Characteristic of slipping behaviour in vibratory wear of a supported tube

Kim, Hyung-Kyu,Lee, Young-Ho Elsevier 2005 Wear: An international journal on the science and Vol.259 No.1

<P><B>Abstract</B></P><P>Fretting wear of a vibratory tube is studied from the investigation of the slipping characteristics on the contacts between the tubes and the supports. The primary application of the present research is the tube bundle structures subjected to a flow-induced vibration in the nuclear power plant components. Tests were carried out to simulate the vibration of the fuel rods, in particular, those supported by springs and dimples. Two typical types of supports were used at both ends of the tube, which was forced to vibrate with 30Hz. The supporting condition was varied artificially: positive contact force or gap existence. During the tube vibration, the amplitudes were measured continuously in the vicinity of the supports. Simple equations were derived to evaluate the slip displacement on the contacts. Wear volume, area and the maximum depth of the wear scars on the tubes were investigated after 10<SUP>6</SUP> vibration cycles. As a result, it was found that the supporting condition affected the vibration characteristics near the contacts. In the positive contact condition, the phase difference of the vibration signals at both sides of the contact was 180°. It is altered in the gap condition and the multiple values of 30Hz were found from the fast Fourier transform analysis. The high frequency vibration is thought to cause the wear to become severer in the gap condition. The support with dimples revealed more wear. The influence of the contact shape on the wear was discussed from this. The relationship between the slip displacement and the wear was also discussed together with a new wear parameter.</P>

써클 및 동일 재질 콘택트렌즈의 임상 적용시 눈에 미치는 영향

박상희,김소라,박미정 한국안광학회 2011 한국안광학회지 Vol.16 No.2

Purpose: The present study was conducted to investigate the actual condition of circle lens wear and the differences caused by the pigmentation in blinking rate, non-invasive tear break-up time (NIBUT), and lens surface between circle and soft contact lens wear during clinical application. Methods: Eighty subjects were surveyed to know the actual condition of wearing circle lens. Blink rate, NIBUT of 20 subjects in twenties were measured after separately wearing soft contact lens and circle lens for 5 days. Their lens surfaces were also observed by scanning electron microscope. Results: Fifty percent of circle lens wearers answered that major reason for changing circle lens was discomfort and 67% of answerers wore circle lens more than 6 hours a day. The tendency of increased blink rates in both wearers of circle and soft contact lens at 30 minutes later when tear film stabilized and 3 hour after lens wearing was shown on the 1st, 3rd and 5th day with expanding wearing time. Especially at 3 hours after lens wearing on the 3rd and 5th day, the difference of blink rates was statistically different in circle lens wear and soft contact lens wear. The NIBUTs of soft contact lens wearers and circle lens wearers were 6.0 and 3.7 secs, respectively, at 30 min later on 1st day and were significantly different. NIBUTs of soft contact lens wearers and circle lens wearers were also statistically different 3 hrs after lens wearing on the 1st day and the similar pattern of NIBUTs was shown on the 3rd and 5th day. The roughness of both surfaces in soft contact lens and front surface in circle lens was same. However, pigmented front surface of circle lens was rougher and uneven. Conclusions: As the results, the circle lens wearers might feel discomfort in clinical application since the difference in lens surface of circle lens would change lens wettability during wearing. The difference by tinting contact lens was shown from the result, which could help better wearing circle lens. 목적: 본 연구에서는 써클 콘택트렌즈의 착용 실태를 조사하고, 임상 적용 시 동일재질의 일반 소프트 콘택트렌즈 착용 시의 순목횟수, 비침입성 눈물막 파괴시간 및 렌즈 표면의 차이를 비교하여 착색 여부에 따른 차이를 알아보 고자 하였다. 방법: 80명을 대상으로 써클 콘택트렌즈의 착용 실태를 알아보았으며, 20대 20안을 대상으로 하여 동 일한 재질 및 파라미터의 일반 소프트 콘택트렌즈와 써클 콘택트렌즈를 각각 5일 동안 착용시킨 후 순목 횟수, 비 침입성 눈물막 파괴시간을 측정하였다. 또한, 주사전자현미경을 이용하여 렌즈의 표면을 관찰하였다. 결과: 써클 콘 택트렌즈 교체의 주요 원인이 불편감이라고 답한 응답자가 50%에 달하였으며, 67%가 하루에 6시간 이상을 착용하 는 것으로 나타났다. 콘택트렌즈 착용 1일, 3일, 5일째에 눈물막이 안정화된 시점인 착용 30분 후와 3시간 후의 순 목 횟수는 두 종류의 렌즈 모두 착용 기간이 증가할수록 증가하는 경향을 보였다. 3일째, 5일째 착용 3시간 후에는 써클 콘택트렌즈 착용 시와 소프트 콘택트렌즈 착용 시의 순목 횟수가 통계적으로 유의한 차이가 나타났다. 콘택트 렌즈를 착용한 상태에서의 비침입성 눈물막 파괴시간은 착용 1일째 30분 후 소프트 콘택트렌즈 착용 시는 6.0 초, 써클 콘택트렌즈는 3.7 초로 통계적으로 유의한 차이가 있었다. 착용 3시간 후에도 두 렌즈 사이의 비침입성 눈물 막 파괴시간에는 통계적으로 유의한 차이가 있었으며, 착용 3일째와 5일째도 마찬가지였다. 써클 콘택트렌즈와 일 반 소프트 콘택트렌즈의 전후면과 써클 콘택트렌즈 후면의 표면조도(surface roughness)는 동일했으나 써클 콘택트 렌즈는 착색된 부분인 렌즈 전면부는 균일하지 않고 요철이 많았다. 결론: 써클 콘택트렌즈의 표면 차이가 렌즈 착 용 시 습윤성의 차이를 야기하였을 것으로 보이며 그로 인하여 불편감을 느끼게 되었을 것으로 생각되어졌다. 본 연구 결과로 착색으로 인한 써클 콘택트렌즈와 일반 소프트 콘택트렌즈의 차이를 밝혔으므로 건강한 써클 콘택트 렌즈의 착용에 도움이 될 수 있으리라 여겨진다.

국내 20, 30대 남성의 애슬레저웨어 착용실태조사

김은경 한국의상디자인학회 2024 한국의상디자인학회지 Vol.26 No.1

This study analyzes the athleisure wear purchase status, wearing conditions, and design preferences of men in their 20s and 30s and provides basic data for the development of men’s athleisure wear that reflects consumer preferences. An online survey was conducted on 200 men from August 23 to August 27, 2023. The questionnaire consisted of a total of 48 questions, including 8 questions about the respondent’s general information, 19 questions about the purchase status of athleisure wear, 6 questions about the status of wearing athleisure wear, and 15 questions about athleisure wear design preferences. The survey results are as follows. The most common motive for exercise participation was ‘maintaining health.’ ‘Nike’ was the most preferred and purchased brand among athleisure wear brands, and the main place of purchase of athleisure wear was ‘Internet and mobile shopping malls’, reflecting the recent purchasing trend of the MZ generation. When purchasing athleisure wear, the most common selection criterion was ‘design’, followed by ‘fitting comfort’, ‘possibility to use as daily wear’, and ‘price’. The most common route to obtain purchase information was ‘Internet search’, and the ‘overall satisfaction’ with athleisure wear was found to be satisfactory with an average of 3.83. The most common reason for wearing athleisure wear was ‘because it is comfortable to do activities’, followed by ‘because it can be used as everyday wear’. Lastly, ‘black’, ‘short-sleeved t-shirt’, ‘short length’ sleeve, ‘round neckline’, ‘waist length’, and ‘relaxed loose fit’ were preferred for the top design, and ‘black’, ‘shorts’, ‘full elastic type’ waistband, ‘regular fit that fits the body well’ were preferred for the bottom design. 운동과 같은 스포츠 활동만을 위한 스포츠웨어에서 나아가 기능성과 실용성을 겸비한 동시에 세련된 디자인으로 제안된 애슬레저웨어는 다양한 일상 상황에서 활용이 가능한 패션스타일로 자리 잡고 있다. 이러한 추세는 남성 패션에도 이어져 애슬레저웨어의 남성 구매력이 20, 30대를 중심으로 한 MZ세대로 확대되고 있는 실정이나 디자인, 패턴 설계의 기초가 되는 남성 애슬레저웨어의 착용실태 및 구매실태 연구는 부족한 상황이다. 따라서 본 연구에서는 20, 30대 남성의 애슬레저웨어 착용 실태 및 구매실태를 조사하고, 애슬레저웨어 디자인 선호도를 분석하여 실용적이고 세련된 그리고 기능성이 향상된 20, 30대 남성 애슬레저웨어 개발을 위한 기초자료로 제공하고자 설문조사를 실시하였으며 그 결과는 다음과 같다. 첫째, 조사대상자의 주 운동 참여 횟수는 ‘주 2-3일’이 71명(35.5%), 운동경력은 ‘3년 이상’이 75명(37.5%), 주 참여 운동은 ‘헬스(PT)’가 133명(66.5%)으로 가장 많이 나타났으며 운동참여 동기는 75명(37.5%)이 ‘건강유지’라고 응답하여 팬데믹 이후 건강에 대한 관심이 증대되었을 것으로 보여 진다. 둘째, 애슬레저웨어 선호브랜드 및 구매브랜드 모두 ‘나이키’가 가장 많았고, 애슬레저웨어 주 구매 장소는 ‘인터넷, 모바일 쇼핑몰’(103명, 51.5%)이 가장 많은 비율을 차지하여 최근 MZ세대 구매 트렌드를 반영하였다. 애슬레저웨어 구매빈도는 20대는 ‘1-3개월 이내에 한번’이 32명(16.0%)으로 가장 많았고, 30대는 ‘6개월-1년 이내에 한번’이 35명(17.5%)으로 가장 많이 나타났다. 애슬레저웨어 구매 시 선택 기준은 ‘디자인’이 118명(59.0%)으로 가장 높은 비율로 나타났고, ‘착용감’이 116명(58.0%), ‘일상복으로 활용가능성’이 110명(55.0%), ‘가격’이 99명(49.5%)을 차지하여 20, 30대 남성의 경우 디자인, 착용감 뿐 아니라 일상복으로의 활용 및 가격 등 실용적이고 합리적인 소비에 관심이 높음을 알 수 있다.

연마상태가 다른 RGP렌즈의 일정기간 착용 시 렌즈착용자의 자각적 증상, 눈물막 안정 및 순목횟수 변화

박미정,김효겸,배준섭,박정주,김소라 한국안광학회 2014 한국안광학회지 Vol.19 No.1

The present study was conducted to investigate the effect of the physical properties of RGP lensinduced by lens polishing on the actual wearer's subjective comfort, the tear film break-up time and the blinkingrate as a follow-up study that revealed the relationship between the lens physical properties during lensmanufacturing and lens wearer's factors. Methods: RGP lenses made from the three different polishing conditions(25, 50 and 100 seconds) were applied on 28 eyes of 17 subjects, aged 20 to 29 years, without any knowndisease and surgical history in the eyes. While the subjects were asked to wear the RGP lenses longer than aweek, the questionnaire for the comfortability was administered everyday. Subjective and objective tear break-uptime and blinking rate of the wearers were further measured. Results: The wearer’s subjective comfortabilityshowed some difference in the type of discomfort and satisfaction score according to the polishing status whenwearing RGP lenses made from different polishing conditions longer than a week, and a bigger difference insatisfaction score induced by polishing condition was especially shown in experienced RGP lens wearer ratherthan un-experienced wearer. In the case of RGP lens wearer compared with the ones without the wearingexperience, as the wearing time increased subjective and objective tear break-up time were increased and theblinking rate was decreased. However, subjective and objective tear break-up time were tended to decrease witheven longer wearing time when wearing the RGP lens made from the polishment for 100 seconds. Conclusions:These results confirmed that the optimization of physical properties of the lens may not give the same effect onthe wearer's subjective and objective symptoms and other factors when actual wearing. From the results, it cansuggest that the success rate of RGP lens wear may be changed by physiological factors such as the stabilizationof wearer's tear film, comfortability and lens wearing experience when wearing RGP lens based on ‘Themanufacturing standard for soft contact lens/hard contact lens’ provided by Korea Food and Drug Administration. 본 연구는 RGP렌즈 제조 시 렌즈물성과 렌즈착용자 요인과의 관계를 밝힌 선행연구의 후속 연구로 RGP렌즈 연마로 유발된 렌즈물성의 차이가 일정기간 착용 후 착용자가 느끼는 주관적 착용감 및 눈물막 파괴시간, 순목횟수 등에 미치는 영향을 알아보고자 하였다. 방법: 안질환이나 안과적 수술경험이 없는 20대 17명(남자7명, 여자10명)의 28안에게 각기 다른 연마조건(25초, 50초 및 100초)으로 제조된 3 종류의 렌즈를 각각 1주일 이상 착용하게 하였으며 매일 설문지를 통하여 착용 중의 착용감을 조사하였고, 자각적 및 타각적 눈물막 파괴시간과 순목횟수를 측정하였다. 결과: 연마조건이 다르게 제조된 RGP렌즈를 일주일 이상 착용하였을 때 렌즈 착용자의 주관적 착용감은 렌즈 별로 불편감의 종류나 착용감 점수에서 차이를 보였으며, 특히 RGP렌즈 착용 경험자의 경우는 RGP렌즈 착용 미경험자와 비교하여 연마조건에 따른 착용감 점수의 차이가 크게 나타나는 경향을 보였다. RGP렌즈 착용경험자의 경우 착용시간이 증가할수록 착용 미경험자에 비하여 렌즈에 더 잘 적응하는 양상을 보여 자각적 및 타각적 눈물막 파괴시간은 더욱 증가하는 경향을 보였으며, 순목횟수는 감소하는 경향을 보였다. 그러나 RGP렌즈 착용 경험 유무와는 관계없이 100초 연마렌즈 착용 시는 착용시간이 길어지더라도 자각적 및 타각적 눈물막 파괴시간은 감소하는 경향을 보였다. 결론: 이상의 결과로 렌즈물성의 최적화가 실제 착용 시에는 착용자의 자각적 및 타각적 증상에서도 동일한 효과를 내는 요인이 되지 못할 수도 있음을 확인하였다. 본 연구결과로부터 현재 식약처에서 제시하고 있는 ‘소프트콘택트렌즈/하드콘택트렌즈의 제조 기준규격’에 따라 제조된 RGP렌즈는 실제 착용 시 착용자의 눈물막 안정화나 착용감, 렌즈 착용 경험 유무와 같은 생리적 요인에 따라 착용성공률이 달라질 수 있음을 제안할 수 있다.

유압구동 부재의 마찰 상태 식별에 관한 연구

강인혁(I.H. Kang),류미라(M.R. Lyu),박재상(J.S. Park),박흥식(H.S. Park) 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.35 No.-

Analyzing working conditions with shape characteristics of wear debris in a lubricated machine, it can be effect on diagnosis of hydraulic machining system. And it can be recognized that results are processed threshold images of wear debris. But, in order to predict and estimate a working condition of lubricated machine, it is need to analysis a shape characteristic of wear debris and to identify. Therefor, If shape characteristics of wear debris are identified by computer image analysis and the neural network, it is possible to find the cause and effect of wear condition. In this study, wear debris in the lubricant oil are extracted by membrane filter (0.45 ㎛), and the quantitative value of shape characteristic of wear debris are calculated by the digital image processing. This morphological information are studied and identified by the artificial neural network. The purpose of this study is to apply morphological characteristic of wear debris to prediction and estimation of working condition in hydraulic machining systems.

프랜차이즈 커피전문점 유니폼의 착용실태와 개선요구도

김현정(Hyun Jeong Kim),배정혜(Jung Hye Bae),조은비(Eun Bi Cho),권수애(Soo Ae Kweon) 충북대학교 생활과학연구소 2016 생활과학연구논총 Vol.20 No.1

The purpose of this study is to grasp the discomfort of the actual operation of the functionality, suitability of activity and satisfaction of the fit and understanding improvement needs of the uniform who really wears. It has a purpose used of basic material for developing the uniform which consider the situation of the wearer. To collect sample and data collection we used survey. Survey target was people who works at 8kinds of franchise coffee shop and it has been enacted for 2weeks. Distribution quantity were 300 and actually used 160. Decide demographic characteristic, actual state of wearing variable we have used nominal scale for the Satisfaction, uncomfortable degree, improvement needs used Lickertis scale. For overall data analysis we Used SPSS Win Ver.21.0, for demographic characteristic used analysis of frequency and for Satisfaction, uncomfortable degree, improvement needs used descriptive statistic. As a result Of wear and management Uniform procurement methods are generally provided by headquarters and bear expenses. Summer and winter season wearing rates of shirt, pants, apron and hat are commonly used. Winter season wearing items are a lot and more variable then summer season. Washing method and period of uniforms, individuals are more hygienic then headquarter. Of the Satisfaction Character of fabric was the most important satisfaction factor in the second place were size and wear sensation factors. To increase wearing satisfaction fabric and size factor needs considering. Of the uncomfortable degree Searched about uncomfortable degree of body parts the result was we need improvements of hats for heads and to make arm feel comfortable. Of the Improvement requirements synthetically size fit, clothing of pollution, fabric function, ease of doing laundry needs improvements. For each item shirts needs most improvements, and cardigan was lowest.

신경회로망에 의한 유압구동 부재의 마찰계수 추정에 관한 연구

김동호 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.5

Wear debns can be collected from the lubricants of operating machinery and its morphology is directly related to the fiction condition of the interacting materials from which the wear particles originated in lubricated machinery. But, in order to predict and estimate working conditions. it is need to analyze the shape characteristics of wear debris and to identify. Therefor. if the shape characteristics of wear debns is identified by computer image analysis and the neural network The four parameter (50% volumetric diameter, aspect, roundness and reflectivity) of wear debris are used as inputs to the network and learned the friction. It is shown that identification results depend on the ranges of these shape parameters learned. The three kinds of the wear debns had a different patten characteristic and recognized the friction condition and materials very well by neural network. We resented how the neural network recognize wear debns on driving condition.

연구논문 : 자전거 의류 착용실태 조사

정희경 ( Hee Kyeong Jung ),이정란 ( Jeong Ran Lee ) 한국의류산업학회 2013 한국의류산업학회지 Vol.15 No.2

This study identifies how people use bicycle wear, complaints about bicycle wear, and functions required for bicycle riding. This survey was conducted with bicycle club members (men and women) in their twenties to sixties who ride bicycles on a regular basis. A total of 373 subjects responded to questionnaires and 326 responses were used for further data analysis. The data was analyzed by descriptive analysis, multiple response analysis, crosstabulation analysis, factor analysis, reliability analysis, and one-way ANOVA. The results are as follow: First, the people surveyed were primarily men, young adults and middle-aged people. They ride bicycles mainly to participate in club activities, to exercise, and to spend their spare time with a well-being trend that focuses on leisure and health. Second, they often utilize bicycle wear when they ride bicycles. They are aware of bicycle wear brands. In addition, a majority have purchased bicycle wear that shows a very high awareness of bicycle wear. Third, as for complaints about bicycle wear worn when riding bicycles, a majority of people answered that the waist part of the top pulls up and they feel sore with the bottom part of the pants when riding bicycles for a long time. They also answered that it is inconvenient to put belongings in both tops and pants. Fourth, there is a high demand for safety-related functions for bicycle riding in regards to the functions required for bicycle wear. In addition, a majority of the members showed a customer awareness of functional bicycle wear and intended to purchase bicycle wear equipped with smart functions.

연구논문 : 시니어 남성의 아웃도어 재킷착용실태 및 아웃도어 브랜드 제품치수조사

권정호 ( Jeongho Kwon ),정희경 ( Hee Kyeong Jung ),이정란 ( Jeong Ran Lee ) 한국의류산업학회 2015 한국의류산업학회지 Vol.17 No.4

This study analyzes the wearing and purchasing conditions of outdoor jackets by senior men who are over 50s, and examines product sizes of outdoor jackets in the market. A total of 134 questionnaires and sizing systems (or product size) of 10 outdoor brands were used as analytical data. The results were: a high number of senior men enjoyed hiking as an outdoor activity, with most of them following this activity1-3 times per month and as a preferred personal activity for over 5 years. Most needed outdoor wear suitable for these daily life activities. Outdoor wear satisfaction tends to decrease as people age. The major reason for the dissatisfaction with outdoor wear was price. Senior men aged 50s and 60s emphasize design and color when purchasing outdoor wear; however, men in their 70s considered price a priority. Senior men preferred outdoor brands based on a comfortable fit. An investigation on 10 outdoor brands indicated that they had not designated a specific target customer. A comparison of the product size of outdoor jackets with a similar silhouette indicated some deviations among sizes; however, the age of customers was not considered. The human body tends to shrink in stature and increase in girth as a person ages; consequently, we need to reflect body shape changes and senior``s size in outdoor wear.

파이어링 상태의 일정 축 각속도에서 엔진베어링의 마모 해석

전상명(Sang Myung Chun) 한국트라이볼로지학회 2018 한국윤활학회지(윤활학회지) Vol.34 No.4

This paper presents a wear analysis procedure for calculating the wear of journal bearings of a fourstrokes and four-cylinder engine operating at a constant angular crank shaft speed during firing conditions. To decide whether the lubrication state of a journal bearing is in the possible region of wear scar, we utilize the concept of the centerline average surface roughness to define the most oil film thickness scarring wear (MOFTSW) on two rough surfaces. The wear volume is calculated from the wear depth and wear angle, determined by the magnitude of each film thickness on a set of oil films with thicknesses lower than the MOFTSW at every crank angle. To calculate the wear volume at one contact, the wear range ratio during one cycle is used. The total wear volume is then determined by accumulating the wear volume at every contact. The fractional film defect coefficient, asperity load sharing factor, and modified specific wear rate for the application of the mixed-elasto-hydrodynamic lubrication regime are used. The results of this study show that wear occurs only at the connecting-rod big-end bearing. Thus, simulation results of only the big-end bearing are illustrated and analyzed. It is shown that the wear volume of each wear scar group occurs consecutively as the crank angle changes, resulting in the total accumulated wear volume.