat generation of engineering appliances has bad effect in handling the system can cause the trouble, short life cycle of machines, frequent maintenance requirements and low reliability of systems. The passive cooling technique has been widely used to solve such problems. This review work summarizes the heat transfer enhancement technique in a rec...

Due to increase in temperature at the cutting zone, the tool wear and surface roughness along with the non-uniform chip formation and the dimensional deviation of the job by using the conventional cutting fluid, the machining operation experts have directed their concentrations in order to achieve a smooth machining operation by using minimum quant...

The heat transfer enhancement is recycled in many engineering uses such as heat exchangers, refrigeration and air conditioning structures, chemical apparatuses, and automobile radiators. Hence many enhancing extended fin patterns are developed and used. In multi louvered fin, in this segment for multi-row fin and tube heat exchanger, an increase in...

The heat transfer enhancement is recycled in many engineering uses such as heat exchangers, refrigeration and air conditioning structures, chemical apparatuses, and automobile radiators. Hence many enhancing extended fin patterns are developed and used. In multi-louvered fin, in this segment for multi-row fin and tube heat exchanger, an increase in...

The scientists revise the heat transfer enhancement techniques time to time to achieve better performance and to obtain optimized designs of heat exchangers. The present study reviews the performance and techniques of heat transfer enhancement using various insert devices such as twisted tape and wire coil insert as well as completely different for...

The application of natural fibers could be enhanced manifold by using them together with synthetic fibers, which can potentially reduce the cost of the hybrid composites. In this study, vacuum assisted resin infusion process has been used to fabricate composites using woven jute fibers (six layers) and carbon fibers (four layers) with four differen...

The consequence of placing a different layer of jute and carbon fiber in different position inside the composite has been experimentally investigated. Six layers of woven unidirectional jute fiber and four-layer of carbon fiber has been used with five different stacking sequences in this study. Vacuum Assisted Resin Infusion (VARI) technology has b...

Due to higher price, limited supply and negative impacts on environment by fossil fuel, automobile industries have directed their concentrations in reducing the fuel consumption of vehicles in order to achieve the lower aerodynamic drag. As a consequence, numerous researches have been carried out throughout the world for not only getting the optimu...

This paper reports an experimental analysis to investigate the enhancement of turbulent heat transfer flow of air through one smooth tube and four different tubes with wire-coil inserts (Pitches, Pc = 12, 24, 40, and 50 mm with corresponding helix angles, a =100, 200, 350, and 450, respectively) at low Reynolds numbers ranging from 6000 to 22000. T...

Time-developing direct numerical simulation (DNS) was performed to clarify the higher-order turbulent behaviors in the thermally-driven boundary layers both in air and water along a heated vertical flat plate. The predicted statistics of the heat transfer rates and the higher-order turbulent behaviors such as skewness factors, flatness factors and...

This paper describes the results of accelerated particulate fouling tests performed on three enhanced tubes and a plain tube. The tests were performed using ferric oxide and aluminum oxide as foulant materials. Three enhanced tubes included 25 start, 10 start helically ribbed tubes and a ripple tube. Effects of the water velocity (0.9 to 1.8 m/s) a...

An experimental investigation has been carried out for the first law analysis of a DI (direct-ignition) diesel engine running on straight soybean oil (SVO) preheated at 50, 75, 100 o C with different loads at varying speeds of 1750, 2000, 2250 rpm. The results show that preheated straight soybean oil may be a practical replacement of the convention...

This paper introduces the basics of contracts related to engineering works and services. It also describes the process of contracting works to give an idea how the contract issues are framed out in the process. In addition, it describes the relationship and interfaces of engineering and law, definition and meaning of contract, types of contracts, a...

Time-developing thermally-driven boundary layers created by imposing aiding and opposing freestreams on the natural-convection boundary layer in water along a heated vertical flat plate have been examined with a direct numerical simulation. The numerical results reveal that, with a slight increase in freestream velocity, the transition to turbulenc...

Periodic maintenance refers to the regular, routine maintenance services that should be completed on vehicle to prevent untimely breakdowns and avoid the potentially gargantuan repair bills. It is simple an ounce of Periodic maintenance is worth several pounds of cure. Periodic maintenance services include testing, inspections, lubrication, adjustm...

A Direct Current motor is commonly employed for many industrial applications due to its high torque and efficiency. This article expresses an optimally designed controller of Direct Current motor speed control depending on the genetic algorithm (GA). The optimization method is used for searching for the ideal Proportional Integral Derivative (PID)...

To increase the uniformity of axial temperature profile for air flow in a tube with wire-coil-inserts and consequently to enhance the heat transfer at low turbulent Reynolds number, the use of wire-coil-inserts is developed and investigated experimentally. The wire-coil of pitch 12mm with helix angle  =45 0 was fabricated and inserted into the smo...