• Title/Summary/Keyword: Pressure support

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Sloshing Impact Response Analysis for Insulation System of LNG CCS Considering Elastic Support Effects of Hull Structures (선체구조의 탄성지지 효과를 고려한 LNG 운반선 방열구조의 슬로싱 충격응답 해석법에 관한 연구)

  • Nho, In Sik;Ki, Min-Seok;Kim, Sung-Chan;Lee, Jang Hyun;Kim, Yonghwan
    • Journal of Ocean Engineering and Technology
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    • v.31 no.5
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    • pp.357-363
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    • 2017
  • The sloshing pressure acting on a membrane-type LNG CCS is a typical irregular impact load, and the structural response of a tank system induced by sloshing also shows very complex behavior, including fluid structure interaction. Therefore, it is not easy to accurately estimate the sloshing impact pressures and resulting structural response. Moreover, a huge time consuming process to deal with the enormous pressure data obtained during a model tank test and the following structural analysis would be inevitable. To reduce the computation time for structural analysis, in this study, a rational structural modeling strategy was considered, and a simplified scheme to analyze the dynamic structural responses of an LNG CCS was introduced, which was based on the concept of the linear combination of the triangular response functions obtained by a transient response analysis of structures under unit triangular impact pressure. A structural analysis of a real Mark III membrane type insulation system under the sloshing impact pressure time histories obtained by model tests was performed using the various proposed structural models and simplified analysis scheme. The results were investigated in detail, including the elastic support effects of the hull structure.

Reliability analysis of anti-seismic stability of 3D pressurized tunnel faces by response surfaces method

  • Zhang, Biao;Ma, Zongyu;Wang, Xuan;Zhang, Jiasheng;Peng, Wenqing
    • Geomechanics and Engineering
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    • v.20 no.1
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    • pp.43-54
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    • 2020
  • The limit analysis and response surfaces method were combined to investigate the reliability of pressurized tunnel faces subjected to seismic force. The quasi-static method was utilized to introduce seismic force into the tunnel face. A 3D horn failure mechanism of pressurized tunnel faces subjected to seismic force was constructed. The collapse pressure of pressurized tunnel faces was solved by the kinematical approach. The limit state equation of pressurized tunnel faces was obtained according to the collapse pressure and support pressure. And then a reliability model of pressurized tunnel faces was established. The feasibility and superiority of the response surfaces method was verified by comparing with the Monte Carlo method. The influence of the mean of soil parameters and support pressure, variation coefficients, distribution type and correlation of c-φ on the reliability of pressurized tunnel faces was discussed. The reasonable safety factor and support pressure required by pressurized tunnel faces to satisfy 3 safety levels were presented. In addition, the effects of horizontal seismic force, vertical seismic force and correlation of kh-kv on the reliability of pressurized tunnel faces were also performed. The method of this work can give a new idea for anti-seismic design of pressurized tunnel faces.

Effect of Joint Cohesive Strength on the Earth Pressure against the Support System in a Jointed Rock Mass (절리형성 암반지층 굴착벽체 작용토압에 대한 절리 점착강도의 영향)

  • Son, Moorak;Solomon, Adedokun
    • Journal of the Korean Geotechnical Society
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    • v.30 no.7
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    • pp.41-53
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    • 2014
  • This study examined the magnitude and distribution of the earth pressure on the support system in a jointed rock mass by considering different joint shear strength, rock type, and joint inclination angle. The study particularly focused on the effect of joint cohesive strength for a certain condition. Based on a physical model test (Son and Park, 2014), extended parametric studies were conducted considering rock-structure interactions based on the discrete element method, which can consider the rock and joint characteristics of rock mass. The results showed the earth pressure was strongly affected by the joint cohesive strength as well as the rock type and joint inclination angle. The study indicated that the effect of joint cohesive strength was particularly significant when a rock mass was under the condition of joint sliding. This paper investigates the magnitude of joint cohesive strength to prevent a joint sliding for each different condition. The test results were also compared with Peck's earth pressure, which has been frequently used for soil ground. The comparison indicated that the earth pressure in a jointed rock mass can be significantly different from that in soil ground. This study is expected to provide a better understanding of the earth pressure on the support system in a jointed rock mass.

The Effect of Calf Stiffness on Gait, Foot Pressure and Balance in Adults

  • Lee, JeonHyeong;Chang, JongSung
    • The Journal of Korean Physical Therapy
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    • v.31 no.6
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    • pp.346-350
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    • 2019
  • Purpose: The purpose of this study was to investigate the effects of calf tightness on gait, plantar pressure, and balance in adults. Methods: A total of 60 participants were divided into a normal group of 30 subjects with normal dorsiflexion angle (20-25 degrees) and an experimental group of 30 subjects with limited dorsiflexion angle (0-15 degrees) due to calf tightness. Gait ability and foot pressure of the subjects was measured with a treadmill, and the balance ability was measured by PROKIN system. Results: A significant difference in COP length, loading response, and single limb support was observed between groups. The COP length and single limb support ratio in the normal group was greater than in the experimental group, but the experimental group showed a higher ratio for loading response in the gait ratio. Conclusion: Our results indicated that calf tightness was negative effects on balance and gait ability, so assessment of the muscle tightness should be considered during exercise and treatment.

A Study of Characteristics of Foot Pressure Distribution in Trans-tibial Amputee Subjects (하퇴 의지 사용자의 족저압 분포 특성에 관한 연구)

  • Kim, Jang-Hwan;Cynn, Heon-Seock
    • Physical Therapy Korea
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    • v.8 no.3
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    • pp.1-10
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    • 2001
  • The purpose of this study was to compare the static pressure, dynamic pressure, dynamic pressure-time integral, relative impulse, and contact time between the sound lower limb and amputated lower limb in trans-tibial amputee subjects using Parotec system. Seventeen trans-tibial amputee subjects wearing endoskeletal trans-tibial prosthesis voluntarily participated in this study. The results were as follows: 1) In static standing condition, there were significantly higher static pressure in sound lower limb insole sensor of 10, 14, 15, 18, 19, 23, and 24 and in amputated lower limb insole sensor of 9, 12, and 16 (p<.05). 2) In dynamic gait condition, there were significantly higher dynamic pressure in sound lower limb insole sensor of 2, 18, 22, 23, and 24 and in amputated lower limb insole sensor of 5, 9, 10, 11, 12, 14, 15, and 16 (p<.05). 3) In dynamic gait condition, there were significantly higher pressure-time integral in sound lower limb insole sensor of 2, 4, 18, 19, 20, 21, 23, and 24 and in amputated lower limb insole sensor of 5, 11, 12, and 15 (p<.05). 4) In dynamic gait condition, there were significantly higher relative impulse in sound lower limb insole sensor of 18, 19, 20, 22, 23, and 24 and in amputated lower limb insole sensor of 5, 9, 10, 11, 12, and 15 (p<.05). 5) In dynamic gait condition, there was significantly higher percentage of contact time in push off phase of sound lower limb and in support phase of amputated lower limb (p<.05). These results suggest that trans-tibial amputee subjects had characteristics of shortened push off phase due to unutilized forefoot and of lengthened support phase with higher pressure in the midfoot.

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Effects of one-to-one Labor Support on Labor Pain, Labor Stress Response, Childbirth Experience and Neonatal Status for Primipara (일대일 분만지지간호가 초산모의 분만동통, 분만스트레스 반응, 분만경험 및 신생아 상태에 미치는 효과)

  • Hur, Myung-Haeng
    • Women's Health Nursing
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    • v.7 no.2
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    • pp.188-202
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    • 2001
  • This study was designed to investigate the effect of one-to-one labor support on labor pain, labor stress response, childbirth experience and neonatal status for primipara by a quasi experiment (nonequivalent control group pretest-posttest design), from April 30, 1999 to February 20, 2000. The subjects of this experiment consisted of eighty two primipara with single gestation, full term, uncomplicated pregnancies. Forty one were in the experimental group and forty one in the control group. Their mean age was 25.95 years, their mean gestation period was 39.9 weeks. A caring package of one-to-one labor support had three components. Physical support consisted of massage, back pressure, touch. Emotional support was provided by a continuous nurse's presence, acceptance and encouragement. Informational support involved teaching breathing skills, relaxation skills and knowledge about the labor process. Data assessed labor pain, pulse rate and blood pressure to measure labor stress response. Also, in measuring the value of labor stress response, plasma epinephrine, plasma norepinephrine and serum cortisol were measured. In the 24 hours after birth, the data for the postpartum mother's childbirth experiences was collected. Umbilical cord arterial blood pH, one minute and five minute Apgar score were measured after birth. Data was analyzed by t-test, $x^2$-test, repeated measures ANOVA, ANCOVA with SAS Program. The results were as follows; 1. Labor pain was significantly low in the experimental group(P=.016). 2. No significant group effects were found, but significant time effects were found for plasma epinephrine, norepinephrine, serum cortisol, pulse rate and blood pressure. 3. The childbirth experience of the experimental group was significantly more positive than the control group (P = .005). 4. The umbilical cord arterial blood pH of the experimental group was significantly higher than the control group(P=.014). There was no significant difference between the two groups in neonatal one minute and five minute Apgar scores. In conclusion, these findings indicate that one-to-one labor support could be effective in decreasing labor pain, and increasing positive childbirth experiences, also increasing the neonatal umbilical cord arterial blood pH for primipara. So, one-to-one labor support could be applied as an effective nursing treatment for primipara.

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Commentary on Soft Ground TBM Tunnel Face Support Calculation Methods (연약지반 TBM 터널 막장지보 계산방법 해설)

  • Jee, Warren Wangryul;Yoo, Jung Hyun
    • Tunnel and Underground Space
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    • v.28 no.2
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    • pp.186-192
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    • 2018
  • The German Tunnelling Committee (DAUB) recently published new recommendations for face support calculations; Zdenek Zizka and Markus Thewes of Ruhr University Bochum actively discuss and explain these new recommendations where these recommendations are intended to assist in choosing between various calculation methods which are also dependent on ground conditions. The guidelines also discuss important scientific approaches with face stability calculations, mainly those due to earth pressure and groundwater pressure on the tunnel face. This paper aims to explain these recommendations through Zdenek Zizak and Markus Thewes's discussion on these Tunnel Face Support Calculation Methods.

A Comparative Analysis on the e-Business Adoption Factors and Performance in Large and Small Companies (e-비즈니스 채택요인과 성과에 관한 대기업과 중소기업의 차이분석)

  • Lee, Dong-Man;Ahn, Hyun-Sook;Kim, Hyo-Jung
    • The Journal of Information Systems
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    • v.17 no.4
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    • pp.157-180
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    • 2008
  • The majority of studies was undertaken on large companies that had adopted e-Business or on the specific case of dot.com companies. However, despite this interest in the effect of the size of an organization on its approach to e-Business, little direct comparison has been undertaken between small and large companies. This study examined the differences of e-Business adoption factors and e-Business performance between large and small companies. Reviewing the literature, we suggest a research model and develop nine hypotheses to be tested. Data are collected from 109 companies Implemented e-business. The results of hypothesis testing show as follows. First, e-Business performance of efficiency has a positive influence of perceived e-Business advantage, top management support, organizational learning ability and financial slack. Second, e-Business performance of sales performance has a positive influence of top management support. Third, e-Business performance of customer satisfaction has a positive influence of technology competence, perceived e-Business advantage, top management support, financial slack and institutional pressure. Finally, there are differences in the e-business factors(perceived e-Business advantage, top management support, institutional pressure) and e-Business performance(efficiency) between large and small companies.

Respiratory support with heated humidified high flow nasal cannula in preterm infants

  • Jeon, Ga Won
    • Clinical and Experimental Pediatrics
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    • v.59 no.10
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    • pp.389-394
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    • 2016
  • The incidence of bronchopulmonary dysplasia (BPD) has not decreased over the last decade. The most important way to decrease BPD is by weaning the patient from the ventilator as soon as possible in order to reduce ventilator-induced lung injury that underlies BPD, and by using a noninvasive ventilator (NIV). Use of a heated, humidified, high flow nasal cannula (HHHFNC), which is the most recently introduced NIV mode for respiratory support in preterm infants, is rapidly increasing in many neonatal intensive care units due to the technical ease of use without sealing, and the attending physician's preference compared to other NIV modes. A number of studies have shown that nasal breakdown and neonatal complications were lower when using a HHHFNC than when using nasal continuous positive airway pressure (nCPAP), or nasal intermittent positive pressure ventilation. The rates of extubation failure during respiratory support were not different between patients who used HHHFNC and nCPAP. However, data from the use of HHHFNC as the initial respiratory support "after birth", particularly in extremely preterm infants, are lacking. Although the HHHFNC is efficacious and safe, large randomized controlled trials are needed before the HHHFNC can be considered an NIV standard, particularly for extremely preterm infants.

FUZZY SUPPORT VECTOR REGRESSION MODEL FOR THE CALCULATION OF THE COLLAPSE MOMENT FOR WALL-THINNED PIPES

  • Yang, Heon-Young;Na, Man-Gyun;Kim, Jin-Weon
    • Nuclear Engineering and Technology
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    • v.40 no.7
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    • pp.607-614
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    • 2008
  • Since pipes with wall-thinning defects can collapse at fluid pressure that are lower than expected, the collapse moment of wall-thinned pipes should be determined accurately for the safety of nuclear power plants. Wall-thinning defects, which are mostly found in pipe bends and elbows, are mainly caused by flow-accelerated corrosion. This lowers the failure pressure, load-carrying capacity, deformation ability, and fatigue resistance of pipe bends and elbows. This paper offers a support vector regression (SVR) model further enhanced with a fuzzy algorithm for calculation of the collapse moment and for evaluating the integrity of wall-thinned piping systems. The fuzzy support vector regression (FSVR) model is applied to numerical data obtained from finite element analyses of piping systems with wall-thinning defects. In this paper, three FSVR models are developed, respectively, for three data sets divided into extrados, intrados, and crown defects corresponding to three different defect locations. It is known that FSVR models are sufficiently accurate for an integrity evaluation of piping systems from laser or ultrasonic measurements of wall-thinning defects.