• Biomedical Science Letters
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• v.29 no.4
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• pp.256-262
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• 2023

The purpose of this study is to investigate microbial contamination in water purifiers from two universities (A and B) in Chungcheong region and to evaluate about the harmfulness of the isolated bacteria to the human. The degree of microbiological contamination of six water purifiers at university A was investigated three times from July 2018 to September 2019, and nine water purifiers at university B were investigated in 2023. The isolated bacteria were biochemically identified using an API kit and Vitek-2 system, and then the bacteria were identified to the species level using MALDI-TOF MS. In addition, the possibility of human infection of the isolated bacteria was evaluated through a literature search. In July 2018 and September 2019, the number of bacteria isolated inside the faucet was below the acceptable standard for hot water, but exceed for cold water in all water purifiers. In January and September 2019, bacteria exceeding the acceptable standards were isolated nine times from the cold water of six water purifies (a total of 12 water purifiers). Bacteria identified by MALDI-TOF MS included anaerobic bacteria (Clostridium novyi, Clostridium themopalmarium etc.), Gram-positive bacilli (Microbacterium testaceum, Arthrobacter woluwensis etc.), and Gramnegative bacilli (Acinetobacter nosocomialis, Comamonas kerstersii etc.), which are difficult identify by biochemical methods. In conclusion, bacteria exceeding the acceptable standard were isolated from the cold water of most of the water purifiers. Most of the isolated bacteria were low-pathogenic bacteria from natural environment, but opportunistic bacteria that can cause infection in humans were also isolated from some water purifiers.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.2878-2887
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• 2021

As the amount of fission product released from ISLOCA was overestimated because of conservative assumptions in the past, several studies have been recently conducted to evaluate the actual release amount. Among several pathways for the ISLOCA, most studies were focused on the pathway with the highest possibility. However, different ISLOCA pathways may have different fission product release characteristics. In this study, fission product behavior was analyzed for various pathways at the Westinghouse two-loop plant using MELCOR. Four pathways are considered: the pipes from a cold leg, from a downcomer, from a hot leg to the outlet of RHR heat exchanger, and the pipe from the hot leg to the inlet of RHR pump (Pathway 1-4). According to the analysis results, cladding fails at around 2.5 h in Pathways 1 and 2, and on the other hand, about 3.3 h in Pathways 3 and 4 because the ISLOCA pathways affect the safety injection flow path. While the release amount of cesium and iodine ranges between 20 and 26% in Pathways 1 to 3, Pathway 4 allows only 5% to the environment because the break location is submerged. Also, as more than 90% of cesium released to the environment passes through the personnel door, reinforcing the pressure capacity of the doors would be a significant factor in the accident management of the ISLOCA.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.5
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• pp.872-882
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• 2017

There are no specific guidelines on how to control the heat input for the heat generating smart base layer. This study investigated the mode of actuating heat pad attached to the base layer by performing a human wear test in a cold environment. Subjects participating in the test wore T-shirts, jumper and pants on the base layer with heating pads. Skin temperature, total time of heating and the number of switching for the heating mode were observed as the subject controlled the heating mode voluntarily. The comfortable range of skin temperature on the abdomen was larger than on the lower back. The subject felt hot and turned off the switch when the mean skin temperature of the abdomen was $48.8^{\circ}C$ and the lower back was $40.1^{\circ}C$. The total heating time and the number of actuating switching were larger for women than men. The voluntary action of heating for men with high cold sensitivity was significantly different from men with low cold sensitivity. Therefore, it is necessary (depending on gender and cold sensitivity) to set the heating mode differently for the automatic heat control of a future smart base layer.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1059-1064
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• 2008

The present study is to reduce the thermal phenomena and stack effect of nude elevator of the high-rise building used CFD simulation. Since many High-rise buildings used the curtain-wall glass, thermal phenomena and stack effect can easily occur at hot and cold season, respectively. The simulation has been conducted and verified for the effects of the amount of suppling air to the environment of the inside nude elevator shaft. The results of simulations show that the problems due to the thermal and stack effect will be reduced by enforced ventilation or natural ventilation and those will be presented by temperature and velocity profiles and pressure differences.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.35-43
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• 2021

With the rapid urbanization and growing energy use intensity in the built environment, the glazed curtainwall has become ever more important in the architectural practice and environmental stewardship. Besides its energy efficiency roles, window has been an important transparent component for daylight penetration and a view-out for occupant satisfaction. In response to the climate crisis caused by the built environment, this research focuses on the study of net-zero energy retrofitting by using a new building integrated photovoltaic (BIPV) curtainwall as a sustainable alternative to conventional window systems. Design variables such as building orientations, climate zones, energy attributes of BIPV curtainwalls, and glazed area were studied, to minimize energy consumption and discomfort hours for three cities representing hot (Miami, FL), mixed (Charlotte, NC), and cold (Minneapolis, MN). Parametric analysis and Pareto solutions are presented to provide a comprehensive explanation of the correlation between design variables and performance objectives for net-zero energy retrofitting applications.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1479-1485
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• 2018

A number of experiments have been performed on light slowing and stopping in the electromagnetically induced transparency (EIT) media of hot atomic gases where the Doppler-shift may add detunings to the field frequencies in an inhomogeneous fashion. We provide here a theoretical analysis as to the effect of such a Doppler-broadened environment on the dynamics of the system in comparison to a cold atomic medium. We will show that one of the most critical factors in the formation of a stationary light pulse is the enhancement of the excited-state decay rate caused by the collisions between the atoms of the medium and the molecules of the buffer gas.

• Clinical and Experimental Pediatrics
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• v.64 no.12
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• pp.632-641
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• 2021

Background: Over the past few decades, various goals have been defined to reduce the mortality of children caused by acute lower respiratory infections (ALRIs) worldwide. However, few spatial studies to date have reported on ALRI deaths. Purpose: We aimed to assess the spatial modeling of mortality from ALRI in children under 5 years of age during 2000-2017 using a global data. Methods: The data on the mortality of children under 5 years old caused by ALRI were initially obtained from the official website of the World Health Organization. The income status of their home countries was also gathered from the Country Income Groups (World Bank Classification) website and divided into 5 categories. After that, in the ArcGIS 10.6 environment, a database was created and the statistical tests and related maps were extracted. The Global Moran's I statistic, Getis-Ord Gi statistic, and geographically weighted regression were used for the analyses. In this study, higher z scores indicated the hot spots, while lower z scores indicated the cold spots. Results: In 2000-2017, child mortality showed a downward trend from 17.6 per 100,000 children to 8.1 and had a clustered pattern. Hot spots were concentrated in Asia in 2000 but shifted toward African countries by 2017. A cold spot that formed in Europe in 2007 showed an ascending trend by 2017. Based on the results of geographically weighted regression test, the regions identified as the hot spots of mortality from ALRI in children under 5 years old were among the middle-income countries (R²=0.01, adjusted R²=8.77). Conclusion: While the total number of child deaths in 2000-2017 has decreased, the number of hot spots has increased among countries. This study also concluded that, during the study period, Central and Western Africa countries became the main new hot spots of deaths from ALRI.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.189-196
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• 2009

We propose a hybrid broadcast scheduling based on a combination of periodic and on-demand data scheduling methods for mobile data broadcasting in convergence networks from communication and broadcasting. We consider an environment in which the forward channel is for data broadcasting and the reverse channel is for sending data requests via cellular phones, WLAN, WiBro, etc. Collecting statistics of requests from clients, the server partitions the data items into hot-item and cold-item sets. Hot items are sent based on a push-based scheduling. An on-demand scheduling method is applied to cold items. Performance evaluation from simulations shows that our proposed scheduling algorithm yields small response time with high successful response ratio.

• Korean Journal of Rural Living Science
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• v.10 no.2
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• pp.85-100
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• 1999

This study was to get basic data for the establishment of proper labor counterplan so that we estimated farm work volume and work loads by crops. We examined the method of work practices such as a work posture, work time, measured work environment such as hot, cold, humidity and ultraviolet rays and calculated physical loads induced by them. Also we surveyed work environment, work posture, sleeping time and work time because they affect on farmer's health. Farmer's health survey was investigated by questionnaire and measured farmer's physical load. The types of farm work were classified into greenhouse farming, rice farming, dry field farming, stock farming and special crop farming. 11 crops were selected, for example, greenhouse melon, riceㆍred pepper, milky cow farming, pear, grapes, dropwort, sweet potato, potato, radish, and cabbage. We also chose subject districts haying the most yield of 11 crops. Our survey was conducted for the period when farmers think the hardest period in physical work load. The farm work models based on work standard were presented according with farmer's health.

• Journal of Ecology and Environment
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• v.45 no.4
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• pp.277-286
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• 2021

Background: As trade increases, the influx of various alien species and their spread to new regions are prevalent and no longer a special problem. Anthropogenic activities and climate changes have made the distribution of alien species out of their native range common. As a result, alien species can be easily found anywhere, and they have nothing but only a few differences in intensity. The prevalent distribution of alien species adversely affects the ecosystem, and a strategic management plan must be established to control them effectively. To this end, hot spots and cold spots were analyzed according to the degree of distribution of invasive alien plants, and major environmental factors related to hot spots were found. We analyzed the 10,287 distribution points of 126 species of alien plants collected through the national survey of alien species by the hierarchical model of species communities (HMSC) framework. Results: The explanatory and fourfold cross-validation predictive power of the model were 0.91 and 0.75 as AUC values, respectively. The hot spots of invasive plants were found in the Seoul metropolitan area, Daegu metropolitan city, Chungcheongbuk-do Province, southwest shore, and Jeju island. Generally, the hot spots were found where the higher maximum temperature of summer, precipitation of winter, and road density are observed, but temperature seasonality, annual temperature range, precipitation of the summer, and distance to river and sea were negatively related to the hot spots. According to the model, the functional traits accounted for 55% of the variance explained by the environmental factors. The species with higher specific leaf areas were more found where temperature seasonality was low. Taller species preferred the bigger annual temperature range. The heavier seed mass was only preferred when the max temperature of summer exceeded 29 ℃. Conclusions: In this study, hot spots were places where 2.1 times more alien plants were distributed on average than non-hot spots (33.5 vs 15.7 species). The hot spots of invasive plants were expected to appear in less stressful climate conditions, such as low fluctuation of temperature and precipitation. Also, the disturbance by anthropogenic factors or water flow had positive influences on the hot spots. These results were consistent with the previous reports about the ruderal or competitive strategies of invasive plants instead of the stress-tolerant strategy. The functional traits are closely related to the ecological strategies of plants by shaping the response of species to various environmental filters, and our result confirmed this. Therefore, in order to effectively control alien plants, it is judged that the occurrence of disturbed sites in which alien plants can grow in large quantities is minimized, and the river management of waterfronts is required.