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111.
Fish have evolved traits and life history characteristics that enable them to survive, exploit and depend on the flow regime of rivers, particularly the timing and predictability of flows for spawning and rearing their young. It is unclear to what degree pulsed flows from hydropower facilities and other environmental variables influence migratory behaviours. We used Dual Frequency Identification Sonar in the Michipicoten River, Canada, to address the relationship between fish migration and environmental factors with a focus on flow magnitude and fluctuation. In both 2007 and 2009, the peak of the Chinook (Oncorhynchus tshawytscha) and pink salmon (Oncorhynchus gorbuscha) migration occurred on 8 September. Mean water temperature on this date was 18 °C and precipitously dropped afterwards. The photoperiod was roughly 12‐h long with sunrise at 700 h and sunset at 2000 h. Most fishes moved upstream during the hours of darkness between 2000 and 600 h. The lowest counts of fish occurred from noon to just before sunset, whereas highest counts commonly occurred from 1 to 2 h after sunset. Fish moved upstream during all magnitudes of flow; however, there was a slight preference for larger flows in 2007 but not in 2009. Changes in flow magnitude occurred both during the day and night, with flows typically increasing during the day to meet electrical demand and decreasing at night. Most fishes moved upstream during periods of little to no change in flow. High flows and changing flows may deter salmon from moving up the Michipicoten River but not likely in a significant manner to cause energetic stress or harm. Other adverse effects of pulsed flows, however, must still be considered for spawning, hatching and rearing success. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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113.
The objectives of this study are to provide detailed information about green roof performance in the Mediterranean climate (retained volume, peak flow reduction, runoff delay) and to identify a suitable modelling approach for describing the associated hydrologic response. Data collected during a 13-month monitoring campaign and a seasonal monitoring campaign (September-December 2008) at the green roof experimental site of the University of Genova (Italy) are presented together with results obtained in quantifying the green roof hydrologic performance. In order to examine the green roof hydrologic response, the SWMS_2D model, that solves the Richards' equation for two-dimensional saturated-unsaturated water flow, has been implemented. Modelling results confirm the suitability of the SWMS_2D model to properly describe the hydrologic response of the green roofs. The model adequately reproduces the hydrographs; furthermore, the predicted soil water content profile generally matches the observed values along a vertical profile where measurements are available. 相似文献
114.
Barredo-Damas S Alcaina-Miranda MI Gemma M Iborra-Clar MI Mendoza-Roca JA 《Water science and technology》2011,64(11):2169-2176
This work studies the performance of three commercial ceramic ultrafiltration membranes (ZrO(2)-TiO(2)) treating raw effluent from a textile industry. The effect of crossflow velocity at 3, 4 and 5 m s(-1) as well as membrane characteristics, such as molecular weight cut-off (30, 50 and 150 kDa), on process performance were studied. Experiments were carried out in concentration mode in order to observe the effect of volume reduction factor simultaneously. Results showed a combined influence of both crossflow velocity and molecular weight cut-off on flux performance. TOC and COD removals up to 70% and 84% respectively were reached. On the other hand, almost complete color (>97%) and turbidity (>99%) removals were achieved for all the membranes and operating conditions. 相似文献
115.
A new approach using input-output techniques is proposed for the analysis of urban stormwater pollution caused by urban land development. The input-output model provides projections of sectoral outputs within an urban region. By defining land as an input to production, these output projections may be translated into projections of commercial and industrial land development. Furthermore, the closed version of the input-output model is used to project residential land development as a function of projected wage income. The pollutant generation in urban stormwater is related to the quantity of each category of land development by a pollutant coefficient matrix. Thus, the model can be used to predict the impact of various economic growth scenarios on pollution loadings in runoff water. This will help planners in assessing the environmental costs of various scenarios, and in preparing for remedial actions. A numerical example is provided to illustrate the applications of the model. 相似文献
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117.
Yu. I. Frishter O. A. Kogodovskii 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1995,29(12):694-706
1. | When constructing earth dams the inclusion of foreign members in the form of reinforced-concrete galleries, shafts, etc., in the body of the structure is impermissible. It is also desirable to eliminate the construction of a grouting gallery under the dam. The foundation should be grouted either before or after constructing the dam. |
2. | Installation of monitoring and measuring equipment for observations during operation must be done after completing construction of the dam. Installation of MME during construction leads to its complete disturbance, holds up the rate of filling, and affects the quality of the works. |
118.
Udvarhelyi IS Relman AS Binder GM Spence RK Kennedy EM Grossman JH Termeer HA Raines LJ Marincola E Pyle TO 《Harvard business review》1994,72(5):45-7, 50, 52 passim
In "Making Competition in Health Care Work" (July-August 1994), Elizabeth Olmsted Teisberg, Michael E. Porter, and Gregory B. Brown ask a question that has been absent from the national debate on health care reform: How can the United States achieve sustained cost reductions while at the same time maintaining quality of care? The authors argue that innovation driven by rigorous competition is the key to successful reform. A lasting cure for health care in the United States should include four basic elements: corrected incentives to spur productive competition, universal insurance to secure economic efficiency, relevant information to ensure meaningful choice, and innovation to guarantee dynamic improvement. In this issue's Perspectives section, eleven experts examine the current state of the health care system and offer their views on the shape that reform should take. Some excerpts: "On the road to innovation, let us not forget to develop the tools that allow physicians, payers, and patients to make better decisions." I. Steven Udvarhelyi; "Health care is not a product or service that can be standardized, packaged, marketed, or adequately judged by consumers according to quality and price." Arnold S. Relman; "Just as antitrust laws are the wise restraints that make competition free in other sectors of the economy, so the right kind of managed competition can work well in health care." Edward M. Kennedy "Biomedical research should be considered primarily an investment in the national economic well-being with additional humanitarian benefits." Elizabeth Marincola. 相似文献
119.
Sharma A Kesner IF Coleman KL Greyser SA Burlingame H Galford R Rubin GS 《Harvard business review》1997,75(1):18-20, 22-3, 26-8 passim
The news that one of the company's senior managers is leaving comes as a complete surprise to Paul Simmonds, CEO of Kinsington Textiles, Inc. Ned Carpenter, KTI's vice president of operations for three years, writes in his resignation letter than he is leaving for a better opportunity. Simmonds soon learns that Carpenter's new job is at Daltex, one of KTI's main rivals in the intensely competitive carpet industry. Hiring Carpenter had helped Simmonds establish his reputation as a topnotch manager. Carpenter came to KTI with lots of ideas and put his enthusiasm to good use. Three years into a five-year change program, Carpenter had turned KTI's operations from one of the worst in the industry to one of the best. He also had helped develop and plan the upcoming launch of a new fiber coating--KTI's first breakthrough in years. In this fictitious case study, Simmonds, along with the company's counsel and vice president of human resources, must figure out how much and what sort of damage control they need. What are they going to tell the company's employees and the media? Should they immediately replace Carpenter with John Brady, the second-in-command of operations? What if Carpenter is taking KTI employees--and strategic information--with him to Daltex? Should Simmonds ask all his managers to sign noncompete agreements-something Carpenter was never asked to do? Should KTI sue Carpenter? Five experts offer advice about communicating with KTI's employees, the media, and Carpenter himself, and about protecting the company's confidential information. 相似文献
120.
A. A. Ravkin I. I. Shekhtman 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1993,27(11):627-632
1. | The prefabricated cutoff wall as one of the economically justified designs can be regarded as the main watertight element of an earth dam. |
2. | The cutoff wall can be made from precast asphaltic concrete and concrete blocks and combined — from both joined together on asphalt mastic. An analysis of the stress-strain state showed that each of these walls has a sufficient margin of deformability. |
3. | The cutoff wall of precast concrete blocks, eliminating the use of asphalt for its construction and having a practically unlimited margin of deformability, can be of interest to designers and builders. |