Engineering and Technology Horizons

Effects of Potassium Solutions on Swell Potential of Mae Moh Expansive Soil

2023-09-21T09:02:51+07:00

This paper presents a field experiment of using potassium solutions to reduce swelling of expansive soil in the area of Mae Moh District, Lampang Province, Thailand. Based on the fact that the difference between montmorillonite in expansive soil and illite in non-expansive soil is the silica-gibbcite structure of the former was bonded by water molecules but those structures of illite was bonded by potassium ions. Therefore, an assumption of this research was if the expansive soil were soaked in potassium solution, monmorillonite may change to illite, and the soil should no longer swell. The field experiment was conducted by drilling holes of approximately 2 meters depth. Then, released potassium hydroxide in the forms of solution and flakes as well as potassium chloride solution and potassium nitrate solution into the holes. Kept the holes fill with the solutions at all time. After 30 days and 90 days, drilled other holes nearby the solution-fill holes to collect soil samples for laboratory tests. The investigation revealed that only the 20% potassium hydroxide can reduce the swelling of Mae Moh expansive soil. The X-ray diffraction test discovered that after 30 days of applying KOH solution to the expansive soil stratum, only illite and muscovite but montmorillonite was found, then after 90 days only muscovite was found. Based on academic articles in chemistry and geology, the transformation of montmorillonite to illite, and transformation of illite to muscovite are possible. The study of using potassium hydroxide solution should be studied extensively because it will be useful for existing buildings.

A Mixed-integer Linear Programming Model for Solving Multi-item Uncapacitated Lot-sizing Problems with Storage Capacities Limitations: A Case Study of an Apparel Manufacturing Company

2023-09-11T08:58:49+07:00

This study aimed to use a mixed-integer linear programming model to solve the multi-item uncapacitated lot size problem with storage capacity limitations for apparel manufacturing. In real-world operations, sometimes the storage capacity of cloth rolls can be insufficient at any given time. This would be because the sum of the remaining cloth rolls from the previous period and the receiving cloth rolls from the existing period would be a vast number. Furthermore, the extra cloth on the rolls would have to be carried and kept in the production line. Consequently, this caused the late issue of the distribution of the material, the loss of the cloth rolls, and the failure to count the cloth rolls. As a result, we conducted a multi-item cloth roll replenishment plan to meet the production line's demand and keep all the inventory and receiving cloth rolls. Using mixed-integer linear programming, the multi-item lot size of each period and the sum of the cloth, ordering, and holding costs was calculated, including the number of occupied cloth racks that did not exceed the number of available cloth racks in the cloth storage. Then, this result was compared with the calculation of a mixed-integer linear programming model based on the procurement policies of a case study company. This study used OpenSolver and GAMS/CPLEX software to calculate the solutions. The results found that in using the procurement policy, we could provide the maximum number of occupied cloth racks, about 368 racks, or 2.78 times the racks on the available shelves of the cloth storage. The result of the proposed model indicated that the number of occupied cloth racks to be installed did not exceed the number of available racks on the shelves. The total cost of the model of the procurement policy was less than the proposed model by about 0.26 percent because ordering occurred only about 25 times.

Analysis and Performance Evaluation of a Cubic Buck Converter

2023-09-29T14:49:39+07:00

This paper presents an analysis and performance evaluation of a cubic buck converter. The converter is developed from three buck converters connected in series and uses only one active switch. The proposed circuit has a voltage step-down gain equal to the cube of that provided by a single buck converter. Therefore, it is suitable for use in applications requiring a high voltage step-down, e.g. the conversion of a high DC voltage produced by solar arrays to directly supplying a low-voltage DC load. In the paper, the circuit analysis of the cubic buck converter is performed. The prototype circuit operating with the input voltage of 150 V, the output voltage of 5 V, the load current of 1–10 A and the switching frequency of 100 kHz is implemented. Experimental results confirm that the prototype circuit can maintain the output voltage 5 V throughout the load current range. In addition, the voltage and current measurement results are consistent with the theoretical analysis.

Non-destructive Moisture Content Testing for Soil Brick Using Capacitive Measurement With 50 MHz Radio Frequency

2023-10-30T11:54:27+07:00

This research paper presents a soil brick moisture measurement by capacitive measurement with radio frequency of 50 MHz and the soil brick as the dielectric material sandwiched between the conductive plates of the capacitor. The moisture content of the soil brick was considered from the capacitance storage capacity of the capacitor. The proposed measurement consisted of a voltage-controlled oscillator, capacitance measurement circuit, radio frequency amplifier, radio frequency detector, and microcontroller unit. After that, a circuit was built and assembled to the radio frequency soil moisture meter of soil bricks for evaluate the soil brick with width of 20 cm, length of 40 cm and the thickness of 20 cm. There are four types of soil brick with moisture of 10% to 30% and 10 times of iterations. From measured results, it was found that the dielectric constant and capacitive value are directed variation with moisture content of soil bricks. Therefore, the moisture content of soil bricks can be found by capacitive measurement. From the measured results, it accurate when comparing the standard measurement with an error of 4–16%.

Setup Time Reduction for Toothpaste Tube Filling Machine: A Case Study of a Contract Toothpaste Manufacturing Company

2023-11-03T15:09:07+07:00

This research aimed to find ways to reduce the idle time and improve the toothpaste tube filling machine setup procedure. The toothpaste manufacturing industry has many kinds of products nowadays, so the production process would need to frequently change its production plan, thus causing the number of machine setup times to increase. As such, the toothpaste tube filling machine would be unable to run simultaneously. According to the study, the average machine setup time on the filling machine was 157.1 minutes per time. This was more than the planned machine setup time of about 67.1 minutes, or 74.55 percent. The researchers presented the single-minute exchange of die and the eliminate, combine, reduce, and simplify approaches to reduce the average time of the machine setting by about 124.6 minutes per time, or 20.69 percent. The evaluation results of the process performance before and after the improvement by measuring the overall equipment efficiency from 41.66 percent to 58.61 percent increased by 16.95 percent.

A Study on Improvement to Increase Efficiency of U–Turn Opening on Charan Sanit Wong Road at Bang O Fire Station U–Turn

2023-11-06T10:00:49+07:00

The U–Turn is a risky point where there are frequent road accidents. There are many factors leading to the problem of the U–turn such as the physical characteristics of the U–turn, location of U–turn median opening, insufficient sight distance, risk spot around the U–turn without traffic management and safety and factors caused by the driver. This paper presents the results of a study on improvement to increase efficiency of U–Turn Opening on Charan Sanit Wong Road at Bang O Fire Station U–Turn. By studying the improvement pattern of the U–turn from the past to the present and the pattern of improvement measure. Traffic microsimulation model was developed using VISSIM software and evaluated the traffic efficiency. The results were analyzed to determine the Time–To–Collision (TTC) using the SSAM program to assess traffic safety from the number of conflict points. The results showed the pattern of improvement measure with improved physical characteristics by increasing the length of the storage lane and restricted U–Turn for motorcycle measure could increase traffic efficiency. The average travel time was reduced by 1% and 10% and reduced the average delay by 12% and 31% in the directions to Rama VII and Pinklao, respectively. The safety analysis results showed the pattern of improvement measure which has a Time–To–Collision (TTC) value of 0.88 seconds and has the least number of conflicts point compared to previous improvement pattern.

A Study of Efficiency and Economic Value of Grade Separated Construction Project: Case Study of Grade Separated Without Ramp across The Sri Ayutthaya Intersection Bangkok

2023-12-22T09:09:50+07:00

This research was conducted to analyze the efficiency and economic value of grade separated construction projects in a large city due to heavy traffic volumes. This is consistent with the current situation where traffic volumes are continually increasing. In order to reduce fuel consumption, accidents and travel time. In this research, the efficiency and economic value of grade separated without ramp across Sri Ayutthaya intersection will be studied, Bangkok (Thailand), is considered in the form of an underpass through the intersection by using the VISSIM program to create and develop micro simulation traffic models. Then, the economic cost-benefit analysis of the project is evaluated by considering the economic worthiness of the project from a comparison between the case with the project and without the project. The economic worthiness of the project is analyzed by using Net Present Value (NPV), Benefit-Cost Ratio (B/C ratio) and Internal Rate of Return (IRR). From the results of this study, it was found that after developing the current area, which is a ground level intersection into an underpass. Traffic at intersections will be more efficient. And helps reduce traffic congestion at intersections. This is because the average delay of each type of vehicle decreased after the project. Performance measures at intersections can be summarized as the average vehicle delay in the project start year (2027) for motorcycles decreased from 364.48 seconds/vehicle to 85.93 seconds/vehicle, passenger cars decreased from 369.35 seconds/vehicle to 78.42 seconds/vehicle, trucks decreased from 282.19 seconds/vehicle to 78.96 seconds/vehicle, and buses decreased from 420.47 seconds/vehicle to 65.07 seconds/vehicle. And it can be concluded that the project of grade separated construction in the form of an underpass across Sri Ayutthaya Intersection. It is economically worthwhile and suitable for investment. Because the net present value (NPV) in the 15th year of the project (2041) is equal to 1,752.18 million baht, which is greater than 0, the benefits-costs ratio (B/C Ratio) in the 15th year of the project (2041) is equal to 3.61, which is greater than 1, and the internal rate of return (IRR) at the 15th year of the project (2041) is equal to 42%, which is greater than 12%.

Study of Problem and Effect Mitigation Technique of Unbalance Capacitance in 500 kV Single Phase Transformers

2023-09-29T14:50:35+07:00

This article presents the study of the effect of unbalanced stray capacitance in single-phase 500 kV power transformers and establishes the mitigation technique. The power transformers were operated in Wang Noi Substation for transmitting the electrical power. There are 3 units of single-phase power transformer. Previously, a transformer of
phase B failed after being serviced for several years. Thus, the new power transformer was ordered instead of the failed one. However, once the new system had been operated, the hotspots at the surge arrester of tertiary winding (22 kV) were found and the unbalance of phase voltages was observed, resulting in overvoltage as a root cause of the problem. Once a thorough investigation was done, it was found that there was an effect of unbalanced stray capacitance between tertiary winding and ground core since the new power transformer has some different designs compared with the remaining. Hence, the mitigation technique was performed by adding the capacitor parallel to the tertiary winding until the voltage balance was achieved. Simulation with the PSCAD program was performed to determine the optimum value for additional capacitors, i.e., voltage balance, using an iterative method. In this article, the capacitors used for additional were capacitor voltage transformers, which have been installed. As a result of the troubleshooting, the voltage at the 22 kV bus was more balanced as well as not causing overvoltage, and the hotspots at the surge arrester of tertiary winding were not detected resulting in gaining the stability and reliability of using these transformers.

Effects of Synthesis Method on Catalytic Activities of Ag/TiO2 Catalyst in CO Oxidation Reaction

2023-11-06T08:48:41+07:00

Supported silver catalysts on titanium dioxide have been synthesized by three different methods to compare catalytic activity in CO oxidation. The catalysts were prepared by the wet impregnation method with 10 mole% of silver. In the first method, the silver catalysts were impregnated on the titanium dioxide nanoparticles (Ag/TNP), while in the second method, the silver catalysts were impregnated on the titanium dioxide nanotubes (Ag/TNT). The third method, the silver catalysts were impregnated on the titanium dioxide nanoparticles before the nanotube process (Ag/TNP-TNT). The Ag/TNP and Ag/TNT catalysts showed highly dispersed silver nanoparticles with an average particle size of less than 5 nm on the surface of titanium dioxide, whereas the Ag/TNP-TNT catalyst exhibited much lower dispersion of silver nanoparticles. The highly dispersed silver on the titanium dioxide resulted in a large number of surface active sites (Ag⁰). The catalytic activity test found that the Ag/TNT catalysts with the highest number of active sites (2.20 × 10²⁰atom/g-catalyst) exhibited higher CO oxidation activity than the Ag/TNP and Ag/TNT catalysts with 100% CO conversion at 125°C.

Improving the Water Distribution System to Support a Future Water Demand in the Western area of Chao Phaya River

2023-10-19T10:25:24+07:00

Bangkok and its vicinities’ city areas are expanding and are requiring the higher water supply from the Maha Sawat and Bang Bua Thong service areas of the Metropolitan Waterworks Authority. As a result, the existing water network system’s water pressure may decrease and be inadequate to supply the water to the service areas. The study utilizes the water pipe network model, EPANET, of the Maha Sawat and Bang Bua Thong service areas that has been calibrated previously. The model was satisfyingly calibrated and accepted by balancing the water volume and pressure level. In this research, the model is used to evaluate the existing pipe network system of the study area under the future water demand condition in the next five years. Then, the model is used to define optimal location of a new pumping station that needs to increase the water distribution system efficiency and its stability. Five proposed location that need to increase the water distribution system are assumed to use the same pumping pattern and supply pressure. Each pumping station supplies a pressure head at least eight meters and use the water pressure multipliers from the Phet Kasem pumping station for each period. By using the average water pressure and the contour pressure of water distribution area as an indicator comparing the five pumping locations individually, the result showed that the best location of the new pumping station is located on Highway No.345 km.5+735.00.

The Attitudes of Pedestrians when Using Crosswalks with Distinct Traffic Lanes: A Case Study on Chaeng Watthana Road, Lat Krabang Road, and Kingkaeo Road

2024-01-02T10:19:52+07:00

One of the most important modes of transportation in cities and suburbs is walking. In large urban areas, walking reduces traffic congestion. However, data indicates that Bangkok is responsible for 1 in 3 pedestrian accidents per year, with an average of 900 such incidents taking place there. Furthermore, based on data collected from 2013 to 2017, car-pedestrian collisions are categorized by the highest severity index due to the average of 55 fatalities per 100 accidents. These statistics show that there are, on average, 740 pedestrian-vehicle incidents annually. The data indicates that to lower the number of pedestrian fatalities, walking mode needs to be enhanced. Consequently, the investigator was interested in determining how crossing facilities and people's attitudes are related. The goal of this research is to examine significant variables that influence how pedestrians feel about crossing the street. A questionnaire was used to collect data, which was separated into two sections: attitude about crossing the road and attitude regarding safety when crossing the road. The study's sample crosswalks are located on Chaeng Watthana Road, Lat Krabang Road, and King Kaew Road. Descriptive statistics and linear regression were employed in the analysis to consider social characteristics, variables related to past road crossing experience, variables regarding attitudes toward using road crossings, and variables regarding crossing facilities. Results from 412 questionnaires show that the number of traffic lanes, vehicle volume and vehicle speed were determined to be the primary factors significantly reducing the attitude of security that one feels when crossing the street. Furthermore, the outcomes held up when descriptive statistics were used for analysis. It was discovered that push-button traffic lights had the biggest influence on attitudes of safety when it came to attitudes regarding crossing facilities.

A Directional Control Auxiliary Thrust System to Increase the Forward Speed of a Quadcopter UAV

2024-01-12T15:44:24+07:00

This research introduces a method to increase the horizontal speed of a quadcopter UAV using an auxiliary thrust system that can be adjusted in direction. The researcher used thrust vectoring control to align the thrust direction with the unmanned aircraft's longitudinal axis. A method for controlling a device mechanism using a proportional-integral-derivative (PID) control system. Based on the test results, it has been concluded that the Ziegler–Nichols Method in P controller, the Ziegler–Nichols Method in PD controller, and the Trial-and-Error method in PID controller are the most effective methods for maintaining system stability and achieving the setpoint. It took 0.693, 1.441, and 0.563 seconds respectively to reach the desired value. The researcher used computational fluid dynamics and equations of motion to simulate a UAV's speed. The simulation results of using 25% additional thrust while moving at a 2-degree angle showed that the unmanned aerial vehicle's speed increased by 35.3% compared to the unmanned aerial vehicle without the auxiliary thrust system. When the pitch angle was increased to 5 degrees, the speed of the UAV increased by 15.9%. At higher pitch angles of 10 degrees, the UAV's speed increased by 6.86%. Finally, at pitch angles of 15 degrees, the speed of the UAV increased by 4.97%.