• 대한기계학회논문집A
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• 제26권4호
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• pp.787-793
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• 2002

In this study, a bar impact test of low velocity was carried out to gain an insight into the damage mechanism and sequence induced in alumina plates(AD 85 and AD 90) under impact conditions. An experimental setup utilizing an instrumented long bar impact was devised, that can measure directly the impact force applied to the specimen and supply a compressive contact pressure to the specimen. During the bar impact testing, the influences of the contact pressure applied along the impact direction to the specimen on the fracture behavior were investigated. The measured impact force profiles explained well the damage behavior induced in alumina plates. The higher contact pressure to the specimen led to the less damage due to the suppression of radial cracks due to the increase in the apparent flexural stiffness of plate. It had produced the change of damage pattern developed in the specimen; from the radial cracks to the local contact stress dominant damage. It would contribute to the improvement of the ballistic property in ceramic plates. The observed results showed the following sequence in damage developed: The development of cone crack at impact region, the formation of radial cracks from the rear surface of plate depending on the plate thickness, the occurrence of crushing within the cone envelope and the fragmentation.

• 한국건설관리학회논문집
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• 제20권2호
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• pp.44-52
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• 2019

기후변화로 인해 극한 기후 사상이 야기하는 피해의 빈도와 세기가 증가하고 있다. 사회기반시설물이 기후변화로 인한 위험에 대비되어 있지 않으면 시설물 자체와 그 주변 지역의 자산 손실이 발생할 수 있다. 따라서 기존의 기후에 근거하여 설계된 사회기반시설물들에 기후변화 적응기술을 도입하여 미래에 발생할 손실을 낮추어야 한다. 정책 결정자는 적응기술을 도입하기 위해 각 기술의 경제적 파급효과를 이해해야 한다. 기후변화 적응의 경제적 파급효과를 올바르게 이해하려면, 시설물에 직접적인 피해인 1차 피해와 기후 사상으로 인해 주변지역에 미치는 피해인 2차 피해를 모두 파악하여야 한다. 본 논문은 기후변화 적응기술들이 저감하는 1차 및 2차 피해액을 도출하기 위한 방법론을 제시하여, 각 사회기반시설물에 특화된 기후변화 적응기술 가치평가 방법을 제안하였다.

• 한국환경복원기술학회지
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• 제23권6호
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• pp.15-28
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• 2020

Urbanization and industrialization have caused increasing damage to national lands, and ecological restoration has proceeded without any specific assessment of this damage. The purpose of this study is to select indices to assess damaged areas through literature review and panel discussions, and to derive the importance of damaged area assessment indices by analyzing them through the Analytic Hierarchy Process (AHP). This study has derived, via literature review, six types of damage and a total of 18 related assessment indices. A total of 51 responses were collected from surveys and given to experts, and an AHP analysis conducted. As a result of the analysis, "Landform change (0.268)" was of the highest importance, with associated damage types as follows: "Soil contamination (0.193)", "Vegetation damaged (0.149)", "Surface soil loss (0.143)", "Change in soil physiochemical property (0.125)", and "Vegetation decline (0.122)". The analysis determined that the item of the highest importance in the overall assessment of damage was "Slope occurred area (0.100)", and that "Conductivity (0.022)" was of the lowest importance. This study can be presented as a criterion in determining the type and degree of damage in setting priorities for future ecological restoration projects.

• 대한공간정보학회지
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• 제24권1호
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• pp.43-50
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• 2016

우리나라의 도시화율은 점점 높아지고 있으며 이에 따라 도시인구 증가와 더불어 다양한 도시시설물들이 급속도로 도시에 집중되고 있는 실정이다. 이에 따라 다양한 재해로 인한 피해가 발생되고 있고 사회재난 중 화재는 교통사고와 더불어 도시에서 가장 많은 피해를 입히고 있다. 2015년 우리나라의 화재발생은 44,432건이 발생하여 253명의 사망자와 4,300억원의 재산피해가 발생하여 다양한 피해 저감 노력에도 불구하고 감소되는 추세를 보이고 있지 않다. 이에 본 연구에서는 국가화재정보시스템과 진주소방서를 통하여 2007년부터 2014년까지 발생한 진주시 화재자료를 수집하였으며 행정자치부의 시설물 현황 DB를 통해 진주시의 화재와 시설물의 군집성을 분석하고 화재위험도를 산출하였다. 그 결과 미국소방기술사회(SEPE:Society of Fire Protection Engineers) 기준에 따른 화재발생빈도에 대한 위험 등급을 4단계로 구분한 경우 가장 높은 A등급으로 업무시설, 위락시설, 자동차시설이 분류되었으며, 그 다음으로 U등급은 단독주택, 공동주택, 교육시설, 판매시설, 숙박시설, 집합시설, 의료시설, 산업시설, 생활서비스시설, EU등급은 기타주택이고, 마지막으로 가장 낮은 BEU등급은 위험물제조시설로 나타났다. 또한 인명피해를 기준으로 한 경우 가장 위험도가 높은 시설물은 위험물제조시설이었고 재산피해를 기준으로 한 경우는 집합시설과 산업시설이 가장 위험도가 높게 나타났다. 이상과 같이 도시에서 발생된 화재를 시설물별로 구분하여 발생빈도, 인명피해, 재산피해에 대해 위험등급을 산정하여 제시함으로서 도시공간에 분포한 시설물에 대한 화재저감대책을 수립하는데 효과적으로 활용할 수 있을 것으로 판단된다.

• 기술사
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• 제41권4호
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• pp.43-46
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• 2008

The extreme weather events have increased around the world this century. One of the main reasons of frequent occurrence is the change of atmospheric circulation by El nino. also Korea Peninsular is not exception. The 97 % of death toll and 89 % of property loss of total are related with extreme-weather events for the last 10 years. for example the heavy rainfall (1998-4999) and Typhoon Rusa and Mamie. In spite of the percent of death toll by extreme-weather disaster is increasing and the total population is growing. but the number of death toll from natural disasters is decreasing. It shows that the loss of property and life can be minimize by preparing the proper disaster prevention measures. There are several preparations to reduce the damage by extreme-weather events: Public facilities have overall check up, to recognize the weather alert, the awareness of the escape route and the art of measures

• 한국가구학회지
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• 제18권4호
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• pp.275-281
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• 2007

This study was carried out to know bending process property of bentwood by treatment methods such as microwave and ammonia solution treatment. Bentwood processing was operated on bending-jig form with 60mm and 100mm radius of curvature (ROC). The species was used to Korean red pine (Pinus densiflora). No significant difference was shown in bentwood processing method on ROC. In treatment method, ammonia solution treatment for bentwood was better in dimensional stability and working ability than that of microwave treatment. However, bentwood stress was reduced with ammonia solution treatment. Color of bentwood surface appearance has a dark tendency in ammonia solution treatment. But it seems to beautiful effect of apparent annual ring is rising esthetically by ammonia solution treatment. To utilize wood as a exterior material for living amenity, it has to be closely examined from various angles including surface property, degree of swelling and shrinkage, drying state, retaining strength, durability, safety, and insect damage.

• 한국정밀공학회지
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• 제20권4호
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• pp.183-188
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• 2003

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, the effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the Head Disk Interface (HDI) using a particle injection system. It was round that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except fer the particles of specific size and property. As a means to remove the particles of specific sire. the concept of using a stepped taper at the leading edge of the slider is proposed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.946-949
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• 2002

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, The effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the head-disk interface using a particle injection system. It was found that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except for the particles of specific size and property. As a means to removed the particles of specific size, the concept of using a stepped taper at the leading edge of the slider is proposed.

• 전기학회논문지
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• 제58권2호
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• pp.242-247
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• 2009

Forest Fire can cause a serious damage to overhead conductors. Therefore, the detailed investigation for the changes of mechanical and electrical properties of damaged conductors should be carried out to understand the effect of forest fires on conductors. This is very much important to maintain transmission line safely. Oxidation of overhead conductor was increased with temperature and time(maximum time : 30min). Conductivity of Al conductor was decreased by Agents. The detailed will be given in the text.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.54-55
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• 2013

Recently, The economic growth has increased carbon dioxide emissions. so, It is caused by social problem to environmental damage and human health due to global warming. Accordingly, The method solution is to the amount of cement and to use industrial by-product such as Blast furnace slag, Fly Ash, and Red-mud. Thus, The purpose of this study is to analyze the physical property of concrete with red-mud. So, this study carries out the basic performance test of concrete such as, air content, slump, and compressive strength. In this work test is conducted according to sequence of materials using concrete twin mixer.