Myocardial Wall Stress: A Clinician's View
Definition of left ventricular (LV) wall stress is a parameter which has a valid application in clinical medicine. This paper discusses this application as it pertains to various cardiac...
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...
Anoxic-Aerobic Activated Sludge Treatment
An activated sludge system was operated at a relatively low SRT of 1-2 days at the City of Phoenix to meet secondary treatment requirements. Operating MLSS concentrations were 400-600...
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...
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...
Experimental Difficulties Encountered in Testing Air/Water Mixtures
The Tennessee Valley Authority and Voith Hydro, Inc., are conducting a joint research project to study the effects of air admission on hydraulic turbines. Francis turbine models, homologous...
Energy Losses Due to Air Admission in Hydroturbines
Admission of air at the exit of a hydroturbine runner is an attractive technique for raising dissolved oxygen levels downstream of a hydro plant. The air admission, however, is generally...
Numerical Modeling of Air/Water Mixtures for Internal Flows
The Tennessee Valley Authority (TVA) currently is working with several organizations to develop design tools for the aerating hydroturbine. Part of this effort includes the investigation...
Efficiency and Cavitation Effects of Hydroturbine Venting
Volkart and Bohac et al. have summarized much of the past work on aeration of hydroturbine releases to improve downstream water quality. Conventional alternatives for increasing dissolved...
Reviewing the Operating Objectives of the TVA Reservoir System
Under the Tennessee Valley Authority's Lake Improvement Plan, approved by the Board of Directors in February 1991, minimum flows will be provided systemwide, the releases...
Effect of Temperature on Gas Transfer at Low Surface Renewal Rates
In order to investigate the dependence of gas transfer coefficients on temperature under conditions of low surface renewal rates, laboratory experiments were conducted using simultaneous...
Turbulent Water Aeration: Analytical Approach and Experimental Data
Analytical studies based on the statistical theory of turbulence were carried out in order to identify some relevant parameters which may be associated with the reaeration rate coefficient...
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