• Steel and Composite Structures
• /
• 제37권5호
• /
• pp.589-603
• /
• 2020

This paper presents an investigation of the thermal performance of composite floor slabs with profiled steel decking exposed to fire effects from floor. A detailed finite-element model has been developed by representing the concrete slab with steel decking under of it and steel beam both steel parts protected by intumescent coating. Although this type of floor systems offers a better fire resistance, passive fire protection materials should be applied when a higher fire resistance is desired. Moreover, fire exposed side is so crucial for composite slab systems as the total fire behaviour of the floor system changes dramatically. When the fire attack from steel parts, the temperature rises rapidly resulting in a sudden decrease on the strength of the beam and decking. Herein this paper, the fire attack side is assumed from the face of the concrete floor (top of the concrete assembly). Therefore, the heat is transferred through concrete to the steel decking and reaching finally to the steel beam both protected by intumescent coating. In this work, the numerical model has been established to predict the heat transfer performance including material properties such as thermal conductivity, specific heat and dry film thickness of intumescent coating. The developed numerical model has been divided into different layers to understand the sensitivity of steel temperature to the number of layers of intumescent coating. Results show that the protected composite floors offer a higher fire resistance as the temperature of the steel section remains below 60℃ even after 60-minute Standard (ISO) fire and Fast fire exposure. Obtaining lower temperatures in steel due to the great fire performance of the concrete itself results in lesser reductions of strength and stiffness hence, lesser deflections.

• Molecules and Cells
• /
• 제23권2호
• /
• pp.228-238
• /
• 2007

Since molecular structure of hnRNP is not available in foreseeable future, it is best to construct a working model for hnRNP structure. A geometric problem, assembly of $700{\pm}20$ nucleotides with 48 proteins, is visualized by a frame work in which all the proteins participate in primary binding, followed by secondary, tertiary and quaternary binding with neighboring proteins without additional import. Thus, 40S hnRNP contains crown-like secondary structure (48 stemloops) and appearance of 6 petal (octamers) rose-like architectures. The proteins are wrapped by RNA. Co-transcriptional folding for RNP fibril of FMR1 gene can produce 2,571 stem-loops with frequency of 1 stem-loop/15.3 nucleotides and 53 40S hnRNP beaded structure. By spliceosome driven reactions, there occurs removal of 16 separate lariated RNPs, joining 17 separate beaded exonic structures and anchoring EJC on each exon junction. Skipping exon 12 has 5'GU, 3'AG and very compact folding pattern with frequency of 1 stem-loop per 12 nucleotides in short exon length (63 nucleotides). 5' end of exon 12 contains SS (Splicing Silencer) element of UAGGU. In exons 10, 15 and 17 where both regular and alternative splice sites exist, SS (hnRNP A1 binding site) is observed at the regular splicing site. End products are mature FMR-1 mRNP, 4 species of Pri-microRNAs derived from introns 7,9,15 and 3'UTR of exon17, respectively. There may also be some other regulatory RNAs containing ALU/Line elements as well.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.75-75
• /
• 2011

Recently, dye-sensitized solar cell (DSSC) attracts great attention as a promising alternative to conventional silicon solar cells. One of the key components for the DSSC would be the nanocrystalline TiO2 electrode, and the control of interface between TiO2 and TCO is a highly important issue in improving the photovoltaic conversion efficiency. In this work, we applied various interfacial layers, and analyzed their effect in enhancing photovoltaic properties. In overall, introduction of interfacial layers increased both the Voc and Jsc, since the back-reaction of electrons from TCO to electrolyte could be blocked. First, several metal oxides with different band gaps and positions were employed as interfacial layer. SnO2, TiO2, and ZrO2 nanoparticles in the size of 3-5 nm have been synthesized. Among them, the interfacial layer of SnO2, which has lower flat-band potential than that of TiO2, exhibited the best performance in increasing the photovoltaic efficiency of DSSC. Second, long-range ordered cubic mesoporous TiO2 films, prepared by using triblock copolymer-templated sol-gel method via evaporation-induced self-assembly (EISA) process, were utilized as an interfacial layer. Mesoporous TiO2 films seem to be one of the best interfacial layers, due to their additional effect, improving the adhesion to TCO and showing an anti-reflective effect. Third, we handled the issues related to the optimum thickness of interfacial layers. It was also found that in fabricating DSSC at low temperature, the role of interfacial layer turned out to be a lot more important. The self-assembled interfacial layer fabricated at room temperature leads to the efficient transport of photo-injected electrons from TiO2 to TCO, as well as blocking the back-reaction from TCO to I3-. As a result, fill factor (FF) was remarkably increased, as well as increase in Voc and Jsc.

• 한국건설관리학회:학술대회논문집
• /
• 한국건설관리학회 2001년도 학술대회지
• /
• pp.410-415
• /
• 2001

Earned Value Management System(EVMS)은 최근 건설 프로젝트를 관리하는데 매우 유용한 도구로 인식되고 있으며, 정부차원에서 적극적으로 도입을 검토하고 있는 선진 관리기법이다. 이 EVMS는 미국방성에 의해 1960년대부터 프로젝트의 효율적인 관리를 위해 개발된 C/SCSC에 기반을 두고 있으며, 국내외에서 정부발주공사뿐만 아니라 민간발주의 건설프로젝트를 관리하는 도구로 활용하기 위해 연구가 활발하게 진행되고 있다. 본 연구에서는 공정관리 프로그램과 복합작업모델(Workpackaging model)을 바탕으로 건설프로젝트의 EV계획과 분석이 효과적으로 이루어질 수 있도록, 제조업의 재고관리모형중의 한 형태로 조립제품의 자원운영계획을 수립하는데 우수한 기법으로 알려진 MRP기법을 활용하여 EVMS가 건설현장에서 보다 용이하고, 효과적으로 활용될 수 있는 방안을 제시하고자 한다.

• 한국건설관리학회논문집
• /
• 제13권1호
• /
• pp.53-66
• /
• 2012

갱폼은 기존 목재 및 철재 거푸집과 비교하여 매 사용 시 작은 부재의 조립/해체를 반복하지 않고 대형화, 단순화를 통해 한 번에 설치하고 해체할 수 있는 시스템화 된 거푸집이다. 그러나 ACS(Auto Climbing System)와 같은 첨단 거푸집에 비해 경제성을 제외한 다른 측면(생산성, 안전성, 품질 등)에 있어서는 1) 타워크레인 양중부하 증가, 2) 갱폼 인양 중 안전사고 증가, 3) 갱폼 박리 작업 생산성 저하, 4) 기후 영향으로 인한 작업 중지, 5) 생산성, 노무비, 품질 저하 등의 문제점을 지니고 있는 것으로 조사되었다. 따라서 본 연구에서는 타워크레인의 부하를 감소시킴과 동시에 인양 속도를 향상시킴으로써, 작업 생산성 향상 및 노무자 안전성 확보, 콘크리트 구조체의 품질 등을 향상시켜 공동주택 건설 현장에서 범용적으로 사용가능한 공동주택 전용 갱폼 인양 자동화 장비의 개념 모델을 제시하고자 한다. 이를 위해 본 연구에서는 기존 문헌 분석 및 건설 현장관리자와의 설문조사를 수행하여 공동주택 전용 갱폼 인양 자동화 기술 개발 시 요구되는 고려요소 도출 및 효용성 분석 등을 통해 '공동주택 전용 갱폼 인양 자동화 장비의 개념 모델'을 제시하였다.

• 한국산업정보학회:학술대회논문집
• /
• 한국산업정보학회 2006년도 춘계 국제학술대회 논문집
• /
• pp.211-217
• /
• 2006

반복학습제어는 특정목적 궤도의 반복작업을 수행하는 정밀도를 개선하는 제어기를 개발하는 기술이다. 기존 연구에서는 수직다물체의 반복정밀도를 개선하기 위하여 누적학습제어와 적응제어 기법을 한 반복영역에서 동시에 실시하는 기법을 개발하였다. 당초 이 기술은 생산조립라인의 산업용 로봇에서 발생하는 반복정밀도를 개선하기 위해 개발하였으며, 특히, 분산학습기법은 산업용 로봇에서 발생하는 실질적 제어 방식에 유효한 기법이다. 본 논문에서 개발한 제어기술은 한 반복영역의 모든 시간대의 입출력 정보를 동시에 학습하기 보다는 매 시간대의 입출력 정보를 각 시간대 마다 충분히 학습하고 다음 시간대의 정보를 학습하는 것이다. 본 논문에서 개발한 기술을 산업용 로봇과 의료기기에 적용하면 수직다물체의 정밀도 품질보증 확보에 큰 기여를 하게 된다.

• 한국마이크로전자및패키징학회:학술대회논문집
• /
• 한국마이크로전자및패키징학회 2001년도 Proceedings of 6th International Joint Symposium on Microeletronics and Packaging
• /
• pp.45-47
• /
• 2001

Due to pressure from threatened legislation in Europe, consumer and governmental pressure in Japan, and glob머 market considerations in the US, there is a rapidly growing interest in lead-free solderinger, Although the move to lead free soldering seems inevitable, many problems will arise in production assembly. It is generally acknowledged that the lead-free solders available offer a much s smaller process window than lead/tin, related mainly to the higher soldering temperatures which naturally result from increases of liquidus temperatures of at least 300 C. However, raising reflow temperatures from the current 220-2300 C to 250 2600 C will lead to problems with the boards and components as well as i increasing oxidation effects. There is a need to keep reflow temperatures low without reducing solderablity. Some results on benefits of inert atmospheres are discussed in this paper. For example, testing in a nitrogen atmosphere, with 300 ppm oxygen, by the N National Physical Laboratory (NPU has revealed clear benefits for ine$\pi$mg lead-free alloys, by restoring the solderability to lead/tin levels, by enabling lower soldering temperatures. However, there has been little testing over a range of oxygen levels in nitrogen and this is an important issue in determining n nitrogen supply and oven costs. Some results are reported here from work by NPL conducted for BOC in w which solderability was evaluated for tin기ead and tin/silver/copper eutectic a alloys in a wetting balance over a range of oxygen levels form 10 ppm to 21% ( (air). The studies confirm that acceptable wetting times occur in inert atmospheres a at soldering temperatures 20 to 300 C lower than are possible in air.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.305-309
• /
• 2007

FTL(Fuel Test Loop) is a facility that confirms performance of nuclear fuel at a similar irradiation condition with that of nuclear power plant. FTL construction work began on August, 2006 and ended on March, 2007. During Construction, ensuring the worker's safety was the top priority and installation of the FTL without hampering the integrity of the HANARO was the next one. The installation works were done successfully overcoming the difficulties such as on the limited space, on the radiation hazard inside the reactor pool, and finally on the shortening of the shut down period of the HANARO. The Commissioning of the FTL is to check the function and the performance of the equipment and the overall system as well. The FTL shall start operation with high burn up test fuels in early 2008 if the commissioning and licensing progress on schedule.

• 대한조선학회논문집
• /
• 제50권4호
• /
• pp.262-271
• /
• 2013

Owing to the development of mobile communication technology during the last a few years, the number of users of mobile devices such as the smartphone and the tablet PC has increased rapidly. As a result, the range of applications of the mobile devices has also been greatly expanded from an application for the convenience of daily life to an application for assisting the operations of industrial fields. Especially, portability of mobile devices can provide great help in collecting and using information on the production site. In shipbuilding production processes, it is difficult to collect changes of circumstance in the field and reflect the changes to schedule due to the low production automation rate and frequent changes in schedule. In this study, we propose a system to solve the problems of shipbuilding production processes such as the ones described above by using mobile devices. First of all, we organize the production information and production processes of the panel line through the analysis of shipyard panel line operations. Next, we have developed a system that can support the production execution plan of the panel line and monitor the production processes in the field. The system was developed utilizing application virtualization to allow access to the system from various platforms of mobile devices and PC's. The system was implemented using ooCBD methodology considering the future expansion of the system and ease of maintenance.

• 한국해양공학회지
• /
• 제26권5호
• /
• pp.63-72
• /
• 2012

The product lifecycle of a marine vessel can be classified into the design-production, operation-maintenance, and disposal phases. During the operation and maintenance phase, status data should be gathered from the major machinery and instruments installed on the marine vessel in order to perform efficient maintenance work. Although a PLM (product lifecycle management) system can manage the product information during the design and assembly stage, a PLM based on asset management technology is more appropriate for product information management during the operation stage. Product embedded information devices (PEIDs) are suggested for gathering real-time maintenance information during the operation and maintenance lifecycle. A PEID allows PLM to provide the capability of offering active information exchange between the lifecycle management system and equipment. This study designed a PEID to effectively obtain information and interact with a PLM system. It consists of sensors, wireless communication, and a micro-processor, which allow it to accumulate status data on the PLM system. The embedded information device and PLM enable the seamless information flow, tracking, and updating of MRO (maintenance repair and overhaul) information for a product throughout the middle of the product lifecycle.