• Journal of Radiation Protection and Research
• /
• 제42권1호
• /
• pp.16-20
• /
• 2017

Background: The design of deuteron accelerator neutron source facilities requires reliable yield estimation of gamma-rays as well as neutrons from deuteron-induced reactions. We have so foar measured systematically double-differential thick target neutron yields (DDTTNYs) for carbon, aluminum, titanium, copper, niobium, and SUS304 targets. In the neutron data analysis, the events of gamma-rays taken simultaneously were treated as backgrounds. In the present work, we have re-analyzed the experimental data for a thick carbon target with particular attention to gamma-ray events. Materials and Methods: Double-differential thick target gamma-ray yields from carbon irradiated by 5 and 9 MeV deuterons were measured using an NE213 liquid organic scintillator at the Kyushu University Tandem accelerator Laboratory. The gamma-ray energy spectra were obtained by an unfolding method using FORIST code. The response functions of the NE213 detector were calculated by EGS5 incorporated in PHITS code. Results and Discussion: The measured gamma-ray spectra show some pronounced peaks corresponding to gamma-ray transitions between discrete levels in residual nuclei, and the measured angular distributions are almost isotropic for both the incident energies. Conclusion: PHITS calculations using INCL, GEM, and EBITEM models reproduce the spectral shapes and the angular distributions generally well, although they underestimate the absolute gamma-ray yields by about 20%.

• 한국대기환경학회지
• /
• 제27권4호
• /
• pp.460-471
• /
• 2011

A port has been regarded as a significant contributor to air pollution in the surrounding areas. Port-related air pollutants are released from not only marine vessels, but also various land-side sources at ports, which include cargo handling equipment, vehicles, locomotives, and fugitive dust sources by port activities such as bulk handling and vehicle movements. However, most studies in Korea have only focused on vessel emissions and there is a lack of information on the emissions from other sources at port. In this study, in order to establish the port-related emission inventory and evaluate the relative contribution of these sources to air emissions from the Port of Incheon, the emissions from land-side sources were estimated and the CAPSS (Clean Air Policy Support System) data for vessel emissions were used. In particular, the detailed information and activity data for the cargo handling equipment source were collected and the emission factors and emissions by equipment types were calculated using U.S. EPA methodologies. Total HC, CO, $NO_x$, $PM_{10}$, and $SO_2$ emissions from port-related sources including the vessel in 2007 were calculated as 229 ton/year, 638 ton/year, 4,861 ton/year, 307 ton/year, and 3,995 ton/year, respectively. It was found that the vessel was the largest contributor to air pollutant emissions from the port, the cargo handling equipment was responsible for about from 8% to 13% of HC, CO, and $NO_x$ emissions and the resuspended road dust contributed about 39% for $PM_{10}$ emissions. The results of this study will be used to establish the management and reduction strategies of air pollution in the port.

• 한국대기환경학회지
• /
• 제32권2호
• /
• pp.193-207
• /
• 2016

This study discusses the present status of mercury emission and distribution from major anthropogenic sources in Korea and the future trend of mercury emission by activity changes and application of BATs. Atmospheric mercury emission from major anthropogenic sources based on Annex D of Minamata convention was estimated to around 4.89 tonne in 2012. Emission ratios of cement clinker production, coal-fired power plant, waste incineration and non-ferrous metal smelting were 68.68%, 24.75%, 6.29% and 0.28%, respectively. High mercury emission regions were characterized by the presence of cement clinker production facilities and coal-fired power plants. Prediction of future activities was carried out by linear regression of the previous year data. The (total) mercury emission was estimated to decrease up to 48% Under the scenario of BATs to be applied and the change of future activities. Emissions from coal-fired powerplants and cement clinkers were expected to decrease significantly.

• Computers and Concrete
• /
• 제20권4호
• /
• pp.369-380
• /
• 2017

The effects of the vertical component of a ground motion on the earthquake performances of semi-ductile high-rise R/C structures were investigated in the present study. Linear and non-linear time-history analyses were conducted on an existing in-service R/C building for the loading scenarios including and excluding the vertical component of the ground motion. The ratio of the vertical peak acceleration to the horizontal peak acceleration (V/H) of the ground motion was adopted as the main parameter of the study. Three different near-source earthquake records with varying V/H ratio were used in the analyses. The linear time-history analyses indicated that the incorporation of the vertical component of a ground motion into analyses greatly influences the vertical deflections of a structure and the overturning moments at its base. The lateral deflections, the angles of rotation and the base shear forces were influenced to a lesser extent. Considering the key indicators of vertical deflection and overturning moments determined from the linear time-history analysis, the non-linear analyses revealed that the changes in the forces and deformations of the structure with the inclusion of the vertical ground motion are resisted by the shear-walls. The performances and damage states of the beams were not affected by the vertical ground motion. The vertical ground motion component of earthquakes is markedly concluded to be considered for design and damage estimation of the vertical load-bearing elements of the shear-walls and columns.

• 대한환경공학회지
• /
• 제22권1호
• /
• pp.149-157
• /
• 2000

깅릉 남대천 수계에서 처음으로 용존 비소(As)의 분포와 거동에 관한 연구가 수행되었다. 풍수기인 1997년 8월 28일(최종 방류량; $1.97{\times}10^6$ 톤/일)과 갈수기인 동년 11월 21일(최종 방류량; $0.13{\times}10^6$ 톤/0일). 두 차례에 걸쳐 조사된 As의 농도 분포는 같은 시기에 조사된 다른 중금속들과 다소 차이를 보인다. 도암댐 보다 오봉댐 유출수의 농도가 미소하게 높았고, 갈수기인 11월 하류부의 농도 급증현상도 나타나지 않았을 뿐 아니라 풍수기인 8월 하류부의 농도보다도 낮았다. 그리고 두 조사기간사이의 농도차가 미비하며, 원시적인 강들과 세계평균치에 비해서도 비교적 낮은 농도로서 남대천 수계에서는 As의 인위적인 오염원이 없고, 자연적인 배경농도(background level) 수준임을 알 수 있다. 하구에서 담수와 해수가 혼합되는 과정에서는 외부 유입이나 제거 기작없이 염분과 함께 직선적으로 증가하는 보존적인 분포를 보이며, 남대천을 통하여 동해로 유출되는 As의 양은 연간 65.12kg 정도이다.

• Environmental Analysis Health and Toxicology
• /
• 제23권4호
• /
• pp.257-265
• /
• 2008

Nanotechnology is emerging as one of the key technologies of the 21 st century and is expected to enable one to broaden the applicability across a wide range of sectors that can benefit public and improve industrial competitiveness. Already, consumer products containing nanomaterials are available in markets including coatings, computers, clothing, cosmetics, sports equipment and medical devices. Recently, Institute of Occupational Medicine in UK reported an occupational hygiene review for nanoparticles in the viewpoint of nanotoxicity. They reported that the exposure control is very important issues in workplace for exposure assessment, but no proper methods are available to measure the extent of exposures to nanoparticles in the workplace. Therefore, for the estimation of exposure of nanomaterials, we have to approach the material-balance methodology, which similarly carried out in TRI (toxic release inventory) for hazardous chemicals. In order to use this methodology, the exposure source of nanomaterials should be determined firstly. Therefore, herein we investigated the main sources and processes for the exposure to nanomaterals by conducting the survey. The results could be used to define and assess nanohazard sources.

• 한국환경농학회지
• /
• 제27권1호
• /
• pp.10-17
• /
• 2008

The objective of this study was to estimate the pollutant loads from paddy fields by cultivation practices using a non-point-sources models. One of them is CREAMS-PADDY model that was developed considering the water balance and mass balance of paddy fields. The CREAMS-PADDY model was applied to provide basic data to reduce runoff loadings under various scenarios such as various water management control and various fertilizer condition. The model was verified against T-N, T-P and runoff flow data collected during cropping periods at 2000. The model results agreed well with the measured data in verification. The results showed that the model could be used for estimating the runoff loadings from irrigated paddy fields by cultivation practices was possible. Comparison of simulated the standard height and the sluice management of T-N and T-P runoff loadings from paddy fields were +32.4%, +10.3% in 10 mm below the standard height, -29.2%, -35.9% in 20 mm above the standard height, 52.6%, 59.0% in 40 mm above the standard height, respectively. Comparison of simulated the standard fertilizer and the fertilizer control of T-N and T-P runoff loadings from paddy fields were -1.3%, -21.7%in reduction of conventional fertilizer 30%, -1.0%, -12.5% in reduction of standard fertilizer 30%, respectively. Therefore, reducing nonpoint-sources nutrient loading by reducing fertilization may not work well in the range of normal paddy rice farming practices, and instead it could be achieved by reducing surface drainage outflow.

• 정보처리학회논문지:소프트웨어 및 데이터공학
• /
• 제2권2호
• /
• pp.145-150
• /
• 2013

색 오버레이는 광과민성 증후군의 증세를 완화시키는 보조도구로 사용되어 왔다. 최근에 컴퓨터에서 사용할 수 있는 몇 종의 가상 색 오버레이가 개발되었으나, 모바일 환경에서 사용할 수 있는 것은 발표된 바 없다. 본 논문에서는 안드로이드의 최상위 윈도우를 활용하여 가상 색 오버레이를 이동시키지 않고 겹쳐진 앱이나 화면을 제어할 수 있는 모바일용 가상 색 오버레이를 구현하였다. 분광측색계를 이용하여 필름 오버레이의 색도 정보와 투과율을 측정하여 가상 색 오버레이에 적용할 색상정보를 추정하는 방법을 제안하였고, Intuitive Overlays에서 표현하는 모든 색상을 구현하였다. 시험 결과 기존의 필름 오버레이를 사용한 것과 동일한 효과를 얻었다.

• 대한지하수환경학회지
• /
• 제6권3호
• /
• pp.107-110
• /
• 1999

제주도 지하수중 질산염농도가 높은 지점을 선정하여 1995년부터 1996년까지 4차에 걸쳐 질소안정등위원소의 자연존재를 측정하고. 오염원별 기여율을 계산한 결과는 다음과 같다. 화학비료에 의한 영향이 뚜렸하게 나타나는 지점은 T-3, L-1. O-1∼O-4. F-2∼F-5. G-2의 11개소로써 화학비료 질소성분이 지하수 질산염농도 중 약 60% 이상을 차지하는 것으로 조사되었다. 그리고. 동물성 유기물질에 의한 영향이 많은 지하수는 T-4, T-5. G-2지점 3개소이며, T-4, T-5지점은 생활하수에 의한 영향으로, G-2지점은 쓰레기매립장 침출수의 영향으로 사료된다. 또한. 화학비료와 동물성 유기물질에 의한 영향을 비슷하게 받는 지하수는 T-1, T-2. L-2. F-1지점 4개소로 조사되었다.

• 한국물환경학회지
• /
• 제23권4호
• /
• pp.490-497
• /
• 2007

A Combined sewer overflows (CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available (which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a continuous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban drainage system used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range $3{\times}DWF$ (dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a decision of storage volume for CSOs reduction and water quality protection.