Engineering Journal (Faculty of Engineering, Chulalongkorn University, Bangkok)
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The Effect of Cylindrical and Triangular Pillars on Changes in Water Levels at Channel Bends
Get PDFThe water level on the outer side of river bends rises and decreases on the inner side. This research, conducted at the Hydraulics Laboratory of the Engineering Faculty at Tadulako University, sought to analyze the effect of the shape of pillars placed in a U-shaped channel bend (180o) on the water level. The pillars used were either cylindrical or triangular. A U-shaped channel was made from acrylic material with a width of 0.5 meters and radius of 0.75 meters. In order to analyze the effects of pillar shape on the maximum water height, the pillars were moved in increments of 60o and installed simultaneously at bends of 30o, 90o, 150o, and 0o, 60o, 120o. The results show that the cylindrical and triangular pillars affected the water level at the outside of the bend. The maximum height always occurred at bends of 30o. The cylindrical pillar was more economical than the triangular when installing on bridges at bends of 0o or 120o or installed simultaneously at bends of 30o, 90o, 150o. The triangular pillar was more economical when installing on bridges at bends of 60o or 180o or installed simultaneously at the bends of 0o, 60o, 120o
Hazardous Waste Management in the Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University
Get PDFThe aim is to develop landscape garden around the special room, reduce hazardous waste from instruction and research laboratory and manage hazardous waste contaminate of laboratory involves disposal of hazardous waste as required by the policy of Chulalongkorn University, The Center of Excellence on Hazardous Substance Management. In collection process was reduce hazardous waste. In February was the month with the elimination of which has been carried out by containing Mercury Wastewater (IV) in the amount of 180 Liters and solid waste containing Mercury (IV) contaminates at 37.50 kilograms and the removal hazardous waste of 2,718.75 baht. Other types of waste include, Petroleum Product (IX) volume of 25 Liters, wastewater containing Chromate(V) contaminants of 30 Liters, wastewater containing Special Waste (I) of 30 Liters, hazardous wastewater containing Heavy Metal (VI) contaminants of 17.50 Liters and Miscellaneous Aqueous Wastewater (XIV) or hazardous waste with water or solvent dissolve a volume of 15 Liters. In February 2559, the cost of sending hazardous waste was the highest 4,687.50 baht with the volume of 282.50 Liters. The Laboratory of The Department of Environmental Engineering, the cost of sending hazardous waste 6,062.50 baht. Chulalongkorn University operates the storage of hazardous waste by driven plan development, management of chemical and hazardous waste project of The Center of Excellence on Chemical and Hazardous Waste Management is responsible. Finally, hazardous waste management of environmental engineering department under Chulalongkorn University policy by the center of Excellence on Hazardous Substance Management helped save 5,758.08 baht or 94.98% per year
Modeling Frequency of Using Informal Public Transport and Public Bus: A Case Study in Phnom Penh, Cambodia
Get PDFFor decades, informal transport modes such as Motodup and Remork can be commonly observed in the urban area of Phnom Penh. They play an important role as a major public transport for local travelers, even before the public bus was put into full operation in 2014. This study aims to investigate underlying factors that influence the frequency of using informal transport and public bus by considering traveler’s socioeconomic variables, trip characteristics, and operational characteristics of each transport mode. Utilizing ordered probabilistic modeling, data is analyzed based on 483 samples collected from four main areas in Phnom Penh, i.e., CBD, educational, residential and suburb areas. Results indicate that students do not use Motodup frequently, but they would prefer Remork. Moreover, travel cost is seen to be the major factor that could reduce the likelihood of using Motodup and public bus; however, this variable is not found significant in determining the frequency of using Remork. In terms of commuters’ attitudes, Remork and public bus passengers perceive comfort and availability importantly. The more important they value these two factors, the more frequent they would use such modes. Since the public bus is currently a highly promoted public transport, policy makers should incorporate the quality of comfort and availability, and should keep the bus fare low in order to increase the usage frequency
Separation of Lithium Ion from Lithium-Cobalt Mixture using Electrodialysis Monovalent Membrane
Get PDFElectrodialysis is a separation process which ions are transported through semi permeable membranes under an influence of electric potential. In this research, electrodialysis using monovalent ion exchange membranes was applied to separate lithium ions from mixtures of lithium-cobalt aqueous solution. The study aims to examine factors that affect the performances of electrodialysis monovalent membrane, such as applied voltage, flow rate and the concentration of cobalt as co-ion. The research was conducted using electrodialysis PC cell BED 64004, monovalent cation exchange membrane (PC-MVK) and monovalent anion exchange membrane (PC-MVA) produced by PCA-PolymerchemicAltmeier, GmbH, Heusweiler, Germany. The effect of applied voltage was studied by varying the voltage in the range of 1 ‑ 4 volt/cell volt. The effects of flow rate and initial concentration of ion were studied by changing the flow rate (10, 15, and 20 L/h) and varying the ratio of initial concentration between Li and Co ions (100 - 100, 100 - 400, and 100 - 500 mg/L). The results exhibited that the highest separation capacity of lithium (99.40%) was obtained when using the optimum applied voltage of 2 volt/cell. Low energy consumption would be obtained when using a low voltage for the process separation. The optimum flow rate for the lithium separation using electrodialysis monovalent membrane in this research was 15 L/h. The greater flow rate reduced the current efficiency and increased the energy consumption. When the concentration of cobalt were increased in the range of 100 - 500 mg/L, the results indicated a decrease of current efficiency but an increase of energy consumption showing the influence of concentration of cobalt to transportation of lithium ions and selectivity of monovalent membrane
Using Waste Vermiculite and Dolomite as Eco-Friendly Additives for Improving the Performance of Porous Concrete
Get PDFThe present study investigated the applicability of waste vermiculite and dolomite as fine aggregate, known as appropriate mineral adsorbents to enhance the quality of urban runoff, for improving the mechanical properties of porous concrete. 180 samples were mixed by adding 5-30% vermiculite and dolomite, as fine aggregate, and combining them with ordinary sand; lime sand (combining of 5-15% of each). Results showed that although adding dolomite culminated in a minor reduction of permeability– average of about 30%-, the average of compressive strength was augmented by 120%. Results of compressive strength of dolomite samples were repeated in mixtures containing vermiculite (an increase of 57%). While exploiting vermiculite in high percentages (20, 25, and 30) resulted in an extensive decrease in the permeability (94%), it was improved to an acceptable level (about 40%) after using vermiculite in combination with ordinary sand (lime sand). All dolomite and improved vermiculite mixtures, after combining vermiculite with ordinary sand, had appropriate performance in draining storm-urban runoff; such that in the weakest case, stimulated storm runoffs with heights of 10, 20, 30 and 40 cm were completely drained only after 17, 36, 59 and 87 seconds, respectively. Also, using vermiculite resulted in reducing the concrete weight (about 100 kg). Generally, although a little reduction in the permeability was seen, but using waste vermiculite and dolomite improved the mechanical properties of porous concrete significantly
Reference Stress Approach for Fracture Assessment of Extrados Circumferential Through-Wall Crack at the Interface between Elbow and Pipe Subjected to Internal Pressure
No full textThe fracture assessment of a cracked component can provide a technical support for an effective maintenance and a prevention of catastrophic accident. The present study applies the reference stress method to extend the J-integral solution from the finite element analysis for the Ramberg-Osgood stress-strain relationship to other types of stress-strain relationship. The problem in this study is an extrados circumferential through-wall crack at the interface between elbow and pipe subjected to internal pressure. The finite element results from the literature were analyzed to determine the optimized reference pressure. The reference-stress-based failure assessment curve which incorporated with the obtained reference pressure can be used to estimate the finite-element-based failure assessment curve with a sufficient accuracy in fracture assessment. The failure load predicted from the reference-stress-based failure assessment curve deviated from that predicted from the finite-element-based failure assessment curve within the range of -7% to 11%
Non-linear Site Response Analysis of Soil Sites in Northern Thailand during the Mw 6.8 Tarlay Earthquake
Get PDFOn 24 March 2011, the 6.8 Mw Tarlay Earthquake occurred at the border of Thailand and Myanmar. The earthquake not only resulted in structural building damage but also triggered liquefactions on sandy soils in Northern Thailand. Several site investigations including SPT and shear wave velocity measurements are conducted to study subsoils condition in this area. Ground motions at several seismic stations were recorded during the earthquake. In this study, four soil sites in Chiang Rai and Chiang Mai are selected, including a site at the border of Thailand and Myanmar. Next generation attenuation models are employed to generate the input ground motions for each site. Non-linear finite element analysis is employed to observe soil behaviour under the earthquake. The results showed that liquefaction could happen in the investigated area during an earthquake. The result is confirmed by the liquefaction evidence found in Chiang Rai during the 6.8 Mw Tarlay Earthquake. This research can help raise awareness of the impacts of earthquakes to this region
The Conceptual Framework of the Government-Sponsored Rural Road Improvement Project Evaluation and Selection
Get PDFTo take advantage from locating in the Association of Southeast Asian Nations (ASEAN) mainland region, the Thai government has established a policy of being logistics and transportation hub. The policy has therefore challenged the Department of Rural Roads (DRR) and particularly the Bureau of Rural Roads (BRR) 11, 12, and 14 undertaking responsibility of all rural roads in the south part of Thailand. The BRR strategic plan and implementation have been demanded to reform. This research aimed to create the conceptual framework of route project improvement execution plan for BRRs’ decision-making on project investment prioritization. The focus group interview method was applied to gather factors influencing transportation investment projects in order to develop the criteria of route project improvement prioritization. In addition, the score level of each criteria was also collected through this method. Then, to rank the important criteria, the questionnaire was developed to gain the data of pairwise comparison and the Analytic Hierarchy Process (AHP) method was applied to analyze the data. The results showed that the framework was suitable for the BRRs’ long term route project improvement execution plan while the instant application was appropriated for the BRRs’ short term plan.To take advantage from locating in the Association of Southeast Asian Nations (ASEAN) mainland region, the Thai government has established a policy of being logistics and transportation hub. The policy has, therefore, challenged the Department of Rural Roads (DRR) and particularly the Bureau of Rural Roads (BRR) 11, 12, and 14 undertaking responsibility for all rural roads in the south part of Thailand. The BRR strategic plan and implementation have been demanded to reform. This research aimed to create the conceptual framework of route project improvement execution plan for BRRs’ decision-making on project investment prioritization. The focus group interview method was applied to gather factors influencing transportation investment projects in order to develop the criteria of route project improvement prioritization. In addition, the score level of each criterion was also collected through this method. Then, to rank the important criteria, the questionnaire was developed to gain the data of pairwise comparison and the Analytic Hierarchy Process (AHP) method was applied to analyze the data. The results showed that the framework was suitable for the BRRs’ long-term route project improvement execution plan while the instant application was appropriated for the BRRs’ short-term plan
Information Effect in Taxi Service Double Auction with Opportunity Cost: An Experimental Analysis
Get PDFInspired by the taxi refusal problem, we propose a double auction for taxi services with a variable supply-and-demand fare surcharge. In contrast to a conventional commodity double auction, our taxi service auction involves an opportunity cost that generally increases with time. Therefore, the bidding behaviour differs from that reported in the literature. We investigate experimentally the effects on bidding behaviour of the opportunity costs and private values of drivers and passengers, as well as of the types of given information. In addition, we compare the realized benefits between passengers and drivers. The results show that the degree of sensitivity to private value differs with opportunity cost and that transaction statistics vary with types of the information given to bidders. Moreover, we found that providing more information to bidders does not necessarily lead to better market performance and that giving suitable information to bidders could lead to a balanced benefit between passenger and driver.Inspired by the taxi refusal problem, we propose a double auction for taxi services with a variable supply-and-demand fare surcharge. In contrast to a conventional commodity double auction, our taxi service auction involves an opportunity cost that generally increases with time. Therefore, the bidding behaviour differs from that reported in the literature. We investigate experimentally the effects on bidding behaviour of the opportunity costs and private values of drivers and passengers, as well as of the types of given information. In addition, we compare the realized benefits between passengers and drivers. The results show that the degree of sensitivity to private value differs with opportunity cost and that transaction statistics vary with types of the information given to bidders. Moreover, we found that providing more information to bidders does not necessarily lead to better market performance and that giving suitable information to bidders could lead to a balanced benefit between passenger and driver
Electronic and Ionic Conductivities Enhancement of Zinc Anode for Flexible Printed Zinc-Air Battery
Get PDFZinc-air battery is considered a promising candidate for future energy applications due to its high energy density, safety and low cost. However, poor battery performance and low efficiency of zinc utilization, resulted from passivation effect of the zinc anode, is a major challenge. Thus, in this work, investigation of electronic and ionic conductivities enhancement of the zinc anode for flexible printed zinc-air battery has been carried out. The anode was made from a zinc-based ink, prepared from a mixture of zinc and zinc oxide particles. Carbon black, sodium silicate (Na2SiO3) and bismuth oxide (Bi2O3) were investigated for implementation on the anode. The results showed that performance of the battery increased when carbon black was introduced into the anode as the presence of carbon black improved electronic conductivity of the anode. Again, the battery performed better when Bi2O3 orNa2SiO3 was introduced due to the formation of solid electrolyte interface (SEI) on the anode. The SEI inhibits passivation of zinc active surfaces and provides effective electrolyte access. The battery with Bi2O3 provided the best performance. The highest performance was observed when Bi2O3 content reached 26wt.%. No significant improvement was observed whenBi2O3 concentration increased higher than 26 wt.%.Zinc-air battery is considered a promising candidate for future energy applications due to its high energy density, safety and low cost. However, poor battery performance and low efficiency of zinc utilization, resulted from passivation effect of the zinc anode, is a major challenge. Thus, in this work, investigation of electronic and ionic conductivities enhancement of the zinc anode for flexible printed zinc-air battery has been carried out. The anode was made from a zinc-based ink, prepared from a mixture of zinc and zinc oxide particles. Carbon black, sodium silicate (Na2SiO3) and bismuth oxide (Bi2O3) were investigated for implementation on the anode. The results showed that performance of the battery increased when carbon black was introduced into the anode as the presence of carbon black improved electronic conductivity of the anode. Again, the battery performed better when Bi2O3 or Na2SiO3 was introduced due to the formation of solid electrolyte interface (SEI) on the anode. The SEI inhibits passivation of zinc active surfaces and provides effective electrolyte access. The battery with Bi2O3 provided the best performance. The highest performance was observed when Bi2O3 content reached 26 wt.%. No significant improvement was observed when Bi2O3 concentration increased higher than 26 wt.%