많은 승객이 이용하는 여객선 등, 선박의 사고 예방을 위해 안전과 관련된 규정이 매년 강화되고 선박에 적용하고 있지만 선 박에서의 사고는 감소하지 않고 있다. 선박에서의 화재 사고 시 화재 발생 위치에 따라 승객의 탈출 시간이 변화하고, 유해 요인에 의한 위험성이 증가할 수 있다. 화재 위치 변화에 따른 유해 요인들의 위험성과 탈출 시간지연의 원인을 파악하고, 시간지연을 감소시키는 방 안을 모색하기 위한 연구를 진행하였다. 선박 승객 거주 구역 화재 시 연소생성물의 유동과 승객의 탈출 과정을 확인하기 위해 FDS를 기반으로 하는 Pyrosim과 Pathfinder를 이용하여 화재 및 승객 피난 시뮬레이션을 진행하였다. 화재 발생 위치 변화에 따라 탈출로의 가시 거리 평균값은 3.1m에서 4.2m로 탈출 과정에서 안전하지 않고, 승객의 탈출 시간은 화재가 발생하지 않은 경우보다 9초에서 34초가 늘어 나는 것을 확인하였다. 안전성 향상 방안인 제연설비를 임의로 적용하여 동일 시뮬레이션 진행하였다. 화재 구역의 평균 가시거리는 14.9m에서 22.0m까지 증가하여 개선되는 것을 확인할 수 있다. 제연설비 설치 여부에 따라 0.8초에서 8.3초의 탈출 시간이 개선되었다. 해당 구역의 안전성 향상 방안을 적용한 결과, 적정한 제연설비가 작동된 이후로 연소생성물에 의한 승객의 위험성이 감소함을 확인할 수 있다.
국내에서 제조되어 유통되는 식물성 대체육을 대상으로 일반성분(수분, 단백질, 지방), 지방의 산패도, 지방산의 조 성, 아플라톡신, 중금속 함량을 분석하였다. 그 결과 한번 익힌 후 건조된 형태의 식물성 대체육보다 익히지 않고 수분이나 지방에 의해 성형과정을 거친 냉동제품에서 상 대적으로 많은 양의 지방을 함유하고 있음을 확인할 수 있었다. 조지방 함량이 1 g을 넘는 시료를 대상으로 지방 의 산패도(산가, 과산화물가)를 측정했다. 그 결과 일부 시 료에서 높은 산가 및 과산화물가가 측정되었으나 식품공 전상에 대체육에 대한 정확한 분류가 되어있지 않아 산패 도에 대한 안전성을 판단하기 위한 규격이 필요해 보인다. 가스크로마토그래피를 사용하여 지방산 조성을 분석한 결 과 대부분은 불포화지방산이 차지하고 있지만, 일부 포화 지방산의 함량이 높은 시료가 있었다. 포화지방산 및 불 포화지방산의 함량이 높은 식물성 대체육을 식물성 유지 를 사용하여 가열조리를 거쳐 섭취하게 된다면, 많은 양 의 지방을 섭취하게 될 수 있음을 예측할 수 있다. 또 가 스크로마토그래피를 사용한 지방산 분석법을 통해 식물성 대체육에 동물 유래 지질이 함유되어있지 않음을 확인할 수 있었다. 이는 이후에 식물성 대체육에 대한 영양표시 성분 및 실제성분의 대조 시에 활용될 수 있음을 시사한 다. 식물성 대체육에 대하여 아플라톡신을 분석한 결과 현 재 식품공전에 제시된 농산물 중 아플라톡신 기준규격에 대하여 적합인 수준이나 미량 검출되는 것을 확인하였다. 중금속의 분석 결과 모두 불검출이었으나 환경요인 및 원 재료에 따라 중금속의 오염이 의심될 시에 중금속 분석을 진행할 수 있을 것으로 판단된다. 이러한 실험결과를 통 해 국내에 유통되고 있는 일부 식물성 대체육에 대한 안 전성을 확인하였으나 산가, 과산화물가, 아플라톡신, 중금 속은 대체육에 대하여 구체적인 분류 및 적합 규격이 마 련되어 있지 않아 적합 판정시에 비슷한 성향을 가진 식 품군에 대조하여 판단해야 하는 어려움이 있었다. 따라서 기존의 기준에 대하여 검토 또는 변경을 거쳐 식물성대체 육에 대한 관리기준이 설정한다면 유사한 식품군의 건전 성 및 적합성을 유지하는 것에 도움이 될 것으로 판단된다.
The critical hazards generated from operation of a melting facility for metal radioactive waste are mainly assumed to be such as vapor explosion, ladle breakthrough and failure in the hot-cell or furnace chamber using remote equipment. In case of vapor explosion, material containing moisture and/or enclosed spaces may, due to rapid expansion of gases when heated, cause an explosion and/or violent boiling. The rapid expansion of gases may lead to ejection of molten radioactive metal from the furnace into the furnace hall. If there is a large amount of liquid the explosion may damage or destroy technical barriers such as facility walls. The consequences for the facility ranges from relatively mild to very severe depending on the force of the explosion as well as the type of waste being melted. Nonradiological consequences may be physical damage or destruction of equipment and facility barriers, such as walls. Due to the radiological consequences a longer operational shutdown would likely be required. Cleanup efforts would include cutting of solidified metal in a problematic radiological environment requiring use of remote technology before damage and repair requirements can be assessed. Even though there is a risk for direct physical harm to operators for example in the control room and hot-cell, this analysis focuses mainly on the radiological impact. The extent to which remote equipment could be used in the decontamination effort will largely determine the health consequences to the workers. It is reasonable to assume that there will be a need for workers to participate manually in the effort. Due to the potentially large dose rates and the physical environment, it is possible that the maximum allowable dose burden to a worker will be reached. No major consequence for the environment is expected as most of the radioactivity is bound to the material. In case of ladle breakthrough, a ladle breakthrough involves loss of containment of the melt due to damage of the ladle. This may be caused e.g. by increased wear due to overheating in the melt, or from physical factors such as mechanical stress and impact from the waste. A ladle breakthrough may lead to spread of molten metal in the furnace hall. Molten metal coming into contact with the surrounding cooling equipment may cause a steam explosion. The consequences of a ladle breakthrough will depend on the event sequence. The most severe is when the molten metal comes into contact with the cooling system causing a vapor explosion. The basic consequences are assumed to be similar to those of the vapor explosion above. While the ejection of molten metal is likely more local in the ladle breakthrough scenario, the consequences are judged to be similar. In case of failure in the hot-cell or furnace chamber using remote equipment, the loss of electric supply or technical failure in the furnace causes loss of power supply. If not remedied quickly, this could lead to that the melt solidifies. A melt that is solidified due to cooling after loss of power cannot be removed nor re-melted. This may occur especially fast if there is not melted material in the furnace. An unscheduled replacement of the refractory in the furnace would be required. It could be unknown to what degree remote equipment can be used to cut a solidified melt. It is therefore assumed that personnel may need to be employed. This event could not have any impact on environment
Working with molten metal has always been and will always be a dangerous workplace. No matter how carefully equipment is designed, workers are trained and procedures are followed, the possibility of an accident can occur in melting workplace. Some primary causes of melt splash and furnace eruptions include wet or damp charge material, dropping heavy charge into a molten bath, wet or damp tools or additives and sealed scrap or centrifugally cast scrap rolls. Induction melting brings together three things (water, molted metal and electricity) that have the potential for concern if the furnace is not properly working. Induction furnace must have a water cooling system built into the coil itself. Water picks up the heat caused by the current as well as heat conducted from the metal through the refractory. The water carries the heat to a heat exchange for removal. Spill pits serve to contain any molten metal spilled as a result of accident, run out or dumping of the furnace in an emergency. If a leak is suspected at any time, cease operation and clear the melt deck area of all personnel and empty the furnace. Molten metal fins can penetrate worn or damaged refractory and come into contact with the coil. A furnace or a close capture hood which suddenly swings down from a tilted position will cause injury or death. Whenever workers are working on a furnace or close capture hood when it is in the tilted position, be sure that it is supported with a structural brace that is strong enough to keep it from dropping if hydraulic pressure is lost. In theory refractory wear should be uniform, however, in practice this never occurs. The most causes of lining failure are improper installation of refractory material, inadequate sintering of refractory material, failure to monitor and record normal lining wear, allowing the lining to become too thin, installation of the wrong refractory, improper preheating of a used cold lining, failure to properly maintain the furnace the sudden or cumulative effects of physical shocks or mechanical stress, and excessive slag or dross buildup. Pouring cradles provide bottom support for crucibles. A crack in the crucible occur below the bottom ring support, the bottom of the crucible can drop and molten metal will spill and splash, possibly causing serious injury or death. To reduce this danger, a pouring cradle that provides bottom support for the crucible must be used. Power supply units must have safety locks and interlocks on all doors and access panels. Workers who work with low voltage devices must be made aware of the risk posed by high levels of voltage and current. The most causes of accidents are introduction of wet or damp material, improper attention to charging, failure to stand behind safety lines, coming into contact with electrically charged components and lack of operator skills and training. Only trained and qualified personnel are to have access to high risk areas. Safety lockout systems are another effective measure to prevent electrical shock
세계적으로 버섯에 대한 소비는 매년 증가하고 있으며 한국에서는 느타리버섯, 양송이버섯, 팽이버섯이 주로 유 통되고 있다. 하지만, 버섯의 재배와 가공 과정에서 미생 물 오염을 예방하기 위한 대안의 부재로 인하여 Listeria monocytogenes와 같은 병원성 미생물의 오염이 검출되고 있으며 버섯에 의한 식중독 및 리콜 사례가 다수 보고되 고 있다. 버섯에서 오염된 미생물을 저감화하는 방법으로 는 화학적 및 물리적 처리, 또는 이들을 결합하여 사용하는 병용처리 방법이 이용되고 있다. 화학적 처리로는 염소 혼 합물, 과산화아세트산, 4차 암모늄이온 화합물이 주로 사용 되고 있으며 오존과 전해수를 이용한 방법도 최근에 개발 되었다. 물리적 처리로는 초음파, 방사선조사, 콜드 플라즈 마 기술이 이용되고 있으며, 병용처리 방법으로는 자외선/ 염소 혼합물, 오존/유기산, 초음파/유기산 등이 연구되었다. 본 리뷰에서는 국내에서 소비되는 버섯의 종류와 그에 대한 미생물 오염도를 조사하고, 버섯에 오염된 미생물을 제 어할 수 있는 기술에 대하여 조사하여, 정리하였다.
We attempted to provide an overview of the laws and current state of the 3D printing industry in South Korea and around the world, using the annual industry surveys and the Wohler report. Additionally, we reviewed articles relating to the potential exposure to hazards associated with 3D printing using metal materials. In South Korea, there were 406 3D printing-related businesses, employing 2,365 workers, and the market size was estimated at 455.9 billion won in 2021. Globally, the average growth rate of the 3D printing industry market over the past 10 years was 27.4%, and the market size was estimated at $11.8 billion in 2019. The United States had the highest cumulative installation ratio of industrial 3D printers, followed by China, Japan, Germany, and South Korea. A total of 6,168 patents related to 3D printing were registered in the US between 2010 and 2019. Harmful factors during metal 3D printing was mainly evaluated in the powder bed fusion and direct energy deposition printing types, and there is a case of material extrusion type with metal additive filaments. The number, mass, size distribution, and chemical composition of particles were mainly evaluated. Particle concentration increases during the opening of the chamber or post-processing. However, operating the 3D printer in a ventilated chamber can reduce particle concentration to the background level. In order to have a safe and healthy environment for 3D printing, it is necessary to accumulate and apply knowledge through various studies.
연구에서는 한국 시민들의 지진 재해 준비도를 알아보기 위해 지진에 대한 지식, 인지, 대처의 3개 구인으로 구성된 설문 문항을 개발하고 비례 층화 표본 추출 방법으로 수집된 1,256명 시민의 응답을 라쉬분석, 추리통계, 군집 분석 기법을 이용하여 분석하였다. 연구 결과는 다음과 같다: 첫째, 시민들의 지진 재해 준비도 분석 결과, 전체적으로 시민들의 지진 재해 준비도는 ‘보통’ 수준이었으며, 지식과 인지에 비해 대처가 상대적으로 낮은 것으로 나타났다. 둘째, 지진 재해 준비도와 관련된 변인 분석 결과, 지진 재해 준비도에 영향을 주는 변인으로는 성별, 교육 수준, 실제 거리, 안전 인식이 있었다. 셋째, 지진 재해 준비도의 3개 구인 간 상관관계를 분석한 결과, 지식, 인지, 대처 세 가지 구인은 높은 상관을 나타내 구조적으로 서로 밀접한 관계를 보였다. 또한, 성별과 교육 수준이 달라도 이러한 구조적 상관은 비슷하게 나타났다. 군집 분석 결과, 5개 유형의 집단으로 구분되었으며 지진 재해 준비도 3개 구인의 수준이 중간 정 도로 서로 비슷한 집단 유형이 대부분을 차지하였다. 이 연구 결과를 토대로 시민들의 지진 재해 준비도 함양을 위한 교육의 지향점을 제안하였다.
This study aimed at elementary, middle, and high school dietitians who purchase ingredients for school meals. Therefore, for the study, the awareness and usage of nutritional information by 108 teachers and dieticians on 5 hazard-free meals using multivariate analysis of variance were investigated during May 18~21, 2021. Among the five questions that asked the general perceptions of school meal dietitians of 5 hazard-free meals, the perception that the “5 hazard-free foods can be easily distinguished” was the lowest. Problems were associated with using the 5 hazard-free meals such as “expensive price,” “no variety in items,” “disruption in the supply and demand,” “inconsistent quality,” and “lack of taste,” in that order. Therefore, to improve 5 hazard-free school meal service, it is necessary to not only lower the price burden by providing subsidies to schools but also improve the development and distribution structure of various 5 hazard-free foods.
The Ministry of Science, ICT and Future Planning made law for Pre-Hazard Risk Analysis in December 31, 2014 to protect researchers from continuing accidents in laboratory. Conducted before an experiment, Pre-Hazard Risk Analysis finds hazards of the experiment and rules to manage the hazards.So the Pre-Hazard Risk Analysis can support laboratory safety system by prevent accidents in laboratory. Pre-Hazards Risk Analysis is newly created system so that executors need Guidelines to perform this analysis properly. This study is to develop guide tool for Pre-Hazard Risk Analysis by analyzing other risk assessment systems; PSM, Off-site Consequence Assessment, laboratory safety system. Also, this study suggested how to establish database for Pre-Hazard Risk Assessment by analyse KRAS.
Main cause of accidents is just not always bad luck. Literature on safety has emphasised on the facts that accident finally leads to unfortunate consequence. The first step of risk assessment is to identify the hazards that are present. The Routine Ship Towage, also called harbour towage, is potentially a hazardous operation. The main objective of this research is to identify and quantify the important factors impacting on the safety of routine ship towage operations in Indian coast. In doing so, initially, the existing literature on factors influencing safety of harbour towage operation was analysed to design questionnaire. Rest necessary data was collected through questionnaires. Finally, the factor analysis (Principal Component analysis) was applied to find grouped dimensions from identified hazard variables from literature and subsequently the critical analysis of incident type frequency, cause and consequences to get a clear picture of critical safety risk factors. As a result, the research found 20 criteria in 6 dimensions safety risk factors such as Crew Incompetency, Rough Weather, Poor Work Process, Suitability of Tug Type, Poor Safety Management System, and Poor Navigational Risk Assessment.
Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.