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Biocementaion, a promising soil improvement technique, mostly utilizes calcium chloride (CaCl2) as its calcium source. However, using CaCl2 poses a critical environmental problem of producing ammonium chloride as a by-product. Alternatively, when calcium acetate (Ca(CH3COO)2) is used as the calcium source, the production of ammonium chloride during biocementation can be reduced. Ca(CH3COO)2 can be easily derived from waste eggshells. Nevertheless, such research has been conducted only with Microbial Induced Carbonate Precipitation (MICP) to date. This paper aims to study the implementation of eggshell Ca(CH3COO)2 in the more effective biocementation approach: Enzyme Induced Carbonate Precipitation (EICP) via soybean urease. For this study, EICP solutions of varying molar ratios and concentrations were studied for their precipitation efficiency and reinforcement effect on poorly graded sandy soil. The findings showed that the EICP solution composition of 1:1 molar ratio between Ca(CH3COO)2 and urea, added with 50 g/L soybean solution reached the maximum precipitation efficiency. It also produced the highest 7-day UCS of 371 kPa at a calcium carbonate content of 0.40%. Furthermore, the eggshell-soybean EICP produced 8.5% higher UCS than CaCl2-soybean EICP despite having similar calcium carbonate content.

In this talk we have applied an enhanced (G'/G)-expansion method to find the traveling wave solutions of the (2 + 1)-dimensional Zoomeron equation. The efficiency of this method for finding the exact solutions has been demonstrated. As a result, a set of exact solutions are derived, which can be expressed by the hyperbolic and trigonometric functions involving several parameters. When these parameters are taken as special values, the solitary wave solutions and the periodic wave solutions have been originated from the exact solutions. It has been shown that this method is effective and can be used for many other nonlinear evolution equations (NLEEs) in mathematical physics. [ABSTRACT FROM AUTHOR]

Biomass is one of the predominant renewable energy sources and the use of biomass for the energy generation has got much attention due to its environmental friendliness. Densification of coir dust into fuel briquette can solve waste disposal problem as well as can serve as an alternative energy source. The objective of this study was to investigate the possibility of producing briquette from coir dust and rice husk blend without binder. During this study, a briquetting experiment was conducted with different coir dust and rice husk blends (i.e. coir dust and rice husk ratio of 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100). Briquetting operation was performed using a die-screw press type briquetting machine. The briquettes were tested to evaluate their density, compressive strength, calorific value, burning rate and water vaporizing capacity and it was found that mixing ratio had a significant effect on the physical, mechanical and combustion properties of the coir dust-rice husk briquettes. Density, compressive strength and calorific value and water vaporizing capacity were increased with increasing mixing ratio while burning rate was decreased. Coir dust-rice husk briquettes with mixing ratio of 20:80 had higher density (1.413 g/cm³), compressive strength (218.4 N/cm²), calorific value (4879 kcal/kg), water vaporizing capacity (0.853 l/kg) and low burning rate (0.783 kg/hour) followed by the mixing ratio 40:60, 50:50, 60:40 and 0:100. The results indicate that coir dust and rice husk blend briquettes were found to have better overall handling characteristics over rice husk briquette. However, production of briquettes from coir dust and rice husk at mixing ratio of 50:50 was found to be more suitable for commercial application in terms of cost effectiveness. [ABSTRACT FROM AUTHOR]

Peat is an unconsolidated deposit of semi-carbonized plant matter. Peat is usually found in water-saturated environments and has certainly high moisture content. Haors are peat-dominated areas in Bangladesh, which hold the largest peat reserves of the country. Peat is one of the most important mineral resources worldwide. For the utilization of peat similar to other countries, it is necessary to know its energy and fertility potential and develop a sustainable management strategy for peatlands in Bangladesh. This study mainly focused on the heating and fertility potentials of peat in Bangladesh and on strategies to sustainably manage these peatlands. This study was carried out in the haor-based Katiadi and Mohanganj upazilas in the Kishoreganj and Netrokona districts of Bangladesh, respectively. These two haor areas are appropriate for collection of peat samples and people in those areas use peat as fuel and fertilizer. After peat samples were collected, they were tested in several laboratories such as the Agrivarsity Humboldt Soil Testing Laboratory of the Bangladesh Agricultural University (BAU) and Institute of Fuel Research and Development (IFRD), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, Bangladesh. These laboratories are suitable to find out the physical and chemical properties of peat. Based on the physical and chemical analysis of the collected peat, it has heating and organic fertility potentials. In this study, the pH; organic matter; N, P, K, and S contents of the peat were analyzed. The calorific value of peat (2638 kcalkg-1) is higher than that of cow dungs (1797 kcalkg-1) and rice husk briquettes (2546 kcalkg-1). Minor-scale rural haor communities use peat as domestic cooking fuel and supply for small agrofarms. In some agrofarms, ingredients, such as animal manure, are mixed with the peat to balance organic fertilizer. Our analysis indicates that peat might be used for different purposes, especially for brick fields, which reduces deforestation and saves the environment. The Government of Bangladesh should design a major peat development program to determine systematic approaches for the sustainable use of peat and peatlands in Bangladesh. [ABSTRACT FROM AUTHOR]