Advanced Materials Research Vol. 701

Abstract: The electrochemical performance of Al-air cell employing seawater and NaCl electrolyte of various concentrations has been investigated. The open circuit voltage and discharge capacity of the cell correlate well with the electrolyte conductivity data. Using 4 M NaCl electrolyte which possesses the highest conductivity, the Al-air cell registers an open circuit potential (OCV) of 1.1 V and demonstrates discharge capacity of 250 mAh, rated at 1 mA. Upon employing seawater, the OCV reduced to 0.68 V and discharge capacity decreased to 150 mAh. However, utilizing an exposed cell configuration which mitigates the hydroxide gel water binding effect, the Al-air seawater cell performance is greatly enhanced until almost compatible to Al-air cell employing 4 M NaCl.

Abstract: This study investigates the effect of additive rice husk silica and Polyethylene glycol (PEG) on the performance of polysulfone (PSf) membrane. The membrane was prepared by phase inversion method using PSf, N-methyl-2-pyrrolidone (NMP) and rice husk silica was added as an additive. The performance of the membrane was analyzed by using distilled water for permeation test and humic acid for the rejection test. The result showed that the hydrophilic of PSf/PEG membrane has significantly improved the permeation and rejection performance with addition of rice husk silica. The results showed that with addition of 3% rice husk silica give the highest rejection flux at 196.63 L/m2hr with the rejection value 98%.

Abstract: The degradation of most of metals, with the exception of gold is a universal reaction. It is a constant and on-going problems, make it often difficult to eliminate completely causing either industrial or heritage conservation losing a lot of money. One way and most practical for corrosion protection are using green inhibitor. Therefore it is widely use either industry or heritage conservation. Unfortunately, the inhibitors used in conservation are frequently hazardous to conservator, either through inhaler or touch with skin. Responding to this, several researches has been conducted to look into environmental friendly inhibitors or green inhibitors. This paper will review current practice use of inhibitor in metal preservation before propose a new inhibitor which been used a long time ago in Malay traditional practice in Keris preservation.

Abstract: The rheological properties of feedstock for granulation process are important in controlling the parameters throughout the process. This study identifies the type of fluid that mixtures of Urea and Calcium Lignosulfonates (CaLS) possessed through the viscosity profiles using a parallel plate rheometer. The viscosity behavior of mixtures with varied weight percentages (wt %) of CaLS in urea solution were analysed. Results identified that the mixtures show shear thickening behavior of non-Newtonian fluid. It is also observed that the increases of CaLS content increase the viscosity of the mixtures. Moreover, the mixture with 50 % CaLS addition is found not suitable for further investigation as its viscosity is too high (3.450-6.773 Pa.s at zero shear rate) compared to molten urea (0.002 Pa.s).

Abstract: Geotextile is one of material in engineering field. In this research, nonwoven geotextile is used at road shoulder to flow clean water to the drainage system since it can act as a filter. The purpose of this research are to determine the ability of nonwoven geotextile as filter media and identify the quality of the filtered water before and after placing the nonwoven geotextile. Therefore, the road shoulder is designed to show the filtering process. Based on the JKR Manual On Pavement Design, a minimum thickness for soil and aggregate is 100 mm and each layer is compacted. However, the actual thickness is not being used because it is only to show the ability of nonwoven geotextile in filtering process and its consequence of using it. Two small scale models are created, first is with nonwoven geotextile and another one is without geotextile which aims to show the difference. Tank size 350 x 200 x 240 mm is used for placing material same as road shoulder such as nonwoven geotextile, sand, soil, and aggregates which form in three layers. Water was poured in the road shoulder model. Then the water sample flow out from the tank was tested in terms of level of turbidity and suspended solids contained in the water. Base on the results, it shows that the use of nonwoven geotextile can reduce almost 100% of suspended solid and turbidity of the water from flow into drainage system. As conclusion, the use of nonwoven geotextile at road shoulder can contribute positive impact to reduce the level of water pollution.

Abstract: Nowadays, formaldehyde is considered to be a hazardous volatile chemical. One of the formaldehyde sources is urea-formaldehyde resin which is mainly used as an adhesive in particleboard production. Hence, it is necessary to minimize the formaldehyde residue from urea-formaldehyde synthesis. This present work involves the kinetic modelling of urea-formaldehyde polymerization to predict formaldehyde concentration during the pre-polymerization process. On the basis of previous proposed mechanism, the kinetic model which accounted for the number of the functional groups on urea and formaldehyde and also reactive polymer chains was developed as a set of ordinary differential equations (ODEs). The formaldehyde concentrations from computer simulation results were compared with those from experimental investigation. Good agreement between simulation and experimental results was obtained. The developed kinetic model can be also applied to predict the functional group evolution during polymerization. This helps producers select the condition for production to minimize formaldehyde residue and predict the chemical structure of final product.

Abstract: The concentration of surfactant is usually determined by a colorimetric method. A simplified colorimetric method for determining cationic surfactant was proposed which has advantages over the existing colorimetric method where less chemical is used and the overall time to perform the analysis per sample is reduced by half. These methods were tested based on analyzing the ionic interaction of cationic surfactant-reactive orange 16 (PBE-RO16) mixtures. A linear correlation was observed between the absorbance ratio of PBE-RO16 mixture/dye and PBE concentration. Results obtained from this study shows that the error between the two methods is only about ±20% except for PBE concentration less than 20 mg/L. Therefore, the proposed simplified colorimetric method can be considered as an alternative method for determination of cationic surfactant in aqueous solution in the future.

Abstract: Wire electrical discharge machining (WEDM) is a material removal process of electrically conductive materials by the thermo-electric source of energy .This kind of machining extensively used in machining of materials with highly precision productivity. This work presents the machining of titanium alloy (TI-6AL-4V) using wire electro-discharge machining with brass wire diameter 0.25mm.The objective of this work is to study the influence of three machining parameters namely peak current (IP), feed rate (FC) and wire tension (WT) to material removal rate and surface roughness followed by suggesting the best operating parameters towards good surface finish. A full factorial experimental design was used with variation of peak current, feed rate and wire tension, with results evaluated using analysis of variance (ANOVA) techniques. Parameter levels were chosen based on best practice and results from preliminary testing. Main effects plots and percentage contribution ratios (PCR) are included for the main factors and their interactions. Peak current was shown to have the greatest effect on surface roughness (33% PCR).

Abstract: In the present work, effect of work material hardness and cutting parameters on chip-tool interface temperature was investigated during turning of AISI 4340 steel hardened at two different levels of hardness 35 and 45 HRC, respectively, using CVD applied multi-layer TiCN/Al₂O₃/TiN coated carbide inserts. A tool-work thermocouple principle was used to measure the interface temperature during turning. The correlation coefficient between experimental and predicted values of interface temperature found close to 0.95, which showed that the developed model is reliable and could be used effectively for predicting the interface temperature for the given tool and work material pair and within the domain of the cutting parameters. Experimental observations indicate that the interface temperature is higher for harder work material and get affected mostly by cutting speed followed by feed. However, depth of cut has little influence on interface temperature irrespective of the hardness of the workpiece.

Abstract: This paper and its companion (Part 2) deal with modelling and optimization of the flexible job-shop problem (FJSP). The FJSP is a generalised form of the classical job-shop problem (JSP) which allows an operation to be processed on several alternatives machines. To solve this NP-hard combinatorial problem, this paper proposes a customised Genetic Algorithm (GA) which uses an array of real numbers as chromosome representation so the proposed GA is called a real-coded GA (RCGA). The novel chromosome representation is designed to produces only feasible solutions which can be used to effectively explore the feasible search space. This first part of the papers focuses on the modelling of the problems and discusses how the novel chromosome representation can be decoded into a feasible solution. The second part will discuss genetic operators and the effectiveness of the RCGA to solve various test bed problems from literature.