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An optical spectroscopy approach is demonstrated allowing for critical parameters during RF ablation of cardiac tissue to be evaluated in real time. The method is based on incorporating in a typical ablation catheter transmitting and receiving fibers that terminate at the tip of the catheter. By analyzing the spectral characteristics of the NIR diffusely reflected light, information is obtained on such parameters as, catheter-tissue proximity, lesion formation, depth of penetration of the lesion, formation of char during the ablation, formation of coagulum around the ablation site, differentiation of ablated from healthy tissue, and recognition of micro-bubble formation in the tissue.

High β plasmas in the National Spherical Torus Experiment (NSTX) operate in the overdense regime, allowing the electron Bernstein wave (EBW) to propagate and be strongly absorbed/emitted at the electron cyclotron resonances. As such, EBWs may provide local electron heating and current drive. For these applications, efficient coupling between the EBWs and electromagnetic waves outside the plasma is needed. Thermal EBW emission (EBE) measurements, via oblique B-X-O double mode conversion, have been used to determine the EBW transmission efficiency for a wide range of plasma conditions on NSTX. Initial EBE measurements in H-mode plasmas exhibited strong emission before the L-H transition, but the emission rapidly decayed after the transition. EBE simulations show that collisional damping of the EBW prior to the mode conversion (MC) layer can significantly reduce the measured EBE for Te < 20 eV, explaining the observations. Lithium evaporation was used to reduce EBE collisional damping near the MC layer. As a result, the measured B-X-O transmission efficiency increased from < 10% (no Li) to 60% (with Li), consistent with EBE simulations.

A fully microscopic calculation of inelastic proton scattering off {sup 208}Pb is presented, and compared to experimental scattering data for incident proton energies between 65 and 201 MeV. By constructing the nucleon-nucleus interaction through the folding of nuclear structure information with a reliable nucleon-nucleon effective interaction that has no adjusted parameter, a consistent framework is built, for probing the influence of different descriptions of nuclear structure on nucleon inelastic scattering predictions. The absence of phenomenological normalization in this framework guarantees a unique and unambiguous interpretation of our calculations in terms of quality of the underlying nuclear structure description: a feature that had been reserved, until recently, to the electron probe. This tool is used to investigate the effect of long range correlations embedded in excited states, on calculated inelastic observables, demonstrating the sensitivity of nucleon scattering predictions to details of the nuclear structure.

An algorithm was developed for the two-dimensional (2D) reconstruction of truncated and non-truncated uniformly attenuated data acquired from single photon emission computed tomography (SPECT). The algorithm is able to reconstruct data from half-scan (180o) and short-scan (180?+fan angle) acquisitions for parallel- and fan-beam geometries, respectively, as well as data from full-scan (360o) acquisitions. The algorithm is a derivative, backprojection, and Hilbert transform (DBH) method, which involves the backprojection of differentiated projection data followed by an inversion of the finite weighted Hilbert transform. The kernel of the inverse weighted Hilbert transform is solved numerically using matrix inversion. Numerical simulations confirm that the DBH method provides accurate reconstructions from half-scan and short-scan data, even when there is truncation. However, as the attenuation increases, finer data sampling is required.

Binary Pt/Pd nanoparticles were synthesized by localized overgrowth of Pd on cubic Pt seeds for the investigation of electrocatalytic formic acid oxidation. The binary particles exhibited much less self-poisoning and a lower activation energy relative to Pt nanocubes, consistent with the single crystal study.

Temporary trapping of atomic xenon in functionalized cryptophane cages makes the high sensitivity of hyperpolarized (hp) 129Xe available for highly specific NMR detection of biomolecules like proteins in solution. Here, we study the signal transfer onto a reservoir of unbound hp xenon by gating the residence time of the nuclei in the cage through the temperature-dependent exchange rate. Temperature changes were detectable immediately as an altered reservoir signal and yielded a sensitivity of 0.6 K. The temperature response is adjustable with lower concentrations of caged xenon providing more sensitivity at higher temperatures and allows ultra-sensitive detection of such molecular cages at 310 K. Functionalized cryptophane could be detected at concentrations as low as 10nM which corresponds to a 4000-fold sensitivity enhancement compared to conventional detection. This sensitivity makes hp-NMR capable of detecting such constructs in concentrations far belowthe detection limit by UV-visible light absorbance.

Tritium movement and accumulation in the Next Generation Nuclear Plant (NGNP) employing either a high-temperature electrolysis (HTE) process or a thermochemical water-splitting Sulfur-Iodine (SI) process to produce hydrogen is estimated by a numerical code, THYTAN, as a function of design, operational and material parameters. Estimated tritium concentrations in the hydrogen product and in the process chemicals of the hydrogen plant using the HTE process are slightly higher than the limit in drinking water defined by the U.S. Environmental Protection Agency (EPA) and in effluent at the boundary of an unrestricted area defined by the U.S. Nuclear Regulatory Commission (NRC), respectively. Estimated tritium concentrations in the NGNP using the SI hydrogen production process are significantly higher, and are largely affected by undetermined parameters (i.e., tritium permeability of heat exchanger materials, hydrogen concentration in the helium energy transport fluids, equilibrium constant of the tritium isotope exchange reaction between HT and H{sub 2}SO{sub 4}). These parameters should be measured or estimated in the near future, as should the tritium generation and release rate from the NGNP nuclear reactor core. Decreasing the tritium permeation rate between the primary and secondary heat transport circuits is an effective measure to decrease the tritium concentrations in the …

A 28 GHz electron cyclotron heating (ECH) and electron Bernstein wave heating (EBWH) system has been proposed for installation on the National Spherical Torus Experiment (NSTX). A 350 kW gyrotron connected to a fixed horn antenna is proposed for ECH-assisted solenoid-free plasma startup. Modeling predicts strong first pass on-axis EC absorption, even for low electron temperature, Te ~ 20 eV, Coaxial Helicity Injection (CHI) startup plasmas. ECH will heat the CHI plasma to Te ~ 300 eV, providing a suitable target plasma for 30 MHz high-harmonic fast wave heating. A second gyrotron and steered O-X-B mirror launcher is proposed for EBWH experiments. Radiometric measurements of thermal EBW emission detected via B-X-O coupling on NSTX support implementation of the proposed system. 80% B-X-O coupling efficiency was measured in L-mode plasmas and 60% B-X-O coupling efficiency was recently measured in H-mode plasmas conditioned with evaporated lithium. Modeling predicts local on-axis EBW heating and current drive using 28 GHz power in β ~ 20% NSTX plasmas should be possible, with current drive efficiencies ~ 40 kA/MW.