• 한국컴퓨터정보학회논문지
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• 제7권4호
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• pp.220-234
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• 2002

This study examined the impact of preventive environmental management practices on sales growth, manufacturing and environmental performance of the US chemical manufacturing companies. In order to investigate the impact, this study examined the relationship between the degree of preventive environmental programs and sales growth, manufacturing and environmental performances. Using a cross-sectional research design to test three hypotheses. a survey questionnaire was mailed to chemical companies in the USA. To investigate the relationship between the degree of Preventive environmental programs and sales growth, manufacturing and environmental performances. t-tests were used. According to the results of t-tests the higher preventive implementation programs achieved better manufacturing and environmental performances than lower preventive or reactive strategies. But there was no difference in sales growth between tow groups.

• 한국환경보건학회지
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• 제37권1호
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• pp.57-63
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• 2011

Crocidolite quality control (QC) sampling created by the wet generation method has been validated by validation tests such as the accuracy, precision, and storage tests. For this study we designed and developed a manufacturing apparatus and standard operating procedure for making these QC samples. The most important step in the procedure of making QC samples was the stage eliminating static electricity in asbestos fibers. This static electricity hampers the fibers clog functioning. In accuracy and precision tests by phase contrast microscopy analysis, the difference between the reference values and the studied values was at maximum 17.8%. This satisfies the AIHA proficiency analytical test criteria for asbestos. We could confirm the nearly even distribution of crocidolite fibers on the membrane filter. Also, there was no loss of fibers in the storage test after the one month.

• Environmental Engineering Research
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• 제11권3호
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• pp.156-163
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• 2006

In this study, substrate removal characteristics were analyzed to reduce the cost of external carbon dosage at Sudokwon Landfill Site Management Corporation in Korea by utilizing oxygen uptake rate (OUR) and nitrate uptake rate (NUR) tests. To estimate and evaluate the substrate removal characteristics obtained by the batch tests, the lab-scale MLE process was operated. By-products of J Co. (sugar manufactory) and S Co. (fine chemical industry) were selected as the concerned carbon sources through a comparison of carbon and nitrogen contents. MeOH was tested as a control experiment. Until the steady state, the fraction of $RBDCOD_{OUR}$ concentration to COD concentration of J Co., S Co. by-products and MeOH increased and reached levels of 98%, 82%, and 100%, respectively. During the 20th operating day, the fraction of $RBDCOD_{NUR}$ concentration to COD concentration was 95%, 81%, and 83%, respectively. These fractions of $RBDCOD_{NUR}$ concentration to $RBDCOD_{OUR}$ concentration increased according to acclimation periods and reached levels of 99%, 97%, and 81%, respectively, on the 20th day. The results obtained from the lab-scale MLE process operation using the concerned carbon sources as external carbon were similar to that observed by OUR and NUR tests.

• Steel and Composite Structures
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• 제43권4호
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• pp.431-445
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• 2022

A double-skinned composite tubular (DSCT) column, which is an internally confined concrete-filled tubular column with a hollow section, has been developed for efficient use of materials that reduce self-weight and enhance seismic performance. It exhibits excellent material behavior with ductility owing to the confinement induced by outer and inner steel tubes. This study conducted axial compression tests considering the effects of steel tube thickness and hollow diameter ratios of DSCT columns on the material behavior of confined concrete under pure axial compression on concrete cores. From the axial compression tests, various combinations of outer and inner tube thicknesses and two different hollow section ratios were considered. Additionally, confined concrete material behavior, axial strength, failure modes, and ductility of DSCT columns were evaluated. Based on this study, it was concluded that the tests show a good correlation with peak strength and shapes of nonlinear stress-strain curves presented in literature; however, the thinner outer and inner steel tubes may reduce the ductility of DSCT columns when using thinner outer and inner tubes and higher confined stress levels. Finally, the minimum thickness requirements of the steel tubes for DSCT columns were discussed in terms of strength and ductility of test specimens.

• Environmental Analysis Health and Toxicology
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• 제2권1_2호
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• pp.1-12
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• 1987

• 한국항해항만학회지
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• 제33권2호
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• pp.119-125
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• 2009

The effect of plastic board drains (PBDs)on ground improvement was checked out considering three crucial factors: ground settlement, undrained shear strength, and residual water head. First, the settlement analysis including initial settlement induced by reclamation of sand mat was conducted by back calculation analysis with measured data. Its result showed toot the PBDs used for this site worked well on improving soft ground. Secondly, the undrained shear strength was investigated by laboratory and in-situ tests including unconsolidated-undrained triaxial compression (UU) tests, unconfined compression tests, in-situ vane tests, and cone penetration tests. From the test results, they showed that the undrained shear strength of the improved ground by PBDs was significantly increased as well as the strength increasing ratio especially $10{\sim}15m$ below the ground surface on site. Thirdly, the residual water head measurement from the in situ dissipation test was found the same as the static water head, which indicated primary consolidation was completed and the effect of soil improvement with PBDs can be confirmed.

• Wind and Structures
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• 제15권6호
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• pp.495-508
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• 2012

The present paper is focused on the prediction of the acrosswind aeroelastic response of square tall buildings. In particular, a semi-analytical procedure is proposed based on the assumption that square tall buildings, for reduced velocities corresponding to operational conditions, do not experience vortex shedding resonance or galloping and fall in the range of positive aerodynamic damping. Under these conditions, aeroelastic wind tunnel tests can be unnecessary and the response can be correctly evaluated using wind tunnel tests on rigid models and analytical modeling of the aerodynamic damping. The proposed procedure consists of two phases. First, simultaneous measurements of the pressure time histories are carried out in the wind tunnel on rigid models, in order to obtain the aerodynamic forces. Then, aeroelastic forces are analytically evaluated and the structural response is computed through direct integration of the equations of motion considering the contribution of both the aerodynamic and aeroelastic forces. The procedure, which gives a conservative estimate of the aeroelastic response, has the advantage that aeroelastic tests are avoided, at least in the preliminary design phase.

• 한국전문물리치료학회지
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• 제24권3호
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• pp.1-9
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• 2017

Background: The method of measuring the walking function of patients with chronic stroke differs depending on patients walking capability and environmental conditions. Objects: This study aimed to demonstrate the influences of walking capacity and environmental conditions on the results of short- and long-distance walk tests in patients with chronic stroke. Methods: Forty patients with chronic stroke volunteered for this study, and allocated to group-1 (<.4m/s, household walking, $n_1=13$), group-2 (.4~.8m/s, limited community ambulation, $n_2=16$), and group-3 (>.8m/s, community ambulation, $n_3=11$) according to their walking capacity. The 10-meter walk test (10MWT) and 6-min walk tests, (6MWT) were used to compare the short- and long-distance walk tests results, which were randomly performed under indoor and outdoor environmental conditions. Results: The comparison of the results obtained under the indoor and outdoor conditions revealed statistically significant differences between the groups in the 6MWT and 10MWT (p<.05). Post-hoc tests' results showed significant differences between groups-1 and -2 and between groups-1 and -3 in the 10MWT, and between group-1 and -3 in the 6MWT. Furthermore, in group-2 the 10MWT and 6MWT results significantly differed between the indoor and outdoor conditions, and the values measured under the indoor and outdoor conditions significantly differed between 10MWT and 6MWT (p<.05). Group-3 showed a significant difference in 10MWT results between the indoor and outdoor conditions (p<.05). Conclusion: These findings suggest that the results of the short- and long-distance walk tests may differ depending on the walking capacity of patients with chronic stroke and the environmental condition under which the measurement is made, and these effects were greatest for the patients with the limited community ambulation capacity.

• 한국지반환경공학회 논문집
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• 제14권1호
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• pp.61-68
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• 2013

본 연구에서는 지반보강재로서 폐타이어 사용에 따른 환경영향을 평가하기 위하여 실내실험 및 현장시험시공을 수행하였다. 실내실험을 통하여 폐타이어의 용출특성에 가장 큰 영향을 미치는 폐타이어의 입경과 배수조건을 변화시켜가며 유출수의 pH, 탁도, TOC, Zn 농도를 분석하였다. 또한, 현장시험시공을 통하여 폐타이어를 이용한 보강토 옹벽 시공 후 하부 집수정의 수질을 분석하였다. 입경에 따른 용출실험 결과 폐타이어 입경이 증가할수록 용출농도가 감소하는 것을 확인할 수 있었으며, 이는 비표면적의 차이 때문으로 판단된다. 배수조건에 따른 용출실험 결과 배수조건인 경우 시간이 경과할수록 용출농도가 감소하여 주변 환경에 큰 영향을 미치지 않을 것으로 판단되나, 비배수 조건인 경우 시간이 경과할수록 용출농도가 증가하는 현상을 발견할 수 있었다. 1년간의 현장모니터링 결과 폐타이어로 보강된 옹벽으로부터 발생되는 침출수는 전반적으로 용출농도가 높지 않은 것으로 나타났으며, 침출수 발생 초기에 농도가 증가하다가 이후 점점 감소하여 원수인 우수와 비슷해지는 경향을 나타내었다. 따라서 폐타이어를 지반보강재로 사용함에 따라 발생하는 환경적 영향은 무시할 수 있는 수준임을 알 수 있었다.

• 한국환경독성학회:학술대회논문집
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• 한국환경독성학회 2001년도 춘계심포지움 및 학술발표회
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• pp.128-128
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• 2001

Atrazine, one of herbicide widely used in agriculture, is classified as a possible human carcinogen (2B group) that may cause breast and ovarian cancers by IARC, and is known as an endocrine disrupter. Atrazine has been subjected to broad ranges of genotoxicity tests wi th predominantly negative results, but reported conflicting results across two or more independent tests as well. (omitted)