• 제목/요약/키워드: relief valve

검색결과 142건 처리시간 0.024초

편마비후 발생한 견수 증후군에 대한 성상신경절차단 (Stellate Ganglion Block for Shoulder Hand Syndrome following Hemiplegia)

  • 윤덕미;오흥근;유은숙;정소영
    • The Korean Journal of Pain
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    • 제6권2호
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    • pp.255-257
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    • 1993
  • Shoulder Hand Syndrome is used to describe painful disabilities of the upper extremity due to disturbances of sympathetic nerve supply. A 72 year old male developed hemiplegia on left side on the 5 days after open heart surgery of aortic valve replacement. Three months later, the patient complained of severe pain in the left upper extremity involving shoulder. The left hand showed swelling and flaccid paralysis. Thereafter the left stellate garglion block with 10 ml of l% lidocaine produced prompt pain relief. Thereafter the patient received 94 stellate ganglion block during 7 months which produced permanent remission of pain throughout a 1 year follow period. We recommand sympathetic block for of Shoulder Hand Syndrome following hemiplegia.

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ROSA/LSTF test and RELAP5 code analyses on PWR steam generator tube rupture accident with recovery actions

  • Takeda, Takeshi
    • Nuclear Engineering and Technology
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    • 제50권6호
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    • pp.981-988
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    • 2018
  • An experiment was performed for the OECD/NEA ROSA-2 Project with the large-scale test facility (LSTF), which simulated a steam generator tube rupture (SGTR) accident due to a double-ended guillotine break of one of steam generator (SG) U-tubes with operator recovery actions in a pressurized water reactor. The relief valve of broken SG opened three times after the start of intact SG secondary-side depressurization as the recovery action. Multi-dimensional phenomena specific to the SGTR accident appeared such as significant thermal stratification in a cold leg in broken loop especially during the operation of high-pressure injection (HPI) system. The RELAP5/MOD3.3 code overpredicted the broken SG secondary-side pressure after the start of the intact SG secondary-side depressurization, and failed to calculate the cold leg fluid temperature in broken loop. The combination of the number of the ruptured SG tubes and the HPI system operation difference was found to significantly affect the primary and SG secondary-side pressures through sensitivity analyses with the RELAP5 code.

하이드로 포밍 공정의 동특성 해석 및 시뮬레이션 (Dynamic Modeling and Simulation of a Hydro-forming Process)

  • 이우호;조형석
    • 한국정밀공학회지
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    • 제16권11호
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    • pp.122-132
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    • 1999
  • This study describes a dynamic model of the hydroforming process which is used for precision forming of sheet metals. To help the controller design for the control of the forming pressure needed for this process as well as to investigate the effect of system parameters on the dynamic behavior, dynamic modeling is performed with emphasis on hydraulic servo system which actuates the forming machine. Since the model contains several unknown parameters, these were estimated via a least square parameter identification method. Based upon the identified model, a series of simulations were performed for various operating conditions. The results were compared with those of the experiments to verify the validity of the proposed model. The comparison study shows that the proposed dynamic model can describe dynamic behavior of the forming pressure of the hydroforming process to desirable accuracy.

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PTA법에 의한 스텔라이트 12 합금 육성층의 특성에 미치는 전류의 영향 (The Effect of Current on Characteristics of Stellite 12 Alloy Overlayer by PTA Process)

  • 정병호;김무길;안용식;김민영;이성열
    • 동력기계공학회지
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    • 제5권3호
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    • pp.88-94
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    • 2001
  • Stellite 12 alloy-powders were overlaid on 410 stainless steel valve seat using plasma transferred arc(PTA) process. Variation of the microstructure, hardness, wear and corrosion of overlaid deposit with current change was investigated. The deposit showed hypoeutectic microstructure, which was consisted of primary cobalt dendrite and networked $M_7C_3$ type eutectic carbides. As current increased, the amount of eutectic carbide decreased and its dendritic secondary arm spacing increased. Hardness of the deposit was decreased with increase of current. Stress relief heat treatment at $600^{\circ}C$ for two hours resulted in slight increase of hardness in the deposit and showed uniform hardness distribution in base metal without any hardened layer in HAZ. Specific wear decreased with increase of sliding distance. The deposit of high hardness with a lot of eutectic carbide showed relatively low specific wear. Initial corrosion current density of the deposit in 0.1N sulfuric acid was lower than those of 410 stainless steel, and showed a little variation with PTA current.

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흉쇄관절 탈구에 대한 경피적 강선고정술후 발생한 동정맥루 -1례 보고- (Arteriovenous Fistula After Percutaneous Pinning of Sternocalvicular Joint - 1 case report -)

  • 성후식;하종곤
    • Journal of Chest Surgery
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    • 제31권6호
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    • pp.615-618
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    • 1998
  • 체 동-정맥루는 보기 드물지만 과운동성 순환을 일으켜, 미발견시 울혈성 심부전증까지 야기시키는 원인질환중 하나이다. 본 교실에서는 아주 희귀한 후천성 동-정맥루 1례를 경험하였다. 환자는 61세 여자로 우측 흉쇄관절 탈구에 대한 경피적 강선고정술후 울혈성 심부전증을 나타내었다. 수술은 대동맥과 무명정맥사이에 발생한 동-정맥루를 폐쇄하고, 심한 삼첨판 폐쇄부전에 대한 삼첨판 판륜성형술을 동시에 시행하였다. 술후 환자는 증상으로부터 완전히 회복되어 퇴원하였으며, 약 2년 6개월 추적기간중 상태 양호하다.

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선천성 심장기형에 대한 2차수술로서의 개심술 (Reoperation for congenital heart disease)

  • 안혁;성숙환;김용진;노준량;서경필
    • Journal of Chest Surgery
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    • 제19권2호
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    • pp.280-287
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    • 1986
  • Between March 1978 and August 1985, 29 cases at various congenital heart diseases were reoperated because of remnant shunt of residual anomalies at Seoul National University Hospital. They were consisted of 10 cases of Tetralogy, 4 simple VSD, 6 complicated VSD. 3 partial ECD, and 5 other rare congenital anomalies. The interval between the initial and the second procedure ranged from 1 day to 122 months [mean; 26.9 months]. In 4 cases of them, the second procedure was done during initial hospitalization within 3 weeks post-operatively. The primary operation intended to be corrective surgery except four whose primary operation was palliative or exploratory one even though it was done with extracorporeal circulation. The indication for second operation was mainly residual shunt or valvular obstruction due to patch detachment or inadequate relief of stenotic lesion. Others were paravalvular leak, valvuloplasty failure, prosthetic valve failure, and inadequate primary diagnosis. Four patients were dead [14.3%]; three complicated VSD`s and one Tetralogy. There were 7 cases of nonfatal complication with subsequent improvement except one [diffuse cerebral dysfunction].

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고식적 목적 혹은 Fontan 수술 전단계로서 시행한 양방향성 상공정맥 폐동맥 단락술의 조기 임상 결과 (Bidirectional Cavopulmonary Shunt Operations as Palliation or Pre-Fontan Stage Operation - Early Results -)

  • 한재진
    • Journal of Chest Surgery
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    • 제25권4호
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    • pp.406-411
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    • 1992
  • Thirty-four patients were received bidirectional cavopulmonary shunt[BCPS] from Aug. 1989 to Apr. 1991 at Sejong General Hospital, Puchon, Korea. Their ages were from 43 days to 21 years old with 19 cases of infant, 10 from 1 to 5 years old and 5 cases above 6 years old. Their diagnoses were as follows: 13 cases with uni-ventricular heart, 9 tricuspid atresia, 6 double outlet of right ventricle, 4 pulmonary atresia with intact ventricular septum, and 2 transposition of great arteries with pulmonary stenosis. Among them, 10 patients had received other palliative operations before. The BCPS operations were performed under the cardiopulmonary bypass and 10 patients who had bilateral superior vena cava received bilateral BCPS. Other associated procedures were 9 cases of takedown of Blalock-Taussig shunt, 3 pulmonary artery angioplasty, 1 unifocalization, 1 repair of total anomalous pulmonary venous return, 1 Damus procedure, 1 relief of sub-aortic stenosis, 1 right ventricular outflow tract reconstruction and one case of tricuspid valve obliteration. There were 3 operative deaths[8.8%] and two late deaths. The remainders show good postoperative state and their oxygen saturation was increased significantly. Conclusively, the bidirectional cavopulmonary shunt is very effective and safe palliative or pre-Fontan stage operation for the many complex congenital anomalies with low pulmonary blood flow especially for the patients who have the risk of Fontan repair.

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영광3,4호기 안전감압계통 추가설비 설계최적화를 위한 시스템엔지니어링 적용연구 (Systems Engineering Approach to Reengineering of YGN 3&4 Safety Depressurization System Retrofit Design)

  • 최문원;김규완;한기인
    • 시스템엔지니어링학술지
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    • 제11권1호
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    • pp.1-7
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    • 2015
  • The purpose of this paper is to present the results of reengineering of the YGN 3&4 (Yonggwang Nuclear Power Plant, Units 3&4) SDS (Safety Depressurization System) retrofit design and to make recommendations for the improvement in design and design procedure implementing the Systems Engineering (SE) process. YGN 3&4 is a basic model for OPR1000 (the Korean standard 1000 MWe plant). The basic model, herein, represents the reference plant for the OPR1000 development. In the middle of the YGN 3&4 construction, the Korean Nuclear Regulatory Body requested a retrofit of this plant with a means to rapidly depressurize the plant in conformance with a severe accident mitigation requirement. For the reengineering of the SDS in YGN 3&4, V-model and functional and physical architectures have been developed. A SE decision making method has been used for the selection of SDS valves. Finally, recommendations have been made to improve OPR1000 design for the improved operation and enhanced safety.

대동맥판상부협착증: 치험 3례 (Supravalvular Aortic Stenosis - Report of 3 cases -)

  • 전예지
    • Journal of Chest Surgery
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    • 제24권3호
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    • pp.280-286
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    • 1991
  • Supravalvular aortic stenosis may be defined as an obstructive congenital deformity of the ascending aorta which originates just distal to the level of the origins of the coronary arteries It may be localized or diffuse. Enlargement of the aorta with a diamond-shaped patch of the noncoronary sinus of Valsalva was reported in 1961 by McGoon and associates But this reconstruction is asymmetric and the aortic obstruction may remain. In 1977, Dotty and associates reported the extended aortoplasty, the supravalvular ring was incised at two points in the noncoronary and in the right coronary sinuses of Valsalva closed with a tubular Dacron prosthesis of inverted Y-shape tailored to reconstruct the aorta We experienced three cases of the supravalvular aortic stenosis. The 11-year-old female and 4-year-old male with localized supravalvular aortic stenosis in William`s syndrome were operated with an inverted Y-shaped aortotomy toward the non-coronary sinus and the right coronary sinus and closed with "Hemashield`s collagen impregnated Dacron" tube graft, fashioned into "pantaloon" form patch. The 12-year-old male with localized supravalvular aortic stenosis and mitral insufficiency in William`s syndrome were operated with same procedure as two other patient above-mentioned for relief of supravalvular aortic stenosis and with mitral valve replacement. Postoperative course has been good.ourse has been good.

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Shape and Orifice Optimization of Airbag Systems for UAV Parachute Landing

  • Alizadeh, Masoud;Sedaghat, Ahmad;Kargar, Ebrahim
    • International Journal of Aeronautical and Space Sciences
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    • 제15권3호
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    • pp.335-343
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    • 2014
  • An airbag is an important safety system and is well known as a safety system in cars during an accident. Airbag systems are also used as a shock absorber for UAVs to assist with rapid parachute landings. In this paper, the dynamics and gas dynamics of five airbag shapes, cylindrical, semi-cylindrical, cubic, and two truncated pyramids, were modelled and simulated under conditions of impact acceleration lower than $4m/s^2$ to avoid damage to the UAV. First, the responses of the present modelling were compared and validated against airbag test results under the same conditions. Second, for each airbag shape under the same conditions, the responses in terms of pressure, acceleration, and emerging velocity were investigated. Third, the performance of a pressure relief valve is compared with a fixed-area orifice implemented in the air bag. For each airbag shape under the same conditions, the optimum area of the fixed orifice was determined. By examining the response of pressure and acceleration of the airbag, the optimum shape of the airbag and the venting system is suggested.