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Publication Open Access 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 EngineeringPopulation 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.Publication Open Access 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 EngineeringInterest 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.Publication Open Access 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 EngineeringThis 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.Publication Open Access 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 EngineeringOver 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.Publication Open Access 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 TechnologyOffshore 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 motionPublication Open Access 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 CenterEmpirical 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.Publication Metadata only 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. LtdThis 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 RAMPIPEguidelinesPublication Open Access 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., LtdSteel 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.Publication Open Access องค์ประกอบของของเสียจากการก่อสร้างและรื้อถอนจากสถานที่กองเก็บ(2008-06) ธัชวีร์ ลีละวัฒน์; อัจฉรา อัศวรุจิกุลชัย; อุษณีย์ อุยะเสถียร; มหาวิทยาลัยมหิดล. คณะวิศวกรรมศาสตร์; มหาวิทยาลัยมหิดล. คณะสิ่งแวดล้อมและทรัพยากรศาสตร์งานวิจัยนี้ได้ทำการสำรวจและเก็บตัวอย่างของเสียจากการก่อสร้างและรื้อถอนจากสถานที่กองเก็บจำนวน 6 แห่งในพื้นที่เขตกรุงเทพฯและปริมณฑล เพื่อทำการศึกษาถึงองค์ประกอบของเสียจากการก่อสร้างและรื้อถอน เพื่อให้ได้แนวโน้มการนำของเสียจากการก่อสร้างและรื้อถอนกลับไปใช้เป็นวัสดุมวลรวมทดแทน จากการศึกษา พบว่าองค์ประกอบของของเสียจากการก่อสร้างและรื้อถอนจากแต่ละสถานที่กองเก็บมีความแตกต่างกัน ค่อนข้างมาก องค์ประกอบหลักส่วนใหญ่ของของเสียประเภทนี้ประกอบด้วยคอนกรีตและมอร์ต้าร์ ซึ่งมีปริมาณ มากเกินกว่าร้อยละ 62 ยกเว้นของเสียที่ได้มาจากงานรื้อถอนถนนซึ่งมีองค์ประกอบหลักคือแอสฟัลต์ โดยทั่วไป พบว่าของเสียจากการก่อสร้างและรื้อถอนจากสถานที่กองเก็บส่วนใหญ่จัดอยู่ในประเภทของเสียผสมPublication Open Access 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 EngineeringIn 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.Publication Metadata only Impact of undesirable outputs on the productivity of US airports(2008) Somchai Pathomsiri; Haghani, Ali; Dresner, Martin; Windle, Robert J.; Mahidol University. Faculty of Engineering. Department of Civil EngineeringThe paper assesses productivity of 56 US airports during the period 2000–2003. Unlike past work, this study models joint production of both desirable and undesirable outputs (i.e., delays) using the non-parametric directional output distance function. Results are compared to those from models that do not include undesirable outputs. The results show that if delayed flights are excluded from the model, many large but congested airports are found to be efficient. After accounting for delays, small, less congested airports are also found on the efficient frontier. Finally, the model is also used to analyze the effects of other variables.Publication Metadata only ผลของข้อมูลข่าวสารต่อทัศนคติและพฤติกรรมการใช้รถยนต์ส่วนตัว(2547) สมชาย ปฐมศิริ; ไชยรัตน์ หวังพัฒนะวงศ์; ประวีณ สุวรรณภักดี; มหาวิทยาลัยมหิดล. คณะวิศวกรรมศาสตร์Publication Metadata only Limitations of DEA-based approach and alternative methods in the measurement and comparison of social efficiency across firms in different transport modes: An empirical study in Japan(2013) Oum, Tae Hoon; Somchai Pathomsiri; Yoshida, Yuichiro; Mahidol University. Faculty of Engineering. Department of Civil EngineeringThis paper measures and compares social efficiency of railway firms and airlines in Japan’s domestic intercity travel market. Unlike other efficiency studies, our input and output measures are more comprehensive because we incorporate the life-cycle CO2 emissions as an undesirable output and travelers’ time and government spending on air infrastructure as inputs. We use the nonparametric directional output distance function (DODF) together with the composite social efficiency index to analyze the yearly panel data of the three major railroads and two major airlines during 1999–2007. The results indicate that the railroads are more socially efficient than airlines. Furthermore, we discuss the inability of nonparametric DODF method for comparing the social efficiency of firms across modes.Publication Metadata only "MU Library" บริการโปรแกรมระบบห้องสมุดอัตโนมัติแห่งมหาวิทยาลัยมหิดล เพื่อคนไทย(2555) ชนัฏฐา ทองสุข; วีรนี ทองเขาอ่อน; มหาวิทยาลัยมหิดล. คณะวิศวกรรมศาสตร์. สาขาวิชาเทคโนโลยีการจัดการระบบสารสนเทศ; มหาวิทยาลัยมหิดล. คณะวิศวกรรมศาสตร์. ศูนย์บริหารการจัดการองค์กรสากลPublication Open Access Short- and Long-term Performance of Fibre-Reinforced Cement Profile Sheets Containing Asbestos and Non-asbestos Materials(2012-12) ธัชวีร์ ลีละวัฒน์; Thatchavee Leelawat; Mahidol University. Faculty of Engineering. Department of Civil and Environmental EngineeringThe paper was aimed at comparing the performance of roof products in asbestos- and non-asbestos-reinforced cement profile sheets. Four brands of cement tiles were blinded and then sent for investigation. They were classified as blue, brown, red and green tiles. The physical and chemical tests were conducted to distinguish the properties of these tiles. The short-term properties of cement tiles were determined by breaking load per metre width. Whereas the impermeability, warm water, and heatrain tests were conducted for the determination of long-term properties for all types of cement tiles. The results undertaken have shown that blue and brown tiles had similar types of fibres which were shorter than those fibres of red and green tiles. The bending results of blue and brown tiles were significantly higher than those red and green tiles. However, the blue tiles exhibited the worst impermeability results due to their imperfection of coating. Whereas the test conditioning the tiles in warm water was found that only green tiles could not meet with the requirement of ISO 9933 standard. The heat-rain test for all of the tiles being investigated was found to meet with the standard criterion.Publication Open Access Factors affecting near surface tests of in-situ concrete structures for carbonation-induced corrosion.(2013-06) Chatchai Manathamsombat; Praveen Chompreda; Thatchavee Leelawat; Mahidol University. Faculty of EngineeringCorrosion in RC members leads to reduction in strength and serviceability of the structures. Several non-destructive testing techniques can be employed to evaluate the possibility of reinforcement corrosion relatively quickly and cost-effectively. However, due to uncontrollable variations of structures conditions in the field, the reliability and validity of the test results are in doubt. This paper examines the effects of surface conditions, concrete moisture content, ambient conditions, and carbonation depth on the rebound number, half-cell potential, two and four-probe resistivities, and linear polarization resistance. Eighteen reinforced concrete buildings located in Bangkok metropolitan areas which are ten years or older were sampled. Statistical analyses were performed to determine the significance of each effect on the non-destructive test values. The effects and relationship of each factor were shown on this paper.Publication Metadata only Prediction of bond dissociation enthalpy of antioxidant phenols by support vector machine(2008) Chanin Nantasenamat; Chartchalerm Isarankura-Na-Ayudhya; Thanakorn Naenna; Virapong Prachayasittikul; Mahidol University. Faculty of Engineering. Department of Industrial Engineering; Mahidol University. Faculty of Medical Technology. Department of Clinical MicrobiologyAntioxidants play crucial roles in scavenging oxidative damages arising from reactive oxygen species. Bond dissociation enthalpy (BDE) of phenolic O–H bond has well been accepted as an indicator of antioxidant activity since phenols donate the hydrogen atom to the free radicals thereby neutralizing its toxic effect. The BDEs from a data set of 39 antioxidant phenols were modeled using computationally inexpensive quantum chemical descriptors with multiple linear regression (MLR), partial least squares (PLS), and support vector machine (SVM). The molecular descriptors of the phenols were derived from calculations at the following theoretical levels: AM1, HF/3-21g(d), B3LYP/3-21g(d), and B3LYP/6-31g(d). Results indicated that when MLR and PLS were used as the regression methods, B3LYP/3-21g(d) gave the best performance with leave-one-out cross-validated correlation coefficients (r) of 0.917 and 0.921, respectively, while the semiempirical AM1 provided slightly lower r of 0.897 and 0.888, respectively. When SVM was used as the regression method no significant difference in the accuracy was observed for models using B3LYP/3-21g(d) and AM1 as indicated by r of 0.968 and 0.966, respectively. The quantitative structure–property relationship (QSPR) model of BDE discussed in this study offers great potential for the design of novel antioxidant phenols with robust properties.Publication Metadata only Identification of ischemic heart disease via machine learning analysis on magnetocardiograms(2008-06) Tanawut Tantimongcolwat; Thanakorn Naenna; Chartchalerm Isarankura-Na-Ayudhya; Embrechts, Mark J.; Virapong Prachayasittikul; Mahidol University. Faculty of Engineering. Department of Industrial EngineeringIschemic heart disease (IHD) is predominantly the leading cause of death worldwide. Early detection of IHD may effectively prevent severity and reduce mortality rate. Recently, magnetocardiography (MCG) has been developed for the detection of heart malfunction. Although MCG is capable of monitoring the abnormal patterns of magnetic field as emitted by physiologically defective heart, data interpretation is time-consuming and requires highly trained professional. Hence, we propose an automatic method for the interpretation of IHD pattern of MCG recordings using machine learning approaches. Two types of machine learning techniques, namely back-propagation neural network (BNN) and direct kernel self-organizing map (DK-SOM), were applied to explore the IHD pattern recorded by MCG. Data sets were obtained by sequential measurement of magnetic field emitted by cardiac muscle of 125 individuals. Data were divided into training set and testing set of 74 cases and 51 cases, respectively. Predictive performance was obtained by both machine learning approaches. The BNN exhibited sensitivity of 89.7%, specificity of 54.5% and accuracy of 74.5%, while the DK-SOM provided relatively higher prediction performance with a sensitivity, specificity and accuracy of 86.2%, 72.7% and 80.4%, respectively. This finding suggests a high potential of applying machine learning approaches for high-throughput detection of IHD from MCG dataPublication Metadata only Design and development of system integration for fluoroscopic navigation using surgical-guiding robot(2011) Sakol Nakdhamabhorn; Jackrit Suthakorn; Mahidol university. Faculty of Engineering. Department of Biomedical EngineeringFluoroscopic x-ray is an essential tool for orthopedic surgery, especially, Close Intramedullary Nailing Operation. Close intramedullary nailing is a very efficiency technique for treatment the long bone fracture. In this technique, surgeon is required to insert an intramedullary nail into the medullary canal to stabilize the fractured bone. The most difficult task for the surgeon is to identify two screwing holes at the distal location of the nail. In conventional method, surgeon requires a lot of fluoroscopic exposures to recover distal interlocking holes. Therefore, both of surgeon and patient continually absorb an irradiation that is harmful for their long term health. This paper presents a system for fluoroscopic navigation in close intramedullary nailing. The systems are integrated with three sub-systems: 1) A recovery of distal interlocking holes system for locating distal interlocking holes. 2) An optical tracking system for registering an x-ray image coordinate into the world coordinate. 3) A surgical guiding robot system for guiding a position and orientation of distal interlocking holes using robot guidance.Publication Metadata only Development of a novel robotic monofilament probe for diabetic neuropathy screening(2009-12-15) Yuttana Itsarachaiyot; Jackrit Suthakorn; Wirawat Sirisopha; Chumpon Wilasrusmee; Mahidol University. Faculty of EngineeringPeople with diabetes are unable to produce or properly consume insulin, which is produced by pancreas. A common complication of diabetes is diabetic neuropathy which is able to affect any part of the nervous system. The diabetic peripheral neuropathy is normally detected by the physicians during the patient’s examination. The physician detects the loss of sensations in diabetic foot by using a monofilament to apply onto 3 sites on each foot. This study is to introduce a new robotic monofilament probe for diabetic neuropathy screening as a section of a telemedicine for diabetes disease project. The development of the “Robotic Monofilament Probe” is able to reduce the cost and time for both patient and physician during the long term examination period. Moreover, the system is a part of telemedicine project for diabetes disease which the system will be able to transfer examination data to the physician in a remote area.