Physical Sciences and Mathematics Commons^™

Morphogenesis Of Douglas Fir Buds Is Altered At Elevated Temperature But Not At Elevated Co2, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

Global climatic change as expressed by increased CO₂ and temperature has the potential for dramatic effects on trees. To determine what its effects may be on Pacific Northwest forests, Douglas-fir (Pseudotsuga menziesii ) seedlings were grown in sun-lit controlled environment chambers at ambient or elevated (+4°C above ambient) temperature, and at ambient or elevated (+200 ppm above ambient) CO₂. In 1995–1996 and 1996–1997, elevated CO₂ had no effect on vegetative bud morphology, while the following unusual morphological characteristics were found with greater frequency at elevated temperature than at ambient: rosetted buds with reflexed and loosened outer …

Application Of Mathematical Modeling And Computer Simulation For Solving Water Quality Problems, Jacek Makinia, Scott A. Wells, David Crawford, Marian Kulbik

Civil and Environmental Engineering Faculty Publications and Presentations

Deteriorated water resources in Central and Eastern Europe call for actions that should be undertaken to improve current conditions and to protect human and environmental health. Mathematical modeling and computer simulation is often an integral part of the decision-making process. Models and simulations allow rapid and varied evaluation of causes and effects and the principal advantage is that they enable an analysis of even long-term actions with limited investment costs. This paper provides an overview of popular models used for simulation of major elements of a water quality system: surface water quality (QUAL2E), wastewater treatment (Activated Sludge Model No.1), sewer …

Water Flow Through Temperate Glaciers, Andrew G. Fountain, Joseph S. Walder

Geography Faculty Publications and Presentations

Understanding water movement through a glacier is fundamental to several critical issues in glaciology, including glacier dynamics, glacier-induced floods, and the prediction of runoff from glacierized drainage basins. To this end we have synthesized a conceptual model of water movement through a temperate glacier from the surface to the outlet stream. Processes that regulate the rate and distribution of water input at the glacier surface and that regulate water movement from the surface to the bed play important but commonly neglected roles in glacier hydrology. Where a glacier is covered by a layer of porous, permeable firn (the accumulation zone), …

The Selfish Book. Review Of: The Origins Of Virtue: Human Instincts And The Evolution Of Cooperation By Matt Ridley, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

Book Review of The Selfish Book. Review of: The Origins of Virtue: Human Instincts and the Evolution of Cooperation by Matt Ridley

Ecological Tax Reform, Robert Costanza, Steve Bernow, Herman E. Daly, Robert Degennaro, Paul Hawken

Institute for Sustainable Solutions Publications and Presentations

Provides an overview detailing the benefits of ecological tax reform. What ecological tax reform would include; Origin of ecological taxes; Implementation in the United States and Europe; Specifics on an ecological tax reform proposal; The need to phase in tax reforms gradually.

Modeling Density Currents In Circular Clarifiers, Scott A. Wells, David M. Laliberte

Civil and Environmental Engineering Faculty Publications and Presentations

Design of sedimentation tanks for solid-liquid separation is often dependent on assuming ideal flow conditions. But the geometry of the tank and density currents as a result of temperature and suspended solids influences the fluid mechanics of the tank and can result in significant deviations from ideal flow.

A two-dimensional radial flow model was proposed which incorporated the effect of density currents resulting from temperature and suspended solids differentials within the tank. The numerical model predicted the steady-state, layer-averaged radial flow and layer depth.

The model solution and field data showed that the momentum and suspended solids of the inflow …

Will Business-Led Environmental Initiatives Grow In Agriculture?, Sandra S. Batie, David E. Ervin

Economics Faculty Publications and Presentations

This article was stimulated by a 1997 American Agricultural Economics Association annual meeting preconference designed by Batie and Ervin. The authors felt that there was considerable interest and activity in business-led environmental management (also caLLed corporate environmental management)-but most of the interest was found outside of the agricultural sector and the profession. The conference was a means to investigate the extent, motivation, and consequences of business-led poLLution prevention activities. The DuPont and the StahLbush Island Farms examples used in this article were drawn from discussions that took place at the conference and which were published in the proceedings. In the …

Soil Moisture Gradients And Controls On A Southern Appalachian Hillslope From Drought Through Recharge, J. Alan Yeakley, W. T. Swank, L. W. Swift, G. M. Hornberger, H. H. Shugart

Environmental Science and Management Faculty Publications and Presentations

Soil moisture gradients along hillslopes in humid watersheds, although indicated by vegetation gradients and by studies using models, have been difficult to confirm empirically. While soil properties and topographic features are the two general physio-graphic factors controlling soil moisture on hillslopes, studies have shown conflicting results regarding which factor is more important. The relative importance of topographic and soil property controls was examined in an upland forested watershed at the Coweeta Hydrologic Laboratory in the southern Appalachian mountains. Soil moisture was measured along a hillslope transect with a mesic-to-xeric forest vegetation gradient over a period spanning precipitation extremes. The hillslope …

Filtration Modeling Of A Plate-And-Frame Press, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The porosity distribution and filtrate production during cake filtration in a plate-and-frame filter press were simulated mathematically. The model considered filtration that occurs after the filling process, not filtration that occurs as the suspension fills the cell. Governing equations for the temporal porosity distribution were developed for a plateand- frame press. The governing equations were solved numerically using an alternating-direction-implicit scheme. Appropriate initial and boundary conditions were determined based on characteristics of the plate-and-frame press and of the suspension properties. Predicted porosity and velocity distributions were calculated for assumed constitutive parameters.

Gravity Drainage Prior To Cake Filtration, Scott A. Wells, Gregory K. Savage

Civil and Environmental Engineering Faculty Publications and Presentations

During the initial stages of a Buchner funnel or specific resistance test, gravity drainage occurs prior to application of the pressure differential. Some allow time for a small cake to form by gravity drainage. Filtrate data from the gravity drainage period can be used to determine constitutive properties of the cake under a hydrostatic pressure gradient. The constitutive properties that define the structure of the cake include the permeability and porosity as functions of the applied stress. Equations governing the drainage rate during a gravity filtration experiment assuming a constant and a non-constant average cake permeability and cake porosity were …