The railway brake system usually uses compressed air brake system which uses high-pressure air to press the brake shoe on the surface of the wheel to reduce the speed of the train. Repeated friction generates heat at the contact surface, increasing thermal stress on the cast iron brake shoe. The purpose of this study is to investigate the thermal stress on a prototype of cast iron brake shoe using the finite element method compare the analytical results to the actual brake shoe and redesign a brake shoe prototype to reduce thermal stress. Based on the results of the thermal stress study using the finite element method, it has shown that the location of the thermal stress on the prototype brake shoe according to the location of the crack on the real brake shoe. The brake shoe's design which includes single notch in the center of brake shoe which is can help to reduce thermal stress. The results from this study should be validated with the results from the field test to evaluate both of thermal distribution and braking efficiency in term of braking distances as well.
ระบบเบรกของรถไฟนิยมใช้ระบบเบรกแบบลมอัด โดยใช้อากาศแรงดันสูงกดแท่งห้ามล้อไปสัมผัสกับผิวของล้อเพื่อลดความเร็วของรถไฟ เมื่อเกิดการเสียดสีกันซ้ำ ๆ จึงเกิดความร้อนขึ้นบริเวณผิวสัมผัส ทำให้เกิดความเค้นสะสมเนื่องจากความร้อนบนแท่งห้ามล้อวัสดุเหล็กหล่อ งานวิจัยนี้จึงมีวัตถุประสงค์เพื่อศึกษาความเค้นเนื่องจากความร้อน (Thermal stress) บนแท่งห้ามล้อวัสดุเหล็กหล่อรูปแบบต้นแบบด้วยระเบียบวิธีไฟไนต์เอลิเมนต์เพื่อเปรียบเทียบผลการวิเคราะห์ที่ได้กับแท่งห้ามล้อชิ้นงานจริง และออกแบบแท่งห้ามล้อวัสดุเหล็กหล่อในรูปแบบใหม่เพื่อลดความเค้นเนื่องจากความร้อนที่เกิดขึ้น
คณะวิทยาศาสตร์
This special project aims to develop and compare the performance of gold price prediction models using quantitative variables and news text data. The study incorporates nine key predictors, including Brent crude oil prices, WTI crude oil prices, silver prices, platinum prices, the U.S. Federal Reserve's policy interest rate, the Nikkei 225 index, the Dow Jones Industrial Average, the S&P 500 index, and daily news articles from Bangkok Business News. Relevant news data will be processed using Natural Language Processing (NLP) techniques and integrated with three predictive models: Gradient Boosting, Machine Learning Models, and Regression Analysis. The model performance will be evaluated using three key metrics: Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and the Coefficient of Determination (R*). This research aims to develop a predictive model that effectively utilizes both quantitative variables and news data to enhance gold price forecasting, providing valuable insights for investors and analysts.
คณะวิทยาศาสตร์
In this paper, Vanadium dioxide (VO2) thin-film devices with two different use cases have been redesigned to introduce an asymmetrical resonant cavity structure. The structure is designed with the goal of enhancing the optical performance of the central VO2 layer and has an anti-reflection property in the cold state. The advantages and limitations of such a design are discussed.
คณะอุตสาหกรรมอาหาร
Coffee is a critical agricultural commodity to be used to produce a premium beverage to serve people worldwide. Coffee microbiome turned to be an essential tool to improve the bean quality through the natural fermentation. Therefore, understanding the microbial diversities could create the final product's better quality. This study investigated the natural microbial consortium during the wet process fermentation of coffee onsite in Thailand to characterize the microorganisms involved in correlation toward the biochemical characteristics and metabolic attributes. Roasting is another important step in developing the complex flavor/ aroma that make coffee to be enjoyable. During the roasting process, the beans undergo many complex and alternatively change in the physicochemical properties from the gained substances in the fermentation process. The changing in the formation of the substances responsible for the sensory qualities, physicochemical/ aroma attributes as well as the health benefits of the final product. Using the starter culture could also develop the distinguished characteristics of coffee (Research collaboration with Van Hart company)