• 한국가스학회지
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• 제18권3호
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• pp.75-81
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• 2014

이소부틸알코올의 안전한 취급을 위해, 폭발한계는 문헌을 통해 고찰하였으며, 인화점과 발화지연시간에 의한 자연발화온도는 장치를 이용하여 측정하였다. 공정에서는 이소부틸알코올의 폭발하한계는 1.7 Vol.% 그리고 상한계는 10.9 Vol.%가 사용되고 있다. 인화점의 경우 밀폐식 장치인 Setaflash와 Penski-Martens에 의한 하부인화점은 각 각 $25^{\circ}C$와 $30^{\circ}C$로 측정되었으며, 개방식인 Tag와 Cleveland 에서는 각 각 $36^{\circ}C$와 $39^{\circ}C$로 측정되었다. ASTM E659 장치를 사용하여 자연발화온도와 발화지연시간을 측정하였고, 이소부틸알코올의 최소자연발화온도는 $400^{\circ}C$로 측정되었다.

• 한국산업보건학회지
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• 제19권4호
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• pp.412-422
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• 2009

This study was conducted to assess exposure to musculoskeletal disorder(MSD) risk factors in hospital personnel who performed non-routinized work tasks. A tool ("PATH-KOSHA" version) was newly revised from PATH(Posture, Activity, Tools and Handling) method and uploaded into a personal digital assistant(PDA). The version was used, on a basis of direct-observation, to collect PATH data at the 2 hospital settings in different regions. Job analysis was performed to get various information (e.g., work and rest time, task type) as well. The data collected were visually checked for data cleaning and stored for future data analysis. A total of 1,992 PATH observations were made for 37 hospital workers. Exposure levels varied across 18 items of the MSD risk factors. The highest percent time spent on non-neutral postures was 53% for wrist deviation, followed by 47%(pinch grip), 35%(trunk posture), 23%(neck posture), and 20%(shoulder/arm posture). The highest percent time spent among hand activity level(HAL) variables was 55% for HAL-cat2 (HAL: 3.3 - <6.7). The percent time of items with respect to both loads with more than 5kg and contact stress was less than 4%. Vibration was not exposed in the study workers. Different aspects were discussed for findings. The study results showed that wrist deviation was highest in percent time spent on awkward posture while HAL-cat2 was highest in hand repetition. The study suggests that distal upper extremity posture and HAL should be primarily addressed and controlled in non-routinized work including the hospital settings.

• 한국입자에어로졸학회지
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• 제12권3호
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• pp.51-56
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• 2016

Due to recent development in nanotechnology and increasing usage and production of nanomaterials, numerous studies related to environment, sanitation and safety handling of nanoparticle are being conducted. Since nanoparticles can be easily absorbed into human bodies through breathing process, based on their toxic substances and their large specific surface, these particles can cause serious health damage. Therefore, to reduce nanoparticle emissions, nanofiltration technology is becoming a serious issue. Filtration is a separation process during which a fluid passes through a barrier by removing the particles from the stream. Barrier filters can be made of various materials and shapes. One of the most common type of barrier filter is the fibrous filter. Fibrous filters are divided in two types: nonwoven and woven fabrics. Polypropylene is a thermoplastic material, used as a base material for melt blown nonwoven fabric. In this study, we examined filtration property of KCl nanoparticles with a mean particle diameter of 75 nm using multilayer meltblown filter samples. These experiments verify that the penetration of nanoparticle in the filter correlate with pressure drop; the meltblown layer MB1 has the greatest effect on dust collection efficiency of the filter. Among all tested samples, dust collection efficiency of 2-layer filter was best. However, when considering the overall pressure drop and dust collection efficiency, the 4-layer filter has the highest quality factor for particles smaller than 70 nm.

• 에너지공학
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• 제24권4호
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• pp.18-23
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• 2015

인화점은 인화성에 따라 가연성 액체들을 분류하기 위해 사용된다. 인화점은 인화성 액체를 안전하게 저장, 취급 수송하기 위한 중요한 정보이다. Tag 개방식 장치를 이용하여 두 개의 이성분계 혼합물($CCl_4+o-xylene$ and $CCl_4+p-xylene$)의 인화점을 측정하였다. 또한 라울의 법칙, UNIQUAC 식, 경험식을 이용하여 인화점을 계산하여 그 값을 측정치와 비교하였다. 이 중 경험식에 의한 인화점 계산치가 가장 측정치를 잘 모사하였다.

• 한국가스학회지
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• 제16권3호
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• pp.8-15
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• 2012

이소프로필 알코올의 안전한 취급을 위해 $25^{\circ}C$에서 폭발한계를 고찰하였고, 실험장치를 이용하여 하부인화점, 상부인화점, 연소점 그리고 발화지연시간에 의한 발화온도를 측정하였다. 그 결과, 공정의 안전을 위한 이소프로필 알코올의 폭발 하한계는 2.0 vol%이고, 상한계는 12.0 vol%로 문헌을 통해 판단되었다. 하부인화점은 밀폐계에서 $12{\sim}14^{\circ}C$와 개방식에서 $18{\sim}19^{\circ}C$이었고, 상부인화점은 $38^{\circ}C$로 측정되었다. ASTM E659 장치를 사용하여 측정된 최소자연발화온도는 $463^{\circ}C$이었다.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권5호
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• pp.281-285
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• 2023

Background: Dentists bend needles prior to certain injections; however, there are concerns regarding needle fracture, lumen occlusion, and sharps handling. A previous study found that a 30-gauge needle fractures after four to nine 90° bends. This fatigue life study evaluated how many 90° bends a 30-gauge dental needle will sustain before fracture when bent using a needle guide. Methods: Two operators at Element Materials Technology, an independent testing, inspection, and certification company tested 48 30-gauge needles. After applying the needle guide, the operators bent the needle to a 90° angle and expressed the anesthetic from the tip. The needle was then bent back to a 0° angle, and the functionality was tested again. This process was repeated until the anesthetic failed to pass through the end of the needle due to fracture or obstruction. Each operator tested 24 needles (12 needles from each lot), and the number of sustained bends before the needle fracture was recorded. Results: The average number of sustained bends before needle failure was 40.33 (95% confidence interval = 37.41-43.26), with a minimum of 20, median of 40, and a maximum of 54. In each trial, the lumen remained patent until the needle fractured. The difference between the operators was statistically significant (P < 0.001). No significant differences in performance between needle lots were observed (P = 0.504). Conclusion: Our results suggest that using a needle guide increases the number of sustained bends before needle fracture (P < 0.000001) than those reported in previous studies. Future studies should further evaluate the use of needle guides with other needle types across a variety of operators. Furthermore, additional opportunities lie in exploring workplace safety considerations and clinical applications of anesthetic delivery using a bent needle.

• 한국가스학회지
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• 제19권4호
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• pp.8-14
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• 2015

화학산업에서 다양하게 사용되고 있는 2-methyl-1-butanol의 안전한 취급을 위해서 인화점과 최소자연발화온도를 측정하였다. 2-methyl-1-butanol의 폭발하한계는 실험에서 얻어진 하부인화점을 이용하여 계산하였다. Setaflash 밀폐식은 $40^{\circ}C$, Pensky-Martens 밀폐식은 $44^{\circ}C$ 그리고 Tag 개방식은 $49^{\circ}C$, Cleveland 개방식에서는 $47^{\circ}C$로 측정되었다. ASTM E659 장치에 의한 최소자연발화온도는 $335^{\circ}C$로 측정되었다. 측정된 하부인화점 $40^{\circ}C$에 의한 폭발하한계는 1.30 Vol.%로 계산되었다. 폭발한계는 측정된 인화점이나 문헌에 제시된 인화점을 이용하여 예측 가능함을 알 수 있었다.

• 한국식품위생안전성학회지
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• 제34권1호
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• pp.1-12
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• 2019

신선한 농산물 섭취와 관련된 많은 장점들이 전세계적으로 발표되고 있으며, 지속적인 섭취를 장려하고 있다. 일반적으로 과일과 채소는 최소한으로 가공되기 때문에 천연의 성분들이 건강을 증진시키는 역할을 하기도 하지만 그만큼 질병을 일으킬 수 있는 매개체가 존재할 수 있는 가능성이 매우 높다. 세계 보건기구 (WHO)의 보고서에 따르면 10명 중 1명이 식품에 의해 발생하는 질병으로 고통 받고 있으며, 전 세계적으로 매년 42만 명이 식중독으로 사망하는 것으로 밝혀졌다. 이러한 신선 식품은 농장에서 수확할 때부터 소비자의 식탁에 오르기까지 다양한 경로에서 쉽게 오염 될 수 있다. 본 리뷰논문에서는 신선식품에 의해 발생할 수 있는 질병을 이해하기 위해 화학적, 생물학적, 그리고 물리학적 위험요소로부터 식중독을 일으키는 원인과, 증상, 그리고 검출 방법에 대해서 기술 하였다. 화학적 위험요소의 대표적인 예로는 농약(살충제, 살균제, 및 제초제), 천연 독소 (곰팡이 독소 및 식물 독소), 그리고 중금속 (수은 및 카드뮴) 등이 있으며 이는 크로마토그래피 및 나노 기술 등을 이용하여 검출 할 수 있다. 하지만, 여러 실험에도 불구하고 화학적 위험 요소는 그 구조가 다양하기 때문에 위험 요소를 검출하는 하나의 표준 방법을 수립하기 힘들다. 신선한 과일과 채소는 영양분과 수분이 풍부하기 때문에 박테리아성 병원균 (Salmonella, E. coli O157: H7, Shigella, Listeria monocytogenes, Bacillus cereus), 바이러스 또는 기생충에 의해 쉽게 오염이 되며, 이를 검출하기 위해 주로 다양한 분자 생물학적 기술이 사용되고 있다. 마지막으로 물리적 위험요소인 유리, 금속, 자갈 등과 같은 매개체는 가공 공정 중에 식품에 유입되어 소비자에게 신체적 상해를 줄 수 있다. 이러한 위험요소를 줄이기 위해서 X-선 검사와 같은 투시 시스템을 이용하여 위해물질을 탐지하거나, 생산에 관여하는 직원 교육을 통해 2차 감염을 줄일수 가 있다.

• 한국가스학회지
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• 제19권5호
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• pp.54-60
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• 2015

최소자연발화온도는 가연성물질이 주위의 열에 의해 스스로 발화하는 최저온도이다. 최소자연발화온도는 유기혼합물중 가연성 액체혼합물의 안전한 취급을 위해서 중요한 지표가 된다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 노말데칸과 에틸벤젠 계의 최소자연발화온도를 측정하였다. 이성분계를 구성하는 노말데칸과 에틸벤젠의 최소자연발화온도는 각 각 $210^{\circ}C$, $430^{\circ}C$로 측정되었다. 그리고 측정된 노말데칸과 에틸벤젠 혼합물의 최소자연발화온도는 제시된 식에 의한 예측값과 약 $11^{\circ}C$평균절대오차에서 일치하였다.

• 농촌의학ㆍ지역보건
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• 제6권1호
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• pp.13-24
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• 1981

This study was conducted with 478 farm households located in Pyongtaek Gun of Gyonggi Do, Chongju City and Chongwon Gun of Chung Buk Do, and Hongchon Gun of Gangwon Do for the period of 10, September through 20, October 1980. It dealt with general features of the farmhouseholds, their practices of handling and using pescides, and relationship between safe use of pesticides and poisoning experiences. The results of the study are summarized as follows: 1. Of the total, 63.2% purchased pesticides mainly through the Agricultural Coops, and 95.4% transported them home separately from other goods. 2 Pesticides were sold contained mainly in glass bottles and paper bags. 3. Mixing of the respodents (87.5%) stored pesticides in sheds, warehouses and boxes. 4. Mixing containers and measuring tools were not used by the majority of the group studied. This indicates that there exist serious problems of safety and accuracy with regard to use of pesticides. 5. As to pesticide protective devices, gloves, respirators, goggles and boots were not used in general. Even in case of using them, their quality was not satisfactory. 6. Among the interviewees, 4.2% did not read pesticide label, 33.9% did not wash immediately when pesticide was spilled on the skin, 48.4% did not care the wind direction during pesticide application, and 17.0% did not wash hands when smoking a cigarette while pesticide is being handled. 7. Of the total, 40.4% were found to harvest vegetables within 10 days from the date of pesticide application, which indicates their unawareness of possible hazards by pesticide residues. 8. Empty pesticide containers or bags were not properly disposed of by majority of the respondents. Furthermore, impacts on the environment by the misuse or abuse of pesticides were not understood by 67.6% 9. Of the interviewees, 48.7% were found to have not received instructions on safe use of pesticides. 10. The rate of pesticidal poisoning experience was about 28.0% if minor symptoms excluded, and it rose to about 44.0% if included. Meanwhile, the rate of pesticidal poisoning tends to increase with the size of farm. 11. The study failed to show a statistically significant relationship between the rate of pesticidal poisoning and use of mixing container and/or measuring tools. However, use of gloves showed a statistical significance on the rate of pesticidal poisoning. 12. Among the poisoned cases, 19.0% were cared for in either hospitals or clinics.