Sun-synchronous highly elliptical orbits using low-thrust propulsion

Due to restrictions within the current architecture of the global observing system (GOS), space-based remote sensing of Earth suffers from an acute data-deficit over the critical polar-regions. Currently, observation of high-latitude regions is conducted using composite images from spacecraft in geostationary (GEO) and low-Earth orbits (LEOs) [1]. However, the oblique viewing geometry from GEO-based systems to latitudes above around 55 deg [2] and the insufficient temporal resolution of spacecraft in LEO means there is currently no source of continuous imagery for polar-regions obtained with a data refresh rate of less than 15 minutes, as is typically available elsewhere for meteorological observations

Position sensitive radiation detector

An apparatus and method are disclosed for detecting and locating the origin of a gamma ray in a medical diagnostic imaging system. At least one primary fiber, which is a scintillating optical fiber, is positioned to receive radiation from a gamma ray source. At least one secondary fiber intersects the primary fiber at a non-zero angle. Both fibers have a core surrounded by a cladding, with the claddings of the two fibers in optical contact at an intersection point. Both the primary and secondary fibers are provided with means for detecting light propagated in the fibers. The interaction of radiation such as a gamma ray with the primary fiber will result in the propagation of light in both the primary and secondary fibers, thereby permitting the determination of the site of impact of the gamma ray in the detector, and possibly also enabling the determination of the path of incidence of the gamma ray.Board of Regents, University of Texas Syste

On superconducting instability in non-Fermi liquid: scaling approach

The superconducting instability in a non-Fermi liquid in $d>1$ is considered. For a particular form of the single particle spectral function with homogeneous scaling $A(\Lambda k, \Lambda \omega) = \Lambda^{\alpha} A(k, \omega)$ it is shown that the pair susceptibility is also a scaling function of temperature with power defined by $\alpha$. We find three different regimes depending on the scaling constant. The BCS result is recovered for $\alpha = -1$ and it corresponds to a marginal scaling of the coupling constant. For $\alpha > -1$ the superconducting transition happens above some critical coupling. In the opposite case of $\alpha < -1$ for any fixed coupling the system undergoes a transition at low temperatures. Possible implications for theories of high-$T_c$ with a superconducting transition driven by the interlayer Josephson tunneling are discussed. 1 ps file for fig is attached at the bottom of the tex file.Comment: 10 pages + 1 fig, LA-UR-275

First record of the agave snout weevil, Scyphophorus acupunctatusGyllenhal (Coleoptera: Curculionidae: Dryophthorinae), in Puerto Rico

The agave snout weevil, Scyphophorus acupunctatus Gyllenhal (Coleoptera: Curculionidae: Dryophthorinae), is reported from Puerto Rico for the first time. It was collected on feral sisal, Agave sisalana Perrine (Agavaceae), in the Guánica Dry Forest Reserve in the southwestern part of the island

CO adsorption on (111) and (100) surfaces of the Pt sub 3 Ti alloy. Evidence for parallel binding and strong activation of CO

The CO adsorption on a 40 atom cluster model of the (111) surface and a 36 atom cluster model of the (100) surface of the Pt3Ti alloy was studied. Parallel binding to high coordinate sites associated with Ti and low CO bond scission barriers are predicted for both surfaces. The binding of CO to Pt sites occurs in an upright orientation. These orientations are a consequence of the nature of the CO pi donation interactions with the surface. On the Ti sites the orbitals donate to the nearly empty Ti 3d band and the antibonding counterpart orbitals are empty. On the Pt sites, however, they are in the filled Pt 5d region of the alloy band, which causes CO to bond in a vertical orientation by 5 delta donation from the carbon end

Supporting development for the preliminary design of an intermediate water recovery system

Supporting development of experimental design for water recovery syste

Spin-fluctuation mechanism of superconductivity in cuprates

The theory of superconductivity within the t-J model, as relevant for cuprates, is developed. It is based on the equations of motion for projected fermionic operators and the mode-coupling approximation for the self-energy matrix. The dynamical spin susceptibility at various doping is considered as an input, extracted from experiments. The analysis shows that the superconductivity onset is dominated by the spin-fluctuation contribution. We show that T_c is limited by the spin-fluctuation scale $\Gamma$ and shows a pronounced dependence on the next-nearest-neighbor hopping t'. The latter can offer an explanation for the variation of T_c among different families of cuprates.Comment: Color figure