• Title/Summary/Keyword: Stretch rate

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A Study on the Development of Sleep Monitoring Smart Wear based on Fiber Sensor for the Management of Sleep Apnea (수면 무호흡증 관리를 위한 섬유센서 기반의 슬립 모니터링 스마트 웨어 개발에 관한 연구)

  • Park, Jin-Hee;Kim, Joo-Yong
    • Science of Emotion and Sensibility
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    • v.22 no.1
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    • pp.89-100
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    • 2019
  • Sleep apnea, a medical condition associated with a variety of complications, is generally monitored by standard sleep polysomnography, which is expensive and uncomfortable. To overcome these limitations, this study proposes an unconstrained wearable monitoring system with stretch-fiber sensors that integrate with the wearer's clothing. The system allows patients to undergo examinations in a familiar environment while minimizing the occurrence of skin allergies caused by adhesive tools. As smart clothing for adult males with sleep apnea, long-sleeved T-shirts embedding fibrous sensors were developed, enabling real-time monitoring of the patients' breathing rate, oxygen saturation, and airflow as sleep apnea diagnostic indicators. The gauge factor was measured as 20.3 in sample 4. The maximum breathing intake, measured during three large breaths, was 2048 ml. the oxygen saturation was measured before and during breath-holding. The oxygen saturation change was 69.45%, showing a minimum measurable oxygen saturation of 70%. After washing the garment, the gauge factor reduced only to 18.0, confirming the durability of the proposed system. The wearable sleep apnea monitoring smart clothes are readily available in the home and can measure three indicators of sleep apnea: respiration rate, breathing flow and oxygen saturation.

Development of Tight-Fitting Garments with a Portable ECG Monitor to Measure Vital Signs (휴대용 심전도 기기와 직물형 전극을 이용한 생체정보 측정용 밀착 의복 개발)

  • Jeong, Yeon-Hee; Kim, Seung-Hwan;Yang, Young-Mo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.34 no.1
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    • pp.112-125
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    • 2010
  • A Holter monitor is used for ECG monitoring of ambulatory daily life in hospital. However, the use of this apparatus causes skin allergies and discomfort in patients because of the attachment gel and tapes used to attach disposable electrodes to the skin. In this study, the development of tight-fitting clothing connected to a portable Holter monitor was proposed. In addition, the use of conductive fabrics as electrodes was proposed; this will enable the use of garments in u-health care for measuring ECG signals. The male subjects were university students in the ages of 20 to 24. Subjective wear sensations of the experimental garments were rated using seven Likert scales. A Likert type scale was used for the evaluation and a 7 point score indicates that it provided the best fit as a tight-fitting upper clothing. Clothing pressure was measured using an air-pack-type pressure sensor (model AMI 3037-2) at 4 locations (the conductive fabric electrode) As results, a male basic sloper for upper clothing was developed and that pattern was manipulated to the tight fit pattern by considering the reduction rate of the percentage stretch in the fabric. The developed tight-fitting garment was superior in terms of subjective sensation and 6t. The mean pressure of the garment with reduction rates of 40% in width and of 50% in length was 8.45gf/$cm^2$. A conductive fabric electrode was developed by considering the sewing method and the developed electrode was detected well. The ECG data were recorded for 13 hr 19 min 44 sec and the artifacts in the ECG signals were recorded for 9 hr 3 min 46 sec (total time: 22 hr 23 min 23 sec). The artifacts data were obtained during heavy activities.

A Study on the Flame Curvature Characteristics in a Lifted Flame (부상화염에서 화염 곡률반경 특성에 관한 연구)

  • Ha, Ji-Soo;Kim, Tae-Kwon;Park, Jeong;Kim, Kyung-Ho
    • Journal of the Korean Institute of Gas
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    • v.14 no.2
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    • pp.34-39
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    • 2010
  • Flame propagation velocity is the one of the main mechanism of the stabilization of triple flame. To quantify the triple flame propagation velocity, Bilger presents the triple flame propagation velocity through the experiment, depending on the mixture fraction gradient, based on the laminar jet flow theory. However, in spite of these many analyses, there has not been any attempt to quantify the triple flame propagation velocity with the radius of flame curvature. In the present research, a relation of the flame propagation velocity is proposed with the radius of flame curvature for the flame stabilization mechanism. As a result, we have shown that the height of lifted flame is determined with the nozzle diameter and exit velocity of fuel and presented that the radius of flame curvature is proportion to the nozzle exit velocity of fuel and height of lifted flame. Therefore, the importance of the radius of flame curvature has to be recognized. To discribe the flame stabilization mechanism, Bilger's formula has to be modified with flame curvature effect.

Selection and Design of Functional Area of Compression Garment for Improvement in Knee Protection (무릎 안전성 향상을 위한 컴프레션 의복의 기능적 디자인 영역 선정과 설계법)

  • Lee, Hyo Jeong;Kim, Nam Yim;Hong, Kyung Hi;Lee, Ye Jin
    • Korean Journal of Human Ecology
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    • v.24 no.1
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    • pp.97-109
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    • 2015
  • Recently, because the market for compression wear now includes all consumers, not just professionals, various items for recovery after exercising or for enhanced effects from exercise have been introduced. In this research, a systematic and stepwise design process was proposed to develop compression garment that has both functional area and appropriate pressure to protect the knee when exercising. The U-V format functional area that wraps underneath the knee was selected by considering the shape and change in the skin length when bending the knee. After the selection of the functional area, a total of seven knee design areas, including the existing product, were designed to determine the appropriate pressure. After various movements, the compression garment was ranked in terms of support of the knee, level of pressure, discomfort of seam line, and comfort of popliteal; the preferred design was selected using the quad method. Four compression wear garments were produced using two selected preferred designs; the wear evaluation was performed using a seven-point Likert scale. As a result, the optimal reduction rate of the pattern was calculated based on Ziegert and Keil's method. The applied percentage of the fabric stretch at the upper part of the crotch was 66% for the width and 50% for the length; for the lower part of the crotch, only 66% for the width was applied. Moreover, it was determined that the design of the U-V knee protection part was preferred when a 7 mm square was placed at a 1 mm distance because this not only supports the knee but also allows the fabric to accommodate various skin deformations.

A Study of Automobile Product Design using Hole Expansion Testing of High Strength Steels (고장력강의 구멍 확장 실험을 이용한 자동차부품 설계연구)

  • Park, B.C.;Bae, K.U.;Gu, S.M.;Jang, S.H.;Hong, S.H.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.19 no.6
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    • pp.337-343
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    • 2010
  • Current need of weight reduction in automotive part increases the application for high strength steel (HSS). The various types of high strength steels have been used to produce chassis part, control arms and trailing arms for weight reduction and increasing of fatigue durability such as dual phase steel (DP) and ferrite bainite steel (FB). But, DP and FB steels have proven to show inferiority in durability as well as press formability. Edge cracking occurred often in flange forming and hole expansion processes is the major failure encountered. This paper discussed the behavior of edge stretchability of high strength steel of DP and FB steels. Experimental works have been conducted to study the effect of punch clearance and burr direction on hole expansion ratio (HER). Also finite element simulation (FEM) has been preformed to clarify the mechanism of flange crack and support the experimental results on HER of DP and FB steels. It was simulated the whole process of blanking process following by hole expansion process and ductile fracture criterion named the modified Cockcroft-Latham model which was used to capture the fracture initiation. From the hole expansion tests and FEM simulation studies it was concluded that ferrite bainite steel showed better stretch-flangeability than dual phase steel. It was attributed to the lower work hardening rate of ferrite bainite steel than dual phase steel at the sheared edge.

The Enforcement Scheme of the Overspeeding vehicle by Travel Speed (구간과속단속시스템의 도입 방안 연구)

  • Han, Won-Seop;Kim, Man-Bae;Hyeon, Cheol-Seung;Yu, Seong-Jun
    • Journal of Korean Society of Transportation
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    • v.23 no.1
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    • pp.21-32
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    • 2005
  • At present automated speed enforcement system in Korea control overspeed vehicle only in the specific spot. Because the drivers generally recognize the previous stated fact, they reduce a speed only in the establishment location of systems and increase rapidly again as soon as it passes the location. we have known that the rate of traffic risk at the tunnel, bridge and curve road segment is higher than other road section. Therefore, it needs speed control in them. In such a case, it is necessary to establish the automated traffic enforcement system based on the travel time speed of an individual vehicle over a pre defined stretch of road. In this study, the application limit of existing spot overspeed enforcement system was studied through an analysis of traffic flow characteristics in the tunnel, bridge and curve section. Also we found out the optimal distance of segment and the most suitable location to an application of the overspeed vehicle by travel time speed through an analysis of the road structure, traffic condition and accident numbers in the road.

Analysis of Body Composition and Functional Physical Performance in Urban-Dwelling Elderly Women with or without Obesity (도시 거주 여성 노인의 비만 유무에 따른 신체구성, 상⋅하지 근력 및 신체활동 능력 분석)

  • Choi, Seung-Jun
    • PNF and Movement
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    • v.19 no.3
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    • pp.331-340
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    • 2021
  • Purpose: The purpose of this study was to investigate the differences in body composition, upper and lower limb muscle strength, and functional physical ability in urban-dwelling elderly women with or without obesity. Methods: All study participants were assigned to the normal weight group (n=8, BMI<25) and the obesity group (n=7, BMI>25) based on their obesity rate. Anthropometric measurement was conducted and body composition was measured. For the upper and lower limb strength, grip strength and maximal isometric knee extension and flexion were evaluated by a dynamometer. The senior fitness test was performed to measure functional ability. Data analysis was conducted by the independent t-test and the alpha level was set at 0.05. Results: The waist, hips, and thighs of obese elderly women were thicker than those of normal-weight elderly women. This physical difference resulted from body fat mass, not muscle mass. Despite a similar level of limb muscle mass between the two groups, the upper limb grip strength was higher (24.00% for left, 19.95% for right) in the normal-weight women than the obese women (p<0.05), but otherwise there was no difference in maximal knee flexion or extension isometric strength. Functional physical ability showed no difference in a 30-second chair sit and stand test and a six-minute walk test, but a 30-second arm-curl (11.00% for left, 14.81% for right), back stretch (8.54cm for left, 8.99cm for right), chair sit and reach (9.22cm for left, 6.24cm for right), and 2.44 meter round trip walk (0.62 sec, 9.39%) were faster in performance for normal-weight elderly women than obese elderly women (p<0.05). Conclusion: Taken together, despite similar levels of upper and lower extremity muscle mass, normal-weight elderly women showed higher performance in upper limb strength, flexibility, and agility than obese elderly women, but there was no difference in lower extremity functional muscle strength and cardiopulmonary endurance.

Numerical Study on H2 Preferential Diffusion Effect in Downstream Interactions between Premixed H2-air and CO-air Flames (상호작용 하는 H2-공기/CO-공기 예혼합화염에 미치는 H2 선호 확산 영향에 대한 수치적 연구)

  • Chung, Yong Ho;Park, Jeong;Kwon, Oh Boong;Keel, Sang In;Yun, Jin Han
    • Journal of the Korean Society of Combustion
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    • v.18 no.4
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    • pp.37-43
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    • 2013
  • The effects of preferential diffusion of hydrogen in interacting counterflow $H_2$-air and CO-air premixed flames were investigated numerically. The global strain rate was varied in the range $30-5917s^{-1}$, where the upper bound of this range corresponds to the flame-stretch limit. Preferential diffusion of hydrogen was studied by comparing flame structures for a mixed average diffusivity with those where the diffusivities of H, $H_2$ and $N_2$ were assumed to be equal. Flame stability diagrams are presented, which show the mapping of the limits of the concentrations of $H_2$ and CO as a function of the strain rate. The main oxidation route for CO is $CO+O_2{\rightarrow}CO_2+O$, which is characterized by relatively slow chemical kinetics; however, a much faster route, namely $CO+OH{\rightarrow}CO_2+H$, can be significant, provided that hydrogen from the $H_2$-air flame is penetrated and then participates in the CO-oxidation. This modifies the flame characteristics in the downstream interaction between the $H_2$-air and CO-air flames, and can cause the interaction characteristics at the rich and lean extinction boundaries not to depend on the Lewis number of the deficient reactant, but rather to depend on chemical interaction between the two flames. Such anomalous behaviors include a partial opening of the upper lean extinction boundary in the interaction between a lean $H_2$-air flame and a lean CO-air flame, as well as the formation of two islands of flame sustainability in a partially premixed configuration with a rich $H_2$-air flame and a lean CO-air flame. At large strain rates, there are two islands where the flame can survive, depending on the nature of the interaction between the two flames. Furthermore, the preferential diffusion of hydrogen extends both the lean and the rich extinction boundaries.

The Effect of Washing Conditions on the Dimension and Mechanical Properties of Spandex Yarns (세척조건에 스판덱스사의 길이와 기계적 성질에 미치는 영향)

  • Chung, Hae-Won;Kim, Mi-Kyung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.29 no.12 s.148
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    • pp.1619-1626
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    • 2005
  • The durability of a stretch fabric is mainly related to the change in the dimension and mechanical properties of elastomeric fibers during wearing and washing. In this study, we examined the effects of washing temperature, presoaking time and the number of washing cycles on the change in length, tenacity, elongation at break, and permanent elongation after six repeated cycles of $100\%$ extension and relaxation of spandex yams with varying fineness and with a different rate of extension during heat-set. The spandex yarns continued to shrink as the wash temperature and the number of wash cycles increased. In addition, the finer spandex yams decreased in length more than the thicker yams. The increase in temperature and presoaking time tended to cause a slight decrease in the tenacity and elongation at break of the spandex yarns. Permanent elongation of the spandex yams also increased as the temperature, presoaking time and the number of washing cycles increased. Moreover, an extended presoaking time followed by washing at $40\%$ like repeated washing cycles showed the great increase in the permanent elongation of spandex yams. The thinner spandex yin had a better elasticity than the thicker one, since the former had a lower permanent elongation percentage than the latter. Based on the DSC thermograms, the melting points of the spandex yarns after washing were almost the same as those of the spandex yarns before washing.

결장루형성술 환자 간호를 위한 일 연구

  • 모경빈
    • Journal of Korean Academy of Nursing
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    • v.1 no.1
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    • pp.27-43
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    • 1970
  • This study is designed to find out proper nursing activities for the needs of the colostomy patients, i.e., mental and psychological as well as physical needs for rapid recovery, and to help them build up the follow-up care for proper social adjustment. The study is based on 268 cases out of 381 colostomy patient's records kept in Ewha Womans University Hospital, Yonsei Medical Center, and National Medical Center in between the period from Jan. 1953 to Jan. 1970. The items of study are mainly on etiology, sex, age, duration of hospitalization, mortality rate, seasonal frequency, time from the onset of illness to the admission of the hospital, signs and symptoms. 1. Frequency of onset by etiology: Neoplastic disease 112 cases (42%), Inflammatory disease 33 cases (12%), Congenital malformation 30 cases (11%), Intussusception 25 cases (9.3%), Trauma 24 cases (9%), Volvulus 17 cases (6.3%), and Crohn's disease 6 cases (2.2%). 2. By sex: male 167 cases (62.9%), and female 101 cases (37.1%). So the ratio of portion of male and female 2:1. 3. By age: under 1·year·old 27 cases (10.1%) highest, 41-50 yrs 54 cases (20.2%), 51-60 yrs 42 cases (15.5%), above 71 yrs 5 cases (1.9%). 4. Duration of hospitalization: the shortest is 2-days and the longest is 470 days. 1-20-days 52%, 40-60 days 14%. 5. Mortality rate: Under the 10-days-admission 19.5%, and the beyond 30-days-admission 3.9%. 6. Seasonal frequency: Higher in summer (32% ). 7. Signs and symptoms: abdominal pain (56%), abdominal distention (54%), vomiting (40%), bloody mucoid diarrhea (38%) , pain of anal region (18%), abdominal tenderness, anorexia, indigestion, constipation, disuria, tenesmus, high fever and chilling sensation, bile tingled vomiting. Nursing activities for the patient's physical needs are as follows: Skin care for colostomy region, Prevention of colostomy constriction and depression, Removal of an offensive odor, The use of colostomy bag-selection for, and demonstration of the use of inexpensive colostomy irrigation equipment, Personal hygiene, general skin care, care of hair, finger nails and toe-nails, Oral hygiene, sleep and rest, aquate, Daily activities, etc. Measures for regulation of bowl movement. Keeping the instruction of taking food, Preparing the meal and help for anorexia, Constipation and it's solution, Prevention of diarrhea, helping the removal of mucous, and stretch constricted steam as needed. Nursing activities for pt's socio-psychological needs are as follows; Help the patient to make decision for the operation, Remove pt's anxiety toward operation and anesthesia, To meet the pt's spiritual needs at his death bed, Help to establish family and friends cooperation, Help to reduce anxiety at the time of admission and it's solution, Help to meet religious need, Help to remove pt's anxiety for loosing his job and family maintenance, Follow-up studies for 7 cases have been done to implement the present thesis. The items of the personal interviews with the patients are as follows: Acceptability for artificial anus, The most anxious thing they had in mind at the time of discharge, The most anxious thing they hat·e in mind at present, Their friends and family's attitudes toward the patient after operation, Relations with other colostomy patients, Emotional damage from the operation, Physical problem of enema, irrigation, Control of diet, Skin care, Control of offensive odor, Patient's suggestions to nurses during hospital stay and after discharge. In conclusion, the follow-up care for colostomy patients shares equal weight or perhaps more than the post-operative care. The follow-up care should include the spiritual care for moral support of the patient, to drag him out of isolation and estrangement, and make him fully participate in social activities. It is suggested that the following measures would help to rehabilitate the colostomy patients (1) mutual acquaintance with other colostomy patients if possible form a sort of club for the colostomy patient to exchange their experiences in care (2) through the team work of doctor, nurse and rehabilitation specialists, to have a sort of concerted effort for betterment of the patient.

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