Waste cooking oil (WCO) is typically cheaper than diesel and has much less impact on food-chain, so its use as biodiesel can reduce the cost of diesel run operations. Air-conditioned fast food restaurants (FFR) in Bangladesh generate lot of WCO, but due to frequent load shedding they also need to burn lot of diesel for captive power generation. Recycling part of the waste oils in the form of biodiesel can reduce the need of diesel fuel and increase profitability of the establishment. The techno-economic feasibility of such operation in case of a FFR in Dhaka has been investigated. CH 3 OH (methanol) and NaOH (sodium hydroxide) as base catalyst are mostly used in this process because of their lowest costs, higher reaction rates and higher yields. From the WCO generation of about 80 lites per week, yield for biodiesel production is considered in the range of 80-90%. Single-stage transesterification (SST) process is the cheapest and the easiest of the different methods. The cost of chemicals can be further minimized by recycling of CH 3 OH and NaOH in this SST process. The possible 35-40% CH 3 OH and 80-90% NaOH recoveries were considered for a alcohol to oil molar ratio of 5:1 of the reactants. It is found from the study that a small scale processing plant could be developed with reactant recovery units for producing biodiesel to supplement diesel fuel needed to run the generators. The monthly savings was equivalent to only 4% of the diesel cost for standby power, with a payback period of about one year. However this can increase up to 50% of the fuel cost and less than six months of payback period if the cost of dumping WCO in considered. The study reveals that even in the case of a FFR where WCO is available at almost no cost, the processing cost for biodiesel does not make it very feasible unless the cost associated with properly dumping the WCO is high enough.

The aim of this study was to investigate the prevalence of Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) strains and to identify the stx gene types in wild captive and companion birds. In total,657 E. coli isolates from 219 birds belonging to 38 different species were investigated for the presence of STEC and EPEC strains. It was shown that five birds (2.28%) carried strains positive for one or more of the virulence factors investigated. The results indicated that 1.8% (n=4) and 0.45% (n=1) of the birds carried STEC and EPEC strains, respectively. All STEC strains harbored the stx2f and eae genes and this finding reveals the role of other birds, in addition to pigeons, as reservoirs of STEC. The only EPEC strain in this study was isolated from a Myna. Based on our knowledge, this is the first report of Stx2f-producing STEC in Geese, Duck and Lesser kestrel. In conclusion, the results indicate a low frequency of STEC carriage in wild and companion birds, and point out the need of additionally screening for the presence of stx2f in all the eae-harboring strains from birds.

Petrol engines can run on natural gas, with little modification. The combustion characteristics of natural gas is different from that of petrol, which eventually affects the engine performance. The performance of a typical automotive engine was studied running on natural gas, firstly at a constant speed for various loads and then at a constant load for a range of speeds and results were compared with performance using petrol. Variation of the spark advance, consisting of centrifugal and vacuum advance mechanisms, was investigated. Results showed some reduction in power and slight fall of efficiency and higher exhaust temperature, for natural gas. The air-fuel ratio for optimum performance was higher for gas than for petrol. This variation in spark requirement is mainly due to the slower speed of flame propagation for natural gas. For both the cases, the best power spark advance for natural gas was found to have higher values than petrol. This issue needs to be addressed during retrofitting petrol engines for running on natural gas.

A clean-burning cooking stove that also generates electricity (The Score-Stove TM ) was modified to enable evaluations to take place in 3 regions of Bangladesh. Using the principle of thermo-acoustics to generate electricity it can supply power for applications such as -LED lighting, mobile phone charging and radios particularly in rural areas without grid electricity. After assessing the needs of the rural communities through a survey, tea-stalls and small restaurants owners were identified as people with the most potential of using the Stove in Bangladesh. The Bangladesh University of Engineering and Technology ((BUET) modified a Score-Stove to use both wood and a pressurised kerosene burner of a design that is widely used for cooking in rural areas of Bangladesh. The design was adapted to meet performance needs such as: heating rate, cooking efficiency, energy distribution, electric power generation, exhaust emissions and time taken to boil water using standardised water boiling tests. Performance was also compared with conventional (non-electrically generating) stoves that use a pressurised kerosene burner. A stove suitable to be demonstrated was developed to obtain feedback from some end-users for evaluation. Effects of the technical changes to the stove required for field trials and laboratory experimental results are presented. Technical deficiencies are documented and recommendations for improvements and future research in order to obtain wider end-user acceptance are made.

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