45 research outputs found

    Modeling Community Quality of Life Indicators for Developing Solar Home System in Remote Areas

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    AbstractThis paper proposes the modeling indicators of quality of life of those communities in remote areas which received the Solar Home System (SHS) benefit. The questionnaire was designed by survey method using in-depth interview from the professional trainee. The surveyed data was classified using the Analysis Hierarchy Process (AHP) method. The target group was classified into three groups, namely the community committee, committee of sub-district and academic persons. The experimental results obtained from four rural villages show that weighted important value of sustainable development indicators are 0.5963, 0.2546 and 0.1491 for the social, economy and environment indicators, respectively. In order to consider on the indicators for communities quality of life of those SHS installation households in remote areas, this result will be applied to design both the questionnaire and constraints in optimization technique for the further research

    Comparison of CO2 Emissions from Vehicles in Thailand

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    Emission of carbon dioxide (CO2), a greenhouse gas, from typical passenger vehicles in Thailand was investigated using a chassis dynamometer in the Automotive Emission Laboratory. The vehicle running method was controlled under the standard Bangkok driving cycle. CO2 emissions were measured at three different speeds for the following four vehicle types commonly used in Thailand: heavy duty diesel (HDD), light duty diesel (LDD), and light duty gasoline (LDG) vehicles and motorcycles (MC). HDD vehicles had the highest average CO2 emission rate, followed by LDD, LDG and MC at 1,198.8±93.1, 268.4±21.3, 166.1±27.7 and 42.5±6.1 g km-1, respectively; all values were significantly different (p < 0.05) from each other. The effect of different fuel types, including diesel, gasoline 91, gasohol 95, gasohol 91, liquid petroleum gas (LPG) and natural gas for vehicles (NGV), on the CO2 emission level was also compared. HDD vehicles had a higher rate of CO2 emission when using either NGV or diesel, while LDD vehicles emitted more CO2 with diesel than with NGV. For LDG vehicles, more CO2 was emitted with gasohol 91 than with gasohol E20, LPG or NGV. Finally, MC had a higher average CO2 emission rate with gasohol 95 than with gasoline 91 and gasohol 91 at any vehicle speed. The CO2 emission rates obtained in this study can be used as a basis to create a database that supports development of an efficient transportation management system and reduced vehicular emission of greenhouse gases in Thailand

    Ozone Formation Potential of Ambient Volatile Organic Compounds at Roadside in Bangkok, Thailand

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    Volatile organic compounds (VOCs) play an important role in atmospheric chemistry due to their high reactivity—reacting photochemically with oxides of nitrogen (NOx) in the presence of solar radiation forming tropospheric ozone (O3). Each VOC species have different effects on ozone formation according to the rates and pathways of their reactions. The objective of this study aims to examine ozone formation from the estimation of ozone formation potential (OFP). The observation of 29 VOCs species was carried out in the urban area near the roads of Bangkok, Thailand. Measurements were carried out during the dry season, from 16th February to 15th March, 2018. The air samples were analyzed using gas chromatography flame ionization detector (GC-FID). The results showed that toluene had the highest VOCs concentration followed by propane, and carbon tetrachloride (CCl4). The average ratio of benzene to toluene (B/T) and toluene to benzene (T/B) indicate that both toluene and benzene emitted from industrial area and vehicular emission. Ratio of m/p-xylene to benzene (m/p-X/B) indicate that BTEX emitted far from the source. The ozone formation potential indicated that toluene was the main VOC contributing to the total ozone formation. High VOCs concentration in monitoring site was influenced by vehicular sources and the sea breeze brought the pollutants back to the land

    Enhancing High-concentrated Wastewater Quality on Evaporation Rate from Five-Consecutive Oxidation Ponds as Located in Phetchaburi, Southerly Thailand

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    This research aimed to examine the environmental factors determining the rates of evaporation, a natural phenomenon contributing to the treatment of wastewater of 5-consecutive oxidation ponds of the King’s Royally Initiated Laem Phak Bia Environmental Research and Development Project. Data collected from the 17th of April to 30th of May 2019 by US Class A Evaporation Pan revealed that the sedimentation pond (Pond 1) has the highest rate, 7.22 mm d-1, the oxidation pond 1 (Pond 2), 5.70 mm d-1, the oxidation pond 3 (Pond 4), 5.56 mm d-1, the stabilization pond (Pond 5), mm d-1, the reference pond at 5.07 mm d-1 and the oxidation pond 2 (Pond 3), 3.59 mm d-1. Concluding the evaporation in domestic wastewater treatment plants is characterized by 1) heat generated from short and long wave radiation emitted by earth and the sun, 2) local wind profiles of the area affected the height differences of the roughness length, and 3) heat generated by the respiration and digestion process of microbial activities and other grey body contaminants. Presenting the day and night variations made for the analysis, the day evaporation was significantly higher resulted by the net radiation were accountable. Wind profile generated from the measurement of speeds and directions at two different sites at 3 and 10 m has explained for the roughness length heights over each pond as lower roughness height have cause the increased in the rates of evaporation in Pond 4 and 5 however, these processes were also suppressed by high ionic bonding molecules effected suggested by the high TDS and EC values. The vertical temperature profile has conveyed the movement in the heat flux that dominated an upward flux movement in Pond 1. This is the exothermic reaction from the digestion process have suggested that extra heat has been added

    The history of leishmaniasis

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    In this review article the history of leishmaniasis is discussed regarding the origin of the genus Leishmania in the Mesozoic era and its subsequent geographical distribution, initial evidence of the disease in ancient times, first accounts of the infection in the Middle Ages, and the discovery of Leishmania parasites as causative agents of leishmaniasis in modern times. With respect to the origin and dispersal of Leishmania parasites, the three currently debated hypotheses (Palaearctic, Neotropical and supercontinental origin, respectively) are presented. Ancient documents and paleoparasitological data indicate that leishmaniasis was already widespread in antiquity. Identification of Leishmania parasites as etiological agents and sand flies as the transmission vectors of leishmaniasis started at the beginning of the 20th century and the discovery of new Leishmania and sand fly species continued well into the 21st century. Lately, the Syrian civil war and refugee crises have shown that leishmaniasis epidemics can happen any time in conflict areas and neighbouring regions where the disease was previously endemic

    A historical overview of the classification, evolution, and dispersion of Leishmania parasites and sandflies

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    Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites

    Carbon dioxide and methane emission rates from taxi vehicles in Thailand

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    Due to the expansion of urban areas have been increasing levels of greenhouse gas emissions from taxi and passenger cars that use natural gas for vehicles (NGV) and liquid petroleum gas (LPG) as alternative fuels . The objective of this study was to evaluate the CO2 and CH4 emission of NGV and LPG taxis with different times from their engine ages compared to those from passenger cars. The driving tests were conducted at three driving speed ranges in Bangkok, Thailand. No significant differences in the CO2 emission rates from taxis and passenger cars using either NGV or LPG (174.5–227.0 g/km) were found. However, NGV taxis emitted the highest CH4 at all driving speeds, with an average emission of 1.33 g/km, higher than that from the LPG taxis. Comparing between taxis and passenger cars, the NGV taxis emitted the highest of CO2 and CH4 (13.8 ton CO2-eq/y), followed by LPG taxis (12.5 ton CO2-eq/y). The results obtained in this study can be used to create a database that supports the decision-making on development projects and to control GHG emission in Thailand

    Vertical Variation of Nitrogen Oxide (NOx) Concentration Using a Backward Air Mass Trajectories Model in an Urban Area of Bangkok, Thailand

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    Bangkok Metropolitan is a rapidly growing city with both industrial and urban area expansion resulting in the generation of a significant air pollutant; Nitrogen Oxide (NOx = NO + NO2). This research studied the variation of Nitrogen Oxide concentration in an urban area at 30 m and 110 m above ground by applying the HYSPLIT model to simulate the backward trajectories movement of air mass using the past 3 days of data from an air quality and microclimate monitoring station at Kasetsart University, Bangkok from January 2016 to February 2017. The results showed that the concentration of Nitrogen Oxide at 30 m above ground is higher than the concentration at 110 m above ground. The concentration trended to increase in winter (October 2016 to February 2017). According to the backward trajectories modeling, the major direction of air mass movement at 30 m above ground, category 1 (N-NE) and category 2 (NE-E), occupying 86% of total movement direction (concentration of NOx ranged from 4.02 to 96.35 ppb) meanwhile the major direction of air mass movement at 110 m above ground, category 1 (N-NE) and category 2 (NE-E), occupying 79% of total movement direction (concentration of NOx ranged from 3.93 to 51.50 ppb). The air mass moved through the different land use types, human activities and industrial areas. This study can be applied as a guideline for microclimate surveillance and monitoring of NOx concentration influenced by air mass movement
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