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1.
:以Pt/C作电极,石棉作电池隔膜,组装成去除CO2用电池,试验了各种工作条件对电池性能的影响。实验结果证明了电化学方法去除空气中CO2的可行性。 相似文献
2.
James E. Bowie Marvin T. Bond 《Journal of the American Water Resources Association》1977,13(6):1269-1280
ABSTRACT: Many wells produce water that is highly colored by organic substances. Colored water may cause aesthetic, economic, and health problems for the cities using it as a municipal supply. Characterization of water from a number of wells showed that the color causing compounds were hydroxylated aromatic carboxylic acids which were precipitated below pH 4.5 and were almost completely ionized above pH 4.5. Through jar tests, a chemical precipitation-coagulation treatment system was developed. The optimal sequence of chemical addition was alum first, followed by pH adjustment and addition of a polyelectrolyte. Rapid mix tests demonstrated the need for a reaction period after alum and after acid addition, and that the rapid mix time controlled floc size for a given flocculation period. Flocculation tests, varying both the floc time and mean velocity gradient, G, showed that an optimum G exists for each floc time and that the residual color decreased with decreasing values of velocity gradient. 相似文献
3.
Mark A. Snyder Lisa C. Sloan Jason L. Bell 《Journal of the American Water Resources Association》2004,40(3):591-601
ABSTRACT: Using a regional climate model (RegCM2.5), the potential impacts on the climate of California of increasing atmospheric CO2 concentrations were explored from the perspective of the state's 10 hydrologic regions. Relative to preindustrial CO2 conditions (280 ppm), doubled preindustrial CO2 conditions (560 ppm) produced increased temperatures of up to 4°C on an annual average basis and of up to 5°C on a monthly basis. Temperature increases were greatest in the central and northern regions. On a monthly basis, the temperature response was greatest in February, March, and May for nearly all regions. Snow accumulation was significantly decreased in all months and regions, with the greatest reduction occurring in the Sacramento River region. Precipitation results indicate drier winters for all regions, with a large reduction in precipitation from December to April and a smaller decrease from May to November. The result is a wet season that is slightly reduced in length. Findings suggest that the total amount of water in the state will decrease, water needs will increase, and the timing of water availability will be greatly perturbed. 相似文献
4.
Arthur L. Fredeen James T. Randerson N. Michele Holbrook Christopher B. Field 《Journal of the American Water Resources Association》1997,33(5):1033-1039
ABSTRACT: Californian annual grassland on sandstone (moderately fertile) and serpentine (very infertile) soils at the Jasper Ridge Biological Preserve, Stanford, California, were exposed to ambient or elevated (ambient + 36 Pa CO2) atmospheric CO2 in open-top chambers since December 1991. We measured ecosystem evapotranspiration with open gas-exchange systems, and soil moisture with time-domain reflectometry (TDR) over 0–15 cm (serpentine) and 0–30 cm (sandstone) depths, at times of peak above ground physiological activity. Evapotranspiration decreased by 12 to 63 percent under elevated CO2 in three consecutive years in the sandstone ecosystem (p = 0.053, p = 0.162, p = 0.082 in 1992, 1993, and 1994, respectively). In correspondence with decreased evapotranspiration, late-season soil moisture reserves in the sandstone were extended temporally by 10 ± 3 days in 1993 and by 28 ± 11 days in 1994. The effect of elevated CO2 on soil moisture was greater in the drier spring of 1994 (419 mm annual rainfall) than in 1993 (905 mm annual rainfall). In the serpentine ecosystem, evapotranspiration and soil moisture reserves were not clearly affected by elevated CO2. Soil water may be conserved in drought-affected ecosystems exposed to elevated CO2, but the amount of conservation appears to depend on the relative importance of transpiration and soil evaporation in controlling water flux. 相似文献
5.
W. Michael. Aust Russ Lea James D. Gregory 《Journal of the American Water Resources Association》1991,27(1):111-116
ABSTRACT: A palustrine water tupelo (Nyssa aquatica L.)-baldcy-press (Taxodium distichum (L.) Rich.) swamp in southwestern Alabama was subjected to three types of disturbance, including helicopter logging, rubber-tired skidder logging simulation, and helicopter logging followed by an herbicide application. An adjacent undisturbed stand served as a control area. Post-harvest collection of sedimentation data revealed that the herbaceous and woody vegetation regrowth within the helicopter and skidded clearcut areas trapped more sediments than did the control or herbicide treatment areas. Clearcutting, followed by plant regrowth, improved the wet-land's capacity to remove sediments from overbank flow flood waters. 相似文献
6.
Adnan Shindala 《Journal of the American Water Resources Association》1972,8(5):987-998
ABSTRACT. A comprehensive evaluation of current techniques for nutrients, nitrogen and phosphorus, removal from wastewaters was conducted by the author under a research project supported by the Office of Water Resources Research, Department of the Interior. The object of this study was to compile and evaluate, under one cover, the available information on current techniques for removing nutrients from wastewaters with emphasis on type of treatment (physical, chemical, biological, or any combination); economics (capital and operating costs); efficiencies, and applications. Due to space limitations, only a brief summary of this work is presented in this paper. A copy of the completion report may be obtained from the author. 相似文献
7.
Stewart J. Cohen 《Journal of the American Water Resources Association》1987,23(1):91-101
ABSTRACT: Two scenarios of CO2-induced climatic change are used to estimate changes in water use for a number of municipalities in the Great Lakes region of Canada and the United States. Both scenarios, based on General Circulation Models produced by the Goddard Institute for Space Studies (GISS) and Geophysical Fluid Dynamics Lab (GFDL), project warmer temperatures for the region. Using regression models based on monthly potential evapotranspiration for individual cities, it is projected that annual per capita water use will increase by a small amount, which will probably have only a marginal effect on water supplies in the Great Lakes basin. This method could also be used to assess the potential impacts of CO2-induced climatic change on water use by the agriculture and power sectors, as well as the effectiveness of water policy initiatives, such as price changes. More work is needed to project water use during peak periods (warm dry spells), which may occur more frequently in a 2 × CO2 climate in this region. 相似文献
8.
TETA对CO_2的吸收及其动力学参数的推导 总被引:2,自引:0,他引:2
为了提高CO2的吸收量,选用含四个氮原子的三乙烯四胺(简写为TETA)为吸收剂,在常压下,采用搅拌式反应器对TETA吸收CO2进行了研究。得到TETA吸收CO2的最佳温度为308K、最佳浓度为1.0mol/L,并与常用的醇胺吸收剂一乙醇胺(简写为MEA)、二乙醇胺(简写为DEA)、三乙醇胺(简写为TEA)的吸收效果进行比较,实验结果显示:TETA是一种性能优良的CO2吸收剂。同时分析了各吸收剂对二氧化碳的吸收机理;应用化学动力学理论计算了不同温度下TETA吸收CO2反应的级数,速率常数及反应的平均活化能。计算结果表明,在最佳温度308K时,反应的速率常数最大,反应速率最快,反应级数n=1.6,速率常数k′=0.172,平均活化能Ea=132kJ/mol。 相似文献
9.
Molly M. Pohl 《Journal of the American Water Resources Association》2002,38(6):1511-1519
ABSTRACT: Over 76,000 dams have been constructed on American rivers to provide services such as flood protection, water storage, hydroelectric power, and navigation. Although most dams continue to provide sufficient benefits to retain the structure, dam removal is becoming increasingly common. This study involved the construction of a dam removal database to analyze spatial and temporal trends in dam removal. The data included information on 417 cases of dismantled American dams, 153 with known rationales for removal. Database analysis indicated that the leading purposes for dismantling structures are safety concerns and interest in environmental restoration. There is substantial geographic variability in dam removal rationales, with California leading in razing dams for environmental purposes, and Wisconsin leading in economic and safety rationales. States with substantial removals tend to have programs that support and fund dam razing. Although removals for safety reasons have been increasing steadily in the past three decades, environmental removals made a rather dramatic and sudden entry into the dam removal arena in the 1990s. Analysis of spatial and temporal trends in dam razing are of particular significance given the likely increase in dam removals in the 21st Century. 相似文献
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大气CO2浓度不断增加将以两种方式影响作物的代谢、生长发育和产量的形成:一是通过温室效应“加热”气候,改变降水类型,进而影响作物;二是浓度变化本身对作物生理过程的影响。介绍了国内外近年来在与CO2浓度有关的作物生理实验方面取得的进展及其主要结果。 相似文献
12.
二氧化碳捕集技术发展动态研究 总被引:3,自引:0,他引:3
介绍了近年来新兴的二氧化碳捕集技术路线和国内外的有关研究项目。通过研究由清洁发展机制延伸出来的碳交易及其市场表明,在未来的几十年中,碳交易将成为最大的贸易商品,并且能够减少环境污染和产生较高的利益。 相似文献
13.
Shie-Yui Liong Donn G. DeCoursey 《Journal of the American Water Resources Association》1982,18(2):307-310
ABSTRACT: The need for a quick means to predict the subsurface flow into a stream caused the authors to take a different approach to the problem. Dimensional analysis was applied to deduce a functional relationship between the dependent and independent variables. This paper lays the ground work for the development of prediction equations for a phreatic aquifer in response to infiltration. 相似文献
14.
温室气体CO2的减排问题已经引起了国际社会的极大关注。火电行业是CO2排放量的主体。燃煤电厂实施碳减排和碳零排放是走向清洁能源必由之路。目前,燃煤电厂实施CO2的减排主要是从常规燃煤电厂烟道气分离CO2,其中,电厂CO2捕集技术路线主要包括燃烧后脱碳、燃烧前脱碳、富氧燃烧以及化学链燃烧技术。 相似文献
15.
大多数天然气藏CO2含量为10%~98%,CO2在不同的温度、压力条件下腐蚀极其严重。文章主要针对高含CO2天然气运输管道腐蚀的问题,开展缓蚀剂的筛选,重点开展CO2腐蚀规律研究与实验,评价环境温度、CO2分压、流动速度对腐蚀规律的影响,明确缓蚀剂的影响因素,结合管材的材质,优选评价不同类型的缓蚀剂,缓蚀效率分别为90.53%和92.64%,在管道凝液介质的气相及液相中都有较高的缓蚀效率。通过设计现场加药工艺及制度,监测评价缓蚀剂缓释效果和腐蚀情况,可防止管道运输过程中CO2腐蚀的侵害,长输管线内腐蚀控制良好。 相似文献
16.
Brain M. Reich Kenneth G. Renard 《Journal of the American Water Resources Association》1981,17(1):67-74
ABSTRACT: Flood frequency analyses are frequently being made using widely available computer programs. Serious errors can result from blind acceptance of such results. Visual interpretation of observed flood series can be used for evaluation on frequency paper with compatible scales. Such frequency papers are presented in the paper. In ephemeral streams, more infrequent floods may constitute a separate set from the more frequent floods because (a) runoff producing storms cover only a portion of the contributing area, (b) transmission losses in the normally dry streambed may reduce the peak flow, and (c) some runoff may be stored in stock water ponds which therefore leads to partial area runoff. The Cunnane plotting position used in this paper is superior to the more widely used Weibull equation, having a mathematically sound basis for locating observed floods on an assumed probability. 相似文献
17.
G. R. Soltani 《Journal of the American Water Resources Association》1977,13(1):137-142
ABSTRACT: The possibility of increasing the water supply for irrigation through adoption of more efficient water-application techniques as an alternative to new irrigation projects was studied in an irrigated region of Iran. Excessive water application at the farm level ranks high among the causes of water shortages in the selected region. An empirical analysis of the effect of water-saving technology on the farm operator's net return was made choosing two farms in the region as a case study. The problems facing these farms are common to most farms throughout the country. The results of the budgeting analysis of the selected farms indicated that an improvement in irrigation technique can result in the expansion of water supply and higher marginal value product for water. Comparing the costs of irrigation systems with the net returns resulting from the higher efficiency showed that such an investment is economically feasible. 相似文献
18.
Stephen J. Burges 《Journal of the American Water Resources Association》1979,15(1):227-243
ABSTRACT: Components contributing to uncertainty in the location of the flood plain fringe of a mapped flood plain are identified and examined to determine their relative importance. First-order uncertainty analysis is used to provide a procedure for quantifying the magnitude of uncertainty in the location of the flood plain fringe. Application of the procedure indicated that one standard deviation of uncertainty in flood plain inundation width was about one third of the mean computed inundation width for several flood population-flood geometry combinations. Suggested mapping criteria, which directly incorporate uncertainty estimates, are given. While these criteria are more suitable for use in developing areas than in flood plains that have had extensive development, the analysis procedure can be used to accommodate property owners who challenge the validity of estimated flood fringe boundaries. Use of uncertainty analysis in flood plain mapping should enhance the credibility of the final plan. 相似文献
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Swati Mookherji Gregory W. McCarty Jonathan T. Angier 《Journal of the American Water Resources Association》2003,39(2):381-387
ABSTRACT: Dissolved gas analysis permits direct detection of ground water denitrification, a technique we used in this study to assess the fate of nitrate in a riparian wetland. Dissolved argon (Ar) and dinitrogen (N2) were measured in transects of nested piezometers installed at different depths within upwelling regions of a riparian wetland. The method uses the Ar content in the water as a natural inert tracer for assessing background content of N2 from the previous air/water equilibrium. Within the wetland under study, anoxic to suboxic ground water became more oxic in piezometers close to the aquifer layer, indicating upwelling of oxic ground water. Assessment of loss of nitrate and Ar in ground water within an upwelling zone indicated that shallow piezometers had significant N2 loss through degassing. Most of the measured nitrate‐nitrogen (NO3?‐N) loss of 205 μM in a piezometer nest could be accounted for by total N2‐N produced (169 μM N), calculated from changes in dissolved N2 and estimated N2 degassed. Degassing due to methane (CH4) production was also detected in some shallow piezometers within nests. This technique for analysis of dissolved gases in ground water can be applied to detect small changes in N gas concentration and aids in assessing the fate of nitrate along a ground water flow path. 相似文献