http://hdl.handle.net/10361/37 Sun, 19 May 2013 01:25:12 GMT 2013-05-19T01:25:12Z http://hdl.handle.net/10361/1802 A comparative study on dispersivity of Arsenic among Surma, Sari and Volaganj sand Islam, Shriful; Rahman, M.S.; Das, R.K. Transport mechanism of Arsenic (As) through the Surma, Sari and Volaganj sand is the prime concern of this study. Three column leaching tests were performed to find the dispersivity property of As. Numerous physical properties of these sand samples were determined and it shows Volaganj sand is most permeable. From the collected data experimental and theoretical breakthrough curve (BTC) were prepared and compared with each other. The value of dispersion coefficient and Index of dispersion were calculated. Dispersion coefficient (773.763cm2/min) and index of dispersion (844.3cm2/min) was higher for Surma sand. The leaching rate was found higher for higher pore water velocity of the Volaganj sand. The study also reveals that there is a significant difference between theoretical and experimental breakthrough curve. So not only convection/dispersion but also other processes such as adsorption, reaction with other compound are associated with the movement of arsenic through the sand medium. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10361/1802 2011-01-01T00:00:00Z http://hdl.handle.net/10361/1801 Use of Mustard oil as an alternative and renewable substitute of Fossil diesel Hasib, Z.M.; Rahman, K.A.; Alam, M.M. Energy is the prerequisite for modern civilization. Fossil fuel is still the main source of energy. But the endless consumption of fossil fuel has brought its reserve about to an end. As a result, fuel prices are growing as a consequence of spiraling demand and diminishing supply. So we are always in search of alternative and cost effective fuels, to meet our need. Diesel engines are more efficient and costeffective than other engines. So diesel engines have versatile uses (i.e. automobiles, irrigation, power plants etc.). That is why; consumption of diesel fuel is much higher than other gasoline fuels. This paper estimates the feasibility of mustard oil as an alternative fuel for diesel engine. Mustard is a renewable plant, widely growing in almost everywhere in Bangladesh. In this study, mustard oil is converted to bio-diesel by well known trans-esterification reaction. Bio-diesel has different fuel properties than diesel fuel. So other than modification of the engine or the fuel supply system, blends of bio-diesel (i.e. B20, B30, B50 etc,) has been used. Finally, a comparison of engine performance for different blends of bio-diesel has been carried out to choose the correct blend for different operating conditions. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10361/1801 2011-01-01T00:00:00Z http://hdl.handle.net/10361/1800 Unplanned urbanization and hill cutting: a study on environmental change in sylhet Rahman, Md. Habibur Bangladesh is a developing country having diversified environmental issues especially in the city area. The present study was conducted in Sylhet City Corporation; one of the rapidly developing urban areas in the north-eastern region of Bangladesh to identify the main environmental problems due to rapidly increase population, unplanned urbanization and hill cutting. The major environmental problems in the city are traffic obstruction, inappropriate solid waste disposal system, inadequate water supply, water logging state, hill cutting, chance of seismicity, etc. The nature and life style of Sylhet intimately related with the hills are thus under the threat of a drastic imbalance in its ecosystem. This study also investigates the causes of hill cutting along with its probable impact on environment such as deforestation, loss of biodiversity, ecological imbalance and climatic change, chances of earthquake will increase, destroying natural beauty, soil erosion and landslide, etc. Sylhet is located in highly seismic risk zone 3 but most of the buildings and apartments are constructed without considering earthquake risk. The City Corporation authority should take a new approach to tackle urban problems by investing new ways to solve them, taking advantages of unused resources and opportunities. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10361/1800 2011-01-01T00:00:00Z http://hdl.handle.net/10361/1799 Estimating money demand function of Bangladesh Alam Miah, Md. Habibul Although money demand equations have been estimated for many western countries, yet only recently many researchers have investigated the demand for money in mixed economies like Bangladesh. Co-integration technique is now a common method of estimating any money demand function. This paper empirically analyses the stability of the narrow and broad money demand functions (M1, M2, and M3) in Bangladesh for the period 1999QI-2005QIIII. To determine whether the policy framework satisfies the necessary condition for effectiveness of monetary policy, the stability of Bangladeshi M1, M2, and M3 money demand is estimated and tested by employing a recent co-integration procedure proposed by Johansen-Juselius (2001). It is shown that even though M1 and M2 monetary aggregates are co-integrated with income, interest rate and nominal effective exchange rate, application of Cumulative Sum (CUSUM) and Cumulative Sum of Square (CUSUMSQ) tests to the residuals of an error-correction model reveal that it is unstable. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10361/1799 2011-01-01T00:00:00Z