Browsing by Author "Perera, TM"

Now showing 1 - 11 of 11

item: Conference-Full-text
Assessing the cracks developed in Dematamal Viharaya, Butthala
(Department of Civil Engineering, University of Moratuwa, Sri Lanka., 2011-12) Jayasinghe, MTR; Paskaran, S; Perera, TM; Kumara, D; Ratnayake, N
Stupas of Sri Lanka stand as proud examples for the engineering excellence of ancient Sri Lanka. Dematamal Viharaya at Butthala is one of the oldest stupas in Sri Lanka built in the 2nd Century BC which is a, 19m tall non-plastered brick structure. This stupa has developed cracks since 1998. Cracks have initiated from the pesawalalu and propagate to the top of the dome. The research covered in this report is aimed at the identification of the A comprehensive study was carried out to identify the possible causes for the cracks which may be due to self weight and shape of the stupa, expansive nature of soil, arch action induced due to separation of old and modern masonry. Experiments were done to assess the expansive nature of the soil and a Finite element analysis was carried out using the Finite element software SAP2000. The results revealed that the possible cause may be the arch action induced due to separation of old and modern masonry.
item: Conference-Full-text
Effect of Chemicals used in Building Operation on Indoor air Quality (IAQ)
(2016-05-26) Perera, TM; Jayasinghe, C
Better quality of air is one of the basic needs for every human being. Since the people spend most of the time inside the buildings, indoor air quality is a critical factor on occupant health. If the indoor environment is polluted, the occupants may experience number of possible health conditions such as sneezing, fatigue, headache, dizziness, nausea, irritability, and respiratory diseases as asthma. Also, long term exposure into the pollutants can cause more serious health effects. Therefore it is very important to maintain a high degree of hygienic level in all our buildings by identifying the indoor pollute sources and achieving a proper design of ventilation system in the indoor environment. The aim of this research is to find out the IAQ variation due to a selected set of chemicals used in building operation in the daily routines. The emission from the sources of mosquito coil, naphthalene ball, open waste burning (Dry leaves and Polythene) and air freshener were tested under controlled environmental conditions and a case study was carried out in a service center where a significant amount of chemicals are used in the daily activities. Indoor Air Quality Monitor (IQM60 Environmental Monitor V5.0) and Haz-Dust Particulate Air Monitor were used to measure the concentration of Carbon Monoxide (CO), Carbon Dioxide (CO2), Nitrogen Dioxide (NO2), Total Volatile Organic Compounds (TVOCs), Particulate Matter (PM2.5), temperature and relative humidity during the experiments. The results revealed that high concentrations of TVOC inside the motor vehicle service center during the entire working hours. Therefore it is essential to consider the indoor activities during the design stage. Also, it is highlighted that the paramount importance of the proper ventilation condition since there are frequently use of indoor air pollute sources in daily usage.
item: Conference-Full-text
Effect of the Activities Inside a Hospital Theatre of its IAQ
(2016-05-26) Gunaratne, WDSP; Gunatilake, MMDV; Jayasinghe, C; Madushanka, HKR; Perera, TM; Perera, SAS; Rajapaksa, S
A close relationship can be observed between the building performance and the activities associated with the building. Since those activities have a great impact on Indoor Air Quality (IAQ) of the building, it is necessary to consider the activities that would take place inside a building, at its design stage. In this research study, the effect of the activities associated with a hospital theatre, on its IAQ has been studied since the theatre staff of a leading hospital in Sri Lanka, experience some discomfort while being inside the theatre. In order to evaluate this, variation of Carbon Dioxide (CO2), Carbon Monoxide (CO), Total Volatile Organic Compounds (TVOC) and Particulate Matter less than 2.5 microns (PM2.5) concentrations inside the theatre were measured and analysed. Significant variations were observed in the concentrations of CO2, TVOC and CO inside the operation theatre. CO2 concentration inside the room increased at the beginning and end of the surgeries due to high occupant density and also during Laparoscopic surgeries. TVOC concentration was affected by the usage of different chemicals during the surgery. Major effect to the CO concentration was by Diathermy.
item: Conference-Full-text
Indoor air quality (IAQ) inside a hospital theatre
(Department of Civil Engineering, University of Moratuwa, 2012-12) Gunaratne, S; Gunatilake, D; Madushanka, R; Perera, TM; Jayasinghe, C; Perera, A; Rajapaksa, S; Nawagamuwa, U; De Silva, LIN
In this research study, the effect Abstract: of the activities associated with a hospital theatre, on its IAQ has been studied since the theatre staff experience some discomfort while being inside the theatre. In order to evaluate this, variation of Carbon Dioxide (CO:), Carbon Monoxide (CO), Total Volatile Organic Compounds (TVOC) and Particulate Matter less than 2.5 microns (PM25) concentrations inside the theatre were measured and analyzed. Significant variations were observed in the concentrations of CO:, TVOC and CO inside the operation theatre. CO2 concentration inside the room increased at the beginning and end of the surgeries due to high occupant density and also during Laparoscopic surgeries. TVOC concentration was affected by the usage of different chemicals during the surgery. Major effect to the CO concentration was by Diathermy.
item: Conference-Full-text
Indoor air quality and human activities in buildings
(2013-11-09) Perera, TM; Jayasinghe, C; Perera, SAS; Rajapaksa, SW
People spend most of their time indoors either at home or at work. If the indoor environment is polluted, the occupants may experience number of possible health conditions such as sneezing, fatigue, headache, dizziness, nausea, irritability, and respiratory diseases as asthma. Also, long term exposure into the pollutants can cause more serious health effects. Therefore it is very important to maintain a high degree of hygienic level in all our buildings by achieving a proper design and maintaining an adequate ventilation system in the indoor environment. There are different types of ventilation that can be used in the indoor environment such as free running systems by opening windows and doors, fans and air conditioners. But due to the poor operational practices in the modern buildings such as restricting free ventilation by closing doors and windows in most of the time and no proper maintenance in the air conditioning system may pollute the indoor environment. Therefore numerous forms of indoor air pollution are possible in the modern buildings. In this paper, recent research is revised on effect of air freshener and tobacco smoke on indoor environment with modern operational practices.
item: Conference-Abstract
International Conference on Structural Engineering and Construction Management
(2015-05-19) Jayasinghe, C; Perera, TM; Perera, SAS
A deployable structure should mainly be adequately compact and should fit into any remaining space of the launch vehicle. The main factors which will determine these are the folding pattern,ease of deployment and stresses in the fold lines. Two folding patterns are selected based on extensive literature review to investigate the possibility of using those techniques for a large solar sail mission. It is expensive as well as extremely time consuming to perform experimental investigation under reduced gravity environment for this type of large membranes. Thus developing simulating techniques are quite important. Two models are simulated using Abaqus/Explicit commercial finite element software. Quasi-static conditions and numerical accuracy are verified by comparing strain energy together with kinetic energy and artificial strain energy. It is shown that spiral folding pattern requires less energy for deployment and hence that is preferred.
item: Conference-Abstract
Investigation of cracks developed in Dematamal Viharaya, Buttala
(2011) Paskaran, S; Perera, TM; Kumara, SDS; Jayasinghe, MTR; Jayasinghe, C; Lewangamage, CS
Dematamal Viharaya of Buttala is one of the oldest Stupas in Sri Lanka built in the 2nd Century BC. It is a !8m tall non-plastered brick structure. This Stupa has developed some cracks in the recent past. Cracks have initiated from the Pesawalalu to the top of the Dome, The research covered in this paper was aimed at the identification of the causes for the cracks and to propose corrective actions. A comprehensive study was carried out to identify' the possible causes for the cracks which may be due to settlement of the foundation, expansive nature of soil, self weight of structure or the separation of the old and new parts of the Stupa. Tests were done to assess the expansive nature of the soil and a detailed analysis was carried out using SAP2000 to test the other two hypotheses. The results revealed that the possible cause could be the contraction of the old brick work beneath the new brick work and the discontinuity between them. Based on the identified causes corrective actions have been proposed.
item: Conference-Abstract
Measurement and analysis of concentrations of volatile organic compounds in a newly painted room
(2016-08-10) Jayasinghe, C; Perera, SAS; Rajapaksa, SW; Perera, TM
Since, people spend most of their times indoors, either at home or at work, it is essential to maintain a high level of health and safety inside all types of buildings. If the health conditions of occupants are adversely affected due to the indoor environment, it is called the sick building syndrome (SBS). The main causes of SBS are, bad planning of a building, which leads to, poor ventilation, higher temperature, higher humidity, poor building operational practices and emissions from building materials. Air pollutants due to building materials can include paints and coatings which may emit harmful chemicals. Further the emissions from building maintenance chemicals, such as, detergents, disinfectants, antiseptics and air fresheners can pollute the indoor environment. The main objective of the research covered in this paper is to measure concentrations of gaseous emissions from water based and solvent based paints, during the painting process and immediately after painting and to compare results with air quality standards. The Indoor Air Quality Monitor (IQM60/Environmental Monitor V5.0) was used to measure concentrations of gaseous emissions. The results indicated that the concentration of TVOC (Total Volatile Organic Compounds) has increased during the painting process and the time taken for the emissions to get dispersed and the air quality of the room to get back to the permissible level has been found to be more than two hours.
item: Conference-Full-text
Measurement and analysis of concentrations of volatile organic compounds in a newly painted room
(2013-11-13) Jayasinghe, C; Perera, SAS; Rajapaksa, SW; Perera, TM
Since, people spend most of their times indoors, either at home or at work, it is essential to maintain a high level of health and safety inside all types of buildings. If the health conditions of occupants are adversely affected due to the indoor environment, it is called the sick building syndrome (SBS). The main causes of SBS are, bad planning of a building, which leads to, poor ventilation, higher temperature, higher humidity, poor building operational practices and emissions from building materials. Air pollutants due to building materials can include paints and coatings which may emit harmful chemicals. Further the emissions from building maintenance chemicals, such as, detergents, disinfectants, antiseptics and air fresheners can pollute the indoor environment. The main objective of the research covered in this paper is to measure concentrations of gaseous emissions from water based and solvent based paints, during the painting process and immediately after painting and to compare results with air quality standards. The Indoor Air Quality Monitor (IQM60/Environmental Monitor V5.0) was used to measure concentrations of gaseous emissions. The results indicated that the concentration of TVOC (Total Volatile Organic Compounds) has increased during the painting process and the time taken for the emissions to get dispersed and the air quality of the room to get back to the permissible level has been found to be more than two hours.
item: Conference-Full-text
Measurement and analysis of indoor air pollutants in a room sprayed with a locally manufactured air freshener
(2013-11-13) Perera, SAS; Jayasinghe, C; Gunaratne, WDSP; Gunatilake, MMDV; Madushanka, HKR; Perera, TM
In the modern world, since, people like to live, work and travel in, aesthetically pleasing, comfortable environments with pleasant odour, they tend to use, decorative interiors, air conditioners and air fresheners, whereas, during good old days, natural alternatives, such as, natural ventilation, natural fragrances and natural interiors were used to make living comfortable. Today, in most of the indoor environments, air fresheners are sprayed, to give a pleasant odour. This is practiced in most commercial buildings, factories, houses, as well as, cars and other modes of transport. However, many studies conducted by researchers, internationally, have. revealed that many chemicals are used in the manufacture of air fresheners, some of which, might have adverse impacts on human health. The main objective of this research project was to measure and analyse concentrations of Carbon Dioxide (CO2), Carbon Monoxide (CO), Total Volatile Organic Compounds (TVOC) and Particulate Matter less than 2.5 microns (PM2.5), due to the spray of air freshener into an air conditioned office room, with no external air circulation. To make the research relevant to Sri Lanka, a locally manufactured, popular brand of air freshener packed in a non pressurised finger operated spray bottle, was used to spray air freshener into the room. The results have revealed that, the indoor air TVOC levels can significantly rise beyond permissible limits, in an air conditioned room, with no external air circulation.
item: Conference-Abstract
Measurement and analysis of indoor air pollutants in a room sprayed with a locally manufactured airfreshener
(2016-08-10) Perera, SAS; Jayasinghe, C; Gunaratne, WDSP; Gunatilake, MMDV; Madushanka, HKR; Perera, TM
In the modern world, since, people like to live, work and travel in, aesthetically pleasing, comfortable environments with pleasant odour, they tend to use, decorative interiors, air conditioners and air fresheners, whereas, during good old days, natural alternatives, such as, natural ventilation, natural fragrances and natural interiors were used to make living comfortable. Today, in most of the indoor environments, air fresheners are prayed, to give a pleasant odour. This is practiced in most commercial buildings, factories, houses, as well as, cars and other modes of transport. However, many studies conducted by researchers, internationally, have. revealed that many chemicals are used in the manufacture of air fresheners, some of which, might have adverse impacts on human health. The main objective of this research project was to measure and analyse concentrations of Carbon Dioxide (CO2), Carbon Monoxide (CO), Total Volatile Organic Compounds (TVOC) and Particulate Matter less than 2.5 microns (PM2.5), due to the spray of air freshener into an air conditioned office room, with no external air circulation. To make the research relevant to Sri Lanka, a locally manufactured, popular brand of air freshener packed in a non pressurised finger operated spray bottle, was used to spray air freshener into the room. The results have revealed that, the indoor air TVOC levels can significantly rise beyond permissible limits, in an air conditioned room, with no external air circulation.