• Title/Summary/Keyword: Pressure support

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A Comparison of Standard Methods for Evaluating the Water Resistance of Shell Fabrics

  • Kwon, Myoung-Sook;Nam, Youn-Ja
    • The International Journal of Costume Culture
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    • v.4 no.3
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    • pp.241-248
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    • 2001
  • Re water resistance of shell fabrics intended for we in outdoor apparel was measured using three different standard test methods, ASTM D 751, hydrostatic resistance, procedure A(Mullen test -- with and without a fabric support) and Procedure B (Hydrostatic head test). A database of information on their water resistance performance was created. The data collected with different methods were correlated and the advantages and disadvantages of each method were compared. The Mullen test with a support appears to give higher and more favorable water resistance values on shell fabrics preventing fabric rupture during the test. The hydrostatic head test gave lower hydrostatic pressure values than those measured on the two Mullen tests. The Mullen test is recommended for testing the water resistance of fabrics that high a relatively high water resistance because the Mullen tester applies a wide range of pressure. The hydrostatic head test is recommended for testing the fabrics that have relatively low water resistance. The area of the fabric sample that is in contact with the water is smaller in the Mullen test, so higher pressure levels can be reached and more samples should probably be tested to get a representative value for each fabric types. Furthermore, the hydrostatic head test was deemed more repeatable than the Mullen tests in his study.

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Performance Evaluation of a Micro Thruster Utilizing Hydrogen Peroxide Decomposition (과산화수소 분해반응을 이용한 초소형 추력기 성능평가)

  • Lee, Jeong-Sub;An, Sung-Yong;Kwon, Se-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.102-105
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    • 2007
  • The performance evaluation of the micro thruster utilizing hydrogen peroxide decomposition is described. The catalyst bed was made of porous ceramic material($Isolite^{(R)}$) with large surface to mass ratio. 14%wt platinum was loaded on the catalyst support as a catalyst. Hydrogen peroxide with 85% concentration was used as a monopropellant. The length of the catalyst bed and the feed pressure of the hydrogen peroxide were taken as the parameters for the experiment. All experiments were carried out under cold start condition for 30 seconds. The $c^*$ efficiency was evaluated for each test case using measured pressure data. For the catalyst support length of 30 mm and feed pressure at 5.51 bar, satisfactory $c^*$ efficiency beyond 95% was observed.

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Treatment for the Deformed Support of Oil Paintings Using Low-Pressure Table and New Materials (저압 테이블과 신소재를 이용한 유화의 지지대 변형에 대한 처리작업)

  • Kim, Joo-Sam
    • Journal of Conservation Science
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    • v.6 no.1 s.7
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    • pp.71-78
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    • 1997
  • Oil painting shows a wide variety of damages due to differentcohesiveness between materials and different responses to temperature and humidity. The deforming flatness of canvas is a major cause of deterioration. The heat, pressure and moisture, and classical materials which had been traditionally used to correct the deformation of supports have caused damages to the paintings. In modern restoration of paintings, new methods have been developed to avoid the use of such potentially harmful elements. In this paper the correcting of deformed support with the use of low-pressure table, deformation correction frame and new materials, which has been developed both to protect the works and to maximize the effect of restoration.

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Development of Brace-type Wearable Robot for Lumbar Stabilization (요부 안정화를 위한 복대형 입는 로봇 개발)

  • Joowan Kim;Jaehoon Sim;Keewon Kim;Sungun Chung;Jaeheung Park
    • The Journal of Korea Robotics Society
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    • v.18 no.2
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    • pp.189-196
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    • 2023
  • An abdominal brace is a recommended treatment for patients with lumbar spinal disorders. However, due to the nature of the static brace, it uniformly compresses the lumbar region, which can weaken the lumbar muscles or create a psychological dependence that worsens the condition of the spine when worn for an extended period of time. Due to these issues, doctors limit the wearing time when prescribing it to patients. In this paper, we propose a device that can dynamically provide abdominal pressure and support according to the lumbar motion. The proposed device is a wearable robot in the form of a brace, with actuators and a driving unit mounted on the brace. To enhance wearability and reduce the weight of the device, worm gears actuator and a multi-pulley mechanism were adopted. Based on the spinal motion of the wearer measured by the Inertia measurement unit sensors, the drives wire by driving pulley, which provide tension to the multi-pulley mechanism on both sides, dynamically tightening or loosening the device. Finally, the device can dynamically provide abdominal pressure and support. We describe the hardware and system configuration of the device and demonstrate its potential through basic control experiments.

Evaluation of Muscle Fatigue and Subjective Fatigue depending on the Hip Seat and Waist Support Band of Baby Carrier (아기 띠의 힙시트와 허리지지 유무에 따른 근피로도와 주관적 피로도 평가)

  • Lee, Heeran;Hong, Kyung Hwa
    • The Korean Fashion and Textile Research Journal
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    • v.19 no.4
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    • pp.504-514
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    • 2017
  • Discomfort as well as muscular pain and musculoskeletal diseases occur in cases of stressed posture due to prolonged pressure. Therefore, the American Academy of Orthopaedic Surgeons (AAOS) and Pediatric Orthopaedic Society of North America (POSNA) recommend that bags that weigh no more than 15 - 20% of the wearer's weight. However, despite the prolonged pressure from using baby carriers, there are no recommendations and limited studies on how to protect wearers. Therefore, this study investigates subjective fatigue according to the usage of waist support and hip seat. Based on this, muscle fatigue and secondary subjective fatigue according to three types of currently commercial baby carriers (X-type, H-type, and H-hip type) were measured. Subjective comfortability was evaluated on a 5 point Likert-scale and subjective fatigue was evaluated on Borg's CR-10 scale. Objective muscle fatigue was also compared by measuring and analyzing electromyogram (EMG). The results of primary subjective fatigue showed statistically significant changes in the shoulders, waist, calves, and soles of the feet according to the usage of hip seats and waist support. Electromyogram measurements also showed less muscle fatigue at the upper trapezius muscle and thoracic erector spine muscle for the H-hip seat baby carrier, which has both waist support and hip seat, compared to an X-type baby carrier, which has neither. However, results of subjective fatigue showed opposite results at the waist despite having same results at the shoulders and beneath the shoulders. This show discrepancies between objective muscle fatigue and subjective fatigue; therefore, that both aspects must be taken into consideration when developing ergonomic baby carriers.

The study about variables influencing emotional, normative, and functional marriage intentions of unmarried men and women (미혼남녀의 정서적·당위적·기능적 결혼의향에 영향을 미치는 변인 연구)

  • Park, Hye-Min;Jeon, Gwee-Yeon
    • Journal of Family Relations
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    • v.22 no.4
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    • pp.53-80
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    • 2018
  • Objectives: The purpose of this study was to investigate individual awareness variables influencing emotional, normative, and functional marriage intentions of unmarried men and women. Independent variables were values of offspring, perceptions to unmarried life, attitudes toward multiple role planning, perceptions and availabilities of marriage-related policies, views on the marriageable age, psychological burdens of pressure to marriage by significant people, and views on parents' support for marriage fund. Method: 553 unmarried men and women in Daegu, Korea were surveyed, and the data were analyzed using descriptive statistics, factor analysis, multivariate analysis of variance(MANOVA), multiple regression analysis, and hierarchical regression analysis with SPSS 22.0. Results: First, this study was more exploratory and in-depth approach to marriage intentions than precedent studies. The sub factors of marriage intentions were emotional, normative, and functional marriage ones. Second, emotional marriage intention showed significant differences depending on gender, dating, views on the marriageable age, and degree of acceptance of parents' support for marriage fund. Among the individual awareness variables, values of offspring, perceptions to unmarried life, attitudes toward multiple role planning, and psychological burdens of pressure to marriage personally or by friends influenced emotional marriage intention. Third, normative marriage intention showed significant differences depending on gender, religion, occupational status, employment condition, dating, views on the marriageable age, and degree of acceptance of parents' support for marriage fund. Among the individual awareness variables, values of offspring, perception to unmarried life, attitudes toward multiple role planning, view on the marriageable age, availabilities of marriage-related information offering policies, and psychological burdens of pressure to marriage by mother influenced normative marriage intention. Fourth, functional marriage intention showed significant differences depending on gender, job, parents' support for marriage fund, views on the marriageable age, and degree of acceptance of parents' support for marriage fund. Among the individual awareness variables, functional marriage intention was influenced by values of offspring, perception about unmarried life, attitudes toward multiple role planning, and degree of acceptance of parents' support for marriage fund. Finally, the hierarchical regression analysis showed that individual awareness variables influenced on marriage intentions. Especially, values of offspring, perceptions to unmarried, and attitudes toward multiple role planning influenced on emotional, normative, and functional marriage intentions in common. Conclusions: The findings from these analyses suggest that the selective process based on the individual awareness has become very significant to having marriage intentions. Therefore, this study will contribute as the basic data on national marriage-related policies. Furthermore, this study will be able to use to think about the marriage intention as a task to be preceded by the national policy in order to prepare for Korea 's low fertility and aging phenomenon.

A study on EPB shield TBM face pressure prediction using machine learning algorithms (머신러닝 기법을 활용한 토압식 쉴드TBM 막장압 예측에 관한 연구)

  • Kwon, Kibeom;Choi, Hangseok;Oh, Ju-Young;Kim, Dongku
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.24 no.2
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    • pp.217-230
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    • 2022
  • The adequate control of TBM face pressure is of vital importance to maintain face stability by preventing face collapse and surface settlement. An EPB shield TBM excavates the ground by applying face pressure with the excavated soil in the pressure chamber. One of the challenges during the EPB shield TBM operation is the control of face pressure due to difficulty in managing the excavated soil. In this study, the face pressure of an EPB shield TBM was predicted using the geological and operational data acquired from a domestic TBM tunnel site. Four machine learning algorithms: KNN (K-Nearest Neighbors), SVM (Support Vector Machine), RF (Random Forest), and XGB (eXtreme Gradient Boosting) were applied to predict the face pressure. The model comparison results showed that the RF model yielded the lowest RMSE (Root Mean Square Error) value of 7.35 kPa. Therefore, the RF model was selected as the optimal machine learning algorithm. In addition, the feature importance of the RF model was analyzed to evaluate appropriately the influence of each feature on the face pressure. The water pressure indicated the highest influence, and the importance of the geological conditions was higher in general than that of the operation features in the considered site.

Development of an Algorithm for the Prevention and Management of Pressure Ulcers (입원 환자의 욕창예방과 중재를 위한 알고리즘 개발)

  • Kim, Jin-Mi;Park, Jeong-Sook
    • Korean Journal of Adult Nursing
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    • v.22 no.4
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    • pp.353-364
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    • 2010
  • Purpose: The purpose of this study was to develop an algorithm for preventing and managing of pressure ulcer and to verify the its appropriateness. Methods: The first step was development of a pre-algorithm through a literature review and expert opinion. The second step was to establish content validity by submitting the algorithm questionnaires about the content to 12 experts. The third step was the revision of the algorithm. The fourth and last step was to establish the clinical validity of the algorithm with 25 experienced nurses. Results: For the ease of the practitioner the algorithm for prevention and the management of pressure ulcers was confined to one page depicting the main algorithm pathway and seven stepwise guidelines. The guidelines included skin care of pressure ulcer prevention, mechanical loading care, support surface care, reposition care of pressure ulcer, and Stages II, III and IV explanations along with debridement/wound irrigation and infection control. Most of all algorithm courses chosen more than 80% of agreement by expert index of content validity. The usefulness, appropriateness, and convenience of the algorithm were demonstrated through clinical validity with intensive care unit and ward nurses. Conclusion: The algorithm will improve the quality of pressure ulcer nursing care as it provides a model for decision making for clinical nurses as well as providing consistent and integrated nursing care for patients with pressure ulcer throughout an institution.

The steam turbine condenser pressure optimization with different heat rate correction curves (각기 다른 열소비율 보정곡선을 갖는 증기터빈의 최적 복수기 운전압력 설정)

  • Cho, Cheon-Hwan;Baek, Nam-Ho;Hur, Jin-Hyek;Lee, Jae-Heon;Moon, Seung-Jae;Yoo, Ho-Sun
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.224-227
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    • 2008
  • The present study performs a test of a change in a condenser pressure on two kinds of power plants having different condenser pressure-heat rate correction curve and evaluates the results. According to a result of the test, it is confirmed that a sub-critical drum type steam power plant is optimally operated at the condenser pressure of 38㎜Hga that is designed, even during winters. On the other hand, it can be found that a supercritical once through type steam power plant operated at the condenser pressure that is reduced below a design value, that is, up to 28㎜Hga during winters is advantageous in view of turbine efficiency and is operated without a problem in facility operation such as moisture erosion, turbine vibration, etc. Also, the present study compares and reviews a condenser pressure-heat rate correction curve proposed by a manufacturer and a test value. The present study proposes optimum condenser operation pressure capable of concurrently satisfying the stable operation and efficiency improvement of the power plant facility that is operating, making it possible to support an efficient operation of a power plant.

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A Technique for Defect Detection of Condenser Tube in Support Plate Region using Guided Wave (유도초음파를 이용한 복수기 튜브지지판 영역에서의 결함검출기법)

  • Kim, Yong-Kwon;Park, Ik-Keun;Park, Sae-Jun;Ahn, Yeon-Shik;Gil, Doo-Song
    • Journal of Welding and Joining
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    • v.30 no.6
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    • pp.36-41
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    • 2012
  • General condensers consist of many tubes supported by tube sheets and support plates to prevent the deflection of the condenser tubes. When a fluid at high pressure and temperature runs over the tubes for the purpose of transferring heat from one medium to another, the tubes vibrate and their surface comes into contact with the support plates. This vibration causes damage to the tubes, such as cracks and wear. We propose an ultrasonic guided wave technique to detect the above problems in the support plate region. In the proposed method, the ultrasonic guided wave mode, L(0,1), is excited using an internal transducer probe from a single position at the end of the tube. In this paper, we present a preliminary experimental verification using a super stainless tube and show that the defects can be discriminated from the support signals in the support region.