Advanced Materials Research Vol. 856

Abstract: Carbon nanotubes grafted with stearyl alcohol (CNTs-SA) was used to enhance the thermal conductivities of the microcapsules. Differential Scanning Calorimeter (DSC) and thermogravimetry (TG) analysis method are employed to measure thermal properties of the prepared MicroPCM containing the grafted CNTs (MicroPCM/CNTs-SA). The results indicated the phase change temperature and latent heat of MicroPCM/CNTs-SA was 26.2°C and 47.7J/g. An increase in thermal conductivity, thermal stability of MicroPCM/CNTs-SA was observed. After 100 heating and cooling cycles, MicroPCM/CNTs-SA still had better durability and thermal stability.

Abstract: Dilute acetic acid was used to pretreat sugarcane bagasse with 180°C steam explosion prior to anaerobic digestion. The Central Composite Design (CCD) was employed to recognize the optimum condition of pre-treatment sugarcane bagasse for biogas production. The individual variable effects of acetic acid concentration and reaction time on enhancing biogas production were investigated using response surface methodology (RSM). Data obtained from RSM analysis on biogas production were depending on analysis of variance (ANOVA). After optimization, the optimum pre-treatment condition was at 1.0% acetic, 17.45 min reaction time, while the maximum biogas production (434.47 L/kgVS) was 91.88% higher than the control (226.42 L/kgVS). Hence the optimum pre-treatment conditions for maximum biogas production were obtained by RSM analysis. It can be concluded that dilute acetic acid and steam explosion techniques can be used to achieve higher biogas.

Abstract: The objective of this research was to evaluate the quantity of biogas production from napier grass (Pak Chong 1) (Pennisetum purpureum × Pennisetum americanum) in three identical continuously stirred tank reactor (CSTRs) at room temperature. The volatile solids feed was varied at 1.5, 2 and 3%, respectively. The organic loading rate was altered at 0.43, 0.57 and 0.86 kg VS/m³.d in CSTR 1, 2 and 3, respectively. Three laboratory scale CSTRs with working volume of 5 l were carried out. The results showed that the optimum volatile solids fraction was 2% VS with maximum biogas production of 0.529 m³/kg VS added. The methane production was achieved at 0.242 m³/kg VS added. Under this condition, the soluble chemical oxygen demand (SCOD) of the hydrolysate was increased by 74% and the SCOD and VS removal efficiency were obtained 52.52% and 55.98%, respectively. The highest total volatile fatty acid was obtained on day 12, which was 5.51 g/l and the highest concentration of HAc was 4.33 g/l. The results indicated that volatile solids fraction was 2% VS achieves a maximum biogas yield and can be successfully converted using anaerobic digestion and was investigated into economical and scalable.

Abstract: Without any doubt, one of the most worldwide challenging and controversial issues in the current century is the energy problem. In most countries, the increase of energy consumption, especially in building, has made energy saving and efficiency strategies important target for energy policies. In general, there are many ways to save energy. The most common method of economizing is within culturalization. For such purpose, building energy management system (BEMS) is considered as the latest idea of energy. Having a dynamic environment, smart buildings are affordable by the integration of four main elements: systems, structure, service, management, and the relationship between them. Intelligent buildings provide these benefits through intelligent control systems. In this paper, while introducing the energy management in buildings, it studies their applications and also their effects on management and optimization of energy consumption. The office building in San Francisco, USA with 66,943 ft² area is considered as a case study for this research. Energy consumption is reduced 50 percent by implementing BMS in this building.

Abstract: Burning fossil fuel like coal in power plants released carbon dioxide that had been absorbed millions of years ago. Unfortunately, excessive carbon dioxide emission had led to global warming. Malaysia, as one of the major exporters of palm oil, has abundant oil palm mill residues that could be converted into value-added product like biomass fuel briquettes. Fuel briquette with palm kernel shell and palm mesocarp fibre as its main ingredients showed satisfactory fuel characteristics and mechanical properties as a pure biomass fuel briquette. The effects of adding some coal of higher calorific value to the satisfactory biomass fuel briquette were focused in this study. Various coal-biomass fuel blends were used, ranging from 0wt% coal to 50wt% coal. The fuel properties and mechanical properties of pure biomass briquette and briquettes with different amount of coal added were compared experimentally. From the fuel properties tests, it was found that as the coal content in the briquette was increased, the carbon content and calorific value increased. Mechanical property tests on the fuel briquettes showed a mixture of results, with some favored higher portion of coal in the briquette for better handling, transport and storage properties while some favored greater amount of biomass.

Abstract: Burning biomass in power plants is believed to result in severe fireside corrosion of superheater/reheater tubing and cause unexpected early failures of tubes. Morover, higher operating temeprtures and pressures (to increase the boiler efficiency) will also increase the risk of fireside and steamside oxidation damage to the boiler tubing and lead to shorter component lives. Predicting the remaining service life of superheater/reheater tubes in coal-biomass fired power plants is therefore an important aspect of managing such power plants. The path to this type of failure of tubes involves five processes: combustion, deposition, fireside corrosion, steam-side oxidation, and creep. To fully understand the impact of new fuel mixes and changing operating conditions on such failures, an integrated model of all of these processes is required. This work has produced an integrated set of models and so predicted the remaining life of tubes based on the conceptual and mathematical frameworks developed.

Abstract: Through experiment, the variation of the exhaust energy of the vehicle diesel engine is studied, a set of vehicle diesel engine-organic Rankine cycle (ORC) combined system with internal heat exchanger (IHE) is designed, the zeotropic mixtures R416A is used as the working fluids for the ORC system with IHE, by theoretical analysis and numerical calculation, the variation of the vehicle diesel engine-ORC combined system with IHE under entire operating conditions of the diesel engine is studied, the calculation results show that, when engine is operating at high speed and high torque, the performance of the vehicle diesel engine-ORC combined system with IHE is higher.

Abstract: This paper describes a current mode filter using two current feedback amplifiers (CFA's). One CFA is used to simulate a negative resistor. The proposed circuit is very useful for low as well as high frequency applications. Circuit is simple and canonic. The use of grounded capacitors in the design make it suitable for implementation in CMOS technology.

Abstract: An appropriate configuration of the magnetic bias geometry used in waveguide based phase control sections can help to reduce size, bulk and energy utilization. In this paper ferrite inserts for a toroidal phase controller are fabricated using a viscous plastic processing method. This technique has been exploited to produce a low reluctance magnetic geometry that avoids machining. The magnetostatic result for the bias geometry has been computed and used to analyze the phase control characteristics of a twin toroid phase controller. The microwave response in terms of S-Parameter over 8-12 GHz for various magnetization levels has been measured. The insertion loss of less than 1.1 dB has been achieved. The reflection coefficient (<22 dB) has been experimentally verified.

Abstract: Road safety is of high importance in our modern life in terms of social and economic. The helmet is the head protective system the most common used. Their main function is to reduce or prevent damage that may occur during an impact due to an accident. The head will be better protected if the more important quantity of the energy caused by the kinetic energy of the impact is absorbed by the helmet. The greater part of the impact energy should be absorbed by the deformations of the different layers of the helmet. The analytic equations of the model of the helmet parts show a realistic dynamic reaction of the different layers after the shock impact. These results will permit a better comprehension of the helmet behaviour to violent impact and the energy distribution in the different layers so a better optimisation of the head helmet in the future.