Materials Science Forum Vol. 1034

Abstract: The use of the periwinkle shell in the production of lightweight concrete has been studied and accepted to be used for concrete works. Hard water containing detergent-like chemicals has been observed to be used in mixing locally produced concrete. This exploratory study is on the effect of water mixed with detergent in a concrete prepared with the periwinkle shell as a coarse aggregate. A total of 27 concrete cubes of size 150mmx150mmx150mm were prepared in the laboratory with a mix ratio of 1:2:4. A water-cement ratio of 0.4 was used with the addition of detergent at varying percentages (0%, 0.3% and 0.6). The cubes were cured in water and tested at 7days, 14days and 28days respectively. Laboratory tests, which includes bulk density, specific gravity, grain size analysis, slump and the compressive strength test was carried out on the aggregates and concrete. The periwinkle shell had a bulk density of 1440kg/m³and a specific gravity of 2.50. The workability tested revealed that the slump values increased with increase in the percentages of detergent. The compressive strength at 28days and at 0.3% and 0.6% were 12.58N/mm² and 14.06N/mm² respectively. It was observed that the compressive strength decreased with the addition of detergent because of the tiny air bubbles introduced into the concrete by the detergent. From the results of the study, it can safely be concluded that the use of detergent contaminated water in concrete production will reduce its compressive strength and increase its workability.

Abstract: Staircase is a very important structural element found in mostly buildings of more than a floor. The properties of materials and designs used in constructing this structural element are very important. This study addresses the development of ultra-lightweight concrete. How ultra-lightweight concrete can effectively work in helicoidal structure. The flexural strength of this staircase was analysed on a finite element software SCAD. The designed lightweight aggregates concrete is targeted to be used in staircase of a structure having the shape of helicoid. In the concrete, chopped basalt fiber portion was added to each concrete mixture specimen reinforced as reinforcement. The basalt fiber percentages used are 0, 0.45, 0.9, 1.2 and 1.6. The developed lightweight expanded clay basalt fiber concrete showed significant increase in the flexural strength. The loads applied on this helicoidal concrete staircase in SCAD were derived from the laboratory experiments conducted on the concrete specimens on the 28 days curing period. This combination of values exceeds, to the researchers' knowledge, the performance of all other lightweight building materials. Furthermore, the developed lightweight concrete possesses excellent durability properties.

Abstract: Two-dimensional lattices are widely used in many engineering applications. If 2D lattices have large numbers of unit cells, they can be accurately modeled as 2D homogeneous solids having effective material properties. When the slenderness ratios of struts in these 2D lattices are low, the effects of shear deformation on the values of the effective material properties can be significant. This study aims to investigate the effects of shear deformation on the effective material properties of 2D lattices with hexagonal unit cells, by using the homogenization method based on equivalent strain energy. Several topologies of hexagonal unit cells and several slenderness ratios of struts are considered. The effects of struts’ shear deformation on the effective material properties are examined by comparing the results of the present study, in which shear deformation is neglected, with those from the literature, in which shear deformation is included.

Abstract: Biomass is a source of alternative energy that is environmentally friendly and very promising as one of the sources of renewable energy at present. The best candidate for the biomass waste for pyrolysis raw material is sugarcane bagasse. The sugarcane bagasse is a fibrous residue that is produced after crushing sugarcane for its extraction. Sugarcane bagasse is very potential to produce bio-oil through a pyrolysis process. The advantage of utilizing sugarcane bagasse is to reduce the amount of waste volume. Pyrolysis is a simple thermochemical conversion that transforms biomass with the near absence of absence of oxygen to produce fuel. Experiments were carried out on the fixed bed reactor. The analysis was carried out over a temperature range of 300-500 °C under atmospheric conditions. Products that are usually obtained from the pyrolysis process are bio-oil, char, and gas. Product analysis was performed using Gas Chromatography (GC) and Mass Spectrometry (MS) analysis. This research is aimed to study the kinetics of the sugarcane bagasse pyrolysis process to produce bio-oil. Three different models were proposed for the kinetic study and it was found that model III gave the best prediction on the calculation of pyrolysis process. From the calculation results, kinetic parameters which include activation energy (E_a) and the k factor (A) at a temperature of 300 °C is 2.4730 kJ/mol and 0.000335 s^-1, at a temperature of 400 °C is 3, 2718 kJ/mol and 0.000563 s^-1, and at a temperature of 500 °C is 4.8942 kJ/mol and 0.0009 s^-1.

Abstract: The quality of the friction stir processed (FSPed) depends on the proper combination of processing parameters. The proper combination can only be found when a series of experiments have been conducted. However, the Taguchi technique was developed as a way of reducing numerous experiments that are time-consuming and costly. This paper reports on the optimization of parameters for the FSP that is conducted underwater (SFSP) and room temperature (NFSP). The Taguchi L18 method was employed in the design of experiments. The four factors used for the analysis had three factors with three-levels and one with two levels. The parameter combinations for SFSP were different from the combination found for NFSP. The level of parameter sensitivity was found to be influenced by the processing condition.