Thin foil samples of special nuclear materials (SNMs) were irradiated for 60s using a Mark TRIGA II reactor, and their associated gamma emissions were recorded with a count time of 60s following irradiation. A rapid pneumatic transfer system was used to irradiate the samples in front of beam port #4....
Natural uranium samples were irradiated in-core for 7 seconds using the pneumatic rabbit system within the TRIGA Mark II Reactor at Oregon State University, and then used to generate a gamma-ray spectrum with a high purity germanium (HPGe) detector. The irradiated sample was simulated in Monte Carlo N-Particle (MCNP), a...
Two experiments were conducted on the invasive plant species Potentilla recta in northeastern Oregon to investigate both biological and ecological characteristics of the species. Growth analysis was conducted on the plant at three sites over a period of two years (2002 and 2003). Relative growth rate (RGR) was calculated for...
Plant form is a compromise between resource gathering, reproduction and
the tolerance to physical demands of the abiotic and biotic environment. In
an agricultural field in addition to the natural factors causing stress, humans
also introduce physical and mechanical stresses, and chemical pesticides
into the environment. Many of these factors...
This thesis consists of four chapters. Literature is
reviewed in Chapter 1. Chapter 2 describes an addition
series experiment to determine the influence of species
density and proportion on vegetative and reproductive yield
of spring wheat and Lolium multiflorum. Chapter 3 consists
of a growth analysis experiment to determine whether...
Oregon land use specialists believe that the present
definitions of farm and forest land in the state planning
goals are too broad. This results in poor quality resource
lands being as strongly protected as those of top quality.
With persistent growth pressure on rural lands, a means to
distinguish among...
Models of weed communities aid in the development of
weed management strategies and elucidate the processes
and mechanisms that regulate plant populations and
communities. A conceptual weed community model was
developed to organize key regulatory life-history
processes. Specific investigations focused on the
processes of plant growth and competition, and
relationships...
Neutron radiography has been used to study cementitious materials. This thesis studies the impact of heavy water on both the rate of hydration and neutron radiography. The neutron attenuation coefficients of light and heavy water were measured. Cement pastes were made with both heavy and light water. The attenuation coefficients...
A new method for delayed gamma-ray spectrometry to quantify the relative content of fissile material is developed and demonstrated to support international efforts in bolstering non-destructive assay capabilities. Previous traditional delayed gamma-ray spectrometry techniques rely upon nuclear data that often carry very high uncertainty. The new method removes the requirement...