• 제목/요약/키워드: Adverse conditions

검색결과 545건 처리시간 0.033초

휠 베어링용 밀봉 시일 설계를 위한 시일 립의 밀착력 예측 (Prediction of the Reaction Force for Seal Lip Design with Wheel Bearing Unit)

  • 김기훈;유영면;임종순;이상훈
    • 한국자동차공학회논문집
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    • 제9권5호
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    • pp.165-172
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    • 2001
  • Wheel bearing units were almost exclusively used for car front wheel, where the two ball rows are directly side by side with integrated rubber seal. The seal is of important for wheel bearing units due to the adverse environmental conditions with mud and splash water. The seal of wheel bearing units was designed to have geometry with multi lips, which elastic lip contacts and deforms with bearing. The equation of reaction force for deformed lip as cantilever beam was previously used for seal lip design. But it's result was not useful because deflection of the beam differs from lip's. In this study, deformed shape of the lip was assumed to and order function which is more similar to lip deformation and made the equation for reaction force prediction. The Reaction forces from each other equations were compared with results by FEA to prove usefulness of new equation.

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선박탑재용 종합내항성능 평가시스템 개발을 위한 기초적 연구 (A basic study for the development of Integrated Seakeeping Performance Evaluation System on board the ship)

  • 조익순;이충로;김순갑
    • 한국항해학회지
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    • 제24권3호
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    • pp.103-111
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    • 2000
  • From a ship's safe operation point of view, it is very important to estimate the navigational safety in a seaway. The seakeeping performance can be defined as the ability of a ship to go to sea, and to accomplish its missions successfully and safely even in adverse environmental conditions. There are several factors presently adopted for evaluating seakeeping performance. But a hardware of the system considering all these factors has not been developed since some of them can not be measured by sensors. In this paper, a synthetic method of evaluating navigational safety is developed by measuring the vertical and lateral acceleration. An experiment by using real measuring carried out on board the T/S 'HANNARA' The equipment was measured every 4 hours for more than 30 minutes the acceleration by accelerometer, analyzed its acceleration values and calculated navigational dangerousness. As the results of this on board experiment, the system is carried conviction to be useful as evaluating seakeeping performance.

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지역자원 순환형 유기한우의 경영모델 (A Management Model for Korean Organic Beef Cattle Farming using Regional Resources)

  • 허승욱;김호
    • 한국유기농업학회지
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    • 제16권1호
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    • pp.1-19
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    • 2008
  • Producing Korean organic beef cattle costs a great deal because it needs breeding conditions like the organic feed, an uncontaminated breeding farm and so on. So the price of Korean organic beef (KOB) is more expensive than that of Korean general beef (KGB). To overcome this adverse price condition, a case production organization in Asan will choose direct marketing routes for consumers or the shop under direct management of the organization, or franchise shops. As a result, these marketing routes are expected to narrow the price gap between KOB and KGB. And consumers will accept the price of KOB if quality of KOB is very high level, for example the first grade++.

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Characterization of Benzoate Degradation via ortho-Cleavage by Streptomyces setonii

  • An, Hae-Reun;Park, Hyun-Joo;Kim, Eung-Soo
    • Journal of Microbiology and Biotechnology
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    • 제10권1호
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    • pp.111-114
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    • 2000
  • Streptomyces are widespread in nature and play a very important role in the biosynthesis as well as biodegradation of natural and unnatural aromatic compounds. Both qualitatively and quantitatively through TLC and UV spectrophotometric assays, it was observed that the thermophilic soil bacteria S. setonii (ATCC 39116), which can utilize a benzoate as a sole carbon and energy source in a minimal liquid culture, was not very sensitive to the benzoate concentation and to the culture conditions such as the pH and temperature. The in vitro conversion of a catechol to a cis, cis-muconic acid by a crude S. setonii lysate implies that the aromatic ring cleavage by S. setonii is initiated by a thermostable catechol-1,2-dioxygenase, the key enzyme in the ortho-cleavage pathway of aromatic compound biodegradation. Unlike non-degrading S. lividans, S.setonii was also highly resistant to other similar hazardous aromatic compounds, exhibiting almost no adverse effect on its growth in a complex liquid culture.

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임상가를 위한 특집 2 - 중증 지적 장애인을 위한 효과적인 치과치료 (Dental treatments for patients with severe mental challenges)

  • 장주혜
    • 대한치과의사협회지
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    • 제49권12호
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    • pp.739-748
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    • 2011
  • Patients with severe mental challenges are often subjected to extensive dental problems. Their impaired communication and lack of cooperation unable to receive timely dental treatments, which deteriorates their adverse oral conditions. In spite of a limited time frame, well-planned comprehensive treatments can be delivered in an one-day operation setting under general anesthesia. This multidisciplinary treatment regimen primarily comprises of single-visit endodontics, direct bonded restoration, periodontal treatment, and surgical extraction. Further, one or two additional visits for prosthetic procedures are able to accomplish functional reestablishment and esthetic enhancement. This article discusses on clinical managements for severely mentally challenged patients under a single-day operation.

고속전철용 와전류제동장치 구동에 관한 연구 (A Study on Eddy Current Brake For a High-speed Railway Train)

  • 류홍제;우명호;김종수;강경호;강도현;임근희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1999년도 하계학술대회 논문집 F
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    • pp.2745-2747
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    • 1999
  • Recently, the eddy current braking system has an advantage as the high speed railway train is developed. Because it is independent on wheel-rail coefficient of adhesion and it can be used in adverse weather conditions by reason of non-acting on wheels. In this paper we designed down-scaled eddy current brake model and developed control algorithm to generate constant braking torque. Our algorithm is verified through experiments to generate constant torque.

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선대칭 형태에 있어서의 베이스 압력의 예측 (Prediction on The Base Pressure for An Axisymmetric Body)

  • 백두성;한영출
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집B
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    • pp.491-496
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    • 2000
  • The physics of the flow field surrounding an engine nacelle afterbody is very complex. A high pressure jet from the nozzle interacts with the external flow and causes upstream influence on the afterbody surface field. At certain conditions, the nozzle boundary layer can separate, either by shock wave interaction or by adverse pressure gradient effect, resulting in a severe drag penalty. Furthermore, a finite afterbody base implies a recirculating flow region. A flow modeling method has been developed to analyze the flow in the annular base(rear-facing surface) of a circular engine nacelle flying at subsonic speed but with a supersonic exhause jet. Real values of exhaust gas properties and temperature are included.

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Optimal oxygen saturation in premature infants

  • Chang, Mea-Young
    • Clinical and Experimental Pediatrics
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    • 제54권9호
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    • pp.359-362
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    • 2011
  • There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation ($SpO_2$) is 90 to 93% with an intermittent review of the correlation between $SpO_2$ and the partial pressure of arterial oxygen tension ($PaO_2$). Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

Antioxidant effect of myricetin with other antioxidants, taurine and $\beta$-carotene on mouse melanoma cell

  • Yu, Ji-Sun;Kim, An-Keun
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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    • pp.69-69
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    • 2003
  • There are now increasing evidences that free radicals and reactive oxygen species are involved in a variety of pathological events. Reactive Oxygen Species (ROS) are produced during normal cellular function. ROS lead to lipid peroxidation, massive protein oxdiation and degradation. Under normal conditions, antioxidant are substnaces that either directly or indirectly protect cell against adverse effect of ROS. several biologically important compound include ${\beta}$-carotene, taruine and flavonoids reported have antioxidant function. The various antioxidant either scavange superoxide and free radicals or stimulate the detoxification mechanisms within cells resulting in increased detoxification of free radicals formation and thus in prevention of many pathophysiologic processes. This study carried out to investigate the antioxidant activity of flavonoids, myricetin with other antioxidants, ${\beta}$-carotene and taurine on B16Fl0. In order to investigate the efficacy of antioxidant activity, we measured cell viability, antioxidant enzyme activity (SOD, GPX, CAT) and intracellular reactive oxygen intermediate (ROI). In this results, we show that these flavonoids with other antioxidant substrates are increased antioxidant activity level.

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Research on the Safety Improvement Method for the Company' s RAMS Management Business and Public Infrastructure

  • 이종범;조재립
    • 한국품질경영학회:학술대회논문집
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    • 한국품질경영학회 2010년도 춘계학술대회
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    • pp.254-261
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    • 2010
  • The increase in hazard level is attributed to the industrial hazard environment; complete national environmental hazards to human health include climate change. The damage level in Korea from 1993 to 2009 has exceeded the Increase In adverse environmental conditions. Priority areas of concern will include those risks that are most likely to occur and are expensive when they do take place such as accident or injury at a community pool. Therefore, in this paper, we suggest the System Engineering method for application to the railway RAMS. Recently, the requirement of high-integrity level of infrastructure has been deemed important. The systems level approach is defined through the assessment of the RAMS interactions between elements of complex system applications.

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