• 상하수도학회지
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• 제30권4호
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• pp.417-425
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• 2016

Desalination is a key technology to overcome water shortage problem in a near future. High energy consumption is an Achilles' heel in desalination technology. Osmotically driven membrane processes like forward osmosis(FO) was introduced to address this energy issue. Characterizing membrane properties such as water permeability(A), salt permeability(B), and the resistance to salt diffusion within the support layer($K_{ICP}$) are very important to predict the performance of scaled-up FO processes. Currently, most of researches reported that the water permeability of FO membrane was measured by reverse osmosis(RO) type test. Permeating direction of RO and FO are different and RO test needs hydraulic pressure so that several problems can be occurred(i.e. membrane deformation, compaction and effect of concentration polarization). This study focuses on measuring water permeability of FO membrane by FO type test results in various experimental conditions. A statistical approach was developed to evaluate the three FO membrane properties(A, B, and $K_{ICP}$) and it predicted test result by the internal and external concentration polarization model.

• 한국운동역학회지
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• 제19권2호
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• pp.187-196
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• 2009

The foot type is classified into normal, high or low arch according to either foot print or medial longitudinal arch (MLA) height. Plantar fasciitis, heel pain, Achilles tendinitis, stress fracture, metatarsalgia, knee pain, shin splint pain, and etc are common foot disorders and associate to the foot type. The purpose of this study was to evaluate several suggested bony inclination used to classified the abnormal foot and if the arch index (AI) was correlated with foot morphology. Lateral view and dorso-plantar view of radiographic images and flatbed scanner measurements obtained from 57 college students were analyzed. Results showed that AI measured in this study was higher than Caucasian Americans and European, but similar with African. The ethnic origin could influent the AI distribution. The AI provided a simple quantitative means of assessing the structure of lateral and medial longitudinal arches. The correlation coefficients of true bone height with AI could be further improved by normalized foot width rather than foot length. AI also demonstrated as a good indicator of inclination between calcaneus-fifth metatarsal (CalM5) and calcaneus-first metatarsal (CalX), it is a good means to classify the foot type.

• 대한물리치료과학회지
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• 제15권3호
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• pp.55-63
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• 2008

Background : The Purposes of this study were to understand difference between free walking and obstacle over walking through the naked eye and motion analysis device, and to review merits of obstacle walking training as item of functional assessment in clinical situations. Methods : All participants were male and performed 3 types of walking methods: free walking, obstacle over walking with low block(height=10cm, width=8cm), and obstacle over walking with high block(height=20cm, width=8cm). All walking were performed 3 trials respectively. Results : In the naked eye, initial contact with toes occurred more than heel strike in obstacle over walking, and the flexion angle of hip and knee were increased in obstacle over walking. On interpretations though motion analysis device, cadence, gait speed and weight accept were significant statistically(p<.05). Cadence and gait speed were decreased, and weight accept duration was increased in obstacle over walking. Rotation among three pelvic motions was significant statistically(p<.05), flexion among three hip motions was significant statistically(p<.05) and flexion among three ankle motions was significant statistically(p<.05). Rotation and flexion among three ankle motions was significant statistically(p<.05). Conclusion : Both the naked eye and interpretations of the device presented many difference between free walking and obstacle over walking. In overcrossing obstacles, many participants appeared walking strategy by perform initial contact with toes. Knee flexion was most significant statistically(p<.05) in obstacle over walking with 20cm block.

• 기본간호학회지
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• 제17권3호
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• pp.314-323
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• 2010

Purpose: This study was performed to identify skin hydration status and skin surface pH according to the body parts of the aged with immobilization. Methods: The subjects were 101 aged patients in a hospital and a institution for the elderly in Seoul. Data for skin hydration and skin surface pH were collected using corneo-meter and skin pH-meter. The body parts of measurement were 10 parts; face, forearm, back of the hand, flank, upper abdomen, leg, back of the foot, heel, scapular, and sacrum. The data were analyzed by SPSS/WIN 12.0 program. Results: Skin hydration status were relatively low especially on lower extremity and back of body, and skin surface pH of scapular and sacrum were high. There was significant negative correlation between skin hydration status and skin surface pH on the 6 body parts. Conclusion: Skin hydration status and skin surface pH, especially on scapular, sacrum, and lower extremity need to be considered as important control factors for increasing skin health status of the aged with immobilization.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.30-37
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• 1999

This paper represents the development of the brake system for the inline skate using bellows. The inline skate that is used at present has defects due to frequent impulse, which weakens the breaking force by damaging the parts. Therefore to solve these problems a break system for the inline skates using hydraulics is suggested. To solve the oil leakage problems, bellows is used. Also to prevent the breaks from not touching the ground when skating the bellows is placed at the heel, high as possible. To obtain fast response speed, the ratio of inner diameter of the bellows is changed so that with only a small displacement from the bellows the rubber pad attached to the bellows will touch the ground fast. The performance of the break system using bellows depends on the optimal design of the bellows. Therefore the parameters that changes the form of the bellows are tested and also the interaction between the forces are investigated. The performance of new model brake system with bellows and old model system with only a rubber pad without bellows was estimated through observation of braking posture.

• Steel and Composite Structures
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• 제46권4호
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• pp.577-589
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• 2023

In this study, on-site testing was carried out to investigate the vibration performance of a cold-formed thin-walled steel floor system. Ambient vibration, walking excitation (single and double persons), and impulsive excitation (heel-drop and jumping) were considered to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes) and vertical acceleration response. Meanwhile, to discuss the influence of cement fiberboard on structural vibration, the primary vibration parameters were compared between the systems with and without the installation of cement fiberboard. Based on the experimental analysis, the cold-formed thin-walled steel floor possesses high frequency (> 10 Hz) and damping (> 2%); the installed cement fiberboard mainly increases the mass of floor system without effectively increasing the floor stiffness and may reduce the effects of primary vibration parameters on acceleration response; and the human-structure interaction should be considered when analyzing the vibration serviceability. The comparison of the experimental results with those in the AISC Design Guide indicates that the cold-formed thin-walled steel floor exhibits acceptable vibration serviceability. A crest factor 𝛽_rp (ratio of peak to root-mean-square accelerations) is proposed to determine the root-mean-square acceleration for convenience.

• 한국의상디자인학회지
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• 제11권2호
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• pp.183-195
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• 2009

In this study, foot shapes were compared between the men in their 20's and 60's, with the application of 3-dimensional measurement data, and the classification was established in consideration of each of their features. The results are as follows: 1. The investigation into the differences between the groups for the 3-dimensional measurement items of the men in their 20's and 60's indicated that those in their 20's had larger values than those in the 60's age group for all of the length items, while those in the 60's age group had larger values for all of the angle items. 2. The analysis of the constituting factors for the feet of those in their 60's and 20's resulted in the 7 items for the 20's age group and 8 items for those in the 60's age group. 3. The comparison of foot classifications for the 60's age group and 20's age group presented 3 types each for both groups, but the features of each type was different. To examine each characteristic by each type and age group, following can be determined of the 60's age group. Type 1 had a thick instep, high malleolus position and heel and a thick formed ankle. Type 2 the entire foot was small, and the big toe was formed in such a way that it tened to bend toward the inside. When the whole size compared with similar Type 1, Type 3 had a low instep, a low heel, the big toe did not bend and ankle form was thin. The following can be determined of the 20's age group. Type 1 had narrow width a thin ankle and the big toe was formed in such a way that it bended toward the inside. Compared with length, Type 2 had wide width and a thick ankle. Type 3 had a larger overall size, thick instep and wide and the toe was big, but the characteristic of inside and outside of a malleolus position was low and the big toe's form showed no tendencies to bend.

• 콘크리트학회논문집
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• 제16권2호
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• pp.221-228
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• 2004

본 연구에서는 현장 측정과 유한요소 해석을 이용하여 기존 아파트 바닥의 수직진동 성능 평가를 수행하였다. 평가에 사용된 기준은 ATC-1(1999) 기준과 AISC-11(1997) 기준, 그리고 일본건축학회 기준(1991)이며, 우리나라 사람의 감성을 고려하기 위해 선행연구에서 수행된 인지실험으로 제안된 인지곡선(2003)을 함께 사용하였다. 뒤꿈치 충격하중(heel drop)과 보행하중(walking)을 이용한 현장 측정으로 바닥판의 동특성을 파악하고 최대가속도값을 측정하여 이를 기준과 비교하였다. 대상 바닥판의 동특성은 고유진동수가 17Hz~22Hz이고, 감쇠비는 3~4%이다. 수직진동 성능 평가에 앞서 현행 기준의 최소두께 기준과 대상 바닥판의 두께를 비교 검토한 결과 기준의 최소값은 만족하나, 단부 슬래브에 대한 10% 증대 항목을 적용하면 만족하지 않았다. 대상 바닥의 보행하중에 대한 최대가속도값은 모두 ATC-1(1999) 및 AISC-11(1997) 기준과 일본건축학회 기준(1991)을 만족하지 못하였고, 뒤꿈치 충격하중에 대한 최대가속도값은 64RC-L만 일본건축학회 기준(1991)의 제한값에 근접하며 만족하였다. 우리나라 사람의 감성이 고려된 인지곡선(2003)과의 비교 결과 보행하중과 뒤꿈치 충격하중에 대한 대상 바닥판의 최대가속도값은 모두 '약하게 인지' 수준과 '인지하지 못함' 수준에 사이에 분포하고 있어, '인지하지 못함'을 인지의 하한선으로 본다면 대상 바닥판에서는 모두 진동을 인지하게 된다. 또한 유한요소 해석으로 구한 1KN의 정적 집중하중에 대한 처짐은 모두 1mm 미만으로 10Hz 이상의 고유진동수를 갖는 바닥판에 대하여 고려하도록 하는 ATC-1(1999) 및 AISC-11(1997)의 최소 강성 기준은 만족함을 알 수 있었다.

• 한국운동역학회지
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• 제15권4호
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• pp.153-168
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• 2005

The purposes of this study were to determine the influence of midsole hardness and sole thickness of sports shoes on ball flex angle and position with increment of running velocity. The subjects employed for this study were 10 college students who did not have lower extremity injuries for the last one year and whose running pattern was rearfoot striker of normal foot. The shoes used in this study had 3 different midsole hardness of shore A 40, shore A 50, shore A 60 and 3 different sole thickness of 17cm, 19cm, 21cm. The subjects were asked to run at 3 different speed of 2.0m/sec, 3.5m/sec, 5.0m/sec and their motions were videotaped with 4 S-VHS video cameras and 2 high speed video cameras and simultaneously measured with a force platform. The following results were obtained after analysing and comparing the variables. Minimum angle of each ball flex position were increased with the increment of running velocity and shoe sole thickness(P<0.05), but mid-sole hardness did not affect minimum ball flex angle. The position which minimum angle was shown as smallest was 'D'. Midsole hardness and sole thickness did not affect time to each ball flex minimum angle, total angular displacement of ball flex angle, and total angular displacement of torsion angle(P<0.05). The position which minimum angle was appeared to be earliest was similar at walking velocity, and E and F of midfoot region at running velocity. Total angular displacement of ball flex position tended to increase as shifted to heel. It was found that running velocity had effects on ball flex angle variables, but shoe sole thickness partially affected. It would be considered that running velocity made differences between analysis variables at walking and running when designing shoes. Also, it was regarded that shoes would be developed at separated region, because ball flex angle and position was shown to be different at toe and heel region. It is necessary that midsole hardness and thickness required to functional shoes be analyzed in the further study.

• 한국의류학회지
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• 제29권1호
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• pp.79-90
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• 2005

The purpose of this study is to find out the wearing conditions and cause of discomfort with shoes for male college students which will provide useful information fur the shoes manufacturer. The questionnaire survey was conducted on 346 male college students on purchasing practices, wearing conditions, and overall satisfaction with shoes. The results were as follows: Male college students have a tendency to have longer buying cycles and buy more expensive shoes compare to high school students. The order of criteria considered fer purchasing was shape, price, style coordination with clothing. The order of criteria considered for purchasing differed according to their major, economic status and purchasing place. Most of them have two pairs of white or black sports shoes and one pair of either black or brown dress shoes. The most popular material was man made leather but college students have more leather shoes than high school students. There were differences between high school students and college students in wearing conditions, how many they have, material and color. The varieties of shoes differed by season. They were satisfied with their shoes' design and color but unsatisfied with qualify or the material and durability of the shoes. Due to the pressure of the shoes, they experienced discomfort such as numbness, blisters on the feet and red skin. They experienced discomfort on the soles of the feet. The causes of discomfort were shape, width, hight of the heel, material and length in order. Dress shoes cause more discomfort than sport shoes due to the hardness of material, and flexibility of the sole. Since the material differed by the price, the degree of discomfort significantly differed by price too.