Physics
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Item Smart Automation System for Controlling Various Appliances using a Mobile Device(IEEE Xplore Digital Library, 2019) Gunarathne, S.B.M.S.S.; Kalingamudali, S.R.D.This paper outlines the methodology of designing and developing a smart control system for controlling light, air conditioning and ceiling fans in a room. This system considers the requirements of the users appropriately and makes a comfort zone for the users. An android application with a user friendly Graphical Interface, which is easy to communicate with the smart control system, has been developed. The application is connected with the control system through Wi-Fi across a cloud network and it can respond quickly. RGB LED panel light system that controls the color, color temperature and luminance was designed by considering the requirements of the instances and lighting conditions. Although there are RGB LED panel lights available, there are no systems defined for the activity based color modes. An IR Remote module controller system was built for controlling inverter type air conditioners by giving commands from a smart phone application. This system considers the mean value of the preferences of many users to control the air conditioning system. The running mode of the air conditioner is chosen from the data given through the application by many users in a same place. Although the inverter type air conditioners continuously regulate the temperatures, the fan does not do it. Because of this problem, a ceiling fan controlling system with two modes, automatic and manual, was designed. Automatic mode utilizes the users skin moisture related hybrid system to set the room temperature. Manual mode works according to the suggestions given by the crowd just as the air conditioning system. This air conditioning and ceiling fan control system that works according to the suggestions of crowd is better than the individual preference system using a conventional remote controller.Item Improving the Energy Storage of Standalone PV Systems while Enhancing the Charging Efficiency using Supercapacitors(IEEE Xplore Digital Library, 2019) Piyumal, P.L.A.K.; Ranaweera, A.L.A.K.; Kalingamudali, S.R.D.; Kularatna, N.Usually a battery is used as the energy storage device in typical standalone solar photovoltaic (PV) systems. It is charged by a solar charge controller. The charging efficiency of the system depends on the efficiency of the DC-DC converter of solar charge controller. However, a considerable amount of usable energy is wasted during the charging process. In this work, a method is proposed to utilize this wasted energy and thereby to enhance the charging efficiency. In the case of an empty capacitor being charged by an external source, it stores only half of the energy delivered by the source as compared to that of an electrochemical battery. Therefore, it wastes 50% of useful energy. A portion of this wasted energy can be collected and utilized if a useful resistive load is connected in series to this capacitor charging loop. In this study, a DC-DC converter and battery bank is connected as the useful resistive load in the capacitor charging loop. A supercapacitor (SC) bank is used replacing the conventional capacitor. Therefore, total energy loss in capacitor charging loop can be minimized by storing energy in both battery bank and SC bank. This concept is introduced into a typical PV system for reducing its energy losses. Experimental results show an enhancement in charging efficiency when this new method is employed. The energy stored in the SC bank could be used for driving loads with required electronics.Item Novel Approach for Harnessing Maximum Energy from PV Systems using Supercapacitors(IEEE Xplore, 2018) Piyumal, P.L.A.K.; Ranaweera, A.L.A.K.; Kalingamudali, S.R.D.; Kularatna, N.Typical standalone solar photovoltaic (PV) systems use battery bank as the energy storage device. The battery bank is charged by using a solar charge controller connected to a solar array. For similar PV systems, charging efficiency mostly depends on the efficiency of DC-DC converter available inside the charge controller. However, considerable amount of usable energy will be wasted during the charging process. In this work, a method is proposed to utilize this wasted energy while enhancing the end to end efficiency of standalone PV systems. When an empty capacitor is charged by an external source, it stores only a half of the energy delivered by the source as compared to the case of an electrochemical battery. As a result, 50% of useful energy is lost in the charging loop of a capacitor. If a useful resistive load is connected to this loop, some amount of energy can be utilized by doing a beneficial work. In this study, a DC-DC converter and battery bank has been chosen as the useful load in the capacitor charging loop, and a supercapacitor (SC) bank is used replacing the conventional capacitor. Therefore, total energy loss can be minimized by storing energy in both battery and SC bank. The energy stored in the SCs could be used for driving loads with required electronics. Consequently, it leads to an improvement of end to end efficiency of the PV system.Item Designing and constructing a DC microgrid with uninterrupted power supply capability and optimizing its energy usage by smart controlling system(2018 IEEE International Conference on Industrial Electronics for Sustainable Energy Systems (IESES), 2018) De Zoysa, H.B.H.; Guruge, P.A; Kalingamudali, S.R.D; Kularatna, N.; Kanishka, G.Abstract: This paper outlines the methodology of designing and implementation of a solar powered system which can be used to make a human comfort zone during day time without using battery backup but with the use of Supercapacitors. Basically, major converter losses are reduced in this system. In acquiring a highly efficient power supply, the charge controller plays an important role. When a DC microgrid powers DC loads based on a renewable source such as a PV system; energy storage becomes mandatory due to fluctuating nature of the source. Localized DC-energy storage within DC-DC converters could address this requirement. A variation of supercapacitor assisted regulators could provide localized energy storage with low-noise and fast transient response [1]. 12 V LED lights will be powered from this system. LEDs can be powered directly via a supercapacitor bank from the regulated Photovoltaic energy. In the case of Inverter type Air Conditioner, in order to overcome converter losses, the DC Bus inside it should be accessed. Typically, DC Bus voltage inside the Variable Frequency Drive (VFD) is 1–414 times the supply voltage. Hence DC-DC Converters are used to power up the inside circuitry of the Inverter Air Conditioner from the solar panel. In order to optimize the energy usage and reduce electricity consumption, light dimming and air conditioning control systems were added to control the light intensity and switching of the air conditioner.Item Electrocatalytic activity of nanocubic and microcrystalline Cu2O electrodes for glucose oxidation(Sri Lanka Association for the Advancement of Science, 2016) Jayasinghe, J.L.K.; Jayathilaka, K.M.D.C.; Kaumal, M.N.; Dissanayake, D.P.; Jayanetti, J.K.D.S.Item Effects of lightning and possible health hazards due to the erection of telecommunication towers(Wayamba University of Sri Lanka, 2016) Maduranga, J.A.K.; Kalingamudali, S.R.D.; Jayaratne, K.P.S.C.The health hazards due to lightning and electromagnetic radiations in the neighbourhood of telecommunication towers were studied. Six tower sites were selected for the investigations from the areas covering the Sri Lankan lightning belt in Gampaha (Delgoda, Gonawala, Madarawa and Udupila) and Kaluthara (two in Poruwadanda) districts. Initially, a survey was conducted with a questionnaire based interviews. The earth resistance was measured using a digital earth tester according to the fall of potential method inside the region of 15m from the tower for studying the contribution to the lightning effects. The electromagnetic radiation power density was measured using a broadband field metre. The readings were obtained at 10m intervals along the direct line-of-sight of the antennas from the tower to about 80m distance. According to the literature and from the observations it was revealed that the most important factors related to the induced lightning current effect are the earthing systems utilised at the tower site, locations of the power feeding transformer and the houses in the neighbourhood. It was also observed that the earth resistance was near to threshold value in the Kaluthara district, and severe lightning hazards were prevented by installing the Surge Protection Devices (SPD) by the service providers. However, installing SPDs into houses was a temporary solution for the induced lightning current effects. The results of power densities showed that they were significantly below the recommended threshold values according to the guidelines of Telecommunication Regulatory Commission of Sri Lanka; such that the maximum and minimum were 0∙001% and 0∙0001% respectively. The measurements also revealed that distance from the tower is not the sole criteria to determine radiation hazards. In some regions the power density was independent from the distance from the tower because it was not proportional to the distance. In rural areas, the radiation power density emitted by the telecommunication towers is considerably low compared to that emitted by in-use mobile phones. Also, the radiation pattern is critically dependent on inclination and tilting direction of antennas. Thus, this study revealed that the effects of radiation emitted from telecommunication towers are negligible in the immediate neighbourhood.Item Surface treatment of electrodeposited n-type Cu2O thin films for applications in Cu2O based devices(2014) Jayathilaka, K.M.D.C.; Kapaklis, V.; Siripala, W.; Jayanetti, J.K.D.S.Item A quantum dot in topological insulator nanofilm(2014) Herath, T.M.; Hewageegana, P.; Apalkov, V.Item An Introduction to Quantum Mechanics(Stamford Lake (Pvt) Ltd., 2013) Punyasena, M.A.Item A double layered co-sensitization in dye sensitized solar cells (DSSCs) by using natural pigments(Sri Lanka Association for the Advancement of Science, 2015) Rathnasekara, R.E.; Dissanayaka, M.A.K.L.; Senadeera, G.K.R.