The use of FRPs in seismic repair and retrofit: experimental verification

The application of FRPs in the seismic repair and retrofit of structures is addressed. The results from a few tests on full-scale structures, repaired and/or retrofitted with composites, performed at the ELSA laboratory are presented and discussed

Study of certain launching techniques using long orbiting tethers

A study of the basic equations governing orbital transfers using long orbiting tethers is presented. A very simple approximation to the general transfer equation is derived for the case of short tethers and low eccentricity orbits. Numerical examples are calculated for the case of injection into a circular orbit from a platform in eccentric orbit and injection into eccentric orbit from a platform in circular orbit. For the case of long tethers, a method is derived for reducing tether mass and increasing payload mass by tapering the tether to maintain constant stress per unit of tether cross section. Formulas are presented for calculating the equilibrium orbital parameters taking into account the mass of the platform, tether, and payload

Gravitational spectra from direct measurements

A simple rapid method is described for determining the spectrum of a surface field from harmonic analysis of direct measurements along great circle arcs. The method is shown to give excellent overall trends to very high degree from even a few short arcs of satellite data. Three examples are taken with perfect measurements of satellite tracking over a planet made up of hundreds of point-masses using (1) altimetric heights from a low orbiting spacecraft, (2) velocity residuals between a low and a high satellite in circular orbits, and (3) range-rate data between a station at infinity and a satellite in highly eccentric orbit. In particular, the smoothed spectrum of the Earth's gravitational field is determined to about degree 400(50 km half wavelength) from 1 D x 1 D gravimetry and the equivalent of 11 revolutions of Geos 3 and Skylab altimetry. This measurement shows there is about 46 cm of geoid height remaining in the field beyond degree 180

Spacelike hypersurfaces in standard static spacetimes

In this work we study spacelike hypersurfaces immersed in spatially open standard static spacetimes with complete spacelike slices. Under appropriate lower bounds on the Ricci curvature of the spacetime in directions tangent to the slices, we prove that every complete CMC hypersurface having either bounded hyperbolic angle or bounded height is maximal. Our conclusions follow from general mean curvature estimates for spacelike hypersurfaces. In case where the spacetime is a Lorentzian product with spatial factor of nonnegative Ricci curvature and sectional curvatures bounded below, we also show that a complete maximal hypersurface not intersecting a spacelike slice is itself a slice. This result is obtained from a gradient estimate for parametric maximal hypersurfaces.Comment: 50 page

Coupling of a Copper Dye with a Copper Electrolyte: the Birth of Sustainable “Full-Copper” Dye-Sensitized Solar Cells

To have enough clean and low cost energy for the future is one of the world\u2019s most important challenges. Since the discovery of Gr\ue4tzel-type dye-sensitized solar cells (DSSCs) as a convenient way for harnessing the energy of the sun and converting it into electricity, there has been a lot of effort to improve the photo-conversion efficiency, trying to optimize the sensitizer and the redox mediators. Until recently, the most efficient DSSCs were based on ruthenium complexes as dye and the iodide/triiodide couple as redox mediator. However, ruthenium is one of the rarest and most expensive metal, and this is a drawback in the design of low-cost DSSCs. Photophysical, economic, and environmental considerations make copper(I) coordination compounds interesting alternatives to ruthenium dyes [1-2]. Besides, it was found that Cu-based mediators can outperform both iodine-based and Co-based electrolytes [2]. These observations were the springboard for the first \u201cfull-copper\u201d DSSCs in which a copper(I) dye is coupled with a copper(I)/(II) electron shuttle, of great interest for the development of novel low cost and environmentally friendly DSSCs. This presentation is on the birth of \u201cfull-copper\u201d DSSCs. First, it will be shown how homoleptic and heteroleptic copper(I) dyes can be coupled with the common I\u2013/I3\u2013 redox couple to prepare DSSCs with a good efficiency. Then, some examples of the use of homoleptic Cu(I)/(II) mediators, in combination with both ruthenium(II) dyes and organic dyes, will be given. Finally, the coupling of a copper dye with a copper electrolyte as a fascinating route for sustainable \u201cfull-copper\u201d DSSCs will be presented. [1] C. E. Housecroft, E. C. Constable, Chem. Soc. Rev. 2015, 44, 8386- 8398. [2] M. Magni, P. Biagini, A. Colombo, C. Dragonetti, D. Roberto, A. Valore Coord. Chem. Rev. 2016, 322, 69-9

On the first Gaussian map for Prym-canonical line bundles

We prove by degeneration to Prym-canonical binary curves that the first Gaussian map of the Prym canonical line bundle $\omega_C \otimes A$ is surjective for the general point [C,A] of R_g if g >11, while it is injective if g < 12.Comment: To appear in Geometriae Dedicata. arXiv admin note: text overlap with arXiv:1105.447

An alternative option to the dual-probe out-of-ecliptic mission via Jupiter swingby

The possibility of having a high-inclination out-of-the-ecliptic probe complemented by a second probe going from Jupiter to the sun along a rectilinear path (at least for the segment from 0.3 a.u. inward to the sun) is theoretically examined. Orbit calculations of spacecraft trajectories are included