The mechanism of phosphate adsorption by clay minerals was
reported by Stout. He showed that the loss of water of kaolinite in
the presence of KC1, K₂SO₄ or KH₂PO₄ was due to an exchange reaction
between anion and hydroxyl groups from clay minerals. Also,
Kelly and Midgley reported that the...
The absorption, translocation and metabolism of a new
herbicide, n-propyl-C¹⁴ N, N-di-n-propyl-thiolcarbamate (PDPC), were
studied in both peanut and soybean plants. These studies were
carried out on plants of different ages and treated at two rates of
application. The residue content of the plants was also determined
from germination to...
Studies were undertaken to determine the extent and rate of
binding of Hg-203 labeled phenylmercuric acetate and mercuric ace
tate in rat kidney and liver slices and their subcellular fractions
after 37°C incubation of the slices in Krebs-Ringer -phosphate solutions
containing the mercurials at 10⁻⁴ molar. A fast and parallel...
Normal adult rats absorbed and metabolized C¹⁴-labeled acetate
rapidly. The greatest percentage of the administered radioactivity
was recovered in the expired CO₂, however small amounts of radioactivity
were also found in the urine and feces. There were two rates
of C¹⁴O₂ elimination in normal adult rats. The small amount of...
A single oral dose of DDT, ranging from 40 to 200 mg/kg, had
a drastic effect on the in vivo acetate metabolism in rats. The normal
elimination pattern of the expired ¹⁴CO₂ from ¹⁴C-labelled
acetate was distorted, and the rate of output of the ¹⁴CO₂ was decreased.
The ratio of...
The metabolism of ¹⁴C-labeled ethyl -N, N-di-n- propylthiolcarbamate
(EPTC- ¹⁴C) was studied in adult female rats. Single
oral doses of EPTC-¹⁴C ranging from 0. 6 to 100. 6 mg were given
and the elimination pattern of ¹⁴C was determined.
Results of 18 experiments showed that increasing the doses
of EPTC-...
Biochemical studies of phenylmercuric acetate (PMA) and
mercuric acetate toxicity in rats carried out during this investigation
were (1) the metabolism of ²⁰³Hg(Ac)₂ and ²⁰³Hg-PMA within kidney and liver tissues following oral
ingestion,
(2) the effect on some
soluble enzyme activities and determinations of ²⁰³Hg binding in the
enzyme fractions,...
An optimization methodology, algorithms, and computer program for
cable/lumped-body deployment system are developed for the design and installation of
sonar packages in deep ocean ranges. In addition, a methodology and algorithms for the
control of the system are proposed.
A penalty function is developed in terms of the system parameters...
In this paper we investigate the Lyapunov mapping
P --> AP + PA *
where A is a positive stable matrix and P is a hermitian
matrix. In particular, for special positive stable A we
characterize the image of the cone of positive definite matrices
under this mapping. In Section...
This investigation deals with the chaotic rocking response and overturning
stability of offshore equipment subjected to base excitations due to wave-induced
motions of the supporting compliant offshore structural system. The equipment
compliant structural system is modelled as a free-standing rigid object subjected
to horizontal and vertical base accelerations. Three of...
Complex nonlinear and chaotic responses have been recently observed in various
compliant ocean systems. These systems are characterized by a nonlinear mooring
restoring force and a coupled fluid-structure interaction exciting force. A general class
of ocean mooring system models is formulated by incorporating a variable mooring
configuration and the exact...
Stochastic analysis procedures have been recently applied to analyze nonlinear
dynamical systems. In this study, nonlinear responses, stochastic and/or chaotic, are
examined and interpreted from a probabilistic perspective. A multi-point-moored
ocean structural system under regular and irregular wave excitations is analytically
examined via a generalized stochastic Melnikov function and Markov...
Recent developments in estimation of the survivability of a U.S. Navy transport barge in random seas are extended to improve accuracy. The single Degree-of-Freedom (DOF) model of a extreme roll response of a barge used in previous research is replaced by a 3-DOF roll-heave-sway model to include linear and nonlinear...
The (nonlinear) response behavior of a piecewise-linear system is investigated under
both deterministic and stochastic excitations in this study. A semi-analytical procedure is
developed to predict the system behavior by evaluating the joint probability density functions
of the Fokker-Planck equations of the stochastic piecewise-linear system under random
excitations via a...
Base isolation is an alternative seismic design strategy in which the primary structures
and their internal components are uncoupled from the potentially damaging horizontal
components of an earthquake by base isolators which attenuate the transmission of
horizontal acceleration into the system. Rotating machines are among the key internal
components of...
Response behavior of a nonlinear structural system subject to environmental loadings
is investigated in this study. The system contains a nonlinear restoring force due to large
geometric displacement. The external excitation is modeled as a narrowband stochastic
process possessing dynamic characteristics of typical environmental loadings.
A semi-analytical method is developed...
The nonlinear response of an ocean system subjected to random excitations can exhibit very complex dynamic behaviors including jump phenomena and coexistence of attractors. In this study, the stochastic system response behavior of a simple (Duffing) oscillator under narrow-band random excitations is first examined in the subharmonic resonance region. A...
The present research investigates nonlinear barge motions through analyses of coupled multi-degree-of-freedom (MDOF) deterministic and stochastic models. Roll-Heave-Sway and other lower-ordered models are developed to predict the nonlinear motions and analyze the stability of a class of ship-to-shore cargo barges. The governing equations of motion contain coupled rigid body Roll-Heave-Sway...
Complex oscillations including chaotic motions have been identified in off-shore and submerged mooring systems characterized by nonlinear fluid-structure interactions and restoring forces. In this paper, a means of controlling these nonlinear oscillations is addressed. When applied, the controller is able to drive the system to periodic oscillations of arbitrary periodicity....
The reliability of ocean systems is dependent on organizational factors. It has been shown that low probability / high consequence system failures are overwhelmingly induced by organizational factors. However, no methodology is yet widely accepted for the evaluation of this phenomenon or its accurate quantification. A qualitative complementary approach is...
This paper studies necessary and sufficient conditions for
a matrix to be conjunctive with its adjoint. The problem is solved
completely in the usual complex case, in which it is shown that a
matrix is conjunctive to its adjoint iff it is conjunctive to a real
matrix. The problem is...
In this thesis we define two nxn matrices T and S to be isoconjunctive if there exists an nxn nonsingular hermitian matrix H such that T = HSH. We then proceed to establish necessary and sufficient conditions that two nxn matrices T and S be isoconjunctive in the case where...
Nutrient limitation constrains tree growth in many managed forests. Nitrogen (N) is the most common limiting nutrient, but high N supply can shift limitation to other nutrients, particularly phosphorus (P) and the base cations calcium (Ca), magnesium (Mg), and potassium (K). As different soil minerals have different capacities to supply...
Time-domain models were developed to predict the response of a tethered buoy
subject to hydrodynamic loadings. A coupled analysis of the interaction of a buoy and
its mooring is included and three-dimensional response is assumed. External loadings
include hydrodynamic forces, tethers tensions, wind loadings and the weight of both
cable...
The deglacial behavior of the sub-Arctic North Pacific is poorly constrained, with many published records suffering from limited age control due to extensive post- depositional biogenic carbonate dissolution. Potential alternative dating methods could include the correlation of stable-isotopic and/or paleomagnetic secular variation records to an independently-dated regional template, however no...
Livestock grazing has been indirectly related to sage-grouse (centrocercus
urophasianus) declines in the western United States and southern Canada; however,
there is a lack of scientific research that directly relates the two. Our objective was
to investigate the influence of livestock herbivory on sage-grouse nesting habitat by
determining the spatial...
The Horsetail Creek (HC) bridge is an example of an Oregon bridge that was classified as structurally deficient and was not designed to withstand earthquake (EQ) excitations. A fiber-reinforced polymer (FRP) rehabilitation was performed on the HC bridge to increase flexural and shear capacities for traffic loads. However, a seismic...
Improving quality of hard white wheat (HW) cultivars in the Pacific Northwest is important to expand exports to Asia. Asian food processors prefer HW grain that can satisfy an array of baking needs, as well as produce superior quality noodle products. Three experimental populations were developed from single cross and...
A numerical model for the simulation of fully-coupled fluid-structure
interaction is developed in this study. In modeling the fluid, the Reynolds
Averaged Navier-Stokes equations are solved for an incompressible viscous
fluid field and a k-ε model is employed for turbulence computations.
Hydrodynamic forces obtained by the integration of the fluid...