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
The synthesis using electrons as reagents instead of oxidants is a method for synthesizing drug molecules in a way that reduces the use of chemicals, thereby minimizing environmental pollution.
คณะสถาปัตยกรรม ศิลปะและการออกแบบ
The purpose of this research aims to guidelines the identity design for high-speed rail stations, which are divided into four steps: 1) Survey and analysis of identity at the high-speed train stations, including subway in Japan and Taiwan. 2) Comparison the perception of the environment by the questionnaire at BTS, MRT BL, Airport Rail Link (AERA1), and MRT PPL in Bangkok from passengers 800 passengers. 3) Survey and analysis the perception of identity at the MRT Blue Line by questionnaires 800 passengers at Wat Mangkorn, Sam Yod, Sanam Chai, and Itsaraphap stations. 4) To analysis with the descriptive statistics and one-way ANOVA. Study and survey of the high-speed rail environment from Bangkok to Nong Khai, then synthesize the identity design guidelines by 12 experts with structured interviews to summarize the conceptual framework for identity design for high-speed rail stations. The results shown that the identity of train stations in Japan and Taiwan is designed based on architectural and historical concepts that align with the local environment, society, and lifestyle near the stations. This design approach is evident at stations serving as significant tourist attractions and in the surrounding environment, including external buildings and nearby public transportation connections, as well as entrance and exit doors to the station. In summary, four types of identities have been identified: 1) The Identity Historical and Architectural 2) The Identity of Culture 3) The Identity from Cartoons and 4) The Identity of Art and Design
คณะเทคโนโลยีการเกษตร
Dwarf whipray (Brevitrygon heterura) is a common species found in a local market in the Gulf of Thailand. However, like many other species of stingrays, it is threatened by overfishing and habitat destruction. Therefore, an accurate species identification is crucial because conservation efforts may vary depending on the species. This study aims to understand morphological variation of B. heterura in the Gulf of Thailand by morphometric study and genetic analysis. During October 2022 and February 2023, we obtained 49 samples from research vessels fish landing ports and local fish markets. We observed two distinct groups based on 43 morphological variables/ratios. B. heterura samples from Chanthaburi, Rayong, Chonburi, Samut Sakhon, Nakhon Si Thammarat and Songkla provinces, called “group A," typically have longer snout length than those from Prachuap Khiri Khan provinces, called “group B" according to external morphological characters for species identification. Three morphological variables/ratios were significantly different between groups A and B. Main characters to explain intraspecific variations between group A and group B are further discussed. DNA barcoding based on a fragment of the cytochrome c oxidase subunit I (COI) gene were obtain from eight samples of group A and eight samples from group B. Pairwise percent sequence divergence (p-distance) for COI between group A and group B were 0.0-2.5. This study contributes to the understanding of variations of morphology and genetics of B. heterura in the Gulf of Thailand.