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    Investigation on Impact of Changes in Land Cover Patterns on Surface Runoff in Ayung Watershed, Bali, Indonesia Using Geographic Information System
    (2022) Dharmayasa, I Gusti Ngurah Putu; Kritsanat Surakit; Jindal, Ranjna; Romanee Thongdara; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering
    Population growth, urbanization, and infrastructure development activities have resulted in the land conversion of forests and farmlands to residential and commercial zones. Such land conversion causes changes in the land cover, as experienced in the Ayung Watershed, in the island of Bali, Indonesia. Here, the land cover undergoes rapid changes due to the growing tourism sector, affecting the runoff coefficient. This study evaluated the changing land cover patterns and surface runoff in the Ayung Watershed between 2012 and 2019. An increase in the surface runoff during the high rainfall events may lead to flooding in the area. The identification of land change patterns in the Ayung Watershed was carried out by a manual digitizing process on Google Earth maps. The runoff coefficient was calculated by Cook’s method using the four physical characteristics of the watershed: land cover, infiltration rate, land slope and drainage density; showing significant changes in the land cover in the study area. Farmlands and forests were reduced by 647.8 ha and 553.1 ha respectively, converted into fast growing grasslands or unproductive land. Such land cover changes have a negative impact by increasing the runoff coefficient in the area. During the study period, the runoff coefficient was consistently found to be more than 0.6 (high-risk category). Several sections in the city of Denpasar experienced an increase in the runoff coefficient by more than 5%. Consequently, there was a high-risk of flooding in the area because of the increasing surface runoff.
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    Biosynthesis of Silver Nanoparticles Using Orange Peel Extract for Application in Catalytic Degradation of Methylene Blue Dye
    (2021) Cathleen Simatupang; Vinod K Jindal; Ranjna Jindal; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Mahidol University. Faculty of Engineering. Department of Chemical Engineering
    Interest in the biosynthesis of silver nanoparticles (AgNPs) has been steadily increasing primarily due to their numerous applications in various fields, low-cost, use of non-toxic environmentally-friendly materials and easy implementation. This study focused on the biosynthesis of AgNPs using orange peel extract (OPE), optimization of process conditions, and application in catalytic degradation of methylene blue (MB) dye used in the textile industry. A central composite design in response surface methodology resulted in optimum conditions of 0.0075 g dry peel/mL for OPE concentration, pH of 11 and 1.5 mM silver nitrate concentration. The optimum conditions for the response variables corresponded to the peak absorbance of 0.79 and SPR wavelength of 403.8 nm in UV-vis spectra, and minimum particle size of 12.9 nm. In addition, peak absorbance and SPR wavelength appeared to be related to the size of the AgNPs. A full-factorial design for the catalytic degradation of MB dye by the biosynthesized AgNPs for 1 h indicated the maximum influence of AgNPs compared to the concentrations of MB dye and NaBH4 in decreasing order. The MB dye was reduced rapidly with NaBH4 in the presence of AgNPs due to their catalytic action. The findings of the study show the potential of OPE for the biosynthesis of AgNPs with excellent catalytic activity for the treatment of MB dye in industrial effluent.
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    Acid-Catalyzed Esterification Pretreatment of High Free Fatty Acid Crude Rice Bran Oil for Biodiesel Production
    (2019) Tin Mar Lar Thein; Jindal, Vinod K.; Ranjna Jindal; NuttawanYoswathana; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Mahidol University. Faculty of Engineering. Department of Chemical Engineering
    This study investigated the acid-catalyzed esterification of two brands of crude rice bran oil (CRBO) with free fatty acids (FFAs) content of about 8 and 10%, respectively. Experimental variables included reaction time, methanol-to-FFA molar ratio and sulfuric acid content with temperature and stirring speed fixed at 60 °C and 600 RPM, respectively. A central composite design was used initially for sequential experimentation and followed by a Box-Behnken design to refine the optimum process conditions. Results showed that final FFA in CRBO could be reduced to less than 1% FFA in a single-step. The methanol-to-FFA molar ratio had the maximum influence on the esterification process and was followed by the reaction time and amount of catalyst. The optimum conditions for FFA conversion in CRBO were: reaction time 90 and 48 min, 62:1 and 70:1 methanol-to-FFA molar ratio, 22.5 and 20% (w/w) sulfuric acid based on FFA for Brand I and II, respectively. Under these pretreatment conditions, initial FFA was reduced to 0.61 and 0.70%, respectively making the CRBO suitable for biodiesel production.
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    Seismic damage to ancient monuments in Chiang Saen (Northern Thailand): Implication for historical earthquakes in Golden Triangle area
    (2019) Teraphan Ornthammarath; Mahidol University. Faculty of Engineering. Department of Civil Engineering
    Over the last few decades, three moderate earthquakes (Mw greater than 6.0) occurred in and around the Golden Triangle area (including Myanmar, Thailand and Lao PDR) causing unprecedented damage and loss of lives in the epicentral region. In addition to the damage to modern structures, most heritage structures in Chiang Saen, a major city of the Lan Na kingdom (from the thirteenth to the eighteenth century), were also affected. This work is intended to present observed historical structure damage from recent earthquakes, which could provide evidence for the severity of historical earthquakes from the thirteenth to the eighteenth century. Based on historical records, geological evidence and observed damage to ancient monuments in this historic town, existing heritage stupas and temples constructed since the fourteenth century sustained only minor to moderate damage from these historical earthquakes. Considering the seismic vulnerability of these historical monuments, Chiang Saen might have never been subjected to severe ground shaking greater than MMI intensity VII, similar to the major earthquake in 460 A.D. along the Mae Chan fault, which was responsible for the large-scale liquefaction and inundation of ancient Yonok town. This information could be important for paleoseismological and historical earthquake research to constrain the recurrence interval of major active faults in this area.
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    A novel hybridized metaheuristic technique inenhancing the diagnosis of cross-sectional dentdamaged offshore platform members
    (2019) Wonsiri Punurai; M.S. Azad; Nantiwat Pholdee; Sujin Bureerat; Chana Sinsabvarodom; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Khon Kaen University. Faculty of Engineering. Sustainable and Infrastructure Research and Development Center; Norwegian University of Science and Technology. Faculty of Engineering. Department of Marine Technology
    Offshore jacket platforms are widely used for oil and gas extraction as well as transportation in shallow to moderate water depth. Tubular cross-sectional elements are used to construct offshore platforms. Tubular cross-sections impart higher resistance against hydrodynamic forces and have high torsional rigidity. During operation, the members can be partially or fully damaged due to lateral impacts. The lateral impacts can be due to ship collisions or through the impact of falling objects. The impact forces can weaken some members that influence the overall performance of the platform. This demonstrates an urgent need to develop a framework that can accurately forecast dent depth as well as dent angle of the affected members. This study investigates the use of an adaptive metaheuristics algorithm to provide automatic detection of denting damage in an offshore structure. The damage information includes dent depth and the dent angle. A model is developed in combination with the percentage of the dent depth of the damaged member and is used to assess the performance of the method. It demonstrates that small changes in stiffness of individual damaged bracing members are detectable from measurements of global structural motion
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    Empirical seismic fragility functions based on field survey data after the 5 May 2014 Mae Lao (Northern Thailand) earthquake
    (2019) Piyawat Foytong; Teraphan Ornthammarath; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Khon Kaen University. Faculty of Engineering. Department of Civil Engineering. Sustainable Infrastructure Research and Development Center
    Empirical seismic fragility curves have been developed based on post-seismic survey data on official building damage, collected in the epicentral area of Mw 6.1, 2014 Mae Lao earthquake. In total, about 26,551 survey building data have been investigated by authorities and engineers. The typical pattern of observed damage for different structures and the reasons for damage are presented. In addition, damage statistics in the field are correlated with ground motion in order to derive empirical seismic fragility curves. Using a maximum likelihood method, different sets of fragility curves are developed to demonstrate the influence of structural material on building damage level. The good correlation between observed damage and peak ground acceleration (PGA) are observed. In addition, the results show a better seismic performance of the engineered reinforced concrete building over non-engineered buildings. These findings are essential to support a better future building damage assessments, land use management, and seismic risk mitigation planning.
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    Effects of Redundancy in Bracing Systems on the Fragility Curve Development of Steel Jacket Offshore Platform
    (2019) M.S. Azad; Wonsiri Punurai; Chana Sinsabvarodom; Pornpong Asavadorndeja; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Norwegian University of Science and Technology. Department of Marine Technology; Synterra Co., Ltd
    Steel jacket offshore platforms are typically employed for use in shallow to moderate water depths. During platform operations, there have been some historical accidents completely damaging the diagonal members of the bracing systems due to explosions, fire accidents and dropped objects. Different locations of damaged bracings demonstrate different levels of risk for safety and integrity of the structures. This research illustrates the effects of redundancy in the bracing systems for steel jacket offshore platforms. Assessments have been carried out using the nonlinear pushover analysis method and formations of nonlinear hinges of different members were noted. Redundancy in different positions has been considered to investigate the consequences. Reserve strength ratio (RSR) and damage strength ratio (DSR) of the global structure were also evaluated to understand the importance of different local members. From the collapse data of local failures, fragility curves for the global structures were estimated. The results demonstrated that the position of damage can be a great concern which affects the overall performance of the structures.
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    Reliability assessment of thick high strength pipelines with corrosion defects
    (2019) U. Bhardwaj; A.P. Teixeira; C. Guedes Soares; Md Samdani Azad; W. Punurai; P. Asavadorndeja; Universidade de Lisboa. Instituto Superior Técnico, Universidade de Lisboa. Centre for Marine Technology and Ocean Engineering (CENTEC); Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering; Synterra Co. Ltd
    This paper assesses the reliability of thick, high strength corroded pipelines subjected to internal pressure by firstorder reliability algorithms and Monte Carlo simulation methods. First, the predictions of different burst strengthmodels, including a new prediction model for thick high strength pipelines are compared with experimentalresults. Model uncertainty factors are derived for intact and corroded pipelines to calibrate and introduce theuncertainties on the models used in the prediction of structural reliability. The uncertainty associated withmodel uncertainty factors is addressed and the best fitting distribution is identified. Extensive reliability andsensitivity analyses are carried out on intact and corroded pipes with calibrated burst strength models. Throughsensitivity analyses performed for increasing levels of corrosion defects, the influence of basic parameters on theburst strength of corroded pipelines is characterized. The results demonstrate that the model uncertainty factorsand the depth of corrosion are relatively important variables for corroded pipelines. The results obtainedthrough reliability assessment are compared with that obtained by the strength model proposed in the RAMPIPEguidelines
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    องค์ประกอบของของเสียจากการก่อสร้างและรื้อถอนจากสถานที่กองเก็บ
    (2008-06) ธัชวีร์ ลีละวัฒน์; อัจฉรา อัศวรุจิกุลชัย; อุษณีย์ อุยะเสถียร; มหาวิทยาลัยมหิดล. คณะวิศวกรรมศาสตร์; มหาวิทยาลัยมหิดล. คณะสิ่งแวดล้อมและทรัพยากรศาสตร์
    งานวิจัยนี้ได้ทำการสำรวจและเก็บตัวอย่างของเสียจากการก่อสร้างและรื้อถอนจากสถานที่กองเก็บจำนวน 6 แห่งในพื้นที่เขตกรุงเทพฯและปริมณฑล เพื่อทำการศึกษาถึงองค์ประกอบของเสียจากการก่อสร้างและรื้อถอน เพื่อให้ได้แนวโน้มการนำของเสียจากการก่อสร้างและรื้อถอนกลับไปใช้เป็นวัสดุมวลรวมทดแทน จากการศึกษา พบว่าองค์ประกอบของของเสียจากการก่อสร้างและรื้อถอนจากแต่ละสถานที่กองเก็บมีความแตกต่างกัน ค่อนข้างมาก องค์ประกอบหลักส่วนใหญ่ของของเสียประเภทนี้ประกอบด้วยคอนกรีตและมอร์ต้าร์ ซึ่งมีปริมาณ มากเกินกว่าร้อยละ 62 ยกเว้นของเสียที่ได้มาจากงานรื้อถอนถนนซึ่งมีองค์ประกอบหลักคือแอสฟัลต์ โดยทั่วไป พบว่าของเสียจากการก่อสร้างและรื้อถอนจากสถานที่กองเก็บส่วนใหญ่จัดอยู่ในประเภทของเสียผสม
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    Framework for LCI modelling towards green logistic systems
    (2012-12) Trakarn Prapaspongsa; Løkke, Søren; Trakarn Prapaspongsa; Mahidol University. Faculty of Engineering. Department of Civil and Environmental Engineering
    In order to establish green logistic systems, life cycle assessment (LCA) is an important tool for evaluating and comparing overall environmental impacts from various options. Most LCA studies rely on readily available secondary databases on transport services such as Ecoinvent database and scientific publications. The most widely applied Ecoinvent database on transport services is aggregated with specific transport variables and statistics based on European and Swiss average data. To modify the life cycle inventory (LCI) database with specific variables (e.g. load factors, driving speed, etc.) is very complicated and may not be possible. Such studies are still lacking due to complexity and resource limitations. This study aims to provide a framework for LCI modelling to conduct LCAs of European freight transport with up-to-date LCI data in terms of emissions and transport variables. The framework comprises of a conceptual transport model, important transport variables and data sources for freight transport by road and by rail in Europe. The data collection was carried out by literature studies and interviews with relevant experts. The framework is useful for LCA practitioners, researchers and industries to include specific transport variables and to adequately assess the environmental impacts from transport activities by road and by rail.