Characterizing special nuclear material (SNM) is critical for nuclear security and non-proliferation. Temporal spectroscopy is a novel and efficient method for characterizing relative material content of special nuclear material. Fission products produced by SNM after being irradiated by a thermal neutron beam can have different half-lives, but can contribute to...
Quick and accurate measurements of nanoparticles have important applications in biology, environmental and non-proliferation areas. Calculation of isotopic ratios, particularly in special nuclear materials, has relied on integration of nanoparticle counts and limited the capability of counting minor isotopes. Rapid transient detection method of nanoparticles has demonstrated the effectiveness of...
Sensor design and mission planning for satellite ocean color measurements requires careful consideration of the signal dynamic range and sensitivity (specifically here signal-to-noise ratio or SNR) so that small changes of ocean properties (e.g., surface chlorophyll-a concentrations or Chl) can be quantified while most measurements are not saturated. Past and...
Space-based observations offer unique capabilities for studying spatial and temporal dynamics of the upper ocean inorganic carbon cycle and, in turn, supporting research tied to ocean acidification (OA). Satellite sensors measuring sea surface temperature, color, salinity, wind, waves, currents, and sea level enable a fuller understanding of a range of...
The Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission was recommended by the National Research Council's (NRC's) Earth Science Decadal Survey to measure tropospheric trace gases and aerosols and coastal ocean phytoplankton, water quality, and biogeochemistry from geostationary orbit, providing continuous observations within the field of view. To fulfill the...
The atmospheric detection of four radioxenon isotopes (131mXe, 133mXe, 133Xe, and 135Xe) released during a nuclear detonation is a key tool utilized by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) to identify clandestine nuclear weapon testing activity. These radioxenon isotopes all decay via the near-simultaneous release of an electron and a...
Recent statistics suggest that the construction industry continues to experience poor project performance. Specifically, construction productivity has witnessed a meager annual growth of 1% over the past 20 years while the industry constantly records both a high number of fatalities and a high fatality rates relative to other industries. The...
For hundreds of years, coastal and marine ecosystems have experienced increasing threats due to the cumulative effects of increasing population growth and dependence on these ecosystems. Thus, there has been increased enthusiasm to mitigate the negative effects of human actions through the use of cleaner sources of energy, like marine...
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...
Oyster shell is a crucial component of healthy oyster reefs. Shell planting has been a main component of oyster restoration efforts in many habitats and has been carried out on scales from individual and grassroots efforts to multiagency efforts across entire estuaries. However, the cycling and lifetime of the shell...