This study investigated the impact resistance properties of UHPC and HDFRC. Test results showed that the HDFRC mixture has a higher penetration depth than the UHPC mixture, however, the HDFRC mixture has a higher impact resistance performance without perforation based on high ductility through multiple micro cracks.

This study investigated the damping properties of preplaced concrete with W/C and coarse aggregate size was . Experimental results show that the damping ratio of the C40 is 2.63%, which is 1.72 times higher than the damping ratio of the C30 of 1.53%. The higher the water cement ratio, the higher the damping ratio is. In addition, the damping ratio of the C-PA series is reduced by 17% to 60% as compared with the C-series. The difference of the damping ratio due to the coarse aggregate size in the C-PA series was found to be within the standard deviation

Sea gulls are high trophic level consumers in the coastal environment, and thus, which have been widely used to monitor contamination biomagnified through a food web. However, such monitoring studies using sea gulls have been rare in the Korean literature. The National Environmental Specimen Bank chose eggs of a black-tailed gulls (Larus crassirostris) to serve as an environmental specimen for the long-term monitoring of the coastal ecosystem affected by terrestrial pollutants. Black-tailed gull eggs were collected from Baengnyeongdo, Hongdo and Uleungdo, and their DDTs and total mercury content were determined. The highest concentration of ΣDDTs was 231.6±106.1 μg/kg wet in Baengnyeongdo, followed by 230.0±123.8 μg/kg wet in Ulleungdo, and 117.7±18.3 μg/kg wet in Hongdo. In addition, total mercury was detected at 414.5±97.6 μg/kg wet in Ulleungdo, 363.9±123.6 μg/kg wet in Hongdo, and 237.5±42.3 μg/kg wet in Baengnyeongdo. Relatively high concentrations of the target pollutants were recorded in specimens from Ulleungdo. Additional comprehensive and prolonged studies are required to elucidate spatial and temporal patterns of contamination in black-tailed gull eggs with regard to monitoring contaminant trends in eggs and prey.

The National Environmental Specimen Bank (NESB) has been sampling and cryogenically preserving various wildlife specimens to monitor bio-accumulations of chemical pollutants since 2010. Recently, the NESB set up a plan to develop reference materials at their facility to assure the analytical quality of and validate the analytical methods for their monitoring samples. One of the crucial characteristics of reference materials is intra- and inter-bottle homogeneity. In this study, we used ANOVA for total mercury concentrations in some samples to validate their homogeneities after milling and homogenization. We examined the intra- and inter-bottle homogeneities of two cryogenically-milled samples (Korean mussel (Mytilus coruscus) and black-tailed gull’s egg (Larus crassirostris). The variations in the total mercury concentrations were not significantly different intra- and inter-bottle (mussel: F=0.74, p=0.67; gull egg: F=1.96, p=0.10). Additionally, the relative standard deviations of the total mercury concentrations showed low values (mussel: 2.02%, gull egg: 1.78%). Therefore, the cryogenic-milling process statistically proves the homogeneity of the materials of mussels and sea gull eggs for chemical analysis for total mercury.

In this study, we evaluated the photocatalytic oxidation efficiency of aromatic volatile hydrocarbons by using WO3–doped TiO2 nanotubes (WTNTs) under visible-light irradiation. One-dimensional WTNTs were synthesized by ultrasonic-assisted hydrothermal method and impregnation. XRD analysis revealed successful incorporation of WO3 into TiO2 nanotube (TNT) structures. UV-Vis spectra exhibited that the synthesized WTNT samples can be activated under visible light irradiation. FE-SEM and TEM images showed the one-dimensional structure of the prepared TNTs and WTNTs. The photocatalytic oxidation efficiencies of toluene, ethylbenzene, and o-xylene were higher using WTNT samples than undoped TNT. These results were explained based on the charge separation ability, adsorption capability, and light absorption of the sample photocatalysts. Among the different light sources, light-emitting-diodes (LEDs) are more highly energy-efficient than 8-W daylight used for the photocatalytic oxidation of toluene, ethylbenzene, and o-xylene, though the photocatalytic oxidation efficiency is higher for 8-W daylight.

본 연구는 시특법에 따른 비탈면 상태평가에 활용되는 절리암면비탈면의 가중치에 대한 수정안을 제안했다. 일반적으로 평가 항목 수정 및 각 항목별 가중치 부여와 항목별 평가 기준에 대한 연구는 Delphi 방법 및 AHP 방법 등 전문가의 경험에 의존하는 의사결정기법으로 결정되어 왔다. 본 연구에서는 보다 합리적인 결과를 얻기 위하여 기존의 주관적인 방법뿐만 아니라 비탈면의 점검 및 진단 데이터를 활용한 통계적 기법을 함께 활용하여 객관적인 가중치를 제시하고자 하였다. 본 연구에서는 절리암반 비탈면의 점검 데이터를 활용하여 엔트로피의 개념을 적용한 객관적인 가중치를 산정하고, AHP 기법에 의한 주관적 가중치는 전문가의 의견을 토대로 산정하였다. 그리고 두 가지를 결합하여 수정가중치가 제안하였으며, 그 결과, 도출된 절리암반 비탈면의 수정 가중치는 인위적 요인과 손상상태 항목들이 높은 가중치를 갖는 것으로 나타났다. 수정된 평가 기준을 향후 비탈면 세부지침 개정 등에 반영되면 보다 합리적인 절리암반 비탈면의 상태안정성 파악이 가능할것으로 판단된다.

In this study, a metal-organic framework (MOF) material NH2-MIL-101(Fe) was synthesized using the solvothermal method, and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-visible spectrophotometry, field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and surface area measurements. The XRD pattern of the synthesized NH2-MIL-101(Fe) was similar to the previously reported patterns of MIL-101 type materials, which indicated the successful synthesis of NH2-MIL-101(Fe). The FT-IR spectrum showed the molecular structure and functional groups of the synthesized NH2-MIL-101(Fe). The UV-visible absorbance spectrum indicated that the synthesized material could be activated as a photocatalyst under visible light irradiation. FE-SEM and TEM images showed the formation of hexagonal microspindle structures in the synthesized NH2-MIL-101(Fe). Furthermore, the EDS spectrum indicated that the synthesized material consisted of Fe, N, O, and C elements. The synthesized NH2-MIL-101(Fe) was then employed as an adsorbent and photocatalyst for the removal of Indigo carmine and Rhodamine B from aqueous solutions. The initial 30 min of adsorption for Indigo carmine and Rhodamine B without light irradiation achieved removal efficiencies of 83.6% and 70.7%, respectively. The removal efficiencies thereafter gradually increased with visible light irradiation for 180 min, and the overall removal efficiencies for Indigo carmine and Rhodamine B were 94.2% and 83.5%, respectively. These results indicate that the synthesized MOF material can be effectively applied as an adsorbent and photocatalyst for the removal of dyes.

This paper presents an image processing technique to detect carbonation region of concrete using a silhouette coefficient. From the test results, it was exhibited that the developed technique provided accurate detection of carbonation region of concrete.

Nitrogen budgets in Sihwa-ho in 2010 were estimated using a mass balance approach. Major nitrogen fluxes sources can be divided into three sections: cities, agricultural area, and forest. Surplus nitrogen 2,030~2,214 ton/yr (2,123 ton/yr in average) was discharged to Sihwa Lake. 20% of the surplus nitrogen is removed from the wetland and 60% is removed tidal flats. Therefore net nitrogen discharge from Sihwa basin is estimated to be 650 708 ton/yr (679 ton/yr in average). Wet and dry nitrogen deposition and load from non-point sources ware estimated to be 97 ton/yr and 69 ton/yr, deposition is using CAMx model. So estimated total nitrogen discharge into Sihwa-ho was 817 875 ton/yr (846 ton/yr in average). The atmospheric load explains 11.1 11.9% (11.5% in average) of the total nitrogen load Sihwa-ho.

Oxidative degradation of chlorinated ethenes was carried out using heat-activated persulfate. The activation rate of persulfate was dependent on the temperature and the activation reaction rate could be explained based on the Arrhenius equation. The activation energy of persulfate was 19.3 kcal/mol under the assumption that the reaction between the sulfate radical and tricholoroethene (TCE) is very fast. Activation could be achieved at a moderate temperature, so that the adverse effects due to high temperature in the soil environment were mitigated. The reaction rate of TCE was directly proportional to the concentration of persulfate, indicating that the remediation rate can be controlled by the concentration of the injected persulfate. The solution was acidized after the oxidation, and this was dependent on the oxidation temperature. The consumption rate of persulfate was high in the presence of the target organic, but the self-decomposition rate became very low as the target was completely removed.

This paper presents a force control based on the observer without taking any force or torque measurement from the robot which allows realizing more stable and robust human robot interaction for the developed multi-functional upper limb rehabilitation robot. The robot has four functional training modes which can be classified by the human robot interaction types: passive, active, assistive, and resistive mode. The proposed observer consists of internal disturbance observer and external force observer for distinctive performance evaluation. Since four training modes can be quantitatively identified as impedance variation, position-based impedance control with feedback and feedforward controller was applied to the assistive training mode. The results showed that the proposed sensorless observer estimated cleaner and more accurate force compared to the force sensor and the impedance controller embedded with the proposed observer completed the assistive training mode safely and properly.

This study investigated the tensile properties of UHPC using by PE fiber. Test results showed that the UHPC with PE fiber has high tensile strain capacity compared with UHPC with steel fiber. PE Fiber content was not effective of the strength. But increase the PE fiber content was improved of tensile strain capacity.

In this study, the flexural performance of concrete beams containing recycled aggregate was evaluated. The test variable are recycled coarse aggregate content of 0, 30, 50, and 100%. As a result of the analysis, the prediction result of the flexural strength of the concrete beam underestimates the actual flexural strength.

Due to recent climate changes, damage to the soundproof wall due to typhoons and strong winds is on the rise. This study determine the fragility curve of aluminum frame, which is a weak member of the soundproofing wall, due to strong wind. The fragility was analyzed in term of aluminum frame thickness variation. Finite element analysis of the wall was performed with ABAQUS, a commercial program. Random wind loads applied to the structures were generated using the Monte Carlo simulation technique. Also, the limit state was set based on the analysis results. The fragility curves were developed with consideration of three influential factors which are installation location, wind exposure and thickness aluminium frame of soundproof wall.

It is necessary to develop the damage function to cope with the increasing damage of steel transmission towers. A simplify analysis to evaluate the performance resistance capacity, which is essential for the development of the damage function, was performed. The 154kv power transmission towers installed between Sokcho and Yangyang were selected as the target structures. Wind loads were calculated and applied to the target structures according to the domestic transmission and distribution facility design standards. As a result of this study, displacement according to wind speed of the target structure was derived.

In this study, the reductive dechlorination of triclosan using zero-valent iron (ZVI, Fe0) and modified zero-valent iron (i.e., acid-washed iron (Aw/Fe) and palladium-coated iron (Pd/Fe)) was experimentally investigated, and the reduction characteristics were evaluated by analyzing the reaction kinetics. Triclosan could be reductively decomposed using zero-valent iron. The degradation rates of triclosan were about 50% and 67% when Fe0 and Aw/Fe were used as reductants, respectively, after 8 h of reaction. For the Pd/Fe system, the degradation rate was about 57% after 1 h of reaction. Thus, Pd/Fe exhibited remarkable performance in the reductive degradation of triclosan. Several dechlorinated intermediates were predicted by GC-MS spectrum, and 2-phenoxyphenol was detected as the by-product of the decomposition reaction of triclosan, indicating that reductive dechlorination occurred continuously. As the reaction proceeded, the pH of the solution increased steadily; the pH increase for the Pd/Fe system was smaller than that for the Fe0 and Aw/Fe system. Further, zero-order, first-order, and second-order kinetic models were used to analyze the reaction kinetics. The first-order kinetic model was found to be the best with good correlation for the Fe0 and Aw/Fe system. However, for the Pd/Fe system, the experimental data were evaluated to be well fitted to the second-order kinetic model. The reaction rate constants (k) were in the order of Pd/Fe > Aw/Fe > Fe0, with the rate constant of Pd/Fe being much higher than that of the other two reductants.

이 연구는 중학교 체육수업에서 경험하는 학생들의 즐거움 요인 및 즐거움 저해요인을 분석 하였다. 남녀 중학생 840명이 즐거움 요인과 저해요인을 묻는 개방형 설문지에 응답하였으며, 여기에서 얻은 1,178개의 즐거움 요인과 1,145개의 저해 요인의 원자료는 3단계 범주분석을 활 용하여 귀납적 내용분석을 실시하였다. 분석 결과 즐거움 요인으로는 신체 활동, 과제 학습, 긍 정적 정서, 사회적 상호작용의 4가지 범주가 확인되었고, 즐거움 저해요인은 비선호 과제, 유능 감 부족, 열악한 수업환경, 부정적 상호작용, 참여 제한의 5가지 범주가 확인되었다. 성별에 따 른 즐거움 요인은 ‘학습 경험’ 영역에서 다소 차이를 보였다. 남학생은 체육 활동 그 자체에 흥 미를 느끼는 반면에 여학생은 체육 활동 그 자체뿐만 아니라 과제를 학습하는 과정에서 상대 적으로 많은 즐거움을 느끼고 있었다. 즐거움 저해 요인에서는 여학생이 남학생에 비하여 상대 적으로 ‘운동 기량 부족’과 ‘ 위생 및 환경’ 요인에서 많은 반응을 보였다. 이와 같은 연구 결과 를 바탕으로, 체육교사는 학생 개개인이 선호하는 활동에 참여할 수 있도록 과제 선택의 폭을 넓혀주고 기량이 부족한 학생이나 여학생들을 위한 세심한 배려가 요구된다.

세계적인 경제위기에 맞물려 빈곤과 저소득층이 점차 증가하고 있는 추세로 가정의 위기, 부모의 부재 및 방임으로 인한 가족형태의 변화 로 낮은 자아개념과 자존감을 가지고 불안, 분노, 우울 등과 같은 정서적 문제를 경험하고 있으며, 대인관계에서도 위축감이 크다. 이러한 좌절감이나 열등감은 학교생활에서 또래로부터의 따돌림, 공격적인 행동, 학업성취의 어려움 등 대인관계에 어려움을 느끼며 또 다른 부 적응을 초래하기도 한다(배영옥, 2011). 원예활동은 심리적, 정서적 안정을 도모하고 긍정적인 삶의 태도를 형성하며 궁극적으로는 삶의 질을 높이는 것을 의미한다(김홍열, 2003). 따라서 본 연구는 심리적 적응단계를 이용한 원예치료 프로그램을 저소득층 아동에게 적용함 으로써 아동의 자아존중감에 어떠한 영향을 미치는지 알아보고자 실시하였다. 심리적 적응단계를 이용한 원예치료 프로그램을 저소득층 아동에게 적용함으로써 아동의 자아존중감에 어떠한 영향을 미치는지 알아본 결과 원예치료 프로그램 실시 후 학생들의 자아존중감 점수는 2.37(sd=0.28)에서 3.75(sd-0.13)로 1.38±0.24점이 증가하였고, 유의수준 1%하에서 통계적으로 유의한 것으로 나타났다(t=-11.638, p<0.01). 4개 하위영역을 살펴보면 일반적인 자아존중감의 경우 2.10점에서 3.80점으로, 사회적 자아존중감 2.50점에서 3.70점으로, 가정에서의 자아존중감은 2.20점에서 3.60으로, 학교에서의 자아존중감은 2.70 점에서 3.90점으로 모든 영역에서 향상됨을 볼 수 있었다. 이에 원예치료가 저소득 가정아동의 자아존중감 향상에 효과가 있음을 알 수 있 었다.

자아존중감은 스스로를 존중하는 마음 즉 자기 자신에 대한 긍정적인 마음이나 내적인 신념이다. 자아존중감을 통해 아동은 타인에게 공감 하고 배려하는 소통 방식을 터득하게 되고 어려운 난관을 극복할 수 있는 끈기와 문제해결능력을 얻게 된다(정지은 외 1, 2011). 아동에게 원 예치료는‘다양한 활동을 통해 아동의 호기심을 유발하여 집중력을 향상시키고 탐구심도 갖게 한다(손기철, 2014). 또한 육(2003)은 결손가 정과 정상가족 아동들에게 원예치료는 자신감을 회복시키고 긍정적인 사고, 그룹간의 활동으로 의사소통, 표현력, 대인관계를 향상 시킬 수 있다고 하였다. 이를 바탕으로 본 연구는 원예치료프로그램이 두드림 아동들의 자아존중감에 미치는 영향을 알아보고자 실시하였다. 본 연구는 연구측정 도구로 Rosenberg(1965)가 개발한 자아존중감척도 RSelf-Esteem Scale(RSES)를 사용하였다. 이 도구는 개인의 자아 즉, 자기 존중의 정도와 자아승인 양상을 측정하는 검사로서 긍정적 자아존중감 5문항과 부정적 자아존중감 5문항 등 총 10문항으로 구성 되어 있다. 원예치료 실시 전과 후 분석으로는 SPSS Windows 18.0 프로그램을 사용하였다. 원예치료프로그램을 실험군에게 적용한 후 사전, 사후 자아존중감 점수의 변화를 알아보기 위하여 대응표본 t-test를 분석한 결과는 자아 존중감의 사전 점수는 29.17점(sd=4.31), 사후 점수는 31.33점(sd=3.72)으로 2.17±1.94점이 증가하였고, 유의수준 5%하에서 통계적으로 유의한 것으로 나타났다(t=-2.735, p<0.05). 대상아동들의 행동변화를 회기별 작성된 관찰일지를 통해 알아본 결과 프로그램 초기의 경우에는 소극적인 자세로 의욕과 자신감이 없었 으며, 친구와의 작은 대립에도 욕을 하며 재료를 던지는 등의 과격한 모습을 보였지만, 회기가 거듭될수록 행동이 차분해졌고 표정도 밝아 졌으며 의사 표현도 하고 자기 작품에 만족감과 애착심을 느끼며 적극적으로 프로그램에 임하는 모습이었다. 따라서 원예활동은 성장과정 에서 환경적으로 긍정적 평가를 제한받았거나 정서상 문제행동에 대해 미흡했던 학생들의 자아존중감 향상과 정서적 안정에 효율적임을 알 수 있었다. 이에 원예교육 프로그램이 단기성이 아닌 지속적으로 이루어진다면 자아존중감이 더욱더 증진될 것이라고 기대한다.