[en] Photosensitive gaseous detectors provide an attractive solution for photon localization over very large areas and under high illumination flux. They offer single photon sensitivity and possibility of operation under very intense magnetic fields normally encountered in high energy physics experiments. A large variety of photosensitive gaseous detectors has been developed over the last two decades and is successfully employed in numerous experiments in high energy and nuclear physics, plasma diagnostics and medical imaging. Here we discuss the recent progress made in UV-photo cathodes capable of operation under gas multiplication and visible photo cathodes providing, for the first time, the possibility of operating gaseous detectors in the visible range. (author)

[en] Determination of net recharge to the groundwater is of prime importance while managing irrigation and drainage system of the area. Without knowing the groundwater and recharge both systems irrigation and drainage, are two sides of one coin may mislead. In order to determine net recharge to the groundwater, the data of important parameters such as irrigation delivery at head of the channel, total losses, crop water requirement, water table fluctuation, operation hours of tube wells and surface drain discharge and shallow as well as deep ground water quality were measured for Rabi season (November, 1999 to March, 2000). Using different approaches such as actual observation of inflow and outflow components, change of water table and SURFER (Software), the net recharge was determined. Results have shown that in Rabi season, the groundwater is recharged except in the month of January (canal closure period) and March, depending on various irrigation and drainage factors, which are complex. Shallow groundwater quality was observed good and use able due to recharge by surface water. About 41 % of command area was under shallow water table with salinity of water 300-800 ppm, 29 % was under water quality of 800-1300 ppm, 9% was between 1800-2300 ppm and rest 12% of the area was observed more than 2300 ppm. The quality of fresh water pump lifting water from the depth of 40 ft was up to 2400 ppm and deeper pump water quality was about 25000 ppm in scavenger and saline tube wells. Average water table was about 3.0 ft and fluctuation was between 2.38-3.8 feet in spite of running the tube wells.(author)

[en] An attempt has been made to investigate the effect of post heat treatment of processes on torsional behavior of carbonized SAE 1020 steel, with 0.2 %-0.25% C, 0.6%-0.7% Mn, 0.15%-0.25% Si, 0.035% S, 0.035% P. All the specimens were heated up to 920 degree C temperature for fully austenitizing, and then different heating and cooling cycles were conducted just to alter the case core hardness. Hardness profile and Torque-Twist data was measured after different post heat treatments. It was found that with increasing 3.85% case hardness the torque efficiency also increased up to 55%, whereas no significant effect of core hardness on the torque has been revealed. (author)

[en] Thermal recovery is the most mature technology available for (EOR) Enhanced Oil Recovery). Thermal processes are either heat-injection processes or in-situ heat generation processes, and are particularly applicable to the recovery of heavy oils and tar sands. In-situ heat generation processes require combustion within the reservoir. These processes are categorized as either forward combustion, reverse combustion, or wet combustion. A high pressure disc type reactor has been used to study the effect of the main variables thought to affect the kinetics of heavy oil in a consolidated porous media on combustion. The processes observed were very dependent on the conditions used. The rate of oxygen consumption and carbon burning rate increased when the air flux is increased. This behavior is attributed to the overall increase in the rate of oxidation reactions. When the heating rate was reduced from 5 degree C min/sup -1/ to 1.5 degree C min/sup-1/ with constant inlet flux, LTO (Low Temperature Oxidation) reactions were found more significant. In addition, the rate of fuel burning reaction HTO (High Temperature Oxidation) decreased with decreased heating rate. The change in the rate of the fuel burning reaction is attributed to the change in the nature of the fuel burnt in a consolidated formation. (author)

[en] The miracle chip microprocessor represents a quantum leap in the technology of mankind, a development that over the past decade has acquired the significance in industrial automation and has led PCs to become workhorses in the everyday industrial environment. The communication of Microprocessor to the outside world depends upon the I/O devices and Interfacing Techniques. This work deals with the technique of interfacing Intel, Motorola, and Zilog processors, with their respective I/O devices (PPI, PIA, and PIO) for parallel data transfer. The PC based trainer is specifically designed to demonstrate how a particular microprocessor selects and initializes an I/O device, what hardware chips are necessary, what software instructions are used, and how various data transfers take place. Many practical exercises can be developed in software to expose students to more complex applications using PC-based Programmable Peripheral I/O Devices Trainer. (author)

[en] Holographic environment is based on high-equipped Multimedia information systems. These are based on the evolving powers of computers to handle huge volume of information. Holographic environment is a simulated environment that allows the user to touch and interact with projections, which are derived from the distant real environment. A new communications technology is being developed that will facilitate to interact inside a simulated environment, even if you are thousands of miles apart. This is done with enhancing the electro-holography, which is the computer based generation of diffraction fringes from 3D input data and the display of the reconstructed object in real-time. This research paper presents the design and development of holographic environment for reduction of distances in business and educational applications. The Holographic Environment development with the use of multimedia information systems is discussed. In Particular the characteristics of holographic data and the current research results in the area of real time holographic display systems are spanned. The Technical components of holographic system are also encountered. Finally, issues of improvement in efficiency of Holographic Environments by compression of data are presented along with its utilization for educational and business applications. (author)

[en] In this paper we present an architectural design and analysis of a programmable image processor, nicknamed Snake. The processor was designed with a high degree of parallelism to speed up a range of image processing operations. Data parallelism found in array processors has been included into the architecture of the proposed processor. The implementation of commonly used image processing algorithms and their performance evaluation are also discussed. The performance of Snake is also compared with other types of processor architectures. (author)

[en] Air pollution in Dhaka City has become an alarming issue in recent days. Unless necessary measures are taken for the abatement of air pollution, it is going to bring adverse consequences inhuman lives. The aim of this work is to measure air pollutants of different parts of Dhaka City and also to determine breathing air quality. The field experiments revealed the concentrations of RDP (Respirable Dust Particle) suspended in air, Nitrogen oxides (NO/sub x/) and Sulfur dioxides (So/sub 2/). A respirable dust sampler was employed to measure the concentrations of air pollutants. This work also covers an in depth study of types of air pollutants, sources, effects on human and materials and ways of controlling air pollution. This investigation is an endeavor to start a systematic collection of technical information with reliable chemical analysis using available equipment. (author)

[en] In order to examine the feasibility of wind energy for water pumping in Bangladesh, an experimental investigation of performance characteristics of horizontal axis wind turbines has been conducted. Wind characteristics of various regions of Bangladesh have been analysed and hence a compatible design of horizontal axis wind turbine applicable to the pump has been suggested. The wind data collected by the meteorological department of Bangladesh for a period 16 years of 20 stations at different heights between 5m and 10m have been converted to 20m hub-height using power law. From these data monthly average speeds have been calculated. It is observed that for few regions of Bangladesh, there is reasonable wind speed available throughout the year to extract useful power. Considering a particular prospective region of Bangladesh a wind turbine has been designed for water pumping. The design incorporates the generalized procedure for determination of rotor and pump sizes. Thus it can be also used for any other region as well. In this paper, a generalized design for Bangladesh, a nomogram and an empirical relation have been developed for the rotor and the pump size for a particular region of Bangladesh.(author)

[en] A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be proposed for different government agencies for the use of bridge designers. (author)