620 Ingenieurwissenschaften und zugeordnete Tätigkeiten
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We have developed, manufactured and tested a unimorph deformable mirror for space applications based on piezoelectric actuation. The mirror was designed for the correction of low-order Zernike modes with a stroke of several tens of micrometers over a clear aperture of 50 mm. It was successfully tested in thermal vacuum, underwent lifetime tests, and was exposed to random vibrations, sinusoidal vibrations, and to ionizing radiation. We report on design considerations, manufacturing of the mirror, and present the test results. Furthermore, we discuss critical design parameters, and how our mirror could be adapted to serve recently proposed space telescopes such as HDST and TALC.
Over the past 5 years we have developed a new type of unimorph deformable mirror. The main advantages of this mirror technology are · very low surface scattering due to the use of superpolished glass · excellent coatings, even suitable for high power lasers, can be applied · active diameter of the mirrors can be between 10 mm and 100 mm · large strokes can be achieved even for small mirror diameters · integrated monolithic tip/tilt functionality based on a spiral arm design We have modeled these mirrors by analytical models as well as by the finite element method. This allows us to quickly design new mirrors tailored to specific applications. One example is a mirror for laser applications that has a diameter of 10 mm and can achieve a stroke in defocus mode of 5 μm. The stroke for these mirrors scales as the square of the mirror diameter, meaning that we can achieve, for example, a stroke of 125 μm for a mirror of 50 mm diameter. We will present design criteria and tradeoffs for these mirrors. We characterize our mirrors by the maximum stroke they can deliver for various Zernike modes, under the boundary condition that the Zernike mode has to be created with a certain fidelity, usually defined by the Maréchal criterion.
We have developed and manufactured a unimorph deformable mirror for space telescopes based on piezoelectric actuation. The mirror features 44 actuators, has an aperture of 50 mm, and is designed to reproduce low-order Zernike modes with a stroke of several tens of µm. We assessed the space compliance by operating the mirror in thermal vacuum, and exposing it to random and sinusoidal vibrations, as well as to ionizing irradiation. Additionally, the operational life time and the laser power handling capability were tested. The mirror was successfully operated in thermal vacuum at 100 K. We report on the conducted tests and the methods used to evaluate the mirror´s performance, and discuss the compliance with the demanded requirements
Large space telescopes made of deployable and lightweight structures suffer from aberrations caused by thermal deformations, gravitational release, and alignment errors which occur during the deployment procedure. An active optics system would allow on-site correction of wave-front errors, and ease the requirements on thermal and mechanical stability of the optical train. In the course of a project funded by the European Space Agency we have developed and manufactured a unimorph deformable mirror based on piezoelectric actuation. The mirror is able to work in space environment and is designed to correct for large aberrations of low order with high surface fidelity. This paper discusses design, manufacturing and performance results of the deformable mirror.
Trends of changes in waste management and possible optimizations within the waste collection process
(2013)
1. General waste management in Europe 2. Optimization process of disposal logistics a. Technologies (collection systems, vehicles etc.) b. Benchmarking c. Optimization 3. The future and sustainability of waste management
Die anhaltende Diskussion um Wirtschaftlichkeit, Leistungsfähigkeit und Qualität der Dienstleistung veranlasst zunehmend mehr Abfallwirtschaft- und Stadtreinigungsbetreibe sich mit der Frage auseinanderzusetzen, " Wo steht mein Betreib im Vergleich zu anderen und wie muss ich mich als Betrieb positionieren?". Erst Antworten hierzu kann u. A. auch eine Teilnahme an einem brancheninternen Benchmarking-Verfahren liefern.
Die Tigray and Afar Wasser Initiative (TAWI) ist ein Kooperationsprojekt der Mekelle Universität (Äthiopien), der Fachhochschule Münster und der Westfälischen Wilhelms-Universität Münster. Gegenstand der Initiative ist die Wasserversorgung im ländlichen Raum der besonders wasserarmen Regionalstaaten Tigray und Afar im semi-ariden Norden Äthiopiens. Im Untergrund ist häufig noch Wasser zu finden, das gelegentlich auch von Menschen zu landwirtschaftlichen Zwecken extensiv genutzt wird. Dichtwände im Untergrund können dazu dienen, diese Nutzung zu intensivieren und zusätzlich den Landschafts-Wasserhaushalt positiv zu beeinflussen. Die so aufgestauten unterirdischen Wasserspeicher sollen als kleine bzw. kleinste Anlagen dezentral die Versorgungslage kleiner, lokaler Bevölkerungsgruppen verbessern. Gleichzeitig vermeidet die unterirdische Speicherung die Gefahr einer Erhöhung der Inzidenzrate für beispielsweise Malaria, wie sie infolge von oberirdisch angelegten Ponds nachgewiesen worden ist.
Further space exploration in the far-infrared (FIR) requires larger apertures in order to improve the spatial resolution of captured images. To this purpose, the Thinned Aperture Light Collector (TALC) concept of a deployable annular telescope has been recently developed at CEA, which offers novel perspectives for FIR space missions. The consortium ELICSIR consortium of European institutes and companies has been created to improve the technological readiness level (TRL) of its key systems and components.