Applied Mechanics and Materials Vols. 110-116

Abstract: This paper presents the application of Particle Swarm Optimization (PSO) algorithm for optimization of the Gas Turbine Engine (GTE) fuel control system. In this study, the Wiener model for GTE as a block structure model is firstly developed. This representation is an appropriate model for controller tuning. Subsequently, based on the nonlinear GTE nature, a Fuzzy Logic Controller (FLC) with an initial rule base is designed for the engine fuel system. Then, the initial FLC is tuned by PSO with emphasis on the engine safety and time response. In this study, the optimization process is performed in two stages during which the Data Base (DB) and the Rule Base (RB) of the initial FLC are tuned sequentially. The results obtained from the simulation show the ability of the approach to achieve an acceptable time response and to attain a safe operation by limiting the turbine rotor acceleration.

Abstract: As a result of the successful implementation of the industrialization plan in 1985; Malaysia has changed from an agricultural economy into industrial based economy. The industrial sector represents the highest consuming sector across all other sectors and accounts for about 48% of all total energy demand. This paper is concerned with an energy saving, economic and environmental analysis of industrial boilers in Malaysia when using variable speed drives (VSD). The results obtained when reducing the speed of water pumps by 60% show that 4 GWh, 93.6% of energy, RM 863,375 and 2,160 ton of CO2 could be saved annually. These results represent high energy saving, environmental and economic benefits associated with this energy saving technology. ABBREVIATIONS

Abstract: The experimental investigation on improving the aircraft aerodynamic performance by DBD (Dielectric Barrier Discharges) plasma is described in this paper. The test has been carried out in a low speed wind tunnel with a wept aircraft model. The plasma actuators were set on the upper surface of swept wing combining with airplane body model. The test results presented include the flow field visualization by PIV (Particle Imaging Velocimetry), lift and drag characteristics under the plasma actuators off and on. The results show that the induced flow by DBD plasma may control the separation on the upper surface of the wing evidently, so that the highest stalling angle of the model increases and maximum lift-to-drag ratio rises, respectively. But with the wind velocity increasing, the effect of the plasma decreases gradually.

Abstract: Putting forward the straight-line trajectory of MEFP （multi-explosively formed penetrators, also called attack unit） in the target coordinate by means of building ground coordinate and target coordinate and the conversion of ground coordinate to target coordinate in the Area Blank off Weapon System. According to the intersection criterion that there are only two points between the attack unit straight-line trajectory and the cylindrical surface of the target, whether attack unit hits the target or not is decided. The intersection criterion is applied on the simulation of all kinds of different distributed plans.

Abstract: —This study investigates the upstream of the juncture flows generated by the circular cross section cylindrical body mounted on a flat plate using PIV (Particle Image Velocimetry) technique. The flow structure of laminar horseshoe vortex and a topological insight into the flow pattern of the vortex system were observed. Vortex structures for Re_D (Diameter Reynolds number) 1600, 2000, 2400 and 3500 are predicted and discussed in detail. Experiments were conducted to investigate the structure of steady and periodic horseshoe vortex, the effect of Diameter Reynolds number, location of horseshoe vortex core and its variation with the change in Diameter Reynolds number and the location and nature of the saddle point located most upstream of the leading edge of the cylinder. The results revealed that (a) two different flow regimes were observed corresponding to four Reynolds number ranges; (b) the upstream vortex systems approach closer to the cylinder whereas the distance of saddle point located upstream of the leading edge of the cylinder moves away from the wall when the Reynolds number increases.

Abstract: The Optoelectronic properties of organic-inorganic hybrid devices consisting of Ag/VOPc/n-Si/Ag structure have been investigated through analyzing the current-voltage characteristics. We have also studied the effect of illumination on the open circuit voltage, capacitance and reverse resistance with consideration of VOPc film thickness. The dark I-V characteristics display rectification behaviour of such hybrid structures and a very high photo-capacitive response under illumination of 200 lx is observed. Furthermore due to the generation of photo induced charges, under illumination, the decrease in reverse bias resistance to one third of its value is observed.

Abstract: Relative biological effectiveness (RBE) for the inactivation of V79 cells were determined using the initial slopes of survival curves (published in literature), the physical quality parameters are interpolated utilizing the standard values relevant to charged particles such as protons and heliums. The issues of utilizing physical parameters as quantifier of radiation effects that influence the effectiveness have been investigated. The results show that the effectiveness may represent in terms of other physical parameters rather than linear energy transfer (LET). Meanwhile, mean free path for linear primary ionization (λ) is expressed the generalized specifier physical quality parameter to quantify ionizing radiation effects at lower doses. Therefore, plot of mean free path as a function of RBE has been made to identify the physical features of this parameter as an alternative physical quality for LET.

Abstract: A Volume of Fluid (VOF) method is used to study the breakup of droplets in T-junction geometries. Symmetric T-junctions, which are used to produce equal size droplets and have many applications in pharmacy and chemical industries, are considered. Two important factors namely "breakup time" and "breakup length" that can improve the performance of these systems have been introduced. In addition a novel system which consists of an asymmetric T-junction is proposed to produce unequal size droplets. The effects of the channel width ratio and the capillary number on the size and length of the generated droplets and also the time of the generation have been studied and discussed. For simulation the problem, a VOF method used and for verifying the accuracy of the simulation the results compared with two analytical researches and a good agreement was found. The results indicate for the systems that generate equal size droplets, in a specific Capillary number (in our case 0.02) the performance of the system is in its optimum condition. Also for the systems that generate unequal size droplets, in large capillary numbers a wider range of droplets with different sizes can be produced.

Abstract: Interconnect dimensions and CMOS transistor feature size approach their physical limits, therefore scaling will no longer play an important role in performance improvement. So, instead of trying to improve the performance of traditional CMOS circuits, integration of multiple technologies and different components in a heterogeneous system that is high performance will be introduced “moore than more” and CMOS replacement”beyond CMOS” will be explored. This paper focuses on Technology level trends where it presents “More Moore”:New Architectures (SOI, FinFET, Twin-Well),”More Moore” :New Materials (High-K, Metal Gate, Strained-Si) ,”More than Moore”:New Interconnects Schemes (3D, NoC, Optical, Wireless), and ”Beyond CMOS” :New Devices (Molecular Computer, Biological computer, Quantum Computer) .

Abstract: The influence of the nucleation process of Ag particles on the formation of Si nanowire arrays is investigated by two-stage electroless chemical etching. The dimensions of the Ag particles formed in the first stage of the process play an important role in the formation of the Si nanowires. The nucleation and etch result are analysed using SEM. The electrical properties of the resulting Si NW arrays are also studied.