• Title/Summary/Keyword: Wear model

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Study on transient performance of tilting-pad thrust bearings in nuclear pump considering fluid-structure interaction

  • Qiang Li;Bin Li;Xiuwei Li;Quntao Xie;Qinglei Liu;Weiwei Xu
    • Nuclear Engineering and Technology
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    • v.55 no.6
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    • pp.2325-2334
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    • 2023
  • To study the lubrication performance of tilting-pad thrust bearing (TPTBs) during start-up in nuclear pump, a hydrodynamic lubrication model of TPTBs was established based on the computational fluid dynamics (CFD) method and the fluid-structure interaction (FSI) technique. Further, a mesh motion algorithm for the transient calculation of thrust bearings was developed based on the user defined function (UDF). The result demonstrated that minimum film thickness increases first and then decreases with the rotational speed under start-up condition. The influence of pad tilt on minimum film thickness is greater than that of collar movement at low speed, and the establishment of dynamic pressure mainly depends on pad tilt and minimum film thickness increases. As the increase of rotational speed, the influence of pad tilt was abated, where the influence of the moving of the collar dominated gradually, and minimum film thickness decreases. For TPTBs, the circumferential angle of the pad is always greater than the radial angle. When the rotational speed is constant, the change rate of radial angle is greater than that of circumferential angle with the increase of loading forces. This study can provide reference for improving bearing wear resistance.

Development of 3D-printed Cultural Products Using Yuan Blue and White Porcelain Patterns

  • Bowei Hu;Sun Young Choi
    • Journal of the Korean Society of Clothing and Textiles
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    • v.48 no.3
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    • pp.576-595
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    • 2024
  • Bracelets have enjoyed extensive use among the Chinese since antiquity as decorative pieces credited with warding off evil forces and inviting auspicious fortune. This study aims to integrate traditional cultural elements, such as Yuan blue and white porcelain flower patterns, into modern design using 3D printing technology to create culturally inspired bracelets. To this end, bracelet designs from the top four museums on Taobao were examined. In addition, we analyzed online reviews of culturally themed bracelets using text mining and applying FEA criteria and found that Chinese consumers are easy to wear and sizable, enhance cultural pride, and drive the demand for artistically sophisticated bracelets. The research culminates in the development of a modular bracelet design inspired by flower motifs from blue and white ware of the Yuan dynasty, with an emphasis on iterative improvements based on reviewer feedback. The final design meets consumers' expressive and aesthetic needs while also maintaining cultural integrity and functionality. The aim of the study is to inspire pride in traditional culture, provide insights for fashion accessory industries, and promote the national image through the development of culturally inspired products.

Scene Generation of CNC Tools Utilizing Instant NGP and Rendering Performance Evaluation (Instant NGP를 활용한 CNC Tool의 장면 생성 및 렌더링 성능 평가)

  • Taeyeong Jung;Youngjun Yoo
    • IEMEK Journal of Embedded Systems and Applications
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    • v.19 no.2
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    • pp.83-90
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    • 2024
  • CNC tools contribute to the production of high-precision and consistent results. However, employing damaged CNC tools or utilizing compromised numerical control can lead to significant issues, including equipment damage, overheating, and system-wide errors. Typically, the assessment of external damage to CNC tools involves capturing a single viewpoint through a camera to evaluate tool wear. This study aims to enhance existing methods by using only a single manually focused Microscope camera to enable comprehensive external analysis from multiple perspectives. Applying the NeRF (Neural Radiance Fields) algorithm to images captured with a single manual focus microscope camera, we construct a 3D rendering system. Through this system, it is possible to generate scenes of areas that cannot be captured even with a fixed camera setup, thereby assisting in the analysis of exterior features. However, the NeRF model requires considerable training time, ranging from several hours to over two days. To overcome these limitations of NeRF, various subsequent models have been developed. Therefore, this study aims to compare and apply the performance of Instant NGP, Mip-NeRF, and DS-NeRF, which have garnered attention following NeRF.

A Fully Digital Auricular Splint Workflow for Post-Keloid Excision

  • Rahmat Maria;Yee Onn Kok;Khim Hean Teoh
    • Archives of Plastic Surgery
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    • v.50 no.6
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    • pp.563-567
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    • 2023
  • Ear keloids are challenging lesions to treat due to high recurrence rates postexcision. Conservative compression techniques as adjunct treatment have been reported to be effective. An innovative technique of using computer-aided design/computed-aided manufacturing to print a customized auricular splint improves efficiency and comfort level for patients compared with conventional methods. The ear is scanned using an intraoral scanning 2 weeks postsurgery. A two-piece auricular splint is designed on the digital model, incorporating perforated projections for three nylon screws for retention of the splint. The splint is printed with clear acrylic material, postprocessed, and finished. The patient is taught to assemble the components of the splint and instructed to wear for at least 8 hours daily. The surgery site reviewed for any ulceration, pain, or recurrence of keloid for 6 months. During the 6-month review, the excision scar remained flat and pink. The patient also reports unrestricted daily activities. The digital workflow increases comfort for the patient and reduces the number of hours required to produce a customized auricular splint compared with conventional methods. A fully digital workflow for a printed auricular splint should be considered for adjunctive treatment to excision of ear keloids.

Development and Effectiveness Evaluation of Teaching/Learning Plan for Clothing Safety Education in Home Economics Based on the Health Belief Model (건강신념모델을 적용한 의생활 안전교육 교수·학습 과정안 개발 및 효과평가)

  • Kim, Ryu-Gyeong;Shim, Huen-Sup
    • Journal of Korean Home Economics Education Association
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    • v.32 no.1
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    • pp.127-143
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    • 2020
  • The purpose of this study is to develop the clothing safety teaching/learning plan in Home Economics based on the health belief model and to examine the effects of the course using the developed teaching/learning plan on the health belief. Based on ADDIE model, 6 clothing safety teaching/learning plans were developed by applying the health belief model. They consisted of three learning factors of 'harmful substances that can be exposed during the production, wear, wash, and storage of clothes and textile products', 'environment friendly fibers' and 'natural detergents'. Then they were implemented on 7 classes in middle school located in Gyeonggi-do Province from August 20 to September 7 in 2018. The health beliefs data collected before and after the course were analyzed with paired t-test with SPSS/win. As a result, the perceived threat(combination of perceived severity and perceived susceptibility), the perceived benefit, and the self-efficacy were significantly improved. And the perceived barrier was significantly reduced. In conclusion, the home economics clothing safety education course using the health belief model was meaningful as the safety education to enable middle school students to practice safe clothing life from harmful substances. The results of this study are expected to be helpful for activating safety education in home economics.

The Effect of Attributes of Innovation and Perceived Risk on Product Attitudes and Intention to Adopt Smart Wear (스마트 의류의 혁신속성과 지각된 위험이 제품 태도 및 수용의도에 미치는 영향)

  • Ko, Eun-Ju;Sung, Hee-Won;Yoon, Hye-Rim
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.2
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    • pp.89-111
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    • 2008
  • Due to the development of digital technology, studies regarding smart wear integrating daily life have rapidly increased. However, consumer research about perception and attitude toward smart clothing hardly could find. The purpose of this study was to identify innovative characteristics and perceived risk of smart clothing and to analyze the influences of theses factors on product attitudes and intention to adopt. Specifically, five hypotheses were established. H1: Perceived attributes of smart clothing except for complexity would have positive relations to product attitude or purchase intention, while complexity would be opposite. H2: Product attitude would have positive relation to purchase intention. H3: Product attitude would have a mediating effect between perceived attributes and purchase intention. H4: Perceived risks of smart clothing would have negative relations to perceived attributes except for complexity, and positive relations to complexity. H5: Product attitude would have a mediating effect between perceived risks and purchase intention. A self-administered questionnaire was developed based on previous studies. After pretest, the data were collected during September, 2006, from university students in Korea who were relatively sensitive to innovative products. A total of 300 final useful questionnaire were analyzed by SPSS 13.0 program. About 60.3% were male with the mean age of 21.3 years old. About 59.3% reported that they were aware of smart clothing, but only 9 respondents purchased it. The mean of attitudes toward smart clothing and purchase intention was 2.96 (SD=.56) and 2.63 (SD=.65) respectively. Factor analysis using principal components with varimax rotation was conducted to identify perceived attribute and perceived risk dimensions. Perceived attributes of smart wear were categorized into relative advantage (including compatibility), observability (including triability), and complexity. Perceived risks were identified into physical/performance risk, social psychological risk, time loss risk, and economic risk. Regression analysis was conducted to test five hypotheses. Relative advantage and observability were significant predictors of product attitude (adj $R^2$=.223) and purchase intention (adj $R^2$=.221). Complexity showed negative influence on product attitude. Product attitude presented significant relation to purchase intention (adj $R^2$=.692) and partial mediating effect between perceived attributes and purchase intention (adj $R^2$=.698). Therefore hypothesis one to three were accepted. In order to test hypothesis four, four dimensions of perceived risk and demographic variables (age, gender, monthly household income, awareness of smart clothing, and purchase experience) were entered as independent variables in the regression models. Social psychological risk, economic risk, and gender (female) were significant to predict relative advantage (adj $R^2$=.276). When perceived observability was a dependent variable, social psychological risk, time loss risk, physical/performance risk, and age (younger) were significant in order (adj $R^2$=.144). However, physical/performance risk was positively related to observability. The more Koreans seemed to be observable of smart clothing, the more increased the probability of physical harm or performance problems received. Complexity was predicted by product awareness, social psychological risk, economic risk, and purchase experience in order (adj $R^2$=.114). Product awareness was negatively related to complexity, meaning high level of product awareness would reduce complexity of smart clothing. However, purchase experience presented positive relation with complexity. It appears that consumers can perceive high level of complexity when they are actually consuming smart clothing in real life. Risk variables were positively related with complexity. That is, in order to decrease complexity, it is also necessary to consider minimizing anxiety factors about social psychological wound or loss of money. Thus, hypothesis 4 was partially accepted. Finally, in testing hypothesis 5, social psychological risk and economic risk were significant predictors for product attitude (adj $R^2$=.122) and purchase intention (adj $R^2$=.099) respectively. When attitude variable was included with risk variables as independent variables in the regression model to predict purchase intention, only attitude variable was significant (adj $R^2$=.691). Thus attitude variable presented full mediating effect between perceived risks and purchase intention, and hypothesis 5 was accepted. Findings would provide guidelines for fashion and electronic businesses who aim to create and strengthen positive attitude toward smart clothing. Marketers need to consider not only functional feature of smart clothing, but also practical and aesthetic attributes, since appropriateness for social norm or self image would reduce uncertainty of psychological or social risk, which increase relative advantage of smart clothing. Actually social psychological risk was significantly associated to relative advantage. Economic risk is negatively associated with product attitudes as well as purchase intention, suggesting that smart-wear developers have to reflect on price ranges of potential adopters. It will be effective to utilize the findings associated with complexity when marketers in US plan communication strategy.

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Repetitive Dorsiflexion Exercises in Ankles have Effects on the Active Range of Flexion and Extension Motion through Lumbar, Cervical Spine and Ankle, Wrist Joints (족관절의 반복적 배측굴곡 운동이 요.경추와 족.수관절의 능동 굴신 가동범위에 미치는 영향)

  • Moon, Sang-Eun;An, Sung-Jun;Jung, Dong-Sub
    • Journal of Korean Physical Therapy Science
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    • v.15 no.4
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    • pp.27-34
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    • 2008
  • Background: This study was designed to analyze Repetitive dorsiflexion exercises in ankles have effects on the active range of flexion and extension motion through lumbar, cervical spine and ankle, wrist joints. Methods: 30 female college students in their twenties who frequently wear high heels participated the number of the experimental group was 15 persons and the number of the control group was 15 persons. They did exercise at the physical therapy room in M college, from the 8th of March to the 11th of April 2007. The experimental group had used the model of dorsiflexion repetitive exercise three times per week, for 4 weeks, but the control group did not exercise at all. In the sagittal plane active ROM of the these spine and joints were measured before and after the experiment using a digital goniometer. The results of two groups were compared and analyzed using paired T-test. Results: The active range of flexion and extension motion of the vertebra(especially lumbar flexion) and distal joints were significantly different in exercise group(p<.05). Conclusion: The model of repetitive dorsiflexion exercise of the ankle joint had positive effects on improving the active range of flexion and extension motion of the lumbar vertebra and distal joints of limbs. The results suggest that the repetitive dorsiflexion exercise is useful and also effective therapy for improving motion in women usually wearing high-heel.

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Feedrate Optimization Using CL Surface (공구경로 곡면을 이용한 이송속도 최적화)

  • 김수진;정태성;양민양
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.4
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    • pp.39-47
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    • 2004
  • In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR(material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over loom, so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL (cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants were applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to the machining of speaker and cellular phone mold. The finishing time was reduced to 12.6%, tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were reduced, compared to the machining by constant feedrate. The machining time was shorter to 17% and surface quality and tool was also better than the conventional federate regulation using curvature of the tool path.

An Analysis about the Behavior of the Wiper Blade Including Incompressibility (비압축성을 고려한 와이퍼 블레이드의 거동 해석)

  • Chung, Won-Sun;Song, Hyun-Seok;Park, Tae-Won;Jung, Sung-Pil;Kim, Wook-Hyeon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.83-90
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    • 2010
  • The windshield wiper consists of 4 parts: a blade, an arm, a linkage and a motor. The wiper blade makes contact with the windshield and is designed to be operated normally at an angle of 30~50 degrees to the front glass. If the contact pressure between the wiper blade and windshield surface is too high, noise and wear of the rubber will result. On the other hand, if the contact pressure is too low, the performance will do badly, since foreign substances such as dust and stains will not be removed well. The pressure and friction of the wiper blade has a great influence on its effectiveness in cleaning the front window. This is due to the contact of the rubber with the window. This paper presents the dynamic analysis method to estimate the performance of the flat type blade of the wiper system. The blade has a nonlinear characteristic since the rubber is an incompressible hyper-elastic and visco-elastic material. Thus, Structural dynamic analysis using a complex contact model for the blade is performed to find the characteristics of the blade. The flexible multi-body dynamic model is verified by the comparison between test and analysis result. Also, the optimization using the central composite design table is performed.

A Study on the Registration of Patent and Utility Models by Fashion Firms in Korea -Focus on IPC A41B and A41D- (패션기업의 특허.실용신안 등록현황에 관한 연구 -IPC분류코드 A41B와 A41D를 중심으로-)

  • Kim, Yong-Ju
    • Journal of the Korean Society of Clothing and Textiles
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    • v.35 no.2
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    • pp.192-205
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    • 2011
  • This study analyzed the registration of patent and utility models by fashion firms in Korea. A total of 2,291 registration cases of IPC A41B-H from the period of 1996 to 2009 were collected by KIPRIS of the Korean Intellectual Property Organization (KIPO). All cases were analyzed by year to review the longitudinal trend and 481 cases of IPC A41B (shirts, underwear, baby linen, and handkerchiefs) and 1088 cases of IPC A41D (outerwear, protective garments, and accessories) were analyzed by content (provided benefit type and developing method), by detailed product items and the characteristics of the applicant. The results of this study were as follows: 1) Registration of IPC 41 increased steeply by the year (especially since 2006) and the patent registrations increased more than those in the utility model. 2) Analyzing the application content of A41B on the basis of benefit showed that 75% were to provide new functions and the rest were for health. In terms of the developing method, 83% of benefit provided by the application were by design development, 11.2% were by material, and the rest was by process, In the cases of IPC A41D, 23.6% were for safety and protection. In terms of the developing method, the process and material development were more frequently adopted than in the cases of A41B. 3) The major product types of A41B were socks, underwear, and infant wear, whereas gloves and parts of clothing were major items in A41D. 4) In terms of the characteristics of the applicant, registration by firms was greater for patents than for utility models and registration by foreigners increased in 2006 due to the complete opening of the retail market. 5) Fifteen universities registered for a total 57 cases and major applications were for IT related clothing or high-tech protective items.