PWM Inverter for Electric Drive Train Application

Controlling AC power load using DC supply requires complex design and circuit. Basically the controlling system comprises of low power control unit, inverter and the load. Multiple Pulse Width Modulation (MPWM) technique was used for controlling the control unit design as it gives low harmonic distortion compared with other types. Six MPWM signals were used to trigger the six channels in inverter circuit and all the signals were synchronous to avoid short circuit in inverter circuit. The design of the MPWM was simplified with an IC IR2130, which provided matched voltage trigger, adequate dead time for low and high channels and over current shut down. In inverter circuit design the main component in controlling the high current flow from DC supply to load is power device. There are various power devices available in the market but IGBT was chosen due to its high current rating and simple triggering process. Apart from single IGBT with high current rating being used in each channel; paralleling several IGBTs is also the technique that can be used to increase the power conversion in inverter circuits and to reduce the cost of design. It is evident that by paralleling several low current power devices, the amount of current produced equates the single high current power device. For the AC load, three-phase squirrel cage AC motor was chosen after comparing with other types of motors as it provides several advantages in terms of being robust, cheap and maintenance free. Overall result showed there was smooth control of AC motor using single configuration technique compared to using parallel configuration technique. Further investigations are required especially on the use of parallel configuration technique with IGBT as power device and also in simplifying the complex snubber circuit, needed for protecting power devices in inverter circuit from high current and voltage transients

Effects of Fuel Additive on Performance and Emissions Characteristics of Diesel Engine Fuelled by Biodiesel Derived from Palm Oil

Abstract. Biodiesel is the alternate fuel which is derived from renewable sources either is vegetable oils or animal fats. Biodiesel is non-toxic, have higher biodegradability, free of sulphur, no aromatics and its oxygen content of about 10-11% which is usually not contained in diesel fuel. These characteristics thus predominantly influences to the emissions of carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas. Purpose of this study is to investigate the effects of fuel additive, oil palm blended fuel, engine speed and test load conditions on the exhaust emissions and engine performance. The engine speed was varied from 1500 to 3000 rpm, load test condition varied by dynapack chassis dynamometer in 0, 50 and 100% and blends of 5(B5), 10(B10) and 15vol%(B15) palm oil with the diesel fuel. Increased of blends ratio with same mixing booster quantity can improve the engine performance, combustion process and give less CO emission. However, this condition tends to produce high NOx production due to higher oxygenated fuel in biodiesel content. Introduction Biodiesel which can offer the aspects as above is getting the higher attention from human being and the properties, performance and emissions of biodiesel have been further investigated. However, most biodiesel fuels have faced the problem where the fuels are not operating efficiently due to the variant in fuel properties. In diesel engine, the relation between mixture formation during the ignition delay period and burning process in diesel combustion that strongly affects the exhaust emission

University students involvement in cyber-bullying : a case study among UiTM students in Kota Bharu, Kelantan / Nurul Ainna Abas, Balqis Farhana Shahrom and Faizatul Nabila Khairol Amir Rashid

This research paper intended to examine the most significant factor contributing to students’ involvement in cyber-bullying and indirectly raise students’ awareness regarding the issue of cyber-bullying. Besides that, this study determine to study about the relationship of technological, psychological and sociological factors with UiTM Kota Bharu’s students’ involvement in cyberbullying. 116 students of UiTM Kota Bharu were selected to participate in this study through simple random sampling technique. A google form link was sent to each respondent through a messenger application called “Whatsapp” application, and also through e-mail. The information obtained was then analyzed using Multiple Linear Regression analysis. The results in this study found that only psychological factor had a significant contribution towards students’ involvement in cyber-bullying, whereas the other two factors did not have any significant effect. It was also found that the mean of cyber-bullying involvement for male students was not equal to the mean of cyber-bullying involvement for female students. Male students were found to have a greater mean of cyber-bullying involvement compared to female student

Finite Element Analysis of Thermoelectric Generator with Aluminum Plate for Waste Heat Recovery Application

Thermoelectric generator (TEG) is the solid state device that converts the thermal gradient into electrical energy. TEG is widely used as the renewable energy source especially for the electronic equipment that operates with the small amount of electrical power. In the present analysis, the finite element analysis (FEA) using ANSYS is conducted on a model of the TEG attached with the aluminium, Al plate on the hot side of the TEG. This simple construction of TEG model was built in order to be used in the waste heat recovery application. It was shown that the changes of the width and thickness of the Al plate increased the temperature gradient between hot and cold sides of TEG. This directly increase the voltage produced by the TEG based on the Seeback effect. The increase of the thermal gradient due to the increment of thickness and width of Al plate might be because of the increase of thermal resistance of Al plate. Based on statistical analysis using full factorial of design of experiment, Al thickness play a major role in changing the performance of proposed TEG compared to that of Al width. This finding provides a valuable data in design process to build a good TEG attached with Al plate for the waste heat recovery application

Comparison of hash function algorithms against attacks: a review

Hash functions are considered key components of nearly all cryptographic protocols, as well as of many security applications such as message authentication codes, data integrity, password storage, and random number generation. Many hash function algorithms have been proposed in order to ensure authentication and integrity of the data, including MD5, SHA-1, SHA-2, SHA-3 and RIPEMD. This paper involves an overview of these standard algorithms, and also provides a focus on their limitations against common attacks. These study shows that these standard hash function algorithms suffer collision attacks and time inefficiency. Other types of hash functions are also highlighted in comparison with the standard hash function algorithm in performing the resistance against common attacks. It shows that these algorithms are still weak to resist against collision attacks

Performance comparison of SCTP and UDP over mobile ad hoc networks

Countless researchers have put efforts to conduct researchs about the performance of the traditional transport control protocols (TCP) and user datagram protocol (UDP).Recently new transport protocol had been designed calledStream Control Transmission Protocol (SCTP).In this research, we will focus to study the effect of Mobile Ad Hoc Networks (MANET) on these two transport protocols SCTP and UDP and find out which one performs better over MANET.The transport protocol SCTP has more services and features compare to the traditional transport protocol.We also present some literatures on SCTP and UDP performance over MANET.The simulation parameters and the results of the simulation will also be discussed

Renovation and Reuse of Waste Electrical and Electronic Equipment in the Direction of Eco-Design

Nowadays there is a higher need of strict and broader legislation in waste electrical and electronic equipment (WEEE) recycling industry to reduce environmental effects of WEEE. Environmental challenges include pollution, exhaustion of natural resources, waste management and reduction of landfills. High speed in technological development in many sectors puts many products in great challenge of obsoleting almost immediately after their purchase. In particular, this is the fate for electrical and electronic equipment (EEE). They are forever-improving and incorporate state of the art innovations. This provide many benefits; however, at the same time, its expansion results in rapidly growing waste stream of WEEE. WEEE contains a combination of all these situations, including for example, batteries, plastics of quality, precious metals and toxic soldering metals. The reuse and renovation of WEEE are therefore very critical because of its significant ecological environmental impacts. Sustainable development is not a static situation, but a state of dynamic balance between human and environmental system. The current chapter explores sustainability planning and strategies such as eco-design, and design for dismantling and recycling, and what they mean for electronic products. It examines the incentives, methods and tools for sustainable electronic product design, with particular emphasis on reuse, recycling, selection of sustainable materials and processes, and lack of resources

Polypyrrole thin film sensor base surface plasmon resonance for detection of Cu(II) and Fe(III) in aqueous solution

In this study, the performance of surface plasmon resonance method incorporated with polypyrrole sensing layer was examined for detection of Cu (II) and Fe (III) ions in aqueous solutions. The polypyrrole was prepared by electro-oxidation method on a gold layer for the detecting low concentration ions (0.1, 1 5 10 20 ppm). The experiments carried out at room temperature, and each sample was flowed through the flow cell. A photodiode registered the SPR signals as the function of rotation angle and thickness of layers. For observing the association and dissociation processes, the experiments repeated more than ten times, and the sensorgrams were obtained. Furthermore, Langmuir model was utilized to describe the binding interactions of ions with the polypyrrole layer. The lower concentration detection limit was about 0.1 ppm and the terminal resonance angles were occurred after the 300 s. The sensor was also found to be more sensitive to the presence of Cu than Fe ions

The effect of 48V mild hybrid technology on fuel consumption of a passenger car by using simulation cycle

The ASEAN's legislation has become more regulatory towards electric vehicles for automotive manufacturers to ensure the environment is preserved better for future generations. The ASEAN roadmap 2025 requirement in optimizing a conventional vehicle's fuel consumption is implemented with hybrid technology in targeting the automotive industry worldwide to achieve energy-efficient vehicles. This research aims to develop a vehicle model via 1D simulation cycle and implement the 48V mild hybrid to lower vehicle fuel consumption considering perspective in drive cycles data. The vehicle model used in this research is a D-segment vehicle powered by a 1.8L TGDI engine. The base model will be created using a GT Suite software where data is compared and analyzed with actual vehicle measurement. There will be two models produced; with and without Belt-Alternator-Starter (BAS) system. They will be further investigated for their functions based on NEDC and RDC drive cycles for fuel consumption. However, implementing the add-on technology from this simulation improved overall vehicle fuel consumption by 7.7% in NEDC and 1.7% in RDC. The results obtained for the optimization of the vehicle have shown difference by the results of each engine characteristics such as engine fuel flow rate, speed, torque, the BAS functions, and state of charge. The research proposes its findings to understand the practical usage of 48V mild hybrid system in fuel reduction and provide reliable proof to use as a reference for initiative studies

Application of conducting polymer layer for measurement of Ag nanoparticle concentration using surface plasmon resonance

An application of polypyrrole and polypyrrole–chitosan were presented to measure the concentration of silver ion and silver nanoparticles using surface plasmon resonance sensor. These results were compared to those for atomic absorption spectroscopy method. The sensing layers were prepared using an electrodeposition on gold layer with the sensor limitation at about 1mg/L, and well correlated to prior atomic absorption spectroscopy results. The sensor with a polypyrrole-chitosan layer was more sensitive and accurate than the sensor with just a polypyrrole layer