• 한국지반환경공학회 논문집
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• 제7권6호
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• pp.113-119
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• 2006

최근 건설현장에서 물유리계 공법의 현장적용 시 고결체의 결과물은 내구성, 강도, 용탈에 대한 평가에 있어서 차수목적으로는 적용이 가능하나 영구적인 지반보강 및 차수를 위한 공법으로는 그 한계성이 지적되는 바, 시멘트계 급결재와 무기질계 초미립자를 주원료로 하는 순수 무기질 재료를 사용하여 시공한 후 내구성 및 강도가 우수하고 주입성이 탁월한 동시에 주입재의 용탈현상이 발생하지 않아 친환경적이고 영구적인 차수 및 보강에 적합한 환경 친화적 공법에 대한 연구를 수행하게 되었다. 본 연구는 지반보강 목적으로 무기질계 지반주입공법(NDS)을 적용할 경우에 사용되는 무기질계 고성능 지반안정재에 대하여 일축압축강도시험, 투수시험, 길이변화시험, 용탈시험, 환경유해성시험을 통해 물유리계 재료와 비교하여 NDS공법의 강도 특성과 친환경성을 규명하고자 하였다. 그 결과 강도 및 투수성이 향상되었고 길이변화율은 담수에서는 494,186배, 해수에서는 61,927배로 크게 개선되었으며, 용탈되는 원소의 총량도 극히 작았다. 또한 환경유해성평가 결과 Zn을 제외한 중금속 성분이 검출되지 않아 친환경적인 재료임을 입증하였다.

• 한국지반환경공학회 논문집
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• 제16권5호
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• pp.5-11
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• 2015

지하수 내에 영양염류와 중금속 등의 오염물질이 동시에 존재하는 경우 두 가지 이상의 반응성 매질을 적용한 연속식 반응벽체공법이 적용될 수 있다. 본 연구에서는 영양염류 오염물질인 암모늄과 인산염, 그리고 중금속인 카드뮴의 복합오염물질의 제거를 위해 제올라이트와 제강슬래그를 반응성 매질로 구성한 연속식 반응벽체공법의 적용성을 평가하였다. 흐름 조건을 모사한 주상실험을 수행하여 제올라이트와 제강슬래그와의 연속반응에 의한 오염물질의 제거효과를 평가하였다. 주상실험결과는 비평형 이류확산 모델을 적용하여 주상실험에서의 비평형 반응을 해석하였다. 주상실험을 통해 제올라이트는 암모늄 제거에 효과적이며 제강슬래그는 인산염과 카드뮴 제거에 효과적임을 확인하였으며, 연속식 반응벽체 구성 시 제올라이트와 제강슬래그 순서로 반응시키는 조건이 효과적인 것으로 나타났다.

• Journal of Korean Biological Nursing Science
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• 제13권2호
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• pp.109-116
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• 2011

Purpose: The purpose of this study was to exam the effects of nursing information about intensive care unit environment on ICU patient's environmental stress, anxiety and comfort. Methods: A non-equivalent control group with non-synchronized quasi-experimental research design was used. Participants were 60 (control 30, experimental 30) patients who admitted at ICU in one hospital in Gangneung. Experimental group was provided with nursing information about intensive care unit environment. To avoid contamination of the experiment, data for the control group were collected prior to the experimental group. Paired t-test, t-test, chi-square test were used to analyze the data using the SPSS WIN 19.0 Program. Results: ICU environmental stress (t=-.089, p=.045) and anxiety (t=-5.65, p<.001) were significantly more reduced than before intervention. Also, comfort (t=-2.98, p=.036) was significantly more improved than before intervention. Conclusion: It confirmed that nursing information on ICU environment is effective in reducing environmental stress, anxiety and improving comfort in ICU patients.

• 환경위생공학
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• 제17권3호
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• pp.21-30
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• 2002

This study was Performed to evaluate the effective solidification of Cd sludge using cement and power plant fly ash as cement admixture, to identify the leaching characteristics of the heavy metal Cd sludge solidified, and to develope proper KLT(Korean Leaching Test) of hazardous waste. KLT was compared with EPT(Extraction Procedure Toxicity) and TCLP(Toxicity Characteristics Leaching Procedure). Fly ash contents ranged from 0% to 30% of cement weight. The experimental results showed that the optimum amount of fly ash replaced was 10% to 15% and KLT was less appropriate than EPA and TCLP. Also the purpose of the study was to suggest the modification factors on the leaching test currently used, based on the above mentioned aspects. The effects of pH, leaching time, leaching for agitating intensity, and leaching solvent were investigated. As the result of test, the leaching potential was relatively high when the pH and agitation intensity of leaching solution were 5 and 150rpm, respectively. Leaching time of six hours was found to be sufficient and the use of acetic acid as a leaching solvent is more useful in landfill site particularly.

• 대한가정학회지
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• 제42권9호
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• pp.111-134
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• 2004

The purpose of this dissertation is firstly to examine the level of pro-environmental behavior of urban employed wives depending on their life style type and secondly to identify effective ways to promote their pro-environmental behavior. A structured questionnaire interview was conducted with 700 urban employed wives who lived in the Seoul Metropolitan area, and 566 of the responses were valid for analysis. For statistical analysis, this research reviewed the frequencies, percentage, mean, standard deviation(SD), Pearson's correlations, Cronbach's u, factor analysis, cluster analysis, ANOVA, $\chi$$^2$-test, Duncan's Multiple Range Test, and multiple regression using SPSS/PC WIN. The findings of analysis of the study are as follows: 1. Among life style types of employed wives, the order of ecological value was orientation type (37.3%), followed by economical value orientation type (25.8%), uninterested type (18.7%), and convenience-centric value orientation type (18.2%).Pro-environmental behavior scored relatively highly at 3.45 in average. 2. In the analysis of the relationship between life style and background variations, every variation except environmental knowledge was meaningful. 3. In the relationship between pro-environment behavior and background variations, every variation was meaningful except housing types, having helper or not, and environmental knowledge. 4. The recognition level of environmental pollution was important among the variations affecting pro-environmental behavior. 5. There was a difference in pro-environmental behaviors by the following life style types: ecological value orientation, economical value orientation, convenience centric orientation and uninterested. 6. For the relative contribution comparison of background variations (socio-economic variation and environmental variation) and life style variations to the pro-environmental behavior of urban empolyed wives, this research additionally applied each independent variable group. As a result, the explanation level drastically increased in the third step that analyzed the relationship with life style.

• Geomechanics and Engineering
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• 제5권3호
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• pp.195-221
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• 2013

A centrifuge model study is carried out to investigate the behavior of pile subject to negative skin friction induced by pile installation, ground water drawdown and surcharge loading. A single end-bearing pile is examined as the induced negative skin friction would induce the most severe stress on the pile structural material as compared to friction piles. In addition, the behavior of the pile under simultaneous negative skin friction and dead/live loads is examined. To facilitate detailed interpretations of the test results, the model setup is extensively instrumented and involves elaborate test control schemes. To further examine the phenomenon of negative skin friction on an end-bearing pile, finite element analyses were conducted. The numerical analysis is first validated against the centrifuge test data and subsequently extended to examine the effects of pile slenderness ratio, surcharge intensity and pile-soil stiffness ratio on the degree of mobilization of negative skin friction induced on the pile. Finally experimental and numerical studies are conducted to examine the effect of applied transient live load on pile subject to negative skin friction.

• 한국해양공학회지
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• 제20권2호
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• pp.52-58
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• 2006

The effect of various environmental conditions on the durability of E-glass fiber/vinylester resin composites have been investigated using the tensile test specimen of strand type. It was found that the durability test method performed by the stand type specimen was more convenient and reliable than other conventional test method. The weight gains increased with the immersion time in both water and alkaline solution, and the Weight gains at $50^{\circ}C$. were much bigger than those at $20^{\circ}C$ in both conditions. The tensile strength decreased with the pass of immersion time in all aqueous solution, and the tensile strength at $80^{\circ}C$ in alkaline solution decreased very steeply at beginning of immersion time. The decrement of tensile strength according to the immersion time in various environmental conditions was mainly caused by the degradation of interface and the damage of glass fiber surface.

• Steel and Composite Structures
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• 제31권1호
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• pp.53-67
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• 2019

This study presents finite element analysis (FEA) on a Y-type perfobond rib shear connection using Abaqus software. The performance of a shear connection is evaluated by conducting a push-out test. However, in practice, it is inefficient to verify the performance by conducting a push-out test with regard to all design variables pertaining to a shear connector. To overcome this problem, FEA is conducted on various shear connectors to accurately estimate the shear strength of the Y-type perfobond rib shear connection. Previous push-out test results for 14 typical push-out test specimens and those obtained through FEA are compared to analyze the shear behavior including consideration of the design variables. The results show that the developed finite element model successfully reflects the effects of changes in the design variables. In addition, using the developed FEA model, the shear resistance of a stubby Y-type perfobond rib shear connector is evaluated based on the concrete strength and transverse rebar size variables. Then, the existing shear resistance formula is upgraded based on the FEA results.

• 한국환경농학회지
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• 제21권3호
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• pp.172-177
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• 2002

살충제 carbofuran의 수중 광분해 실험을 미국 EPA 및 OECD 방법으로 수행하였다. Carbofuran은 자연광을 흡수하지 않는 화합물이지만, 야외에서 증류수로 수행한 광분해시험 결과 반감기가 9.7일, SUNTEST에서 3.4일, SUNTEST의 UV하에서 1시간으로 신속한 광분해가 일어남을 확인하였다. 특히 논물에서는 SUNTEST에서의 반감기가 14시간으로 증류수 보다 약 6배 가속화되었으며, 살균한 논물보다는 비살균 논물에서의 광분해가 다소 빠르게 일어났다. 이와 같은 결과로 볼 때 carbofuran의 경우 수도작 상황에서 sensitizer 등에 의한 간접 광분해의 가능성이 있음을 확인하였다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.325-332
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• 2000

The objective of this research work is to develop an autonomous levee-weeding robot. In this paper, pathway control system for the robot is developed and simulated. A prototype autonomous vehicle for levee weeding is also developed and used in the actual test. The results obtained in this research work is summarized as follows; 1) The simulated typical time history of lateral displacements and heading angle of the vehicle in straight run shows that the vehicle tendency is always to achieve the target path from any of its deviated position and heading angle. 2) The test run on an asphalt surface by the prototype crawler-type vehicle is in good agreement with the simulation results.