Microstructure and Stress Differences in Shearing Flows
Steady shearing flows of highly inelastic particles are simulated using rigid and slightly deformable sphere models. Large first normal stress differences in small systems are observed,...
Computer Simulations of Rapid Granular Flows Interacting with a Flat, Frictional Boundary
This paper compares the results of numerical simulations for the rapid, steady flow of identical spheres colliding with a flat frictional boundary with the recent predictions of Jenkins...
Interparticle Sliding and Rolling
Numerical experiments are done with a continuum plasticity program in order to study the initiation and evolution of shear bands. Many elements are used in order to resolve families of...
Marina Refuse and Recycling Facilities
Because of widespread concern regarding the impacts of plastic refuse on marine life, forty-one nations are now party to a treaty which prohibits the disposal of plastics at sea, restricts...
Cleaning North America's Beaches?Volunteers Across America Monitor the Quality of Our Coasts
The Center for Marine Conservation (CMC) has established a National Marine Debris Database to involve citizens in the collection of standardized information on marine debris. A comparison...
Evolution (1980-1990) of Ammonia and Dissolved Oxygen in Guanabara Bay, RJ, Brazil
The UFRJ is located on an island of Guanabara Bay and the Institute of Biology has been developing systematic studies on the bay. A synthesis of these studies and their different methodologies...
Implementation of Vertical Landfill Expansion
Montgomery County, Maryland, proposed to implement a vertical expansion or 'piggyback' design for the County's municipal solid waste landfill. The...
Who is Taking Out the Garbage?
Due to the shortage of landfill space and the increasing amount of waste being generated, current waste disposal techniques should be studied and revised. New methods should be implemented...
Environmental Impacts of Drought in the Tennessee Valley
Beginning in June 1984, the Tennessee Valley region entered the most severe, extended period of drought since record keeping began in 1890. The historical annual average rainfall across...
The State Water Board's New Monitoring Requirements
In coordination with Department of Health Services' (DHS) efforts to gain 'State Authorization' to administer the federal hazardous waste management...
A Demonstration of Strobe Lights to Repel Fish
An EPRI review (EPRI, 1986) of fish protection systems for hydroelectric facilities identified strobe lights as a potential behavioral system to minimize fish entrainment. In 1988, EPRI...
Review of Mitigation Methods for Fish Passage, Instream Flows, and Water Quality
Current environmental mitigation practices at nonfederal hydropower projects were analyzed. Information was obtained from project operators on dissolved oxygen (DO) mitigation, instream...
Factors Affecting Dissolved Oxygen in Hydropower Reservoirs
Dissolved oxygen (DO) is becoming a significant issue for hydropower projects. This paper identifies some key factors that can help hydropower operators better understand the nature of...
Side Effect of the Cross-Flow Turbine: Improved Water Quality
The working principle of the Original Cross-Flow Turbine with draft tube demands air induced into the turbine housing to operate at high efficiency. Reoxygenation of water will occur,...
The Gloryhole Approach to Increasing Dissolved Oxygen Content
Deep intakes at hydroelectric dams in southern states withdraw water that is oxygen deficient during summer months when reservoirs become stratified. The 'Gloryhole'...
Deflector Plate Turbine Aeration?Case Studies
Water quality requirements have become a focal point in recent re-licensing of hydroelectric projects. The Federal Energy Regulatory Commission has significantly increased the relevance...
Stream Water Quality Modeling in Ankara Metropolitan Area
At the time this study was undertaken, untreated wastewaters from Ankara metropolitan area (capital of Turkish Republic) were being discharged directly into Ankara Creek and its tributaries....
Tailwater Concerns and the History of Turbine Aeration
All new proposals for hydropower development and many of the almost 300 hydroelectric projects which will be relicensed before 2000 will have to address the issue of minimum dissolved...
Overview of Autoventing Turbine Technology Development Project
Low concentrations of dissolved oxygen (DO) in the discharge of hydro plants represent one of the most significant environmental concerns confronting the hydropower industry. This is especially...
Model Tests for the Evaluation of Auto-Venting Hydroturbines
The most significant environmental problem for many hydroelectric facilities is the water quality of turbine discharges. The primary water quality problem is often low dissolved oxygen...
Return to search