Material standards design for minimum zone fitting of freeform optics

International audienceIn most cases, ultra-high-precision coordinate measuring machines (CMMs) are used to measure manufactured parts especially in the presence of freeform surfaces. The obtained data should be then processed to determine a quality measure of the surface. The least value of peak-to-valley (PV) is the widely used quality measure since it conforms to the ISO Geometrical and Product Specification (GPS) standards. To determine the minimum value of PV, a number of fitting methods exist but minimum zone fitting is the most suitable since it directly minimizes the PV. In the measurement process, fitting algorithms are essential elements. For this reason, their quality must be assessed as well; this could be achieved using either softgauges or material artefacts. In this paper, a design of a reference thermo-invariant material standard for minimum zone fitting is suggested and manufactured. The artefact was then measured by a number of partners participating to the FreeFORM 15SIB-01 project so as a comparison could be made in the light of gathered measurements

Design status of ASPIICS, an externally occulted coronagraph for PROBA-3

The "sonic region" of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The proposed PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), with its novel design, will be the first space coronagraph to cover the range of radial distances between ~1.08 and 3 solar radii where the magnetic field plays a crucial role in the coronal dynamics, thus providing continuous observational conditions very close to those during a total solar eclipse. PROBA-3 is first a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future European missions, which will fly ASPIICS as primary payload. The instrument is distributed over two satellites flying in formation (approx. 150m apart) to form a giant coronagraph capable of producing a nearly perfect eclipse allowing observing the sun corona closer to the rim than ever before. The coronagraph instrument is developed by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent improvements and design updates of the ASPIICS instrument as it is stepping into the detailed design phase

Characterization of Supersonic Compressible Fluid Flow Using High-Speed Interferometry

This paper presents a very effective interference technique for the sensing and researching of compressible fluid flow in a wind tunnel facility. The developed technique is very sensitive and accurate, yet easy to use under conditions typical for aerodynamic labs, and will be used for the nonintrusive investigation of flutter in blade cascades. The interferometer employs a high-speed camera, fiber optics, and available “of-the-shelf” optics and optomechanics. The construction of the interferometer together with the fiber optics ensures the high compactness and portability of the system. Moreover, single-shot quantitative data processing based on introducing a spatial carrier frequency and Fourier analysis allows for almost real-time quantitative processing. As a validation case, the interferometric system was successfully applied in the research of supersonic compressible fluid discharge from a narrow channel in a wind tunnel. Density distributions were quantitatively analyzed with the spatial resolution of about 50 μm. The results of the measurement revealed important features of the flow pattern. Moreover, the measurement results were compared with Computational Fluid Dynamics (CFD) simulations with a good agreement

Digital Holographic Method for Piezoelectric Transformers Vibration Analysis

The paper describes a holographic method for vibration analysis in nanometer range. The method was successfully applied on different types of piezoelectric transformers and the measurement results are introduced. To proof the reliability of the method it was done a comparing simultaneous measurement of a piezoelectric component by the holographic method and the well-established single-point interferometric method. Results showing the minimal deviation of both methods are presented in the final part of the paper

Tree productions of Capek's The Robber at The Vinohrady Theater

The aim of the bachelor thesis is to characterize three last stage productions of the Vinohrady theatre of the play Loupeznik by the well known playwright, author and a democrat Karel Čapek. Karel Čapek was one of the most remarkable authors of the 1920s and 1930s. The author of this thesis attempts to make a reconstruction of the last three stage productions of Loupeznik at the Vinohrady theatre based on available infomation found. The first and oldest one being stage production of 1972 by the director Frantisek Stepanek. The second one being the stage production by director Jan Novak of 1988. And the last and newest one is the stage production by director Thomas Topfer of 2015. The more detailed analysis will be provided to the first and third production respectively because of the more information available for these including the video recording of these two productions. On the other hand, for the second production very little material being available and thus to reconstruct this 1988 one based on the material was very difficult. In the order to reconstruct the productions the author bases his research upon archival theater reviews and studies in particular periodicals, photographical material from the productions and in some cases also audiovisual recordings. Other resources include also the...Bakalářská práce si klade za cíl popsat a charakterizovat poslední tři inscenace Loupežníka Karla Čapka v Divadle na Vinohradech. Autor postupuje metodou rekonstrukce inscenace, tyto tři poslední inscenace poté podrobuje detailnější analýze. Jedná se o inscenaci Františka Štěpánka z roku 1972, inscenaci Jana Nováka z roku 1988 a inscenaci Tomáše Töpfera z roku 2015. Inscenace, ke kterým je k dispozici audiovizuální záznam, budou podrobeny detailnější analýze. Při analýze druhé inscenace se autor práce potýkal s nedostatkem informací. Její rekonstrukce proto byla velmi obtížná. Při popisu inscenací autor vychází z recenzí z dobových periodik, fotografií k inscenacím a ve dvou ze tří zmíněných případů také z videozáznamu. Dále z knih o Karlu Čapkovi a jeho díle i z poskytnutých rozhovorů s herečkami Danielou Kolářovou a Hanou Maciuchovou. Pozornost je věnována také historickému kontextu a tehdejším společenským a divadelním poměrům, stejně tak také poměrům v činohře Divadla na Vinohradech, které ovlivňovaly zdejší umělecké působení.Departement of Theatre StudiesKatedra divadelní vědyFilozofická fakultaFaculty of Art