• Journal of dental hygiene science
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• v.13 no.1
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• pp.97-104
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• 2013

This study investigated the safety management behavior of dental professionals to minimize exposure to harmful elements of amalgam and resin. As for the use of amalgam and resin, 85.8% of them used amalgam. 100% of used composite resin 100%. 97.8% used acryl resin, and 95.7% used tray resin. 95.2% and 36.5% of them were aware of the harm of amalgam and resin respectively. When using resin, their safety management behavior score was 1.99 on average, and the lowest score was 2.50 on average for 'ventilate the indoor air when handling resin'. Their average score of the safety management behavior was 1.83 when using amalgam. The lowest score was 2.89 on average for 'use the rubber dam for patients when handling amalgam'. As a result of the safety management behavior based on general characteristics, all characteristics were significant with regard to amalgam, and my position at work and work experience were significant with regard to resin (p<0.05). The correlation between the safety management behavior and general characteristics was analyzed when dental amalgam and resin are used. Amalgam was statistically correlated with academic background (p<0.05) and position at work (p<0.05), whereas resin was statistically significantly correlated with age (p<0.05) and position at work (p<0.05). Accordingly, education about the harm of dental materials must be continuously provided for dental professionals when they handle dental materials so that safety management behavior will be conducted correctly, and active efforts to protect the health of dental professionals from harmful chemicals must be made.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.540-547
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• 1993

Backgrounds: The measurement of volume of isoflow has been considered as a sensitive test for detecting small airway diseases showing normal pulmonary function in a routine pulmonary function test. To evaluate the functions of small airway among dust exposed workers, the changes of volume of isoflow were measured and its applicability of managing early stage pneumoconiosis patients was studied. Method: The subjects were 67 male, pneumoconiosis with small opacity and FEV1>80%, FEV1/FVC>75% in spirometry and the controls were 20 male, no dust-exposed office workers. The maximal epiratory volume curves after inhalation of indoor air and $He-O_2$ gas mixtures were measured and ${\Delta}V_{max50},\;{\Delta}V_{max75},\;V_{iso}V/VC$ between the dust exposed and control workers were compaired. Results: 1) There were no significant differences between two group in ${\Delta}V_{max50}$ and ${\Delta}V_{max75}$. But the ratio of $V_{iso}V/VC$ of the subjects was siginificantly higher than that of the control (p<0.01). This study confirms that $V_{iso}V/VC$ is a very useful index in early detection of small airway dysfunction. 2) The ratio of $V_{iso}V/VC$ of the subjects was signigicantly different between only smoker group and mixed group(smoker and nonsmoker). It suggestes that smoking is an important cousative factor of small airway dysfunction. 3) As the profusion of the chest X-ray increased, the rartio of $V_{iso}V/VC$ increased, but no significant difference of $V_{iso}V/VC$ was found between categories of pneumoconiosis. The categories of pneumoconiosis and small airway dysfunction may not be related. 4) No significant relationship was established between the duration of work and the ratio of $V_{iso}V/VC$. Conclusions : It is concluded that the measurement of $V_{iso}V/VC$ is useful to detect small airway dysfuction of early stage pnuemoconiosis patents with small opacities but showing normal pulmonary function in a routine pulmonary function test.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.23-32
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• 2010

The purpose of this study is to quantify human energy budgets for different structures of outdoor spatial surfaces affecting thermal comfort, to analyze the impacts of tree shading on building energy savings, and to suggest desirable strategies of urban greenspace planning concerned. Concrete paving and grass spaces without tree shading and compacted-sand spaces with tree shading were selected to reflect archetypal compositional types for outdoor spatial materials. The study then estimated human energy budgets in static activity for the 3 space types. Major determinants of energy budgets were the presence of shading and also the albedo and temperature of base surfaces. The energy budgets for concrete paving and grass spaces without tree shading were $284\;W/m^2$ and $226\;W/m^2$, respectively, and these space types were considerably poor in thermal comfort. Therefore, it is desirable to construct outdoor resting spaces with evapotranspirational shade trees and natural materials for the base plane. Building energy savings from tree shading for the case of Daegu in the southern region were quantified using computer modeling programs and compared with a previous study for Chuncheon in the middle region. Shade trees planted to the west of a building were most effective for annual savings of heating and cooling energy. Plantings of shade trees in the south should be avoided, because they increased heating energy use with cooling energy savings low in both climate regions. A large shade tree in the west and east saved cooling energy by 1~2% across building types and regions. Based on previous studies and these results, some strategies including indicators for urban greenspace planning were suggested to improve thermal comfort of outdoor spaces and to save energy use in indoor spaces. These included thermal comfort in construction materials for outdoor spaces, building energy savings through shading, evapotranspiration and windspeed mitigation by greenspaces, and greenspace areas and volume for air-temperature reductions. In addition, this study explored the application of the strategies to greenspace-related regulations to ensure their effectiveness.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.179-190
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• 2012

This study was performed to obtain a heat saving effect and enhance the efficiency of a greenhouse by using a hot water piping in order to minimize the operating costs of a greenhouse as oil prices continue to rise. This method also reduces the likelihood of accidents caused by snowdrifts in regions with heavy snowfall. In general, the experimental plot was $2.0{\sim}6.0^{\circ}C$ higher than the control plot. When the skylight felt was opened, the minimum temperature was in the range of $3.0{\sim}12.0^{\circ}C$. Therefore, we judged that damage caused by snowdrifts may be prevented partly by active heating. The temperature difference inside of the greenhouse by height was insignificant. The maximum heating load of the greenhouse according to crop was respectively about $37,000kcal{\cdot}h^{-1}$ and $41,700kcal{\cdot}h^{-1}$. During the experiment, the heat value of each designed temperature in the range of the minimum ambient temperature $-11.9{\sim}4.0^{\circ}C$ was about 95,000~322,000 kcal and it was in the range of $6,050{\sim}20,900kcal{\cdot}h^{-1}$. If it is compared with the maximum heating load, it can be shown that about 15~56% of the heating energy can be supplied. The total heat value and the amount of power consumption were 2,629,025 kcal and 677.3 kWh respectively during the experiment. If it is heated with diesel, a fossil fuel, the consumption during the experiment was 291 L and the cost was 331,700won. Total cost of using electric power was about 24,400 won and it is shown that it is about 7.5% of the cost of diesel consumption. Also, if the total amount of power consumption is converted into energy, it is approximately 582,200 kcal and the energy was just about 22% of the total heat value.

• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.472-480
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• 2019

Selection of the plant material for planting to reduce fine dust should comprehensively consider the visual characteristics, such as the shape and texture of the plant leaves and form of bark, which affect the adsorption function of the plant. However, previous studies on reduction of fine dust through plants have focused on the absorption function rather than the adsorption function of plants and on foliage plants, which are indoor plants, rather than the outdoor plants. In particular, the criterion for selection of fine dust reduction species is not specific, so research on the selection criteria for plant materials for fine dust reduction in urban areas is needed. The purpose of this study is to identify the priorities of eight indicators that affect the fine dust reduction by using the fuzzy multi-criteria decision-making model (MCDM) and establish the tree selection criteria for the urban planting to reduce fine dust. For the purpose, we conducted a questionnaire survey of those who majored in fine dust-related academic fields and those with experience of researching fine dust. A result of the survey showed that the area of leaf and the tree species received the highest score as the factors that affect the fine dust reduction. They were followed by the surface roughness of leaves, tree height, growth rate, complexity of leaves, edge shape of leaves, and bark feature in that order. When selecting the species that have leaves with the coarse surface, it is better to select the trees with wooly, glossy, and waxy layers on the leaves. When considering the shape of the leaves, it is better to select the two-type or three-type leaves and palm-shaped leaves than the single-type leaves and to select the serrated leaves than the smooth edged leaves to increase the surface area for adsorbing fine dust in the air on the surface of the leaves. When considering the characteristics of the bark, it is better to select trees that have cork layers or show or are likely to show the bark loosening or cracks than to select those with lenticel or patterned barks. This study is significant in that it presents the priorities of the selection criteria of plant material based on the visual characteristics that affect the adsorption of fine dust for the planning of planting to reduce fine dust in the urban area. The results of this study can be used as basic data for the selection of trees for plantation planning in the urban area.

• 지역과문화
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• v.6 no.3
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• pp.79-105
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• 2019

In the Geumseongsan Tumulus of the Uiseong area where the Jomunguk was existed in the Three Han Period, many relics such as metal craft ornaments and Uiseong-style earthernware were excavated. However, it is hard to find cases where the excavated relics were used to develop cultural products. In this study, symbolic relics which can express the culture of Uiseong Jomunguk were selected from excavated relics. Then, the basic design that can be applied to various cultural products were derived from symbolic relics. In order to select symbolic relics, the formative characteristics of the metal craft relics excavated from the Tablili Tumulus and the Dali Tumulus were examined. As a result, a gilt-bronze crown excavated from the Tablili Tumulus was selected as a symbolic relics. And then the basic desin was derived from the gilt-bronze crown. The basic design is expressed in the form of birds based on the bird's feather shape at the edge of the standing ornaments and the record of the Bongdae(鳳臺), the phoenix's habitat. And the application design that changed the expression of the birds' face was presented. The earthenware excavated from the Uiseong area was designed as a soil pot and applied various indoor air purification plants. The result of this study, which reinterprets and reconstructs the historical and cultural resources of the region in accordance with the modern sense, can be used as useful data for the development of cultural products of Jomunguk. Furthermore, if the design derived from the Jomunguk relics is used as a representative symbol of the area, it will be possible to derive an image of a differentiated region from other regions. Finally, it is expected that the result of this study will be a chance to re-evaluate the value of the historical and cultural resources in the region.