Engineering Journal (Faculty of Engineering, Chulalongkorn University, Bangkok)
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Evaluation of Effect of Median U-Turns on Multilane Primary Highway Capacity in Thailand through Traffic Micro-Simulation Models
Get PDFThis article aims to analyze the effect of median U-turns and estimate the capacity of primary highways in Thailand using a traffic micro-simulation model. Six-lane and four-lane primary highways were selected for the study. The base condition results determined that the maximum capacity of a six-lane primary highway was 2,130 passenger cars/hour/lane, while the four-lane primary highway capacity was recorded as 2,194 passenger cars/hour/lane. Both results were slightly higher than those of the HCM2010 approach. Under prevailing conditions, both sections exhibited lower capacities than the HCM results by approximately 33.7% and 19.8% for the six-lane and four-lane primary highways, respectively, causing the impact of the median U-turn and highway characteristics in Thailand to directly affect traffic and driving behavior. Using the micro-simulation results, an equation was also regressed for estimating the capacity resulting from the impact of the median U-turns and heavy vehicles. These results may be used as guidelines for the design and analysis of multilane highways in Thailand
Important Role of Abiotic Sulfide Oxidation in Microbial Fuel Cells Treating High-Sulfate Wastewater
Get PDFMicrobial fuel cells (MFCs) have been considered as an alternative for the treatment and energy recovery of organic wastewater containing sulfate, which cannot be achieved via conventional anaerobic treatment processes. This study investigates the performances and mechanisms of two-compartment single-chamber MFCs treating sulfate-rich organic wastewater at the chemical oxygen demand (COD) to sulfate ratio of 1, 3, and 6 in MFC1, MFC3, and MFC6, respectively. The first compartments functioned as anaerobic bioreactors. In the second compartments where fuel cell apparatuses were installed, sulfide removal was 49.51 ± 57.74, 24.08 ± 13.74, and 15.69 ± 21.30 mgS2-/L in MFC1, MFC3, and MFC6, respectively. The maximum power generation amounts of 9.33, 1.79, and 1.41 mW/m2 were achieved in MFC1, MFC3, and MFC6, respectively. A higher sulfide concentration in MFC1 contributed to higher power generation in MFC1. The main mechanism of electrical generation in all MFCs was abiotic sulfide oxidation
Urban Growth Prediction of Special Economic Development Zone in Mae Sot District, Thailand
Get PDFSince the ASEAN Economic Community (AEC) was activated in 2015, eight subdistricts of Mae Sot district in Tak province, Thailand have been regarded as special economic development zones (SEZ) due to their situation on the border of Thailand near the pathway of the East-West Economic Corridor project (EWEC). Thus, the Thai Government is developing many infrastructure projects there, and the urban areas are likely to expand, as the population is increasing dramatically. The study of land use could aid in more efficient decision-making in urban planning, and could mitigate the effects of uncontrolled urban development. Based on this background, land use change monitoring was performed based on Remote Sensing and Geographic Information System (GIS) using high-resolution satellite images. The images were captured by QuickBird in 2006, and by Thaichote in 2011 and 2016. The object-based classification considers not only the reflectance of the pixels but also the size, shape, color, smoothness, and compactness of the objects. This technique will bring higher accuracy to land use classification. The eCognition Developer was employed in this study for object-based classification. The mean and standard deviation of the original band was used for principle component analysis (PCA), and the normalized difference vegetation index (NDVI) was also applied to land use classification. The types of land use were divided into five categories that followed the definitions given by the Land Development Department of Thailand (LDD): agricultural area, forest, urban area, water body, and miscellaneous land. The results of land use classification showed that urban areas increased drastically year by year. The GIS dataset for land use compiled by the LDD was employed to evaluate the accuracy of our results. The overall accuracies based on the images captured in 2006 and 2011 were 86.00% and 79.88%, respectively. To evaluate urban growth in 2015, the states of land use in 2006 and 2011 were applied to a Markov Chain and Cellular Automata model (CA-Markov), which is a model for the prediction of land use change from one period to another. The Markov model evaluates the transition probability matrix to project future change, while CA-Markov performs the spatial variations in cell time transition and neighborhood based on its element cell space, cell states, time steps, transition rules, and neighbors. The accuracy of the land use prediction obtained from CA-Markov in 2016 was evaluated by comparing it with land use classification from the object-based classification of the image captured by Thaichote in 2016. The overall accuracy was 68.45%. The pattern of land use change detected from both the projection map and the classification map showed that the urban area would spread following the development of transportation infrastructure, and would encroach on the agricultural areas, while forest areas would become agricultural areas
Automatic Transformation of Ordinary Timed Petri Nets into Event-B for Formal Verification
Get PDFThe behavioral correctness of real-time software system relies on both the result of its computation and the clock times when the result is produced. Obviously, formal verification of the safety and correctness of real-time software specification from the very beginning of the software design phase obviously helps us reduce the development efforts. From a practical point of view, the timed Petri net is commonly used to graphically model and illustrate the views of the timed behaviors of the real-time software system. However, the simulation of a timed Petri net is tedious and ineffective for the huge and complex real-time system. Alternatively, formal verification using Event-B specification method provides an efficient automatic theorem proving tool but writing an Event-B specification from scratch is still difficult and needs mathematical logic background. In this paper, we propose an automatic transformation of ordinary timed Petri nets into Event-B specification. The basic notations in the ordinary timed Petri nets are considered and mapped into the code fragments of Event-B. The final resulting Event-B codes are generated in the well-formed format which is required and successfully verified by an Event-B prover called Rodin tool
Upgrading Thai Folk-Designed Rehabilitative Devices for Children with Cerebral Palsy: A Systematic Approach
Get PDFAssistive devices born of indigenous inventiveness possess great potential for systematic refinement through the use of modern design technologies. This paper presents a product development process that began with the selection of suitable folk-designed devices for incorporating into a single new product – an integrated assistive device for children afflicted with cerebral palsy. The process then followed the procedures given by the Sensuous Association Method (SAM) and the Theory of Inventive Problem Solving (TRIZ) to arrive at an optimal design. The finished product incorporates functions for rehabilitating five neuro-motor skills of the afflicted children. After six months of field testing with a sample of nine users, the new product was found to deliver statistically significant benefits to the trial users, i.e. overall strengthening of their gross motor functions. Their sitting skill, in particular, was found to have improved the most
Development of Arbuscular Mycorrhizal Fungi-Organic Fertilizer Pellets Encapsulated with Alginate Film
Get PDFA novel formulation consisting of arbuscular mycorrhizal fungi (AMF) spores mixed with sterilized organic fertilizer (AMF-F) encapsulated by an insoluble calcium alginate film was developed to enhance AMF efficacy and stability. The hardness of the pellets increased from 7–8 N to approximately 80 N by increasing the alginate concentration of the coating film from 1 to 3%. The AMF spore germination rate for the AMF and AMF-F pellets coated with calcium alginate films depended on the alginate concentration. A 2% sodium alginate formulation for the coating films resulted in optimal AMF spore germination rates and mechanical properties for handling, transport, and stability. The inclusion of a sterilized organic fertilizer in the encapsulated AMF-F pellets considerably induced AMF mycelial growth and helped prolong the shelf life of the pellets. In soil, the AMF-F pellets encapsulated with alginate initially degraded faster than the alginate-encapsulated AMF pellets. However, both types of pellets were fully degraded within 30 days. It was demonstrated that AMF and AMF-F could promote colonization and provided resistance to drought stress in maize potted plants
Experimental and Analytical Studies of Door-Type Modular Scaffolds with Initial Geometrical Imperfections
Get PDFIn the study, the performance and structural behaviors of door-type modular steel scaffolds with different degrees of initial geometrical imperfections were evaluated through experimental and analytical investigations. Two one-story and nine two-story modular steel scaffolds were tested to failure. When the number of stories increased from 1 to 2, a 14.8% reduction in load capacity was obtained for the scaffolds with relatively straight columns. The capacity reduction was mainly due to flexibility at column joints and an increase in the deviation from the vertical alignment. The average capacity reductions increased to 18.9% when the out-of-straightness approached the limit provided by the standards. The effective length factors for capacity calculation were determined. In conjunction with the initial imperfections, the results indicated that the flexibility at column joints and the stiffness of beam and sub-frame elements on modular frames significantly affected the failure mode and ultimate load. The beam and sub-frame elements prevented the buckling failure in the modular-frame plane. Hence, the initial imperfections in the plane of cross bracings were more critical than that of the modular-frame plane, and it is necessary to closely inspect the same while using scaffolds in construction
Modelling the Impact of Nigeria Household Energy Policies on Energy Consumption and CO2 Emissions
Get PDFEnergy security, environmental degradation, and climate change have become global topics of discussion. In response to these issues, the federal government of Nigeria has developed the National Renewable Energy and Energy Efficiency Policy (NREEEP). In this policy document, some programs were outlined for the Nigeria household sector. A major initiative in the household energy policies is to incorporate energy efficient appliances in all households by 2030. Here, we use the Long-range Energy Alternatives Planning Systems modelling framework to analyse the effect of these policies on final energy demand and CO2 emissions. The paper also goes ahead to look at the knock-on effects if the policies are sustained up to mid-century. Two scenarios are developed; the reference scenario and the energy policy scenario. Our analysis suggests that if the household energy policies are fully implemented, about 61% reduction in energy demand is achievable by 2030 compared to the reference scenario. The study further indicates that the direct total CO2 emissions will increase by around 2.7 times in the energy policy scenario. If the policies are sustained, the ripple effect indicates that by 2050, total household energy demand will reduce by 58% whereas CO2 emissions will increase by 2.4 times compared with the reference case. Our findings indicate that the current household energy policies are not effective from the perspective of climate change mitigation. Hence, complementary policies are recommended
Flood Modeling Using GIS and PCSWMM
Get PDFModeling flood inundation has become increasingly significant, especially for urban setting. Information on flood characteristics and accurate flow paths is significant for storm water management, hydrological modeling, hydrological data analysis, and vulnerability assessment. This paper employed geographic information system (GIS) to process the input data, RIDF curve to generate different design storm scenarios and PCSWMM to simulate the urban flooding of the Luinab catchment in Iligan City, Philippines. The results demonstrate the methodology for integrating GIS and flood model for analyzing the hydrological behavior of the catchment. The calibrated model clearly identified the area prone to flooding and predicts the influence of imperviousness on the hydrological behavior of the catchment. Improvement of the drainage system could be achieved by a) increasing the capacity of main canal and/or b) providing an additional outlet from identified areas that are prone to flooding
Dependency Types Validation of Precedence Diagram Method Using Ontology
Get PDFPrecedence Diagram Method (PDM) is a visual representation technique that depicts the activities involved in a project. It is a tool for scheduling activities using nodes to represent activities and their connections with arrows to illustrate activity dependencies. During project execution, activities in the project may be considered to change and may lead to inconsistency of dependency types. Consequently, dates and deadlines are missed so these mistakes could prove very costly. Since an ontology describes the relationship between the concepts within a domain. Thus, the ontology could be used to represent knowledge of PDM. This paper proposes PDM Ontology in OWL and rules for inferring the new knowledge from existing PDM and validating PDM using SWRL