Applied Mechanics and Materials Vol. 575

Abstract: In this paper, an approach in predicting thickness of Titanium Aluminum Nitrite (TiN) coatings using Adaptive Network Based Fuzzy Inference System (ANFIS) is implemented. The TiN coatings were coated on tungsten carbide (WC) using Physical Vapor Deposition (PVD) magnetron sputtering process. The N₂ pressure, argon pressure and turntable speed were selected as the input parameters and the coating thickness as an output of the process. Response Surface Methodology (RSM) was used to design the matrix in collecting the experimental data. In the ANFIS structure, three bell shapes were used as input membership function (MFs). The collected experimental data was used to train the ANFIS model. Then, the ANFIS model was validated with confirmatory test data and compared with other prediction models in terms of the root mean square error (RMSE), residual error and prediction accuracy. The result indicated that the developed ANFIS model result was the lowest RMSE7 and average residual error, besides the highest in prediction accuracy compared to the other models. The result also indicated that the limited experimental data could be used in training the ANFIS model and resulting accurate predictive result.

Abstract: Insufficient and non-homogeneous secondary cooling in the semi-continuous casting has undesirable impact on mechanical properties of the product. The shortage of cooling leads to defects and surface cracks within the product.The discharge nozzles of cooling water have been changed to an annular slot. The annular slot ensures that water sprays entirely the surface of the strand. The new configuration verifies better competence and less maintenance requirements. The new casts show non-black surface, free-cracks surface, full straightness, and perfect microstructure.The speed of casting is increased by one-half times, that leads to superior productivity. In addition, higher casting speed leads to less metal losses. The maintenance efforts and time are reduced and the frequent nozzle shutting is avoided. The microstructure of copper is completely identical to the standard one. In addition, the microstructure of the leaded brass shows non-clustered Lead, this will avoid the hot tearing in the next processes.

Abstract: This work focussed on the optimisation of product yields from the pyrolysis of palm kernel shells (PKS). 479g of dried PKS were loaded into the retort and then placed inside the furnace chamber and this was pyrolysed at 300, 400, 500, 600 and 700°C. The pyrolysis products obtained are char, tar (pyro oil and pyroligneous acid) and gas. A full factorial design (FFD) consisting two factors (Temperature and duration of pyrolysis) at three level was used to study the pattern of product yields from the pyrolysis of PKS. Char, tar and gas were evaluated as the responses. Thirteen experimental runs resulted from the FFD with a minimum product yield of 0.9wt% and maximum product yield of 99wt%. Response surface methodology was used to analyse the results of the FFD of the product yields of PKS. The optimum conversion yields expressed as a percentage of oven-dried weight of palm kernel shells of char, tar and gas products at their respective pyrolysing temperatures were 99wt% char at 304°C, 35wt% tar at 700°C and 39% gas at 700°C. The duration for the pyrolysis process was 20mins for 479g of dried palm kernel shells. The results of the work show that palm kernel shells can be readily pyrolised to obtain optimum yield of gas, tar (mixture of pyrolitic oil and pyroligneous acid) and char.

Abstract: Wear is the main problem in gas turbine combustor components. The mating surfaces experience surface degradation affected by wear damage. The main mechanisms of wear occurred on combustor components could be adhesive wear, abrasive wear, and fretting wear. Wear resistant materials such as Haynes 25 (L605) and Stelitte 6 were selected to be used in reducing wear damage especially on bull horn, transition piece and flow sleeve of combustor components. The reduction of wear on combustor components can be described as the extension of combustion inspection interval of a gas turbine. It is concluded that wear on combustor components can be reduced by the applications of wear resistant materials on the components.

Abstract: Zirconia (ZrO₂) is used to fix restorations as a core material because of its mechanical properties, aesthetics, and compatibility. This study aims to analyze the failure types in ZrO₂-based restoration fabricated in a dental laboratory in Misurata, Libya. Data were collected from laboratory records for a 30-day period with follow-up for five months. About 6% of the total restorations had defects with different percentages, 46% of which were fractures, 29% of which had weak bonding between ZrO₂ frameworks and veneers, 18% of which had cracks, and 7% of which had shade defects. Although ZrO₂ is a suitable material for dental restorations, defects may occur and lead to the failure of dental restorations. A thorough study is necessary to analyze the cause of failurein zirconia-based restorationsand to improve the properties to produce a versatile dental restorative material.

Abstract: Chitosan is capable to form films which may replace non-biodegradable food packaging plastics. Chitosan films need to be plasticized to enhance its properties. Chitosan films were incorporated with brown seaweed by casting chitosan solution and brown seaweed solution on Petri dishes and heated at 55 °C. The surface morphology characteristic and mechanical properties were investigated. Surface morphology analysis of seaweed incorporated into chitosan film has resulted in a rougher film surface. Flocculation of seaweed extract in the chitosan film indicates that the seaweed has low miscibility with chitosan. The tensile strenght of chitosan seaweed film was recorded at the value below 8MPa with 20% of elongation, E. In contrast, the tensile strenght and elongation of pure chitosan films are recorded at 55 MPa and 60% respectively. Thus, this research has suggested that the incorporation of seaweed into chitosan film has lowered the value of the film properties.

Abstract: In this present work, the effects of phase inversion ceramic membranes prepared by phase inversion were investigated. Kaolin with 25µm was used as the composition of membrane preparation. The amounts of kaolin investigated were 60g, 70g and 80g respectively while the temperature was conducted assist room temperature and 3°C. Non-solvent additive with 6g distilled water present formation of pore during phase inversion.The effects of phase inversion temperature and kaolin composition on morphology and porosity were investigated in detail. Result of porosity showed that by decreasingphase inversion temperature improve the membrane porosity up to 64%. In addition, the FESEM images explained that membrane morphology obviously change with the effect of temperature during phase inversion process.

Abstract: In this research, green synthesis of silver nanoparticles using elaeis guineensis leaves extract was investigated and the effect of reaction time in reduction mechanism and particle size is studied. UV-visible sprectrophotometer was used to monitored the reduction reaction of silver ions to silver nanoparticles and formation of silver nanoparticles shown at 15 minutes. Transmission electron microscopy (TEM) and field emission scanning electron microcopy (FESEM) shows polydispersed and irregular shape of silver nanoparticles with aggregation. Further confirms the formation of silver nanoparticles by energy dispersive x-ray analysis (EDAX). From this research, it was found that the increasing reaction time increases the rate of reduction reaction of silver ions.

Abstract: Numerical model of one-dimensional steady-state on Alumina-Cordierite (Al-Co) open-celled foam using in transpiration cooling system have been conducted to investigate the local energy balance (LEB) of gas and solid phase within porous plate. Physical properties, i.e., porosity (f), pores per inch (PPI) and thickness (x), of Al-Co open-cellular porous material were 0.87, 13 and 0.103 m, respectively. Two equations of the conservative energy consisting of the gas and solid phase were analyzed. From study, it was found that heat convection (HVF) balanced with heat transfer between two phases/ energy of interaction (INT) for the gas phase case. In the solid phase, heat transfer between two phases (INT) tended to offset heat radiation (HRS). Remarkably, heat conduction of both phases (HDF and HDS) was not effected to the present cooling system. Thus, characteristic of fluid flow effecting by HVF and heat transfer governed from HRS was strongly efficient to transpiration cooling system.