Browsing by Author "Naveendra, J.A.L."

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    Development of a Low-cost pH Meter using Arduino Programming
    (Uva Wellassa University of Sri Lanka, 2021) Naveendra, J.A.L.; Jayawickrama, J.P.A.S.; Bandara, A.M.M.; Senarathna, K.G.C.
    A pH meter is an electronic device that measures the acidity or alkalinity of solutions by combining a pH sensor with a temperature sensor for a complete pH meter. The study was undertaken to create a low-cost pH meter with high accuracy. It is essential to measure accurate H+ ions in water-based solutions for various purposes such as aquaculture, water quality testing. The pH meter is an essential device for laboratories such as medicine, food, and agriculture. In today’s world pH meters are very expensive and need to pay more to buy a pH meter and that is a major issue for laboratories when importing pH meters. Different varieties of pH meters are commercially available in the market. The specialty of this research is the preparation of low cost of production nearly 6 times, compared to the commercially available similar pH meters. The designed pH meter is Arduino- based and the power supply via USB. Analog voltage signals are used to take the readings. A pH glass electrode sensor of a range of 0-14 and a DS18B20 temperature sensor was used. The voltages were measured by adding the pH sensor in pH 4.01, 7.01, and 10.01 standard buffer solutions. Then a graph of the pH vs. voltage was plotted and a mathematical model to calibrate the pH sensor was created using the piece-wise linear interpolation. The temperature sensor was calibrated at 0 and 100oC. The pH and temperature readings taken by the laboratory pH meters and thermometers were compared with the designed pH meter readings. The finalized device contains a menu especially for the calibrations and the adjustments by having major 4 sections as sensor calibrations, display settings, output mode, and the about device. The accuracy is up to 2 decimal points of pH and the stabilization values are given less than 30 seconds. It is identical to a pH meter found in a standard laboratory and the outcome of the study is a low-cost pH meter. Because of its user-friendly interface, simple calibration process, and high level of accuracy at a reasonable price, the pH meter can be used instead of existing pH meters. Keywords: pH meter; Low-cost pH meter; pH sensor calibration; Temperature sensor calibration; Piece-wise linear interpolation
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    Utilization of Sugarcane Bagasse Ash as a Partial Replacement of Fine Aggregate in Grade 45 Concrete
    (Uva Wellassa University of Sri Lanka, 2021) Himasara, P.A.H.S.; Thannahena, T.H.D.D.; Naveendra, J.A.L.; Senarathne, K.G.C.
    Nowadays, many investigations focus on ways of utilizing industrial or agricultural wastes as a replacement for the construction industry. In addition to the financial benefits in this regard, such materials may also lead to sustainable products and a pollution-free environment. Sugarcane bagasse ash is one such siliceous and aluminous waste generated in the sugar refining industry apart from ethanol. In this study, fine aggregates in a concrete mixture were partially replaced by untreated sugarcane bagasse ash under different weight percentages: 0%, 10%, 20% and 30%. The untreated bagasse ash was also used as another raw material in the concrete mix apart from other raw materials: fine aggregates, coarse aggregates, cement and water. The compressive strength measured at 28 days was considered to determine the optimum ash content for the concrete mix. In this optimum range, the highest value range for compressive strength is found. Accordingly, the optimum ash content should be between 0% - 10%, if sugarcane bagasse is used as a partial replacement to fine aggregates. However, when added in addition to the existing materials (without partial replacement), the outcomes for the compressive strength have not found to be favourable. The compressive strength is comparatively low in this case compared to the full replacement scenario. This study thus concludes that high strength concrete can be made by utilizing sugarcane bagasse ash as a partial replacement of fine aggregate. Keywords: Compressive strength; Sugarcane bagasse ash; Sugarcane bagasse; Agricultural waste