Active shape correction of a thin glass/plastic X-ray mirror

Optics for future X-ray telescopes will be characterized by very large aperture and focal length, and will be made of lightweight materials like glass or plastic in order to keep the total mass within acceptable limits. Optics based on thin slumped glass foils are currently in use in the NuSTAR telescope and are being developed at various institutes like INAF/OAB, aiming at improving the angular resolution to a few arcsec HEW. Another possibility would be the use of thin plastic foils, being developed at SAO and the Palermo University. Even if relevant progresses in the achieved angular resolution were recently made, a viable possibility to further improve the mirror figure would be the application of piezoelectric actuators onto the non-optical side of the mirrors. In fact, thin mirrors are prone to deform, so they require a careful integration to avoid deformations and even correct forming errors. This however offers the possibility to actively correct the residual deformation. Even if other groups are already at work on this idea, we are pursuing the concept of active integration of thin glass or plastic foils with piezoelectric patches, fed by voltages driven by the feedback provided by X-rays, in intra-focal setup at the XACT facility at INAF/OAPA. In this work, we show the preliminary simulations and the first steps taken in this project

A non-parametric assessment of the effects of the Euro on GVC trade

This work makes a fresh contribution to the long-standing debate on the trade effects of the euro. Its novelty lies in the joint use of trade in value added and non-parametric techniques. Specifically: i) we measure bilateral trade in value added to proxy backward and forward global value chain (GVC) linkages within the eurozone; ii) we compare these outcomes for treated and untreated units by disentangling long-term and short-term effects of the euro, taking advantage of panel data and combining matching and difference-in-difference approaches. Results show no significant evidence of a positive post-assessment of the euro effect on intra-eurozone GVC trade. These findings are robust to a set of sensitivity tests such as looking both at the intensity and composition of trade in value added flows and extending the sample to various control groups and datasets. We believe that our findings contribute to the long-standing debate on the euro by complementing the previous empirical evidence and providing an overall coherent and informative picture for policymaking

RIM FOR WHEEL WITH SENSOR AND WHEEL COMPRISING SAID RIM

A rim for wheel is described comprising a measuring system for detecting the vertical load applied to the wheel. The measuring system comprises a sensor adapted to detect a deformation of the rim and to transmit a deformation signal to a processing unit. The processing unit receives an output signal of the sensor related to the deformation of the rim detected, and determines the vertical load applied to the wheel

ESPRESSO front end: modular opto-mechanical integration for astronomical instrumentation

The opto-mechanical conceptual design for the Front-End unit and the calibration unit of the ESPRESSO Spectrograph is described in this paper. The front end system exploits a modular concept. Each FEU receive the beam directly from the relative Telescope Coudé Train and the calibration light from the calibration unit. On the other side the FEU feeds the fibers that carry the light to the spectrograph, corresponding in number and size to the scientific observing modes conceived for Espresso. The selection is made through a Toggling Unit. Purpose of the Front/End is to provide the needed connection between the input signal, i.e. Object light, Sky light, Calibration light, and the given output fiber in any of the foreseen observing modes