This paper reports the results of the investigation done on bricks made using BOTTOM ASH and fly ASH. Bricks were made with various proportions of BOTTOM ASH, fly ASH and cement. Tests for workability, density, strength, water absorption and ultrasonic pulse velocity (UPV) were conducted. Results show that the compressive strength ranged from 5.5 MPa to 11.68 MPa, maximum water absorption was 15.7% and the UPV ranging from 2260.2 m/s to 2916.1 m/s. The strength of bricks increases with the increase in fly ASH; water absorption, and UPV with the increase in fly ASH. It is concluded that bricks of good quality can be made using BOTTOM ASH and fly ASH whereby contributing to sustainable development.

Dear Editor-in-ChiefThailand produces about 10 million tonnes of ASH as solid waste which comprises of fly ASH (FA), BOTTOM ASH (BA) and other incineration power plant residues (1). Since 2000, the incineration residues have been promoted in Thailand, ac-cording to the information from the Government of Thailand. “ Utilization of incineration residues can provide environmental benefits by decreasing the need for landfill and reducing raw material extraction” (2, 3).....

This paper presents the experimental investigations carried out to study the effect of use of BOTTOM ASH (the coarser material, which falls into furnace BOTTOM in modern large thermal power plants and constitute about 20% of total ASH content of the coal fed in the boilers) as a replacement of fine aggregates. The various strength properties studied consist of compressive strength, flexural strength and splitting tensile strength. The strength development for various percentages (0-50%) replacement of fine aggregates with BOTTOM ASH can easily be equated to the strength development of normal concrete at various ages.

This research examined the utilization of BOTTOM ASH mixed with silica fume in the ground improvement technique by constructing columns beneath the soft clay. Utilizing the BOTTOM ASH was an effective method and easily available in the market and the application of silica fume in the study improved the result through its pozzolanic characteristics. The vibro-replacement method was implemented during the BOTTOM ASH column installation process. The properties of the materials involved in the research were examined by suitable geotechnical tests complying with relevant standards. The important parameter, shear strength was accessed by conducting the Unconfined Compression Test (UCT). In this study, a total of seven (7) batches of soil samples were involved comprising the control sample. From each batch, it had five (5) soil samples which included the 14 mm and 20 mm diameter of column with the height of 60 mm, 80 mm, and 100 mm. From the results of shear strength improvement, the 14 mm diameter column with height penetrating ratios of 0.6, 0.8, and 1.0 were showing 58.97%, 88.56%, and 69.81% respectively. The next column design which had the 20 mm diameter with the height penetrating ratio of 0.8, recorded the highest improvement of 38.73%, followed by 1.0 and 0.6 which resulted in 32.81% and 19.19% respectively. The use of correlation technique had streamlined the complexity of the independent variables and verified the reliability of the results through the R2 value. In summary, the improvement in shear strength was significantly influenced by the column design.

Nowadays, optimization is becoming one of the most important techniques in engineering and industry to provide competing products in design and manufacturing. Therefore, it is a necessity to search for optimum designs with productibility. In aerospace industry reducing weight and improving reliability of the products are major concerns. As regards the gearbox is one of the most important parts in the helicopter propulsion system, these objects should be more considered. However, most of the existing designs consider only one object, hence, it is vital to implement optimization techniques to include different objectives to improve the existing designs and provide optimum products. In this paper, optimum design parameters including module and face width of gears for the main gearbox of Sikorsky ASH-3D helicopter have been determined (modified) using single and multi-objective mixed discrete- continuous optimization method to minimize weight of the gearbox, increase the safety factor and reduce the difference between safety factors of different gears. The results show that the weight of the gears can be reduced by 27.24% comparing with the existing gearbox. The results of the multiobjective optimization have also been presented as Pareto front diagram wich can be used by the manufacturers to satisfy the prefered requiments.