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Chiu, C.W.,Ng, Alfreda The Korean Institute of Electrical Engineers 2013 The Journal of International Council on Electrical Vol.3 No.1
Primary distribution substation busbar forms an electrical node where incoming sources and outgoing circuits come together, feeding in and sending out power directly to customers. If a busbar fails or trips, it will lead to the supply interruption to a large number of customers fed by the outgoing circuits connected to the busbar. The interruption time will be much longer because the supply restoration can only be done at downstream level through multiple switchings. Therefore, a reliable and discriminative busbar protection is crucial to protect this important piece of equipment in the distribution network and to achieve high supply reliability. Proper protection design of a distribution network should also cater for circuit breaker failure when an external fault occurs. When this happens to a circuit breaker connected to a busbar, tripping out of the busbar to clear the fault is inevitable. For this reason, breaker failure protection is normally incorporated into the busbar protection scheme of a primary distribution substation as a total solution. This paper describes the HK Electric's distribution protection system that employs a simple yet effective rough balance differential principle to achieve busbar protection and breaker failure protection with proper fault discrimination. The paper also compares the merits and drawbacks of different busbar and breaker failure protection schemes adopted by us and some other utilities.
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Homocysteine as a Diagnostic and Etiopathogenic Factor in Children with Autism Spectrum Disorder
Jan Jozefczuk,Wiktoria Kasprzycka,Rafa1 Czarnecki,Alfreda Graczyk,Pawel Jozefczuk,Krzysztof Magda,Urszula Lampart 한국식품영양과학회 2017 Journal of medicinal food Vol.20 No.8
Substantial characteristics of autism are cognitive and psychophysical disorders. Etiopathogenetic factors are thought to be responsible for development of autism in children with genetic predisposition as well as have their effect on the severity of the disorders. The main problem of early identification of patients affected by autism spectrum disorder is that there are no clear diagnostic criteria. The aim of our study was assessment of hair magnesium and serum homocysteine concentrations in children with autism. The presented work is a continuation of previous study in which we investigated the influence of disturbances in magnesium and homocysteine levels in children with autism, performed on a new, larger group of patients. One hundred and forty children had hair magnesium levels analyzed, as well as blood serum levels of homocysteine and magnesium. Hair magnesium analysis was performed using a flame atomic absorption spectrometer, blood serum homocysteine determination was performed using a radioimmunological method, and blood serum magnesium level was determined using a biochemical method. Our research showed normal magnesium blood levels and significantly high homocysteine levels and very low hair magnesium levels, low concentration of hair magnesium progresses with age. Our hypothesis is that magnesium deficiency, as a relevant epigenetic factor, might be decreasing methylation of homocysteine, therefore decreasing genome transcription and lowering the synaptic plasticity. We suggest that analysis of hair magnesium and serum homocysteine levels might be useful in identification of children with autism spectrum disorder, as well as control of its treatment. Obtained results and performed analysis might therefore justify supplementation of magnesium among children with autism.
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배기형 해부테이블과 급배기 장치를 설치한 해부실습실의 포름알데히드 농도 평가
서제훈(Je Hoon Seo),현종아(Jong-a Hyun),오민광(Min-Kwang Oh),김지영(Ji Young Kim),김용대(Yong-Dae Kim),김동운(Dong-Woon Kim),Alfreda Stadlin,손현준(Hyun Joon Sohn),이은영(Eun Young Lee) 대한체질인류학회 2016 해부·생물인류학 (Anat Biol Anthropol) Vol.29 No.3
해부실습을 위한 시신의 방부처리에 사용하는 포름알데히드는 인체에 유해하다. 국내외에서는 산업 현장에서 근로자들의 건강을 보호할 목적으로 포름알데히드의 허용농도를 규정 또는 권고하고 있다. 고용노동부의 시간가중평균농도 (time weighted average, TWA)의 허용범위는 0.5 ppm (0.75 mg/㎥) 이하이고 단시간노출농도 (short term exposure limit, STEL)는 1 ppm (1.5 mg/㎥) 이하이며 미국과 유럽의 TWA는 0.3~2 ppm 사이이다. 이 연구는 배기형 해부테이블과 급배기 장치를 설치한 해부실습실에서 포름알데히드의 공기 중 농도를 측정하여 국내외 포름알데히드 기준 농도와 비교하였다. 배기형 해부테이블은 elevated dissection table을 채택하여 10대를 설치하였고, 급배기 장치는 천장에 급기구 18개와 해부실습실 양쪽 벽면 아래쪽에 배기구 5개씩 10개를 설치하였다. 포름알데히드 농도 측정은 이동식 측정기인 Formaldemeter로 바닥에서 1.5 m 높이에서 실내 5부위와 시신 바로 위에서 측정하였다. 해부실습실 실내 5부위의 포름알데히드 평균농도는 0.31 ppm (0.45 mg/㎥)이었고, 0.21~0.41 ppm (0.26~0.51 mg/㎥)의 분포를 보였다. 시신 바로 위에서의 포름알데히드 평균농도는 0.45 ppm (0.56 mg/㎥)이었고, 0.31~0.64 ppm (0.39~0.80 mg/㎥)의 분포를 보였다. 포름알데히드의 TWA는 5시간 기준으로 해부실습실 실내가 평균 0.19 ppm (0.24 mg/㎥)이었고, 0.13~0.26 ppm의 분포를 보였다. 시신 바로 위의 TWA는 평균 0.28 ppm (0.35 mg/㎥)이었고, 0.19~0.40 ppm의 분포를 보였다. 배기형 해부테이블과 급배기 장치를 설치한 해부실습실은 고용노동부의 포름알데히드 농도 기준을 충족하였고, 대부분의 외국 기준도 충족하는 수준이었다. 이 연구는 국내 의과대학의 해부실습실 환경 개선 선도 모델의 첫 공기 질 평가로서 다른 의과대학 해부실습실의 공기 중 포름알데히드 농도의 기준값으로 활용될 뿐만 아니라 환경 개선 공사를 위한 설계 및 시공의 참고자료로 활용될 것으로 기대된다. Formaldehyde (FA) used for preserving the body for anatomy dissection is harmful to the human body. In many countries, for the purpose of protecting the health of workers in the industrial field, the maximal allowable air concentration of FA has been set. The threshold limit values of time weighted average (TLV-TWA) and short-term exposure limit (TLV-STEL) of FA recommended by Ministry of Employment and Labor (MOEL) of Korea are less than 0.5 and 1 ppm, respectively. In the United States and Europe, TLV-TWAs of FA are recommended at between 0.3 and 2 ppm. In this study, we compared the air concentration of FA to domestic and foreign standards of FA in an anatomy laboratory equipped dissecting tables with inbuilt exhaust and an air diffuser/return system. We installed ten elevated dissection tables, 18 air diffusers on the ceiling, and 10 air returns at the bottom of both side walls. The concentration of FA was measured at five sites in the anatomy laboratory and above the cadavers on the dissecting tables at a height of 1.5 m from the floor using a Formaldemeter. The average concentration of FA in the anatomy laboratory (five sites) was 0.31 ppm (0.45 mg/㎥), range 0.21 to 0.41 ppm (0.26~0.51 mg/㎥). The average concentration of FA above the cadavers was 0.45 ppm (0.56 mg/㎥), range 0.31 to 0.64 ppm (0.39~0.80 mg/㎥). The average TWA of FA in the anatomy laboratory was 0.19 ppm (0.24 mg/㎥), range 0.13 to 0.26 ppm. The average TWA of FA above the cadavers was 0.28 ppm (0.35 mg/㎥), range 0.19 to 0.40 ppm. The anatomy laboratory dissecting tables equipped with inbuilt exhaust and air diffuser/return system met the criteria of the FA concentration recommended by MOEL of Korea and most foreign countries. This study was the first evaluation of the air concentration of FA in an anatomy laboratory equipped dissecting tables with inbuilt exhaust and an air diffuser/return system in Korea. We expect it will be not only used as a standard of comparison for anatomy laboratories, but as a reference for design and construction to improve air quality in Korean Medical Colleges.
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