• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.57-66
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• 2016

In order to develop materials with a low environmental load for restoring the destroyed forest, seven types of wood-concrete hybrid laminated materials were manufactured with four softwoods, three hardwoods and concrete, and the effect of wood density on bending creep property was investigated. The bending creep curves showed a shape to considerably increase at the upper right side, and the curves were found to show a linear behavior beyond about 30 min - 1 hour, as behaviors of solid woods and wood-based materials. The initial compliances of wood-concrete hybrid-laminated materials decreased with an increase in the wood density, and those values showed 0.9 - 1.2 times of the concrete one. The creep compliances of hybrid laminated materials showed very low values, which were 0.4 - 0.8 times of the concrete ones. The relative creep were very low with a range from 8.2% to 17.0% range, which were 0.3 - 0.7 times of the concrete ones. These results indicate that these materials can be applied for restoring the destroyed forest to reduce creep deformation of the conventional concrete materials by hybrid-laminating concrete and woods.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.30-43
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• 2003

The geography, circulation pattern, and ecology show that the semi-closed seas of Northwest Pacific be managed as one complete system. Ongoing multilateral cooperative efforts relevant to marine environmental protection in the Northwest Pacific area, include the Working Group for the Western Pacific (WESTPAC) established under the auspices of WNESCO's Intergovernmental Oceanographic Commissions, the UNDP/GEF Programme on Prevention and Management of Marine Pollution in East Asian Seas (PEMSEA), the North Pacific Marine Science Organization(PICES), and the United Nations Environment Programme(WNEP)'s Northwest Pacific Action Plan(NOWPAP). The present report firstly describes the current situations on the existing regional cooperative regimes for marine environmental conservation in the Northwest Pacific region, with a special respect to the Northwest Pacific Action Plan(NOWPAP) which was adopted in 1994 by Japan, People's Republic of China, Republic of Korea and Russian Federation. Then, problems of the existing regimes are also discussed, together with the suggestion of the possible solutions, focusing on NOWPAP. Suggestions include: 1) the Northeast Asian countries should understand the importance of legally-binding regional convention, and should build up any legally-binding instrument which can function as a big umbrella for real regional cooperation without prejudice to the rights of the States, 2) At present stage, it will be possible to make a regional convention flexible without prejudice to the sovereign right of the States or territorial issues; 3) taking into account that the region often faces many generic political problems that often inhibit the effective collective actions on environmental issues, the leadership from UNEP or other international organizations is required; 4) strong institutional and financial framework should be made, and 5) multilateral efforts to respond to the new marine environmental threats should be taken at the regional level in order to protect the coastal and marine environments in the Northwest Pacific.

• Journal of the Korea Institute of Building Construction
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• v.21 no.3
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• pp.213-219
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• 2021

Change orders that occur frequently during the construction phase, af ect the construction performance in terms of cost, time, quality, safety and environment, and place a huge burden for stakeholders of given projects. This study analyzed the causes of change orders and their impact on the basis of 721 cases and a questionnaire of 164 domestic U.S. military construction participants in a total of 24 U.S. military projects. Important factors for change orders in the US military construction projects were engineering change due to design errors (348 cases, 48.3%), user requests change(86 cases, 11.9%), and different site conditions (69 cases, 9.6%). In addition, due to the change orders, construction cost increased by 6.56% on average and construction period was extended by 21.1% compared to the original schedule. As a result, it is anticipated that domestic construction companies can obtain a better understanding of change orders and construction performance, which may be difficult due to accessibility and limitations to military facilities. Also, it is proposed a successor study that guides in the right direction for the U.S. Military Construction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.1
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• pp.97-104
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• 2016

In Korea, the number of crash accident victims per 100,000 population is three times higher than the average of OECD. In particular, 60% of it occurs on the community road. Thus, this study intends to analyze the causes of such accidents through a pedestrian and vehicle traffic survey. The purpose is to establish practical safety enhancement measures for community roads. In recent years, lots of changes have occurred in the pedestrian environment. A traffic survey shows that 65% of pedestrians walk on the right and 17% of people use smart-phones while walking. An eye camera experiment shows that the operation load of drivers on the community roads is more than 4 times higher than those in urban roads. According to a speed survey, 62% of vehicles drive at 30km/h or above. The characteristics of accidents on community roads are as follows. First, the ratio of accidents on the edge of the road is 2.3 times as high as those on other roads. Second, when people walk on the right, the ratio of accidents is 2.5 times as high as that of walking on the left. Third, it becomes more dangerous when people cross the road from the right to the left. The majority of accidents is caused by unsafe driving (84.4%). When a vehicle makes a left turn, the likelihood of accidents is 2.3 times as high as those caused by a right turn. The ratio of accidents caused by vehicles going backwards is 14% among all accidents. In community roads, the focus of drivers should be at least 4 times higher than those on urban roads. Thus, walking in the opposite direction of vehicles and careless behaviors are highly likely lead to accidents.

• Hwankyungkyoyuk
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• v.21 no.4
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• pp.40-66
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• 2008

The purpose of this study is to develop and applicate textbook relevant to school indoor air quality. To achieve the purpose, concrete study process are as follows. First, the survey research to teachers, supervisors, and students is conducted to grasp cognition of subjects in elementary school and management situation about school indoor air quality. Second, contents relevant to indoor air quality on textbooks in the 7th elementary curriculum and subsidiary textbooks is analysed through reference study. Third, environmental textbook relevant to school indoor air quality for 5th and 6th grade in elementary school is developed, applicated, and inspected its effect on the basis of implications from results of survey and reference study. The results of this study are as follows. First, the result of survey concerning school indoor air quality showed that three groups had negative attitude for its management even though they thought that it affected human's health and study by and large. Student group thought that each of students itself was a little influence to school indoor air pollution though all of three groups answered that' activities of students' was its main source. Efforts of students to improve school indoor air quality was not much, and its main reason was that they didn't know about school indoor air pollution well. Second, result of analysis into textbooks on the 7th elementary curriculum and subsidiary textbooks, contents concerning indoor air on the 7th elementary curriculum textbooks was little or nothing. And it trended to be included to subsidiary textbooks. However, education textbooks about indoor air for elementary students was insufficient still. Third, environmental textbook relevant to school indoor air quality for 5th and 6th grade in elementary school was developed. It was constructed for themes - importance, sources, effects, and management of school indoor air quality. After its application to the 6th grade students in elementary school, it was meaningful in the level of p<.05 that the result of knowledge and awareness in the pre-post test within experiment group. However, all of the results in comparison group didn't represent statistically meaningful difference. In conclusion, environmental textbook developed by necessity of education about school indoor air quality will play a role as useful tool for the 5th, 6th grade students in elementary school to understand relation of quality of health and life and school indoor air quality, to have attitude to make an effort to manage it by develop right awareness about it.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.105-115
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• 1982

Environmental samples contaminated with elemental sulfur(waters 22, sediments 20, crucian carps 19) collected from Soho Lake during the period of Sep. 1981 to Apr. 1982 were analyzed for polychlorinated biphenyls(PCBs) and organochlorine insecticides by GLC-ECD. Elemental sulfur was found to interfere in the residue analysis of environmental samples and the sulfur was eliminated, prior to analysis, with copper powder. PCBs residues in Soho lake were temporarily characterized as Aroclor 1254 and were analyzed at minimum detectable quantity of 0.04 ng by derivatizing PCBs to decachlorobiphenyl(DCB). PCBs were positively detected in all samples and its residue levels in waters, sediments, and crucian carps were $0.015{\sim}0.15$ ppb, $0.038{\sim}0.088$ ppm and 0.091 ppm, respectively. The residue levels of PCBs in all samples but sediments at central and outlet site of the lake were higher than those of total p,p'-DDT. The residue levels of PCBs in waters varied with inlets, i.e. those at right inlet site were three times of those at left inlet site. The main source of PCBs residues in the environmental samples of Soho Lake was not evident by present work.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.210-217
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• 2003

An alternative method to the empirical approach such as Langmuir and Freundlich model, surface complexation model using thermodynamic database is used to simulate adsorption behavior of cadmium for oxide minerals. Sorption of cadmium onto amorphous silica ($SiO_2$) and synthetic goethite (${\alpha}$-FeOOH) at various conditions of pH, initial cadmium loading, oxide concentration, and ionic strength, were investigated. For both oxide minerals, increasing cadmium concentration resulted in right shifting of the sorption curve of cadmium as the function of pH. The $pH_{50}$, where 50% of cadmium sorbed, of goethite (pH 5.25) was much smaller than that of the silica (pH 7.83). The sorption of cadmium onto both minerals were not affected by the background ion strength from $10^{-1}$ to $10^{-2}$ M of $KNO_3$. It indicated that the binding affinity of goethite surface for cadmium is much stronger than that of silica. The strong affinity of oxide mineral for cadmium can be explained by the existence of coordination or covalent bond between cadmium and surface of it.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.3
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• pp.248-255
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• 2010

This study was carried out to assess the feasibility of the electron beam irradiation as a mean of red tide control in coastal water. Prorocentrum minimum, Prorocentrum micans, Cochlodinium polykrikoides, Heterosigma akashiwo, Alexnadrium catenella were selected and cultured for experiments, and red tide occurring in Tongyeong(2007. 8. 15) was also tested under the same conditions. The irradiation dose were 1 kGy, 2 kGy, 4 kGy and 8 kGy. The result showed 50~65% extinction in red tide cells was observed right after irradiation dose of 1 kGy and 86~97% within 1 day after irradiation, compared with control. Chlorophyll-a concentration of red tide was reduced by 50~64% immediately and it was drastically reduced up to 86~97% 1 day after irradiation. When the culture was irradiated at 1 kGy, 28~47% of s-protein was released immediately, and 77~138% was released 1day after irradiation. 77~212% of s-carbohydrate was excreted after 1 day while 16~45% of s-carbohydrate was excreted immediately. A transmission electron microscope(TEM) observation for the irradiated red tide revealed that the cell was destroyed and intracellular biopolymeric substance was leached out from the damaged cell as a result of electron beam irradiation. These results imply that electron beam irradiation is enable to control red tide by flocculation with extracellular biopolymer. The paralytic shellfish poisoning(PSP) toxin contents produced by Alexandrium catenella was decreased 48% by 1 kGy of electron beam irradiation compared with the unirradiated cells. As a result, electron beam irradiation was effective for detoxication as well as destruction of red tide.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.267-276
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• 2015

Several analyses on tritium that is the largest release of gas or liquid radioactive waste from domestic PWR and PHWR NPPs were carried out, such as release comparison, directional frequency of wind and tritium behavior changes in environmental samples. First of all, analysis result showed that tritium released from PHWR was more than ten times as gas and double to three times as liquid in comparison to PWR in 2013. Independent release management in NPP units is needed to precisely control and analyze tritium, since there were 2 units of some NPPs having the same amount of release during analysis. In analysis on frequency of wind direction, average range showed 1.7 to 11.5% by 16-point compass. In case of analysis on sampling points by wind direction, Result showed most of the sampling points are right in places. However, There are some areas needed to examine. In analysis on tritium concentration changes in environmental samples, tritium concentration near NPPs was higher than one far away from NPPs. In case of environmental samples far from PWR, a trace of tritium occur. While, tritium concentration near NPPs was more than or equal to one further from PHWR. In conclusion, tritium occurs considerably in PHWR and is lower than standard in samples. but, it is still detected. Therefore, it is needed to strengthen control in system in NPPs and to consistently monitor tritium in environment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3469-3476
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• 2015

The Korea Academia-Industrial cooperation Society. The Korea Academia-Industrial cooperation Society. In Korea, the territory has east high west low type and the rainfall is concentrated in the summer season. A nation having these topography and precipitation condition like Korea has to basically needs support of hardware alternatives. However, the right places decrease gradually and the resistance of the public opinion for national water resources policy stiffens gradually. The climate change has an effect in water resources fields and has a close relation. In the present study, therefore, future inflow of Miryang multipurpose dam basin is estimated by using SWAT model applied RCP 4.5 and 8.5 scenarios of "Korea Meteorological Administration" and considering the results, the future direction is purposed to operate the dam. As a result, the rainfall pattern is changed from traditional peak form to flat form. The dam operation rule in accordance with changing precipitation pattern has to be modified from the conventional operation rule and a new plan has to be established to meet a situation.