BES Journal

Structural, Electrical and Galvanomagnetic Properties of InSb Thin Films Prepared by Vacuum Evaporation
Md. Abu Taher, Mithun Kumar Das, Mohammad Kamal Hossain and Osamu Nittono
InSb thin films with a thickness of about 3000 Å were prepared by employing both single and double-source vacuum evaporation methods, and their structures, morphology and electrical properties were investigated in terms of heat treatment procedures. From X-ray diffraction studies, the films were found to have polycrystalline structures. The formation ability of InSb compound was slightly lower for multilayer films than for single layer films. The electrical and galvanomagnetic properties were found to be related strongly to the structural properties as well as the crystallinity of the films. The maximum value of Hall mobility and magnetoresistance were calculated as 4.3x103cm2/Vs and 70%, respectively for the single layer films, while alternately stacked films showed 2.9x103 cm2/Vs and 29% for [Sb(2.5)/In(2.5)]60] multilayer films, and 3.1x103cm2/Vs and 10% for [Sb(150)/In(150)]1 bi-layer films, respectively.
tudy of Dielectric Constant of Raw and Low Temperature Plasma Treated Jute
Md. Masroor Anwer
Jute fibers, a cellulosic and environmentally friendly fiber are treated with low temperature Argon plasma for 5, 10, 15 and 20 minutes exposure times and at various discharge power levels of 50, 75 and 100 W. The dielectric constant (εr′) of both raw and low temperature Ar plasma treated jute as a function of frequency were studied at room temperature. It is observed that for all the samples the εr′ are almost constant at lower frequencies and then decreases gradually very sharply in the high frequencies region. In addition, εr′ increases with increase of plasma treatment times as well as discharge powers.
A Simple Method for Forming Metallic Micro Materials Utilizing Electromigration
Faizul Mohammad Kamal, Md. Nazrul Islam Khan and Faizul Mohammad Mohee
A technique for forming metallic micro materials by utilizing the electromigration method was proposed in this article. An aluminum line was formed on a titanium nitride layer covered with a silicon dioxide passivation layer. The corner hole was etched at the specimen using a sudden change in the area of the sample. The sample was placed on a ceramic heater under constant temperature, constant atmospheric pressure and constant direct current leading to the fabrication of micro and nano materials. Consequently, hillock at the corner hole was obtained in the silicon dioxide passivation and the aluminum layers. It was found that the location and the geometry of the corner hole significantly affected the formation of the micro and the nano materials.
An Online Shopping Store Management System
Dipto Dev and Md. Ismail Jabiullah
An online shopping store management system is designed and developed that permits a customer to submit online orders for items and/or services from a store that serves both walk-in customers and online customers. The online shopping system presents an online display of an order cut off time and an associated delivery window for items selected by the customer. The system accepts the customer's submission of a purchase order for the item in response to a time of submission being before the order cut off time. The online shopping system does not settle with a credit supplier of the customer until the item selected by the customer is picked from inventory but before it is delivered. Therefore, the customer can go online and make changes to the order. In addition, available service windows are presented to the customer as a function of customer selected order and service types and further, the order picking is assigned in accordance with a picker's preference. When ordering goods, many shopping systems provide a virtual shopping cart for holding items selected for purchase. Successive items selected for purchase are placed into the virtual shopping cart until a customer completes their shopping trip. Virtual shopping carts may be examined at any time, and their contents can be edited or deleted at the option of the customer. Once the customer decides to submit a purchase order, the customer may print the contents of the virtual shopping basket in order to obtain a hard copy record of the transaction.
Design of Micro-Strip Patch Antenna for Wi-Fi
Md. Sohag Mia, Md. Taslim Arefin, Md. Towfiqul Islam, Reja-E-Rabbi
his paper is focused on the design of Micro-strip patch antenna for Wi-Fi Router application. For Wi-Fi usage directional antenna with high gain and better coverage has been emphasized. A single and dual prove-fed patch antenna cut from a rectangular patch, having symmetric pattern of cross-slots has been designed in HFSS (High Frequency Structure simulation) Simulator. Experimental results for the micro-strip patch antenna over traditional patch antenna have been discussed in this paper.
Ground Response Spectra for Different Damping Values for 0.3g Peak Ground Acceleration Earthquake in Bangladesh
Faizul M. Mohee and Faizul M. Kamal
For the safety analysis of the buildings and structures of any nuclear power plant project, the variation of the acceleration with the frequency for different damping values and ground conditions need to be developed. This article presents the ground response spectra for different damping values between 1% and 10% for different types of ground conditions for an earthquake level of 0.3g peak ground acceleration (PGA) which covers all regions of Bangladesh. The variations of acceleration with frequency are presented along with the time history graph for the 0.3g PGA. The acceleration values increase with the decrease of the damping values for all types of ground conditions. The acceleration increases upto a certain frequency for a fixed damping, and then it decreases. The acceleration is higher in the steel structures (lower damping) compared to the reinforced concrete structures (higher damping). The curves are applicable for both the rock and the soil (overburden) conditions. Furthermore, the deflection of structures increases with the increase of the acceleration.
A Robust MAC Protocol Featuring Fast Handover and Dynamic Bandwidth Allocation for Road Vehicle Communication Systems
Md. Zahirul Islam, Mahmudul Hasan, Sirajum Munira
In this paper, a robust MAC protocol for Radio over Fiber Road Vehicle Communication (RoF RVC) systems featuring fast handover and dynamic bandwidth allocation has been proposed. The Road Vehicle Communication (RVC) system is an intelligent transportation systems (ITS) based infrastructure network can be implemented along the road. The system supports voice, data as well as real-time video under high mobility conditions. Bandwidth management schemes have also been proposed that are differentiated in accordance with their capability to change VCZ size (i.e. the number of cells covered by the VCZ) to adaptively change the bandwidth reserved for handover requests. Study suggests that the scheme with the ability to change VCZ size is efficient in bandwidth usage. In addition, when it is combined with a conventional adaptive bandwidth reservation algorithm, handover quality will also improve.
Design of a Low-cost Solar Tracking Control System for an Optical Sensor-based Photovoltaic System using Microcontroller
S. M. Mostafa Al Mamun, Fatima Nafisa Chowdhury, Md. Abdullah Al Mamun and Md. Atiar Rahman
This paper presents a prototype model of a microcontroller based automatic dual axis sun tracking system. This is a low-cost system design which increases the efficiency of the solar power generating equipment by automatically getting the maximum sunlight using a simple sensor array model. The main objective of a solar tracker is to maximize the amount of captured solar energy by orienting a solar photovoltaic (PV) panel towards the sun. In order to attain a high degree of tracking accuracy, many different approaches have been broadly investigated. Open-loop (mathematical models) and closed-loop (sensor based) tracking system are widely used for sun tracking. In this paper a closed-loop design of a dual-axis solar tracking PV system is proposed which utilizes a simple electronic circuit to provide vigorous system performance using ATmega8 microcontroller along with a four light dependent resistor (LDR) sensors. The control implementation is a technical innovation that is a simple and effective design. The designed system is tested in laboratory to confirm its effectiveness.
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