Recently, with the expansion of application of polymer composite materials, high levels of deformation compensation actions have been developed. However, there is a problem of high-temperature viscoelasticity that occurs over time after completing the injection molding process. In this study, changes of mechanical properties of the Moldflow program for injection molding were analyzed to verify the viscoelasticity phenomenon through deformation analysis. In addition, deformation analysis of plastic injection molded products according to arrangement of three ribs was conducted and two products with different geometric shapes of the same function were compared. As a result, it was possible to reflect the viscoelastic effect by reducing the elastic modulus and shear modulus of the material. It was confirmed that the geometric shape with thick ribs formed in multiple longitudinal directions was mainly responsible. On the surface of the product where the rib arrangement was parallel and perpendicular to the flow direction, the orientation was orthogonal to the linear direction and the maximum residual stress was 81.17 MPa, which showed the largest value. It was judged that viscoelastic phenomena could be predicted and that an arrangement of parallel and perpendicular ribs that might intersect should be avoided.
{"title":"A Study on Creep Phenomenon after the Releasing of Injection Molded Articles","authors":"Yu-Jung Kim, H. Bang","doi":"10.7736/jkspe.023.011","DOIUrl":"https://doi.org/10.7736/jkspe.023.011","url":null,"abstract":"Recently, with the expansion of application of polymer composite materials, high levels of deformation compensation actions have been developed. However, there is a problem of high-temperature viscoelasticity that occurs over time after completing the injection molding process. In this study, changes of mechanical properties of the Moldflow program for injection molding were analyzed to verify the viscoelasticity phenomenon through deformation analysis. In addition, deformation analysis of plastic injection molded products according to arrangement of three ribs was conducted and two products with different geometric shapes of the same function were compared. As a result, it was possible to reflect the viscoelastic effect by reducing the elastic modulus and shear modulus of the material. It was confirmed that the geometric shape with thick ribs formed in multiple longitudinal directions was mainly responsible. On the surface of the product where the rib arrangement was parallel and perpendicular to the flow direction, the orientation was orthogonal to the linear direction and the maximum residual stress was 81.17 MPa, which showed the largest value. It was judged that viscoelastic phenomena could be predicted and that an arrangement of parallel and perpendicular ribs that might intersect should be avoided.","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":"45536149","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":"Design, Fabrication, and Control of a Rotary Manipulator driven by Twisted Shape Memory Alloy (SMA) Wires","authors":"Gil‐Yong Lee, Suyeon Lee","doi":"10.7736/jkspe.023.039","DOIUrl":"https://doi.org/10.7736/jkspe.023.039","url":null,"abstract":"","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":"48094555","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}
H. Park, Jeong-Won Lee, Seongmin Kim, Kihwan Kim, Y. Kim, W. Hwang
), Depth filter ( 심층 필터 ), Plasma treatment ( 플라즈마 처리 ), Dip coating ( 딥 코팅 ), Oil–water separation ( 유수분리 ) Purification of water through oil–water separation is essential for preserving the ecosystem and protecting human health. Although a conventional polypropylene depth filter can effectively purify water, modifying the wettability of a filter for oil–water separation is difficult owing to its low reactivity. In this study, we developed a superhydrophilic polypropylene filter with a hydrogel layer that could enable effective oil–water separation by using plasma treatment and dip coating, which enabled an even distribution of the coating solution across the filter. The fabricated filter was superhydrophilic with a water contact angle of 0 o . It showed a high repulsive force with oil in water with an underwater oil contact angle of 142.9 o . When such filter was applied to an oil–water separation device, it effectively purified water with low oil content (< 15 ppm) at a flow rate of 300 mL/ min. These results demonstrate potential applications of such filters in areas such as wastewater treatment and oil spill cleanup.
{"title":"Superhydrophilic Modification of a Polypropylene Depth Filter for Efficient Oil–water Separation","authors":"H. Park, Jeong-Won Lee, Seongmin Kim, Kihwan Kim, Y. Kim, W. Hwang","doi":"10.7736/jkspe.023.032","DOIUrl":"https://doi.org/10.7736/jkspe.023.032","url":null,"abstract":"), Depth filter ( 심층 필터 ), Plasma treatment ( 플라즈마 처리 ), Dip coating ( 딥 코팅 ), Oil–water separation ( 유수분리 ) Purification of water through oil–water separation is essential for preserving the ecosystem and protecting human health. Although a conventional polypropylene depth filter can effectively purify water, modifying the wettability of a filter for oil–water separation is difficult owing to its low reactivity. In this study, we developed a superhydrophilic polypropylene filter with a hydrogel layer that could enable effective oil–water separation by using plasma treatment and dip coating, which enabled an even distribution of the coating solution across the filter. The fabricated filter was superhydrophilic with a water contact angle of 0 o . It showed a high repulsive force with oil in water with an underwater oil contact angle of 142.9 o . When such filter was applied to an oil–water separation device, it effectively purified water with low oil content (< 15 ppm) at a flow rate of 300 mL/ min. These results demonstrate potential applications of such filters in areas such as wastewater treatment and oil spill cleanup.","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":"47163761","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":"Heat Reduction Characteristics of Wear Ring with Umbrella-type Micro-dimple","authors":"Young-Chan Yoon, Taek-Sung Lee","doi":"10.7736/jkspe.023.040","DOIUrl":"https://doi.org/10.7736/jkspe.023.040","url":null,"abstract":"","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":"42529477","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":"Study on Effect of Ultrasonic Nanocrystal Surface Modification in Bolt Manufactured by Screw Rolling","authors":"Hyeong-Jin Ha, Hana Park, Tae-Hyung Jung, D. Shim","doi":"10.7736/jkspe.023.023","DOIUrl":"https://doi.org/10.7736/jkspe.023.023","url":null,"abstract":"","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":"49225336","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}
attention in biomechanics. Generally, the joint force and moment are calculated though inverse dynamics using segment kinematic data, ground reaction force
生物力学关注。通常，关节力和力矩是通过使用分段运动学数据的逆动力学计算的，地面反作用力
{"title":"Wearable Inertial Sensors-based Joint Kinetics Estimation of Lower Extremity Using a Recurrent Neural Network","authors":"J. Choi, Chan Lee, Jung-Keun Lee","doi":"10.7736/jkspe.023.042","DOIUrl":"https://doi.org/10.7736/jkspe.023.042","url":null,"abstract":"attention in biomechanics. Generally, the joint force and moment are calculated though inverse dynamics using segment kinematic data, ground reaction force","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":"47945410","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}
is likely to occur before the end of its designated lifespan. This study aims to examine the possibility of extending the component's lifespan by evaluating the remaining useful life of L-holder, a part of CSU, that has been in use for 20 years. Fatigue load history was predicted by measuring the strain with or without strain at the L-holder part requiring periodic replacement. Through tensile and fatigue tests, the remaining life was evaluated when cracks were not present. In addition, the remaining life in the presence of cracks was evaluated through destructive toughness test and fatigue crack propagation test. Life prediction results based on test cycles were obtained. The proposed guidelines are expected to be helpful for preventing CSU accidents
{"title":"Prediction of the Remaining Useful Life of L-holder for Continuous Ship Unloader","authors":"Seung-Hun Lee, Dong‐Woo Lee, Jung‐il Song","doi":"10.7736/jkspe.023.015","DOIUrl":"https://doi.org/10.7736/jkspe.023.015","url":null,"abstract":"is likely to occur before the end of its designated lifespan. This study aims to examine the possibility of extending the component's lifespan by evaluating the remaining useful life of L-holder, a part of CSU, that has been in use for 20 years. Fatigue load history was predicted by measuring the strain with or without strain at the L-holder part requiring periodic replacement. Through tensile and fatigue tests, the remaining life was evaluated when cracks were not present. In addition, the remaining life in the presence of cracks was evaluated through destructive toughness test and fatigue crack propagation test. Life prediction results based on test cycles were obtained. The proposed guidelines are expected to be helpful for preventing CSU accidents","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":"45240787","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}
Tae-Hee Kim, Ha-Eun Jo, Hui-Woo Choi, Pyoung-Hwa Choi, Won-jae Lee, Heegoo Yang, W. S. Sim
IMU) signals and clinical evaluation scales for Parkinson's disease were correlated. The study included 16 patients diagnosed with Parkinson's disease. Each subject was evaluated based on Korean Mini-Mental State Examination (KMMSE), Unified Parkinson's Disease Rating Scale (UPDRS) part 3, New Freezing of Gait Questionnaire (NFOGQ) parts 2 & 3, and Hoehn & Yahr Scale (H&Y). All subjects performed the Time Up and Go test by attaching IMU sensors to both ankles and torso. Based on the tilting angle of torso and the time of first step, the freezing and non-freezing windows were determined. Seven IMU features involving the ankle signals were calculated in the specific window. Spearman’s correlation analysis of clinical evaluation scales was performed. As a result, the freezing index and power of locomotion band (0.3-3 Hz) were recommended to determine UPDRS part 3. Also, the intensity of the locomotion band facilitated evaluation of NFOGQ part 3 regardless of freezing of gait.
IMU）信号与帕金森病的临床评估量表之间存在相关性。这项研究包括16名被诊断为帕金森氏症的患者。根据韩国小型精神状态检查（KMMSE）、统一帕金森病评定量表（UPDRS）第3部分、新步态冻结问卷（NFOGQ）第2和第3部分以及Hoehn&Yahr量表（H&Y）对每个受试者进行评估。所有受试者通过将IMU传感器连接到脚踝和躯干来进行Time Up and Go测试。根据躯干的倾斜角度和第一步的时间，确定了冷冻和非冷冻窗口。在特定窗口中计算了涉及脚踝信号的七个IMU特征。对临床评价量表进行Spearman相关性分析。因此，推荐冻结指数和运动频带（0.3-3Hz）的功率来确定UPDRS第3部分。此外，运动带的强度有助于评估NFOGQ第3部分，而不考虑步态的冻结。
{"title":"Correlation Analysis between Clinical Rating Scales and Inertial Signal Features in Parkinson’s Disease Patients","authors":"Tae-Hee Kim, Ha-Eun Jo, Hui-Woo Choi, Pyoung-Hwa Choi, Won-jae Lee, Heegoo Yang, W. S. Sim","doi":"10.7736/jkspe.022.149","DOIUrl":"https://doi.org/10.7736/jkspe.022.149","url":null,"abstract":"IMU) signals and clinical evaluation scales for Parkinson's disease were correlated. The study included 16 patients diagnosed with Parkinson's disease. Each subject was evaluated based on Korean Mini-Mental State Examination (KMMSE), Unified Parkinson's Disease Rating Scale (UPDRS) part 3, New Freezing of Gait Questionnaire (NFOGQ) parts 2 & 3, and Hoehn & Yahr Scale (H&Y). All subjects performed the Time Up and Go test by attaching IMU sensors to both ankles and torso. Based on the tilting angle of torso and the time of first step, the freezing and non-freezing windows were determined. Seven IMU features involving the ankle signals were calculated in the specific window. Spearman’s correlation analysis of clinical evaluation scales was performed. As a result, the freezing index and power of locomotion band (0.3-3 Hz) were recommended to determine UPDRS part 3. Also, the intensity of the locomotion band facilitated evaluation of NFOGQ part 3 regardless of freezing of gait.","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44859451","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}
H. Kim, Duk-Yeon Lee, D. Choi, Jaehyeon Kang, Dong-Wook Lee
surface it is inconvenient to analyze an entire image due to multiple defocused areas. The defocusing is usually caused by the small depth of the lens and the rough surface curve. Thus, these microscopic images in an oil painting have multiple focal points, which indicates multi-focus images. We present a multi-focus fusion synthesizing a focused image from scans based on focal direction and selection of focused places. Based on microscopic characteristics, a common scanned area of the images was defined to unify the lens multiplication. A focus index was applied to each pixel to identify well-focused pixels and generate a mapping image in the focal direction. Subsequently, a median filter was applied to the mapping image and a multifocal image was acquired based on actual pixel values obtained from the mapping image. The proposed method was utilized in analyzing oil painting samples carrying rough surface curves. The multifocal image facilitated the analysis of the oil painting surface and resulted in enhanced quality compared with other methods. The proposed method can be used to generate useful images in scientific and industrial microscopy
{"title":"A Study on the Multi-focus Method of Microscopic Images for Oil-painting Analysis","authors":"H. Kim, Duk-Yeon Lee, D. Choi, Jaehyeon Kang, Dong-Wook Lee","doi":"10.7736/jkspe.022.151","DOIUrl":"https://doi.org/10.7736/jkspe.022.151","url":null,"abstract":"surface it is inconvenient to analyze an entire image due to multiple defocused areas. The defocusing is usually caused by the small depth of the lens and the rough surface curve. Thus, these microscopic images in an oil painting have multiple focal points, which indicates multi-focus images. We present a multi-focus fusion synthesizing a focused image from scans based on focal direction and selection of focused places. Based on microscopic characteristics, a common scanned area of the images was defined to unify the lens multiplication. A focus index was applied to each pixel to identify well-focused pixels and generate a mapping image in the focal direction. Subsequently, a median filter was applied to the mapping image and a multifocal image was acquired based on actual pixel values obtained from the mapping image. The proposed method was utilized in analyzing oil painting samples carrying rough surface curves. The multifocal image facilitated the analysis of the oil painting surface and resulted in enhanced quality compared with other methods. The proposed method can be used to generate useful images in scientific and industrial microscopy","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45142685","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":"Analysis of the Possibility of Classifying Field Hockey Positions Using Random-forest","authors":"Ji-Eung Kim, Seung-Hun Lee, Hoi-deok Jeong","doi":"10.7736/jkspe.023.055","DOIUrl":"https://doi.org/10.7736/jkspe.023.055","url":null,"abstract":"","PeriodicalId":37663,"journal":{"name":"Journal of the Korean Society for Precision Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44862911","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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