https://ir.kdu.ac.lk/handle/345/5835 2026-04-06T09:01:01Z https://ir.kdu.ac.lk/handle/345/6043 A Modified Green Building Rating System to Evaluate Sustainability Aspects in Residential Apartments in Sri Lanka Thiwanka, SPD; Halwatura, D; Pallewatta, N Residential apartments have been identified as the most popular solution for the rapid increase of population in urban cities. However, in some cases, sustainability aspects (environmental, social and economic) of these apartments are abandoned. Further, there is no unique system to evaluate the sustainability of these apartments in Sri Lanka, and most international green building rating systems have unequal point distribution among sustainability subsets, which causes heterogeneity among subsets. Thus, this research was designed to develop a modified sustainable rating system for residential apartments in Sri Lanka, thereby reducing the sustainable subset heterogeneity by introducing modified point distribution percentages (Environment [40%], Social and Economic [30%]). The apartments certified under the GREENSL rating system for the built environment were selected as three case studies. The claimed points for GREENSL certification by GREENSL Platinum, Gold and Silver-rated apartments were evaluated under the three sustainability subsets. The results revealed that three subsets were not equally considered in the GREENSL rating system (Platinum-rated: Environment [50%], Social [21.6%], Economic [28.4%]; Gold-rated: Environment [50%] Social [29.5%) Economic [20.5%]; Silverrated: Environment [47.6%] Social [27.8%] Economic [24.6%]). Further, the sustainability status is satisfactory in the social dimension, irrespective of the level of certification. Based on the findings, a modified rating system was developed for residential apartments by adopting new sustainability criteria including compartmentalisation, interior moisture management, air purification, enhancing acoustic performance and disaster risk reduction. The study revealed that sustainability practices of residential apartments in Sri Lanka need further improvement, while providing more weight on social and economic pillars. 2022-09-29T00:00:00Z https://ir.kdu.ac.lk/handle/345/6042 Evaluation of Growth, Yield and Nitrogen Losses from Leafy Red Onion Cultivation with Different Fertilizer Practices in Kalpitiya Peninsula Swarnathilake, DSGGC; Dalpitiya, DMAU; Herath, HMIK; Gimhani, DR Intensive agriculture practices together with increased fertilizer use have a greater impact on groundwater quality in Kalpitiya. Water demand in Kalpitiya is 70%, fulfilled by groundwater extractions. The permeable nature of sandy Regosols causes leaching of nutrients and contamination of shallow groundwater. The aim of this study was to evaluate the effects of different fertilizer practices on growth, yield and nutrient leaching in leafy red onion grown in Kalpitiya. The red onion is the major crop grown in large scale. The treatments tested were T1-Farmer Used Rate of fertilizer and T2-Department of Agriculture recommendation. The experiment was arranged in Completely Randomised Block Design with three replicates in six plots (7.2m2). The red variety of Jaffna Local was established in a research field where lysimeters were previously installed. The leachate was collected weekly from lysimeters and analysed for leached nitrogen. Growth of plants and yield were recorded. A significant difference in leached nitrogen was observed between treatments. Furthermore, it was observed that there was a statistically significant difference between the final yield of T1 and T2 treatments. The total nitrogen leaching percentage of T2(67.88%) was lower than T1(78.86%), even though the crop yield of T2 (5069.25kg/ac) was lower than T1(7556.95kg/ac). The average concentration of nitrate in the leachate of T1 was 73mg/l, while that of T2 was 72mg/l. The safe limit of nitrate in groundwater is 50mg/l. Recommended amounts of fertilizer should be applied in balanced proportion and at appropriate times with soil amendments, which may help to absorb nutrients efficiently. Therefore, the study concludes that both practices showed leached nitrate concentrations above safe limits recommended by WHO, which urges the need for change in nitrogen fertilizer management for red onion on sandy regosols. 2022-09-29T00:00:00Z https://ir.kdu.ac.lk/handle/345/6041 Secure Data Transformation in Cloud Using Hybrid Cryptography Hansika, EBT; Upeksha, RGC; Weerawardane, TL The Cloud is a very well-known and accepted data storage that provides many benefits to users with a pay-as-you-go pricing model, even providing storage solutions for massive amounts of data. Many users nowadays use different Cloud services, mainly because the data can be accessed from anywhere via the internet. Cloud servers are located all over the world, storing massive amounts of data. When a user uploads or downloads from the Cloud server, the data is exposed to the internet. This can lead to security issues, such as unauthorised disclosure of data and lack of user privacy if the data is not properly protected. Many cryptographic algorithms are used to secure data transformation in the Cloud. The proposed system is designed to offer a method for properly securing data when transferring them to the Cloud, utilising various cryptographic techniques, and integrating them most innovatively and effectively considering the security, data integrity, speed and data confidentiality. The data is encrypted using a combination of three algorithms namely AES, ECC and RSA by increasing the security of the data. The keys generated by the ECC and RSA are combined using an Exclusive OR gate. The AES key is uploaded into the key management server after being encrypted by the newly generated key. The data encrypted by the AES key are uploaded into the Cloud storage. The proposed system is intended to distinguish the features and functionalities to overcome the drawbacks of the current systems. 2022-09-29T00:00:00Z https://ir.kdu.ac.lk/handle/345/6028 Identifying an Air-Conditioned Room’s Comfortable Zone with Respect to the Room Dimensions and Position of A/C Unit Mounted Vithanage, VN; Jayathilaka, HMKP; Nimali, MSD; Jayamini, HPA The goal of the study project is to assess the thermal comfort in the Mechanical Lecture Room (MLR) at Faculty of Engineering, University of Ruhuna in order to find the comfortable zone in that air-conditioned room. The subject room with dimensions of 14.66m x 5.10m x 5.13m and set up with two 36000Btu/h Split Type air conditioners were tested. The room air temperature varied from 18.5 Celsius to 24.6 Celsius, when both A/C machines were operating at 17 Celsius. The length of the MLR was divided into 12 parts, while the width was divided into 6 equal parts. The Temperature values were taken by using 10 J-type thermos couples. The findings of this study can be used to build and control air-conditioning systems for the identification of a room's comfort zone in relation to the size of the space and where the air conditioner is positioned. 2022-09-29T00:00:00Z