Journal of Engineering, RMUTT

Design of Propulsion Power and Test of Stopping Systems of a Prototype Train

Nopporn Preamjai — 2023-12-26

The purpose of this article is to study the propulsion power and stopping systems of a prototype train using a push-pull motor linear actuator. The prototype train is controlled by an Arduino microcontroller board and runs on a 0.459-meter-wide track with a total of 3 simulated stations totaling a distance of 100 meters. Each station has a distance of 50 meters. The test of the stopping systems of the train is divided into 2 parts: 1. Changing the train speed: There are three speeds, including 2.7, 3.9, and 4.5 kilometers per hour. 2. The change in weight of the train has three values: 360, 420, and 480 kilograms. The experimental results found that the appropriate speed and weight of the prototype train that causes the train to stop closest to the station is 3.9 kilometers per hour and the train's weight is 480 kilograms. Furthermore, there is an average stopping distance for the outbound and return trips of -3.0 and -3.2 centimeters (stopping before reaching the station), respectively.

The Use of Rapid Setting Mortar as Floor Leveling in Polyurethane Coating

Sivagorn Deechuay — 2023-12-26

The purpose of this paper was to determine rapid setting mortar mix design for the use as a leveling layer in polyurethane floor coating. Rapid setting mortar required superplasticizer and accelerator to satisfy with the flow rate of mortar within 130±5 percent and compressive strength of mortar not less than 200 and 400 ksc at 8 hours and 24 hours, respectively. For at least 95% probability of passing the required compressive strength, target means should be 217 ksc and 435 ksc, respectively. Then mortar mix proportions were designed according to the ACI 211.1-91 method. Then mortar mix proportions obtained were examined with the flow table test, the compression test and the tensile test. The mortars were cast within a range of atmospheric temperatures, 29-32°C, 32-34°C and more than 34°C. Results from the study showed that the optimum mortar proportion was water to cement ratio of 0.35, Portland cement type 3 content of 588 kg/m³, superplasticizer 1.2% by weight of cement, and the accelerator 0.28% by weight of cement. The mortar reached compressive strength 217 ksc in 8 hours for the casting temperature 29°C-32 °C. And at 24 hours, mortar could reach compressive strength of 435 ksc at all of temperature ranges without adding accelerator. Although the tensile strength of the rapid setting mortar was less than polyurethane, in the application of the rapid setting mortar as floor leveling layer together with the polyurethane coating, no crack or peeling at the surface was found. Thus, rapid setting mortar might be used as floor leveling in place of the polyurethane composite at the much lower cost of construction

A Study of Delay Factors and Preventive Guidelines in the Attitudes of Construction Contractors for Housing Projects in Bangkok and its Vicinity

jaruwat panjindawan — 2023-12-26

This research aims to investigate contractors’ attitudes towards factors causing construction delays and measures for prevention of construction delays in Bangkok and its vicinity. In particular, quantitative research was adopted. A questionnaire was administered to collect the data from 86 housing projects selected through simple random sampling based on Yamane’s formula for sample size determination. Statistics used to analyze the data included the relative importance index (RII) and factor analysis (FA). The results demonstrated that the three most notable factors contributing to construction delays were identified as: 1) a shortage of skilled or experienced workers; 2) delayed delivery of construction materials; and 3) changes in the prices of construction materials. In addition, all 33 factors of construction delays were thematically classified into eight categories of factors by using factor analysis (FA) as follows: 1) project and risk management; 2) labor; 3) external factors; 4) communication and coordination; 5) construction budgets; 6) construction planning; 7) contractor management; and 8) laws, regulations and contracts. Moreover, measures for prevention of construction delays are proposed to enable contractors to recognize the problems and to minimize the potential damage attributed to delays in construction

Development of Particleboard from Durian Branch Waste for Adding Value to Agricultural Waste Material and Promoting Zero Waste Concept

ภควัต เกอะประสิทธิ์ — 2023-12-26

This research aims to develop particleboard from durian (Monthong variety) branch waste for use as a decorative material. The ratio of durian branch waste to Polymeric Diphenyl Methane Diisocyanate (pMDI) was designed and edited into six ratios with varying amounts of pMDI. The particleboard samples were cast using heat at 150°C for 7 minutes and tested following TIS.876-2004 (particleboard product) standards. According to the results, the particleboards with a density of 600 kg/m³, 8% pMDI, and mixed durian wood chips (shaved wood chips and ground wood chips) were suitable for decoration work. The properties of the particleboard included a density of 597.25 kg/m³, 4.48% moisture, 5.34% thickness swelling, 6.05 MPa bending strength, 378.25 MPa elastic modulus, and 0.37 MPa tensile strength perpendicular to the surface. The developed particleboard from durian branch waste can add value and reduce the amount of agricultural waste left in durian orchards in accordance with the zero waste concept

Automated Plant Watering System using Microcontroller with Notification

Pairote Thongprasri — 2023-12-26

The advancement of Internet technology has resulted in an increased role of Internet of Things (IoT) technology in our daily lives, including its application in agriculture. It enables users to monitor operations in real-time. This paper presents an automatic plant watering system through sprinklers on an area of 119 square meters in which trees and shrubs are already planted with an area of 92 and 27 square meters, respectively. The water supply is stored in a 5-meter high reservoir, utilizing potential energy to determine the fluid pressure. The results were calculated to determine the number of sprinklers that can be used effectively without the need for water pumps in order to reduce costs. The system has 2 operating modes: MANUAL and AUTO, processed by NodeMCU microcontroller. It can operate according to predefined time and conditions. The sprinklers are controlled by solenoid valve, using soil moisture and water level in the reservoir as primary factors. The system can control and display real-time data through the Blynk mobile application and notify users of its operation via the LINE messaging application. The system requires the soil moisture to be less than 70% and the water level in the reservoir to be above 30% in order to function. In both modes, the experimental results demonstrate that the system can effectively supply water to plants and accurately notify the users.

Simplified Method for Analyzing Slope Stability of Clay Layer of Increasing Strength With Depth

Wanwarang Ratananikom — 2023-12-26

Stability analysis of slopes plays a crucial role in geotechnical engineering which is often associated with excavation and filling works. It helps designing the layout of a newly constructed slope and assessing the risk of failure of an existing slope. Moreover, it enables a strength of soil of a failed slope to be back-calculated. Nowadays, there are a number of slope stability analysis methods, each of which has different hypothesis, limitations, and complexities. Most detailed slope stability analyses involve computational tools, i.e. computer software with a finite element or limit equilibrium methods. As a result, an initial assessment of slope stability on site is difficult in practice. Therefore, the objective of this research is to propose a set of slope stability charts for homogeneous clay with increasing strength with depth by Morgenstern and Price method. It also considers the factors affecting slope stability such as slope angle, slope height, depth of firm subsoil, surcharge factor, and tension crack factor. The result will be beneficial for preliminary estimation of slope stability analysis. Based on the findings, the slope stability chart developed in this study is considered reliable for practical applications. Errors of safety factors analyzed from the research are low in case of (i) the surcharge factor without considering the tension crack factor and (ii) the tension crack factor without considering the surcharge factor. Nevertheless, it is important to note that the safety factors obtained in this research are comparatively lower than those derived from the GeoStudio 2012 analysis when considering both the surcharge factor and tension crack factor simultaneously, particularly in situations with steep slope angles.

Development of Management Model and Production Planning for the Ban Haad Mango Community Enterprise

Wanita Boonchom — 2023-12-26

This research aimed to study the management model and mango production planning. The qualitative research approach utilized the semi-structured interview as a data collection tool, involving a total of 10 key informants participating. The quantitative research method applied mathematical model using linear programming for mango production planning. Research has found that management by an experienced group leader with leadership qualities, close relationships among members within a kinship system typical of rural societies, coming together to distribute tasks based on skills, and serving as a learning center, results in a learning society. This aligns with government policies to create local networks, benefiting members by reducing production costs, increasing output, and enhancing export value. This model is described by the MASEE Model, consisting of: M: Management, A: Assignment (task delegation based on the group's operational structure), S: Social learning, E: Empathy (skills in understanding others' feelings), E: Engagement (members feeling a sense of ownership in the organization). Furthermore, from a mathematical perspective, the case study farmer group should utilize 73.53% of their total land for mango production to meet the demand for each period. Therefore, adapting a new working model, applying a mathematical approach to plan mango production for each period, can help the case study farmer group plan their mango production more efficiently, considering labor and land constraints

The Control System of the Machine for Dropping Soap into Molds

Chinoros Laoongwan — 2023-12-26

The Control System of the Machine for Dropping Soap into Molds to increase the efficiency of the production process for a group of housewives in agriculture. The researcher applied the innovation and technology for its design. The micro-controller system of Arduino UNO was used for the operational processing of the machine. The important components of the system were the filling tank, the control system of the injector operation, the control system of dropping length, and the heat set. The machine was designed with 2 injectors namely injector A and injector B. The study factors were the operational duration of injectors, the appropriate dropping length, and the weight of soap cakes which were produced from injector A and injector B. The findings were that at the duration of valve opening at 10 seconds and the appropriate dropping length at 6 centimeters, the average weight was at 100.55 grams for the injector A and 100.62 grams for the injector B which both were not below the setting value at 100 grams. The flow of liquid soap can be dropped continuously and consistently even though the quantity of soap liquid was low. The Control System of the Machine for Dropping Soap into Molds produced the maximum 720 cakes per hour from 2 injectors. Increased more than 6 times with the labor force does.