Research Papers - Department of Mechanical Engineering
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Publication Embargo Effects of carbon tax on greenhouse gas mitigation in Thailand(Taylor & Francis Group, 2008-01-01) Shrestha, R. M; Pradhan, S; Liyanage, M. HThis study analyses energy system development and the associated greenhouse gas emissions in Thailand under a reference case and three different carbon tax scenarios during 2013–2050 using a bottom-up cost-minimizing energy system model based on the Asia–Pacific Integrated Assessment Model (AIM/Enduse) framework. It considers the role of the renewable energy technologies as well as some emerging GHG-mitigating technologies, e.g. carbon capture and storage (CCS) in power generation, and GHG reduction in the country, and found that the power sector will play a major role in CO2 emission reduction. Under the carbon tax scenarios, most of the CO2 emission reduction (over 70%) will come from the power sector. The results also indicate the very significant potential for CO2 emission reduction through a significant change in the transport system of the country by shifting from low-occupancy personal modes of transport to electrified MRTS and railways.Publication Embargo Design and control of a high performance SCARA type robotic arm with rotary hydraulic actuators(IEEE, 2009-05-03) Liyanage, M. H; Krouglicof, N; Gosine, RThis study proposes a selective compliant assembly robotic arm (SCARA) with two revolute joints for poultry deboning. The joints of the arm are based on two high performance rotary type hydraulic actuators. These actuators are operated by servo valves, which control hydraulic fluid flow and direction. A PID based independent joint control system is considered for controlling the position of each joint. The system was modelled using the MATLAB-SIMULINK toolbox. The simulation results show that the arm was capable of covering a work envelope of 0.9 m times 0.9 m, reaching controlled velocities of up to 7.5 m/s with an average of 5.8 m/s. Obtaining such high speeds and torques would be a difficult task with electrical actuators of the capacity as the hydraulic counterparts considered here.Publication Embargo Scenario-based analyses of energy system development and its environmental implications in Thailand(Elsevier, 2007-06-01) Shrestha, R. M; Malla, S; Liyanage, M. HThailand is one of the fastest growing energy-intensive economies in Southeast Asia. To formulate sound energy policies in the country, it is important to understand the impact of energy use on the environment over the long-period. This study examines energy system development and its associated greenhouse gas and local air pollutant emissions under four scenarios in Thailand through the year 2050. The four scenarios involve different growth paths for economy, population, energy efficiency and penetration of renewable energy technologies. The paper assesses the changes in primary energy supply mix, sector-wise final energy demand, energy import dependency and CO2, SO2 and NOx emissions under four scenarios using end-use based Asia-Pacific Integrated Assessment Model (AIM/Enduse) of Thailand.Publication Embargo Factors affecting CO2 emission from the power sector of selected countries in Asia and the Pacific(Elsevier, 2009-06-01) Shrestha, R. M; Anandarajah, G; Liyanage, M. HThis study analyzes the key factors behind the CO2 emissions from the power sector in fifteen selected countries in Asia and the Pacific using the Log-Mean Divisia Index method of decomposition. The roles of changes in economic output, electricity intensity of the economy, fuel intensity of power generation and generation structure are examined in the evolution of CO2 emission from the power sector of the selected countries during 1980–2004. The study shows that the economic growth was the dominant factor behind the increase in CO2 emission in ten of the selected countries (i.e., Australia, China, India, Japan, Malaysia, Pakistan, South Korea, Singapore, Thailand and Vietnam, while the increasing electricity intensity of the economy was the main factor in three countries (Bangladesh, Indonesia and Philippines). Structural changes in power generation were found to be the main contributor to changes in the CO2 emission in the case of Sri Lanka and New Zealand.Publication Open Access A Cost Model for Evaluating Component Standardisation: A Case Study(O. P. A, 2000) Nagarur, N. N; Perera, H. S. C; Tabucanon, M. TAs manufacturing industry tries to grapple the oftenconflicting objectives of increasing product variety and reducing the production costs, one of the strategies oft contemplated is component standardization or using common components. However, developing and using standard components may sometimes push the overall costs actually higher. This paper proposes an evaluation model for decision making in the context of component standardization. First, it discusses various types of costs to be considered for selecting desired components. Then the paper presents a specific case study in which some purchasing parts are considered for standardization. An evaluation model is developed for the relevant costs of the case. The solution and sensitivity analysis are presented and discussed.Publication Embargo Analytic hierarchy process for selection of ERP software for manufacturing companies(SAGE Publications, 2008-10) Perera, H. S. C; Costa, W. K. REnterprise Resource Planning (ERP) systems are popular as an IT enabled tool, which integrates different functional areas of business. ERP systems are implemented as a total business solution that supports major functionalities of business. However, many of the implementations are not success stories. Most post implementation problems are due to the inappropriate selection of systems. This paper describes multi-criteria decision model using Analytic Hierarchy Process for the selection of ERP systems for manufacturing companies. First, ERP evaluation criteria are developed by using past literature and through a questionnaire distributed among Sri Lankan manufacturing companies. Seven major criteria are identified and under each criterion several sub-criteria are identified. Selection of the best suited ERP system leads to a multi-criteria decision making problem as ERP systems should be evaluated based upon many criteria. Using the identified main and sub criteria, an Analytic Hierarchy Process (AHP) model is developed for ranking the ERP software. An example of a case is presented to show the actual implementation of AHP model. Expert Choice software is used to solve this AHP model.Publication Embargo Economy wide emission impacts of carbon and energy tax in electricity supply industry: A case study on Sri Lanka(Pergamon, 2007-07-01) Siriwardena, K; Wijayatunga, P. D.C; Fernando, W.J.L.S; Shrestha, R. M; Attalage, R. AThis paper presents the results and analysis of a study conducted with the objective of investigating the impact on economy wide emissions due to carbon and energy taxes levied within the electricity generation sector of Sri Lanka. This exercise is mainly based on the input–output table developed by the national planning department. An input–output decomposition technique is used to analyze four types of effects that contribute to the overall reduction in equivalent carbon, NOx and SO2 emissions. These four effects are: fuel mix effect (i.e. the change in emissions due to variation I fuel mix), structural effect (i.e. change in emissions due to changes in technological coefficients with taxes compared to that without taxes), final demand effect (i.e. the change in emissions associated with changes in final demand) and joint effect (i.e. the interactive effect between or among the fuel mix, structural and final demand effects). The polluting fuel sources and low energy efficiency generation technologies are less preferred under these tax regimes. Of the four effects, a change in fuel mix in thermal electricity generation and a change final demand for electricity were found to be the main contributors in achieving economy wide emission reductions. It was found in the analysis that a minimum of US$ 50/tC tax or US$ 1.0/MBtu of energy tax is required to have a significant impact on economy wide emissions in the Sri Lankan context. This translates into an overall increase in electricity generation cost of approximately USCts 0.9 kW−1 h−1 and USCts 0.6 kW−1 h−1 under the carbon and energy tax regimes, respectively. The reduction in emissions is also strongly coupled with the value of the price elasticity of electricity.Publication Embargo Analysis of rural household energy supplies in Sri Lanka: energy efficiency, fuel switching and barriers to expansion(Pergamon, 2003-05-01) Attalage, R. A; Wijayatunga, Priyantha DCA majority of the households in Sri Lanka, as in the case of many developing countries, is concentrated in the rural areas of the country. Unfortunately, very little attention has been paid until recently to analyse and address various issues associated with rural energy supplies, particularly those issues regarding barriers to penetration of clean and convenient sources of energy. This paper presents the results and analysis of a study conducted through a sample study on domestic energy supplies in rural Sri Lanka with emphasis on cooking and lighting energy requirements. The paper has attempted to highlight policy issues associated with rural energy supplies and possible solutions to them in the context of the country’s overall picture of the energy sector.Publication Embargo Analysis of household cooking energy demand and its environmental impact in Sri Lanka(Pergamon, 2002-11-01) Attalage, R. A; Wijayatunga, Priyantha DCThis paper presents the results and analysis of a study conducted with the objective of investigating the cooking energy requirements in the Sri Lanka domestic sector and the environmental emissions associated with it. The study was conducted out through a sample and showed that the main household energy supply sources were biomass, liquefied petroleum gas (LPG), electricity and kerosene with electricity being used largely for water boiling in all subsectors. It was observed that the urban sector cooking is largely dominated by LPG (95% of urban households) while the rural sector cooking is confined mainly to biomass (95% of rural households). The suburban sector consists of a mixture of all the sources (LPG-70% and biomass-85% of suburban households). Similarly, LPG dominates in electrified households (76.4% of electrified households), while biomass dominates in all non-electrified households. It was found in the analysis that the highest level of gaseous emissions due to cooking activity occurs in the rural areas, mainly due to the relatively large use of biomass, while the lowest level of emissions is recorded in a typical suburban household. Also, the analysis shows that fuel switching in domestic cooking activities from biomass to LPG and kerosene can be used as a measure to reduce emissions due to higher stove efficiencies and lower emission factors associated with these fuels. Substitution of 50% of biomass usage by kerosene in the rural households will result in 39–50% reduction in emissions within the rural sector. Further, substitution of 50% of biomass usage in urban and suburban sectors by LPG results in 4–49% reduction in emissions within these sectors.Publication Embargo Socio-economic impact of solar home systems in rural Sri Lanka: a case-study(Elsevier, 2005-06-01) Attalage, R. A; Wijayatunga, Priyantha DCThe use of solar photovoltaic systems of 25 Wp to 50 Wp (frequently called solar home systems, or SHSs) has been spreading fast in the rural areas of Sri Lanka as a source of energy used for domestic lighting, mainly because of the financial incentives provided by the donor agencies and aggressive marketing strategies of the SHS dealers in rural areas. This paper presents the outcome and the analysis of a study conducted with the objective of investigating the social, economic and environmental impact of SHSs in rural Sri Lanka. The study involved conducting a survey of 125 households having SHSs, in the Uva province of Sri Lanka, through personal visits. It was evident that the households are extremely satisfied with the technology that has replaced their kerosene lamps, which had been providing household lighting requirements. The quality of life, in terms of activities such as longer study hours of children, longer TV watching hours for the family and lessening the risk of fatal kerosene lamp accidents, has improved with the introduction of the SHSs. It is concluded that the large-scale penetration of solar home systems in Sri Lanka has helped rural communities both in terms of improved socio-economic conditions and reduced adverse environmental impacts, contrary to the belief that the financial burden of such systems imposed on the families outweighs the benefits. But when comparing the benefits of SHSs against the extension of the national grid, the country needs to seriously examine its options for the areas currently targeted by SHS dealers.