{"title":"Numerical Study on Ultimate Strength of Non-uniform Corroded Tubular T-joints under Compression","authors":"Vu Dan Chinh, Hà Thi Thu Nguyên","doi":"10.7736/jkspe.023.044","DOIUrl":"https://doi.org/10.7736/jkspe.023.044","url":null,"abstract":"","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135255119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Condensation is an important research topic that ensures increased energy efficiency. Our researchers aimed to optimize heat transfer in industrial heat exchanger tubes through surface modification. We first succeeded in fabricating superhydrophilic and superhydrophobic tubes using surface modification. We observed the condensation phenomenon on the outside of the tube and evaluated the heat transfer performance through a condensation experimental facility. As a result, we found that the condensation heat transfer efficiency of superhydrophobic tubes is superior to that of conventional tubes. However, the heat transfer efficiency of the superhydrophobic tube reduced with an increase in saturation. To improve performance degradation, superhydrophilic and superhydrophobic hybrid tubes were fabricated and evaluated for their potential to improve heat transfer efficiency. As a result, we found that the liquid film generated by filmwise condensation on the superhydrophilic surface swept past the residual droplets generated by dropwise condensation on the superhydrophobic surface, resulting in the best heat transfer performance. Our results break the stereotypes of previous studies and provide a new paradigm for achieving optimal heat transfer performance on large-area curved surfaces. This research is expected to be widely applied in a variety of industries where energy efficiency is critical.
{"title":"Study of Condensation Heat Transfer Enhancement Using Micro/Nano Surface Modification Techniques","authors":"Younghun Shin, Kwon-Yeong Lee, Woonbong Hwang","doi":"10.7736/jkspe.023.058","DOIUrl":"https://doi.org/10.7736/jkspe.023.058","url":null,"abstract":"Condensation is an important research topic that ensures increased energy efficiency. Our researchers aimed to optimize heat transfer in industrial heat exchanger tubes through surface modification. We first succeeded in fabricating superhydrophilic and superhydrophobic tubes using surface modification. We observed the condensation phenomenon on the outside of the tube and evaluated the heat transfer performance through a condensation experimental facility. As a result, we found that the condensation heat transfer efficiency of superhydrophobic tubes is superior to that of conventional tubes. However, the heat transfer efficiency of the superhydrophobic tube reduced with an increase in saturation. To improve performance degradation, superhydrophilic and superhydrophobic hybrid tubes were fabricated and evaluated for their potential to improve heat transfer efficiency. As a result, we found that the liquid film generated by filmwise condensation on the superhydrophilic surface swept past the residual droplets generated by dropwise condensation on the superhydrophobic surface, resulting in the best heat transfer performance. Our results break the stereotypes of previous studies and provide a new paradigm for achieving optimal heat transfer performance on large-area curved surfaces. This research is expected to be widely applied in a variety of industries where energy efficiency is critical.","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135248649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Study on Defect Detection Model of Bone Plates Using Multiple Filter CNN of Parallel Structure","authors":"송연 이, 용정 허","doi":"10.7736/jkspe.022.106","DOIUrl":"https://doi.org/10.7736/jkspe.022.106","url":null,"abstract":"","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135255633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Young-Woo Im, Geon-Taek Kim, Hyeon-Sang Shin, Kang Min Kim, Bu Hyun Shin, Jong Won Lee, Jinsung Rho
{"title":"Optimization Design of Student KSAE BAJA Knuckle Using SLM 3D Printer","authors":"Young-Woo Im, Geon-Taek Kim, Hyeon-Sang Shin, Kang Min Kim, Bu Hyun Shin, Jong Won Lee, Jinsung Rho","doi":"10.7736/jkspe.023.028","DOIUrl":"https://doi.org/10.7736/jkspe.023.028","url":null,"abstract":"","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135254544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lately, due to the concentration of population in metropolitan areas, traffic congestion in the hub city has occurred, and future mobility AAM development is undergoing active progress to solve this situation. Accordingly, reducing noise pollution, which is pointed out as one of the problems of AAM, is an essential technical issue for urban operation. In this study, a duct, which is a representative aerodynamic noise reduction method, was used, and numerical analysis was performed using ANSYS FLUENT, a CFD software, according to the shape of struts in the duct. The FW-H of the transient-state LES model was used, and the steady-state analysis value was used as the initial value to save analysis time. Case 1 without strut, Case 2 with strut of an airfoil section, and Case 3 with strut of a rectangle section were designed and compared at a rotational speed of 6,000 RPM. Compared to Case 1, Case 2 and Case 3 showed improved thrust by about 7% and 2%, respectively. Compared to Case 2, Case 3 showed reduced OASPL from a minimum of 0.0793 dB to a maximum of 1.0072 dB. It was found that shapes of strut in the duct significantly affect thrust and aerodynamic noise.
{"title":"An Aeroacoustics Study on AAM Blade in Duct with Different Strut Shapes","authors":"Sang-Hyun Kim, Jihun Song, Dong-Ryul Lee","doi":"10.7736/jkspe.023.060","DOIUrl":"https://doi.org/10.7736/jkspe.023.060","url":null,"abstract":"Lately, due to the concentration of population in metropolitan areas, traffic congestion in the hub city has occurred, and future mobility AAM development is undergoing active progress to solve this situation. Accordingly, reducing noise pollution, which is pointed out as one of the problems of AAM, is an essential technical issue for urban operation. In this study, a duct, which is a representative aerodynamic noise reduction method, was used, and numerical analysis was performed using ANSYS FLUENT, a CFD software, according to the shape of struts in the duct. The FW-H of the transient-state LES model was used, and the steady-state analysis value was used as the initial value to save analysis time. Case 1 without strut, Case 2 with strut of an airfoil section, and Case 3 with strut of a rectangle section were designed and compared at a rotational speed of 6,000 RPM. Compared to Case 1, Case 2 and Case 3 showed improved thrust by about 7% and 2%, respectively. Compared to Case 2, Case 3 showed reduced OASPL from a minimum of 0.0793 dB to a maximum of 1.0072 dB. It was found that shapes of strut in the duct significantly affect thrust and aerodynamic noise.","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135248648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Control Method of Electric Gripper Using Current Control System","authors":"Ji-Hye Min, Gab-Soon Kim","doi":"10.7736/jkspe.023.038","DOIUrl":"https://doi.org/10.7736/jkspe.023.038","url":null,"abstract":"","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135255207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hyeongyeong Jeong, Hyunbin Park, Jaemin Shin, Hyeonjae Jeong, Baeksuk Chu
{"title":"Autonomous Fine Dust Source Tracking System of the Water Spray Robot for High-rise Building Demolition","authors":"Hyeongyeong Jeong, Hyunbin Park, Jaemin Shin, Hyeonjae Jeong, Baeksuk Chu","doi":"10.7736/jkspe.023.017","DOIUrl":"https://doi.org/10.7736/jkspe.023.017","url":null,"abstract":"","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135255259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
weights of requirements for a given part. Fuzzy TOPSIS was employed for determining ranks of candidate processes based on weights of requirements and evaluation of processes. Fuzzy logic was applied to handle ambiguous and inaccurate information encountered in evaluating the relative importance of requirements and performances of processes. The case study in which the optimal process for micro-hole drilling of a fuel injection nozzle was determined showed that the proposed method was effective. It could be extended to micromachining of various shapes
{"title":"Multi-criteria Decision Making of the Optimal Micromachining Process Using Fuzzy AHP-TOPSIS","authors":"Seong-Gu Kang, Jihong Hwang","doi":"10.7736/jkspe.023.021","DOIUrl":"https://doi.org/10.7736/jkspe.023.021","url":null,"abstract":"weights of requirements for a given part. Fuzzy TOPSIS was employed for determining ranks of candidate processes based on weights of requirements and evaluation of processes. Fuzzy logic was applied to handle ambiguous and inaccurate information encountered in evaluating the relative importance of requirements and performances of processes. The case study in which the optimal process for micro-hole drilling of a fuel injection nozzle was determined showed that the proposed method was effective. It could be extended to micromachining of various shapes","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43760612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When laparoscopic surgery is performed, polymer clip blood vessel ligators are widely used to prevent bleeding and secure surgical vision. However, long-term use of such ligators can cause many structural problems, especially in the jaw part where the clip is mounted directly to the blood vessel. For example, jaws of the ligation device might be opened above the design value and upper and lower jaws might be twisted against each other. In addition, buckling or bending deformation can easily occur at the tip of the inner shaft. Due to these problems, the ligation machine cannot ligate the clip properly, which might lead to a medical accident. Therefore, in this study, the design was changed to improve these problems by increasing the pin diameter and contact surface, applying a double pin structure, and changing the structure of the shaft tip. As a result, the modified model showed 12.5% and 10.2% improvements in opening and twisting stiffness compared to the initial model with 7.2% and 58% improvements in critical buckling load and bending stiffness, respectively.
{"title":"A Study on the Structural Improvement of Ligation Parts of a Polymer Clip Blood Vessel Ligator","authors":"Sung-ho Han, Boklok Choi","doi":"10.7736/jkspe.023.027","DOIUrl":"https://doi.org/10.7736/jkspe.023.027","url":null,"abstract":"When laparoscopic surgery is performed, polymer clip blood vessel ligators are widely used to prevent bleeding and secure surgical vision. However, long-term use of such ligators can cause many structural problems, especially in the jaw part where the clip is mounted directly to the blood vessel. For example, jaws of the ligation device might be opened above the design value and upper and lower jaws might be twisted against each other. In addition, buckling or bending deformation can easily occur at the tip of the inner shaft. Due to these problems, the ligation machine cannot ligate the clip properly, which might lead to a medical accident. Therefore, in this study, the design was changed to improve these problems by increasing the pin diameter and contact surface, applying a double pin structure, and changing the structure of the shaft tip. As a result, the modified model showed 12.5% and 10.2% improvements in opening and twisting stiffness compared to the initial model with 7.2% and 58% improvements in critical buckling load and bending stiffness, respectively.","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47073558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sang-Hoon Lee, Seung‐Min Oh, S. Park, Seok Kim, Y. Cho
, a lattice structure was inserted into the tablet and the dissolution rate was compared. The tablet proposed in this study can be manufactured by the FDM method, adopting a lattice structure with a large surface area-to-volume ratio. Tablets containing various lattice structures were fabricated using water-soluble PVA filaments and dissolution experiments were conducted in water at 37 o C. As a result, it was confirmed that the specific surface area and the mass loss rate were proportional to both the 3D lattice structure and the monolith structure. Among different structures, the diamond structure had the most active dissolution
{"title":"A Study on the Dissolution Characteristics of 3D Printed Tablet with Lattice Structures","authors":"Sang-Hoon Lee, Seung‐Min Oh, S. Park, Seok Kim, Y. Cho","doi":"10.7736/jkspe.023.002","DOIUrl":"https://doi.org/10.7736/jkspe.023.002","url":null,"abstract":", a lattice structure was inserted into the tablet and the dissolution rate was compared. The tablet proposed in this study can be manufactured by the FDM method, adopting a lattice structure with a large surface area-to-volume ratio. Tablets containing various lattice structures were fabricated using water-soluble PVA filaments and dissolution experiments were conducted in water at 37 o C. As a result, it was confirmed that the specific surface area and the mass loss rate were proportional to both the 3D lattice structure and the monolith structure. Among different structures, the diamond structure had the most active dissolution","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43068355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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