• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.250-256
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• 2013

Gasoline generates organic acid and polymer (gum) by hydrocarbon oxidation depending on the storage environment such as temperature and exposure to sunlight, which can cause metal corrosion, rubber and resin degradation and vehicle malfunction caused by accumulation in fuel supply system. The gasoline which has not been used for a long time in bi-fuel (LPG-Gasoline) vehicle causes problems, and low octane number gasoline have evaporated into the field, but the exact cause has not been studied yet. In this study, we suggest a plan of quality management by investigating the gasoline oxidation behavior. In order to investigate the oxidation behavior of gasoline, changes of gasoline properties were analyzed at various storage conditions such as storage time, storage vessel type (vehicle fuel tank, PE vessel and Fe vessel) and storage circumstances (sunlight exposure and open system, etc.). Currently distributing gasoline and bioethanol blended fuel (blended 10%) were stored for 18 weeks in summer season. The sample stored in PE vessel was out of quality standard (octane number, vapor pressure, etc.) due to the evaporation of the high octane number and low boiling point components through the vessel cap and surface. Especially, the sunlight exposure sample stored in PE vessel showed rapid decrease of vapor pressure and increase of gum. Bioethanol blended fuel showed similar results as gasoline.

• Korean Journal of Community Nutrition
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• v.20 no.3
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• pp.197-207
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• 2015

Objectives: This study was conducted to investigate the effects of the sources of vitamin D (duration of exposure to sunlight, intake of major food sources for vitamin D or vitamin D supplements) on the serum 25-(OH) $D_3$ levels, and the physical growth of a child. Methods: Subjects were 296 children aged 1 to 5 years who visited S hospital located in Changwon City. Survey data collection was carried out by direct interview method, and the biochemical data were collected using hospital records. Results: The study subjects were divided into three groups according to their levels of serum 25-(OH) $D_3$ (deficient, relatively insufficient, sufficient) and their percentage were 48.3%, 44.3% and 7.4% respectively. The average concentration of serum 25-(OH) $D_3$ was $20.41{\pm}6.55ng/mL$, which was relatively insufficient. The average duration of exposure to sunlight was $58.86{\pm}49.18minutes/day$. A total score of vitamin D major food sources was 46.71 points (full marks 153), and the most frequently consumed food items were milk, eggs, and cheese. Thirty-four percent of the subjects took vitamin D supplements and their dose were $11.96{\mu}g/day$. Three vitamin D sources in sufficient group were higher than deficient or relatively insufficient group significantly. Intake of vitamin D supplements showed positive relation (+) and high explanation power ($R^2=0.288$) on serum 25-(OH) $D_3$ concentration, but intake of vitamin D major food sources (+) and the duration of exposure to sunlight (+) had a low explanation power ($R^2=0.068$). The relations between serum 25-(OH) $D_3$ concentration and physical growth (height and weight) were shown as negative (-), and their explanation powers were low as 7.3% and 5.9% respectively. Conclusions: This study results can be useful when discussing the intake standard of vitamin D and the effective intake method for children. In addition, it will be helpful to build the children's nutrition policy and to plan the nutrition education program to improve the vitamin D status in children.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.751-759
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• 2014

Currently, due to global warming, occurrences of extreme climate phenomena such as heat wave, heavy snow, heavy rain, super typhoon are continuously increasing all over the world. Due to these extreme climate phenomena, concrete structures and infrastructures are exposed to serious deterioration and damage. However, researches on construction technologies and standards to confront the climate change generated problems are needed presently. In order to better handle these problems, the validity of the present concrete mixture proportions are evaluated considering wind speed and sunlight exposure time based on climate change record in Seoul, Korea. The specimens cured at various wind speed and sunlight exposure time conditions were tested to obtain their compressive and split tensile strengths at various curing ages. Moreover, performance based evaluation (PBE) method was used to analyze the target strength satisfaction percentage of the concrete cured for the curing conditions. From the probabilistic method of performance evaluation of concrete performance, feasibility and usability of current concrete mix design practice for climate change conditions can be evaluated.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.75-83
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• 2000

Recently, many landfills are constructed by using geosynthetics with earth materials. Geotextiles in geosynthetics are applied for the various purposes such as filters of the leachate collection and removal system and protectors of geomembrane liner. However geotextiles can be exposed to direct sunlight during the construction of landfill for several months. As you know the exposure of polymers to sunlight can be a major source of degradation of them. This study is to suggest a criteria on the installation of heavy weight geotextiles at the landfill. For this purpose, several different geotextiles were evaluated by outdoor exposure at two different locations and under the different seasons for one and half years. As the results of outdoor exposure, polypropylene geotextiles with 500g/$m^2$ and 700g/$\textrm{m}^2$were maintained around 40% of the initial strength during for one and half years. However, the polypropylene geotextile of 1000g/$\textrm{m}^2$showed 65% of the retained strength for the same duration of exposure. The retained strength of all polypropylene geotextile reduced dramatically with the cumulative sunshine radiation on a horizontal surface of around 1500MJ/$\textrm{m}^2$.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.194-195
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• 2011

• Korea Journal of Cosmetic Science
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• v.2 no.1
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• pp.1-10
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• 2020

Protection mechanisms for skin damage of ultraviolet (UV) absorbers in personal care products for protection against UV are well studied, but not for hair protection. The purpose of this study is to describe and compare the changes of physical property produced in human hair by doses of the UV-B exposure causing protein degradation. To observe the change of physical properties in hair, the experimental intensity of UV-B exposure has been established on the basis of statistical data from official meterological administration as daily one hour sunlight exposure for two weeks. Polysilicone-15, ethylhexyl methoxycinnamate (OMC), and octocrylene were employed for UV-B absorber, and those were treated to hair swatch by rubbing wash through shampoo and conditioner. Bending rigidity displayed kinetically successive reduction at high doses of UV exposure up to the 8,000 s, and exhibited different level at each sample of UV-B absorber. However, the values of Bossa Nova Technologies (BNT) for shinning factor were already saturable at the 2,000 s exposure except that treated with polysilicone-15. The differential scanning calorimetry (DSC) to measure a strength of inner protein produces a successive reduction of enthalpy as like a reduction of bending rigidity upon UV exposure. Surface roughness from lateral force microscope (LFM) acquired immediately after UV exposure show a saturable frictional voltage which has been also found in a saturable BNT data as the time of UV exposure increases. Through researching the DSC and the LFM, shinning of hair was much correlated to the protein damage at the surface, and bending rigidity could be regulated by the protein structural damage inside hair. Therefore, the optimization of efficient strategy for simultaneous prevention of hair protein on the surface and internal hair was required to maintain physical properties against UV.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.5 s.108
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• pp.36-43
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• 2004

The behaviors of deterioration in the mechanical and optical properties of paper during sunlight exposure are mainly attributed to UV irradiation. The effect of different additives (anti-UV agents) on paper properties during exposure was studied. The results showed negligible changes in the mechanical properties of samples prepared with two different ways, whereas the shielding ability was increased when the additives were applied to the surface of hand sheets. Also, the paper which is treated with anti UV agents can keep freshness more effectively of agricultural products from UV irradiation.

• The Research Journal of the Costume Culture
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• v.20 no.4
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• pp.463-474
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• 2012

The purpose of this research was to find the suitable dyeing method for dyeing cotton fabric into indigo blue color using the raw indigo powder dyes sold in the Korean market. The research focused primarily on the comparison of the non-reduced dyeing method and the reduced dyeing method. The dyeing effects using different dyeing temperatures ($2{\sim}80^{\circ}C$) and different concentrations of reducing agent and alkali were also investigated. It was found that the reduced dyeing method must be used for dyeing cotton into indigo blue color using the commercial raw indigo powder dyes. The best result was obtained by $20^{\circ}C$ dyeing with the $40^{\circ}C$ dyeing giving a comparable result. The intensity of the blue color could be enhanced by increasing the alkali concentration. The non-reduced dyeing could not dye cotton fabric into indigo blue color at any given dyeing temperatures ($2{\sim}80^{\circ}C$). The reduce-dyed cotton fabrics showed a gradual color change upon repeated washing and extended sunlight exposure, the most color change occurring after the first two washing cycles and the first 5 hours of sunlight exposure. The standard tests of colorfastness showed that the reduce-dyed cotton fabrics had good to excellent colorfastness whereas the colorfastness of the non-reduce-dyed cotton fabrics were mostly poor.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.601-609
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• 2016

Recently, extreme climate change has been occurring globally not only in the simple form of temperature increases but also in a wide range of extreme climatic events, such as abnormal drought conditions and frequent typhoons. In addition, climate change is delaying the construction period of concrete structures, increasing related economic losses. Forcing construction projects for completion without considering climate change is leading to concrete quality deterioration, poor quality constructions, and consequent casualties and property damage. Therefore, to address these problems and provide a countermeasure to climate change, the present study selected wind speed, and sunlight exposure time as the most important curing conditions among the climate factors affecting concrete structures and examined their effects on the curing and durability of concrete structures. In addition, for the analysis of the experimental results, this study proposed a process of performance based evaluation (PBE) of concrete strength and durability using a method of Satisfaction Curve (SC) generation.

• KIEAE Journal
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• v.13 no.5
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• pp.59-66
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• 2013

Current Architectural Facade Designs have been trending to increased glass areas resulting in increasing impact on interior lighting and daylighting. In regards to indoor environmental quality, the increase in window space has a large impact on the daylighting received which ultimately impacts the liveability of a space. Especially when considering seasons, in the summer, excessive daylighting can result in glare as well as put an increased load in conditioning the air space further reducing energy efficiency. As a result, in order to improve the sustainability performance of a building, it is important to limit the natural lighting exposure to properly meet the needs and conditions of the building occupants. One of the most representative features to limit excessive sunlight exposure, is to incorporate operable blind systems. To this end, this research has been based on simulations performance through the Radiance Program. Radiance is capable of analyzing performance of daylight and impact of sunlight. Through analysis of different slat angles and blind shapes, impact and minimization of energy usage was evaluated. Furthermore, seasonal analysis was performed in order to understand the effects of seasonal climate factors. Ultimately this research provides an analysis of operable blinds optimization and effects of blind shape, control factors and angle of shading.