The wind turbine blades should be designed to possess a high stiffness and should be fabricated with a light and high strength material because they serve under extreme combination of lift and drag forces, converting kinetic energy of wind into shaft work. The goal of this study is to understand the basic knowledge required to curtail the process time consumed during the construction of small wind turbine blades using carbon fiber reinforced polymer (CFRP) prepeg composites. The configuration of turbine rotor was determined using the QBlade freeware program. The fluid dynamics module simulated the loads exerted by the wind of a specific speed, and the stress analysis module predicted the distributions of equivalent von Mises stress for representing the blade structures. It was suggested to modify the shape of test specimen from ASTM D638 to decrease the variance in measured tensile strengths. Then, a series of experiments were performed to confirm that the bladder compression molded CFRP prepreg can provide sufficient strength to small wind turbine blades and decrease the cure time simultaneously.

본 연구는 개정된 소 도체 등급판정 세부기준이 개정 목표에 부합되는지를 평가하기 위해 실시되었다. 본 연구에서는 기초 데이터를 바탕으로 데이터의 분포를 도출하고, 도출된 분포를 바탕으로 미래 데이터를 추출하여 이를 분석하는 몬테카를로(Monte Carlo) 방법론을 활용하였다. 축산물품 질평가원의 2019년 1월 2일부터 2019년 5월 31일까지 등급판정을 받은 한우 거세 비육우의 도체정보(n=187,279)를 이용하여 각 도체성적의 분포와 상관관계를 도출하였다. @risk 소프트웨어를 이용하여 10만 개의 가상 도체 데이터를 Latin hypercube 방법으로 추출하여 몬테카를로 시뮬레이션을 실시하고, 각 변수들이 육량지수, 육량등급, 육질등급에 미치는 영향력을 평가하였다. 시뮬레이션 결과, 육량지수는 현행 등급판정 기준과 개정된 기준에서 모두 도체중량이 증가함에 따라 감소하는 것으로 나타났으며 각 변수들에 대한 민감도는 두 기준이 유사하였다. 개정된 기준에서는 도축월령이 증가함에 따라 그 정도는 미미하지만 육량지수 및 육량등급이 저하되는 것으로 나타났다(P < 0.001). 현행 등급판정 기준에서는 그 밖의 도체성적이 동일할 때, 육질등급은 배최장근단면적과 도축월령이 증가할수록 개선되고(P < 0.01), 등지방두께와 도체중량은 육질등급에 유의적인 영향을 미치지 않는 것으로 나타났다. 그러나 개정된 등급판정 기준에서는 육질등급이 모든 도체성적 및 도축월령과 유의적인 관계를 갖는데(P < 0.01), 그 밖의 도체성적이 동일하다면, 도체중량이 클수록, 등지방두께가 얇을수록, 배최장근단면적이 적을수록, 도축월령이 적을수록 육질등급이 개선되는 것으로 나타났다. 결론적으로 새로운 ‘소 도체 등급판정 세부기준’은 도체중량의 증가에 따라 육량등급을 증가시키는 것은 아니나, 현행 기준에 비해 한우의 사육기간을 단축시키는 효과는 클 것으로 기대된다.

Many people have often reused their disposable respirator multiple times due to reasons of economy and purchasing inconvenience. However, multiple use of a disposable respirator may lead to an adverse effect of its protection performance. In this study, we aimed to determine changes in the protection performance of disposable respirators related to multiple use and to suggest the appropriate number of times of use. The masks of the brands T and Y were selected in this study, respectively. A mask of each brand was used for testing at the same time and place for two hours per day. The protection performance of each disposable mask was tested after consecutive use on days two, three, and four. The protection performance tests for each used mask following wear on a mannequin were performed in the laboratory using GRIMM’s fine dust monitoring device and TSI’s nebulizer. The concentration of PM10, PM2.5, and PM1.0 inside and outside the mask was measured. The filtration rate was calculated and the results were analyzed using the SAS statistical program. The protection rates of the brandnew masks of T and Y brands (blank test) were 80% and 60%, respectively. After one-day usage, the protection rates of the brand-new T and Y branded masks significantly decreased from 80% to 60% and from 60% to 50%, respectively. Rather, the slight drops of protection rate were observed after two or more days of respirator use. Our findings indicate that the change of protection performance could occur after one-time use. It would not be recommended to use disposable respirators several times in terms of in terms of protecting human health from environmental hazards.

As indoor activities continue to increase, the importance of indoor air is emphasized. Moreover, children's activities are emphasized as being vulnerable. In this study, vocal organic compounds (VOCs) and CO2 in the indoor air were analyzed among children aged 4 to 7 years attending day care centers in Seoul. In the case of VOCs, the average concentration measured during a period of 24 hours in an asthmatic home was 143.9 (μg/m3). The average concentration measured during a period of 24 hours in the asthma and rhinitis home was 146.7 (μg/m3). In CO2, the average concentration measured during a period of 24 hours in the asthmatic home was 665.9 (ppm). The average concentration measured during a period of 24 hours in the asthma and rhinitis home was 695.9 (ppm). In this study, asthma symptoms increased as the concentration of indoor pollutants increased. Exposure of VOCs (μg/ m3) and CO2 (ppm) among environmental factors shows that respiratory symptoms such as asthma can be induced.

Mold grows more easily when humidity is higher in indoor spaces, and as such is found more often on wetted areas in housing such as walls, toilets, kitchens, and poorly managed spaces. However, there have been few studies that have specifically assessed the level of mold in the indoor spaces of water-damaged housing in the Republic of Korea. We investigated the levels of airborne mold according to the characteristics of water damage types and explored the correlation between the distribution of mold genera and the characteristics of households. Samplings were performed from January 2016 to June 2018 in 97 housing units with water leakage or condensation, or a history of flooding, and in 61 general housing units in the metropolitan and Busan area, respectively. Airborne mold was collected on MEA (Malt extract agar) at flow rate of 100 L/min for 1 min. After collection, the samples were incubated at 25oC for 120 hours. The cultured samples were counted and corrected using a positive hole conversion table. The samples were then analyzed by single colony culture, DNA extraction, gene amplification, and sequencing. By type of housing, concentrations of airborne mold were highest in flooded housing, followed by water-leaked or highly condensed housings, and then general housing. In more than 50% of water-damaged housing, the level of airborne mold exceeded the guideline of Korea's Ministry of Environment (500 CFU/m3). Of particular concern was the fact that the I/O ratio of water-damaged housing was greater than 1, which could indicate that mold damage may occur indoors. The distribution patterns of the fungal species were as follows: Penicillium spp., Cladosporium spp. (14%), Aspergillus spp. (13%) and Alternaria spp. (3%), but significant differences of their levels in indoor spaces were not found. Our findings indicate that high levels of mold damage were found in housing with water damage, and Aspergillus flavus and Penicillium brevicompactum were more dominant in housing with high water activity. Comprehensive management of flooded or water-damaged housing is necessary to reduce fungal exposure.

The aim of this study was to examine indoor fungal concentration and fungal volatile organic compounds(VOCs) in single-person households. A total of 22 houses occupied by one person were investigated in this study. 19 VOCs detected in the field were estimated as fungi-derived VOCs through a review of the literature, and 11 VOCs were confirmed as fungal VOCs by laboratory experiments. Exposure to fungal VOCs in the indoor environment has been confirmed to be highly influenced by airborne fungal concentration and indoor humidity. 3-octanone was characterized by a clear generation profile in Aspergilus versiocolor, and n-decane in Pencillum chrysogenum. ntetradecane emitted by Stachybotrys chartarum exhibited a tendency to occur consistently. The observations made in this study demonstrated that single-person households can easily be exposed to fungi, and MVOCs can be used as an indicator of fungal exposure in indoor environments.

Exposure to the indoor air pollutants could be associated with the risk of developing atopic dermatitis, including allergic symptoms and exacerbations. A total of Fifty homes who had a past or current symptoms of atopic dermatitis were enrolled in the study. To rate the levels of environmental factor, we measured concentrations of PM2.5, PM10, Heavy metals XRF (X-Ray Fluorescene), Bacteria (CFU/m3), mold (CFU/m3) in dust of the children’s houses. The prevalence of atopic dermatitis in children is increasing especially in Urban areas. Exposure to levels of indoor environmental factor and air pollutants has been related to atopic dermatitis development. The house dust were higher for the results of atopy, asthma patients analyzed fungi and bacteria, resulting XRF measurements Cr (chromium), As (arsenic), Br (bromine), Cd (cadmium), Hg (mercury), Pb (lead) etc. this has a significant relationship. Recent studies have shown that indoor air pollutants control is beneficial in reducing atopic dermatitis prevalence and development. Urban areas children are exposed to kinds of indoor environmental factor and air pollutants that may lead to atopic dermatitis development.

As a result of frequent occurrence of serious industrial accidents due to chemical substances, Korea Occupational Safety & Health Agency has been implementing the PSM system (process safety management) since 1996, and the target sites are required to submit process safety reports. In the semiconductor business, which is becoming smaller and more integrated as the technology advances, many of these hazardous chemicals are used. Most of the semiconductor sites are PSM target sites, and many devices are included in the PSM target equipment. This study optimizes the introduction and setup process of new equipments in the semiconductor workplace using harmful hazardous materials, and conducted an empirical study on the improvement of the safety risk, focusing on the S group semiconductor business, and applied the common standard of work under the PSM system This is an example of improving the risk of leakage of toxic gas components and waste of rework by arranging functions and risks in the space centering method

An up-flow botanical bioreactor was proposed as an economical and environmentally-friendly control process to remove the odorants, specifically ammonia and hydrogen sulfide, in exhaust gas. Liriope Platyphylla and Hedera Helix were selected as the test plants, and were put into the lab-scale reactor filled with the ceramic media. During 52 days of operation with ammonia loading of 1.16 g/m3·d, Liriope Platyphylla showed better performance in ammonia removal. Liriope Platyphylla was further tested by the simultaneous loading of 6.96 g/m3·d for ammonia and 1.00 g/m3·d for hydrogen sulfide. Microbial activity in the botanical reactor was greatly enhanced by mixed odorants rather than single odorants, and can contribute to removing odor in the exhaust gas. Biological uptake by plants reached up to 20% of total nitrogen loading to the botanical reactor.

다양하고 풍부한 내용과 의미를 지닌 『삼국연의』 속 아이들과 관련된 일화는 소설 속의 소설이라 할 수 있다. 본고에서는 소설 속에 나오는 아이들의 일화를 덕행, 언변, 문제 해결, 기타 등 네 가지로 분류하여, 난세에 아이들도 언변과 지혜를 다하고 때로 분발과 처세로 살 아나갔음을 살펴보았다. 소설가는 정사와 필기 등의 기록 가운데 일정한 선택과 배제의 기준 에서 취사선택하였다. 소설은 삼국의 대립과 통일이라는 줄거리에 집중하여 그와 관련된 인 물들의 일화를 수집하였지만, 한편으로 삼국시대에 새로 등장한 현학과 죽림칠현 등 문화적 현상은 될수록 배재하였다. 아이들의 일화는 소설적 기능도 일정 정도 수행하고 있었다. 유년 의 언행은 성년의 활동을 이해하는데 도움을 주며, 인물의 성격을 부여하는데 근본적인 특징 으로 제시되었다. 그 결과 독자는 인물을 다방면에서 볼 수 있어 인물에 대한 풍부한 형상을 제공받게 된다. 더불어 유년의 언행이나 사건은 이후 일어날 일의 암시와 복선으로 작용하기 도 하였다. 또 아이들의 일화는 소설의 주제와 의미를 심화시키는 효과를 발휘하기도 했다.