Origin of Carbonate Deposits in the Vicinity of Yucca Mountain, Nevada: Preliminary Results of Strontium-Isotope Analyses
As part of the paleohydrology study of the Yucca Mountain Project, strontium-isotope analyses of carbonate deposits, ground water, and major rock reservoirs of strontium are in progress....
Uranium-Series Dating of Secondary Carbonates Near Yucca Mountain, Nevada: Applications to Tectonic, Paleoclimatic, and Paleohydrologic Problems
Near-surface accumulations of secondary carbonates are common in the soils and sediments of the Yucca Mountain area. These carbonates contain small amounts of uranium that allow dating...
Removal of Scale from Potable Hot Water Systems by Carbon Dioxide Injections
An innovative method for inplace scale removal has been developed and demonstrated. Injection of carbon dioxide gas into a piping system can lower the pH of the hot water and remove or...
Carbon Dioxide Release from OTEC Cycles
This paper presents the results of recent measurements of CO2 release from an open-cycle ocean thermal energy conversion (OC-OTEC) experiment. Based...
On the Road to Clean Air
Anticipating passage of the 1990 Clean Air Act in the fall of the year, this article examines the remaining air quality problems in U.S. cities and some efforts underway or being planned...
Experiments on Active Structural Control Under Seismic Loads
Two control systems, an active tendon system and an active mass damper system are selected for study for possible real structural implementation. Presented in this paper are simulation...
Tradeoffs Between Active Control and Identification of Structural Systems
This paper explores the tradeoffs between structural identification and structural control in a quantitative manner. Through the intemediary concept of an optimal input, it is shown that...
Contact Stabilization Process Analysis and Formulation
In this paper, the contact stabilization process is analyzed. In comparison to the conventional activated sludge process, there are a larger number of independent design variables involved...
Importance of Aeration Basin Detention Time in the Activated Sludge Process
Aeration basin detention time is a key design parameter for an activated sludge system at a wastewater treatment plant. The impacts of reducing the aeration time is illustrated by a case...
Control of
The paper reports on a study to determine the cause(s) of the biological imbalance and identify corrective measures. Project activities included: isolation and identification of filamentous...
Optimizing the Activated Sludge Process by Encouraging Futile Cycling
A study was conducted to demonstrate that cell yield in activated sludge processes can be decreased without increasing oxygen consumption by applying operating conditions that encourage...
Gamma Exposure from Rn Progeny in GAC Units
An investigation into the gamma exposure rate generated by granular activated carbon (GAC) water treatment units focused on ten sites that covered a range of source radon (Rn) in water...
Treatment Plant Modifications to Conserve Energy and Improve Performance
Creative funding along with thorough planning and design contributed to the successful energy conservation program at the Willow Lake Wastewater Treatment Plant, Salem, Oregon. By funding...
Comparison of Centrifuge Performance on Oxygen Activated Sludge
This paper compares the performance of centrifuges processing high purity oxygen activated sludge with units processing conventional activated sludge. Comparisons are made both for thickening...
Fate and Effect of Carbon Tetrochloride and O-Xylene on Anaerobic Systems with Sulfate Reducing Bacteria
The fate and effects of o-xylene and carbon tetrachloride on methanogens and sulfate reducing bacteria were investigated using serum bottles. Up to 750 mg/1 of o-xylene did not cause any...
Fly Ash Utilized in Concrete?Technology Update
Fly ash is frequently utilized as a pozzolanic substance in Portland cement concrete. Levels of such utilization, a reflection of current practice/technology, seem to have stabilized at...
Social Science, Engineering and Water Resources Management: A Perspective
This paper shares a framework or context for professional activities of social scientists in water resources management. It emphasizes the positive opportunities for helping and not simply...
Active Control of Distributed Parameters Structures by Pointwise Control Actions
Several methods have been offered to control a structure. These methods are the optimal control, the pole assignment, the independent modal space control, and the direct velocity feedback....
An Experimental Study of Active Structural Control
An experimental investigation is made concerning the possible application of active control to structures under seismic excitation. The experimental facilities and structural model are...
The Optimization of Nitrification and Denitrification in Plug-Flow Activated Sludge Systems Treating Municipal Wastestreams
Most conventional plug-flow activated sludge plants experience nitrification, particularly during higher temperature conditions. Under these circumstances, additional power is required...
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