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931.
Jae H. Ryu Richard N. Palmer Sangman Jeong Joo Heon Lee Young‐Oh Kim 《Journal of the American Water Resources Association》2009,45(2):485-499
Abstract: A decision support system for sustainable water resources management in a water conflict resolution framework is developed to identify and evaluate a range of acceptable alternatives for the Geum River Basin in Korea and to facilitate strategies that will result in sustainable water resource management. Working with stakeholders in a “shared vision modeling” framework, sustainable management strategies are created to illustrate system tradeoffs as well as long‐term system planning. A multi‐criterion decision‐making (MCDM) approach using subjective scales is utilized to evaluate the complex water resource allocation and management tradeoffs between stakeholders and system objectives. The procedures used in this study include the development of a “shared vision model,” a simulated decision‐making support system (as a tool for sustainable water management strategies associated with water conflicts, management options, and planning criteria), and the application of MCDM techniques for evaluating alternatives provided by the model. The research results demonstrate the utility of the sustainable water resource management model in aid of MCDM techniques in facilitating flexibility during initial stages of alternative identification and evaluation in a basin suffering from severe water conflicts. 相似文献
932.
Properties of lightweight aggregate concrete prepared with PVC granules derived from scraped PVC pipes 总被引:1,自引:0,他引:1
This paper aims to investigate the fresh and hardened properties of lightweight aggregate concretes that are prepared with the use of recycled plastic waste sourced from scraped PVC pipes to replace river sand as fine aggregates. A number of laboratory prepared concrete mixes were tested, in which river sand was partially replaced by PVC plastic waste granules in percentages of 0%, 5%, 15%, 30% and 45% by volume. Two major findings are identified. The positive side shows that the concrete prepared with a partial replacement by PVC was lighter (lower density), was more ductile (greater Poisson's ratios and reduced modulus of elasticity), and had lower drying shrinkage and higher resistance to chloride ion penetration. The negative side reveals that the workability, compressive strength and tensile splitting strength of the concretes were reduced. The results gathered would form a part of useful information for recycling PVC plastic waste in lightweight concrete mixes. 相似文献
933.
This article is intended to provide background information on leachate management in closed landfill sites based on a comparison
of two landfill sites and the identification of leachate characteristics depending on the final cover and the season. Site
S is older and has no final cover, while site J is younger and has final capping. The results of leachate analysis from the
two landfills show that the biological oxygen demand to chemical oxygen demand ratio decreases below 0.1 to the range 0.05–0.07
for site S, whereas the ratio at site J was in the range 0.08–0.55. The inorganic nitrogen concentration was in the range
169.9–386.1 mg/l with an average of 265.2 mg/l at site S. Ammonia nitrogen accounted for 98.9% of the total nitrogen. The
absence of a final cover on closed landfill sites may contribute to the stabilization of such landfills due to flushing. The
nitrogen content at landfill S dropped in the summer, whereas it decreased in the fall at site J. A higher fluctuation in
the pollutant levels of organic matters and nitrogen at the younger landfill site was observed, compared to the older site,
even though the younger site had final capping. Therefore, intensive leachate management should be arranged at the early stages
after closing for proper treatment. Specifically, nitrogen management of leachate is a critical factor in treatment operations. 相似文献
934.
Jeong-Hun Kim Yong-Chil Seo Deepak Pudasainee Sang-Hyeob Lee Sung-Jin Cho Ha-Na Jang Ju-Myon Park Geum-Ju Song Kyu-Shik Park 《Journal of Material Cycles and Waste Management》2009,11(3):183-190
The development of regulations patterned after the United States’ requirement for maximum achievable control technology (MACT)
to control hazardous air pollutants from major industrial sources in Korea is in progress. Current management practices and
installed air pollution control devices were surveyed; emission tests and continuous emission data collected from facilities
under operation were assessed considering other MACT requirements such as reporting, report keeping requirements. Emission
sampling and air pollutant analysis were carried out at representative hazardous waste incinerators installed with wet-type
and dry-type air pollution control devices. Korean and United States Environmental Protection Agency methods were used for
sampling and analysis. The major heavy metals emitted were Zn, Ni, Pb, and Cr. The heavy metal removal efficiency of existing
air pollution control devices was greater than 99%. The average mercury removal efficiency was more than 30%. Toluene; m,p-xylene; o-xylene; benzene; dichloromethane; styrene; ethylbenzene; 1,3-dichlorobenzene; and 1,2,4-trimethylbenzene were the major volatile
organic compounds emitted. The emissions from field tests were compared, reviewed, and analyzed with respect to MACT regulations
to check applicability. Finally, draft guidelines were suggested for effective hazardous air pollutant management in Korea. 相似文献
935.
Ji-Hoon Jeong Byung-Taek Oh Jai-Young Lee 《Journal of Material Cycles and Waste Management》2009,11(3):208-213
Most sludge has historically been disposed of in landfills and by ocean dumping but, because of its heavy metal content, this
will be totally banned in Korea starting in 2012, based on the London Dumping Convention. Therefore, treatment and disposal
methods that are environmentally friendlily are urgently required. The recycling of sewage sludge is a good treatment method
for solving sludge problems in an environmentally friendly way. In this study, physical and environmental tests were conducted
to evaluate the feasibility of using the by-products of thermal hydrolysis of sewage sludge as barrier layer materials in
the final cover systems for landfills. In addition, testing methods for freezing-thawing (KS F 2332) and wetting-drying (KS
F 2330) cycles were conducted to assess the effects of cold and hot soil climates starting from pavement. These tests yielded
positive results for alternative materials for the barrier layer in a final cover system for a landfill. 相似文献
936.
Sujeeva Setunge Natalie Nguyen Brendan Lee Alexander Louise Dutton 《Water, Air, & Soil Pollution: Focus》2009,9(5-6):381-391
Concrete is usually the preferred material for construction of structures in contact with water during their service life. Early age exposure to water is beneficial for curing of concrete structures. However, the pollution of water from freshly cast concrete in contact with water has not been investigated in detail. A significant increase in the alkalinity has recently been observed in a stream in contact with freshly installed concrete culverts. High alkalinity has caused distress to fresh water fish in the stream. A preliminary laboratory study was commenced to explore the effect of leaching of alkali into water from freshly placed concrete. Freshly cast concrete specimens were exposed to fresh water, covering a range of conditions observed in the field such as volume of concrete/volume of water, age of exposure and cement content. Analysis of the results indicated that early age contact with fresh concrete can lead to an increase in the pH levels of water up to 11, similar to the levels of pH observed in pore water inside freshly cast concrete. It was noted that until an age of 4 days from casting of concrete, the age of exposure does not significantly affect the changes in the peak pH levels of water. Continuous monitoring of water in contact with concrete also indicated that the pH levels diminish with time, which is attributed to the possible reaction of calcium hydroxide with atmospheric carbon. The paper will present the experimental study, the results, analysis and outcomes as well as planning of a more comprehensive study to observe possible ways of reducing the leaching of alkali from freshly placed concrete. 相似文献
937.
Seong Kon Lee Gento Mogi Jong Wook Kim 《Journal of Loss Prevention in the Process Industries》2009,22(6):915-920
To provide national energy security in the 21st century, establishing a long-term strategic energy technology development is essential through selection and specialization. We established a strategic energy technology roadmap (ETRM) taking economic spin-offs, commercial potential, inner capacity, and technical spin-off into account. In this research, we suggest an integrated multi-criteria decision making (MCDM) approach, which is composed of more than two criteria as the assessment of the optimal alternatives and solutions in the real world with the fuzzy theory and analytic hierarchy process (AHP), to prioritize the weights of energy technologies of ETRM as we allocate R&D budget using a fuzzy analytic hierarchy process. Building technology is the most preferred technology in the sector of energy technologies against high oil prices. And the coal technology and transportation technology follows and take the 2nd and 3rd place with the fuzzy AHP approach. 相似文献
938.
Alastair Smith Christopher James Richard Jones Paul Langston Edward Lester John Drury 《Safety Science》2009,47(3):395-404
This paper highlights the growing need for a realistic crowd simulation in the design of large venues such as concert halls and stadia. A discrete element method (DEM) technique for modelling crowd dynamics has been developed that represents each person within the model as 3 overlapping circles, a position, orientation and velocity in 2D. Contact forces between elements are included in the model as well as psychological forces, motive forces and moments. The motion of each person is then modelled in a Newtonian manner with a numerical integration time-stepping scheme. The model has been shown previously to work well in predicting egress. In this paper the predicted model behaviour is compared to actual video footage shot at various locations around University Park Campus, Nottingham. It did not match well to the video footage when people are moving towards each other, as in cases of contra-flow on a walkway. In order to improve the model, a general algorithm for ‘avoidance’ was included which appeared to make the model significantly more realistic in these cases. The paper also shows areas for further potential development, such as incorporating people into associative groups such as family or friends. 相似文献
939.
The basis of the manSievert as a unit for collective radiation dose is discussed and previous recommendations are considered for how much should be spent to avert a collective dose of 1 manSv. New calculations are given using the J-value method. It is shown that the value to be assigned to averting a manSievert depends on the duration of averted exposure as well as on the net discount rate and the loan rate thought to be appropriate. Different figures will result depending on whether the exposed group consists of workers or the general public. The variation with dose duration is so large that it is not possible to recommend a single figure for the value of a manSievert. Instead, tables are given at two conservative, loan and net discount rates for the value of a manSievert as a function of exposure time. The base data for the J-value method need to be updated annually, and this means that the values given in the tables will increase over time as people live longer and become richer. 相似文献
940.
Yuxin Wu Roelof Versteeg Lee Slater Douglas LaBrecque 《Journal of contaminant hydrology》2009,106(3-4):131-143
Calcium carbonate is a secondary mineral precipitate influencing zero valent iron (ZVI) barrier reactivity and hydraulic performance. We conducted column experiments to investigate electrical signatures resulting from concurrent CaCO3 and iron oxides precipitation under simulated field geochemical conditions. We identified CaCO3 as a major mineral phase throughout the columns, with magnetite present primarily close to the influent based on XRD analysis. Electrical measurements revealed decreases in conductivity and polarization of both columns, suggesting that electrically insulating CaCO3 dominates the electrical response despite the presence of electrically conductive iron oxides. SEM/EDX imaging suggests that the electrical signal reflects the geometrical arrangement of the mineral phases. CaCO3 forms insulating films on ZVI/magnetite surfaces, restricting charge transfer between the pore electrolyte and ZVI particles, as well as across interconnected ZVI particles. As surface reactivity also depends on the ability of the surface to engage in redox reactions via charge transfer, electrical measurements may provide a minimally invasive technology for monitoring reactivity loss due to CaCO3 precipitation. Comparison between laboratory and field data shows consistent changes in electrical signatures due to iron corrosion and secondary mineral precipitation. 相似文献