Physical Sciences and Engineering

A diffusion absorption refrigerator is a heat (sun heat) powered refrigeration system. It can be operated without any use of electrical or mechanical energy. It has no moving parts. The working fluid is a three component mixture: ammonia as refrigerant, water as absorbent and helium as inert gas used to equalize the total pressure in the evaporator-absorber compartment. In the present work a model of each element in this machine is developed. The considered machine is intended to be used for air conditioning applications.

The consideration of sustainable development and the governance reinvent a negotiation and consultation culture around the public stake concerns and fertilize the group animation practices. As regards development plan, policy and program evaluation, the strategic stakes negotiation process remains difficult and its success dubious.

The recent trend of research on joining of dissimilar alloys leads the interest towards the study and analysis of Friction Stir welding. Joining of different steel groups and Aluminium has been on the research interest on the previous decade. Recent innovative research and development area is on with Magnesium alloy groups. The Aluminium alloys and Magnesium alloys are investigated for the weld strength with respect to the change of welding parameters including tool geometry, the tool transverse speed, and the tool angular velocity.

In this thesis, the development of electrical porcelain insulators based on local clays has been investigated. The test samples were made by varying the quantities of silica and feldspar required to form a mouldable plastic body with each clay sample. The clay samples were bisque fired to 900°C and glazed before it was fired to 1250°C after air-drying. Electrical properties such as dielectric strength (breakdown voltage) were determined for each test sample that survived the high temperature.

The need Forecasting is an important part of planning and future growth. Many of an organization’s decisions are based on the prediction of future unknown events. This paper describes some statistical methods that can be used for time series forecasting.

The emerging applications of wireless networks enforce new challenges in design of algorithms and communication protocols. In such scenario of challenges, coding for error control has be- come extremely important to provide robust communication and maintain quality of service. One method to improve Bit Error Rate (BER) while maintaining high data reliability, is to use an error correction technique like the Viterbi algorithm. The Viterbi algorithm provides an efficient method for Forward Error Correction (FEC) that improves channel reliability.

Sign Language is the mode of communication among the deaf and dumb. However, integrating them into the main stream is very difficult as the majority of the society is unaware of their language. So, to bridge the communication gap between the hearing and speech impaired and the rest in Bangladesh, we conducted a research to recognize Bangla sign language using a computer-vision based approach. To achieve our goals we used Artificial Neural Networks to train individual signs.

Health is the essential part of human that individual has to feel, perceive and act effectively. And it is required to provide correspondent ways for proper health care delivery in real time manner. The arrival of new technologies especially the Internet of Things (IoT) Strengthen the health care system through Wireless Sensor Network (WSN). In the current health care environment the IoT enables to connect different stakeholders in the health care system like patients, physicians, hospital, emergency unit and patient well-wishers etc. regardless of their current location.

This study ‘Water Quality, quantity and accessibility Assessment: Volcanoes national park region experience in Rwanda’ established the ways in which water is used, the level of demand, the level of supply, water quality, water quantity and accessibility around Volcanoes nation park of Rwanda. It has been hypothesised that there is a very high demand for water, lower lever of access due to population pressure and limited water sources.

There are various starting methods to start induction motors among them variable frequency System has more advantages. For controlling the speed of the induction motor we are using pwm technique based on current signature techniques as a feedback of closed loop system. For a all control methods rely on the pwm voltage waveform to control the motor. The difference between control methods lies in how they calculate the motors voltage needs at any given moment. Among these methods we are doing v/f control because it has advantages over all other methods.