The purpose of this study is to investigate the relationship of fine dust PM10 and heavy metals in PM10 in Asian dust flowing into Gwangju from 2013 to 2018. The migration pathways of Asian dust was analyzed by backward trajectory analysis using HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) model, and the change of heavy metal concentration and heavy metal content per 1 μg/m3 of fine dust PM10 in Gwangju area were analyzed. Also, the characteristics of the heavy metals were analyzed using the correlation between the heavy metals in PM10. As a result of analyzing Asian dust entering the Gwangju region for 6 years, the average concentration of PM10 measured in Asian dust was 148 μg/m3, which was about 4.5 times higher than in non-Asian dust, 33 μg/m3. A total of 13 Asian dust flowed into the Gwangju during 6 years, and high concentration of PM10 and heavy metals in that were analyzed in the C path flowing through the Gobi/Loess Plateau-Korean Peninsula. As a result of the correlation analysis, in case of Asian dust, there was a high correlation between soil components in heavy metals, so Asian dust seems to have a large external inflow. On the other hand, in case of non-Asian dust, the correlation between find dust PM10 and artificial heavy metal components was high, indicating that the influence of industrial activities in Gwangju area was high.

본 연구에서는 안동댐 퇴적물의 중금속 및 용출 특성을 분석하기 위하여 X-선 회절 분석, ICP 분석, 용출 실험을 수행하였다. X-선 회절 분석 결과 안동댐 퇴적물의 주구성 광물은 석영, 사장석, 녹니석, 일라이트이다. 퇴적물에 대한 ICP 분석 결과 비소와 카드뮴의 농도가 매우 높게 나타났다. 용출 실험은 교란 상태에서 호기성 및 혐기성 환경에서 수행하였다. 용출 실험 결과 혐기성보다 호기성 상태에서 더 많은 중금속이 용출되는 경향을 나타내었다. 호기성 상태에서 시간이 지남에 따라 농도가 증가하는 항목은 망간, 아연, 카드뮴이며 혐기성 상태에서는 망간, 철, 비소이다. 퇴적물 중금속 농도 대비 용출비는 호기성 및 혐기성 환경에서 각각 Mn > Cd > Zn > Ni > Cu > As > Pb ≒ Fe ≒ Cr이 며 Mn > As > Cu > Ni > Zn > Pb ≒ Cd ≒ Fe ≒ Cr이다.

산업화, 도시화로 인해 수자원의 오염이 악화 되면서 기존에 염소를 이용한 정수처리 방법으로는 깨끗한 물을 공급하는데 어려운 실정이다. 이에 오존을 이용한 고도정수 처리 시설의 도입이 증가하고 있다. 그러나 기존의 방수⋅방식 공법으로 사용되는 에폭시계 방수⋅방식제 및 스테인리스는 오존의 강력한 산화력으로 인해 열화되어 박리 등 문제 발생하였으며, 콘크리트까지 영향을 미쳐 내구성 저하의 원인이 된다. 이에 따라 본 연구에서는 내오존성 및 내화학성이 뛰어난 금속 패널을 기존의 시공법 보다 손쉬운 방법으로 시공하기 위한 방법으로 금속용사 공법을 이용하여 수처리 시설 콘크리트 구조물의 열화를 원천적으로 방지하기 위한 마감공법 개발 연구의 일원으로 용사금속 종류 에 따른 내오존성 평가를 실시하였으며, 실제 하수처리장 환경에서의 전기화학적 안정성능 평가를 실시하였다. 실험결과 용사금속 Ti이 용사 후에도 내오존성이 뛰어난 것으로 나타났으며, 하수처리장 환경에서의 전기화학적 안정성능 평가 결과 용사금속 Ti가 403.83k∙ Ω∙cm2의 가장 높은 분극저항을 나타남으로써 높은 수준의 내구성을 확보하는 것을 확인할 수 있었다.

섬유보강 시멘트계 복합재료 (이하 FRCC)는 균열 폭의 제어 등의 역학적인 효과뿐 아니라 철근방식에도 효과가 있는 것이 기존의 문헌으로부터 확인되고 있다. 본 연구에서는 아연섬유를 포함한 각종 금속섬유를 이용하여 철근의 방식효과를 부식 촉진 실험에 의해 검토했다. 더욱이 방식효과에 큰 영향을 미치는 염분침투, 희생양극 효과, 전기회로 형성에 주목하여, 각각의 요인에 있어서 검토를 실시했다. 그 결과, 금속섬유를 혼입한 FRCC의 방식효과를 확인할 수 있었으며, 특히 희생 양극효과가 높은 아연섬유의 경우, 염분침투 억제 효과가 뛰어나 내부식 성능이 향상되는 것을 확인할 수 있었다.

최근 남북한 사이에 화해의 분위기가 무르익어가고 있으므로, 미래에 발생할 한반도 통일을 대비하는 관점에서 남북한 사이의 광물명을 통일하여 사용하는 것이 절실히 요구되고 있다. 외래어 표기법에 다른 언어에서 빌려온 어휘를 한글로 표기하는 규정이 있음에도 불구하고 광물명의 경우 이를 준수하지 않고 같은 외래어 광물명에 대하여 다양한 용어를 사용하고 있으므로 외래어 표기법에 맞도록 통일해야 한다. 금속광물과 비금속광물 모두에 ○○○석을 사용하고, 외래어 표기법 용례 찾기에 포함된 약 70개의 광물명은 용례 찾기에 나와 있는 대로 표기하고, 인명이나 지명에서 유래한 광물명은 인명이나 지명 + 석으로 표기할 것을 제안한다.

본 연구에서는 안동댐과 임하댐의 퇴적물과 유입되는 부유물의 특성을 색도분석, X-선회절분석 및 유도플라즈마/질량분석법을 이용하여 분석하였다. 안동댐과 임하댐으로 유입되는 부유물 및 댐 퇴적물의 광물조성은 석영, 사장석, 녹니석, 일라이트이며 소량의 몬모릴로나이트와 캐올리나이트를 포함하고 있다. 안동댐 퇴적물과 다르게 임하댐 퇴적물에는 다량의 방해석을 포함하고 있다. 색도는 시료에 따라 약간의 차이가 있지만 회갈색에서 어두운 주황색 정도이다. 퇴적물의 중금속 농도는 안동댐이 임하댐보다 더 높다. 안동댐과 임하댐 퇴적물과 유입 부유물질의 주요 중금속 농도는 미국의 국립해양대기관리청의 기준을 적용할 경우 높은 오염도를 나타낸다. 안동댐 퇴적물의 중금속 농도가 임하댐보다 높은 것은 안동댐으로 유입되는 부유물질의 중금속 농도가 임하댐으로 유입되는 부유물질의 중금속 농도보다 높기 때문이다.

Nowadays micro-dust is a serious problem in Korea. In particular micro-dust contains heavy metals such as Pb (lead) and Cd (cadmium) which negatively effect on human health. In this study, we intended to isolate lactic acid bacteria which can scavenge the heavy metals. Firstly we isolated two lactic acid bacteria which were resistant to Ag, Cu, and Zn (30-100 mM AgNO3, CuSO4, ZnSO4 in MRS broth). The two lactic acid bacteria CJNU 1877 and JG 15 were identified Lactobacillus paracasei and Enterococcus faecium, respectively. Subsequently the strains were inoculated in MRS broth and agar plate where 100 ppm of Pb(NO3)2 and CdSO4 were added, respectively. They did grow in the conditions and we found aggregations from 24 h cultures, indicating the strains can absorb the heavy metals, which was further proved by scanning electron microscopy (SEM) and Inductively Coupled Plasma-Optical Emission Spectrometer. Therefore the isolated lactic acid bacteria can be used as a probiotics harboring heavy metal scavenging activity.

Recently, due to advancement in construction techniques, structures are being constructed much faster than before. Therefore, structures such as cable stayed bridges and suspension bridges, must be inspected regularly to assure their main elements (i.e., load carrying cables) are healthy and sound. Structures can be tested using conventional nondestructive testing methods such as magnetic flux leakage (MFL), eddy current testing, acoustic emission and etc. In this study, it was tried to detect cross sectional reduction in steel rod using a time dependent numerical simulation of coil sensor based on MFL principle.

본 연구는 중금속 오염지역의 토양정화에 적합한 식물을 선발하기 위해 국화과 15종을 중금속으로 오염된 토양에 8주 동안 재배한 다음 생육반응과 부위별 비소, 카드뮴, 구리, 납, 아연 등의 중금속의 축적능을 분석하였다. 톱풀을 제외한 가새쑥부쟁이, 금계국, 감국, 각시취 등의 생육은 비교적 양호하였다. 비소 축적능은 더위지기 지하부(25.52 ㎎·㎏-1)에서 가장 높았고 지상부는 바위구절초(3.35 ㎎·㎏-1)가 가장 우수하였다. 카드뮴은 왕갯쑥부쟁이 지상부(2.50 ㎎·㎏-1)에서 가장 높았다. 구리 축적능은 지상부와 지하부 모두 각시취(24.29, 99.92 ㎎·㎏-1)가 가장 높은 경향을 보였다. 국화과 15종의 지상부는 1.43(왕갯쑥부쟁이)∼5.00 ㎎·㎏-1(수리취)의 납이 축적되었다. 눈갯쑥부쟁이(140.09 ㎎·㎏-1), 쑥부쟁이(109.07 ㎎·㎏-1), 왕갯쑥부쟁이(100.21 ㎎·㎏-1) 등의 아연 축적능은 100 ㎎·㎏-1 이상으로 아연 오염 지역의 식물상 정화 기법 소재로 활용이 가능할 것으로 생각된다.

We investigated the effects of heavy metals in cement in the last 3 years and the amount of waste in the cement manufacturing process. The result shows that the average Cr6+ content in cement products is controlled at 10 mg/kg. Cu and Pb have lower detection tendency in white cement than in ordinary portland cement. In addition, heavy metals such as Cd show a certain level of detection regardless of the input wastes. Copper slag and phosphate gypsum are the main influencing factors on the heavy metals in cement products. In auxiliary fuels, plastics waste and wood waste are considered to affect heavy metals in cement products. Alternative raw materials are considered to be affected by the alternative raw materials managed as byproducts. In the case of supplementary fuels, auxiliary fuels managed as waste instead of auxiliary fuels managed as byproducts affect the heavy metals in cement. This study examined the input amount without considering the heavy metals in each waste. Therefore, the result may vary in different situations, and further research must be conducted to supplement the findings. However, if the heavy-metal contents in the waste are constant, it can be used as a reference material for the control of heavy metals in cement products.

Bioremediation has been recognized as a suitable alternative to conventional methods of removing contaminants, and it uses fungi, bacteria and microalgae. In contrast to other organisms, microalgae are unique in that they have the ability to perform photosynthesis like plants and to utilize organic/inorganic carbon substrates, in a process called phytoremediation. Microalgae can populate a reaction site rapidly and enhance the bioremediation efficiency. In this study, Chlorella vulgaris was used to evaluate the removal potentials of the nutrients (N and P) and heavy metals (Cu and Zn) from swine wastewater. The optimum growth conditions for Chlorella vulgaris and the removal potentials of N, P, Cu, and Zn from synthetic wastewater using Chlorella vulgaris were investigated. Based on the results, the applicability of this microalga to on-site wastewater treatment was examined. Optimal growth conditions for Chlorella vulgaris were established to be 28℃, a pH of 7, and light and dark cycles of 14:10 h. As the concentrations of the nutrients were increased, the efficiencies of N and P removal efficiencies by Chlorella vulgaris were decreased in the single and binary mixed treatments of the nutrients, respectively. Further, the efficiencies of Cu and Zn removal also decreased as the heavy metals concentrations added were increased, both in the single and binary mixed treatments. In addition, the efficiency of Cu removal was higher than that of Zn removal. Our results indicate that Chlorella vulgaris could be used in treatment plants for the removal of nutrients and heavy metals from swine wastewater.

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.

Trains have been a major means of transport in Korea during these past decades. However, train facilities such as stations and repair shops are contaminated with organic and inorganic substances. There is a high probability of train facility contamination with polyaromatic hydrocarbons (PAHs). This study evaluated the PAH and heavy metal contamination of soil near railroads in the Kyungpook area. A total of 18 soil samples were collected from the railroads and analyzed for 16 PAHs and 6 heavy metal species. The contamination level of the top soil was found to be slightly higher than that of the subsoil for contamination with PAHs. The ratio of carcinogenic PAH concentration to the total PAH concentration was relatively high, with a maximum of 0.9. The toxicity equivalent (TEQ) of the PAHs were 500.6 ng/kg in the topsoil and 355.5 ng/kg in the subsoil. The ratio of low molecular PAHs (LPAHs) to high molecular PAHs (LPAHs) ranged from 6.7 to 29.5; this shows that contamination is primarily due to combustion of fuel rather than due to petroleum. The ratio of phenanthrene to anthracene and the ratio of fluoranthene to pyrene also show that contamination occurred due to combustion for transportation. The heavy metal contamination level was lower than the Korean standard, but higher than the background concentration; this indicates that the soil was affected by the operation of the railways.

The quality standards of solid refuse fuel (SRF) define the values for 12 physico-chemical properties, including moisture, lower heating value, and metal compounds, according to Article 20 of the Enforcement Rules of the Act on Resource Saving and Recycling Promotion. These parameters are evaluated via various SRF Quality Test Methods, but problems related to the heavy metal content have been observed in the microwave acid digestion method. Therefore, these methods and their applicability need improvement. In this study, the appropriate testing conditions were derived by varying the parameters of microwave acid digestion, such as microwave power and pre-treatment time. The pre-treatment of SRF as a function of the microwave power revealed an incomplete decomposition of the sample at 600 W, and the heavy metal content analysis was difficult to perform under 9 mL of nitric acid and 3 mL of hydrochloric acid. The experiments with the reference materials under nitric acid at 600 W lasted 30 minutes, and 1,000 W for 20 or 30 minutes were considered optimal conditions. The results confirmed that a mixture of SRF and an acid would take about 20 minutes to reach 180 oC, requiring at least 30 minutes of pre-treatment. The accuracy was within 30% of the standard deviation, with a precision of 70 ~ 130% of the heavy metal recovery rate. By applying these conditions to SRF, the results for each condition were not significantly different and the heavy metal standards for As, Pb, Cd, and Cr were satisfied.

Proximal femoral fractures are common in older adults. Zimmer natural nail (ZNN, Cephalomedulary Asia; Zimmer, Warsaw, IN, USA) known as useful in immobilizing the fractures of the proximal femoral fractures, have a critical complications like femoral head perforation and cut through in pelvic bone. We report a case that the femoral head perforation by the hip screw occured within 2 months of the operation, and 8 months after operation, the hip screw is completely separated from the metal body and cut through the pelvis.

We evaluated the radiologic, clinical results and the complications of minimally invasive percutaneous medial plate fixation in distal tibial metaphyseal fracture. From January 2010 to December 2016, 31 patients with distal tibial fracture treated by medial plate fixation using Minimal Invasive Plate Osteosynthesis (MIPO) technique were analyzed. The duration of followup was more than 1 year. We evaluated clinical results by IOWA ANKLE rating system, union time by simple X-ray and complication. The bone union was achieved in all cases at average 16.7 weeks. Average IOWA ANKLE rating score was 90.3 point. At the last follow-up, there was no non-union, angular deformity more than 5 degrees or infection. We concluded that minimal invasive percutaneous medial plate fixation for distal tibial metaphyseal fractures is a safe and useful method if there is no medial wound problem, and it is important to pay close attention to prevent angular deformity during surgery.

본 연구에서는 대전 관평천의 도시유역에서 2017~2018년에 발생한 강우 20건의 유출수를 연속적으로 채취하여 As, Cd, Cr, Cu, Ni, Pb 및 Zn 의 중금속 및 총고형물질(TSS) 농도와 유량을 분석하고, 강우특성과 수질 변화의 강우사상별 및 시간별 상관관계를 조사하였다. 일정 강우강도에서 오염물질의 최대농도는 강우 초기에 발생하는 경향을 나타냈으나, 강우량 및 강우강도가 작은 경우에는 일정 시간 경과 후 발생하는 것이 관찰 되었다. 강우지속시간은 중금속 농도 및 부하량과 큰 상관성을 보이지 않았다. Cu와 Zn을 제외한 중금속 질량은 강우강도(0.60~0.88) 및 총강우 유출량(0.74~0.89)과 상대적으로 높은 상관관계를 나타냈다. 강우 시 유량가중평균농도와 선행무강우일수 또한 양의 상관성(0.54~0.73)을 보 이는 반면, 30분 강우강도로 표현된 시간별 유출량과 TSS 및 중금속 농도는 전혀 상관성을 나타내지 않았다. 무강우 기간 동안 지표면에 축적된 오 염물질이 최소한의 강우 에너지에도 세척효과가 발생하여 강우특성과는 무관하기 때문인 것으로 추정된다. 중금속과 TSS 농도의 시간에 따른 변화특성은 상관계수가 0.68~0.87로 양호한 수준을 나타냈다. 이는 고형물질의 이동과 중금속 물질의 이동이 함께 발생한다는 것을 시사하며 동시에 중금속이 고형물질에 흡착되어 이동한다는 것을 의미한다. 따라서 비강우 시에 유역 표면의 고형물질을 청소 등으로 사전에 제거할 경우 하천으로 유입되는 중금속오염물질의 양을 현격하게 저감할 수 있을 것으로 판단된다.

This study is an attempt to develop modular house structural systems with safety seismic performances under maximum seismic load of 0.3G. The modular house system was designed with joints (plan) using four-clip simple fastening type, and was also adopted a type of double inter-metallic assembly modular systems using a light metal. The seismic performance was evaluated.

The purpose of this study is to investigate the ultimate strength of carbon steel (SS400) fillet-welded connections with weld metal fracture through monotonic tensile test. Specimens of CTFW series (transverse fillet weld against loading direction), CLFW series (longitudinal fillet weld against loading direction) and CFW series (a combination of transverse weld and longitudinal weld) failed by tensile fracture, shear fracture and block shear fracture, respectively. Test strengths were compared according to welding direction and weld length

The purpose of this experimental study is to develop an water soluble silicone acrylic surface finishing material of car parks. The heavy metal contents test was conducted in order to supply a guideline for developing a top finishing material. As a results, the sample was satisfied with the quality standard regarding heavy metal contents which is prescribed in KS F 3888-2 of En 71-3. As conclusion, this study confirmed that the developed top finishing material could be an optimized material usable for car parks’ deck.