Mechanical Engineering

Piston which is used in internal combustion engine does some important jobs, it is a load bearing component, which take load from combustion chamber and transfer them straight and true through the connecting rod to the crankshaft. Materials for the piston are cast aluminium, forged aluminium and forged steel etc. The alloy from which a piston is made not only determines its strength and wears characteristics, but also its thermal expansion characteristics. Hotter engines require more stable alloys to maintain close tolerances without scuffing. Aluminium alloys are the ideal materials due to their very high thermal conductivity. At first materials of the casting is chosen, then the design of the piston is accomplished and finally the piston is constructed by die casting. This thesis paper, covering over effective references, aims to shed new light on the issues related to the piston.

With the increasing demand of high performance electronic devices, computer systems, integrated circuits (IC) and microchips, the power densities in the electronic systems are increasing rapidly. It is very important to facilitate optimum cooling of electronic components in an electronic device because integrated circuit lifetime depends on it. This experimental study has been performed to investigate the thermal performance of looped parallel micro heat pipe (LPMHP). LPMHP consists of two single tube micro heat pipes of circular geometry. The experimental parameters are condenser inclination angle, heat input and properties of the working fluid. Taking acetone and ethanol as working fluids, thermal performances are determined experimentally for different condenser inclination angles at different heat inputs. From the analysis it is observed that for the same heat input and condenser inclination angle LPMHP with acetone as working fluid performs better.

Usage of wind energy has been increased in recent times especially because of its availability and lost cost rate. In Bangladesh wind energy is a very recent concept and yet several place research is going on to measure the wind speed. Both private and government organizations are working but without coordination. This paper presents the problems during the time of implementing wind energy and the strategy for promotion and development of wind energy in Bangladesh to solve that problem. With improved design for wind turbines, financial package, political will to support large-scale wind projects through public sector undertakings, and a remunerative price for wind generated electricity, it is hoped that wind energy will play a supplementary role to meet the growing power demands in the country.

In the last decade, the importance of environment conservation has assumed great
significance. Even in Bangladesh the last couple of years have witnessed a greater devotion and awakening towards the protection of the environment. Pollution due to petroleum products used in transportation is an ever-increasing problem for Bangladesh like other country. So alternative solution of energy source is trying to use, thus pressure on Compressed Natural Gas (CNG) has been increased. Though, the environmental problem is solved but the stock of gas is simultaneously decreasing. The use of CNG as an alternative vehicular fuel in Bangladesh is increasing day by day because the country has a significant natural gas resources and the gas transmission and distribution network is also well developed. The government of Bangladesh is taking few steps for coordination between the environmental awareness concept and the use of the CNG in sectors. The purpose of the study is to find out present scenario of Bangladesh of using CNG as vehicular fuel and find out some proper ways for the environmental and economic benefits of the country. And the commercialization of CNG as well as the growth pattern of CNG conversion workshops in Bangladesh.

The use of CNG in Bangladesh is increasing day by day due to the environmental benefits as well as economic benefits. In the last decade, the importance of environment conservation has assumed great significance. Even in Bangladesh the last couple of years have witnessed a greater devotion and awakening towards the protection of the environment. Pollution due to petroleum products used in transportation is an ever-increasing problem for Bangladesh like other country. So alternative solution of energy source is trying to use, thus pressure on Compressed Natural Gas (CNG) has been increased. Though, the environmental problem is solved but the stock of gas is simultaneously decreasing. The purpose of the study is to make coordination between the environmental awareness concept and the use of the natural gas should be connected in such a manner to achieve the success of Bangladesh.

This research focused on the experimental analysis of the thermal response of a solid base plate (mimic to skin) and also the performance of fire protective fabric under hot air jet impingement situation. This investigation utilized a fabricated attachment with an axial flow wind tunnel for horizontal hot air jet of different velocities and temperatures that impinged on vertical base plate. The experiments were conducted without fabric, cotton fabric and fire protective fabric to understand the unprotected situation as well as protective condition. The air jet temperatures were 115o C and 125o C. The hot air jet velocities were 12, 15, and 19 m/s at the exit point of the nozzle. The variations of the nozzle-to-plate separation were 2, 4 and 6 with respect to nozzle diameter. The fabrics were placed in contact and 6 mm away from the base plate during the experiments. Seven thermocouples were employed at different radial locations of the base plate to measure the surface temperatures of the solid base plate by using data acquisition system. The surface temperatures were used to calculate the surface heat flux, local heat transfer coefficient, and Nusselt numbers at different nozzle-to-plate separations. The experimental results show the maximum decrease of heat flux by using the protective fabric. The significant heat transfer was also occurred for cotton fabric. In addition, the heat transfer through the fabric was also observed, which varied on nozzle-to-plate separation and Nusselt number.

Now-a-days Energy crisis is intensifying in Bangladesh. For this reason experts are emphasizing on the sources of sustainable energy and its aspects. Researchers are enduring many experiments and collecting eminent data on Wind Energy as the future of this sector is very prosperous and highly potential. The main achievement of this sector lies in the improvement of aerodynamic efficiency and reliability, leading to lower cost per kWh generated. But the main problem is that there is no proper wind energy management system was developed. A model of the wind energy management system is developed and its outcomes have been given in this paper.  It also shows the correlation among educational, industrial and government workforces. Wind energy sector will be revolutionary changed with the implementation of wind energy workforce development.

This paper represents an experimental investigation of the transient heat transfer on a solid base plate (mimic to skin) covered by fire retardant fabric (Kevlar® 49), under hot air jet impingement. The study was carried out by a fabricated attachment with an axial flow wind tunnel for horizontal hot air jet impingement. The hot air jet was impinged on a vertical base plate at different velocities and temperatures. A set of experimental conditions was considered to understand the various heat transfer phenomenon. The hot air jet temperatures were 115 and 125 °C respectively and jet velocities were 12, 15, and 19 ms−1 respectively at the exit point of the nozzle. The surface temperatures of the solid base plate are used to calculate the heat flux, local heat transfer coefficient, and Nusselt numbers. The maximum heat transfer is found on base plate, whilst the maximum decrease of heat flux is observed on fire retardant fabric. This experimental model can enhance the understanding and insights of the heat transfer process through permeable fabric.

This article aims to identify the energetic and exergetic efficiencies and the losses in different components of a 250 MW coal based thermal power plant. The analysis has been carried out by considering the design data as well as the operational data at varying load conditions. The distribution of the exergy losses in power plant components has been assessed to locate the process irreversibility. Basically, the power plants are designed based on first law of thermodynamics that does not afford to calculate useful energy losses of the system due to the quality and quantity of energy difference. This study deals with the comparison of energy and exergy analyses of the Barapukuria coal fired thermal power plant of Bangladesh, which deals with both first and second law of thermodynamics. Operation and maintenance decisions based on exergy analysis (second law analysis) would be more effective for operation of the thermal power plant.

Bangladesh transport sector is still heavily dependent on imported oil in an effort to support its growing economy. The volatile oil prices and the unstable political situation of the Middle East, put the government of Bangladesh in a politically compromising position and force the country to a big amount of financial loss every year in the fuel and energy sector. Becoming energy independent has been a long-term goal for Bangladesh, a logical governmental goal is to decrease use of fossil fuel and increase use of domestically produced alternative energy sources. Adopting compressed natural gas (CNG) and Liquefied Petroleum Gas (LPG) in old vehicles and encouraging alternative fuel driven vehicles and electric vehicles in Bangladesh would improve national, political and environmental standing. Imposing new rules and VAT and Taxes on both CNG conversion product and recondition car, CNG and LNG sectors are going towards downstream. The government of Bangladesh should take necessary steps in well advance to make clean and environment friendly transportation systems and to become energy independent country. Thus, the market of alternative fuel driven vehicle has got a chance to explore to meet the future challenge. This paper shows how to meet the future challenge of the vehicular fuels in Bangladesh.

Sophisticated cooling technologies are essential to cool gas turbine airfoils, as the hot gas temperature in gas turbines is far above the permissible metal temperatures to maximize the thermal efficiency. Internal cooling is widely used in modern gas turbine airfoils for the high cooling performance. Among different internal cooling techniques, teardrop-shaped dimple surface is a prominent method for high heat transfer performance and low pressure drop. In the present study, in order to investigate the effects of rotation-angle of teardrop-shaped dimples on heat transfer enhancement, experiments were performed by transient technique with compensation of three-dimensional heat conduction analysis. Three-dimensional thermal conductivity analysis was performed by finite volume method in OpenFOAM. The vertical direction temperature gradient on the dimpled surface was calculated for the Reynolds number in a range of 16,000 to 36,000. Five different rotation angles were examined in the present study, where whole 0 deg dimpled surface was rotated by 15, 30, 45, and 60 deg. The experimental results revealed that the highest heat transfer occurred at 30 deg rotated dimpled surface at the Reynolds number of 16,000 to 36,000. The highest friction factor was found at 30 deg dimpled surface and lowest friction factor found for 0 deg dimpled surface. The overall heat transfer performance of the airfoil internal cooling was evaluated in terms of heat transfer efficiency index and the maximum value was found for 30 deg rotated dimpled surface.

Background: Alopecia induced by standard chemotherapy gives deep grief to breast cancer patients. Even if the hair will grow again after chemotherapy, it needs more than one year to recover the natural hair status without using wig. We applied the scalp cooling system of Cool Cap for breast cancer patients during chemotherapy. It can avoid alopecia perfectly or decrease hair loss in our patients. One patient's hair is growing during chemotheraphy after chemotherapy-induced alopecia (CIA) by the first regimen of weekly paclitaxel without Cool Cap. Methods: Since December 2017, we have applied the scalp cooling system, PAXMAN Cool Cap, on ten breast cancer patients. The cooling cap is choiced its size and farmly compressed to the whole patient scalp. The whole scalp is evenly cooled to 20 centigrade. Pre-cooling time is 30 minutes. Scalp cooling is continued during the chemotherapy. And post-cooling time is 90 minutes. The chemotherapy regimens are standard as docetaxel, nab-paclitaxel, TC, and EC. All these regimens are supposed to give alopecia to almost all patients, without Cool Cap. Its effect is evaluated by the toxicity scale of WHO and the original scale of hair volume and patchy loss area. Results: The regimens are applied docetaxel to ten patients, nab-paclitaxel to one patient, TC to two patient, and EC to 7 patients for early and metastatic breast cancer patients. The evaluation of alopecia was grade 0 on fourteen patients, grade 1 on four patients, and grade 2 on two patient. Two patients needed hair wig for hair loss. One patient with CIA has her hair growing during the second part of chemotherapy with Cool Cap. Headache was prevented by NSAID. All patients were satisfied with this application of Cool Cap. Conclusions: The Cool Cap system is suprisingly effective to prevent CIA. It should be standard therapy for all breast cancer patients on chemotherapy. MO2 À 3 À 3 Analysis of epidemiological characteristics and treatment for male breast cancer patients in Japan

Background: Globally, cervical cancer is one of the leading causes of morbidity and mortality amongst the gynecological cancers, especially in developing countries like Bangladesh. This present study was carried out to assess the knowledge and awareness about cervical cancer and its prevention among the female respondents of General Hospital of Tangail District in Bangladesh.

Methods: A cross-sectional, face to face interview-based survey was conducted in September to January (2018-2019) using self-administered questionnaire to elicit information on demographic characteristics, knowledge, screening behaviors and determinants of cervical cancer.
Results: A total of 478 patients participated in the screening process, out of which 71.4% (342) were illiterate whereas only 8.8% (42) were graduate. Of all the interviews conducted, 51.5% did not know cervical cancer risk factors as a disease. Only 48.5% of the respondents were aware concern cervical cancer risk factors. On the other hand, only 14% respondents were aware that infection is the most common cause of cervical cancer and the cervical cancer causing virus is Human Papilloma Virus (HPV). Only
19.9% of the study population was aware of HIV as a risk factor for cervical cancer. Our study shows that 7.1% recognized Pap smear as a screening test of cervical cancer. In total, only 251(52.5%) out of 478 respondents were aware of the treatment of cervical cancer.

Conclusion: The present study revealed very low cervical cancer knowledge and poor understanding about the risk factors, diagnosis and the treatments among the women. Broad range epidemiology based study is strongly recommended in every general hospitals in Bangladesh for the proper awareness and concern about the cervical cancer risk factors and its early diagnosis.

Introduction The aim of this research is to develop a robot-assistive training approach for the disabled individuals with impaired upper limb functions. People with impaired upper limb function can regain their motor functionality undergoing intense rehabilitation exercises. With increasing number of disabled individuals, we face deficiency in the number of expert therapists. One promising remedy could be the use of robotic assistive devices. Method To instruct and demonstrate rehabilitation exercise, this research used NAO robot. A library of recommended rehabilitation exercises involving shoulder (i.e., abduction/adduction, vertical flexion/extension, and internal/external rotation), and elbow (i.e., flexion/extension) joint movements was formed in Choregraphe (graphical programming interface). For this purpose, a kinematic model of human upper-extremity was developed based on modified Denavit-Hartenberg notations. Result In experiments, NAO robot gave voice instruction and was ma...

In this paper, we focus on the human upper limb rehabilitation scheme that utilizes the concept ofteleoperation. Teleoperation can help the therapist demonstrate different rehab exercises to a different group of people at the same time remotely. Different groups of people from a different place connected to the same network can get therapy from the same therapist at the same time using the telerehabilitation scheme. Here, we presented a humanoid robot NAO that can be operated remotely by a therapist to demonstrate the exercise to a patient. To mimic the movement demonstrated by the therapist, Kinect V2 sensor which is a markerless vision-based motion-tracking device, was used. Modified Denavit-Hartenberg (DH) convention was used for the kinematic modeling of the human upper arm. From the Kinect data, a geometric solution was developed to find a unique inverse kinematic solution of human upper-extremity. Experimental results revealed that NAO could be teleoperated successfully to ins...

Proper functioning of human upper limb is substantially important when it comes to activity of daily livings (ADL). Loss of full or partial mobility in upper limb following stroke would make it difficult to perform ADL. Rehabilitating those who lost motor function is one of the way to get their upper limb in use preforming ADL as it was before. We, therefore, have developed an extensive rehabilitation library using NAO robot in which NAO could demonstrate the exercise therapist wants patient to perform. To demonstrate rehabilitation exercises with NAO, a library of recommended rehabilitation exercises involving shoulder (i.e., abduction/adduction, vertical flexion/extension, and internal/external rotation), and elbow (i.e., flexion/extension) joint movements was formed in Choregraphe (graphical programming interface). In experiments, NAO was maneuvered to instruct and demonstrate the exercises from the library. A complex ‘touch and play’ game was also developed where NAO plays with ...