• 제목/요약/키워드: Intake 3-Valve

검색결과 78건 처리시간 0.027초

Cherepnov 송수기에 대한 배수제어방식의 실험적 특성 (Experimental Characteristic of Drain Control to Cherepnov Water Lifter)

  • 박성천;이강일
    • 한국농공학회지
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    • 제39권6호
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    • pp.67-79
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    • 1997
  • The perpose of this study was to suggest the experimental characteristic of the Cherepnov Water Lifter following the drain mode. The Cherepnov Water Lifter(CWL), which is powered by the potential energy of water, can be set to operate automatically when the water m a tank is drained. In this study, a CWL is constructed in the valve drain controlling mode(VCM) and the siphon drain controlling mode(SCM), and a pressure transducer is installed. It was found that, in the VCM, intake flow volume is proportional to both delivery flow volume and drain flow volume. In the SCM, intake flow volume is proportional to drain flow volume, and the average delivery rate is proportional to both efficiency and the water utilization ratio. Also, in the VCM, the water utilization ratio is 35~49%, efficiency is 62~9O%, average delivery rate is 12.8~81.2$cm^3$/s, and the average drain rate is 14.O~91.5c$cm^3$/s. On the contrary in the SCM, the water utilization ratio is 1.7~38%, efficiency is 3~58%, average delivery rate is 3.1 ~69.2$cm^3$/s, and the average drain rate is shown as 114.5~ 183$cm^3$/s. As a result of the water utilization ratio, efficiency, average delivery rate, and average drain rate are compared, the VCM is found to be superior and the more economical mode. However, the VCM requires manpower and electricity to operate the electronic machinery involved, while the SCM requires no manpower or electricity at all. An economic evaluation of these differences will be necessary in the future. Also, in the SCM, studies to improve water utilization ratio and efficiency, to find the optimum height of the siphon for decreasing the average drain rate, and to determine the radius of curvature of throat have to be conducted in advance, since a large flow rate is drained during the priming action of the siphon.

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정상유동 장치에서 유동 특성 평가 방법에 대한 연구(3) - 유속분포(1) (Study on Evaluation Method of Flow Characteristics in Steady Flow Bench(3) - Velocity Profile(1))

  • 박찬준;성재용;엄인용
    • 한국자동차공학회논문집
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    • 제24권2호
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    • pp.169-182
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    • 2016
  • This paper is the third investigation on the evaluation methods of flow characteristics in a steady flow bench. In the previous works, several assumptions used in the steady flow bench were examined and the flow characteristics were estimated both by the conventional impulse swirl meter and a particle image velocimetry at 1.75B position. From these works, it was concluded that the assumption of the solid rotation might cause serious problems and both of the eccentricity and the velocity profile distort the flow characteristics when using the ISM at 1.75B plane. Therefore, the understanding of the detail velocity profiles is very important to keep discussing the issues about the steady flow evaluation method. For this purpose, the planar velocity profiles were measure at 1.75B position by particle image velocimetry and the characteristics were examined according to the valve angles and lifts. The results show that the planar velocity profiles of 11, 16, $21^{\circ}$ valve angle heads according to the lift are similar to each other, however, that of $26^{\circ}$ angle is an exceptional case in the all aspects. In addition, the swirl behaviors are not apparent up to 6~8 mm lift under the $21^{\circ}$ angle and somewhat arranged motions are observed over the whole plane near the highest lift. At this point, the narrower the angle, the lower the lift at which the swirl motions become clear. On the other hands, when the angle is $26^{\circ}$, the center of swirl is always farthest from the cylinder center and only the indistinct swirl is observed even if at the highest lift. Also, all the swirl centers are quite apart from the cylinder center so that the effect of eccentricity may not be negligible at 1.75B regardless the valve angle. Related to the tangential velocity along with the radial direction, the bands of the velocity distribution are very wide and the mean velocities of cylinder center basis are lower than the velocity which is assumed in the ISM evaluation. Lastly, the mean tangential velocity profiles of swirl center basis are sometimes higher than that of ISM-assumed up to 0.6 non-dimensional distance less than 6mm lift, however, as the lift increases the profiles are different according to the angles and profile $11^{\circ}$ is the most closed to the ideal profile. Consequently, the real velocity profile is far from the assumption of ISM evaluation.

자동차용 LPG 엔진의 점화플러그 장착 부 손상, 점화시기 조정불량, 흡입밸브 부 이물질유입 고장사례 연구 (Study for Failure Examples Involved to Spark Plug Assembling Part Damage, Timing Maladjustment and Alien Substance Insertion in Intake Valve Part on LPG Vehicle Engine)

  • 이일권;국창호;함성훈;김성모;황한섭;정동화;문학훈;이정호
    • 한국가스학회지
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    • 제25권2호
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    • pp.22-27
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    • 2021
  • 이 논문은 LPG 자동차용 엔진의 고장사례를 연구하여 자동차 생산에 활용함이 목적이다. 첫번째 사례는 엔진의 실린더헤드를 분해하여 확인한 결과 실린더 헤드의 점화플러그가 조립되는 나사부 마멸때문에 점화플러그의 불꽃이 누설되어 출력이 떨어지면서 엔진의 부조화 현상이 가끔 유발되는 것을 발견하였다.. 두 번째 사례는 캠샤프트의 위치와 크랭크 샤프트 위치를 맞춘 타이밍 마크가 0.5칸 틀어져 엔진의 부조화 현상이 발생된 것을 확인되었다. 세 번째 사례는 실린더 헤드를 분해하여 확인한 결과, 실린더 헤드에 제거되지 못한 이물질이 3번 흡기포트에서 공기 흐름에 따라 이동하다가 흡기밸브의 닫힘시기를 원활하지 못하여 하여 고장이 발생된 것을 확인하였다. 따라서, 자동차 관리자는 철저하게 점검해야 하고, 자동차 생산자는 철저한 품질확보를 통해 고장의 원인을 제거해야 할 것으로 판단된다.

A case of anemia caused by combined vitamin B12 and iron deficiency manifesting as short stature and delayed puberty

  • Song, Seung-Min;Bae, Keun-Wook;Yoon, Hoi-Soo;Im, Ho-Joon;Seo, Jong-Jin
    • Clinical and Experimental Pediatrics
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    • 제53권5호
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    • pp.661-665
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    • 2010
  • Anemia caused by vitamin B12 deficiency resulting from inadequate dietary intake is rare in children in the modern era because of improvements in nutritional status. However, such anemia can be caused by decreased ingestion or impaired absorption and/or utilization of vitamin B12. We report the case of an 18-year-old man with short stature, prepubertal sexual maturation, exertional dyspnea, and severe anemia with a hemoglobin level of 3.3 g/dL. He had a history of small bowel resection from 50 cm below the Treitz ligament to 5 cm above the ileocecal valve necessitated by midgut volvulus in the neonatal period. Laboratory tests showed deficiencies of both vitamin B12 and iron. A bone marrow examination revealed dyserythropoiesis and low levels of hemosiderin particles, and a cytogenetic study disclosed a normal karyotype. After treatment with parenteral vitamin B12 and elemental iron, both anemia and growth showed gradual improvement. This is a rare case that presented with short stature and delayed puberty caused by nutritional deficiency anemia in Korea.

전자제어분사 방식 소형엔진의 1차원 성능 모델 개발 (One Dimensional Simulation Model Development of the EFI Small Engine)

  • 염경민;박성영
    • 한국산학기술학회논문지
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    • 제12권4호
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    • pp.1502-1508
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    • 2011
  • 본 연구에서는 전자제어 분사방식 소형엔진의 모델을 개발하기 위하여 기존 소형엔진의 제원을 바탕으로 1차원 모델을 구성하였다. 새롭게 구성된 모델의 성능해석을 수행하고 이를 실험결과와 분석하여 모델의 타당성을 확인하였다. 1차원 성능 모델의 토크 및 출력 해석결과는 실험결과와 3%이내의 오차를 보였으며, 소형엔진의 토크 및 출력 특성을 우수하게 예측하고 있다. 소형 엔진의 성능향상을 위해 엔진의 흡입성능에 미치는 성능인자의 영향력을 분석하였다.

영양부족 환자의 조기발견을 위한 선별검사의 적용 및 효용성 평가 (Application and Efficacy Evaluation of Nutritional Screening Tool)

  • 남궁환
    • 한국건강관리협회지
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    • 제4권1호
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    • pp.1-11
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    • 2006
  • "본 논문은 대한외과학회지 2006년 제70권제1호에 실렸던 논문으로 대한외과학회 편집위원회 승인을 득하고 본 협회지에 게재함. Purpose: Malnutrition has been frequently reported for patients on their admission to the hospital and it has been associated with an increase in morbidity, mortality and the length of the hospital stay. Although a number of screening tools have been developed to identify those patients at risk for malnutrition, there is no' gold standard' for defining malnutrition and the malnourished patients remain largely unrecognized. The aim of this study is to evaluate the efficacy of a nutritional screening tool for use in Dankook University Hospital. Methods Nutritional evaluation was performed for 53 patients who were admitted to the department of surgery and internal medicine between October and December 2004. The screening tool was completed by the ward nurse and the nutritional support team nurse on the same patients within24 hours of admission. The nutritional support team nurse performed the full assessment. The screening sheet included 4 questions regarding body mass index, recent unintentional weight loss, food intake and disease severity. Each answer was scored and a total of 5 was tested as the criterion fey malnutrition. The full assessment included current body weight, recent weight loss, triceps skinfold thickness, mid-arm muscle circumference, serum albumin)in and total lymphocyte count. Malnutrition was defined by 3 or more values below the reference values. The reliability of the screening tool was assessed using kappa statistic. Sensitivity, specificity and accuracy were calculated to evaluate the validity of the screening tool. The receiver operating characteristic(ROC) curve was drawn to choose a cutoff valve that maximizes sensitivity and specificity. Results' The level of agreement between the ward nurse and the NST nurse was good for BMI and food intake and moderate for weight loss and disease severity. The full assessment identified7 patients(13.2%) as malnourished. The screening sheet had a sensitivity of 86% and a specificity of 80%. According to the ROC curve, a score of 5 points provided the best validity. Conclusion The nutritional screening tool is reliable when completed by different observers and it is valid for nutritional assessment.

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알루미나이징 강의 마모특성에 관한 연구 ( 1 ) - Rolling-Sliding 마찰의 초기마모영역을 중심으로 - (A Study on the Wear Characteristics of Aluminizing Steel ( 1 ) - Wear in Run-in Period on Rolling-Sliding Contact -)

  • 이규용
    • 수산해양기술연구
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    • 제14권2호
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    • pp.69-78
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    • 1978
  • 알루미나이징강에 대하여 초기마모영역에서 rolling-sliding 마모시험을 한 결과를 요약하면 다음과 같다. 1) 2차 확산재의 내마모성이 가장 우수하고 처녀재에 비하여 저응력 레벨에서 약 18%, 고응력에서 약 40%의 마모감소를 나타낸다. 2) 2차 확산재는 피복층과 합금층 경계부근의 공공생성으로 인하여 예상보다 내마모성이 낮다. 3) 알루미나이징강의 rolling-sliding 접촉에 의한 마모파양의 형태는 spalling 이며 spalling crack은 합금속의 경계부근에서 발생한다.

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The Survey of Dentists: Updated Knowledge about Basic Life support and Experiences of Dental Emergency in Korea

  • Cho, Kyoung-Ah;Kim, Hyuk;Lee, Brian Seonghwa;Kwon, Woon-Yong;Kim, Mi-Seon;Seo, Kwang-Suk;Kim, Hyun-Jeong
    • 대한치과마취과학회지
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    • 제14권1호
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    • pp.17-27
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    • 2014
  • Background: Various medical emergency situations can occur during dental practices. Cardiac arrest is known to comprise approximately 1% of emergency situation. Thus, it is necessary for dentists to be able to perform cardiopulmonary resuscitation (CPR) to increase the chance of saving patient's life in emergency situation. In this paper, we conducted a survey study to evaluate to what extent dentists actually understood CPR practice and if they had experience in handling emergency situations in practice. Method: The survey was done for members of the Korean Dental Society of Anesthesiology (KDSA), who had great interest in CPR and for whom survey-by-mail was convenient. We had selected 472 members of the KDSA with a dental license and whose office address and contact information were appropriate, and sent them a survey questionnaire by mail asking about the degree of their CPR understanding and if they had experience of handling emergency questions before. Statistical analyses -frequency analysis, chi-square test, ANOVA, and so on- were performed by use of IBM SPSS Statistics 19 for each question. Result: Among 472 people, 181 responded (38.4% response rate). Among the respondents were 134 male and 47 female dentists. Their average age was $40.4{\pm}8.4$. In terms of practice type, there were 123 private practitioners (68.0%), 20 professors (11.0%), 16 dentists-in-service (8.8%), 13 residents (specialist training) (7.2%) and 9 military doctors (5%). There were 125 dentists (69.1%) who were specialists or receiving training to be specialist, most of whom were oral surgeon (57, 31.5%) and pediatric dentists (56, 30.9%). There were 153 people (85.0%) who received CPR training before, and 65 of them (35.9%) were receiving regular training. When asked about the ratio of chest pressure vs mouth-to-mouth respiration when conducting CPR, 107 people (59.1%) answered 30:2. However, only 27.1% of them answered correctly for a question regarding CPR stages, C(Circulation)- A(Airway)- B(Breathing)- D(Defibrillation), which was defined in revised 2010 CPR practice guideline. Dentists who had experience of handling emergency situations in their practice were 119 (65.6%). The kinds of emergency situations they experienced were syncope (68, 37.6%), allergic reactions to local anesthetic (44, 24.3%), hyperventilation (43, 23.8%), seizure (25, 13.8%), hypoglycemia (15, 8.3%), breathing difficulty (14, 7.8%), cardiac arrest (11, 6.1%), airway obstruction (6, 3.3%), intake of foreign material and angina pectoris (4, 2.2%), in order of frequency. Most respondents answered that they handled the situation appropriately under the given emergency situation. In terms of emergency equipment they had blood pressure device (70.2%), pulse oximetry (69.6%), Bag-Valve-Mask (56.9%), emergency medicine (41.4%), intubation kit (29.8%), automated external defibrillator (23.2%), suction kit (19.3%) and 12 people (6.6%) did not have any equipment. In terms of confidence in handling emergency situation, with 1-10 point scale, their response was $4.86{\pm}2.41$ points. The average point of those who received regular training was $5.92{\pm}2.20$, while those who did not was $4.29{\pm}2.29$ points (P<0.001) Conclusion: The result showed they had good knowledge of CPR but the information they had was not up-to-date. Also, they were frequently exposed to the risk of emergency situation during their dental practice but the level of confidence in handling the emergency situation was intermediate. Therefore, regular training of CPR to prepare them for handling emergency situation is deemed necessary.