Volume: 2
Number: 1
January-June 2003

To see an article directly, click its Title. To see abstract, click its [Abstract] link.

• SCRIPTING COMPLEX ARIDTHMETIC IN A WEB APPLICATION: MICROWAVE ENGINEERING SOLUTIONS
  ANM Shariful Islam, Robert M. Nelson
  Abstract PDF
  SCRIPTING COMPLEX ARIDTHMETIC IN A WEB APPLICATION: MICROWAVE ENGINEERING SOLUTIONS
  ANM Shariful Islam, Robert M. Nelson

  Abstract

  Many aspects of microwave engineering involve detailed calculations. To allow students to focus on fundamental concepts rather than mathematical operations a web-based design tool named “Microwave Engineering Solutions" (MES) was developed as a graduate student project in the Electrical and Computer Engineering Department at North Dakota State University (NDSU), USA. Most of the programming code used in MES was written in JavaScript. Although JavaScript has many positive attributes, it is not capable of performing many of the complex mathematical operations often needed in microwave engineering. To overcome the limitations of JavaScript, server-side programming languages like PHP and Perl were used. In addition, some of the complicated mathematical equations were written in a form that could be handled by JavaScript. In this paper, a brief description of MES and its component tools is provided. This is followed by a discussion of many of the programming aspects involved in MES. MES is used by ECE students studying various aspects of electromagnetic and is freely available on the web http://venus.ece.ndsu.nodak.edu/~ronelson/mes/index.html
• COPYRIGHT PROTETION OF IMAGES BASED ON FREQUENCY (DCT)TECHNISQUES
  M.A. Matin, S. Datta
  Abstract PDF
  COPYRIGHT PROTETION OF IMAGES BASED ON FREQUENCY (DCT)TECHNISQUES
  M.A. Matin, S. Datta

  Abstract

  Recently, a mass of multimedia data can be rapidly produced and transmitted using modern digital technologies. Naturally, solutions to digital copyright protection are required urgently to tackle the problem of unauthorized copying and distribution. The aim of this paper is concerned with inserting copyright information into host image. Specifically, we introduce an approach of frequency domain technique to secure robust watermarking for copyright protection. Robustness of the watermarking scheme is studied in defending alterations such as filtering, lossy compression, and other attacks.
• FLUIDIZATION BEHAVIOR OF SOLID PARTICLES FAST PYROLYSIS REACTOR FOR THERMOCHEMICAL CONVERSION OF BIOMASS SOLID WASTES
  Mohammad Rofiqul Islam, Mohammad Mahmudul Hasan, Bijoy Kumer Sarker
  Abstract PDF
  FLUIDIZATION BEHAVIOR OF SOLID PARTICLES FAST PYROLYSIS REACTOR FOR THERMOCHEMICAL CONVERSION OF BIOMASS SOLID WASTES
  Mohammad Rofiqul Islam, Mohammad Mahmudul Hasan, Bijoy Kumer Sarker

  Abstract

  Among various methods of thermochemical conversion of organic solid wastes into biocrude, fluidized bed pyrolysis system has attained much attention. In this study one cylindrical cold model fluidized bed reactor has been constructed from fiberglass pipe. Different tuyere-type gas distributors of 6, 9 and 12 standpipes, with 4 holes on each pipe have been fabricated. The river sand of different particle sizes has been used as bed material. The fluidizing gas was dry air, supplied by a compressor. The airflow rate and pressure drop across the beds of different height were measured. From this study optimum values of fluidization parameters in a fast pyrolysis reactor: bed particle size, bed height, minimum fluidizing velocity, bed particle entrainment and elutriation, behavior of solid mixing and suitable distributor plate have been found out. From the experimental results a mathematical model has been developed. The results obtained by the cylindrical model are compared with the relevant work and those from the mathematical model. These values of the parameters are proposed to design and fabricate a laboratory scale fluidized bed pyrolysis reactor to convert biomass solid wastes into pyrolysis liquid oil, which may be used as an alternative fuel.
• HEAT TRANSFER IN FORCED CONVECTION THROUGH SQUARE DUCTS
  R.K. Khan, Ali M.A.T, M.A.R. Akhanda
  Abstract PDF
  HEAT TRANSFER IN FORCED CONVECTION THROUGH SQUARE DUCTS
  R.K. Khan, Ali M.A.T, M.A.R. Akhanda

  Abstract

  This paper presents an experimental study to investigate the heat transfer characteristics and friction factor in developing turbulent flow through a ribbed square duct and a non-ribbed square duct. The ducts are made of 16mm thick bakelite sheet. The bottom surface of the ribbed wall has rib pitch to height ratio of 6. Both of the non-ribbed and ribbed ducts are heated by passing alternating current to the heater placed under them. The constant heating is controlled using a digital temperature controller and a variac. The results of ribbed duct are compared to the results of the non-ribbed duct under the similar experimental conditions. It is found that the heat transfer in ribbed duct is better than the non-ribbed duct. It is also evident that in the ribbed duct Nusselt number increases by 19.68 percent and mean friction factor increases by 7.68 percent over that of the non-ribbed duct.
• ASSESSING SURFACE FORM OF EXPANDABLE POLYSTYRENE SHEET DURING HOTWIRE CUTTING
  Riza Sulaiman
  Abstract PDF
  ASSESSING SURFACE FORM OF EXPANDABLE POLYSTYRENE SHEET DURING HOTWIRE CUTTING
  Riza Sulaiman

  Abstract

  Production of foam materials, such as expandable polystyrene, has been growing rapidly throughout the world as they have variety of uses. Some examples are in automotives industries, food packaging industries, medical application, sports gears, home insulations, and floatation in offshore drilling rigs, buoys and small boats. Since the uses of foam effects greatly to the daily lives of humans, the need to have foams in different shapes requires speed in cutting and speed in manufacture. This can only be done through computer-aided cutting machines or automated-cutting of foams. However, the speed of cutting will affect the surface finish or surface form of the cut. Therefore, it is necessary to determine the surface form of the polystyrene to achieve quality results. This is an on-going research to produce a rapid-prototyping machine, which cuts foam models. This paper illustrates the First Phase of this research, which is to determine the surface form of polystyrene through the use of Coordinate Measurement Machine (CMM), after being cut with different types of hot-wires, variable temperatures and diverse cutting speed.