UWU Repository :: Browsing by Author "Jayasinghe, G.Y."

Browsing by Author "Jayasinghe, G.Y."

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Assessment of the Plant Growth Performances of Vertical Green Walls Developed with Different Plant Types in a Tropical Climate
(Uva Wellassa University of Sri Lanka, 2018) Perera, T.A.N.T.; Halwatura, R.U.; Jayasinghe, G.Y.; Rupasinghe, H.T.
Planting on roofs and walls seems to be a modern and swiftly developing strategy towards sustainable environmental constructions. Covering building with vegetation enhance the city environment in terms of contributing to urban biodiversity, growing thermal comfort by buffering building temperature and mitigation of the Urban Heat Island (UHI). The study observed the significance of urban vegetation cover with the objectives of selecting suitable plant types for selected medium on vertical green wall panel by investigating the different plant physiological parameters. Fabrications of green wall panels were done in the premises of Department of Civil Engineering, University of Moratuwa by using timber frames (60 x 30cm) filled with coir dust growing medium for 2.5 cm thickness and fixed with wire mesh. Few holes at the bottom of the panel was prepared to facilitate water drainage. Each panel was irrigated three times per week with 0.5 liter of water per each panel. Nutrient solution prepared by dissolving 0.5 g of Albert's mixture in 500 ml of water for each panel and applied two times per week. Experimental design was Completely Randomized Design (CRD) with 3 replicates from each plant species. The nine plant species (treatments) were placed in green wall panel. Each panel (replicates) held eight plants of each species. Desmodium triflorum, Roheo spathacea, Centella asiatica, Axonopus fissifoliu, Axonopus compressus, Elusine indica, Dieffenbachiae spp, Tectaria spp, Bigonia spp were the selected plant species for the study. Plant health was rated for all plants using a 3 point scale. 1 = thriving, 2 = alive, but with signs of pest, disease or other stresses, 3 = dead. Plant height and leaf area were measured along with visual assessments of plant development stages and pest/disease incidence. Roheo spathacea, Elusine indica, Axonopus fissifolius displayed the greatest survival (100%) and coverage on an extensive green wall. Increment of Leaf Area Index of nine species over the eight weeks was significantly different (P < 0.05) among each species. Highest LAI obtained from Roheo spathacea (3.99) followed by Axonopus compressus (0.99), Elusine indica (0.76), Axonopus fissifolius (0.44),) over the trial period. In terms of actual performance, Roheo spathacea, Elusine indica, Axonopus fissifolius displayed the greatest survival and coverage on an extensive green wall.
Identification of Thermal Hot Spots in Urban Areas through Establishing Heat Index in Support of Mitigation Plans to Counteract Urban Heat Island (UHI): A Case Study in Colombo Urban Area – Sri Lanka
(Uva Wellassa University of Sri Lanka, 2020) Perera, T.A.N.T; Nayanajith, T.M.D.; Premasiri, H.D.S.; Jayasinghe, G.Y.
The creation of thermally comfortable microclimates in urban environments is very essential for human well-being. This study was conducted to assess the outdoor thermal comfort by establishing Heat Index (HI) values and identifying thermal hot spots in Colombo urban city of Sri Lanka. Fourteen sites (14) with different urban designs were selected purposively which were highly populated during daytime. Daytime temperature and humidity values of selected locations were collected to calculate HI values. Further, questioner surveys were conducted among 168 individuals purposively to evaluate the thermal perception of people who exposed to outdoor thermal conditions. Five study sites (Borella, Colombo Fort, Maradana, Wellawaththa, Liberty junction) out of 14 selected study sites were identified as thermal hotspots in Colombo. The average day time HI value for Colombo city was 37.36°C during the study period. The observed HI values were varied between 40.35°C-33.82°C. The highest average day time HI value was observed at Maradana (40.35°C) and lowest HI at Thummulla (33.82°C). The questionnaire survey was revealed most of the study sites consisted of uncomfortable outdoor thermal conditions and people prefer windier, shady, and low temperature outdoor micro climatic conditions in Colombo. The study was revealed that the most important feature of public spaces is the availability of shade due to the intense solar radiation. It is important to promote an urban design that creates shade and ventilation. Keywords: Heat index; Outdoor thermal comfort; Thermal hotspot; Urban micro-climate
Impacts of Southern Expressway towards Flood Condition Changes: A Case Study in Dodangoda Divisional Secretariat.
(Uva Wellassa University of Sri Lanka, 2019-02) Sankalani, M.G.P.; Jayasinghe, G.Y.
Road infrastructure can be considered as a backbone in terms of both passenger and freight transport. With the construction of expressways, it contributes to undoubted social and economic development of a country. Southern expressway is the Sri Lanka’s first expressway experience and now it is under expansion stage. Though people emphasis the positive influence, it is worth to mention the negative impacts of expressway construction. Hydrology and drainage changes, water quality and quantity changes, air quality and vibration impacts, habitat fragmentation and direct mortality of animals are determined as examples for negative impacts. Frequent floods even in small rainfalls are common around the expressways now. This paper elaborates changes in flood condition of the study area due to expressway construction. Field questionnaire survey for 63 families was conducted on the flood affected people who surrounded the expressway in selected Grama Niladhari Divisions within study area. Survey reveals that expressway is acting as barrier for the free flow of water in flood conditions and new flood inundated areas are created as a result. The data shows 89% of the people along the 400 m road strip are experienced changes of flood conditions after the expressway construction. Improper culvert construction, poor maintenance, previous drainage pattern changes, and wetland fillings are altered flood conditions along the expressways. Thus, suburbanization of lands along the expressway has created impervious land layers by increasing runoff and finally creating urban floods. However, more environmental considerations are needed in order to promote sustainability in constructions. Although we are unfamiliar, some countries such as USA are considered their ecological sustainability even by green road rating systems. Therefore, it is timely requirement to concern those impacts in constructing expressway network in Sri La
Implementation of low cost, automated, mobile monitoring module by means of AI for container gardening in urban areas
(Uva Wellassa University of Sri Lanka, 2020) Madhusanka, P.B.H.; Perera, T.A.N.T.; Piyasena, P.; Jayasinghe, G.Y.
The limited amount of space and climate variability have led to the emergence of urban agriculture mainly in agricultural countries. This has turned urban gardens to be smart, autonomous, and efficient with the trend towards interconnected devices. The main objective of this study is to build an IoT based low cost, automated, mobile monitoring module for container gardening in urban areas. This system built with NodeMCU ESP-32 has been designed and successfully examined during the study. In constructing of the device, several sensors sych as environmental humidity and temperature, light, Passive Infrared Sensor (PIR), soil temperature, soil moisture sensors and a base station connecting the cloud to the whole network were used. The system will track plants on a mobile device which has the capability of providing real-time updates on crop conditions through the internet (Thinkspeak). The device is capable of measuring five parameters (soil moisture, temperature of soil & air, air humidity and light intensity) at once and show all the parameters on the ThingSpeak site for user to get the idea and also this controls the light level and soil moisture levels of the pot automatically. The acquired results have been shown the performance of the device is precise. Such as collecting, logging and analyzing the irregular data from the sensors. Consequently the system is beneficial and cost effective for the commercial scale farmers as well. Farmers can be monitor their field without wasting time and resources with the help of several sensors and the alert system. With the automatic irrigation system help to reduce water wastage and it allows to use water efficiently. Therefore, the device is efficient both the farmer’s as well as environment in concentration. Keywords: Artificial intelligence, NodeMCU ESP-32, Smart gardening, Sustainability, Urban agriculture
Poultry Litter Generation, its Impacts and Management Strategies in Sri Lanka – A Review
(Uva Wellassa University of Sri Lanka, 2019-02) Maheepala, S.A.D.S.S.; Jayasinghe, G.Y.
The poultry sector has been increasing at more than 5% per annum in last 3 decades to complete the increasing demand of safer and high quality meat and eggs. This development has been go along with structural changes within the sector as industrial farming establishments, the intensification and concentration of poultry operations. The poultry sector contributed to 0.35% of national GDP which is more than 50% of total livestock sector contribution in Sri Lanka. The per capita meat chicken availability in Sri Lanka was 10 kg/year in 2017. Kurunagala, Puttalm and Gampaha districts are accounted as the highest poultry farm located districts in the country. Concentration of large amount of manure is accounted as a major environmental issue which emerged with poor manuremanagement practices such as burning, direct usage as a fertilizer, etc. Substantial amounts of nutrients such as N, P and excreted substances such as hormones, antibiotics, pathogens and heavy metals are contained in poultry manure which are introduced through feed. The limited access of land to dispose manure increases the concentration of manure at one place and results soil and water pollution. Direct application of poultry litter into crop fields releases large amount of N and some other nutrients together with pathogens and other microorganisms into the environment. The substances which are contained in the litter are broken down, immobilized or transformed to the water, soil and atmosphere. Different forms of N such as ammonia (NH3), dinitrogen (N2), nitrous oxide (N2O) and nitrate (NO3-) are emitted by manure and increase the N footprint. The surface application of poultry litter increases greenhouse gas emission and results global environmental issues such as global warming, climate change, eco system degradation, etc. Moreover, manure consists considerable amount of toxic metals such as arsenic, copper and zinc. Excessive amount of elements harm to crops and adversely affect on animals due to bioaccumulation. Scientists are focusing on efficient technologies to produce bio fertilizer from poultry litter to reduce the negative consequences which are caused by inappropriate poultry litter disposal methods.
Unmanned Arial Vehicles (UAV) in Smart Agriculture: Trends, Benefits and Future Perspectives
(Uva Wellassa University of Sri Lanka, 2019) Perera, T.A.N.T.; Priyankara, A.C.P.; Jayasinghe, G.Y.
There is an improved concern in precision farming and the development of smart systems for agricultural resources management aims to increase the agricultural productivity, optimize the profitability, and protect the environment. Data collection, field variability mapping, decision making, and management practices are the foremost stages of smart agriculture. Self-directed aircrafts are sophisticated cost effective instruments for data acquisition, real time thermal images to the Ground Control Station (GCS), and the best medium for quick time and critical analysis of the crop growth. Unmanned Arial Vehicles (UAVs), especially drones, can fly autonomously with dedicated software which allows making a flight plan and deploying the system with Global Positioning System (GPS) and feed in different parameters such as speed, altitude, Region of Interest (ROI). These features are required in smart agriculture where large areas are monitored and analyses are carried out in minimum time with miniaturization of compact cameras and other sensors like infrared and sonar. UAVs are presently being functional by farmers in extensive field analysis of crop behavior such as rice, maize and wheat where they scan through the field, take images and report abnormality. The collection and delivery of images in a timely manner, the lack of high spatial resolution data, image interpretation and data extraction issues are the major limitations identified in the applications of remote sensing systems in agriculture. Nevertheless the future of agriculture is clear with drones as a precious tool that will amplify profitability and healthy crop production. Further, it has been predicted that the agriculture sector will be the second largest user of drones in the world in the next five years. Research priorities and future challenges that will support in the development of effective use of UAV in agriculture with multi-prong strategies were discussed.
Urban Green Infrastructures as an Integrative Approach for Sustainable City Planning and Development in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019-02) Galagoda, R.U.; Jayasinghe, G.Y.
Sustainable urban planning and development denotes the quality improvement of life through engineered environmental, social and economic constituents concerning the life standards of future generation. Population density within Sri Lanka’s capital; Colombo, is higher as 18,900 populations per km2 and has experienced 0.09 – 4.4oC urban heat island effect during 2012. Since land use has been changed periodically by urbanization and industrial expansion, unplanned grey infrastructures have resulted downgraded environment with sudden natural calamities which challenge livability in Colombo city. Hence, the objective of this paper is to review the significance, present status and future perspectives of urban Green Infrastructure (GI) as an integrative approach for sustainable city planning and development in Sri Lanka. GIs are multi-functional approaches for ecological equilibration and sustainability in urban context. Rain gardens, living roofs, urban forestry and vertical gardens are few of GI that has widely been implemented worldwide. Green walls are superior in temperature reduction, air purification and energy conservation at building micro-climate. Most developed countries are strict with national planning policies concordance with environmental protection agencies, sustainable development goals and ISO 31720 standard for resilient and sustainable cities. Sri Lankan government recently paid attention on sustainable urban development with multi model transport hubs, metro Colombo urban development projects as integrated flood management systems, rehabilitation and implementation of urban public facilities. Positively, urban development authority leads future development strategies counting landscaping, traffic impact assessment and water management systems raising social awareness. However, integrated holistic city – scale approaches of GI in urban planning should be encouraged by local government through mandatory policies ensuring socio – economic benefits beside cling to certain notions.
Utilization of Sustainable Timber Materials for Innovative Green Building Solutions
(Uva Wellassa University of Sri Lanka, 2019-02) Dissanayake, D.M.N.A.; Mendis, M.S.; Jayasinghe, G.Y.; Halwatura, R.U.
The demand for timber, as a sustainable construction material is projected to increase over the next half century with the massive development of the construction sector. Sustainable timber denotes to timber that has been harvested responsibly from well-managed, continuously replenished forests with no damage to surrounding environment. Industrial roundwood consumption, including timber, will be increased by 28% to 61% from 2010 to 2060. With mounting pressure to decrease the carbon footprint of the built environment, building designers are progressively being called upon to balance functionality and cost objectives with reduced environmental impact. Timber can help to achieve that balance. It is exciting to note that in response to the Paris Agreement (COP21), scientists proposed a range of “negative emissions technologies (NETs) in order to limit climate change to “well below 2C”, three of which relate to timber and its capacity to absorb and store carbon from the atmosphere: afforestation and reforestation, building with biomass and biomass with carbon capture and storage. Timber can be regarded as the best construction material because it has following characteristics: carbon capture and storage, low embodied energy, truly renewable, durable and easily maintained, beautiful aesthetic, highly versatile, quick and simple build, good insulation, can use scrap and salvaged wood, non-toxic, humidity regulator and priceless habitats. In addition, timber has provided several other ecological services beside helping to combat climate change and being wildlife havens. They reduce the risk of flooding, drought, soil erosion and assist to stabilize and regulate weather and micro-climates. The objective of this research is to examine the global tendency of timber as a sustainable green building construction material, its present status, challenges, its impacts on the climate change and future perspectives.

Browsing by Author "Jayasinghe, G.Y."

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