Trace metals in the aquatic environment are generally concentrated
on the surface of solid geochemical phases which eventually become incorporated
into estuarine and marine sediments. The mechanism of trace
metal concentration is believed to be adsorption with various geochemical
phases such as hydrous metal oxides, clays, and organic matter.
Metals...
Post-tensioned (PT) self-centering shear walls were designed to reduce structural damage from seismic activity. However, these lateral force resistant systems experience post-tension loss negatively affecting the re-centering capability due to delayed deformations experienced by engineered wood products over time. The long-term mechanical response of mass-timber panels to in-plane PT loads...
The objective of this study was to provide first order observations of bed level changes occurring in streambed simulated culverts throughout an annual period. To accomplish this, 30 culvert sites were selected in Oregon and Washington, and monitored over, at least, a 2 year period. Streambed scour and redeposition data...
An evaluation of the service time of an activated carbon adsorption
column and the organic carbon removal efficiency treating activated
sludge process effluent was completed at aerator detention
times of three, five, and ten hours. Parameters used for evaluation
of treatment were biochemical oxygen demand, chemical oxygen
demand, total organic...
A conceptual model was developed to further the understanding
of the evolution and fate of volatilized ammonia in
the atmosphere. Recent trends in livestock rearing have
been toward confinement facilities in which high animal concentrations
are maintained. One of the impacts of these
facilities has been increased local concentrations of...
A laboratory study of anaerobically digested sewage
sludge was performed to measure equilibrium constants for
ammonia in the sludge. Measured constants describing the
solution and dissociation of ammonia in sludge were compared
to theoretical constants obtained from thermodynamic data.
No significant difference was found between these two sets
of constants....
Heavy timber framing relies primarily on bracing to withstand lateral loads due to earthquakes and wind events. Bracing configurations in heavy timber framed buildings vary widely and include cross bracing, knee bracing, and other geometries. Many heavy timber frames constructed during colonial American times are still standing, exceeding the expected...
This paper investigates a particular bridge construction technique
which could result in a significant torsional moment. The
structural member under consideration is a prestressed concrete
girder for which no torsional consideration is made.
Torsional shear stresses can be adequately approximated for
an I-shaped girder. Laboratory model tests were performed to...
The biochemical degradation of domestic sludge deposits exposed to benthic marine conditions was investigated using a laboratory Deep Sea Simulator. The rate and extent of deposit stabilization were determined for select hydrostatic pressures and hydrogen acceptor conditions by monitoring depletion of particulate organic carbon in 2.0 and 3.0 centimeter deposits....