• 제목/요약/키워드: effective clearance

검색결과 205건 처리시간 0.03초

A study on preventing the fall of skew and curved bridge decks by using rubber bearings

  • Ijima, Katsushi;Obiya, Hiroyuki;Aramaki, Gunji;Kawasaki, Noriaki
    • Structural Engineering and Mechanics
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    • 제12권4호
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    • pp.347-362
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    • 2001
  • The paper deals with preventing the collapse of by the means of supporting the bridges by rubber bearings and pedeck structures of skew and curved bridges during earthquakes, rmitting pounding between the decks and the abutments. Seismic response during pounding is characterized by various phenomena, such as the caging of bridge decks between abutments during an earthquake or decks popping out. These behaviors depend on only a small difference in seismic intensity. Regarding the global characteristics of a seismic response, smaller clearance between a deck and its abutments results in smaller impact damage of the abutments as well as lesser deformation of the rubber bearings. Similarly, smaller clearance between a deck and the side blocks results in smaller damage. The stiffnesses of the bearings and the stiffness ratio between them control the deck displacement. In short to medium length bridges, zero clearance between a deck and the abutments or the deck and the side blocks is the most effective way in preventing the deck from falling and limits the damage to the abutments or the side blocks.

DSA 전극에 의한 선박오폐수의 전해처리(I)-회분식 전해처리- (An Electrolytic Treatment of Shipboard Sewage by Using DSA Electrode (I) -Batch Electrolytic Treatment-)

  • 김인수;조권희;남청도
    • 해양환경안전학회지
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    • 제3권2호
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    • pp.69-76
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    • 1997
  • Each factor for the most effective electrolytic reaction in treating shipboard sewage was enhanced by means of batch electrolyitc reactor using DSA electrode. The effective clearance was 6mm and pH was 5-6. In such case, more than 20% of sea water concentration was needed to attain 90% of COD removal rate. The suspended solids was effectively removed by electro-floatation in proportion as charged current density. The nitrogen and posporous were effectively removed in the electrolytic device when mixed seawater.

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SM-2015의 혈중 알코올 분해 및 숙취 개선 효과 (Effects of SM-2015 on Blood Alcohol Clearance and Hangover)

  • 신선미;박선영;김태연
    • 대한한방내과학회지
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    • 제38권1호
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    • pp.20-31
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    • 2017
  • Objectives: This study investigated the effect of SM-2015 on blood alcohol clearance and hangover. We undertook this study to test whether SM-2015 is effective in decreasing blood alcohol concentration and preventing the symptoms of alcohol-induced hangover. Methods: Twenty healthy volunteers participated in this randomized crossover study. All participants were classified between an SM-2015 intake group (test group) and a non-intake group (control group). The primary outcome measure was the difference in blood alcohol concentration and hangover severity scores between the test and control groups. The secondary outcome measure was the difference in a liver function test (LFT) between the test and control groups. Results: After alcohol exposure, the sensitivity scores of blood alcohol concentration and hangover symptoms (sleepiness, dizziness, nausea, weakness, stomach pain, diarrhea, and concentration disorder) were significantly decreased in the SM-2015 intake group compared with the non-intake group. There were no differences in the LFT results between the SM-2015 intake group and the non-intake group. Conclusions: SM-2015 is effective in decreasing blood alcohol concentration and preventing the symptoms of alcohol-induced hangover. Larger studies are required to confirm these findings.

투석 및 관류에 의한 살충제 포스파미돈의 제거 효율 (Effect of Dialysis and Perfusion on Phosphamidon in vitro)

  • 홍세용;길효욱;양종오;이은영
    • 대한임상독성학회지
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    • 제3권1호
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    • pp.17-21
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    • 2005
  • Purfose: This study was to observe the phosphamidon reduction rate after haemoperfusion (HP) and Hemodialysis (HD) in vitro. Methods: We started off by measuring the clearance of HD and HP for the phosphamidon in vitro. Phosphamidon was measured hourly by High-pressure liquid chromatography. Results: Phosphamidon clearance was effectiveness in HP and HD. Phosphamidon reduction rate was no difference between HD and HP; $64\%$ versus $91.\%1$ at starting, $82.2\%$ versus $80.2\%$ at 1 hours, $82.2\%$ versus $73.8\%$ at 2 hours, $34.4\%$ versus $14.0\%$ at 3 hours, $14.1\%$ versus $27.4\%$ at 4 hours, $0\%$ versus $3.3\%$ at 5 hours. Conculsion: Extracorporeal elimination of phosphamidon is effective by hemoperfusio and hemodialysis in vitro. We suggest hemoperfusion may be effective in organophsphate intoxication patients.

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Clearance of Cervical Human Papillomavirus Infection by Topical Application of Curcumin and Curcumin Containing Polyherbal Cream: A Phase II Randomized Controlled Study

  • Basu, Partha;Dutta, Sankhadeep;Begum, Rakiba;Mittal, Srabani;Dutta, Paromita Das;Bharti, Alok Chandra;Panda, Chinmay Kumar;Biswas, Jaydip;Dey, Bindu;Talwar, Gursaran Prashad;Das, Bhudev Chandra
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권10호
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    • pp.5753-5759
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    • 2013
  • Curcumin and curcumin containing polyherbal preparations have demonstrated anti-microbial and antiviral properties in pre-clinical studies. Till date no therapeutic intervention has been proved to be effective and safe in clearing established cervical human papillomavirus (HPV) infection. The present study evaluated the efficacy of Basant polyherbal vaginal cream (containing extracts of curcumin, reetha, amla and aloe vera) and of curcumin vaginal capsules to eliminate HPV infection from cervix. Women were screened by Pap smear and HPV DNA test by PCR. HPV positive women without high grade cervical neoplasias (N=287) were randomized to four intervention arms to be treated with vaginal Basant cream, vaginal placebo cream, curcumin vaginal capsules and placebo vaginal capsules respectively. All subjects were instructed to use one application of the assigned formulation daily for 30 consecutive days except during menstruation and recalled within seven days of the last application for repeat HPV test, cytology and colposcopy. HPV clearance rate in Basant arm (87.7%) was significantly higher than the combined placebo arms (73.3%). Curcumin caused higher rate of clearance (81.3%) than placebo though the difference was not statistically significant. Vaginal irritation and itching, mostly mild to moderate, was significantly higher after Basant application. No serious adverse events were noted.

프로세스 압축기 틸팅패드 저널베어링의 비정상 고온거동 트러블슈팅 (Abnormal High-Temperature Behavior Troubleshooting of Process Compressor Tilting Pad Journal Bearing)

  • 이안성;이운실;최동훈
    • Tribology and Lubricants
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    • 제33권2호
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    • pp.37-44
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    • 2017
  • A DE-side LBP tilting pad journal bearing of a 1-stage overhung heat-pump compressor in a propylene process exhibited abnormal high-temperature behavior. Its temperature had been relatively high at $78^{\circ}C$ from the beginning of operation. In 2014, after three years of operation, it increased suddenly and reached $103^{\circ}C$. Installing a varnish removal equipment and others managed to stabilize the temperature at $95^{\circ}C$. We undertook a troubleshooting approach for reviewing the comprehensive status and integrity of the temperature design of the bearing. We performed lubrication and heat-balance analysis, based on the design engineering data and documents supplied by the OEM. For the base design data of DE-side TPJB, evaluating the effects of key design variables on bearing metal temperature showed that firstly, increasing the bearing clearance and supply oil flow-rate, and next, changing the oil type, and finally, increasing the machined pad clearance and offset, are more effective in reducing the bearing metal temperature. Furthermore, a clarification meeting with the OEM revealed that an incorrect decision had been made to decrease the bearing clearance to eliminate the SSV harshness issue, while not maintaining a sufficient oil flow-rate. We conducted a detailed retrofit design analysis, wherein we increased the oil flow-rate and bearing clearance by decreasing the preload. We predicted that the bearing temperature would decrease to $63^{\circ}C$ from $75.7^{\circ}C$ even at the rerate condition. Finally, after installing and operating a retrofit replacement bearing in 2015, the bearing temperature stabilized at a low temperature of $65^{\circ}C$. Currently (January. 2017), two year later, the bearing metal temperature remains at $65^{\circ}C$. Therefore, we can conclude that the abnormal high-temperature behavior of the bearing has been resolved completely.

적응형 유전알고리즘을 이용한 사용자 인터페이스 설계 방법 개발 (Development of an User Interface Design Method using Adaptive Genetic Algorithm)

  • 정기효
    • 대한산업공학회지
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    • 제38권3호
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    • pp.173-181
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    • 2012
  • The size and layout of user interface components need to be optimally designed in terms of reachability, visibility, clearance, and compatibility in order for efficient and effective use of products. The present study develops an ergonomic design method which optimizes the size and layout of user interface components using adaptive genetic algorithm. The developed design method determines a near-optimal design which maximizes the aggregated score of 4 ergonomic design criteria (reachability, visibility, clearance, and compatibility). The adaptive genetic algorithm used in the present study finds a near-optimum by automatically adjusting the key parameter (probability of mutation) of traditional genetic algorithm according to the characteristic of current solutions. Since the adaptive mechanism partially helps to overcome the local optimality problem, the probability of finding the near-optimum has been substantially improved. To evaluate the effectiveness of the developed design method, the present study applied it to the user interface design for a portable wireless communication radio.

플로우 터닝 공정에서의 성형성 연구 (Formability of Flow Turning Process)

  • 최석우;김승수;나경환;차달준
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2001년도 추계학술대회 논문집
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    • pp.195-199
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    • 2001
  • The flow turning process, an incremental forming process, is a cost-effective forming method for axi-symmetric intricate parts to net shape. However, the flow turning process shows a fairly complicated deformation, it is very difficult to obtain satisfactory results. Therefore extensive experimental and analytical research has not been carried out. In this study, an fundamental experiment was conducted to improve productivity with process parameters such as tool path, angle of roller holder($\alpha$), feed rate(v ) and comer radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to have an effect on spring back. The clearance was controlled in order to achieve the precision product which is comparable to deep drawing one. And also thickness and diameter distributions of a multistage cup obtained by flow turning process were observed and compared with those of a commercial product produced by conventional deep drawing.

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피스톤계 마찰 특성 (II) -실험적 연구- (Friction Characteristics of Piston Assembly (II) -Experiment-)

  • 조명래;하경표;김중수;오대윤;한동철
    • 대한기계학회논문집A
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    • 제27권1호
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    • pp.88-93
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    • 2003
  • The aim of this paper is to investigate the friction characteristics of piston assembly, which composed of ring pack and piston skirt. The friction force of piston assembly was measured by using the movable liner in the single cylinder engine, and the various parameters were tested. The friction force was suddenly increased at the expansion stroke due to higher cylinder pressure. The viscous friction was dominant at the mid stroke, but the boundary friction was dominant at the top and bottom dead centers. Through the experiment, we could validate previous theoretical study, and confirm that th e radial clearance and ring tension were very effective to reduce friction loss of piston assembly.

유압 피스톤 펌프의 피스톤과 실린더 사이의 윤활해석 (제1보:피스톤 형상에 의한 영향) (A Lubrication Analysis between the Piston and Cylinder in Hydraulic Piston Pumps Part 1: The effect of piston shape)

  • 박태조;전병수
    • Tribology and Lubricants
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    • 제14권1호
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    • pp.64-69
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    • 1998
  • A numerical analysis is carried out to study the effect of piston shape on the lubrication characteristics between the cylinder and piston in hydraulic piston pumps. The results showed that the shape of piston affect significantly the pressure distribution in the clearance, the lateral force acting on the piston and leakage flow through the clearance. Partially tapered piston is more effective than any other piston shapes because it reduces the possibility of hydraulic locking and improves the volumetric efficiency of the pump.