• 한국정밀공학회지
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• 제18권4호
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• pp.190-196
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• 2001

The naval vessel must moves rolling, pitching, yawing by wave when it runs in ocean. Some narrow beam antenna needed position compensation by stabilizer or gimbal for best performance. This paper presents the precision position control for heavy weight(130kg) in roll and pitch direction. Generally it's called for gimbal. This gimbal uses P-I controller, and it's driven by linear actuator and servo motor. This gimbal gets ship's gyro signal and synchro, which have the absolute angle value. Some other similar equipments are driven by huge hydraulic power, but this gimbal is driven by small servo motor. This control loop gets the following procedure repeatedly; reading ship gyro and gimbal synchro, calculating compensated error and control output, driving motor and actuator The performance of gimbal system was satisfied.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2005년도 추계학술발표논문집
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• pp.127-139
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• 2005

It is very difficult to export the fresh agricultural products to long distant countries such as America and EU without any damage. Fresh exporting products would be met very hazardous environments such as hot and cold weather, heavy trembles with rolling and pitching. Therefore, care should be taken on tight fastening the products inside the container and keeping the designated temperature and relative humidity. The physical strength of outer box should be applied differently because each agricultural product has its own character for packaging. There have been many agricultural products researches for export packaging to the U.S.A. so far. However they have never got desirable results which enough to apply it in real. The main purpose of this research is to develop optimum compressive strength of corrugated fiber board box which would be used to American export packaging of fresh agricultural products such as perilla leaves, green red pepper and spinach.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.43.2-43.2
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• 2011

Wind turbine pitch/yaw bearings are relatively big and have different operating conditions like very heavy load to support compared with widely used industrial bearings. Once pitch/yaw bearings failed, according to their special surroundings, serious damages like higher repair costs and additional costs by stopped electricity generation are occur. Therefore, pitch/yaw bearings must be designed to have enough strength and fatigue life under actual operating conditions. In this study, with finite element analysis, it was investigated that stress distribution between rolling elements and raceway and comparatively analyzed using widely used guideline (NREL DG03). Design parameters of wind turbine pitch/yaw bearings are also analyzed, and it could be used as reference for the large bearing design field.

• 해양환경안전학회지
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• 제4권2호
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• pp.43-52
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• 1998

Generally, the navigational safety of a ship under various loading conditions is evaluated by a loading manual. However, the loading manual handles only statical factors such as weight and buoyancy of ship without including any wave conditions. Practically ship's safety is much concerned with the occurrences on the rough sea as propeller racing, rolling, deck wetness, vertical acceleration, lateral acceleration, slamming and so on. The purpose of this paper is to present a synthetic and practical evaluation method of navigational safety using the integrated seakeeping performance index(ISPI) under loading conditions of ship in seaways. The method is calculated by means of the ISPI by measuring only vertical acceleration. Judgement of dangerousness is carried out for four lading conditions : homogeneous full loaded, half loaded, heavy ballast loaded, and normal ballast loaded conditions. In developing the practical evaluation system of navigational safety, it is useful to solve the difficulties in measuring factors by sensors. And by applying the evaluation diagrames, navigators are able to avoid dangerousness by keeping away of the danger encountering angle of wave direction which the diagram shows.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(II)
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• pp.801-806
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• 2002

The operation of double deck train have increased in many countries such as Japan france, and the Netherlands as efficient, safe and convenient alternative transportation systems. Because of continuous concentration of population into Seoul metropolitan and serious traffic jam, the number of passengers using the commuter train have been increased rapidly. Considering these situations, we can find one of the solutions for heavy traffic problems through double deck trains. Stainless steel, and aluminum extruded panel are used to reduce the weight of double deck train. In this paper we compare the results of structural analysis of the double deck car body structures with Al extruded panels and stainless steel. We hope the results of this study may be used as basic guidelines in designing double deck trains in the future.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.66.1-66
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• 2001

As choosing proper length of boom of container crane according as sort of vessels(18, 22, 24 columns and so on), reinforcing of capacity of DC motor to transport heavy loads, it´s structure being oversized with flexibility and durability, the study is progressing on the automation for convenient operation and effective control. We often cannot but work slowly caused by swaying(pitching, rolling) of vessel. We can get productivity and efficiency by getting over it. The factors of swaying, as fellow; - wave caused by vessels around moving - wind and wave caused by weather change - vessel´s moving by change of load weight - tide - move of vessel According to ...

• Genomics & Informatics
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• 제10권4호
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• pp.249-255
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• 2012

In this study, fosmid cloning strategies were used to assess the microbial populations in water from the International Space Station (ISS) drinking water system (henceforth referred to as Prebiocide and Tank A water samples). The goals of this study were: to compare the sensitivity of the fosmid cloning strategy with that of traditional culture-based and 16S rRNA-based approaches and to detect the widest possible spectrum of microbial populations during the water purification process. Initially, microbes could not be cultivated, and conventional PCR failed to amplify 16S rDNA fragments from these low biomass samples. Therefore, randomly primed rolling-circle amplification was used to amplify any DNA that might be present in the samples, followed by size selection by using pulsed-field gel electrophoresis. The amplified high-molecular- weight DNA from both samples was cloned into fosmid vectors. Several hundred clones were randomly selected for sequencing, followed by Blastn/Blastx searches. Sequences encoding specific genes from Burkholderia, a species abundant in the soil and groundwater, were found in both samples. Bradyrhizobium and Mesorhizobium, which belong to rhizobia, a large community of nitrogen fixers often found in association with plant roots, were present in the Prebiocide samples. Ralstonia, which is prevalent in soils with a high heavy metal content, was detected in the Tank A samples. The detection of many unidentified sequences suggests the presence of potentially novel microbial fingerprints. The bacterial diversity detected in this pilot study using a fosmid vector approach was higher than that detected by conventional 16S rRNA gene sequencing.

• 공업화학
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• 제20권3호
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• pp.301-306
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• 2009

본 연구에서는 냉연도금공장의 각 단위공정에서 발생되는 폐수를 미생물을 이용하여 안정하게 처리하기 위하여 각 폐수의 특성파악과 처리조건을 도출하고자 하였다. 발생되는 폐수 중 알칼리성폐수가 전체폐수의 64%를 차지하였으며, 산중금속함유폐수는 30%를 차지했다. 탈류폐액의 COD는 53890 mg/L로 전체 폐수발생량의 0.03%에 불과함에도 불구하고 COD의 53%를 유발하고 있었으며, COD의 94%는 SCN에 의해 기인하였다. 혼합폐수를 미생물로 처리할 때 혼합폐수 중 SCN농도가 200 mg/L 이하일 때 제거가 용이하였다. 반면 COD 유발물질은 400 mg/L 이하가 되더라도 처리효율이 미흡하였다. 이는 탈류폐액 중에는 난분해성 유기물질이 다량 함유되어 있기 때문이라 판단된다. 혼합폐수를 처리할 때 초기에 pH가 7.33이었지만 8 h 후에는 7.99로 상승하였다. 이는 탈류폐액에 함유된 SCN이 박테리아에 의해 분해될 때 발생되는 암모니아에 의해 기인한 것으로 사료된다.

• 한국자동차공학회논문집
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• 제24권2호
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• pp.137-143
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• 2016

The fifth wheel coupler is a heavy automotive coupling structure which connects a tractor and a trailer used for heavy-duty trucks widely. It is subjected to various loads simultaneously such as rolling, pitching and yawing loads as well as coupling frictional and impact loadings. Most of existing couplers have been overdesigned and, therefore, it is necessary to reduce the dead weight to increase the fuel efficiency. The topology optimization was applied in order to find conceptual layout designs which could show major load paths and ribs locations, and then the size structural optimization was performed in order to determine the heights and thicknesses of coupler ribs with the predetermined various loading conditions for the development of a new slim coupler with a minimum weight and high enough strength and stiffness. As the results of the topology optimum design, an efficient new coupling structure for truck trailers was designed. The weight of the new fifth wheel coupler was reduced by 4.9 %, compared with the existing one, even though all strength requirements were satisfied. The fatigue test of the new coupler was performed with cyclic vertical loads (+78.4 to +235.2 kN) and horizontal loads (-91.2 to +91.2 kN) simultaneously at 1 Hz and the life of 2,000,000 cycles were achieved without failure.

• 한국가구학회지
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• 제21권4호
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• pp.273-283
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• 2010

Structural larger timber have some weak points as like much longer drying time at lower MC(15%), a considerable check developing and the difficulty for the chemicals injection, so it is necessary to develop lighter structural size member for using the new Hanok, heavy timber construction, living necessaries, furniture and industrial goods. The developed skin timber can be a good raw material for those uses. Skin timber is a hollowed timber which be bored out of its considerable cross-sectional area. The intention of this study was the evaluation of compressive capacity of skin timber. Specially, skin timbers which have more than 200mm in sizes were used to analyze the compressive capacity. From the results of this study, the following conclusions have been made: 1. Though considerable inner parts were bored out, both pine skin timber and larch skin timber showed a good compressive capacity to that of non-bored solid timber. 2. According to ASTM, pine skin timber showed various failure types, but Splitting type, Brooming and end rolling type were main failure types for the larch skin timber. 3. Pine skin timber didn't show the significance between cylindrical shape and rectangular shape, but larch skin timber showed the significance between two shapes. Therefore, for the larch skin timber, cylindrical shape and rectangular shape should be used as a column uses and beam uses respectively. 4. Pine skin timber and larch skin timber didn't show the significance on the compressive capacity. There is not much difference of compressive capacity between them, so it can be possible to select on the user convenience.