Procedure for the rapid evaluation of carbon stripper foils

Evaluation of the average lifetime of carbon stripper foils is described in which a beam of 20 keV ions is used to simulate the beam from a high energy accelerator. The method is used to evaluate different methods of foil fabrication. (GHT

Electromagnetic Decay of Giant Resonances

Coincidence experiments were done to investigate the photon and neutron emission from the giant resonance regions of /sup 208/Pb and /sup 90/Zr using the ORNL Spin Spectrometer, a 72-segment NaI detector system. We have determined the total gamma-decay probability, the ground-state gamma branching ratio, and the branching ratios to a number of low-lying states as a function of excitation energy in /sup 208/Pb to approx.15 MeV. Similar data were also obtained on /sup 90/Zr. The total yield of ground-state E2 gamma radiation in /sup 208/Pb and the comparative absence of such radiation in /sup 90/Zr can only be understood if decay of compound (damped) states is considered. Other observations in /sup 208/Pb include the absence of a significant branch from the giant quadrupole resonance (GQR) to the 3/sup -/ state at 2.6 MeV, a strong branch to a 3/sup -/ state at 4.97 MeV from the same region, and transitions to various 1/sup -/ states between 5 to 7 MeV from the E* approx. 14 MeV region (EO resonance)

Surface Energy Budgets of Arctic Tundra During Growing Season

This study analyzed summer observations of diurnal and seasonal surface energy budgets across several monitoring sites within the Arctic tundra underlain by permafrost. In these areas, latent and sensible heat fluxes have comparable magnitudes, and ground heat flux enters the subsurface during short summer intervals of the growing period, leading to seasonal thaw. The maximum entropy production (MEP) model was tested as an input and parameter parsimonious model of surface heat fluxes for the simulation of energy budgets of these permafrost‐underlain environments. Using net radiation, surface temperature, and a single parameter characterizing the thermal inertia of the heat exchanging surface, the MEP model estimates latent, sensible, and ground heat fluxes that agree closely with observations at five sites for which detailed flux data are available. The MEP potential evapotranspiration model reproduces estimates of the Penman‐Monteith potential evapotranspiration model that requires at least five input meteorological variables (net radiation, ground heat flux, air temperature, air humidity, and wind speed) and empirical parameters of surface resistance. The potential and challenges of MEP model application in sparsely monitored areas of the Arctic are discussed, highlighting the need for accurate measurements and constraints of ground heat flux.Plain Language SummaryGrowing season latent and sensible heat fluxes are nearly equal over the Arctic permafrost tundra regions. Persistent ground heat flux into the subsurface layer leads to seasonal thaw of the top permafrost layer. The maximum energy production model accurately estimates the latent, sensible, and ground heat flux of the surface energy budget of the Arctic permafrost regions.Key PointThe MEP model is parsimonious and well suited to modeling surface energy budget in data‐sparse permafrost environmentsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/1/jgrd55584.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150560/2/jgrd55584_am.pd

Robust image analysis with sparse representation on quantized visual features

10.1109/TIP.2012.2219543IEEE Transactions on Image Processing223860-871IIPR

Progress, Status, and Plans for the HRIBF Project

Over the last three years, the Holifield accelerator system has been reconfigured into a first-generation radioactive ion beam facility, the HRIBF, a national user facility for RIB research. The construction and reconfiguration have been completed and the equipment commissioning and beam development phases have started. The progress to date, the present status, and future plans will be given. The special problems connected with the production and acceleration of RIBs will be discussed

Status Report for the Holifield Radioactive Ion Beam Facility

In 1992, the HHIRF became a project to develop a first-generation radioactive ion beam facility, the HRIBF, a national user facility for RIB research. Intense beams from ORIC will produce radioactive atoms as reaction products in thick targets using an ISOL-type target-ion source mounted on a 300-kV RIB injector. These radioactive atoms will be ionized, mass analyzed, charge exchanged, accelerated to ground potential, and analyzed again to separate isobars with a second-stage mass analyzer. The resulting RIBs will be injected into the tandem and accelerated to energies of interest for nuclear physics and astrophysics studied. The construction phase of the project has been completed. A report on the status and progress developing the facility is given, along with the long term development plans

Status Report on the Holifield Radioactive Ion Beam Project

In July 1992, a project was started to reconfigure the Holifield Heavy Ion Research Facility (HHIRF) to form the Holifield Radioactive Ion Beam Facility (HRIBF). This ORNL project to produce medium-intensity, proton-rich, radioactive ion beams (RIBS) for astrophysics, nuclear physics, and applied research was first described to the SNEAP community at Chalk River in 1992. To briefly review, radioactive ions will be produced by light ion beams from the Oak Ridge Isochronous Cyclotron (ORIC) striking a target in an Isotope Separator On-Line (ISOL)-type target-ion source assembly. The radioactive ions will be converted to negative ions either directly in the ion source or by charge exchange following positive ionization. After acceleration to approximately 300 keV, these ions will be injected into the tandem accelerator for acceleration to higher energies. Successful production and acceleration of RIBs requires changes in the existing accelerators, development of the target-ion source, and construction of a new high-voltage injector and new injection beam line for the tandem accelerator. A floor plan of the facility as it should be when the project is finished is given. Progress has been made in a areas and will be detailed starting with the cyclotron

Differential regulation of collagenase gene expression by retinoic acid receptors--alpha, beta and gamma.

The mechanisms involved in retinoic acid (RA)-mediated regulation of the collagenase gene in a rabbit synovial fibroblast cell line (HIG82) were investigated. When HIG82 cells are cotransfected with expression vectors containing cDNAs for retinoic acid receptor (RAR) alpha 1, beta 2, or gamma 1 and collagenase promoter-driven CAT reporter constructs, only RAR-gamma 1 represses basal CAT expression upon RA treatment, while RAR-alpha 1, beta 2, and gamma 1 all suppress phorbol-induced CAT expression. Thus, transcriptional regulation of collagenase by RA is mediated by RARs in an RAR-type specific manner. Using mutational and deletional analysis, we find that interaction between elements within 182 bp collagenase promoter plays an important role in this process. In addition, cotreatment with RA results in a decrease of phorbol-induced mRNA levels of fos and jun, and binding of nuclear proteins to an AP-1 oligonucleotide. Furthermore, RA-induced nuclear protein(s) specifically bind to a 22 bp sequence (-182 to -161) of the collagenase promoter. We propose that RA-mediated regulation of the collagenase gene depends on the availability and interaction of specific RARs with multiple DNA elements within the promoter and with transcription factors, including AP-1 related proteins