• Computers and Concrete
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• 제29권1호
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• pp.47-57
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• 2022

The increase in waste tires has brought serious environmental problems. Using waste tires rubber particles as aggregate in concrete can reduce pollution and decrease the usage of natural aggregate. The paper describes an investigation on flexural bearing capacity of self-compacting concrete (SCC) pavement slabs containing crumb rubber. Cyclic loading tests with different stress ratios and loading frequencies are carried out on SCC pavement slabs containing crumb rubber. Based on Paris Law and test data, the fatigue life of SCC pavement slab containing crumb rubber is discussed, and a revised mathematical model is established to predict the fatigue life of SCC pavement slab containing crumb rubber. The model applies to different stress ratios and loading frequencies. The fatigue life of SCC pavement slab containing crumb rubber is affected by the stress ratio and loading frequency. The fatigue life increases with the increase of stress ratio and loading frequency. Real-time acoustic emission (AE) signals in the SCC pavement slab containing crumb rubber under cyclic loading are measured, and the characteristics of crack propagation in the SCC pavement slab containing crumb rubber under different stress ratios and loading frequencies are compared. The AE signals provide abundant information of fracture process zone and crack propagation. The variation of AE ringing count, energy and b-value show that the fracture process of SCC pavement slab containing crumb rubber is divided into three stages.

• 한국물환경학회지
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• 제27권5호
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• pp.572-579
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• 2011

We have examined the runoff characteristics of nonpoint source (NPS) in fields. Two monitoring sites were equipped with an automatic velocity meter and water sampler. Monitoring was conducted at fields 1 and field 2 during the rainfall event. Ten rainfall-runoff events were monitored and analyzed during the study period. The results show that runoff occurred if daily rainfall and intensity were higher than 40 mm and 1.6 mm/hr except a few extreme rainfall events with very high intensity. Runoff of field 1 was approximately twice of that of field 2. Event mean concentrations (EMC) and pollution load of analyzed water quality indices were also higher in field 2 than in field 1. Especially, TN load from field 2 was $75.4 mg/m^2$ and was about 5 times higher than that from field 1. Analysis of Pearson correlation coefficient of water quality parameter indicates that besides of TN all items in fields 1 have tight relationship respectively (p < 0.01). But those of fields 2 have a significant (p < 0.05). Estimating units loading of NPS, we suggested that variable such as soil texture, rainfall amount and intensity and slope were needed to be considered from agricultural landuses. The results of this study can be used as a basic data in the development and implementation of total maximum daily loads (TMDL) in Korea.

• 한국농공학회논문집
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• 제52권5호
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• pp.77-86
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• 2010

Hydrologic Simulation Program-Fortran (HSPF) coupled with PEST which is optimization program was calibrated and validated at Bochung watershed by using monitoring data of water quantities and nutrient loading. Although the calibrated data were limited, model parameters of each land use type were optimized and coefficient of determinations were ranged from 0.94 to 0.99 for runoff, from 0.89 to 1.00 for TN loading, and from 0.92 to 1.00 for TP loading. The optimized hydrological parameters indicated that the forested land could retain rainfall within soil layer with high soil layer depth and infiltration rate compared with other land use type. Hydrological characteristics of paddy rice field are low infiltration rate and coefficient of roughness. The calibrated parameters related to nutrient loading indicated generation of nutrient pollution from agricultural area including upland and paddy rice field higher than other land use type resulting from fertilizer application. Overall PEST program is useful tool to calibrate HSPF automatically without consuming time and efforts.

• 한국물환경학회지
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• 제20권6호
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• pp.657-663
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• 2004

The aims of this study are the characterization of runoff from nonpoint source, the analysis of the pollutant loads and an establishment of a management plan for nonpoint source of Okcheon. For this purpose the basin of the stream So-okcheon was selected to the investigated. During the period from May 29 to July 21 in 2003, the water automatic sampler system has been installed in Okkagkyo and parameters such as SS, COD, TOC, TP and TN were analyzed. The pollutants of nonpoint source seem to be washed out along the stream water in the beginning of rainfall, remain in water and cause the stream pollution. The runoffs during heavy rainfall, especially, much higher concentration of SS than those during dry period. With respect to the annual loading of pollutants of the nonpoint source, the COD was 124 ton/yr, TOC 396 ton/yr, TN 1,429 ton/yr and TP 4.2 ton/yr in the year 2002. With respect to the pollutants loading of the nonpoint source, the COD was 375 ton/yr(95% of the total COD loading of 394 ton/yr), TOC 844 ton/yr(96% of the tatal TOC loading of 876 ton/yr), TN 1,985 ton/yr(96% of the total TN loading of 2,062 ton/yr) and TP 37.1 ton/yr(92% of the total TP loading of 40.3 ton/yr) in the year 2003.

• 한국환경과학회지
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• 제13권11호
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• pp.1001-1007
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• 2004

The rapid industrialization and urbanization in Osaka Bay have produced many serious water pollution problems since the 1960s. A symbolic phenomenon is algae bloom (red tide), which occurred 53 times in 1976. The special law was enacted in 1973 and a number of administrative steps were taken, such as cutting COD loading, reductions in phosphorus (P) and restriction of land reclamation. As a result, the pollution of Osaka Bay has gradually been reduced, and the environment has been improved to some extent. In this study, to analyze the relations between water qualities as well as a social, economic activity by the coastal zone, the water quality data in Osaka Bay of 70 years past since 1921 were collected. Data such as population, livestock, fertilizer, industrial product etc. were also collected for estimating nutrients flowing into bay from land. It was found that the water quality was changed of a similar trend of estimated nutrients load, with delay of about four or five years.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.12-19
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• 2000

The increasing use of vehicles is causing air-pollution problems. Diesel vehicles are preferred to gasoline vehicles, because the diesel vehicles are superior to gasoline vehicles in terms of fuel consumption, durability, power and efficiency. But the emission reduction technologies for diesel vehicle are not developed well like those for gasoline vehicles. Moreover, the NOx and smoke emitted from diesel vehicle are recognized as a main source of the air-pollution in the urban areas. The emission reduction devices have been installed for each of the emission gas components. Using plasma(i.e. electrical energy)only, the emission gas was found to be reduced. The present paper investigate the effects of a low temperature plasma device in engine performance as well as in emission reduction with the change of the applied voltage and the loading rate of the engine.

• 환경위생공학
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• 제24권1호
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• pp.1-12
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• 2009

The various environmental problems that we face on today are basically about environmental quality. Since early 1960s affluent material was produced because of remarkable economic growth by many cooperations. However, for the lack of environmental policy, environmental pollutions has been serious. The central government should transfer the producing and consuming structure to environmental affinity through the regulations for developing Korea as a model of environmental nation which takes an active part in global environmental programme and in which the environment and economy are well harmonized. Moreover, the central government should take the lead in prevention of environmental pollution through the direct policies such as strengthening the discharge limit or setting up environmental basic institutions by securing budget for conserving environment. This thesis emphasize on the public institution among many environmental basic institutions for environmental anti-pollution project. It will find the problems with running those institutions, and will suggest the preview of improvement. Also, it is necessary to investigate of variation trend for inflow and pollutant loading to environmental infrastructure as increased of the diffusion rate as established and maintenance of sewer system. The purpose of this study is to investigate for inflow and pollutant loading to environmental infrastructure, and also to provide the method of efficiently maintenance and management. The results obtained were summarized as follows; 1. Survey of actual condition on operation and management of environmental infrastructure was evaluated the propriety of treatment process and problem of plant management. 2. Analysis of pollutant loading contribution for river system of environmental infrastructure with data analysis of water quality measuring network. 3. To investigate on case study for efficiently maintenance and management of environmental infrastructure. The result on this study was provide the method of efficiently maintenance and management with survey for establish and repair of sewer system and survey of actual condition on operation and management of environmental infrastructure in the water area of discharge to Geum River System. Application as guideline for establish and management of environmental infrastructure, and management of Geum River System. Also, application for preliminary data for fulfill-assess of total effluent regulation of water pollution.

• Ocean Science Journal
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• 제40권1호
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• pp.1-10
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• 2005

Variations in species diversity and abundance of polychaete taxocenes that occurred in 1980-1989 under different contamination levels of bottom sediments were studied in three areas of Peter the Great Bay. The most polluted area was shown to be the Golden Horn Inlet where contaminant contents in the bottom sediments exceed the threshold values of negative biota alterations. Amursky Bay is characterized by a moderate level of contamination, while Ussuriysky Bay has the lowest level of contamination. Pollutant contents vary considerably within the same areas and their separate patches are polluted differently. An integral index characterizing the contamination of bottom sediments is proposed. This index is an average grade of the rank value of contaminant contents in sediments. The index was used to compare the contamination level and data on polychaete species diversity and abundance. The highest species diversity of polychaetes is found in the least affected zones. Monotonous decrease of the species number, as well as decrease in the indices of diversity and evenness, is correlated with pollution level increases. Significant growth of the average polychaete biomass and polychaete density is observed in the case of an increase of contamination from low to moderate levels. Conversely, the biomass and abundance of polychaetes decline following an increase in contamination.

• Membrane and Water Treatment
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• 제10권6호
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• pp.451-460
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• 2019

Thin film composite membranes incorporated with nano-sized hydrophilic zeolite -A were successfully prepared via interfacial polymerization (IP) on porous blend PES/PAN support for water desalination. The thin film nanocomposite membranes were characterized by SEM, contact angle and performance test with 7000 ppm NaCl solution at 7bar. The results showed that the optimum zeolite loading amount was determined to be 0.1wt% with permeate flux 29LMH.NaCl rejection was improved from 69% to 92% compared to the pristine polyamide membrane where the modified PA surface was more selective than that of the pristine PA. In addition, there was no significant change in the permeate flux of the thin film nanocomposite membrane compared with that of the pristine PA in spite of the formation of the dense polyamide layer. The stability of the polyamide layer was investigated for 15 days and the optimized membrane presented the highest durability and stability.

• 한국환경보건학회지
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• 제22권1호
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• pp.5-11
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• 1996

The more accurate estimation of the pollutant loadings from nonpoint source is needed to evaluate water quality of water resources such as river and reservoir. Therefore this study was performed to grasp the scale and characteristics of pollutant. In this study, STORM model was applied to I-cheon district to estimate runoff and pollutant loading of SS, BOD, T-N and $PO_4-P$. The results estimated by STORM model were fitted well to surveyed water quality in flow, SS and BOD. The annual loadings were estimated to be 36,463 kg/$km^3$/yr of SS, 8,090 kg/$km^3$/yr of BOD, 4,435 kg/$km^3$/yr of T-N and 358 kg/$km^3$/yr of $PO_4-P$. It was also found that the monthly pollutant loadings of SS, BOD, $PO_4-P$ were greatest in May and T-N in April.