Throughout the western United States, the invasive annual grass, medusahead (Taeniatherum caput-medusae L. Nevski), is rapidly invading grasslands once dominated by native perennial grasses, such as bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A). It is also invading grasslands dominated by less undesirable invasive annual grasses, especially cheatgrass (Bromus tectorum L.). Understanding...
Interstitially filled skutterudites are a promising class of state-of-the-art thermoelectric
materials. Although thermoelectrics are exposed to significant thermal stresses, little
information is known about the fracture toughness of interstitially doped skutterudites. This
work explores the fracture toughness of undoped Co₄Sb₁₂ and indium doped In₀.₁Co₄Sb₁₂
skutterudites using three methods: 1) Vickers...
An experimental investigation of a two·dimensional turbulent jet in a quiescent environment has been
carried out to determine the structural characteristics of the outer, intermittent turbulent motion. An
overall picture of this motion was deduced from the results which indicate that, on the average, the
turbulent bulges are of the...
Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer which viewed a disc on the surface 12 cm in diameter. The instrument responded to frequencies...
Optical oceanography models of attenuation and scattering properties often contain simple spectral relationships. Electromagnetic theory, however, predicts fluctuations in the spectra of the attenuation coefficients and scattering properties of substances at wavelengths near an absorption peak. We have modeled these effects for phytoplankton using homogeneous, two‐layered, and three‐layered sphere models...
The relationships between beam attenuation, absorption, suspended particle concentration, size distribution and pigment content are examined for a region where the particle concentration and pigment maxima are widely separated. Mie scattering analyses are performed on this data to predict the profiles of backscattering. It was found that absorption and scattering...
The uptake of methylammonium (MA) by Chesapeake Bay phytoplankton was measured in short term experiments by using the 14C radioisotope. This uptake was inversely related to ambient NH4+ concentrations, and the specificity for uptake of both substrates was demonstrated by competitive inhibition. At stations with low ambient NH4+, MA uptake...
Observations were made of downward solar radiation as a function of depth during an experiment in the North Pacific (35°N, 155°W). The irradiance meter employed was sensitive to solar radiation of wavelength 400–1000 nm arriving from above at a horizontal surface. Because of selective absorption of the short and long...
Theoretical scattering computations are performed on a phytoplankton model consisting of three
concentric spheres. The outer sphere represents the wall, membrane, or frustule and is assigned a
relatively high index of refraction with no absorption. The middle layer represents the chloroplasts
and is assigned a relatively low index of refraction...
A method for predicting oceanic productivity from remotely sensed diffuse attenuation (488 nm) and
surface chlorophyll concentration is presented. The method uses a climatological approach which consists
of applying a set of regressions for each region and season to yield the depth of the chlorophyll maximum,
the exponential slope of...