Abstract: This paper describes the investigation of the effect on the Wireless Local Area Network (WLAN) signals due to fixed and non-fixed variables in the indoor environment. The measurement system consisted of a spectrum analyzer and a log-periodic antenna. Line-of-sight (LOS) propagation and non-line-of-sight (NLOS) propagation (in furnished rooms) were discussed. All the measurement sites mentioned in this paper are located in the Division of Information Technology at Universiti Putra Malaysia. The furnished rooms included a teaching laboratory, a computer laboratory, and an operating office plus a server room. The effects of the various types of materials at the measurement sites also are described here.

Abstract: In the past decades, many impressive progress had been made in the field of simulation and analysis, even though experiments are necessary in many fields to conduct investigation on mechanical components [26]. Gears are one of the such components that needed to be tested experimentally. Therefore, test rigs are required with the possibility of varying speed and torque during the test, based on the requirement. In this paper, development of test rigs for evaluating the performance of gear has been studied. The main objective of this paper is to give researchers an idea about the physical development of a gear test rig. Test rig developed by various researchers based on the parameters to be tested were discussed with schematic representation and test procedure. A new gear test rig also fabricated by the authors and development procedure of the same was discussed.

Abstract: Sleep apnea disorder or sometimes called as Obstructive Sleep Apnea (OSA) usually last for at least 10 seconds and it often goes undiagnosed as it is poorly recognized by the majority of the population. The level of blood-oxygenation could be decreased during the event to the patient and this could lead to other health risk. Current practice in diagnosing this event is using Polysomnography (PSG) in sleep test. This typical PSG is used to record the biophysiological changes that occur during sleep. However, this technique have some limitations since the patient feels uncomfortable to sleep with various electrodes and wires are attached to the body and also need a dedicated room for conducting the sleep test. The blood oxygen and snoring sound are suggested to improve the current technique and assist physician to monitor and diagnose the OSA problem. Therefore, a measurement system for monitoring the blood oxygen and snoring sound and frequency is developed. Preliminary results of the developed system demonstrated the system is proven reliable, practical and provide comfortable to be used in the sleep test study.

Abstract: Microstrip patch antenna is a flat shape, light weight and low cost antenna that used to receive and transmit electromagnetic wave. This paper describes the design and development of a microstrip patch antenna for salinity and sugar detection. The microstrip antenna was designed and fabricated using Computer Simulation Technology (CST) Microwave Studio and Taconic TLY-5 substrate, respectively. This sensor is operate in the Industrial, Scientific and Medical (ISM) radio band, i.e. 2.45GHz. Dimension and shape of the patch antenna as well as location of feed point is analyzed. There are three types of microstrip patch antennas are developed in this work, i.e. rectangular, circular and square patch microstrip antennas. These microstrip patch antennas were used to measure the salt and sugar content in water. In addition, reflection coefficient and Q-factor were discussed too in this paper. Different amount of salt or sugar that present in water will exhibit different dielectric properties, and in turn change its reflection coefficient and Q-factor.

Abstract: The present work is aimed to optimize the parameters of wire electric discharge machining (WEDM) process by considering the effect of input parameters viz. Time On, Time Off, Wire Speed & Wire Feed. Experiments have been conducted with these parameters in three different levels data related to process responses viz. Metal removal rate, surface roughness (Ra) have been measured for each of the experimental run. These data have been utilized to fit a quadratic mathematical model (RSM) for each of the responses, which can be represented as a function of the process parameters. Predicted data have been utilized for identification of the parametric influence in the form of graphical representation for showing influence of the parameters on selected responses. Predicted data given by the models (as per Taguchi’s L9 OA) design have been used in search of an optimal parametric combination to achieve desired yield of the process. Taguchi techniques has been used for optimization. The optimal value has been verified to the predicted value.

Abstract: The size and distribution of in-cylinder soot particles affect the sizes of soot particles emitted from exhaust tailpipes as well as the soot in oil. The simulation work reported in this paper focuses on the study of soot formation and movement inside a diesel engine with in-depth analysis of soot particles in the squish region. Soot particles in the squish region have high potential to be deposited onto the cylinder wall, and subsequently penetrate into engine lubrication system and contaminate the oil. The prediction of a soot particle pathline and size distribution was performed using post-processed in-cylinder combustion data from Kiva-3v computational fluid dynamics (CFD) simulations with a series of Matlab routines. Only soot oxidation and soot surface growth process were considered in this study. Coagulation and agglomeration of soot particles were not taken into account. Soot particles were tracked from 8 crank angle (CA) degree after top dead center (ATDC) as soot starts to form in high concentration until 120 CA degree ATDC at exhaust valve opening (EVO). The soot particle size and its distribution were analyzed at different crank angles. In the squish region, the most dominant soot particle size was 20-50 nm at earlier crank angle and in 10-20 nm range at 120 CA ATDC. The percentage of soot loss in the squish region was analyzed to be 23.2 % and the soot loss was higher at earlier crank angle until 10 CA degree ATDC due to high rate of oxidation.

Abstract: This work is proposed to develop a low cost measurement system to check the salinity and sugar content of food. A Mini-Circuits ZX95-2800+ voltage controlled oscillator (VCO), Mini-Circuits ZGDC10-362HP+ high power directional coupler, Mini Circuits PWR-6GHS+ USB Smart power sensor and open-ended coaxial probe made of semi-rigid coaxial cable RG402/U are used. The main idea for this work is based on electromagnetic reflection due to the impedance mismatch. In order to verify efficiency and accuracy of this developed detection system, comparison with measured result from P-series network analyzer (PNA) is conducted. The measured reflection coefficient from developed system was discussed among Agilent 85052D High-Temperature probe, RG405/U and RG402/U open-ended coaxial probe.

Abstract: Selection of appropriate unique keyless grill locking system concept which complies with customer and technical requirements is one of the complicated decision making problem. In order to solve this problem, an idea selection based on the application of Analytic Hierarchy Process (AHP) is developed. This technique breaks down the multi-criteria into several levels and computes them using pairwise comparison matrices. The concepts of unique keyless grill locking system were evaluated using four main criteria: cost, quality, performance, and manufacturability. The results of the study indicate that the optimum concept is selected based on the highest score achieved from the overall ranking of each alternative concept.

Abstract: Modern vertical axis wind turbine is a promising technology, appropriate for small scale applications in urban areas and isolates sites for different uses. Including pumping water, producing electrical power, passive starting others turbines and purposes. The Savonius wind turbine is a robust and reliable mechanical device, easy to build, produces less noise. The formation and growths of cracks in this system reduces its stiffness and yield strength, which lead to a poor performance and system failure. The system works under the wind flow dynamic loading. Then, it is subject to mechanical and aerodynamical cyclic stresses to be inducing the fatigue and shortening the system lifetime. The diagnosis of the system by using nondestructive techniques based on magnetic particle, dye penetrant and ultrasonic are costly. The use of natural frequencies shift measured between uncracked and cracked structure is very small regardless the varying of crack depth and location, undetectable in the practice. The application of analysis and simulation tools based on (CAD) permits to evaluate the system design early in the design process. This technique allowed determining the causes of premature failures, quickly explored designs changes in the aim to reduce cost as well as weight, and estimated the safety factor of product. Present paper investigated the influence of weight and centrifuge force on the static design of a three-bladed Savonius wind turbine cracked under various wind speeds from 5 to 15 m/s. The transverse crack is formed and growth normally to the low speed shaft and to end side of blades. From simulation results, the reliability of wind turbine is strongly influenced by the increasing of wind speed since the security factor was decreased from 14.6 to 1.39. However, the influence of crack on mechanical proprieties of the system, stress, strain and displacement is very small, for all study cases, depth variation from 0 to 50% of the shaft diameter and at different settings. The effect is undetectable in the practice for in online monitoring of the wind turbine.

Abstract: The project deals with the experimental study of Single Expansion Ramp Nozzle (SERN) flows at low supersonic speeds. The preliminary design is carried out for three different ramp angles of 18°, 20° & 22° and the model is fabricated. The study includes the effect of cowl length such as 0h, 1h, 2h,3h &4h (Where h is the height of the nozzle throat) on the performance of SERN. The experiment has carried out at lowNozzle Pressure Ratios (NPRs)ranging from 2 to 6.The readings for total pressure is taken along the axis of the nozzle. The Pitot tube fitted with three dimensional traverse mechanisms is used to take the total pressure reading at different X/h locations of the nozzle. A pressure scanner and pressure indicator connected to Pitot tube is used to measure the total pressure.

Abstract: Due to the rapid growing market competitiveness, more reliable and robust condition monitoring systems are critically needed in a wide array of industries to improve production quality and reduce cost. As a result, in recent years more efforts have been taken to develop intelligent techniques for online condition monitoring in machinery systems. Although several neural fuzzy classification schemes have been proposed in literature for fault detection, their reasoning architecture remains fixed, allowing only the system parameters to be updated in pattern classification operations. To improve the reliability of machinery fault diagnostics, a self-evolving fuzzy classifier is developed in this work for gear system condition monitoring. The evolution is performed based on the comparison of the potential of the incoming data set and the existing cluster centers. The developed evolving fuzzy classifier has the ability of adding or subtracting rules adaptively. A scaled Kalman filter method is suggested to improve training efficiency. The effectiveness of the developed classifier is evaluated experimentally. Test results show that the proposed classifier can effectively identify the condition of gears, and it outperforms other related methods.

Abstract: The stem design, geometry and material change the mechanical behavior of bone around tibia tray and stem after TKA. In this study a shape optimization of a cemented tibia stem has been carried out to solve the stress shielding at the proximal tibia as well as the stress concentration at the stem tip. It is found that the optimal shape is a short stem with small diameter at the distal stem tip increased gradually to reach a maximum value at the proximal tibia stem. This optimal shape is increased von Mises stress at the lateral and medial cancellous bone by 130% and 140%, respectively compared to initial stem shape. On the other hand the stress concentration in bone at stem tip using the optimal stem shape is reduced by 25% compared to initial shape. However, the optimal stem shape is reduced the stresses in cement at stem tip by 28% laterally and 17% medially compared to the initial stem shape. Finally, a bimaterial stem (titanium with a polymer stem tip) has been applied to the optimal shape to improve the stress concentration reduction at the stem tip. The results are approximately the same compared to the optimal titanium stem shape.

Abstract: Research is essential to be carried out to find the suitable alternative fuel to meet the energy demand with minimum environmental effect, because of fast depletion of fossil fuels. In future, the alternative energy systems be cost effective, environmental free, reliable, renewable, convenient and safe. In this review, positive features and limitations of using hydrogen as Spark ignition engine fuel is discussed in detail. Hydrogen is superior in many aspects over conventional fuels and produce satisfactory performance in engine applications. To meet the current restrictive emission norms, hydrogen will be one of the most important fuel in the near future. In this analysis, hydrogen engine fundamentals are described by examining the engine specific properties of hydrogen and the existing literature are surveyed.