Browsing by Author "Herath, H.M.C.M."
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Item Design of an Automated Damage Inspection System for Aircraft Wheel Hubs(Uva Wellassa University of Sri Lanka, 2021) Gamage, W.G.K.P.; Dharmathilaka, I.P.; Karunarathne, W.A.K.; Nishshanka, N.A.I.P.; Herath, H.M.C.M.; Lakmal, S.D.R.The wheel assembly is one of the most critical parts of an aircraft. Landing, take off and taxi operations generate repetitive stresses on the wheel hubs, resulting in small imperfections or damage that can potentially grow into cracks. These cracks may cause catastrophic failures that harm the passengers’ lives. At present, the Sri Lankan aviation industry uses handheld eddy current inspection equipment for aircraft wheel hub inspection. The handheld inspection method reduces the accuracy of the testing. This study proposes a design of a pre-coordinated eddy current inspection mechanism using Arduino programming. Component Maintenances Manual (CMM) provides by the aircraft manufacture describes the standard inspection methodology of the wheel hub. According to the CMM, the beading area of a wheel hub should be thoroughly inspected as the beading area has repetitive stress concentration. The inspection is done by the rotating wheel hub on a rotary table, and placing a scanning probe on the surface at the top of the bleeding area gradually moves down the probe in 2 mm steps. When the machine operates, there is relative motion between the wheel hub and the moving arm. In order to reduce the moment of inertia, the tray rotates at 50 RPM. On the assembling step, a collision check was done on mates. The time for each wheel hubs with change concerning the size of the wheel hub. If someone chooses the wrong size, the probe might be damaged so, safety switches have been installed on the moving arm as a safety feature. The proposed design was aimed to inspect four types of wheel hubs (wheel sizes: A330 (main and nose wheel), A320 (main and nose wheel). These sizes have been coded on the Arduino code. The proposed design will facilitate high accuracy, time-efficient, and low-budget NDT inspection operation. Keywords: Non-destructive testing; Eddy current; Crack damage; automated inspection system, Aircraft maintenanceItem Smart Sun Tracking System for Solar Energy Generation(Uva Wellassa University of Sri Lanka, 2021) Madhushani, Y.P.L.; Chandrasiri, K.H.M.C.; Jayawickrama, J.K.A.S.M.; Lakmal, S.D.R.; Herath, H.M.C.M.The use of renewable energy is becoming more prevalent with the global energy crisis. Solar energy is nature's most abundant renewable energy available around the world. The main challenge with solar energy harvesting is the reduction of solar energy absorbed by the use of photovoltaic (PV) systems. Excellent performance of PV systems can be achieved when the panel is oriented perpendicular to the radiation direction of the sun. Solar tracker systems are capable of optimum positioning of the PV panels to capture maximum solar radiation. Single axis solar trackers are widely used around the globe at the present day. The single axis tracking systems produce lower energy output during sunny times and it can track the daily change of Sun’s position but not seasonally. This study proposes an automated dual axis solar tracking system considering the limitations of fixed panels and single axis trackers. This project involves the designing and developing of an automated dual axis solar tracking system for domestic energy purposes. Moreover, demonstrates a prototype of the proposed dual-axis solar tracking system. The proposed dual-axis solar tracker increased energy generation by tracking Sun rays from switching solar panels. Sun rays are detected in different directions by the LDR system with a smart solar sensor mechanism. Advanced LDR arrangement and Algorithm development enabled way to smart sun tracking. The development of an Algorithm for this sensing mechanism improves the effectiveness and accuracy of the system. It is more accurate than a fixed solar panel and single axis system. Moreover, this design can be applied to the large-scale solar energy system in practice. This project is also expected to investigate the performances of the dual axis tracking system compared to the system with a fixed mounting method. Keywords: Solar energy; Photovoltaic; Sun tracking system; Automation; Micro-controllerItem Statistical Modeling of Reselling Price of Suzuki Model Used Car in Colombo District(Uva Wellassa University of Sri Lanka, 2020) Herath, H.M.C.M.; Arumairajan, S.Car reselling is a timely, very popular heading in Sri Lanka and a large number of cars are resold daily. A lot of people are in the practice of reselling their car every time based on different reasons. Many different factors affect the reselling price of used cars. This study aimed to identify the factors that influence the reselling price of used Suzuki cars in Colombo, Sri Lanka, and to find the best multiple linear regression model. For this study, the 90 reselling prices of Suzuki used cars in Colombo district were collected from January 2019 to March 2019. In this study, Mileage of the car in km, Age of the car in years, Model of the car (Swift, Alto, Wagon-R, A-star, and Spacia), Color of the car (Light, Dark) and Number of past owners of the car were considered as independent variables. In this research, a multiple linear regression model has been used to identify the factors that affect the reselling price of the car. Furthermore, the forward selection, backward elimination, and stepwise regression methods have been used to find the best multiple linear regression model. According to the final results of this study, the principal factors that affect the reselling price of used Suzuki cars in Colombo district were mileage of the car, age of the car, the model of the car, and the number of past owners of the car. Finally, the model obtained in this study will be useful for both buyers and sellers. Keywords: Reselling price, Colombo, Used car, Suzuki car, Multiple linear regression