Search Results - "Wittman, Richard S."

Novamene: A new class of carbon allotropes by Burchfield, Larry A, Fahim, Mohamed Al, Wittman, Richard S, Delodovici, Francesco, Manini, Nicola

“…We announce a new class of carbon allotropes. The basis of this new classification resides on the concept of combining hexagonal diamond (sp3 bonded carbon −…”
Get full text

Does a cosmological constant with a measurement constraint enable the existence of spacetime? by Wittman, Richard S., Tank, Leon C.

“…We ask a basic question about how or if the existence of observable spacetime (not only its geometry) is predicted in solutions to the Einstein equations of…”
Get full text

Protomene: A new carbon allotrope by Delodovici, Francesco, Manini, Nicola, Wittman, Richard S., Choi, Daniel S., Al Fahim, Mohamed, Burchfield, Larry A.

“…We introduce a new carbon allotrope named protomene. Its crystal structure is hexagonal, with a fully-relaxed primitive cell involving 48 atoms. Of these, 12…”
Get full text

Monitoring bromide effect on radiolytic yields using in situ observations of uranyl oxide precipitation in the electron microscope by Buck, Edgar C, Wittman, Richard S, Soderquist, Chuck Z, McNamara, Bruce K

“…During electron microscopy observations of uranium-bearing phases and solutions in a liquid cell, the electron beam induced radiolysis causes changes in the…”
Get full text

Isolation of Au and Pt radionuclides from deuteron-irradiated platinum using TBP resin by Morrison, Samuel S., Morrison, Erin C., Uhnak, Nicolas E., Wittman, Richard S., Seiner, Brienne N.

“…A separation procedure was developed and implemented for the isolation of gold (Au) and platinum (Pt) radionuclides from deuteron irradiated Pt using tri-butyl…”
Get full text

Conditions for Critical Effects in the Mass Action Kinetics Equations for Water Radiolysis by Wittman, Richard S, Buck, Edgar C, Mausolf, Edward J, McNamara, Bruce K, Smith, Frances N, Soderquist, Chuck Z

“…We report on a subtle global feature of the mass action kinetics equations for water radiolysis that results in predictions of a critical behavior in H2O2 and…”
Get full text

Multiple-estimate Monte Carlo calculation of the dose rate constant for a cesium-131 interstitial brachytherapy seed by Wittman, Richard S., Fisher, Darrell R.

“…The purpose of this study was to calculate a more accurate dose rate constant for the Cs 131 (model CS-1, IsoRay Medical, Inc., Richland, WA) interstitial…”
Get full text

Radiography Scatter Estimation for Accurate Material Quantification by Gilbert, Andrew J., Campbell, Luke A., Deshmukh, Nikhil, Wittman, Richard S.

“…Scatter is a common source of noise in radiography systems, and is particularly problematic for any quantitative analysis. Not only can scatter reduce the…”
Get full text

Configuration and impurity quantification of AmLi sources using radiography and gamma spectroscopy by Moore, Michael E., Mozhayev, Andrey V., Wittman, Richard S., Mace, Emily K.

“…This paper presents the non-destructive assay of two AmLi sources used for detector characterization and active interrogation at PNNL, identified as MRC-101…”
Get full text

A 3D simulation look-up library for real-time airborne gamma-ray spectroscopy by Kulisek, Jonathan A., Wittman, Richard S., Miller, Erin A., Kernan, Warnick J., McCall, Jonathon D., McConn, Ron J., Schweppe, John E., Seifert, Carolyn E., Stave, Sean C., Stewart, Trevor N.

“…A three-dimensional look-up library consisting of simulated gamma-ray spectra was developed to leverage, in real-time, the abundance of data provided by a…”
Get full text

Monitoring bromide effect on radiolytic yields using in situ observations of uranyl oxide precipitation in the electron microscopeElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ra01706a by Buck, Edgar C, Wittman, Richard S, Soderquist, Chuck. Z, McNamara, Bruce K

“…During electron microscopy observations of uranium-bearing phases and solutions in a liquid cell, the electron beam induced radiolysis causes changes in the…”
Get full text

Improved Cumulative Fission Yield Measurements with Fission Spectrum Neutrons on 238U by Pierson, B.D., Greenwood, L.R., Stave, S.C., Harke, J.T., Padgett, S.W., Prinke, A.M., Goda, J.M., Bounds, J.A., Hayes, D.K., Tamashiro, A.S., Wittman, R.S., Slavik, G., Dion, M.P., Burch, J.G., Palmer, T.S.

“…Two isotopically-characterized targets of high-purity (99.961±0.002%) 238U metal and a neutron dosimetry package were exposed to a pulsed neutron irradiation…”
Get full text

Design and testing of a 10B4C capsule for spectral-tailoring in mixed-spectrum reactors by Greenwood, L.R., Wittman, R., Metz, L.A., Finn, E.C., Friese, J.I.

“…A boron carbide capsule highly enriched in 10B has been designed and used for spectral-tailoring experiments at the TRIGA reactor at Washington State…”
Get full text

Cumulative fission yields of short-lived isotopes under natural-abundance-boron-carbide-moderated neutron spectrum by Finn, Erin C., Metz, Lori, Greenwood, Larry, Pierson, Bruce, Wittman, Richard, Friese, Judah, Kephart, Rosara

“…This work expands the availability of energy-resolved short-lived cumulative fission product yields for 235,238,233 U, 239 Pu, and 237 Np subjected to a 2$…”
Get full text

Modeling and production of 240Am by deuteron-induced activation of a 240Pu target by Finn, Erin C., McNamara, Bruce, Greenwood, Larry, Wittman, Richard, Soderquist, Charles, Woods, Vincent, VanDevender, Brent, Metz, Lori, Friese, Judah

“…A novel reaction pathway for production of 240Am is reported. Models of reaction cross-sections in EMPIRE II suggest that deuteron-induced activation of a…”
Get full text

Multiple-estimate Monte Carlo calculation of the dose rate constantfor a cesium-131 interstitial brachytherapy seed by Wittman, Richard S., Fisher, Darrell R.

“…The purpose of this study was to calculate a more accurate dose rate constant for the Cs 131 (model CS-1, IsoRay Medical, Inc., Richland, WA) interstitial…”
Get full text

Verifying the presence of low levels of neptunium in a uranium matrix with electron energy-loss spectroscopy by Buck, Edgar C., Douglas, Matt, Wittman, Rick S.

“…This paper examines the problems associated with analysis of low levels of neptunium in a uranium matrix with electron energy-loss spectroscopy (EELS) on the…”
Get full text

Candidate reactions for mercury detection induced by neutron and alpha particles by Toth, James J., Wittman, Richard, Schenter, Robert E., Cooper, John A.

“…This paper summarizes modeling of mercury to activated states with alpha particles, neutrons, or deuterons, and the spectral emission from the activated…”
Get full text

Combining radiography and passive measurements for radiological threat detection in cargo by Miller, Erin A., White, Timothy A., Jarman, Kenneth D., Kouzes, Richard T., Kulisek, Jonathan A., Robinson, Sean M., Scherrer, Chad, Wittman, Richard A.

“…Radiography is widely understood to provide information complementary to passive gamma-ray detection systems: while not directly sensitive to radiological…”
Get full text

Design and Testing of a Boron Carbide Capsule for Spectral Tailoring in Mixed-Spectrum Reactors by Greenwood, L. R., Wittman, R., Pierson, B. P., Metz, L. A., Payne, R., Finn, E. C., Friese, J. I.

“…A boron carbide capsule has been designed and used for spectral-tailoring experiments at the TRIGA reactor at Washington State University. Irradiations were…”
Get full text