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Full-Text Articles in Engineering

Model For Trace Metal Exposure In Filter-Feeding Flamingos At Alkaline Rift Valley Lake, Kenya, Yarrow M. Nelson, Ramesh J. Thampy, Gideon K. Motelin, Jackson A. Raini, Cynthia J. Disante, Leonard W. Lion Nov 1998

Model For Trace Metal Exposure In Filter-Feeding Flamingos At Alkaline Rift Valley Lake, Kenya, Yarrow M. Nelson, Ramesh J. Thampy, Gideon K. Motelin, Jackson A. Raini, Cynthia J. Disante, Leonard W. Lion

Civil and Environmental Engineering

Abstract—Toxic trace metals have been implicated as a potential cause of recent flamingo kills at Lake Nakuru, Kenya. Chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) have accumulated in the lake sediments as a result of unregulated discharges and because this alkaline lake has no natural outlet. Lesser flamingos (Phoeniconaias minor) at Lake Nakuru feed predominantly on the cyanobacterium Spirulina platensis, and because of their filter-feeding mechanism, they are susceptible to exposure to particle-bound metals. Trace metal adsorption isotherms to lake sediments and S. platensis were obtained under simulated lake conditions, and a mathematical model was …


Investigation Of A Cyclic Laterally Loaded Model Pile Group, Robb E.S. Moss, Joseph A. Caliendo, Loren R. Anderson Oct 1998

Investigation Of A Cyclic Laterally Loaded Model Pile Group, Robb E.S. Moss, Joseph A. Caliendo, Loren R. Anderson

Civil and Environmental Engineering

In certain regions of the world, designing deep foundations to withstand seismic loading is a reality. Seismic loading of structures and foundations reaches its most critical state as a cyclic lateral force. The response of soils and foundations to repetitive lateral forces is highly complex, relegating most design methods to be based upon overly conservative rules-of-thumb. The primary objective of this research was to analyze the mechanics of seismic loading on pile groups in clay soils. To achieve this a model testing facility was constructed to house a fully instrumented 1 X 5 model pile group that was subjected to …


Seismic Code Improvements Based On Recorded Motions Of Buildings During Earthquake, Anil K. Chopra, Rakesh K. Goel, Juan Carlos De La Llera Sep 1998

Seismic Code Improvements Based On Recorded Motions Of Buildings During Earthquake, Anil K. Chopra, Rakesh K. Goel, Juan Carlos De La Llera

Civil and Environmental Engineering

Summarized in this paper are the results of two recent investigations utilizing recorded motions of buildings to develop improvements in two aspects of seismic code provisions for buildings: (1) fundamental vibration period formulas, and (2) accidental torsion.


Techniques For Modeling Hazardous Air Pollutant Emissions From Landfills, Robert J. Lang, Samuel A. Vigil, Henryk Melcer Jun 1998

Techniques For Modeling Hazardous Air Pollutant Emissions From Landfills, Robert J. Lang, Samuel A. Vigil, Henryk Melcer

Civil and Environmental Engineering

The Environmental Protection Agency’s Landfill Air Estimation Model (LAEEM), combined with either the AP-42 or CAA landfill emission factors, provide a basis to predict air emissions, including hazardous air pollutants (HAPs), from municipal solid waste landfills. This paper presents alternative approaches for estimating HAP emissions from landfills. These approaches include analytical solutions and estimation techniques that account for convection, diffusion, and biodegradation of HAPs. Results from the modeling of a prototypical landfill are used as the basis for discussion with respect to LAEEM results.


Preliminary Development Of A Certification Protocol For Conventional Fireplaces, Paul L. Reitz, Harold M. Cota Jun 1998

Preliminary Development Of A Certification Protocol For Conventional Fireplaces, Paul L. Reitz, Harold M. Cota

Civil and Environmental Engineering

In order to attain and maintain federal and state air quality standards for particulate matter, some local agencies in California have adopted rules and regulations to control emissions from wood burning devices. Some of these rules restricted the use or installation of new masonry fireplaces. The purpose of this study was to begin development of a test protocol that would provide for consistent measurement of particulate emissions from conventional fireplaces and could be useful for compliance determinations or possible certification of a fireplace design or model. A modified California Air Resources Board Stationary Source Test Method 5 was used to …


Experimental Analysis Of Desiccation Crack Propagation In Clay Liners, Carol J. Miller, Hong Mi, Nazli Yesiller Jun 1998

Experimental Analysis Of Desiccation Crack Propagation In Clay Liners, Carol J. Miller, Hong Mi, Nazli Yesiller

Civil and Environmental Engineering

A laboratory investigation on a scaled model of a landfill liner was conducted to provide data regarding the occurrence and extent of desiccation cracking of prototype liners. The crack intensity factor, CIF, was introduced as a descriptor of the extent of surficial cracking. CIF is defined as the ratio of the surface crack area A, to the total surface area of the clay liner, At. A computer aided image analysis program was used to determine CII’ values from scanned photographs of the desiccation process. The variation of the CII’ was related to duration of drying and measured soil moisture suctions. …


Evaluation Of The Us Epa Recommended Approach To Predicting Air Emissions From Pulp And Paper Industry Landfills, Samuel A. Vigil Apr 1998

Evaluation Of The Us Epa Recommended Approach To Predicting Air Emissions From Pulp And Paper Industry Landfills, Samuel A. Vigil

Civil and Environmental Engineering

There is growing indication that the pulp and paper industry will be required to comply with Clean Air Act (Title V) requirements to estimate emissions of bulk bases and HAPs from landfills. One method of such estimation is through the use of the Landfill Air Emissions Estimation Model (LAEEM), which was developed and calibrated specifically for municipal solid waste (MSW) landfills. The industry is concerned with the applicability of LAEEM because the nature of the materials placed in industry landfills is considered to be so different from those in MSW landfills, that emissions will likely be lower than model predictions. …


Energy Efficient Resource Recovery Project, Daniel Panetta, Douglas Williams, Walter Bremer, Gary Karner, Harap Mallareddy, Margot Mcdonald, Samuel A. Vigil, Bailey Green, Henry Hammer, William J. Oswald, William Roley, Jr. Apr 1998

Energy Efficient Resource Recovery Project, Daniel Panetta, Douglas Williams, Walter Bremer, Gary Karner, Harap Mallareddy, Margot Mcdonald, Samuel A. Vigil, Bailey Green, Henry Hammer, William J. Oswald, William Roley, Jr.

Civil and Environmental Engineering

No abstract provided.


Period Formulas For Concrete Shear Wall Buildings, Rakesh K. Goel, Anil K. Chopra Apr 1998

Period Formulas For Concrete Shear Wall Buildings, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

Most seismic codes specify empirical formulas to estimate the fundamental vibration period of buildings. Evaluated first in this paper are the formulas specified in present U.S. codes using the available data on the fundamental period of buildings "measured" from their motions recorded during eight California earthquakes, starting with the 1971 San Fernando earthquake and ending with the 1994 Northridge earthquake. It is shown that current code formulas for estimating the fundamental period of concrete shear wall buildings are grossly inadequate. Subsequently, an improved formula is developed by calibrating a theoretical formula, derived using Dunkerley's method, against the measured period data …


Seismic Code Analysis Of Multi-Storey Asymmetric Buildings, Anthony P. Harasimowicz, Rakesh K. Goel Feb 1998

Seismic Code Analysis Of Multi-Storey Asymmetric Buildings, Anthony P. Harasimowicz, Rakesh K. Goel

Civil and Environmental Engineering

Static torsional provisions in most seismic codes require that the lateral force at each floor level be applied at some distance from the reference centre at that floor. However, codes do not specify how to determine the locations of these centres. As a result, several different definitions of the reference centres are being used to implement the code analysis. This investigation examined how the results using various reference centres differ and which of these centres would lead to results that are in agreement with those of dynamic analysis. For this purpose three different buildings ranging form torsionally stiff to torsionally …


Effects Of Supplemental Viscous Damping On Seismic Response Of Asymmetric-Plan Systems, Rakesh K. Goel Feb 1998

Effects Of Supplemental Viscous Damping On Seismic Response Of Asymmetric-Plan Systems, Rakesh K. Goel

Civil and Environmental Engineering

Coupling between lateral and torsional motions may lead to much larger edge deformations in asymmetric‐plan systems compared to systems with a symmetric plan. Supplemental viscous damping has been found to be effective in reducing deformations in the symmetric‐plan system. This investigation examined how supplemental damping affects the edge deformations in asymmetric‐plan systems. First, the parameters that characterize supplemental viscous damping and its plan‐wise distribution were identified, and then the effects of these parameters on edge deformations were investigated. It was found that supplemental damping reduces edge deformations and that reductions by a factor of up three are feasible with proper …