Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Mapping The Volumetric Soil Water Content Of A California Vineyard Using High-Frequency Gpr Ground Wave Data, Susan Sharpless Hubbard, Katherine R. Grote, Yoram N. Rubin
Mapping The Volumetric Soil Water Content Of A California Vineyard Using High-Frequency Gpr Ground Wave Data, Susan Sharpless Hubbard, Katherine R. Grote, Yoram N. Rubin
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
An attempt was made to establish the utility of ground-penetrating radar (GPR) as a quick and noninvasive field tool for shallow soil water content estimates as a function of space and time. Initially, detailed studies of collocated data, with electromagnetic velocity estimates from GPR data compared to gravimetric measurements of water content and to soil testure were carried out. Using the procedures developed during the detailed studies, full grids of GPR data were collected over the entire site several times. Data obtained indicate that incorporation of multiple frequency GPR grids can provide high-resolution estimates of soil water content variations as …
Mechanism For Carrier Velocity Saturation In Pure Organic Crystals, Vasudev M. Kenkre, Paul Ernest Parris
Mechanism For Carrier Velocity Saturation In Pure Organic Crystals, Vasudev M. Kenkre, Paul Ernest Parris
Physics Faculty Research & Creative Works
We present a possible mechanism for the saturation of the velocity of photoinjected charge carriers in pure organic crystals, the analysis having been motivated by observations in pentacene. The mechanism is based on the strong wave vector dependence of the damping coefficient appearing in the appropriate effective mass equation. Our primary goal is to explore this mechanism in general terms rather than to apply it to a specific system such as pentacene. Our analysis is based on a Fokker-Planck equation treatment. We indicate how the damping coeffcient is related to relaxation times in usual Boltzmann equations and how it can …
Gpr Monitoring Of Volumetric Water Content In Soils Applied To Highway Construction And Maintenance, Katherine R. Grote, Susan Sharpless Hubbard, Yoram N. Rubin
Gpr Monitoring Of Volumetric Water Content In Soils Applied To Highway Construction And Maintenance, Katherine R. Grote, Susan Sharpless Hubbard, Yoram N. Rubin
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
An overview is given on two experiments, a controlled pit study and a transportation application in subasphalt soils. Both experiments show that common-offset ground-penetrating radar (GPR) reflection data can be used to estimate θv to a high degree of accuracy. The methodology developed in these two experiments provides a technique for obtaining quick, noninvasive, accurate, and high-resolution estimates of θv.
Saturation Of Charge Carrier Velocity With Increasing Electric Fields: Theoretical Investigations For Pure Organic Crystals, Vasudev M. Kenkre, Paul Ernest Parris
Saturation Of Charge Carrier Velocity With Increasing Electric Fields: Theoretical Investigations For Pure Organic Crystals, Vasudev M. Kenkre, Paul Ernest Parris
Physics Faculty Research & Creative Works
Should one expect injected charge carrier velocities to saturate as the applied electric field is increased simply because of the nonparabolicity of bands? Does the apparent saturation observed in recent experiments in hydrocarbon crystals signify, as supposed in some current interpretations of the data, that the carrier motion is coherent or bandlike and that the disappearance of the saturation at higher temperatures is indicative of a crossover from coherent to incoherent motion? These questions are addressed with the help of general theoretical investigations involving Drude-like considerations, quantum kinetic equations, and a Fokker-Planck analysis.