• Journal of the Korean Institute of Gas
• /
• v.26 no.2
• /
• pp.39-48
• /
• 2022

The domestic gas detector installation standards applied to gas detectors, which are one of the facilities that can prevent accidents such as fire, explosion, and leakage that can cause serious industrial accidents, do not take into account the behavioral characteristics of hazardous chemicals in the atmosphere. It can be seen that the technical basis is insufficient because the standard is applied. Therefore, in this study, the size of the leak hole for each facility mainly used in chemical plants and the diffusion distance according to the concentration of interest of hazardous chemicals were analyzed, and based on this, the optimal installation distance for gas detectors for each material was suggested. Using the method presented in this study, more economical and effective gas detector installation can be expected, and furthermore, it can be expected to help prevent serious industrial accidents.

• Progress in Superconductivity and Cryogenics
• /
• v.10 no.1
• /
• pp.10-14
• /
• 2008

Differently from BSCCO tapes which are fabricated by powder-in-tube method, the coated conductors are made by the evaporation of YBCO on metal substrate. Due to this structural merit, although the coated conductors are generally used for large current transportation, they are expected to be favorable to the purpose of the fault current limitation as well. In this study, using YBCO coated conductor having copper stabilizer formed by plating technique(produced by Superpower Co.), we investigated the over-current characteristics of the coated conductor. The coated conductors had 85 A $I_c$ and 90 K $T_c$. The resistance of the conductor was 0.93 $m{\Omega}/cm$ at 300 K and 0.17 $m{\Omega}/cm$ at the temperature right above $T_c$. To the coated conductors, we applied the voltages of the range from 150 $V_{rms}$ to 230 $V_{rms}$ and measured the V-I curves using four probe method. From the results, we could analyze the electric behavior of the coated conductor in flux flow state. As the current exceed $I_c$, the currents were distributed into the superconductor and metal stabilizer. The amounts of the currents shared through both current paths were calculated under the assumption that the ,Joule heating was perfectly eliminated by $LN_2$ surrounding the conductor. Finally, the condition for the stable current flowing state which does not affect the conductor was established from the analysis on the over-current characteristics.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.2
• /
• pp.279-290
• /
• 2022

A superconducting fault current limiter(SFCL) is a power device that exploits superconducting transition to control currents and enhances the flexibility, stability and reliability of the power system within a few milliseconds. With a high phase transition speed, high critical current densities and little AC loss, high-temperature superconducting (HTS) wires are suitable for a resistive-type SFCL. However, HTS wires due to the lack of optimization research are rather inefficient to directly apply to a fault current limiter in terms of the design and capacity, for the existing method relied the characteristics. Therefore, in order to develop a suitable wire for an SFCL, it is necessary to enhance critical current uniformity, select optimal stabilizer materials and conducted research on the development of uniform stabilizer layering technology. The high temperature superconducting wires manufactured by this study get an average critical current of 804 A/12mm-width at the length of 710m; therefore, conducted research was able to secure economic performance by improving efficiency, reducing costs, and reducing size.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.479-479
• /
• 2021

최근 기상이변으로 인한 자연재해 발생이 증가하고 있고, 그에 따라 도시의 재난 대응력 강화가 국내에서는 물론 국제적으로도 중요한 이슈가 되고 있다. 특히 쇠퇴지역은 재난재해 발생 시 인적·물적 피해가 일반 지역 보다 상대적으로 크며, 복구에도 많은 시간과 예산이 소요되므로 대응책 마련을 위한 도시재생지역의 정밀한 재난재해의 위험성 분석 기술이 필요하다. 이에 본 연구에서는 도시재생사업 대상지(311개)에 대한 재난재해 유형별 위험성 및 회복성을 종합적으로 분석하는 종합진단 기법을 개발하고, 이를 적용한 프로토타입 시스템을 개발하였다. 재난재해의 범위는 「재난 및 안전관리 기본법」을 준용하여 이에 도시재생사업 시행에 영향을 받아 재난재해 발생에 따른 위험정도가 변화할 가능성이 높은 자연재해 (폭우, 폭염, 폭설, 강풍, 지진)5종과 사회재난 (화재, 붕괴, 폭발) 3종 총 8종으로 정의하였다. 종합진단 기법은 기후변화에 관한 정부간 협의체(IPCC) 위험도 평가 방법을 준용하여 위험요소 (위해성·취약성·노출성)와 대비·대응요소 (회복성)로 구분하고, 전문가 자문회의를 거쳐 재난재해에 특히 취약한 쇠퇴지역의 특성을 반영할 수 있는 종합진단지수 산정식을 개발하였다. 또한 쇠퇴지역 재난재해 종합진단 시스템은 도시재생 업무를 수행하는 사용자가 신속히 정보를 분석하고 활용에 용이하도록 Web-GIS 기반으로 설계하였으며, 종합진단 기법에 의해 산정된 분석결과를 100m × 100m 격자 단위의 등급으로 가시화한다. 분석 결과는 지속적인 연구 개발을 통해 최적의 도시재생사업 의사결정 지원 서비스를 위한 기초 분석 자료로 연계하여 활용되며, 분석 DB는 클라우드 서비스 기반의 도시재생 데이터 플랫폼을 통해 공유된다.

• Journal of the Institute of Convergence Signal Processing
• /
• v.24 no.2
• /
• pp.82-89
• /
• 2023

Due to the characteristics of ship structure, the compartment structure is complicated and narrow, so safety accidents frequently occur during the work process. The main causes of accidents include structural collisions, falling objects, toxic substance leaks, fires, explosions, asphyxiation, and more. Understanding the on-site conditions of workers during accidents is crucial for mitigating damages. In order to ensure safety, the on-site situation is monitored using CCTV in the ship, but it is difficult to prevent accidents with the existing method. To address this issue, a smart safety helmet equipped with location identification and voice/video communication capabilities is being developed as a safety technology. Additionally, the smart safety helmet incorporates environmental sensors for temperature, humidity, vibration, noise, tilt (gyro sensor), and gas detection within the work area. These sensors can notify workers wearing the smart safety helmet of hazardous situations. By utilizing the smart safety helmet and environmental sensors, the safety of workers aboard ships can be enhanced.

• Korean Journal of Culture and Social Issue
• /
• v.9 no.spc
• /
• pp.1-14
• /
• 2003

The purpose of this paper is to introduce eight articles which were written on the psychological mechanisms of accidents in Korean society and to suggest alternatives to prevent them. All of these articles were presented during the "Symposium of Safety" at the Annual Conference of the Korean Psychological Association, at Youngnam University through October 18~19, 2002. Frequently occurring accidents in Korean society are a very serious and enduring social issue. Psychological and cultural factors, as well as environmental factors, were found to be leading causes of the various accidents. The preventative alternatives for these accidents should be developed taking into account these factors. A nation-wide comprehensive institute for accident management is necessary to control accidents and to study and to develop preventive programs. The attitude of psychologists also needs to shift from the laboratory to the field toward accidents and from passive to aggressive toward issues facing Korean society.

• Journal of the Korea Concrete Institute
• /
• v.21 no.2
• /
• pp.179-186
• /
• 2009

The peculiarity pointed out for high strength concrete is the occurrence of spalling during a fire. Recently, there are many efforts such as development of all types of spalling reducing materials and other innovative materials in various fields. Need is now to examine the adequate mixing proportions of these materials. This study intended to derive experimentally and statistically mix proportions that can represent the basic quality requirements as well as the optimal effects on the fire-resistance for 4 types of functional materials that are metakaolin, waste tire chip, polypropylene fiber and steel fiber. Here, the tests were planned through an optimal test method using an orthogonal array table with 4 parameters and 3 levels. The statistical analysis adopted the response surface analysis method. Results verified mutual complementary contribution between the materials when using a combination of the functional materials selected as parameters for the strengthening of the fire-resistance of 80 MPa-class high strength concrete. Besides, the optimal conditions of the fire-resistance strengthening materials derived through response surface analysis were a volumetric replacement of silica fume by 80% of metakaolin, a volumetric replacement of fine aggregates by 3% of tire waste chip, and an addition of 0.2% of the whole volume by polypropylene fiber without mixing of steel fiber. In such cases, the basic characteristics as well as the fire-resistant characteristics of high strength concrete were also satisfied.

• Journal of the Korea Concrete Institute
• /
• v.18 no.1 s.91
• /
• pp.83-90
• /
• 2006

This paper investigates experimentally the fire resistance performance and spatting resistance of high performance reinforced concrete column member subjected to fire containing polypropylene fiber(PP fiber) and cellulose fiber(CL fiber). An increase in PP fiber and CL fiber contents, respectively resulted in a reduction of fluidity due to fiber ball effect. Air content is constant with m increase in fiber content. Compressive strength reached beyond 50 MPa. Based on fire resistance test, severe failure occurred with control concrete specimen, which caused exposure of reinforcing bar. No spall occurred with specimen containing PP fiber. This is due to the discharge of internal vapour pressure. Use of CL fiber superior to control concrete in the side of spatting resistance, localized failure at comer of specimen was observed. Corner of specimen had deeper neutralization than surface of specimen. Specimen containing PP fiber had the least damaged area due to spatting. Neutralization depth ranged between 6 and 8 mm Residual compressive strength of specimen containing PP fiber maintained 40%, which is larger than control concrete with 20% of residual strength. Specimen containing CL fiber had 25% or residual strength.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.9
• /
• pp.5861-5869
• /
• 2014

Existing studies of building exterior materials have focused on the colors or textures of cladding, and in terms of a design planning approach, have focused on the use of the environment and equipment and fire safety topics from an engineering perspective. As a result, little research has been done on performance guidelines for exterior materials, specifically according to the building type. Research into eco-friendly cladding materials is also in the rudimentary stage in a practical sense. In this study, the use of exterior materials over the last ten years in domestic construction was analyzed. The usage status of building exterior materials was evaluated quantitatively by frequency analysis, and its environmental performance is proposed through complex (qualitative + quantitative) analysis. The average value of the exterior material type number used for all analyzed buildings was 2.59. Glass, metal, stone, resin, cement, wood, and clay were used in that order with regard to the usage status. The analysis found that five of the materials satisfied the high efficiency and eco-friendly grading in terms of the four characteristics of an eco-friendly exterior. A list of eight eco-friendly elements was also proposed. The eco-friendly elements and characteristics of the exterior materials were derived to provide basic guidelines for domestic construction companies and design offices.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.3
• /
• pp.234-246
• /
• 2013

It was found that test piece heated rapidly by 3 kW microwave for 5 minutes satisfies the targeted temperature and the percentage of moisture content, and the highest rate of weight increase is obtained in case of 120 minute immersion in the mixture of phosphates and heterocyclic compounds, from the result of such analysis as: kiln drying schedule, flame retardent by flammability test, insect resistance by termites, and permeability of combined penetrant for the wood after assigning multifunctional finish by immersing conifer structural frame, which is used for the frame work of wooden house and indoor/outdoor finishing in flame retardant and insect repellent materials mixture with the remaining heat of microwave. In addition, after a test of flame retardent treated item, it was identified that every mixture of phosphates corresponds with the standards of flame retardent, and upon investigation of moritality of 7 days after putting termites, it was showed that test piece immersed in the mixture of phosphates and heterocyclic compounds has the best characteristics, showing over 96% of high moritality. From the analysis of inward permeability of combined penetrant for the wood, it was decided that excellent performance in the flame retardent and insect resistance of the wood revealed due to full penetration of combined penetrant as it was found that combined penetrant penetrated through the whole inner cells of the wood.