• 한국가스학회지
• /
• 제10권1호
• /
• pp.19-25
• /
• 2006

폭발한계는 가연성물질의 화재 및 폭발 위험성을 결정하기 위해 사용되는 중요한 연소 특성치 가운데 하나이다. 폭발한계는 상대 연소에 따라 가연성물질을 구분하는데 사용된다. 이런 구분은 가연성물질의 안전한 취급, 처리, 수송을 위해서 중요하다. 본 연구에서는 가연성혼합물의 구성하는 각 순수성분의 연소열과 기상 조성을 이용하여 폭발한계를 예측하였다. 제시된 방법론에 의한 계산값은 적은 오차범위에서 문헌값과 일치하였다. 따라서 제시된 결과로부터 가연성혼합물의 폭발특성치 예측 방법과 다른 가연성혼합물의 폭발한계 예측에 폭넓게 적용되기를 기대한다.

• 전자공학회논문지T
• /
• 제36T권2호
• /
• pp.70-76
• /
• 1999

최근에 휴대전화기가 저 연령층까지 널리 보급되어 어린이들의 두부내에 열점(hot-spot)형성문제가 염려되고 있는 실정이다. 전자파의 인체영향이 체온상승의 열적작용에 의한 것이라고 생각한다면 휴대전화기에 의해 발생하는 두부내 국소SAR의 인체영향도 두부의 온도상승과 연관된다고 추정된다. 본 논문은 휴대전화기를 실사용 상황에서 시간대별 두부의 국소부위에 대한 온도변화를 측정하였다. 그 결과 휴대전화기의 통화시작점에서 계속적인 온도상승을 보이다가 통화가 끝나는 시점에서 두부의 국소적인 온도변화는 빠르게 회복되지만 생체전신의 평균온도는 상승함을 알 수 있었다.

• 한국안전학회지
• /
• 제17권4호
• /
• pp.94-100
• /
• 2002

As the use of automatic handling equipment for sensitive semiconductor devices is rapidly increased, manufacturers of electronic components and equipments need to be more alert to the problem of electrostatic discharges(ESD). In order to analyze damage characteristics of semiconductor device damaged by ESD, this study adopts a new charged-device model(CDM), field-induced charged model(FCDM) simulator that is suitable for rapid, routine testing of semiconductor devices and provides a fast and inexpensive test that faithfully represents ESD hazards in plants. High voltage applied to the device under test is raised by the field of non-contacting electrodes in the FCDM simulator, which avoids premature device stressing and permits a faster test cycle. Discharge current and time are measured and calculated. The characteristics of electrostatic attenuation of domestic semiconductor devices are investigated to evaluate the ESD phenomena in the semiconductors. Also, the field charging mechanism, the device thresholds and failure modes are investigated and analyzed. The damaged devices obtained in the simulator are analyzed and evaluated by SEM. The results obtained in this paper can be used to prevent semiconductor devices form ESD hazards and be a foundation of research area and industry relevant to ESD phenomena.

• Environmental Analysis Health and Toxicology
• /
• 제23권4호
• /
• pp.247-256
• /
• 2008

Public perceptions of nanotechnology and its potential risk can be an important measure for the sustainable advances of the technology. We conducted a survey for public (N =599) and experts (N = 165). They answered the same questions and results were analyzed. 74% of the public have not heard about the potential risk of nanotechnology and 77% expected that nanotechnology/materials are not harmful to the human and nature. 74% of experts realized the potential hazards by nanomaterials. The results represented that large perception gab between public and experts has existed in Korea. Interestingly, Korean public thought that nanotechnology is more profitable and less risky than that of American. We suggest that 'now is the best time to give appropriate information on the potential risk of nanotechnology to Korean public without preconception or exaggeration.'

• Nuclear Engineering and Technology
• /
• 제51권1호
• /
• pp.325-336
• /
• 2019

The activity concentrations of $^{226}Ra$, $^{232}Th$, and $^{40}K$ from 102 building materials samples were determined using a high-purity germanium (HPGe) detector. The activity concentrations were evaluated for possible radiological hazards to the human health. The excess lifetime cancer risks (ELCR) were also estimated, and the average values were recorded as $0.42{\pm}0.24{\times}10^{-3}$, $3.22{\pm}1.83{\times}10^{-3}$, and $3.65{\pm}1.85{\times}10^{-3}$ for outdoor, indoor, and total ELCR respectively. The activity concentrations were further subjected to RESRAD-BUILD computer code to evaluate the long-term radiation exposure to a dweller. The indoor doses were assessed from zero up to 70 years. The simulation results were $92{\pm}59$, $689{\pm}566$, and $782{\pm}569{\mu}Sv\;y^{-1}$ for indoor external, internal, and total effective dose equivalent (TEDE) respectively. The results reported were all below the recommended maximum values. Therefore, the radiological hazards attributed to building materials under study are negligible.

• 한국안전학회지
• /
• 제37권6호
• /
• pp.96-101
• /
• 2022

The Occupational Safety and Health Act holds that industrial safety helmets can be used as protective equipment to prevent the risk of injury in fall accidents. To better understand the importance given to PPE for the head, we analyzed the relevant regulations and guidelines in developed countries and reviewed the guidelines on testing safety helmets. The PPE regulations in Korea were notably different from those in other countries. First, except in Korea and Japan, safety helmets were used for protection against falling objects, flying objects, impact, or electric shock. However, the regulations did not recognize safety helmets as a PPE against fall hazards. Second, the impact energy applied on the helmet was within the range 50-100 J, and the helmet could protect only the upper part of the head against hazards such as the impact of falling objects, flying objects, etc. Third, in Korean regulations, the term "fall" was used in relation to the parts where the safety helmet was specified as a fall hazard PPE, unlike in other countries. We propose that the term "fall" should be revised to "shock" in Korean regulations for the safety helmet.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2021년도 봄 학술논문 발표대회
• /
• pp.313-314
• /
• 2021

An old building over 30 years old continue to increase. Therefore, there will be more dismantling of old buildings in the future. Safety management of dismantling works is being strengthened. However, no consideration has been given to the effects of dismantling workers and their residents due to environmental hazards arising from the demolition process. Only spray and dust prevention measures are subject to inspection to minimize dust generation considering civil complaints around the site of dismantling work. In this paper, residential buildings, which account for the largest proportion of old buildings, were collected and identify total airborne bacteria and floating fungi among environmental hazards caused by non-structural dismantling work. Measurement results showed that workers during dismantling work are working in places with 4.8 times more total airborne bacteria than indoor air quality maintenance standards. Related research is needed for the health of dismantling workers.

• Journal of Preventive Medicine and Public Health
• /
• 제21권1호
• /
• pp.152-162
• /
• 1988

Benzene and toluene, which are widely used aromatic hydrocarbons in workplace, are recently proved to cause health hazards due to their toxic effects. This study investigated the influence of toluene on the urinary excretion of benzene metabolite by administering short term exposure limit(STEL) of these compounds(i.e., 13.8mg/kg of benzene and 108.8 mg/kg of toluene) intraperitoneally into Sprague-Dawley rats. After administration, urinary phenol concentration of rat was measured by gas chromatography for every three hours. Data were analyzed by non-parametric statistical methods using Kruskal-Wallis multi-sample test and Mann-Whitney U test. The following results were obtained : 1. Administration of STEL-benzene increased urinary phenol concentration in lats. 2. Urinary phenol concentration was increased logarithmically according to the dosage of benzene. 3. Excretion of phenol in urine was decreased when benzene and toluene were administered simultaneously compared with administering benzene alone. In summary, these results reveal that administration of STEL of toluene has antagonistic effect of urinary excretion of benzene metabolite in rats.

• 한국안전학회지
• /
• 제25권3호
• /
• pp.61-65
• /
• 2010

Most of the chemical reactions performed in the chemical industry are exothermic, meaning that thermal energy is released during the reaction. It is also important to understand the thermal hazards such as thermal stabilities and runaway reactions, which are governed by thermodynamics and reaction kinetics of the mixed materials. The paper was described the evaluation of thermal behavior caused by an exothermic batch process in manufacture of the vinyl acetate resin. The aim of the study was to evaluate the thermal stabilities of raw materials with operating conditions such as a reaction inhibitor, heating rate, reaction atmosphere and the mount of methanol charged in the vinyl acetate polymerization process. The experiments were performed in the differential scanning calorimeter(DSC), C 80 calorimeter, and thermal screening unit($TS^u$). It was suggested that we should provide the thermal characteristics for raw materials to present safe precautions with operating conditions in the vinyl acetate polymerization process.

• 한국안전학회지
• /
• 제24권5호
• /
• pp.13-20
• /
• 2009

The risk assessment of thermal hazard to identify chemical or process hazard during early process developments have been considered. The early identification of thermal hazards associated with a process, such as rapid heats of reaction, exothermic decompositions, and the potential for thermal runaways before any large scale operations are undertaken. This paper presents to evaluate the safe operating parameters/envelope for exist plant operations. The assessment of thermal hazard with operating conditions such as amount of process materials, inhibitor, and catalyst on esterification process in manufacture of concrete mixture agents are described. The experiments were performed by a sort of calorimetry with the Multimax reactor system as a screening tool. The aim of the study was to evaluate the thermal risk of process material and mixture in terms of safety security to be practical applications in esterification process. It suggested that we should provide the thermal hazard of reaction materials to present safe operating conditions with cause of accident through this study.