• Title/Summary/Keyword: Non-point

검색결과 4,057건 처리시간 0.032초

The Measurement of Flash Point for Binary Mixtures of 2,2,4-Trimethylpentane, Methylcyclohexane, Ethylbenzene and p-xylene at 101.3 kPa

  • Hwang, In Chan;In, Se Jin
    • 청정기술
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    • 제26권4호
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    • pp.279-285
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    • 2020
  • Laboratories and industrial processes typically involve the use of flammable substances. An important property used to estimate fire and explosion risk for a flammable liquid is the flash point. In this study, flash point data at 101.3 kPa were determined using a SETA closed cup flash point tester on the following solvent mixtures: {2,2,4-trimethylpentane + methylcyclohexane}, {2,2,4-trimethylpentane + ethylbenzene}, and {2,2,4-trimethylpentane + p-xylene}. The purpose of this work is to obtain flash point data for binary mixtures of 2,2,4-trimethylpentane with three hydrocarbons (methylcyclohexane, ethylbenzene, and p-xylene), which are representative compounds of the main aromatic hydrocarbon fractions of petroleum. The measured flash points are compared with the predicted values calculated using the GE models' activity coefficient patterns: the Wilson, the Non-Random Two-Liquid (NRTL), and the UNIversal QUAsiChemical (UNIQUAC) models. The non-ideality of the mixture is also considered. The average absolute deviation between the predicted and measured lower flash point s is less than 1.99 K, except when Raoult's law is calculated. In addition, the minimum flash point behavior is not observed in any of the three binary systems. This work's predicted results can be applied to design safe petrochemical processes, such as identifying safe storage conditions for non-ideal solutions containing volatile components.

영산강수계 비점오염원 중점관리지역 선정에 관한 연구 (A Study on the Selection of Non-point Pollution Management Regions with High Priority Order in the Yeongsan River Basin)

  • 이재춘;박혜린;임병진;이창희;이수웅;이용운
    • 생태와환경
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    • 제45권4호
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    • pp.347-355
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    • 2012
  • In this study, non-point pollution sources in the Yeongsan river basin are analyzed; then, the priority regions (areas divided on a small scale) of management are selected for efficient water management of the Seungcheon and Jooksan reservoirs, which were constructed as one of the 4 major rivers restoration projects. The priority regions are decided by using the criteria of the excessive rate of target water quality, non-point pollution load per unit area, total TP load and down flow distance. The results of this study are as follows. The upper 10% of the priority regions for non-point pollution management includes YB15, YB05, YB10, YB24, YB14 and YB11 for the Seungcheon reservoir watershed, and YC24, YC25, YC30, YC34, YC22 and YC17 for the Jooksan reservoir watershed. However, a few regions in each of the Seungcheon and Jooksan reservoirs need to be selected in higher order, and the non-point pollution removal facilities in the regions need to be installed with respect to budget, urgent matter, and so on.

토지피복별 비점부하량 기여율 해석을 위한 분포형 모델 개발 및 적용 (Development and Application of the Grid-Distributed Model for Contribution Rate Analysis on Non-point Source Pollution According to Landuse)

  • 안정민;정강영;김신;이혜진;신석호;양득석;신동석;나승민
    • 한국물환경학회지
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    • 제33권1호
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    • pp.78-89
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    • 2017
  • Water quality monitoring network data is being affected continuously due to non-point source pollution arising from agricultural land located on the Gwangsancheon outlet in the Nakdong River basin. In this study, we have performed analysis of water quality monitoring system, water quality pattern using SOM and water quality in the Gwangsancheon for sub-basin located at Gisan-myeon in the Nakdong River basin. We have developed and applied the model to estimate the runoff and non-point source loading. As a result of SOM pattern, the effect of non-point source pollution was the largest in the paddy fields and fields. As a result of the developed model, we found contribution rate and reduction rate for non-point source loading according to change of landuse because the reduction effect of nonpoint pollutants was 20.9% of SS, 9.9% of TN, 21.2% of TP and 8.9% of TOC depending on the landuse change.

도암호 유역 송천에서의 강우유출수 분석을 통한 EMC와 초기세척비율 (MFFn) 산정 (Determination of EMC and MFFn Rainfall Runoff in Songcheon, Doam Lake Watershed)

  • 권혁준;김종건;임경재;김동진;홍은미
    • 한국농공학회논문집
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    • 제62권4호
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    • pp.13-22
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    • 2020
  • The Doam Lake watershed has a significant impact on the downstream water system due to nutrients and sediment outflow during rainfall caused by steep slopes, soil losses, and fertilization. These non-point sources are unclear in the discharge area and are affected by land use patterns, soil characteristics, and topographical features of the watershed. Therefore, this study conducted rainfall monitoring from July to October 2019 in Songcheon upstream of the Doam Lake watershed, one of the non-point pollution source management areas. Then, after analyzing rainfall runoff, Event Mean Concentration (EMC) and Mass First Flush ratio (MFFn) were calculated to compare and analyze the characteristics of rainfall and the non-point pollutant discharge. As a result of the analysis, it showed various non-point pollutant emission characteristics for each rainfall event. In addition, the concentration of EMC and the MFFn were affected by the average rainfall intensity and the maximum rainfall intensity, and were not significantly affected by the number of antecedent drying days. In the future, it is expected that effective non-point source reduction measures and management measures according to rainfall intensity through continuous monitoring and analysis will be needed.

지르코니아 코어와 전장용 세라믹의 결합 강도에 대한 표면 처리 방법 평가 (Evaluation of surface treatment methods on the bond strength of veneer ceramic to the zirconia core)

  • 이광영;홍민호
    • 대한치과기공학회지
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    • 제42권3호
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    • pp.213-219
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    • 2020
  • Purpose: This study aimed to identify the impact of physical surface roughing with a polishing tool onto the pre-sintering yttria-stabilized tetragonal zirconia polycrystals (TZP) core and liner treatment for chemical bonding on the bond strength of TZP core and veneering ceramic. Methods: Overall, 80 specimens were classified into two groups (non-liner, NL; and usingliner, UL ) depending on the use of liner, and these two groups were then subclassified into four groups depending on the polishing tool used. (1) Non-liner groups: NS, non-liner+stone point; NC, non-liner+carbide bur; NP, non-liner+paper cone point; NT, non-liner+silicon point. (2) Using-liner groups: US, using-liner+stone point; UC, using-liner+carbide bur; UP, usingliner+paper cone point; UT, using-liner+silicon point. The pre-sintering surface roughing values and shapes were observed, and after burning up the veneering ceramic, the shear bond strength was measured using a universal testing machine. For significance testing, a one-way analysis of variance and Tukey's multiple comparison test were conducted. An optical microscope was used to observe the fracture plane, and the following results were obtained. Results: Surface roughness NP (4.09±0.51 ㎛) represented a higher value than other groups (p<0.001). In shear bond strength, NS (35.21±1.44 MPa) of the NL group showed the highest bond strength (p<0.001). The UL group did not show a statistically significant difference between groups (p=0.612). Conclusion: Our study findings reveal that the bond strength of TZP core and veneering ceramic was improved by pre-sintering physical surface treatment than by chemical bonding with liner surface treatment.

투수성 포장재와 비점오염저감시설의 삭감부하량 특징 비교 (Reduced Loads Characteristics Comparison Between Permeable Pavement and Non-point Pollutants Treatment Facility)

  • 길경익;전혜선
    • 한국방재학회 논문집
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    • 제11권2호
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    • pp.193-198
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    • 2011
  • 본 연구에서는 최근 추세에 맞춰 개발사업시 장치형 및 자연형등의 인위적인 비점오염저감시설이 아닌 시설지를 투수성 포장재를 사용할 경우 얻어지는 효과를 분석하여, 설계 및 시공시 투수성 포장재 적용을 위한 기초자료를 제공하고자 한다. 그 방법으로 개발시 대상지의 면적을 불투수성과 투수성 개발로 분리 적용하여 삭감오염부하량 및 설치 공사비의 경제성을 비교 분석하였다. 그 결과 비점오염원의 처리용량 및 삭감부하량은 투수성 및 불투수성 개발에 많은 영향을 받으며, 개발시 비점오염저 감시설을 장치형이나 자연형을 단독으로 설치하기 보다는 처리대상 유역을 투수성 지역으로 개발하는 것이 배출부하량이 적은것으로 나타났다. 이를 토대로 개발시 비점오염의 관리를 위해 불투수율 면적비를 일정수준으로 제한하는 대책을 수립하면 개발에 따른 오염원의 최소화가 가능할 것으로 생각된다.

계절예측 정보 기반 APEX-Paddy 모형 적용성 평가 (Evaluation of Applicability of APEX-Paddy Model based on Seasonal Forecast)

  • 조재필;최순군;황세운;박지훈
    • 농촌계획
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    • 제24권4호
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    • pp.99-119
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    • 2018
  • Unit load factor, which is used for the quantification of non-point pollution in watersheds, has the limitation that it does not reflect spatial characteristics of soil, topography and temporal change due to the interannual or seasonal variability of precipitation. Therefore, we developed the method to estimate a watershed-scale non-point pollutant load using seasonal forecast data that forecast changes of precipitation up to 6 months from present time for watershed-scale water quality management. To establish a preemptive countermeasure against non-point pollution sources, it is possible to consider the unstructured management plan which is possible over several months timescale. Notably, it is possible to apply various management methods such as control of sowing and irrigation timing, control of irrigation through water management, and control of fertilizer through fertilization management. In this study, APEX-Paddy model, which can consider the farming method in field scale, was applied to evaluate the applicability of seasonal forecast data. It was confirmed that the rainfall amount during the growing season is an essential factor in the non-point pollution pollutant load. The APEX-Paddy model for quantifying non-point pollution according to various farming methods in paddy fields simulated similarly the annual variation tendency of TN and TP pollutant loads in rice paddies but showed a tendency to underestimate load quantitatively.

강우 시 수영강 유역의 수질변화 특성 (Characteristics of Changes in Water Quality in the Suyoung River During Rainfall Event)

  • 김수현;김정선;강임석
    • 한국물환경학회지
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    • 제35권1호
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    • pp.9-18
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    • 2019
  • Recently, it was realized that a significant portion of pollution from urban areas originates from non-point sources such as construction sites, washoff from impervious surfaces, and sewage input from unsewered areas and combined sewer overflows. Especially, Urban stormwater runoff is one of the most extensive cause of the deterioration of the water quality in streams located in urban area. The objective of this study was to investigate runoff characteristics of non-point pollutants source at the urban area in the Suyeong River. Water quality variations were investigated at two points of Suyeong River during a period of 10 rainfall events. Concentration difference of non-point pollution source appeared big by precedent number of days of no rainfall. In addition, Event mean Concentration (EMCs) that well represents runoff characteristics of storm water during rainfall, was calculated, and runoff pollutants loading was also examined. The probability distribution of EMCs of BOD, COD, TOC, T-N, T-P, and TSS were analyzed and the mean values of observed EMC and the median values of estimated EMCs compared through probability distribution. Other objectives of this study were the characterization of discharge from non-point source, the analysis of the pollutant loads and an establishment of a management plan for non-point source of Suyeong River. Also, It was established that the most important thing for the administration of non-point pollution source is to come up with the solution for the reduction of effluent at the beginning.

하수슬러지를 이용한 Bio-block의 비점오염물질 제거 가능성 평가 (Evaluation of the Feasibility of Eliminating Non-point Source Pollution Using Waste Sewage Sludge Bio-blocks)

  • 한상무;김도형;정병곤
    • 한국물환경학회지
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    • 제37권5호
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    • pp.363-368
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    • 2021
  • On the assessment results of the non-point source pollutant removability of bio-block using waste sewage sludge, at the reactor's initial operation stage, the removal efficiency of COD was slightly unstable. However, after the reactor was stabilized, the COD removal efficiency was higher in the reactor filled with bio-blocks compared to the reactor filled with broken stones. In terms of nitrogen and phosphorus, their removal efficiency was unstable at the initial stage of the reactor operation. This phenomenon was investigated through the bio-block elution experiments. Results indicated that nitrogen and phosphorus were eluted from the bio-blocks affecting their removal at the initial operation. Furthermore, based on elution tests conducted after the dry ashing of the waste sewage sludge, part of the nitrogen and phosphorus was eluted similar to the bio-block elution test results, although considerable amounts of nitrogen and phosphorus were reduced compared to the sludge cake. Prior to the use of the waste sewage sludge bio-blocks as a filter medium to remove non-point source pollutants, a stabilization period of 10 days was required. After the stabilization process, results showed similar characteristics as general aggregates. Moreover, to use the bio-block as a filter medium for the non-point pollutant removal, the filling ratio of 75% was the most suitable as it resulted in the highest nitrogen removal efficiency after the stabilization. The results of this study suggested that waste sewage sludge can be suitably recycled as a mixed raw material for the bio-blocks, with satisfactory application as a filter medium in artificial wetlands, stormwater runoff problems, stream water pollutants to eliminate non-point source pollutants.

팔당 상수원 보호구역내 도로비점오염의 특성 및 저감시설의 적용성 연구 (Characteristics of Roadside Non-point Pollution and Applicability of Reduction Facilities in Paldang Water Source Protection Zone)

  • 조혜진;송미영
    • Ecology and Resilient Infrastructure
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    • 제7권4호
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    • pp.294-299
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    • 2020
  • 본 연구에서는 팔당 상수원 보호구역내 적정 도로비점오염 저감시설의 계획을 위해 대상 도로구간의 현장조사를 통해서 보호구역내 도로의 특성을 파악하고 이에 적용가능한 도로를 선정하고 시설을 시범적용하여 그 유효성을 검증하였다. 팔당 상수원 보호구역은 도로주변 토양의 배수등급이 높아 침투시설을 지양하고 도로사면을 통한 자연적인 오염원 저감방법을 적용하는 것이 적정하다. 앞으로 도로비점저감시설의 계획 및 설계에서 대상도로의 특성에 대한 분석 후 저감계획을 세우는 것이 적정하며 이는 관련 규정 및 설계 기준에도 반영되어야 할 것이다.