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Monitoring Neutron Generator Output in a Mixed Neutron-Gamma Field Using a Plastic Scintillator.

Description: Quantitative neutron-induced gamma-ray spectroscopy employing neutron generators (NGs) entails monitoring them for possible fluctuations in their neutron output. We accomplished this using a plastic scintillator and recording a spectrum from which we selected a neutron region-of-interest (nROI) to discriminate between neutrons and the accompanying high-energy gamma-rays. We show that the selected nROI is insensitive to changes in the gamma-ray background, thus allowing satisfactory normalizatio… more
Date: October 28, 2007
Creator: Mitra, S. & Wielopolski, L.
Partner: UNT Libraries Government Documents Department
open access

Solar Radiation and Induction of DNA Damage, Mutations and Skin Cancers.

Description: An understanding of the effects of sunlight on human skin begins with the effects on DNA and extends to cells, animals and humans. The major DNA photoproducts arising from UVB (280-320 nm) exposures are cyclobutane pyrimidine dimers. If unrepaired, they may kill or mutate cells and result in basal and squamous cell carcinomas. Although UVA (320-400 nm) and visible wavelengths are poorly absorbed by DNA, the existing data indicate clearly that exposures to these wavelengths are responsible, in a… more
Date: May 10, 2007
Creator: Setlow, Richard. B.
Partner: UNT Libraries Government Documents Department
open access

High Electron Mobility InN

Description: No Description Available.
Date: February 6, 2007
Creator: Jones, R. E.; Li, S. X.; Haller, E. E.; van Genuchten, H. C. M.; Yu, K. M.; Ager, J. W., III et al.
Partner: UNT Libraries Government Documents Department
open access

Ionization Thresholds of Small Carbon Clusters: Tunable VUVExperiments and Theory

Description: Small carbon clusters (Cn, n = 2-15) are produced in amolecular beam by pulsed laser vaporization and studied with vacuumultraviolet (VUV) photoionization mass spectrometry. The required VUVradiation in the 8-12 eV range is provided by the Advanced Light Source(ALS) at the Lawrence Berkeley National Laboratory. Mass spectra atvarious ionization energies reveal the qualitative relative abundances ofthe neutral carbon clusters produced. By far the most abundant species isC3. Using the tunability … more
Date: July 31, 2007
Creator: Belau, Leonid; Wheeler, Steven E.; Ticknor, Brian W.; Ahmed, Musahid; Leone, Stephen R.; Allen, Wesley D. et al.
Partner: UNT Libraries Government Documents Department
open access

Entrance-channel effects in odd-Z tranactinide compound nucleus reactions

Description: Swiatecki, Siwek-Wilczynska, and Wilczynski's 'Fusion By Diffusion' description [1] of transactinide (TAN) compound nucleus (CN) formation utilizes a three-step model. The first step is the 'sticking', or capture, which can be calculated relatively accurately. The second step is the probability for the formation of a CN by 'diffusion' analogous to that of Brownian motion. Lastly, there exists the probability of the CN 'surviving' deexcitation by neutron emission, which competes with fission and… more
Date: September 1, 2007
Creator: Nelson, S. L.; Gregorich, K. E.; Dragojevic, I.; Dullmann, Ch. E.; Eichler, R.; Folden, C. M., III et al.
Partner: UNT Libraries Government Documents Department
open access

Influence of projectile neutron number on cross section in cold fusion reactions

Description: Elements 107-112 [1,2] have been discovered in reactions between {sup 208}Pb or {sup 209}Bi targets and projectiles ranging from {sup 54}Cr through {sup 70}Zn. In such reactions, the compound nucleus can be formed at excitation energies as low as {approx}12 MeV, thus this type of reaction has been referred to as 'cold fusion'. The study of cold fusion reactions is an indispensable approach to gaining a better understanding of heavy element formation and decay. A theoretical model that successfu… more
Date: September 1, 2007
Creator: Dragojevic, Irena; Dragojevic, I.; Gregorich, K. E.; Dullmann, Ch. E.; Folden, C. M., III; Garcia, M. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Fabrication and Characterization of Cylindrical Light Diffusers Comprised of Shape Memory Polymer

Description: We have developed a technique for constructing light diffusing devices comprised of a flexible shape memory polymer (SMP) cylindrical diffuser attached to the tip of an optical fiber. Devices were fabricated by casting an SMP rod over the cleaved tip of an optical fiber and media blasting the SMP rod to create a light diffusing surface. The axial and polar emission profiles and circumferential (azimuthal) uniformity were characterized for various blasting pressures, nozzle-to-sample distances, … more
Date: January 29, 2007
Creator: Small, W., IV; Buckley, P. R.; Wilson, T. S.; Loge, J. M.; Maitland, K. D. & Maitland, D. J.
Partner: UNT Libraries Government Documents Department
open access

Fabrication and In Vitro Deployment of a Laser-Activated Shape Memory Polymer Vascular Stent

Description: Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an i… more
Date: April 25, 2007
Creator: Baer, G. M.; Small, W., IV; Wilson, T. S.; Benett, W. J.; Matthews, D. L.; Hartman, J. et al.
Partner: UNT Libraries Government Documents Department
open access

Soil carbon, after 3 years, under short-rotation woody crops grown under varying nutrient and water availability.

Description: Abstract Soil carbon contents were measured on a short-rotation woody crop study located on the US Department of Energy’s Savannah River Site outside Aiken, SC. This study included fertilization and irrigation treatments on five tree genotypes (sweetgum, loblolly pine, sycamore and two eastern cottonwood clones). Prior to study installation, the previous pine stand was harvested and the remaining slash and stumps were pulverized and incorporated 30 cm into the soil. One year after harvest soil … more
Date: July 1, 2007
Creator: Sanchez, Felipe, G.; Coleman, Mark; Garten, Charles, T., Jr.; Luxmoore, Robert, J.; Stanturf, John, A. & Wullschleger, Stan D.
Partner: UNT Libraries Government Documents Department
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