Electronic contribution to the oscillations of a gravitational antenna

We carefully analyse the contribution to the oscillations of a metallic gravitational antenna due to the interaction between the electrons of the bar and the incoming gravitational wave. To this end, we first derive the total microscopic Hamiltonian of the wave-antenna system and then compute the contribution to the attenuation factor due to the electron-graviton interaction. As compared to the ordinary damping factor, which is due to the electron viscosity, this term turns out to be totally negligible. This result confirms that the only relevant mechanism for the interaction of a gravitational wave with a metallic antenna is its direct coupling with the bar normal modes.Comment: 25 pages, no figure

The Large-Scale Polarization Explorer (LSPE)

The LSPE is a balloon-borne mission aimed at measuring the polarization of the Cosmic Microwave Background (CMB) at large angular scales, and in particular to constrain the curl component of CMB polarization (B-modes) produced by tensor perturbations generated during cosmic inflation, in the very early universe. Its primary target is to improve the limit on the ratio of tensor to scalar perturbations amplitudes down to r = 0.03, at 99.7% confidence. A second target is to produce wide maps of foreground polarization generated in our Galaxy by synchrotron emission and interstellar dust emission. These will be important to map Galactic magnetic fields and to study the properties of ionized gas and of diffuse interstellar dust in our Galaxy. The mission is optimized for large angular scales, with coarse angular resolution (around 1.5 degrees FWHM), and wide sky coverage (25% of the sky). The payload will fly in a circumpolar long duration balloon mission during the polar night. Using the Earth as a giant solar shield, the instrument will spin in azimuth, observing a large fraction of the northern sky. The payload will host two instruments. An array of coherent polarimeters using cryogenic HEMT amplifiers will survey the sky at 43 and 90 GHz. An array of bolometric polarimeters, using large throughput multi-mode bolometers and rotating Half Wave Plates (HWP), will survey the same sky region in three bands at 95, 145 and 245 GHz. The wide frequency coverage will allow optimal control of the polarized foregrounds, with comparable angular resolution at all frequencies.Comment: In press. Copyright 2012 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibite

Plastics design: integrating TRIZ creativity and semantic knowledge portals

Polymers are substituting metallic alloys in every field of mechanical application; in plastics design the material properties affect designer's choice more heavily than in other cases, but also available manufacturing technologies have a deep influence on the project. All of these considerations can be summarized in the concept that a wide knowledge of polymer behaviour and technology is required and that in plastics design a new approach should be used: so new design tools must be adopted, as creativity supporting software, integrated with the prototyping capabilities offered by computer-aided engineering systems, to guide the development of new solutions. The aim of this work is to show how the integration of modern design tools with creativity management techniques constitutes an effective procedure to enhance the capability of developing innovative products. In this paper the use of the Theory of Inventive Problem Solving (TRIZ) is proposed to approach the redesign of structural parts from metals to polymers. To supply the designer with all the information he/she may need in this activity, a knowledge portal based on semantic capabilities of modern text mining technology has been built: the design of a polymeric wheel is taken as the opportunity to show how these design tools can organize and conduct to realizable solutions. The integrated adoption of knowledge-based tools both for the conceptual design phase (TRIZ-based applications) and for the detailed design phase (Semantic Knowledge portal) has provided satisfactory results in terms of augmented creativity and design efficiency

Seat assist device for elderly and disabled people

A seat assist device comprising: a base (1) having a support surface (1a) to be positioned on the seat surface of a chair, armchair or the like; a seat (2) defining a seat surface (2a) with a front side (2b), the seat (2) being movable between a closed configuration, wherein said seat (2) is adjacent to the base (1) with the seat surface (2a) substantially horizontal, and an open configuration, wherein the seat (2) is lifted in relation to the base (1) to assist the assumption of a standing position by a user sitting on the seat (2) with the legs projecting over said front side (2b); and connection means (3) connecting the seat (2) and the base (1) for ensuring the motion of the seat (2) between the open and closed configurations; the connection means (3) comprising articulation means (4), for bringing the seat (2) in the open configuration in a position which is translated in relation to the base (1), both vertically and horizontally in a frontal direction, and at the same time tilted with the front side in a downward direction