Key Engineering Materials Vols. 594-595

Abstract: Fossil fuel is one of the main energy sources for almost all country in the world. However, it is non-renewable energy source, not environmental friendly and the limited supply of the fossil fuel encouraged the scientist to discover other alternative way of new renewable energy supply. New alternative source should be considered for prolonged lifetime. Thus, non-conventional energy sources should be placed in the prior consideration, for instant bioethanol. Jatropha curcas seed is a toxic substance; however, it has a very high oil content which is approximately 3545%. After the extraction of oil from the seed, Jatropha seed cake is formed. In the pressed seed cake, it is found that it contains cellulose and glucose that can be used as substrate in bioethanol production. The production of bioethanol can be estimated by neural network using data from previous research. A programme using MATLAB 7.8 was used to develop the neural network. The software consists of Neural Network Toolbox which functions to train the input data and estimate the production of glucose and bioethanol as output data. An input layer represents the criteria of the production properties of glucose and bioethanol concentration. The hidden layer determines either the input data can be proceed to further production of glucose and bioethanol, whereas the output layer gives the estimation values of glucose and bioethanol production. Back propagation algorithm with TANSIG transfer function was used to accomplish the estimation of production of bioethanol. The error value given by the network was 0.0390. Thus, training sessions were considered successful. Therefore, the users could determine and estimate the production of glucose and bioethanol concentration in just a short period of time.

Abstract: This paper presents the study of carbon powder as additive in near-net-shaping of mechanical components through warm forming route. Three design parameters, i.e., carbon content (wt %), forming temperature, and sintering schedule were investigated. Iron powder ASC 100.29 was mechanically mixed with different wt% of carbon and copper powder for 30 minutes to prepare the feedstock. Green compacts were then formed through uni-axial die compaction process at 30°C and 180oC. The defect-free green compacts were then sintered at 1000oC in an argon gas fired furnace at a heating/cooling rate of 5oC/minute for 30, 60, and 90 minutes, respectively. The green samples as well the sintered products were characterized through relative density measurement, radial shrinkage, and microstructure evaluation. The results revealed that excessive carbon content contributed adverse effect to the final quality of the products.

Abstract: In this work, density and viscosity of ionic liquids with dicynamide and thiocyanate anion were obtained. The thermal expansion coefficient values were obtained from the experimental density values. The density and viscosity of the ionic liquids depends on the nature of the cations. The density of the ionic liquids increases in the order of [BMIM]⁺ < [AMI⁺ < [BzMI⁺ < [HEMI⁺ for dicynamide anion. Both for thiocyanate and dicynamide anions the viscosity values increase in the order of [BMI⁺ < [AMI⁺ < [BMI⁺ < [HEMI⁺. Moreover, viscosity values of ionic liquids with dicynamide anions are less than their corresponding thiocyanate anion.

Abstract: The codoped ZnO thin film were deposited by DC magnetron sputtering on silicon (111) followed by annealing treatment at 400 °C and 600 °C for 1 hour in nitrogen and oxygen gas mixture. Structural investigation was carried out by scanning electron microscopy (SEM) and X ray diffraction (XRD). Film roughness (r.m.s) and grain shape were found to be correlated with the annealing temperatures. SEM result has shown that its surface characteristics are strongly influenced by annealing temperatures.

Abstract: Two-step sintering (TSS) was applied on the BaCe_0.54Zr_0.36Y_0.1O_2.95 powder and the effect of the second step temperature (T2) during sintering process on the grain growth, density and hardness is reported. Normal sintering with holding temperature of 1500 °C and four different TSS profiles with four various T2 (1150 °C, 1250 °C, 1350 °C, 1450 °C) were conducted. From the results, sample sintered via TSS at T2 of 1450 °C shows the highest density compared to other samples including sample sintered via normal sintering at temperature 1500 °C. The grain size of the sample sintered at T2 of 1450 °C also smaller than the sample sintered via normal sintering. Result from hardness test proves the hardness also increase when the density increase.

Abstract: Active packaging is a promising form of modern food packaging with great potential; economically, environmentally and generally, as it gives a lot of health benefits. Active and smart packaging is made by incorporating suitable colour indicators into food package matrices and applying a bio switch concept to inhibit the spoilage and the pathogenic microorganisms. The main objective of this study are to evaluate starch-based hydroxyethyl cellulose (HEC) the best formulation of methyl red and bromothymol blue that can react with wide pH ranges and the effect of the smart film indicator incorporated with methyl red and bromothymol blue. A solution casting method was used in the film preparation and colour indicators were incorporated before casting. The ratio of 50:50 methyl red and bromothymol blue showed the best formulation which can react with a wide range of pH buffer 1 to 13 compared to ratio 20:80 and 80:20 of methyl red and bromothymol blue. The ratio of 50:50 methyl red and bromothymol blue were then selected to be incorporated into the film to see the effectiveness of the indicator film in order to detect the changes of pH.

Abstract: In this paper a robust approach for detecting QRS complexes and computing related R-R intervals of ECG signals named (RDQR) has been proposed. It reliably recognizes QRS complexes based on the deflection occurred between R & S waves as a large positive and negative amplitude differences in comparison with respect to other ECG signal (P and T) waves. The proposed detection approach applies the new direct algorithm applied on the entire ECG itself without any additional transform like (wavelet, cosine, Walsh transform, etc.). According to the strategy based on positive and negative deflection it overcomes the problem of QRS direction positive (upright) or negative (inverted). Three different types of ECG online database with duration of 10 sec (MIT-BIH Arrhythmia, ST Change Database and Normal Sinus Rhythm) are used to validate the detection performance. The results are demonstrated that the proposed detection approach achieved (100%) accuracy for QRS detection also very high accuracy in evaluating related R-R intervals.

Abstract: Dye-sensitized solar cell (DSSC) of natural dyes from local fruits which consist of the carbonyl and hydroxyl groups of anthocyanin molecule influences the performance of photosensitized effect due to high interaction on the surface of filler. The study is based on Titanium Dioxide, TiO₂; U1and U2 (without and with additive respectively), treated TiO₂ with ultrasonic; U3 and U4 (without and with additive respectively). The additive for electrolyte, KI₃ gives effects on the rate of electron injection to the oxidized dye sensitizer. Of treated TiO₂ with ultrasonic was reduced the particle size agglomeration from 0.37 μm down to 0.15 μm. This contributes to a better sponge like with high porosity in order to absorb more anchorage dye sensitizer. Treated U4 with addition of additive for electrolyte gives, Voc=0.74228 V, Isc=0.36 mA, FF=57.0124 gives 0.039% of efficiency.

Abstract: Fly ash is residue from the combustion of coal which widely available in worldwide and lead to waste management proposal. Moreover, the use of fly ash is more environmental friendly and save cost compared to OPC. Fly ash mostly consists of silicon dioxide (SiO₂), aluminium oxide (Al₂O₃) and iron oxide (Fe₂O₃). The chemical compositions of the sample have been examined according to ASTM C618. Different sources of fly ash may result in different chemical composition. The fly ash is mainly an amorphous material with the presents of crystalline phase of quartz and mullite. Fly ash consists of mostly glassy, hollow and spherical particles.

Abstract: Huge amount of waste electrical and electronic equipments (WEEE) or electronic waste (E-waste) has been produced every year in the world. It consists of valuable and hazardous metals that can be reused or extracted to minimize the environmental impact. This study is focusing on the investigation of recycling potential of e-waste through manual dismantling process and leaching test. The leaching test was conducted by changing the initial pH with constant stirring speed, constant water-sample ratio and in open air. The morphological structures of the solid samples were observed by SEM and the liquid residue was analyzed by Atomic Absorption Spectroscopy (AAS). It was found that total time required to dismantle all parts in the waste motor is about 10 minutes and the part that required longest dismantling time was armature windings. The metal elements that were observed are Fe, Mg, Pb and Cr. It was found that the pH of the solution increased with the increasing leaching time. The dissolution of Fe and Pb was high in the early stage of leaching but gradually decreased afterward. The dissolution for Mg and Cr was low throughout the leaching process. It was revealed that the metal elements in e-waste can be dissolved using this method and further investigation to increase the dissolution rate is required to ensure that the method proposed is applicable in industry. However, dissolved concentration of Pb must be controlled to ensure that it follows the permissible amount set under environmental standard.