• Title/Summary/Keyword: Later pressure

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A Study on the Flame Structure and Stabilization in a Divergent Flow (확대관 흐름에 있어서 화염의 안정성 및 구조에 관한 연구)

  • 최병륜;이중성
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.2
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    • pp.512-518
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    • 1994
  • An experimental study is made on turbulent diffusion flames stabilized by a circular cylinder in a divergence flow. In this paper, stabilization characteristics and flame structure are examined by varying the divergence angle of duct and position of a circular cylinder. The fuel used is a commercial grade gaseous propane injected by two slit of rod. It is found that the positive pressure gradient greatly influences the eddy structure behind the rod. and that two different kinds of combustion patterns exist at the blowoff limit depending on the divergent angle of duct. They are distinguished by their wake structures: one associated with Karman vortex shedding, the other without it. Also, the blowoff velocity in the former is found to be higher than in the later.

An experimental study on the ignition characteristics of an air-assisted gasoline injector in a constant volume combustion chamber (정적 연소실 내에서의 2유체 가솔린 분사기의 착화 특성에 대한 실험적 연구)

  • 이용표;김승수
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.4
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    • pp.31-38
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    • 1992
  • The objective of this study is to determine the ignition feasibility of a single shot, air-assisted gasoline fuel injector operated in a constant volume combustion chamber under atmospheric condition. A number of parameters has been selected for this experiments, such as dwelling time, spark gap position(r,z), spark electrode geometry, supplied air and fuel masses and spray cone deflector angle. On-site visual inspection of the instantaneous flame glow was chosen as one way to judge the successful ignition. In addition, chamber pressure and occasional photography were mobilized as for data recording. It was clearly observed that there was an entrainment air-fuel mixture toward spray axis from the spray formation and its development later on. The optimum ignition conditions were found for those parameters given above.

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A study on Spray Characteristic of Fuel Injection Nozzle with Geometrical Shape Changes of Needle Valve (연료분사노즐의 니들밸브 형상변화에 따른 분무특성에 관한 연구)

  • 채재우
    • Journal of the korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.35-40
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    • 1987
  • The experimental study, using constant pressure injection system, is carried out to investigate the effect of the geometrical shape changes of the needle valve of the effective flow area, the spray angle and the Sauter's Mean Diameter according to needle valve lift for a pintle-type injection nozzle. The results are as follows: 1) With the increase of the needle valve lift, the effective flow area is increased, the spray angle is at first increased and later decreased, and the Sauter's Mean Diameter is decreased. 2) It is also shown that the spray angle is maximum at the rapidly increased region of the effective flow area.

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Congenital Pyloric Atresia with Junctional Epidermolysis Bullosa-a case report (수포성 표피박리증을 동반한 선천성 유문부폐쇄증 1예)

  • Cho, Ma-Hae;Han, Seok-Joo
    • Advances in pediatric surgery
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    • v.3 no.1
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    • pp.77-82
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    • 1997
  • The association of pyloric atresia and epidermolysis bullosa(EB) in newborn is rare and inheritant as an autosomal recessive trait. We report a newborn girl with pyloric atresia and epidermolysis bullosa. Blisters were noted on her skin at birth, especially in pressure-exposed area, and later on the oral mucosa. Junctional epidermolysis bullosa was confirmed by light microscopy and electron microscopy. Radiography revealed pyloric atresia. Segmental resection of 1.5 cm and gastroduodenostomy were carried out at 4 days of age. Protein loosing enteropathy developed after oral feeding. The frequency of episodes of nonscarred blisters and the severity and duration improved significantly with time. The protein loosing enteropathy was persistent, and at 1 year of age, her growth is markedly retarded.

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A Study on the Damage by Engine Backfire in the Mixer-type LPG Vehicles (Mixer-type LPG차량에서 엔진역화에 의한 차량 파손에 관한 연구)

  • Jeon, Kwang-Su;Choi, Sung-Eun;Chin, Young-Wook;Chung, Jin-Eun
    • Proceedings of the Safety Management and Science Conference
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    • 2009.11a
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    • pp.223-229
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    • 2009
  • The engine backfire leading to the damage to the intake system is observed in the mixer-type LPG engines. The hot spot flowing back into the intake manifold from the engine cylinder during the valve overlap period is known to give rise to the backfire. This backfire is known to be the main cause of the abrupt stop of the vehicle leading to the accidents on the streets. In this study, the cylinder pressure buildup at the later stage of combustion due to the prolonged burning is presumed to be the main cause of the backflow leading to the backfire. This is experimentally observed by creating the engine misfire using the ill-conditioned ignition systems.

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Application of genetic Algorithm to the Back Analysis of the Underground Excavation System (지하굴착의 역해석에 대한 유전알고리즘의 적용)

  • 장찬수;김수삼
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.65-84
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    • 2002
  • The Observational Method proposed by Terzaghi can be applied for the safe and economic construction projects where the exact prediction of the behavior of the structures is difficult as in the underground excavation. The method consists of measuring lateral displacement, ground settlement and axial force of supports in the earlier stage of the construction and back analysis technique to find the best fit design parameters such as earth pressure coefficient, subgrade reaction etc, which will minimize the gap between calculated displacement and measured displacement. With the results, more reliable prediction of the later stage can be obtained. In this study, back analysis programs using the Direct Method, based on the Hill Climbing Method were made and evaluated, and to overcome the limits of the method, Genetic Algorithm(GA) was applied and tested for the actual construction cases.

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Design of the recuperator for the gas turbine/fuel cell hybrid power generating system (가스터빈/연료전지 혼합발전 시스템의 열교환기 설계)

  • Kwak, Jae-Su;Yang, Soo-Seok;Lee, Dae-Sung
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.2105-2110
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    • 2004
  • Plate-fin type recuperators for the gas turbine/fuel cell hybrid power generating system were designed using commercial design software, MUSE. Heat transfer efficiency and total pressure drop in the recuperator were calculated to confirm required recuperator performance. Both counter flow and cross flow type plate-fin recuperators were designed. Results show that the counter flow type has higher efficiency and short core length, but the cross flow type is simpler to construct because the cross flow type does not need additional distributors. Two or three headers for the each recuperator core will be designed and tested to evaluate best header design. The designed recuperators and headers which will be designed later will be constructed, tested, and used in gas turbine/fuel cell hybrid power generating system.

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Status and Problems of Closed-Loop Supply Chain of Traditional Power Battery in China

  • Chen, Jinhui;Bayarsaikhan, Bayarsaikhan;Nam, Sootae;Jin, Chanyong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2021.10a
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    • pp.567-569
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    • 2021
  • The power battery supply chain in China currently lacks stable cooperation and effective information exchange. The competitive pressure brings about irregular recycling channels, reducing the operation and efficiency of the power battery supply chain. Besides, some regular power battery recycling enterprises fabricate data to obtain subsidies by taking advantage of the loopholes in the relevant policies of the state on recycling subsidies. Due to the high price of recycling in the black market, some regular enterprises resell the batteries recycled through regular channels, later purchasing the batteries with no utilization value to obtain the national recycling subsidies by cheating at the same time. Fig. 3 shows the present network structure of the tradi tional Chinese power battery closed-loop supply chain

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Smart Health Monitoring System (SHMS) An Enabling Technology for patient Care

  • Irfan Ali Kandhro;Asif Ali Wagan;Muhammad Abdul Aleem;Rasheeda Ali Hassan;Ali Abbas
    • International Journal of Computer Science & Network Security
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    • v.24 no.3
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    • pp.43-52
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    • 2024
  • Health Monitoring System is a sophisticating technology and another way to the normal/regular management of the health of the patient. This Health Monitoring Mobile Application is a contribution from our side to the public and to the overall health industry in Pakistan. With the help of Health mobile application, the users will be able to store their medical records, prescriptions and retrieve them later. The users can store and keep track of their vital readings (heart rate, blood pressure, fasting glucose, random glucose). The mobile application also shows hospitals that are nearby in case the user wants to avail of any medical help. An important feature of the application is the symptoms-based disease prediction, the user selects the symptoms which he has and then the application will name certain diseases that match those symptoms based on relevant algorithms. The major advances and issues have been discussed, and as well as potential tasks to health monitoring will be identified and evaluated.

Tension Pneumocephalus Secondary to Frontal Sinusotomy in a Dog

  • Seoyeoun Ji;Hyung-Kyu Chae;Yeon-Jung Hong
    • Journal of Veterinary Clinics
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    • v.41 no.4
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    • pp.223-227
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    • 2024
  • Air accumulation in the cranial cavity is referred to as pneumocephalus. Tension pneumocephalus is a neurosurgical emergency that can cause headaches, seizures, reduced consciousness, and even death owing to increased intracranial pressure. We report a case of tension pneumocephalus. The patient underwent a frontal sinusotomy for a mass invading the frontal sinus and nasal cavity. One month later, the patient was admitted to the emergency room with seizures and neurotic symptoms, and computed tomography (CT) revealed tension pneumocephalus with significant gas dilatation of both lateral ventricles. Prompt treatment of the dural defect resulted in the immediate improvement of neurological signs. A CT re-examination 1 week after surgery showed that the pneumocephalus had completely resolved. Tension pneumocephalus should be considered a potential complication in patients with worsening neurological signs after skull base surgery. An accurate diagnosis requires an understanding of imaging features and a high index of suspicion, and immediate intervention is essential.